U.S. Department of T r a n s p o r t a t i o nResearch and S p e c i a l Programs A d m i n i s t r a t i o nJ o h n A . V o l p e N a t i o n a l T r a n s p o r t a t i o n S y s t e m s Center

P R O J E C T M A N A G E M E N T B I N D E R

U S E N V I R O N M E N T A L P R O T E C T I O N A G E N C YREGION 8

L I B B Y , M O N T A N A - E M E R G E N C Y R E S P O N S EA S S E S S M E N T O F A S B E S T O S C O N T A M I N A T I O N

November 30,1999

c1D e s i g n a t i o n : D 4700 -91 ( R e a p p r o v e d 1998)

S t a n d a r d G u i d e f o rS o i l S a m p l i n g f r o m t h e Vadose Zone 1

T h i s standard is issued under the f i x e d d e s igna t i on D 4700: the number i m m e d i a t e l y f o l l o w i n g the d e s ignat i on i n d i c a t e s the year oforiginal a d o p t i o n or, in the case of revision, the year of last revision. A number in parenthe se s i n d i c a t e s the year of la s t r eapproval . Asuperscript ep s i lon (e) indicates an editorial change since the last revision or reapproval .e1 N O T E — P a r a g r a p h 1.7 was added edi tor ia l ly January 1999. ______ __________

pour;3--tnay!

1. S c o p e1.1 T h i s guide addres se s procedures that may be used for

obtaining soil sample s f rom the vadose zone (unsaturatedzone). S a m p l e s can be col lec ted for a variety of reasonsinc lud ing the f o l l o w i n g :

1.1.1 S t r a t i g r a p h i c d e s c r i p t i o n ,1.1.2 H y d r a u l i c c onduc t iv i ty t e s t i n g ,1.1.3 Moi s ture content measurement,1.1.4 Mois ture release curve construction.1.1.5 G e o t e c h n i c a l t e s t i n g ,1.1.6 S o i l gas analyse s ,1.1.7 Microorganism extraction, or1.1.8 Pore l iquid and soils chemical analyses.1.2 T h i s guide f o c u s e s on methods that provide soil samples

for chemical analyses of the soil or contained l i qu id s or"ontaminants. However, comments on how methods may be

•jdif ied for other ob j e c t ive s are inc luded.1.3 T h i s guide does not describe s a m p l i n g methods for

l i t h i f i e d d e p o s i t s and rocks ( for e xampl e , sandstone, shale, t u f f ,grani t e).

1.4 In general, it is prudent to per form all f i e l d work with atleas t two p e o p l e present. T h i s increases s a f e t y and f a c i l i t a t e se f f i c i e n t data collection.

1.5 The values stated in inch-pound units are to be regardedas the standard. The SI units given in parentheses are forinformation only.

1.6 This standard does not purport to address all of thesafety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.

1.7 This guide offers an organized collection of informationor a series of options and does not recommend a specificcourse of action. This document cannot replace education orexperience and should be used in conjunction with professionaljudgment. Not all aspects of this guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care by which the adequacy ofa given professional service must be judged, nor should this

' T h i s guide is under the j u r i s d i c t i o n of ASTM Committee D-18 on Soi l andRockand is the direct r e s p o n s i b i l i t y of Subcommittee D18.21 on Ground Water andVados e Zone I n v e s t i g a t i o n s .

Current ed i t i on approved July 15 , 1991. P u b l i s h e d S e p t e m b e r 1991.

document be applied without consideration of a project's manyunique aspects. The word "Standard" in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.2. Referenced Documents

2.1 ASTM Standards:D 420 Practice for I n v e s t i g a t i n g and S a m p l i n g Soi l and

Rock for Engineering Purposes 2

D 653 T e r m i n o l o g y Relat ing to S o i l , Rock, and ContainedF l u i d s 2

D 1452 Pract i ce for S o i l I n v e s t i g a t i o n and S a m p l i n g byAuger Borings 2

D 1586 Method for Pene tra t i on T e s t and S p l i t - B a r r e l Sam-p l i n g o f S o i l s 2

D 1587 Method for T h i n - W a l l e d Tube S a m p l i n g of S o i l s 2

D 2488 Practice for Description and I d e n t i f i c a t i o n of Soils(Visual-Manual Procedure) 2

D 2607 C l a s s i f i c a t i o n of Peats, Mosses, Humus , and Re-lated Product s 2

D 3550 Method for Ring-Lined Barrel S a m p l i n g of S o i l s 2

D 4083 Prac t i c e for Des cr ip t i on of F r o z e n S o i l s (Visual-Manual Proc edure) 2

D 4220 Pract i c e f o r . Pre s erv ing and T r a n s p o r t i n g SoilS a m p l e s 2

3. T e r m i n o l o g y3.1 Definitions:3.1.1 Except where noted , all terms and symbols in this

guide are in accordance with the f o l l o w i n g publications. Inorder of consideration they are:

3.1.1.1 T e r m i n o l o g y D 653.3.1.1.2 Compilation of ASTM Standard Terminology,3 and3.1.1.3 Webster's New Collegiate Dictionary. 4

3.1.2 For d e f i n i t i o n s and c l a s s i f i c a t i o n s of soil re lated termsused, r e f e r to Practice D 2488 and T e r m i n o l o g y D 653. Addi-tional terms that require c l a r i f i c a t i o n are denned in 3.2.

3.2 Definitions of Terms Specific to This Standard:3.2.1 cascading water—perched ground water that enters'2 Annual Book of ASTM Standards. Vol 04.08.3 Compilation of ASTM Standard Terminology, S i x t h ed i t ion, ASTM. 1916 R*1

St., Phi la . , PA 19103, 1986.4 Webster's New Collegiate Dictionary, Fifth ed i t i on. 1977.

816

ct'smanye of thisapproved

S o i l andContained

m p l i n g byiarrel Sam-3 of S o i l s 2

"on^ro oils

ig of S o i l s 2

) i l s ( V i s u a l -p o r t i n g S o i l

abol s in thisp l i ca t i on s . In

nology,3 a4re la t ed terms

D 653. Addi-i in 3.2.dard:r that enters a

A S T M . l 9 1 6 R a c e

D4700casing via cracks or uncovered p e r f o r a t i o n s , t r i c k l i n g , or

pouring down the in s id e of the casing.3.2.2 sludge—a water charged sedimentary d e p o s i t .3.2.2.1 Discussion—The water-formed sedimentary depo s i t

may include all su spended s o l i d s carried by the water and tracee l ements that were in solution in the water. S l u d g e u sua l ly doesnot cohere s u f f i c i e n t l y to retain its phys i cal shape whenmechanical means are used to remove it f r om the surface onwhich it d e p o s i t s , but it may be baked in p l a c e and be adherent.4. Summary of G u i d e

4.1 S a m p l i n g vadose zone soil involves inserting into theground a device that retains and recovers a sample . Devicesand sys t ems for vadose zone s a m p l i n g are d i v i d e d into twogeneral groups , namely the f o l l o w i n g : sampler s used in con-j u n c t i o n with hand operated devices; and samplers used inconjunc t ion with m u l t i p u r p o s e or auger d r i l l rigs. T h i s guidediscusses these groups and their associated pract ice s .

4.2 The d i s cu s s ion of each device is organized into threesections, d e s c r i b ing the device , de s cr ib ing s a m p l i n g methods ,and l imi ta t ions and advantages of its use.

4.3 T h i s guide i d e n t i f i e s and describes a number of sam-p l i n g methods and samplers . It is advi sab l e to consult availables i t e - s p e c i f i c geo log i ca l and hydro log i ca l data to assist indetermining the s a m p l i n g method and sampler best suited for as p e c i f i c p r o j e c t . It is also advi sable to contact a local f i rmproviding the services required as not all s a m p l i n g and dr i l l ingmethods described in this guide are available nationwide.5. S i g n i f i c a n c e and Use

5.1 Chemical analyses of l i q u i d s , s o l i d s , and gases f rom thevadose zone can provide in format ion on the presence, p o s s i b l esource, migration route, and phys i ca l-chemical behavior ofcontaminants. Remedial or m i t i g a t i n g measures can be formu-la t ed based on th i s in f o rmat i on . T h i s gu ide describes dev i c e sand procedure s that can be used to obtain vadose zone soilsampl e s .

5.2 Soil s a m p l i n g is u s e f u l for the reasons presented inSection 1. However, it should be recognized that the generalmethod is d e s t ruc t iv e , and that r e s a m p l i n g at an exact locationis not p o s s i b l e . T h e r e f o r e , if a l o n g term monitoring program isbeing de s igned , other methods for obtaining sample s should beconsidered.

6. Cri t er ia for S e l e c t i n g S o i l S a m p l e r s6.1 I m p o r t a n t criteria to cons ider when s e l e c t i n g dev i c e s for

vadose zone soil s a m p l i n g inc lude the f o l l o w i n g :6.1.1 T y p e of sample: An encased core s a m p l e , an uncased

core sample, a d e p t h - s p e c i f i c r epre s en ta t ive s a m p l e , or asample according to requirements of the analyse s ,

6.1.2 S a m p l e size requirements,6.1.3 S u i t a b i l i t y for s ampl ing various soil t y p e s ,6.1.4 Maximum s a m p l i n g d e p t h ,6.1.5 S u i t a b i l i t y for s a m p l i n g so i l s under various moisture

c o n d i t i o n s ,6.1.6 A b i l i t y to minimize cross contaminat ion,6.1.7 A c c e s s i b i l i t y to the s a m p l i n g s i t e , and6.1.8 Personnel requirements.6.2 The s a m p l i n g devices described in th i s gu ide have been

evaluated for these criteria. The r e su l t s are summarized in Fig.1.7. S a m p l i n g with H a n d Operated Devices

7.1 T h e s e devices , that have mo s t ly been d e v e l o p e d foragricul tural p u r p o s e s , inc lude:

7.1.1 S c r e w - t y p e augers,7.1.2 Barrel augers,7.1.3 T u b e - t y p e sampler s ,7.1.4 Hand held power augers, and7.1.5 Trench s a m p l i n g with shove l s in c o n j u n c t i o n with

machine excavations.7.2 The advantages of using hand operated devices over

dri l l rigs are the ease of equipment transport to l o ca t ions withpoor vehicle access, and the lower costs of s e t u p and decon-tamination. However, a major d i sadvantage is that thesedevices are l imi t ed to sha l lower d e p t h s than d r i l l rigs.

7.3 Screw-Type Augers:7.3.1 Description—The screw or s h i p auger is e s s e n t i a l l y a

small d i a m e t e r ( f o r e x a m p l e , 1.5 in. (3.81 cm)) wood augerf r om which the c u t t i n g s ide f l a n g e s and tip have been removed( I ) 5 (see F i g . 2 ( a ) ) . A c c o r d i n g t o t h e S o i l S u r v e y S t a f f (1), t h espiral part of the auger should be about 7 in. (18 cm) l ong , withthe di s tance s between f l i g h t s about the same as the diameter

5 The b o l d f a c e numbers in par en th e s e s r e f e r to the l i s t of re f erence s at the end ofthe text .

M o u S u O b i A r a u u S w x wOtontn unlSuU* O s e u K K i n biumn S J H t t m j f t o .5 W H M C o » T f f « S K n t v S a . 1 C c n f t t t r a S c J C o n n o n s SVM No Cat CoMm FM um«. WM a> rw. Y « N o'i. Sci l*»TM Or* S

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F I G . 1 C r i t e r i a f o r S e l e c t i n g S o i l S a m p l i n g E q u i p m e n t817

X:T:<S£v•—..-£':?:&:&&:.','' • • H O T i ^ S f e

D4700

( a ) S h i p A u g e r ( b ) Clo s ed AugerF I G . 2 Screw T y p e A u g e r s

(c) J a m a i c a OpenS p i r a l A u g e r

(for e x a m p l e , 1.5 in.) of the auger. T h i s f a c i l i t a t e s measuringthe d e p t h of penetration of the tool. Varia t ions on this d e s i gninclude the closed spiral auger and the Jamaica open spiralauger (2) (see Fig. 2(b) and Fig. l l ( c ) ) . The auger i s w e l d e donto a l e n g t h of sol id or tubular rod. The u p p e r end of this rodis threaded , to accept a handle or extension rods. As manyextensions are used as are required to reach the target s a m p l i n gdepth. The rod and the extensions are marked in even incre-ments (for e x a m p l e , in 6-in. (15.24-cm) increments) above thebase of the auger to aid in determining d r i l l i n g d e p t h . Awooden or metal hand l e fits into a t e e - t y p e c o u p l i n g , screwed

the uppermo s t ex t ens ion rod..3.2 Sampling Method—For d r i l l i n g , the auger is rotated

m a n u a l l y . The opera tor may have to a p p l y downward pressureto start and embed the auger; a f t e r w a r d s , the auger screws i t s e l finto the soil. The auger is advanced to its f u l l l eng th , and thenp u l l e d up and removed. S o i l f rom the d e ep e s t interval pen-etrated by the auger is retained on the auger f l i g h t s . A s a m p l ecan be c o l l e c t ed f rom the f l i g h t s using a spatula. A foo t pumpoperated h y d r a u l i c system has been d e v e l o p e d to advanceaugers up to 4.5 in. (11.43 cm) in diameter. T h i s largerdiameter a l l o w s insertion of other s a m p l i n g devices into thed r i l l hole , once the auger is removed, if desired (3).6

7.3.3 Comments—Samples obtained with screw-type sam-pl er s are d i s turbed and are not tru ly core sample s . T h e r e f o r e ,the s ampl e s are not s u i t ab l e for t e s t s requiring undis turbeds a m p l e s , such as hydrau l i c c onduc t iv i ty tests. In add i t i on , soilstructures are d i s rup t ed and small scale l i t ho l og i c f e a t u r e scannot be examined. N e v e r t h e l e s s , screw-type samplers ares t i l l suitable for use in co l l e c t ing samples for the purpose ofdetec t ing.contaminants . However, it is d i f f i c u l t to avoid trans-port ing shal low soil s downward when reentering a d r i l l hole.When representative sampl e s are desired from a discreteinterval, the borehole must be made large enough to insert asampler and extend it to the bottom of the borehole withoutt ou ch ing the s ide s of the borehole. It i s s ugge s t ed that a largerd i a m e t e r auger be used to advance and c lear the boreho l e , then

'"This re f erence is m a n u f a c t u r e r ' s l i t e r a t u r e , and it has not been s u b j e c t e d totechnical review.

a smal l er d iameter auger sampler be used to obtain the sample .S c r e w - t y p e augers work better in wet, cohesive so i l s than indry, loose soils. S a m p l i n g in very dry (for e xampl e , powdery)so i l s may not be p o s s i b l e with these augers as s o i l s wi l l not beretained on the auger f l i g h t s . A l s o , if the soil contains gravel orrock f r a g m e n t s larger than about one tenth of the hole d iameter ,d r i l l i n g may not be p o s s i b l e (4).

7.4 Barrel Augers:7.4.1 Description—The barrel auger consi s t s of a bit with

cut t ing edges w e l d e d to a short tube or barrel within which thesoil s a m p l e is re tained, we lded in turn to shanks. The shanksare w e l d e d to a threaded rod at the other end. Ext ens ion rodsare attached as required to reach the target s a m p l i n g d e p t h .Extens ions are marked in increments above the base of thetool. The uppermos t ex t ens ion rod contains a t e e - type c o u p l i n gfor a handle . The auger is ava i lab l e in carbon steel and s t a in l e s ssteel with hardened steel cu t t ing edge s (5, 6).

7.4.2 Sampling Method—The auger is r o ta t ed to advancethe barrel into the ground. The opera tor may have to a p p l ydownward pressure to keep the auger advancing. When thebarrel is f i l l e d , the unit is withdrawn from the soil cavity and asample may be c o l l e c t e d from the barrel.

7.4.3 Comments—Barrel augers g enera l ly prov ide largers a m p l e s than s crew-type augers. The augers can penetrateshallow c lays , s i l t s , and f i n e grained sands (7).6 The augers donot work wel l in grave l ly s o i l s , ca l i che , or s e m i - l i t h i f i e dd e p o s i t s . S a m p l e s obtained with barrel augers are d i s turb edand are not core sample s . T h e r e f o r e , the s ampl e s are notsui table for t e s t s requiring undi s turbed sample s , such ashydraulic conductivity tests. Never the l e s s , the samplers ares t i l l sui table for use in c o l l e c t i n g s ampl e s for the purpo s e ofde t e c t ing contaminants. Because the sample is retained insidethe barrel, there is l e s s of a chance of mix ing it with soil f r o ma sha l l ower interval during insertion or wi thdrawal of thesampler. The f o l l o w i n g are f i v e common barrel augers:

7.4.3.1 Pos t-ho l e augers (a l s o ca l l ed I w a n - t y p e augers),7.4.3.2 Dutch- type augers,7.4.3.3 Regular or general purpo s e barrel augers,7.4.3.4 S a n d augers, and7.4.3.5 Mud augers.

818

D47007.4.4 Post-Hole Augers—The most r ead i ly ava i lab l e barrel

auger is the p o s t - h o l e auger (al so ca l l ed the I w a n - t y p e auger)(8). As shown in Fig. 3, the barrel consi s t s of two-partc y l i n d r i c a l leaves rather than a c o m p l e t e c y l i n d e r and iss l i g h t l y tapered toward the cut t ing bit. The taper and thecupped bit h e l p to retain soils within the barrel. The barrel isavailable with a 3 to 12-in. (7.62 to 30.48-cm) diameter. Thereare two types of d r i l l i n g systems, one has a single rod andhandle, and the other has two handles. In s table, cohesive soils,the auger can be advanced up to 25 ft (7.62 m) (8).

7.4.5 Dutch-Type Augers—The Dutch-type auger (commer-c i a l l y deve loped by E i j k e l k a m p ) is a smaller variation of thepos t-hole auger design. As shown in F i g . 4, the pointed bit iscontinuous with two, narrow part-cylindrical barrel segments,welded onto the shanks. The barrel general ly has a 3 in. (7.62cm) out s ide diameter. T h i s tool is best suited for sampl ing wet,c layey soils .

7.4.6 Regular or General Purpose Barrel Augers—A ver-sion of the barrel auger commonly used by soil s c i ent i s t s andcounty agricul tural agents is d e p i c t e d in Fig. 5(a) and (b). Asshown, the barrel is a c o m p l e t e cyl inder. As with the po s t -ho l eauger, the c u t t i n g b l a d e s are cupped so that soil is loosened andforced into the barrel as the unit is rotated and pushed into theground. Each filling of the barrel corresponds to a d e p t h ofpenetration of 3 to 5 in. (7.62 to 12.70 cm) (1). The mostpopular barrel diameter is 3.5 in. (8.89 cm), but sizes rangingfrom 1.5 to 7 in. (3.81 to 17.78 cm) are available (6).6 Plas t i c ,s ta inle s s s t e e l , PTFE ( p o l y t e t r a f l u o r o e t h y l e n e ) or aluminumliners can also be used (6). 6 Extens ion rods are avai lable in 4ft (1.22 m) l ength s . The rods can be made from standard blackp i p e , from l igh twe igh t conduit or from seamless steel tubing.The extensions have evenly spaced marks to f a c i l i t a t e deter-mining s a m p l e d e p t h . The regular barrel auger i s s u i tab l e foruse in loam type soil s .

7.4.7 Sand Augers—For dry, sandy soi l s it may be neces-sary to use a variation of the regular barrel auger that includesa s p e c i a l l y - f o r m e d bit to retain the s a m p l e in the barrel (seeFig. 5 ( c ) ) . Sand augers with 2, 3, or 4-in. (5.08, 7.62, or10.16-cm) diameters are a v a i l a b l e (5).6

7.4.8 Mud Augers—Another variation on the regular barrelauger des ign i s a v a i l a b l e for s a m p l i n g wet, c layey so i l s . As

shown in Fig. 5(d~), the barrel is de s igned wi th open sides tof a c i l i t a t e extraction of sample s . The b i t s are the same as thoseused on the regular barrel auger (6).6 Mud augers with 2, 3 or4-in. (5.08, 7.62, or 10.16-cm) diameters are available (5).'6

7.5 Tube-Type Samplers:7.5.1 T u b e - t y p e samplers general ly have p r o p o r t i o n a l l y

smaller diameters and greater body l eng th s than those of barrelaugers.

7.5.2 For sampl ing , these units are perched into the soilcausing the tube to fill with material from the interval pen-etrated. The assembly is then p u l l e d to the surface and a samplecan be co l l e c t ed from the tube. Since the device is not ro ta t ed ,a nearly undisturbed sample can be obtained. Commercial unit sare available with f o o t lever a t ta chment s , a hydraul i c appara-tus, or drop-hammers to aid in driving the s a m p l e r into theground (5)6. Vibratory heads have also been d e v e l o p e d toadvance t ub e - type s ampl er s (9).6

7.5.3 T h e s e unit s are not as su i tab l e for s a m p l i n g in com-p a c t e d , g r a v e l l y s o i l s as are the barrel augers. T h e y arepre f erred if an undi s turbed s a m p l e is required. Commonly usedvarieties of the tube t y p e sampler s i n c l u d e :

7.5.3.1 Soi l s a m p l i n g tubes ( a l s o c a l l e d Lord s a m p l e r s ) ,7.5.3.2 Veihmeyer tubes ( a l s o c a l l e d K i n g tubes),7.5.3.3 T h i n - w a l l e d tube sampler s ( a l s o ca l l ed S h e l b y

tubes),7.5.3.4 Ring-lined barrel sampler s , and7.5.3.5 Piston samplers.7.5.4 Soil Sampling Tubes:7.5.4.1 Description—As d e p i c t e d in F i g . 6, the soil sam-

p l i n g tube consists of a hardened cu t t ing t i p , a cut-away barrel,and an uppermost threaded segment. The cut-away barrela l l ows textural examination and easy removal of soil sample s .Genera l ly , the tube is constructed f rom high s trength a l l o y steel(10).6 The samplers are avai lable with 6, 12, 15, 18, and 24-in.(15.24,30.48, 38.10,45.72, 60.96-cm) l e n g t h s ( 5 , 6 ) . The tubesare avai lab l e with 1.13 or 0.88-in. (2.87 or 2.22-cm) ou t s id ediameter. Two m o d i f i e d versions of the t ip are a v a i l a b l e , fors a m p l i n g in wet or dry so i l s . The s a m p l i n g tube is at tached toextension rods to a t ta in the target s a m p l i n g d e p t h . A cross-handle is attached to the uppermos t rod. Extens ion rods aremade of l i g h t w e i g h t , durable metal. T h e y are ava i lab l e in a

H a n d l e

BitF I G . 3 P o s t - H o l e T y p e Barrel A u g e r

819

D4700

F I G . 4 Dutch T y p e AugerK i n d l e

- S h a n k-Barrel

Cutt ing Bit(a) Regular Barrel Auger

(b) Regu lar (c) Sand Auger (d) Mud A u g e rBarrel AugerFIG. 5 Barrel A u g e r V a r i a t i o n s and Soi l Mois ture

variety of lengths depending on the manufacturer. Markings onthe extensions and the sampler f a c i l i t a t e determining sampled e p t h s .7.5.4.2 Sampling Method—The sampler is pushed into theground by leaning on the unit's handle. Once the sampler hasreached the bottom of the sampl ing interval, it is twisted to

break soil continuity at the tip. Depending on the type ofc u t t i n g edge, the tube sampler may obtain samples varying indiameter from 0.69 to 0.75 in. (1.75 to 1.91 cm).7.5.4.3 Comments—The soil sampl ing tube works best inclayey, cohesive soils. If the soil contains cobbles or rocknents larger than about one-half the cutting tip diameter,s a t i s f a c t o r y sampling may not be po s s ib l e . If the soil iscohesionless, it will not be retained in the tube. With time, the

cutting tip will be damaged and worn dull . Most units aredesigned so that this part can be replaced.7.5.5 Veihmeyer Tubes:7.5.5.1 Description—The Veihmeyer tube is a long, com-p l e t e cylinder. As shown in Fig. 6, this unit consists of abevel led tip, that is threaded into the lower end of the tube, anda drive head threaded onto the upper end of the tube. Toesampler is constructed of hardened steel. The tube is generallymarked in even increments (for e xampl e , 1 ft or 0.30 m). Thesesamplers are available in 4 to 16-ft (1.22 to 4.88-m) leng* s

with a 0.75-in. (1.91-cm) inside diameter.7.5.5.2 Sampling Method—The lower guide rod of the drophammer is s l i p p e d into the upper tube, through the drive beao(see F i g . 7). The hammer is used to pound the sampler into to6

ground. Thon the harSamples ai. 7.5.5.3 (w sometimHowever, ti*ould be c*iH cause

I General ly bt

820

D4700

Cut-away' B a r r e l

' • « — C u t t i n g T i pF I G . 6 S o i l S a m p l i n g T u b eI DriveHammer

-Tube

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tube. Thes generallyi m). Thesem) l e n g t h sD! JPdrive neadler into the

. C u t t i n gT i pF I G . 7 Veihmeyer Tube

ground. The sampler is then retrieved by p u l l i n g or j erking up"on the hammer to force the sampler out of the soil cavity.

S a m p l e s are extruded by f o r c ing a rod through the tube.7.5.5.3 Comments—Prior to sampling, the inside of the tube

is sometimes coated with a lubricant to f a c i l i t a t e extrusion.However, the types of analyses to be performed on the samplesshould be considered to determine if the presence of lubricantwill cause interference. Because the Veihmeyer sampler is as o l i d - w a l l e d tube and is f i t t e d with a drop hammer, it cang e n e r a l l y be used in more resis tant so i l s than the soil s ampl ingtube.

7.5.6 Thin-Walled Tube Samplers:7.5.6.1 Description—Thin-walled tube ( S h e l b y T u b e ) sam-

p l e r s are readily avai lab l e with 2, 3, and 5-in. (5.08, 7.62, and12.70-cm) outside diameters and are commonly 30 in. (76.20cm) long. The 3 by 30-in. (7.62 by 76.20-cm) out s ide d iameterlong sampler is most common. The advancing end of thesampler is ro l l ed inwardly and has a c u t t i n g edge with a s m a l l e rdiameter than the tube inside diameter. The cutting edge insidediameter reduction, denned as a "clearance ratio," is u sua l ly inthe range of 0.0050 to 0.0150 or 0.50 to 1.50% ( R e f e r toPractice D 1587). The s a m p l e r tube is u s u a l l y connected with

821

D4700set screws to a sampler head that in turn is threaded to connectw ' f h extension rods. P l a s t i c a n d P T F E seal ing caps f o r u s e a f t e r

'ng are r ead i ly a v a i l a b l e for the 2, 3, and 5-in. (5.08,and 12.70-cm) diameter tubes ( r e f e r to Practice D 4220).

S h e l b y tubes are commonly ava i lab l e in carbon steel but can bemanufactured f r o m other metal (see Fig. 8).

7.5.6.2 Sampling Method—The S h e l b y tube is pushed intosoil by hand, with a j a ck- l i k e system or with a hydrau l i c pi s ton.The sample recovered is o f t e n l e s s than the dis tance p u s h e d ,that is, the recovery ratio is less than 1.0. The recovery ratio isl e s s than 1.0 because of soil compaction during sampl ing , andbecause f r i c t i o n between soil and the inner tube wa l l s becomesgreater than the shear s trength of the soil in f ron t of the tube.Consequent ly , soil in front of the advancing end of the tube isd i s p l a c e d l a t e r a l l y rather than entering the tube (11). In general,shorter tubes p r o v i d e l e s s -d i s t urb ed s a m p l e s than longer tubes.S a m p l e s are e x t r u d e d from the S h e l b y tube with a h y d r a u l i cram. As with all s a m p l i n g d ev i c e s , the most d i s turb ed port ionof the sample in contact with the tube is considered unrepre-sentative. W i l s o n et al. (12) d e v e l o p e d a paring device toremove this outer layer of the core during extrusion.

7.5.6.3 Comments—Shelby tubes are best used in c l a y s ,s i l t s , and f i n e - g r a i n e d sands. If the s o i l s are cohe s i onl e s s , theymay not be retained in the tube. If f i rm to very hard soi l s areencountered, dr iv ing (hammering) the sampl er may be re-quired. However , this should be avoided as the tube maybuckle under the drive stress.

7.5.7 Ring-Lined Barrel Samplers:7.5.7.1 Description—As described in Practice D 3550, the

'ined barrel sampl er cons i s t s of a one piece barrel or twojarrel halve s , a drive shoe, rings, and a sampler head (see

Fig. 9). The rings, that are u s u a l l y brass, f i t snug ly inside thebarrel and are des igned to be d i r e c t l y inserted into geotechnicalt e s t i n g a p p a r a t u s e s when removed f r o m the barrel. Mostsampler s are de s igned to hold at least two rings. The barrel iscommonly 3.5 in. (8.89 cm) inside d iamet er and 3.94 to 5.91in. (10 to 15 cm) long (5). 6 W i t h these l eng th s , the barrel canbe f i t t e d with a varie ty of l iners ranging in l e n g t h f r o m 1 to

2.36 in. (2.54 to 6 cm).7.5.7.2 Sampling Method—The ring-l ined barrel s a m p l e r

can be driven or pushed into soil. Once re tr i eved, the s a m p l e ris d i s a s s emb l ed , and the s a m p l e - f i l l e d rings are removed. Therings are u s u a l l y removed as one unit and p l a c e d into a cappedcontainer. A l t e r n a t e l y , the i n d i v i d u a l s o i l - f i l l e d rings can becapped with p l a s t i c or PTFE and then sealed with wax oradhesive tape (re f er to Pract ice D 4220).

7.5.7.3 Comments—Because barrel sampler s are more rigidthan th in-wal l ed tubes, they can be driven into hard s o i l s andsoils containing sands and grave l s that might damage thin-walled tubes. The sampler prov id e s s a m p l e s in rings which canbe handl ed without f u r t h e r disturbance of me soil. Because oft h i s , these devices are most o f t e n used when geotechnical orchemical analyses are to be p er f ormed .

7.5.8 Piston Samplers:7.5.8.1 Description—Locally saturated (for e x a m p l e , by

perched ground water), or cohe s i onl e s s s o i l s , and very s o f ts o i l s or s l udge s may not be retained in most sampler s , evenwhen f i t t e d with retainer baskets or f lap valves. Pi s t on sampler scan be used in these si tuations. The sampl er cons i s t s of as a m p l i n g tube, extension p i p e attached to the tube, an internalpis ton, and rods connected to the p i s t on and running throughthe extension p i p e (see Fig. 10). T h e s e s ampl er s are o f t e n b u i l t ,as needed, out of common PVC ( f o r use in s l u d g e ) or steel p i p ef i t t i n g s . The s a m p l i n g tube commonly has a 0.75 to 3-in. (1.91to 7.62-cm) ins ide d iameter and is 8 in. to 9 ft (20.32 cm to2.74 m) long (13). A variation d e s i gned for s a m p l i n g peat hasa cone shaped p i s t on (8).

7.5.8.2 Sampling Method—The sampler can be pushed intothe ground with the handle or driven into the ground with adrop hammer (13). As the tube is advanced, the p i s t on is helds tationary or p u l l e d upward with the attached rods. Once thetube has been advanced through the s a m p l i n g in t e rva l , it isrotated to break suction that might have deve l oped between thesoil and the ou t s ide wall of the tube. The s ampl er is then p u l l e dto the surface k e e p i n g the p i s t on rod f i x e d with respect to theextension p i p e . The s a m p l e is retained because of suction that

S a m p l e r' H e a d

-Ball Valve-Screw

T h i n - w a l l e d" T u b e

••— C u t t i n g EndF I G . 8 T h i n - W a l l e d T u b e S a m p l e r

822

rel -

to a cappedngs can beith wax ormore rigid

d s o i l s andnage thin-which can

3ecause ofchnical or

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D4700

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RingUners- Drive Shoe• Cut t ing T i p

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•Rod

Frame H a n d l e

Extension' P i p e

— Tube

Q Piston 9FIG. 10 H a n d Operated Piston S a m p l e r

d e v e l o p s between the p i s t on and the sample. Upon retrieval,the sample is extruded byusing the p i s t on to force the sampleout of the tube. Sharma and De Dalta (14) described acyl indrical s a m p l e r for use in p u d d l e d soils that would f l o wback out of most samplers. The design includes a basal shutterthat retains the sample while the sampler is withdrawn from thesoil.

7.5.8.3 Comments—Because the sampler depends on devel-opment of suction between the sample and the piston, it maynot work in unsaturated, coarse-grained sands and gravels. T h i sis due to the high air permeabil i ty of such material thatprevents the creation of high suction.

7.6 Hand Held Power Augers:7.6.1 Description—A very s imple , commercially available

auger consi s t s of a solid f l i g h t auger attached to and driven by

a small air-cooled engine (see Fig. 11). Two handle s on thehead assembly allow two operators to guide the auger into thesoil. T h r o t t l e and clutch controls are integrated into grips on thehandles. Augers are available with diameters ranging f rom 2 to16 in. (5.08 to 40.64 cm). The auger sections are commonly 3

ft (0.91 m) long.7.6.2 Sampling Method—As the auger rotates into so i l ,

cu t t ing s advance up the f l i g h t s and are discharged at thesurface. Soil samples can be col lec ted from the surfacedischarge, or from the auger f l i g h t s a f t e r p u l l i n g the auger outof the ground. Alternat ive ly, samples can be co l l e c t ed withother samplers ( f o r example, a th in-wal led tube) a f t e r augerremoval.

7.6.3 Comments—As discussed in 7.3, if samples are col-lected from surface discharge or from the n igh t s , they are

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F I G . 1 1 H a n d H e l d Power A u g e r

disturbed and are not suitable for some uses. In addi t ion, ifsamples are c o l l e c t ed f rom surface di scharge, it is d i f f i c u l t todetermine the d e p t h f rom which the soil came and uncontrolledmixing of soil from d i f f e r e n t d e p t h intervals can occur. Theauger operates well in most soils. However, if the soil iscohesionless , it may not be retained on the f l i g h t s and s a m p l i n gin that f a s h i o n may not be p o s s i b l e . If the soil contains cobblesor b o u l d e r s , d r i l l i n g may not be p o s s i b l e . If the auger "hangsup'" on an obstruction, the machine will start to rotate at thesurface. Otherwise, the operator should not attempt to s t oprotation of the machine by grabbing the handles . An alternatede s ign that t rans f er s the torque to a separate engine preventsthis problem (15).6 As previously stated, it is prudent toperform the f i e l d work with at least two peopl e present.

i.l Trench Sampling:1.1.\ Description—Soils may be sampled from a trench or

pit excavated for that purpose . Excavation is usual ly performedby a backhoe, and samples are collected with knives, trowels,or shovels. Occasionally, sample s are co l l e c t ed f r o m the s idesor the bottom of the trench or pit with hand augers or tube-typesampler s .

7.7.2 Sampling Method—Excavation is performed underthe guidance of the sampl ing technician. S a m p l i n g is per-formed only a f t e r the backhoe has moved away from the trenchor pit. When the trench or pit is in unstable material or is morethan a few f e e t deep, the sampl ing technician should only enterthe trench or pit a f t e r it has been shored up or the s i d e w a l l shave been cut back to within the angle of repose (seeOccupational S a f e t y and H e a l t h A d m i n i s t r a t i o n regulat ions).Otherwise, samples are more commonly collected at thesurface from the bucket of the backhoe as excavation occurs.

7.7.3 Comments—The maximum s a m p l i n g d e p t h for thetrench or pit method is dic tated by the reach of the backhoe, thesoil type and the moisture content of the soil. Maximum d e p t h sof up to 20 ft (6.10 m) can be obtained in moist clays.Maximum d e p t h s of le s s than 10 ft (3.05 m) are common in drysands. S a m p l e s c o l l e c t ed from the backhoe bucket should betaken from the center of the material to prevent collecting soilcontaminated by the bucket surface, and to prevent inclusion ofmaterials that may have f a l l e n from above the desired sampl ing'nterval. However, when this is done, it is d i f f i c u l t to accurately

>timate the depth from which the sample was obtained.Trenches are useful for obtaining l i t h o l o g i c information sincecross sections of the vadose zone can be s tudied and photo-

graphed. Trench or pit sampling is o f t e n used in areas withdifficult access since backhoes are designed to travel on roughterrain. However , because the process involves excavating amuch larger hole than dr i l l ing methods , chances of encounter-ing underground ut i l i t i e s are increased, and proper b a c k f i l l i n gand compaction of the trench is o f t e n very d i f f i c u l t .8. M u l t i p u r p o s e and Auger Drill Rigs

8.1 Vadose zone samplers used in conjunction with dril l rigsare identical to those used to sample below the water table.However, commonly used dri l l rigs such as cable tool androtary units are not recommended as they g e n e r a l l y require theintroduction of d r i l l i n g f l u i d s to the soils to be sampled. Airrotary dri l l ing is also undesirable for obtaining samples forpore l iquid or gas extraction. In most cases, ho l low-s t emaugers with some type of cy l indr i ca l sampler prov ide thegreatest level of assurance that soil sampled within the vadosezone was not carried downward by the dr i l l ing or samplingprocess. For some s i tuations, such as s a m p l i n g f i r m to veryhard ground, using m u l t i p u r p o s e auger-core-rotary dri l l rigswill be necessary. For some geo l og i c circumstances the use ofsolid stem augers will provide an adequate d r i l l i n g method.

8.2 Multipurpose Auger-Core-Rotary Drill Rigs:8.2.1 M u l t i p u r p o s e auger-core-rotary d r i l l rigs are g enera l ly

equipped with rotary power and vertical f e e d control toadvance both hollow-stem augers and continuous f l i g h t (solidstem) augers to d e p t h s greater than 100 ft (30.48 m). T h e s esame d r i l l s have secondary c a p a b i l i t y for rotary and cored r i l l i n g . The larger of these d r i l l s are t y p i c a l l y mounted on20000 to 30000-lb (9070 to 13605-kg) GVW trucks. Thesame mul t ipurpo s e d r i l l rigs are available on both rubber-tiredand track-driven all-terrain carriers. The smal l er of the mul t i-purpose d r i l l s are t y p i c a l l y mounted on trailers or one-ton, 4 by4 trucks.

8.2.2 When equipped with augers, the sampling process isidentical to that for auger dri l l rigs. When m u l t i p u r p o s eauger-core-rotary drill rigs or auger dril l rigs are used, thespeed of dr i l l ing and sampling is much greater than with handoperated equipment. There for e it is use ful to have a larger crewto e f f i c i e n t l y handle , l og , i d e n t i f y , and preserve the samples . •

8.3 Auger Drill Rigs—Auger dri l l rigs are similar to multi-purpose auger-core-rotary drill rigs. T h e y are manufactureds p e c i f i c a l l y for e f f i c i e n t auger dr i l l ing but do not have thepumps and hoists that are required for e f f i c i e n t core or rotary

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ireas with: on rough;avating aencounter-b a c k f i l l i n g

h d r i l l rigsater table.; tool and•equire then p l e d . Air.mp" r.Ik i•oviae the:he vadose

s a m p l i n gm to very

drill rigsthe use ofmethod.

; general lycontrol toight ( s o l i dm). T h e s e

and coreounted on•ucks. Theabber-tiredthe mult i-

e-ton, 4 byprocess isi l t i p u r p o s eused, the

with handarger crew

S3"

have theor rotary

d r i l l i n g . The rigs can be equ ipped with either sol id stem orh o l l o w stem augers. There are r e la t ive ly few auger d r i l l savailable in comparison to mult ipurpose auger-core-rotarydr i l l s .9. Auger D r i l l i n g and S a m p l i n g

9.1 Solid Stem Auger Drilling and Sampling:9.1.1 Description—The tools used for so l id- s t em auger

d r i l l i n g include: auger sections, the drive cap, and the cutterhead (see F i g . 12). Auger sections are t y p i c a l l y 5 ft (1.52 m)l o n g and are in t e r changeab l e for as s embly in an art i culated butcont inuous ly f l i g h t e d column. Augers are available in diam-eters up to 24 in. (60.96 cm). The cutter head is attached to thelowermost or l ead ing f l i g h t of the auger column. It is about 0.5in. (1.25 cm) larger in diameter than the f l i g h t s . Head type sinclude f i s h tail or drag bits for use in cohesionless material s ,and clay or stinger bi t s for use in more consol idated material(16).

9.1.2 Sampling Method—As the auger column is rotatedinto s o i l , c u t t i n g s are retained on the f l i g h t s . The augers arethen removed f rom the hole and sample s are taken f r o m theretained soil. S a m p l e s obtained with solid stem augers aredis turbed and are not core samples. T h e r e f o r e , the sample s arenot su i tab l e for analyses requiring undisturbed samples , suchas h y d r a u l i c conduc t iv i ty tests. T h i s sampling method canprov ide an adequa t e ly clean borehole in some clayey and s i l t ysoils. However, when using the method in caving or squeezingground, the qual i ty and the origin of the recovered samples arequestionable because soi l s f r o m d i f f e r e n t intervals may havemixed. T h e r e f o r e , when representative samples f rom discreted e p t h s are des ired, the borehole should be made large enoughto insert a smaller diameter auger or another sampler (forexample , a t h in-wa l l ed tube) to the bottom of the borehole,without touching me s ide s of the borehole (see F i g . 1 1 ) , tocollect a discrete sample from the interval ahead.

9.1.3 Comments—Typical d r i l l i n g d e p t h s with sol id stemaugers range f r o m 50 to 120 ft (15.24 to 36.58 m). The greaterd r i l l i n g d e p t h s are attained in f i r m , s i l t y and clayey soil s .However, the d e p t h to which the hole will remain open fors a m p l i n g once the auger column has been removed is u sual lyless than the maximum d r i l l i n g d ep th . If cascading water or

ContinuousF l i g h t AugersGroundS u r f a c e

CohesiveSoil .3

cohes ionles s so i l s are encountered, it can be expec ted that thehole wil l cave at that d e p t h . The sample d e p t h measurement, astaken from its location on an auger, is not precise. T h i s isbecause soil may move up the f l i g h t s in an uneven f a s h i o n asthe auger column is advanced. As with ho l low-s t em augers,solid stem augers are o f t e n painted by the dri l l er or manufac-turer. It is prudent to remove thi s paint b e f o r e d r i l l i n g . Themajor i ty of the paint can be removed by d r i l l i n g through sandysoil s or by sand blas t ing. As with all sampl ing devices,decontamination (for e xampl e , steam cleaning) should beper formed between holes when chemical analyses are to beper formed on the sample s . T h i s is e s p e c i a l l y important with theso l id stem auger as it double s as the d r i l l i n g and s a m p l i n g tool.

9.2 Bucket Auger Drilling and Sampling:9.2.1 Description—The bucket auger is a large diameter

cylindrical bucket with auger-type cutt ing b lades on the bot-tom. The bucket can have a diameter ranging from 12 in.(30.48 cm) up to 6 ft (1.83 m) with l e n g t h s varying f rom 24 to48 in. (60.96 to 121.92 cm) (17). The bottom is hinged to allowcuttings to be empt i ed out (see F i g . 13).

9.2.2 Sampling Method—The bucket is rotated to d e p t h inthe vadose zone until the bucket is f u l l . There f or e , dependingon the bucket l eng th , s a m p l i n g intervals can range from 24 to48 in. (60.96 to 121.92 cm). S a m p l i n g consists of extractingsmall diameter core sampl e s f rom the interior of the bucketaf t er lowering the f u l l bucket to the ground (see S e c t i o n 7).T h i s approach minimizes problems with undi s cre t e mixing ofdiscrete portions to be sampled.

9.2.3 Comments—The bucket auger is best suited for sam-p l i n g from r e l a t i v e l y s table clays as the caving prob l emsdiscussed in 9.1.3 are a m p l i f i e d by the larger hole diameter.Boulders can impede dr i l l ing and may have to be i n d i v i d u a l l yremoved from the hole b e f or e s a m p l i n g can continue (IS) 6 .Genera l ly , b ou ld e r s up to one-third or one-fourth the bucketdiameter can be picked up by the bucket. Common samplingd e p t h s are l e s s than 50 ft (15.24 m) but hole s up to 250 ft(76.20 m) deep have been d r i l l e d (16, 17).

9.3 Hollow Stem Auger Drilling and Sampling:9.3.1 Description—Outer components of the ho l l ow stem

auger system include: ho l l ow auger sections, the h o l l o w augerhead, and the drive cap. Inner components inc lude: the p i l o t

S p l i t Barrelor thin-walledT u b e S a m p l e rW - ' 1

A u g e r — *

C u t t i n g ''•'F I G . 1 2 S o l i d S t e m A u g e r S a m p l i n g

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D4700

K e l l yD u m p i n gArm

i Bucket1 A u g e r

F I G . 1 3 Bucket A u g e r a n d D r i l l i n g R i g

assembly, the center rod column, and the rod-to-cap a d a p t o r(see F i g . 14). The auger head contains replaceable carbide teeththat p u l v e r i z e the format ion during f l i g h t column rotation. The

ig d iameter is somewhat greater than the f l i g h t i n g diam-because of the pro t rud ing teeth. A u g e r sections are

t y p i c a l l y 5 ft (1.52 m) long and are interchangeable forassembly in an articulated but continuously f l i g h t e d column.D r i l l i n g progre s s e s in 5 ft (1.52 m) or shorter increments and

s ampl ing can be accompl i shed at any d e p t h within thatincrement. Upon advancement of a 5 ft (1.52 m) increment,another 5 ft (1 .52 m) section of ho l low-s t em auger and centerrod is a d d e d . H o l l o w - s t e m augers are r e a d i l y a v a i l a b l e with2.25,2.75,3.25,3.75, 4.25, 6.25, and 8.25-in. (5.72, 6.99,8.26,9.53, 10.80, 15.88, and 20.96-cm) inside diameters.

9.3.2 Sampling Method—The auger column and p i l o t as-s embly are advanced to the top of the desired s a m p l i n g

Drive Cap -Rod to CapA d a p t e rAuger Connector

„_ H o l l o w StemA u g e r Sec t i on

F T - — — Center Rod

— P i l o t A s s e m b l yB*— A u g e r Connector

— Replaceab l eCarbideAuger T o o t hAuger H e a d -

Center H e a d -F I G . 1 4 H o l l o w - S t e m A u g e r C o m p o n e n t s

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thin thaticrement,nd•ab..99, 8.26,p i l o t as-

s a m p l i n g

interval. S a m p l i n g is a c compl i shed by removing the p i l o tas sembly and center rod, if they are used, and inserting thesampler through the h o l l o w stem of the auger column (see Fig.15). The sampler may be lowered to the sampling d e p t h byattaching it to center rods or by using a wireline assembly (12).When the sampler is attached to center rods, a sample isc o l l e c t e d by p u s h i n g or driving the sampler into undisturbedsoil with the rig hydraulic system or with a drop hammer.When a wire l ine is used, the sampler is locked into p l a c e aheadof the lower-most auger and advanced into the s a m p l i n ginterval by rotating the auger column (18).6 H o l l o w stemaugers with a 6.25-in. (15.88-cm) inside diameter a l l o w the useof 5-in. (12.70-cm) ou t s id e diameter S h e l b y tubes and 4.5-in.(11.43-cm) outside diameter sp l i t barrel samplers (see 9.4).

9.3.3 Comments—The purpose of the center head ( p i l o t )assembly is to prevent soil s f r o m entering the auger column asit is advanced (19). Drisco l l (17) sugge s t s that the a s s emblymay be omitted when d r i l l i n g through hard, s i l ty and clayeyso i l s as these material s will u s u a l l y form a 2 to 4 in. (5.08 to10.16 cm) long p l u g at the auger opening. However, Hacke t t(19) recommends that the p i l o t assembly be used when d e t a i l e dsample s are required. When perched water is encountered,"heaving sands" that move up into the auger column upon p i l o tassembly removal during s a m p l i n g , may be a concern. Variousone-way p l u g s that allow sampling, but that prevent sand frommoving into the auger column, are described in Hacke t t (19).The important c a p a b i l i t y of being able to obtain samples thatdo not contain mixed material from shal low sources in the holeis enhanced by using the ho l low-s t em auger method. However,because the sections are hol low, decontamination of the augerinteriors between holes to prevent cross contamination isd i f f i c u l t . H i g h pressure steam cleaners are usual ly necessary toremove caked-on s o i l s and contaminant s . H o l l o w stem augersmay advance r a p i d l y through u n c o n s o l i d a t e d mater ia l s .

9.4 Sampling Devices:9.4.1 S a m p l i n g device s used in c o n j u n c t i o n with h o l l o w

stem augers and o c c a s i o n a l l y in hole s advanced by sol id stemaugers inc lude:

9.4.1.1 T h i n - w a l l e d tube sampler s (also ca l l ed S h e l b ytub e s) ,

9.4.1.2 S p l i t - b a r r e l dr ive s a m p l e r s ( a l s o c a l l e d S p l i tspoons),

9.4.1.3 Ring- l in ed barrel s ampl er s ,9.4.1.4 Continuous s a m p l e tube sys t ems, and

9.4.1.5 Piston samplers.9.4.2 Thes e s ampl e r s are either pushed or driven in se-

quence with an increment of d r i l l i n g or advanced s imu l ta-neously with the advance of a hollow stem auger column.

9.4.3 Thin-Walled Tube Samplers:9.4.3.1 Description—The th in-wa l l ed tube sampl er cons i s t s

of a tube connected to a head with screws. The head is threadedto connect with standard dril l rods. The head contains a b a l lcheck valve. T h i n - w a l l e d tube ( S h e l b y tube) samplers arereadi ly avai lab l e with 2 ,3 , and 5-in. (5.08,7.62, and 12.70-cm)outside diameter and are commonly 30 in. (76.20 cm) long.The 3 by 30 in. (7.62 by 76.20 cm) out s ide diameter l o n gsampler is most common. The advancing end of the s ampl er isconstructed with an inward l i p , machined to a cutting edge, thathas a smaller diameter than the tube inside diameter. Thecutting edge inside diameter reduction, d e f i n e d as a "clearanceratio," is u s u a l l y in the range of 0.0050 to 0.0150 or 0.50 to1.50 % (refer to Practice D 1587). PTFE or p la s t i c sealing capsand other sealing devices for use a f t e r s a m p l i n g are r e a d i l yavai lable for the 2, 3, and 5-in. (5.08, 7.62 and 12.70-cm)diameter tubes ( r e f e r to Practice D 4220). S h e l b y tubes arecommonly available in carbon steel but can be manufacturedf r om other metal (see Fig. 8).

9.4.3.2 Sampling Methods—When a S h e l b y tube is pushedinto soil, the length of the sample recovered is o f t e n less thanthe dis tance p u s h e d , that is, the recovery ratio is l e s s than 1.0(see 7.5.6.2). In add i t i on , a por t ion of the sample f r e q u e n t l yremains in the borehole a f t e r retrieval of the sampler. T h i s isdue to suction that d e v e l o p s at the sampler-soi l in t er fa c e . T h i ssuction may be broken by twi s t ing the sampler prior to retrievalor by advancing the auger column below the base of thesampler before retrieval (20). S a m p l e s are extruded from theS h e l b y tube with a h y d r a u l i c ram. As with al l s a m p l i n gdevice s , the port ion of the s a m p l e in contact with the tube isconsidered d i s turbed and unrepresentative. W i l s o n et al. ( 1 2 )d e v e l o p e d a paring device to remove this outer layer of the coreduring extrusion.

9.4.3.3 Comments—The ball check valve was o r i g i n a l l yintended to provide a vent for d r i l l i n g f l u i d s when p u s h i n g thetube into s o i l , and also to prevent the column of f l u i d wi thin thedri l l stem from f o r c ing the sample out of the tube duringretrieval. Since d r i l l i n g f l u i d s are not used when s a m p l i n g inthe vadose zone, these cons iderat ions are not impor tant .However, the valve does p r o v i d e a vent for air d i s p l a c e d as the

A u g e r /.C o l u m n 1? ^Center $ .Hod 7? ~

P i l o t .,A s s e m b l y ~g.

Open Axisof AugerColumn iW i t h Pilo t •A s s e m b l y :and Center /4R o d fRemoved -3i-

xvJ•W.rit>

S a m p l i n g _

S p l i t ; ,Barrel o r V jT h i n - w a l l e d ' 5 ,Tube S a m p l e r -f -

F I G . 1 5 H o l l o w - S t e m A u g e r S a m p l i n g827

D4700sampler is pushed into soil. She lby tubes are best used in clays,s i l t s , and f i n e grained sands. T h e y can be pushed with the

iulic system of most dri l l rigs in f in e grained sands that are, to moderately consol idated or in clays and s i l t s that are

s o f t to f irm. If the soils are cohesionless, they may not beretained in the tube. If consol idated or hard s o i l s are encoun-tered, driving the sampler may be required. However, sometubes may buckle under the drive stress. A spr ing-loaded barrelhas been d e v e l o p e d to protec t the S h e l b y tube from bucklingwhen s a m p l i n g these so i l s (21).6

9.4.4 Split-Barrel Drive Samplers:9.4.4.1 Description—The spli t-barrel drive sampler consists

of two spl i t-barrel halves , a drive shoe, and a sampler headcontaining a ball check valve, all of which are threadedtogether (see Fig. 15). The most common size has a 2-in.(5.08-cm) ou t s i d e diameter and a 1.5-in. (3.81-cm) insidediameter s p l i t barrel with a 1.375-in. (3.49-cm) ins ide diameterdrive shoe. T h i s sampler is used ex t ens ive ly in geotechnicalexp lora t ion (Ref er to Method D 1586), When f i t t e d with a 16gage liner for encased cores, the sampler has a 1.375-in.(3.49-cm) inside diameter throughout, -in. (7.62-cm) outsidediameter by 2.5-in. (6.35-cm) inside diameter split-barrelsampl er with a 2.375-in. (6.03-cm) inside diameter drive shoeis also avai lab l e (22). 6 Other spl i t-barrel samplers in the sizerange of 2.5-in. (6.35-cm) to 4.5-in. (11.43-cm) outside diam-eter are manufactured but are less common. A p l a s t i c or metalretainer basket, or a flap valve is o f t e n f i t t e d into the drive shoeto prevent sample s from f a l l i n g out during r e t r i eva l .Fig . 16

9.4.4.2 Sampling Method—As described in Method D 1586"ampler is threaded onto d r i l l i n g rods and is lowered to the

/m of the boring. The sampler is then driven into the soilwitn blows from a drop hammer attached to the dri l l rig. Thehammer u s u a l l y weighs 140 Ib and is operated by the driller.The s a m p l e r is extracted from the soil in a manner that wil lensure maximum sample recovery. A s a m p l e is obtained by

disassembling the drive shoe and head, and s p l i t t i n g the barrelto expose the core of soil. Material dis turbed by contact withthe barrel can be scraped away, or a l e s s d i s turbed interiorportion co l l e c t ed with a spatula.

9.4.4.3 Comments—Split barrel drive samplers can be usedin all soil type s if the larger grain sizes can enter through theopening of the drive shoe. Because the sampler can be f i t t e dwith a retainer basket, it is t y p i c a l l y used in p l a c e of thin-wal l ed tubes when cohesionles s so i l s are to be sampled .

9.4.5 Ring-Lined Barrel Samplers:9.4.5.1 Description—As described in Practice D 3550, the

ring-lined barrel sampler consists of a one piece barrel or twospl i t-barrel halves, a drive shoe, rings, a waste barrel and asampler head containing a ball check valve (see F i g . 17). Therings fit snugly inside the barrel and are de s igned to be d i r e c t l yinserted into geotechnical t e s t ing apparatus when removedf r o m the barrel. Most sampler s are d e s igned to hold at least sixrings. The waste barrel provide s a space above the rings intowhich disturbed soi l , o r ig ina l ly at the bottom of the ho l e , canmove. The samplers are commonly available with 2, 3, and4-in. (5.08, 7.62, and 10.16-cm) outside diameter.

9.4.5.2 Sampling Method—The ring-lined barrel samplercan be driven or pushed into soil. It is important to insert thesampler de ep enough to al low all disturbed soil to movethrough the rings and into the waste barrel. Once retrieved, thesampler is d i s a s s emb l ed , and the sample f i l l e d rings arec a r e f u l l y removed. The rings are u s u a l l y removed as one unitand placed into a capped container. A l t e r n a t e l y , the i n d i v i d u a lsoil f i l l e d rings can be capped with p l a s t i c or PTFE and evensealed with wax or adhesive tape (re f er to Practice D 4220).

9.4.5.3 Comments—Because ring-l ined barrel samplers aremore rigid than thin-wal led tubes, they can be driven into soi l scontaining sands and gravels that might damage th in-wal l edtubes. The sampl er prov ide s s ampl e s in rings that can behandled without f ur th e r disturbance of the soil. Because of th i s ,

S a m p l e r' H e a dBall V a l v e

-Barrel

Spacer f o rRetainer- Placement-Drive Shoe- C u t t i n g T i p

F I G . 1 6 S p l i t - B a r r e l Drive S a m p l e r828

Cut t ingT i p

D4700S l i o e R l n g U n e r s Check fEac^ f —— - ^ ——— ^ V a l v e |

" PS a m p l e rBarrel WasteBarrel

F I G . 1 7 R i n g - L i n e d Barrel S a m p l e r

these devices are most o f t e n used when geotechnical orchemical analyses are to be per formed.

9.4.6 Continuous Sample Tube System:9.4.6.1 Description—Continuous sample tube systems that

fit w i th in a ho l l ow- s t em auger column are r eadi ly available inN o r t h America. The barrel is t y p i c a l l y 5 ft (1.52 m) long, andfits within the lead auger of the ho l l ow auger column. Thesampler is prevented f rom ro ta t ing as the auger column isturned (20). For many conditions the sampler provides con-tinuous, 5 - f t (1.52-m) sample s (see Fig. 18). The as sembly canbe s p l i t - or solid-barrel and can be used with or without linersof various m e t a l l i c and nonme ta l l i c materials (20). Two clear,p l a s t i c , 30 in. (76.20 cm) long liners are o f t e n used. Thesampler may also be f i t t e d with a p l a s t i c or metal retainerbasket, or a f a l p valve to prevent cohesionles s soils fromf a l l i n g out of the sampler during retrieval (20).

9.4.6.2 Sampling Method—The sampl er is locked in p la c einside the auger column with its open end protruding a shortdi s tance beyond the end of the column. W h i l e advancing thecolumn, soil enters the non-rotating s a m p l i n g barrel. A f t e r a5 - f t ( 1 . 5 2 - m ) advance, the s ampl e r is wi thdrawn, and the l iner(if u s e d ) is removed and c a p p e d .

9.4.6.3 Comments—The continuous sample tube sys t emreplace s the p i l o t head a s s embly in the ho l l ow- s t em augercolumn. Because of this , s ampl ing speed is great ly increasedsince the p i l o t a s s embly does not have to be removed be for etak ing a sampl e . The cont inuous s a m p l e tube system is best

used in c lay s , s i l t s , and in f i n e grained sands. It can be used tosample soils that are much more conso l idated or harder thancan be s ampl ed with S h e l b y tubes.

9.4.7 Piston Samplers:9.4.7.1 Description—Locally sa tura t ed ( f o r e x a m p l e ,

perched ground water), or cohe s i onl e s s s o i l s , and very s o f tsoi l s or s l u d g e s may not be retained in most sampl er s , evenwhen they have been f i t t e d with retainer baskets or flap valves.Piston samplers are o f t e n used under these conditions. Thesampler consi s t s of a s a m p l i n g tube, an internal p i s t o n , and adrive head. The pi s ton f i t s snugly inside the tube. The pi s ton isattached to a rod a s s embly or a cable that l eads to the surface.T u b e s made of steel are avai lab l e in 5.5 and 30-in. (13.97 and76.20-cm) and 5 - f t (1 .5-m) l e n g t h s with 0.75. 2, 3, 4, and 5-in.(1.91, 5.08, 7.62, 10.16, and 12.70-cm) ins ide d iameter (22,23). When equ ipped with a hardened steel drive shoe, the tubecan be f i t t e d with a l iner made of aluminum clear P V C , oranother material (see F i g . 19) (24). A version of the samplerdes igned for peat s a m p l i n g has a cone shaped p i s t o n (8).

9.4.7.2 Sampling Method—Prior to s a m p l i n g , the p i s t on isp l a c e d at the base (advancing e n d ) of the tube. The s a m p l e r isthen at tached to dr i l l rods and lowered down the borehole orh o l l o w - s t e m auger column to the bottom of the hole ( t o p of thes a m p l i n g i n t e r v a l ) . The s a m p l e r is then pushed or driven intothe s a m p l i n g interval. As the tube moves downward, the p i s t onremains s tat ionary and in contact with the top of the soilsample . When the s a m p l e r is wi thdrawn, soil is retained

t§f H o l l o wS t e mA u g e r

<** S a m p l i n g. . . - .Tube

F I G . 1 8 C o n t i n u o u s S a m p l e T u b e S y s t e m829

D4700

• S a m p l e r Head

- S a m p l e Tube-Actuator Rod

• Piston— — C u t t i n g T i p

F I G . 1 9 Pis ton S a m p l e rbecause of suction that deve lops between the pi s ton and thesoil core within the sampler. T h i s suction is stronger than the

on at the bottom of the sampler that would tend to extract/rom the sampler. Even so, it is o f t e n u s e f u l to twist the

sampl er with the d r i l l rods prior to retrieval, to break suction atthe bottom end and ensure that the sample will not be p u l l e dout of the sampler.

9.4.7.3 Comments—Average recovery ratios greater than0.9 can be attained with this s ampl ing tool (24, 25). However,because the s a m p l e r d ep end s on d e v e l o p m e n t of suction

between the sample and the p i s t on, it may not work inunsaturated, coarse grained sands and gravels. T h i s is due tothe high air permeabi l i ty of such material that prevents thecreation of suction with the sampler. S a m p l e s c o l l e c t ed withpi s ton samplers are r e la t iv e ly undisturbed. Zapi co et al. (24)described techniques for extracting f l u i d samples d irec t ly froml iners, and for converting liners into permeameters.

R E F E R E N C E S(1) Soil Survey Staf f , Soil Survey Manual, U.S. Dept. o f A g r i c u l t u r e ,

Super in t endent of Documents, Washington, D.C., 1951.(2) Acker, W. L., Basic Procedures for Soil Sampling and Core Drilling,

Acker Dril l Co. Inc., Scranton, Pa, 1974.(3) Materials T e s t i n g Division, Catalog of Products, Soi l t e s t Inc., Evan-

ston, I l l i n o i s , 1983.(4) Bureau of Reclamation, Earth Manual, U.S. Dept. of the Interior,

United S t a t e s Government Printing O f f i c e , Washington, D.C., 1974.(5) S a l e s Division, Catalog of Products, Soi lmoi s tur e Equipment Corp.,

Santa Barbara, C a l i f o r n i a , 1988.( 6 ) S a l e s Divis ion, Catalog o f Products, A r t ' s M a n u f a c t u r i n g a n d S u p p l y ,

American Fall s , I d a h o , 1988.(7) S a l e s Division, Catalog of Products, Brainard K i l m a n , Stone Moun-

tain, Georgia, 1988.( S ) E v e r e t t , L. G., and W i l s o n , L. G., Permit Guidance Manual on

''nsaturated Zone. Monitoring For Hazardous Waste Land Treatmentits, EPA/530-SW-86-040, 1986.

ies Division, Catalog of Products, VI-COR Technologie s Inc.,Bellevue , W a s h i n g t o n , 1988.

(10) S a l e s Division, J.M.C. Soil Investigation Equipment, Catalog No. 6,Clements Assoc iate s Inc.

(11) Hvorslev, M. J., Subsurface Exploration and Sampling of Soils forCivil Engineering Purposes, U . S . Army Corp of Engineers, Water-ways Experiment Station, Vicksburg, M i s s i s s i p p i , 1949.

(12) Wil son, J. T, and M c N a b b , J. R, "Biological T r a n s f o r m a t i o n ofOrganic Pol lu tan t s in Ground Water," EOS-Transactions, AGU, Vol64, pp. 505-507.

(13) Brakensiek, D. L., Osbom, H. B., and Rawls, W. L., Field Manual farResearch in Agricultural Hydrology, Agriculture Handbook No. 224,Science and Education A d m i n i s t r a t i o n , Uni t ed S t a t e s DepL of Agri-culture, Washington, D.C., 1979 (revised), pp. 258-275.

(14) Sharma, P. K., and DeDalta, S. K., "A Core S a m p l e r for P u d d l e dSoil s ," Soil Science Society of America Journal, Vol 49, 1985, PP-1069-1070.

(15) S a l e s Divi s i on, Catalog of Products, L i t t l e Beaver Inc. , L i v i n g s t o n ,Texas, 1988.

(16) Scalf, M. R., M c N a b b , J. R, Dunlap, W. J., Cosby, R. L., and

830

D4700Fryberger , J., Manual of Groundwater Sampling Procedures, Na-tional Water W e l l Asso c ia t i on , D u b l i n , Ohio, 1981.

(17) Driscol l , F. G., Groundwater and Wells, Johnson Division, St. Paul,Minnesota, (2nd ed.), 1986.

(18) S a l e s Divi s ion, Catalog of Products, M o b i l e D r i l l i n g Co. Inc.,I n d i a n a p o l i s , I n d i a n a , 1988.

(19) H a c k e t t , G., "Dri l l ing and Cons truc t ing Moni tor ing W e l l s withH o l l o w - S t e m Augers Part 1: D r i l l i n g Considerations," Ground WaterMonitoring Review, NWWA, Fall 1987, pp. 51-62.

(20) R i g g s , C. O., "Soil S a m p l i n g in the Vadose Zone," Proceedings of theNWWAIU.S. EPA Conference on Characterization and Monitoring ofthe Vadose Zone, NWWA, Las Vegas, N e v a d a , 1983, pp. 611-622.

(21) Sale s Division, Product Literature, Pitcher Dril l ing Co., Palo A l t o ,C a l i f o r n i a , 1986.

(22) S a l e s Div i s i on , Catalog of Products, Diedrich D r i l l i n g E q u i p m e n t ,LaPorte , Indiana , 1988.

(23) S a l e s Division, Instrumentation for Soil and Rocks, Catalog ofProducts, S o l i n s t , Bur l ing ton , Ontario, Canada, 1988.

(24) Z a p i c o , M. M., Val e s , S.( and Cherry, J. A., "A W i r e l i n e Core Barrelfor S a m p l i n g Cohes ionle s s Sand and Gravel Below the W a t e r Table."Ground V/ater Monitoring Review, NWWA, S p r i n g 1987, pp. 75-82.

( 2 5 ) S h u t e r , E., T e a s d a l e , W. E., " A p p l i c a t i o n of D r i l l i n g , Coring, andS a m p l i n g Technique s to T e s t H o l e s and W e l l s , " U.S. Geol. SurveyTechniques of V/ater Resource Investigations, Book 2, C h a p t e r F-1,1989.

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