1
CASE STUDIES: FOUNDATIONS OVER ARTESIAN
GROUNDWATER FORMATIONS
Christopher R. Byrum, Ph.D., P.E.Soil & Materials Engineers IncSoil & Materials Engineers, Inc.Plymouth, MI Office
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Formation of Artesian Conditions
From Dorr & Eschman “Geology of Michigan”
From Michael S. GaberMDEQ “Flowing WellHandbook”
3
GENERAL:
*3% of MI Wells
First Reports 1100A.D.In Belgium/Netherlands
Key to Winter SurvivalBefore Electricity
Inspired Well DrillingTechnology
Extreme-Alvin, Texas120 feet of Head!
Rose City:270 gpm 2” dia
Cedar, MI:450 gpm, 4” dia.69 feet above groundg
4
Naubinway:Highest in MI !84 feet above groundg
Some Other Well Known Spots.
CASE 1Huron River:20-30 feet aboveRiver Level
5
CASE 2Tobacco River:≈ 10 feet aboveRiver Level
BRIDGE HOT SPOTS
*Lakebed/TillInterface ZoneWith GlacialSpillway Channels.
*Glacial SpillwaysInland.
BLUES = Ancient Glacial LakebedGREENS/BROWNS = Glacial Moraine Ridges
Off-WHITE = Glacial Spillway Channels
SITE 1
6
Old Dixboro Road over Huron River
Ambulances were often stuck waiting for the Trains
Existing Bridge
7
Relocated Roadway
Existing Bridge
New Bridge:Spans River, RR andSewage Plant Drive
8
N
HURON RIVER
HURON RIVER
9
Artesian Zone
HURON RIVER
Fort Wayne
Initial Glacial Lakebed Clay Deposition
From Dorr & Eschman “Geology of Michigan”
Fort WayneDefiance
Glacial Re-Advance, Over-Consolidates initial Lakebed Clay New Lakebed Clay Deposition
Upper Clays SPT = 10-30 bpfLower Clays SPT = 50-100+ bpf
From Dorr & Eschman “Geology of Michigan”
10
Fort WayneDefiance
Inter-Lobate Zone
Head Below Lakebed Clays
Huron Channel Cuts Through Lakebed at Some Places
From Dorr & Eschman “Geology of Michigan”
Year 1904Artesian Water Map
A850
D700
C750
B800
SITE
River Water Elev. ≈735 Feet (-25)
Artesian Elev. ≈760 Feet
Bridge Footing Elev. ≈720 Feet (-40)
Green = Artesian Pressure Head Contours
Ann Arbor
YpsilantiSITE 720 Feet ( 40)
Top of Clay Cover. ≈708 Feet (-52)
Clay Cover Thickness10-20 feet
Natural Barrier GradientΔH/ ΔL = 25/10 = 2.5> 1.0 unstable
p
Saline
Year 1904Artesian Water Map
A850
D700
C750
B800
SITE
River Water Elev. ≈735 Feet (-25)
Artesian Elev. ≈760 Feet
Bridge Footing Elev. ≈720 Feet (-40)
Green = Artesian Pressure Head Contours
SITE 720 Feet ( 40)
Top of Clay Cover. ≈708 Feet (-52)
Clay Cover Thickness10-20 feet
Natural Barrier GradientΔH/ ΔL = 25/10 = 2.5> 1.0 unstable
Implies Head-Loss Through theCover Soils in the Spillway
11
Evaluating Chance of Artesian Being Present
SITE
4 Miles
Ice Margin Lateral Spillway
SITE
Primary Interlobate Spillway
950 920
850
830
800
880
950 850900
4 Miles
SITE=730
748730
870
770
750
850770
770
790
880
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General Dixboro Artesian ConditionsElev 900-950
Ground Elev 730Artesian Elev 760
From Dorr & Eschman “Geology of Michigan”
4 Miles
Probable Artesian Was Identified BeforeGeotechnical Evaluation, SO:
Artesian Drilling Protocol Was Used:
1. Do not poke a hole into the artesian within the proposed cofferdam limitsproposed cofferdam limits.
2. Do not poke a hole into the artesian where you cant seal it (Barge Test Hole performed in the middle of a River).
Artesian Drilling Protocol Was Used:
3. Use Special Drill Rigs with ability to grout and drive casing (Water Well Rigs).
4 Do poke a few holes into the Artesian in select areas4. Do poke a few holes into the Artesian in select areas that can be sealed and measure:
A. the static head and flow rate.B. the cover soil type/thickness.C. the artesian soil type and thickness.D. depth to hard bottom below the artesian soil.
13
Dixboro- We Never Found The BottomTwo deep holes were attempted (each side of the river)
but terminated within the artesian sands because:
1. 14-18 hours per test hole (Tough Holes).
2. Artesian formation was very dense to extremely dense sands with low production ratessands with low production rates .
3. Erosion was getting bad after drilling almost 50 feet into the artesian formation.
4. Drill Crew Chief Said.. Seal it “Now or Never”.
SOIL BORING LOCATION DIAGRAM
N
N
14
Beach Sands
Erosion Wash
Peat Marsh
Channel AlluviumElev. 820 ft
Existing River
Natural ground line
Huron River Valley Section Along New Roadway
Silty Clay Cover
Sand with High Artesian Pressure
Elev. 690 ft
Clay Cover is Thin Below RiverGlacial Spillway Scour Limit
Sta. 0+240 mSta. 1+060 m
Artesian conditions were close to the Ground Surface and intense at this site
Flow out of SB5 Casing
Flow out of SB5 Casing created the “SME Creek”
Artesian Flow and Casing at SB5
15
SB5
Engineered Scour Countermeasure
Artesian water has high mineral content.
•SB5 did not flow during or just after completion of drillingp g
•It took a few months for piping instability to develop through the bore hole
16
Piping Instability- Hydraulic Gradient, i =
Sand- Atmospheric
LHΔΔ
HΔG.W.T.
Artesian Pressure Head
Piezometers
Clayey Cover
Artesian Sand
LΔ
LH
ΔΔ
= in-situ barrier gradient
Piping Instability- Hydraulic Gradient, i =
Sand- Atmospheric
LHΔΔ
HΔG.W.T.
Artesian Pressure Head
Partial Penetration Holes
Clayey Cover
Artesian Sand
1LΔ2LΔ
3LΔ4LΔ
1LH
ΔΔ
4LH
ΔΔ
= in-situ = approaching ∞
IF:
Hydraulic Gradient, i = > Piping Threshold
THEN:
LHΔΔ
Piping will eventually Blow Through !!!!
Who knows how long it will take !!!
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Erosion Equilibrium – Hydraulic Shear Stress “Particle Plucking”
How Does Piping Initiate ? Something Like This.
LΔ
Time
3LΔ4LΔ
2LΔ
1LΔ
Piping Instability- Hydraulic Gradient, i =
Sand- Atmospheric
LHΔΔ
HΔG.W.T.
Artesian Pressure Head
Partial Penetration Holes
Clayey Cover
Artesian Sand
1LΔ2LΔ
3LΔ4LΔ
1LH
ΔΔ
4LH
ΔΔ
= in-situ = approaching ∞
CRITICAL PENETRATION?
Erosion Equilibrium – Hydraulic Shear Stress “Plucking”
How Does Piping Initiate ? Something Like This.
LΔ
“Blow-Holes” Become filled in with coarser sands under hydrostatic uplift = QUICK SAND
Time
3LΔ4LΔ
2LΔ
1LΔ
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30 to 40 ft
From Michael S. GaberMDEQ “Flowing WellHandbook”
10-ft
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Hammer = Very Simple Single Piston Diesel Engine
Exhaust
Driving a Crane onto a Floating Barge
Driving a Crane onto a Floating Barge
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Pier 4 Cofferdam
Pier 3 Cofferdam
Pier 3 Cofferdam
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Pier 3 Cofferdam
Pier 2 Cofferdam
Jet Grouting Equipment and Platform (crane mats on I-beams) resting on the Pier 2 Cofferdam
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Jet-Grouting Equipment
Jet-Grouting Equipment
Jet-Grouting Equipment
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Jet-Grouting Equipment
Jet-Grouting Equipment
Jet-Grouting Equipment
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Jet-Grouting 100% Overlapping Pattern/Sequence
By Hayward Baker, Inc.
Jet-Grouting Cross Section
Settlement
By Hayward Baker, Inc.
Reduction and Cofferdam Seal “All-In-One”
Pier 1- Jet Grout Soil-Cement Testing Summary
0
200400
600800
1000
1200
1400
16001800
2000
0 7 14 21 28 35Sample Age days
Unc
onfin
ed C
ompr
essi
ve S
tren
gth,
psi
ws-Col.3-5.5'ws-Col.3-0.5'ws-Col.19-5.0ws-Col.19-4.0ws-Col.8-4.0ws-Col.8-3.0ws-Col.6-6.0ws-Col.6-5.0ws-Col.3-2.5ws-Col.3-3.5ws-Col.4-2.5ws-Col.4-3.5ws-Col.5-2.0ws-Col.10-3.5ws-Col.10-1.5ws-Col.9-3.0ws-Col.9-2.0C1-Run2-Part3C2-Run1-Part1C2-Run1-Part3C3-Run1-Part1aC3-Run1-Part1bC3-Run2-Part2C3-Run2-Part3
updated 12/27/2004Sample Age, days updated 12/27/2004
Pier 1 Grout Strengths
0500
1000150020002500300035004000
11/17 11/18 11/19 11/20 11/21 11/22 11/23
Construction Date
Com
pres
sive
Str
engt
h,
psi
71428
Test Age, days4230
25
Median Soil Cement and Grout Strength Values
10001500200025003000350040004500
Unc
onfin
ed C
omp.
psi
P1 S.C.P1 GroutP2 S.C.P2 GroutP3 S.C.P3 Grout
0500
0 7 14 21 28
Wet Sample Age, days
U Design Minimum Strength = 300 psi
Hayward-Baker Staff Recover a Jet-Grouted Soil Cement Core
Jet-Grouted Soil-Cement Core
26
Column Interface is Well Bonded
Stiff-Hard Clay and Jet Grouting Don’t Mix Well
Pier 4 Cofferdam
27
Tremie-Poured Concrete Mud-Mat ?
1. Placed Underwater like a Tremie Seal.
2. However, too thin to meet Tremie Design Criteria for Required Bond + Weight to manage River head.
Pier 4 Cofferdam
Observed Artesian FlowDuring Sheet Removal
Short Sheet Removed“Vent Sheet?”
Pier 4 Cofferdam
White/Gray Flour Color is Eroding Gray Lakebed Clays !!
Cofferdam Contractor new something was wrong when water inside didn’t “clear up”
28
While Attempting First Dewatering of Cofferdam--
Pier 4 Cofferdam Dewatered to top-of-tremie
Uncontrollable 300-500 GPM flow blew under the mud mat and out the far side causing obvious major erosion beneath the footing mud mat.
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Cofferdam SheetsAnd Mud Mat
Old River Bank Sea-Wall
Cofferdam Sheets
Old River Bank Sea-WallInitial Flow
Cofferdam Sheets
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Old River Bank Sea-WallInitial Flow
Cofferdam Sheets
Major Erosion Beneath One of the Two Pier Columns.
Sheet-Pile Cofferdam
normal river level
Sea Wall SheetingArtesian head
Before Dewatering Artesian Sands
Clay Cover
Original Flow Hole Up Sea Wall
Sheet-Pile Cofferdam
normal river level
Artesian head
After Dewatering Artesian Sands
Clay Cover
Finds New “Path of Least Resistance”After dewatering cofferdam
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Do we need an Artesian Dewatering Well?
OR
Can we install the foundation without Lowering the Artesian Pressure Head?
Artesian Dewatering Well-REQUIRED
Pressure Grouting of Mud Mat-REQUIRED
**Too much flow to pour concrete, and obvious erosion under mud mat going on
Artesian Dewatering Well
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800 gpm Artesian Dewatering Well
800 gpm Artesian Dewatering Well
Artesian worm-hole outlet needed special attention
33
Lots of Silty Clayey Erosion Mud Flowed out on top of Mud Mat
218
220
222
224
226
Dow
n El
ev, m
Draw Down Estimates - NAVFAC
212
214
216
218
0 5 10 15 20
Distance from Well, m
Dra
w D
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218
220
222
224
226
Dow
n El
ev, m
B.O.F.T.O.F.
Draw Down Estimates - NAVFAC
212
214
216
218
0 5 10 15 20
Distance from Well, m
Dra
w D
0 228.2575 226.8
Draw Down Elev = -0.0193(Flow Rate) + 228.25
218220222224226228
atio
n, m
eter
s
Flow Rate vs. Draw Down Estimates - NAVFAC
212214216218
0 200 400 600 800Flow Rate, gpm
Ele
va
To get 213 m use min. 800 gpm well
Dixboro Rd over Huron RiverArtesian Well Draw-Down
216
218
220
222
224
226
228
Hea
d El
ev. m
212
214
216
0-Jan 1-Jan 2-Jan 3-Jan 4-Jan 5-Jan 6-Jan 7-Jan 8-Jan
Date
Actual Well Reached 213 meters at about 6 days at constant flow averaging 800- 1,000 gpmThis is about 8,000,000 Gallons
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Pier 4 Footing Pour
Pier 4 Footing Pour
800 gpm Artesian Dewatering WellFlows reduces to about 100-200 gpm when fully developed
Pier 4 Footing Pour
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Pier 4 Footing Pour
Pier 4 Footing Pour
Pier 4 Footing Pour
37
Pier 4 Footing Pour
Pier 4 Footing Pour
Pier 4 Footing Pour
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Pier 4 Footing Pour
Pier 4 Footing Pour
Pier 4 Footing Pour
39
Grouting of Artesian Erosion Damage to Pier 4 Footing
Grouting of Artesian Erosion Damage to Pier 4 Footing
Grouting of Artesian Erosion Damage to Pier 4 Footing
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Grouting of Artesian Erosion Damage to Pier 4 Footing
Grouting of Artesian Erosion Damage to Pier 4 Footing
Grouting of Artesian Erosion Damage to Pier 4 Footing
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Grouting of Artesian Erosion Damage to Pier 4 Footing
Grouting of Artesian Erosion Damage to Pier 4 Footing
Grout Volume Pumped was Roughly Equal to a 1-ft diameter Tube, 60 Feet Long.
This matched the Eye-Ball Reality Check Factor
Pressure Gage Broke, So we Grouted until we “Heard Cofferdam Walls/Welds Make Noises”Heard Cofferdam Walls/Welds Make Noises
This is Not The Best Way to Control Grouting.
42
Pier 4 Settlement
-20
-15
-10
-5
0
5
ttlem
ent,
mm Beams
Deck Steel/Forms
Concrete Deck
Pier Weight2 mm
15 mm12 mm
Settlement Monitoring Required !!
-35
-30
-25
3/9 3/29 4/18 5/8 5/28 6/17 7/7 7/27 8/16 9/5
Date
Set
East
West
Avg.
Concrete Deck
Concrete Barrier and Initial Live LoadEst.
24 mm27 mm
Pier 4 Settlement
-20
-15
-10
-5
0
5
ttlem
ent,
mm Beams
Deck Steel/Forms
Concrete Deck
Pier Weight2 mm
15 mm12 mm
Settlement Monitoring Required !!
-35
-30
-25
3/9 3/29 4/18 5/8 5/28 6/17 7/7 7/27 8/16 9/5
Date
Set
East
West
Avg.
Concrete Deck
Concrete Barrier and Initial Live LoadEst.
24 mm27 mm
Allowable Footing Pressure based on 1” (25.4 mm)predicted settlement
Pier 4 Settlement
-20
-15
-10
-5
0
5
ttlem
ent,
mm Beams
Deck Steel/Forms
Concrete Deck
Pier Weight2 mm
15 mm12 mm
Settlement Monitoring Required !!
-35
-30
-25
3/9 3/29 4/18 5/8 5/28 6/17 7/7 7/27 8/16 9/5
Date
Set
East
West
Avg.
Concrete Deck
Concrete Barrier and Initial Live LoadEst.
24 mm27 mm
Differential Settlement (left vs. right) = 5-6 mmBeing greater on the undercut/weak clay side
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44
45
Permanent Artesian Vent
Permanent Artesian Vent
Completed New Dixboro Road Bridge
46
Completed New Dixboro Road Bridge
Completed New Dixboro Road Bridge
Completed New Dixboro Road Bridge
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ARTESIAN FLOW CASE STUDY: Lang Road Bridge over theMiddle Branch Tobacco River
Christopher R. Byrum, Ph.D., P.E.Soil & Materials Engineers IncSoil & Materials Engineers, Inc.Plymouth, MI Office
SITE
SITE
48
SITE
SITE
SITE
49
SITE
GLACIAL LAKEBED LIMITS
SITE
SITE
50
DIXBOROLANG
Head Below Lakebed Clays
Huron Channel Cuts Almost ThroughAnd Probably Does Cut Through at Some Places
From Dorr & Eschman “Geology of Michigan”
SITE (low res. image)
51
Artesian Drilling Protocol was used! WHY?
Existing Artesian Pond located about 150 feet from bridge, with water at about 5-10 feet above River, and pipe sticking out of the ground with flowing artesian water.
Aerial Photos showing lots of Houses with Ponds
This caused me to check MDEQ Well Logs near the bridge–All were flowing wells, encountering the artesian flows.
Artesian Drilling Protocol was used! WHY?
RESULTS- Clay was too hard to drill through so we hit auger refusal at less than 30 feet deep, before encountering any artesian layers.
We didn’t know how deep it was but we new it was there.
Footing Design Recommendations
1. Use spread footings on hard clays, set as high as possible. Do not drive or pre bore deep piling down towards the Artesian. (Standard Convention would be Pre-Bored Piling)
2. Use permanent sheeting cofferdams with toe as high as practical, and tremie poured seals. (Standard Convention would be Mud Mat for this type of soil, with no toe limits)
3. If scour is deep, set footings higher and use permanent sheeting special designs to deal with scour design depth.
52
First Unusual Signs at the Site
TEST HOLES
Cofferdam Sheets in this Area Drove Deep with little Resistance
About 2 Days after Dewatering, Artesian Blew Through Here.
53
EROSION VOID
54
Grouting Results
1. Grout take was large and grout did appear on outside of cofferdam sheeting.
2. Grout stayed in place in all ports accept the port closest to the flow SOURCE HOLE.
3. Decided to create a permanent vent over SOURCE HOLE, out through rip rap. Design a……….
PERMANENT PREFERRED FLOW LOCATION
55
For the West Side, Artesian Blew Through Here.
Grouting NOT Required Here- Middle of Ftng Likely will “bridge”
Grouting Required Here- Edge of Ftng/Wing Wall Could Separate
56
Possible Cracks/Fissures Through Lakebed Clay
Michigan’s State Fossil:MASTADONPost-GlacialFurry Beast
M E I d zd x
=2
2