8_chapter 8 types of rock slope failures- kinematic feasibility
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Lateral release surfaces
Unstable block
Direction ofmovementcontrolled by lateral release surfaces
Basal slip plane
Trace of the discontinuityrepresenting the basal slip plane in the face
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Dip directionof slope face
Angle offriction
Dip of slope face
Poles falling in this zone represent potentialplane slip surfaces
Limits on dipdirectionfor slip plane
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Dip direction of slope
Slope angles, !
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30˚ friction cone
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$/.3"'3+#.( 0#1.* 7) $#.3#1"+.2 34/ ,#-/ ,-#3 '"/ 1(/*: _"/'3 $+"$-/( '"/
*"'5. 3# 34/(/ '.* 34/ +.3/"(/$3+#.( +*/.3+@/*: ! O1'-+3'3+9/ '((/((&/.3
#0 34/+" +&,#"3'.$/ 3# (3'7+-+3) +( 34/. &'*/ 1(+.2 34/ #9/"-') */($"+7/*
'7#9/: ! (/&+EO1'.3+3'3+9/ /9'-1'3+#. $'. 7/ #73'+./* 7) 3'%+.2 +.3#
$#.(+*/"'3+#. 34/ "/-'3+9/ +&,#"3'.$/ #0 /'$4 ,#-/ $#.$/.3"'3+#. 54+$4
&') 7/ '((/((/* #. 34/ 7'(+( #0 ,/"(+(3/.$/:
Dip directionof slope face
Angle offriction
Dip of slope face
Intersections falling in thiszone represent potentialplane slip surfaces
6.7' &'I ;*1,30/23.*1 *- 39% D%+7% -".$/0% *=%0$"> ?-0*5 )"04$"1+@ (AH:C
;8@A!=: B ;<89/ ,= 5,67 /1,89 =201>59/? 7039!2;06 =92/0@010;<
45G
>-'./ 0'+-1"/ &') 7/ "/2'"*/* '( ' (,/$+'- 0#"& #0 5/*2/ 0'+-1"/: !
7-#$% 1.*/"2#+.2 ,-'./ 0'+-1"/ 4'( ' (+.2-/ (-+*+.2 (1"0'$/ '.* +( 7#1.*/*
7) -'3/"'- "/-/'(/ (1"0'$/(: ;4/ +.3/"(/$3+#. 7/35//. 34/ *+($#.3+.1+3+/(
"/,"/(/.3+.2 34/ -'3/"'- "/-/'(/ (1"0'$/( '.* 34/ (-+, (1"0'$/ 5+-- ',,/'"
5+34+. 34/ $"/($/.3 #0 34/ 5/*2/ 0'+-1"/ #9/"-'): G3 +( ./$/(('") 34/"/0#"/
3# $-'((+0) ,#3/.3+'--) 1.(3'7-/ 5/*2/( +.3# (+.2-/ ,-'./ (-+*+.2 7-#$%(
H,-'./ 0'+-1"/I '.* *#17-/ ,-'./ (-+*+.2 7-#$%( H5/*2/ 0'+-1"/I: B#$%+.2
H=RY]I */($"+7/( ' (+&,-/ 3/(3( 7'(/* #. 34/ *+, *+"/$3+#.( #0 34/ 35#
,-'./(? 34/ -+./ #0 +.3/"(/$3+#. '.* 34/ (-#,/ 0'$/: M#.(+*/" 35# ,-'./(
! '.* F 5+34 *+, *+"/$3+#.( (4#5. +. J+2: <:]: G0 *+, *+"/$3+#. #0 ,-'./ !
N
Plane B
Plane A
Intersection ofA and B
Cut slope
N
Plane B
Plane A
Intersection ofA and B
Cut slope
(a)
(b)
6.7' &'J K 5%39*+ -*0 +%3%05.1.17 D9%39%0 " <*3%13."$$> /1,3"#$% D%+7%
D.$$ ,$.+% *1 *1% *0 3D* <$"1%, ?-0*5 L*24.17@ (AHJC' ?"C M$.+.17 *1 <$"1%
K' ?#C M$.+.17 *1 .13%0,%23.*1 *- K "1+ N
789:! ;9<:7= >? /,01 234 5,67 /1,89 93:0399503:
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0'--( 7/35//. 34/ *+, *+"/$3+#.( #0 34/ (-#,/ 0'$/ '.* 34/ -+./ #0 +.3/"E
(/$3+#. 7/35//. 34/ ,-'./(? (+.2-/ ,-'./ (-+*+.2 5+-- #$$1" #. ,-'./ !
HJ+2: <:]H'II: G0 ./+34/" ,-'./ 4'( ' *+, *+"/$3+#. 7/35//. 34'3 #0 34/
(-#,/ 0'$/ '.* 34/ -+./ #0 +.3/"(/$3+#. 7/35//. 34/ ,-'./( (-+*+.2 5+--
3'%/ ,-'$/ '-#.2 34/ -+./ #0 +.3/"(/$3+#. H+:/: *#17-/ ,-'./ (-+*+.2I: ;4+(
3/(3 $'. 7/ ',,-+/* 3# '-- +.3/"(/$3+#.( 54+$4 0'-- +.(+*/ 34/ $"/($/.3 #0
34/ 5/*2/ 0'+-1"/ #9/"-'):
B,5794 9C2!819G*/.3+0) 34/ ,#3/.3+'--) 1.(3'7-/ 5/*2/( +. ' (-#,/ 0'$/ 5+34 *+, YU"'.* *+, *+"/$3+#. URU" /8$'9'3/* +. ' "#$% &'(( 5+34 *+($#.3+.1+3)#"+/.3'3+#.( (4#5. +. J+2: Y:T=:
N/ '"/ .#3 2+9/. '.) +.0#"&'3+#. '7#13 34/ '.2-/ #0 0"+$3+#. #" 34/
"#124./(( #0 34/ *+($#.3+.1+3+/(: G. 34+( $'(/? 34/"/0#"/? ' 0"+$3+#.
'.2-/ #0 SU" 5+-- 7/ '((1&/*:
N
AB
A
AB
C
D
B
C
C
B
D
CA
DA
BA
DBDC
CB
D
6.7' &'H ;*1,30/23.*1 *- .13%0,%23.*1 <$*3 #",%+ *1 +"3" 7.=%1 .1 6.7' H':(
;8@A!=: B ;<89/ ,= 5,67 /1,89 =201>59/? 7039!2;06 =92/0@010;<
4D6
G. #"*/" 3# +*/.3+0) 34/ ,#3/.3+'--) 1.(3'7-/ 5/*2/( +. 34+( 0'$/ +3 +(
./$/(('") 3# +*/.3+0) 34/ 4+24/(3 $#.$/.3"'3+#.( #0 ,#-/( '.* 3# 1(/
34/(/ 3# */3/"&+./ 34/ &#(3 -+%/-) -+./( #0 +.3/"(/$3+#. 34'3 5+-- #13$"#,
+. 34/ ,"#,#(/* 0'$/: ;4/ ,/'%( '((#$+'3/* 5+34 /'$4 $-1(3/" #0 *+(E
$#.3+.1+3+/( (4#5. +. J+2: Y:T= 4'9/ 7//. -'7/--/* ! 3# M +. J+2: <:Y:
;4/ 2"/'3 $+"$-/( '((#$+'3/* 5+34 /'$4 #0 34/(/ ,#-/( 4'9/ 7//.
*"'5. +. J+2: <:Y '.* 34/ +.3/"(/$3+#.( -'7/--/*: ;4/ ,#+.3 #0 +.3/"E
(/$3+#. 7/35//. 35# 2"/'3 $+"$-/( "/,"/(/.3( 34/ #"+/.3'3+#. #0 34/
-+./ #0 +.3/"(/$3+#. 7/35//. 34/ ,-'./( 34/) "/,"/(/.3:
;4/ #9/"-') (4#5. +. J+2: <:< 4'( 7//. $#.(3"1$3/* 1(+.2 ' (-#,/ *+,
#0 YU" '.* '. '.2-/ #0 0"+$3+#. #0 SU": ;4+( +( (1,/"+&,#(/* #.3# 34/ ,-#3#0 +.3/"(/$3+#.( HJ+2: <:YI: !-+2.&/.3 #0 $/.3"/( +( '$4+/9/* 1(+.2 '
*"'5+.2 ,+. +. ' (+&+-'" &'../" '( 34'3 */($"+7/* +. 34/ 5#"%/*
/8'&,-/ 0#" ,-'./ 0'+-1"/: ;4/ #9/"-') &1(3 7/ "#3'3/* (# 34'3 34/
Dip direction
of slope
30˚Frictioncone
Slope angle, !
50˚60˚
70˚ 80˚
6.7' &'& ;*1,30/23.*1 *- *=%0$"> -*0 D%+7% -".$/0% D*04%+ %E"5<$%
789:! ;9<:7= >? /,01 234 5,67 /1,89 93:0399503:
4D4
;"EE)(AD &'()*+$;#,,-+.2 0'+-1"/ +.9#-9/( /+34/" #./ #" ' $#&7+.'3+#. #0 `/81"'- 3#,,-+.2
'.* 7-#$% 3#,,-+.2 H(// ;'7-/ <:=I:
J-/81"'- 3#,,-+.2 +.9#-9/( 34/ #9/"31".+.2 #0 "#$% -')/"( -+%/ ' (/"+/( #0
$'.3+-/9/" 7/'&(: ;4+( +( $#&&#. +. 34+.-) 7/**/* #" 0#-+'3/* "#$%( (1$4
'( (4'-/? (-'3/ #" ($4+(3 #" $-#(/-) C#+.3/* "#$% 54/"/ 34/ 0"'$31"/( *+,
(3//,-) +.3# 34/ 0'$/ '( (4#5. +. ;'7-/ <:=: ['$4 -')/" 3/.*( 3# 7/.*
'""#5 "/,"/(/.3+.2 34/ *+, *+"/$3+#. #0 34/ 0'$/ +( ,#+.3+.2 3#5'"*(
URU": ;4/ +.3/"(/$3+#. LM 0'--( 5+34+. 34/ D#./ #0 ,#3/.3+'- +.(3'7+-+3)HJ+2: <:RI: ;4/ B#$%+.2 3/(3 +.*+$'3/( 34'3 34+( 5/*2/ 5+-- (-+*/ '-#.2
34/ -+./ #0 +.3/"(/$3+#.:
N
A B
A
AB
C
D
B
C
C
B B
D
A
CA
DA
BA
DBDC
CB
D
D
C
DC
CBDB
6.7' &'A G,% *- *=%0$"> D.39 .13%0,%23.*1 <$*3
;8@A!=: B ;<89/ ,= 5,67 /1,89 =201>59/? 7039!2;06 =92/0@010;<
4DC
*#5.4+-- 1.*/" +3( #5.5/+243 '.* 4/.$/ 3"'.(0/"( 0#"$/ *#5.(-#,/: G0 34/
3#/ #0 34/ (-#,/ +( '--#5/* 3#	/ /+34/" 7) (-+*+.2 #" #9/"31".+.2? `/81"'-
$"'$%( 5+-- 0#"& +. 34/ 1,,/" -')/"( 3# ' (+2.+@$'.3 *+(3'.$/ 7/4+.* 3# $"/(3
#0 34/ (-#,/:
F-#$% 3#,,-+.2 +.9#-9/( 34/ #9/"31".+.2 #0 0"'$31"/E7#1.*/* 7-#$%(
'( "+2+* $#-1&.( "'34/" 34'. 4'9+.2 3# 0'+- +. `/81"/ H(// ;'7-/ <:=I: G.
34/ +*/'- $'(/ (4#5. +. J+2: <:=U ' (/3 #0 "/-'3+9/-) 5+*/-) (,'$/* *+(E
$#.3+.1+3+/( *+,,+.2 #13 #0 34/ (-#,/ '3 ' -#5 '.2-/ $#&7+./( 5+34 ' (/3
#0 &#"/ $-#(/-) (,'$/* *+($#.3+.1+3+/( *+,,+.2 (3//,-) +.3# 34/ 0'$/
3#2/34/" 5+34 ' (/3 #0 *+($#.3+.1+3+/( 54+$4 *+, (3//,-) +. ' *+"/$3+#.
',,"#8+&'3/-) ,/",/.*+$1-'" 3# 34/ 0'$/ 3# 0#"& /+34/" $#-1&.'" #" 3'71-'"
(4',/* 7-#$%( 54#(/ +.*+9+*1'- $/.3"/ #0 2"'9+3) -+/( #13(+*/ ' 7'('- ,+9#3
-+./ #" ,#+.3 -#$'3/* '3 34/ 7-#$% /*2/: ;4+( $#&7+.'3+#. #0 (3//,-) *+,E
,+.2 *+($#.3+.1+3+/( "'"/-) #$$1"( +. ,"'$3+$/: ;4/ *+, *+"/$3+#. #0 34/(/
*+($#.3+.1+3+/( .//* .#3 7/ ',,"#8+&'3/-) ,'"'--/- '.* ,/",/.*+$1-'" 3#
34/ (-#,/ 0'$/ 3# 7"+.2 '7#13 7-#$% 3#,,-+.2 0'+-1"/: !.) $#&7+.'3+#. #0
*+, *+"/$3+#.( $'. "/(1-3 +. #9/"31".+.2 7-#$%( ,"#9+*/* 34/ (,'$+.2 #0
34/ (3//,-) *+,,+.2 *+($#.3+.1+3+/( +( (10@$+/.3-) $-#(/ "/-'3+9/ 3# 34/
(,'$+.2 #0 34/ -#5 '.2-/ 7'('- ,-'./( 54+$4 *+, #13 #0 34/ 0'$/: K1$4
$#&7+.'3+#.( $'. 7/ +*/.3+@/* 7) /8'&+.+.2 34/ #"+/.3'3+#. #0 34/ -+./(
#0 +.3/"(/$3+#. 7/35//. *+($#.3+.1+3+/(: G0 34/(/ *+, (3//,-) +.3# 34/ 0'$/
+. $#&7+.'3+#. 5+34 ' -#5 *+, (/3 #0 7'('- ,-'./(? 34/"/ +( ,#3/.3+'- 0#"
3#,,-+.2:
!( 5+34 34/ #34/" 0'+-1"/ &/$4'.+(&( '. #9/"-') &') 7/ $#.(3"1$3/*
1(+.2 34/ (3/"/#./3 3# +*/.3+0) 34/ *+00/"/.3 3#,,-+.2 &#*/( +. ' (-#,/
0'$/ 0"#& *+($#.3+.1+3) #"+/.3'3+#. *'3': ;4/ $"+3/"+' 0#" 34/ $#.(3"1$3+#.
#0 34/ #9/"-') '"/ .#5 */($"+7/*:
6.7' &'(O P+%"$ +.,2*13.1/.3> 7%*5%30> -*0 3*<<$.17 -".$/0%
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;(-2$(-, '&( I$J.(,+ 2&##+-0K;4/ &/$4'.+(& #0 `/81"'- 3#,,-+.2 +.9#-9/( `/81"'- (-+, 7/35//. $-#(/-)
(,'$/* -')/"( HJ+2: <:==I: ;4/ (3//,-) *+,,+.2 0"'$31"/( &1(3 34/"/0#"/ 7/
+. ' (3'3/ #0 -+&+3+.2 /O1+-+7"+1&: ;4/ '.2-/ 7/35//. 34/ .#"&'- (3"/((
'$3+9/ +. 34/ (-#,/ 0'$/ '.* 34/ .#"&'- 3# 34/ *+($#.3+.1+3+/( 54+$4 '"/
1.*/"2#+.2 `/81"'- (-+, +( " +. J+2: <:==: G0 34/"/ '"/ .# /83/".'- 0#"$/(
#" 5'3/" 0#"$/( -+&+3+.2 /O1+-+7"+1& '-#.2 34/ (3//,-) *+,,+.2 *+($#.3+.1E
+3+/( 5+-- 7/ '$4+/9/* 54/. " " !? 54/"/ ! +( 34/ '.2-/ #0 0"+$3+#. #0 34/(/
*+($#.3+.1+3+/(: ;4/ '.2-/ " $'. 7/ /8,"/((/* +. 3/"&( #0 34/ *+, #0 34/
(-#,/ 0'$/ H#I '.* 34/ *+, #0 34/ (3//,-) *+,,+.2 *+($#.3+.1+3+/( H$I '(
" " #! #RU! $$
54/"/ #RU! $$ +( 34/ *+, #0 34/ ,#-/ 3# 34/ (3//,-) *+,,+.2 *+($#.3+.1+3):
"
"
#1
#1
$
$$ %90 –
Pole
Horizontal
Discontinuity
6.7' &'(( Q.1%5"3.2 2*1+.3.*1 -*0 R%E/0"$ ,$.<
;8@A!=: B ;<89/ ,= 5,67 /1,89 =201>59/? 7039!2;06 =92/0@010;<
4DD
a+&+3+.2 /O1+-+7"+1&5+-- #$$1" 54/. #RU! $$ % #! !: J-/81"'- 3#,,-+.2
$'. #$$1" 54/. 34/ *+, *+"/$3+#. #0 34/ (3//,-) *+,,+.2 *+($#.3+.1+3+/( +(
1, 3# SU" '5') 0"#& 34'3 #0 34/ (-#,/ 0'$/? 713 +( &1$4 &#"/ -+%/-) 3# #$$1"54/. 34/ *+00/"/.$/ +. *+, *+"/$3+#.( +( -/(( 34'. =\":;4/(/ $"+3/"+' '"/ $#&7+./* 3# 0#"& ' (3'7+-+3) #9/"-') +. 34/ 0#--#5+.2
&'../":
! K/$1"/ ' ,+/$/ #0 3"'$+.2 ,',/" #9/" 34/ /O1'- '"/' (3/"/#./3 HJ+2: Y:RI:
Z# "#3'3+#. #0 34/ 3"'$+.2 ,',/" +( "/O1+"/*:
! Q'"% 34/ $/.3"/ #0 34/ (3/"/#./3 #. 34/ 3"'$+.2 ,',/" 7) ,+/"$+.2 +3
5+34 ' *"'5+.2 ,+.:
! Q'"% 34/ *+, *+"/$3+#. #0 34/ 0'$/ 5+34 '. '""#5 ,#+.3+.2 3#5'"*( 34/
N/(3 '-#.2 34/ [N -+./ #0 34/ (3/"/#./3 HJ+2: <:=TI:
! ;"'$/ 34/ 2"/'3 $+"$-/ "/,"/(/.3+.2 34/ (-#,/ 0'$/ HJ+2: <:=TI:
! Q'"% 34/ ,#+.3 #. 34/ [N -+./ 54+$4 +( ' *+(3'.$/ ! 0"#& 34/ 2"/'3
$+"$-/ "/,"/(/.3+.2 34/ (-#,/ 0'$/ 3#5'"*( 34/ N ,#+.3: ;"'$/ 34/
2"/'3 $+"$-/ 54+$4 ,'((/( 34"#124 34+( ,#+.3 HJ+2: <:=TI: ;4+( 2"/'3
$+"$-/ "/,"/(/.3( 34/ -+&+3 #0 ,#-/( 54+$4 *+, '3 ##! !$:! ;"'$/ 35# (&'-- $+"$-/( (3'"3+.2 '3 34/ $+"$1&0/"/.$/ #0 34/ (3/"/#./3 '3
,#+.3( SU" '7#9/ '.* 7/-#5 34/ N ,#+.3 '.* 3/"&+.'3+.2 '3 34/ 2"/'3
$+"$-/ *"'5. +. 34/ ,"/$/*+.2 (3/, HJ+2: <:=TI:
Dip of slope face
Poles falling in these zones provide the potential for flexural toppling providedthe joint spacing is sufficiently close
0
15
–15
–30
30
Angle offriction
Dip directionof slope face
Limits on dipdirection
6.7' &'(: ;*1,30/23.*1 *- *=%0$"> -*0 R%E/0"$ 3*<<$.17
789:! ;9<:7= >? /,01 234 5,67 /1,89 93:0399503:
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! P/,/'3 34/ '7#9/ (3/, '3 ,#+.3( =\" '7#9/ '.* 7/-#5 34/ N ,#+.3 HJ+2:<:=TI:
;(-2$(-, '&( 3+&)* 2&##+-0K LM,2N$(%&0O 6GBCPQ
! ;4/ *+, *+"/$3+#. #0 34/ 7'('- ,-'./ &1(3 -+/ 5+34+. ',,"#8+&'3/-) TU"#0 34/ (-#,/ 0'$/ *+, *+"/$3+#.:
! ;4/ *+, #0 34/ 7'('- ,-'./ &1(3 7/ -/(( 34'. 34/ 0"+$3+#. '.2-/ #. 34'3
,-'./:
! ;4/ *+, *+"/$3+#. #0 -+./( #0 +.3/"(/$3+#. 7/35//. *+($#.3+.1+3+/( &1(3
-+/ 5+34+. ',,"#8+&'3/-) TU" #0 34/ (-#,/ 0'$/ *+, *+"/$3+#.: J#" (3//,(-#,/( 34+( $'. 7/ /83/.*/* 3# RU"
! ;4/ *+, #0 34/ -+./( #0 +.3/"(/$3+#. &1(3 /8$//* #RU! !$? 54/"/ ! +( 34/0"+$3+#. '.2-/ #. 34'3 ,-'./:
;4/ #9/"-') 7'(/* #. 34/ '7#9/ $"+3/"+' +( $#.(3"1$3/* 1(+.2 34/ 0#--#5+.2
,"#$/*1"/:
! b(/ 34/ 3"'$+.2 ,',/" 5+34 34/ `/81"'- 3#,,-+.2 #9/"-') HJ+2: <:=TI:
! L"'5 ' -+./ 0"#& 34/ $/.3"/ #0 34/ (3/"/#./3 3# ' ,#+.3 #. 34/ $+"$1&E
0/"/.$/ TU" '7#9/ 34/ /'(3/". /.* #0 34/ [N -+./: L"'5 ' (/$#.*
Dip of slope face
Angle offriction
Dip directionof slope face A
B
B
60˚ approx.for intersections
Limits on dipdirection
Intersections that fallinto zones A and Brepresent potentiallyunstable blocks whencombined with polesin zone A (basal planes)
6.7' &'(B ;*1,30/23.*1 *- *=%0$"> -*0 #$*24 3*<<$.17
;8@A!=: B ;<89/ ,= 5,67 /1,89 =201>59/? 7039!2;06 =92/0@010;<
4DF
-+./ 0"#& 34/ $/.3"/ 3# ' ,#+.3 TU" 7/-#5 34/ /'(3/". /.* #0 34/ [N -+./HJ+2: <:=SI: ;4/(/ -+./( "/,"/(/.3 34/ -+&+3( #. 34/ *+, *+"/$3+#. #0 7'('-
,-'./( '.* -+./( #0 +.3/"(/$3+#.:
! L"'5 ' (/&+E$+"$-/ #. 34/ /'(3 (+*/ #0 34/ (3/"/#./3 5+34 "'*+1( /O1'-
3# 34/ '.2-/ #0 0"+$3+#. &/'(1"/* '-#.2 34/ [N '( (4#5. +. J+2: <:=S:
;4+( "/,"/(/.3( 34/ 1,,/" -+&+3 #. *+, 0#" 7'('- ,-'./( '.* 34/ -#5/"
-+&+3 #. -+./( #0 +.3/"(/$3+#.:
! (3/"/#./3 *#/( .#3 4'9/ *+&/.(+#.( '.* (# +3 +( .#3 ,#((+7-/ 3#
"/,"/(/.3 $/.3"/ #0 2"'9+3): !.) ,#3/.3+'- 0#" 3#,,-+.2 H/+34/" `/81"'- #"
7-#$%I +*/.3+@/* 1(+.2 34/ #9/"-')( &1(3 7/ 9'-+*'3/* 7) /8'&+.+.2 34/
(,'$+.2( #0 34/ *+($#.3+.1+3) (/3( +.9#-9/*:
B,5794 9C2!819b(+.2 34/ *+($#.3+.1+3) #"+/.3'3+#. *'3' ,"/(/.3/* +. J+2: Y:T=? */3/"E
&+./ 34/ 0'$/ *+"/$3+#.( 54+$4 '"/ &#(3 -+%/-) 3# 4'9/ ' 3#,,-+.2 0'+-1"/
4'D'"* +0 34/ *+, #0 34/ 0'$/ +( YU" '.* 34/ '.2-/ #0 0"+$3+#. 0#" '-- *+($#.E3+.1+3+/( +( '((1&/* 3# 7/ SU":
!"#$%&"'
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34/ $"+3+$'- *+($#.3+.1+3) +.3/"(/$3+#.( 0#" 7-#$% 3#,,-+.2:
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(/$3+#. ,-#3 1(/* +. 34/ 5/*2/ 0'+-1"/ '.'-)(+( HJ+2: <:YI:
! K1,/"+&,#(/ 34/ #9/"-') HJ+2: <:=^I #.3# 34/ $#&7+./* ,#-/ */.(+3)
'.* +.3/"(/$3+#. ,-#3 '.* $/.3"/ 1(+.2 ' *"'5+.2 ,+.:
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$#&7+.'3+#.( #0 ,#-/( 0'--+.2 +.3# D#./( =? T '.* S '.* +.3/"(/$3+#.
0'--+.2 +.3# D#./ ^:
()&%&*+# ,#"-. /&).*%&"',
J'$/ *+"/$3+#. =<U": ;4/ 4+24/(3 $#.$/.3"'3+#. #0 ,#-/( +. (/3 L 0'--+.(+*/ D#./ T H(// J+2: <:=\I (122/(3+.2 34'3 34/"/ +( ' (+2.+@$'.3
4'D'"* 0"#& `/81"'- 3#,,-+.2 +0 34/ (,'$+.2 #0 (/3 L +( $-#(/: ;4/
+.3/"(/$3+#. #0 (/3( F '.* L H>#+.3 LF +. J+2: <:=\I +( #. 34/ /*2/ #0
34/ (/&+E$+"$1-'" (4',/* D#./ ^ 1(/* 3# +*/.3+0) 7-#$% 3#,,-+.2:
;4/"/ +( 4#5/9/" #.-) ' (&'-- '.3 HTcI #0 -#5 '.2-/ *+($#.3+.1+3+/(
7/-#.2+.2 3# (/3 ! 54+$4 4'9/ ,#-/( 0'--+.2 +.3# D#./ S H7'('- ,-'./(I:
;4+( (122/(3( 34'3 34/"/ +( -+33-/ ,#3/.3+'- 0#" 7-#$% 3#,,-+.2 '.* 34/
&'+. 4'D'"* +( 0"#& `/81"'- 3#,,-+.2: ;4/ */2"// #0 4'D'"* 5+--
789:! ;9<:7= >? /,01 234 5,67 /1,89 93:0399503:
4DB
*/,/.* ,"+.$+,'--) #. 34/ (,'$+.2 #0 (/3 L: G0 (/3 L +( 5+*/-) (,'$/*
34/. 34/ 4'D'"* 5+-- 7/ "/*1$/*:
J'$/ *+"/$3+#. T<U": >#-/( "/,"/(/.3+.2 ' (3//,-) *+,,+.2 (/3 #0 *+(E$#.3+.1+3+/( H(/3 F +. J+2: <:=]I 0'-- 5+34 34/+" 4+24/(3 $#.$/.3"'3+#.
+.(+*/ D#./ T +.*+$'3+.2 ' 4+24 `/81"'- 3#,,-+.2 4'D'"*: G. '**+3+#.?
Use with poles
Zone 4use with intersections
Zone 3use with poles andintersections
Zone 2
Zone 2
High flexural toppling hazard if joints are closely spaced
Low to intermediate flexural toppling hazard if joints are closely spaced
+High block toppling but requires a 3rd joint set to form blocks.Look for intersection in
6.7' &'(F ;*1,30/23.*1 *- 2*5#.1%+ R%E/0"$ "1+ #$*24 3*<<$.17 *=%0$"> -*0 D*04%+
%E"5<$%
;8@A!=: B ;<89/ ,= 5,67 /1,89 =201>59/? 7039!2;06 =92/0@010;<
4DG
34/ 4+24/(3 $#.$/.3"'3+#. #0 ,#-/( '((#$+'3/* 5+34 *+($#.3+.1+3) (/3 !
0'--( +.(+*/ D#./ S +.*+$'3+.2 34/ ,"/(/.$/ #0 7'('- ,-'./( 0#" 7-#$%
3#,,-+.2: ;4/ -+./ #0 +.3/"(/$3+#. 7/35//. (/3( F '.* L 0'-- #. 34/
/*2/ #0 D#./ ^ "/+.0#"$+.2 34/ -+%/-+4##* #0 7-#$% 3#,,-+.2 0'+-1"/: ;4/
4'D'"* #0 7-#$% 3#,,-+.2 +( #0 $#1"(/ 4+24/(3 54/. 34/ (,'$+.2 #0 (/3(
L '.* F '"/ &1$4 -/(( 34'. 34'3 #0 (/3 !: G. 34+( $'(/ 34/ "#$% &'((
5#1-* 7/ *#&+.'3/* 7) (3//,-) *+,,+.2 3'71-'" #" $#-1&.'" 7-#$%(:
N
B
D
B
C
A
CA
DA
CB
DBDC
BA
180˚
High risk of flexural toppling is high if set D is closely or very closely spaced
D dips @ 60˚A dips @10˚
6.7' &'(I 80%$.5.1"0> %="$/"3.*1 39% <*3%13."$ -*0 3*<<$.17 -".$/0% .1 " HO" -"2%
+.<<.17 3*D"0+, (&O" #",%+ *1 39% +"3" 7.=%1 .1 6.7' H':(
789:! ;9<:7= >? /,01 234 5,67 /1,89 93:0399503:
4EH
J'$/ *+"/$3+#. =UU": >#-/( "/,"/(/.3+.2 (/3 F 0'-- +.(+*/ D#./ T '.*#.-) ' (&'-- $#.$/.3"'3+#. #0 ,#-/( 0"#& (/3 ! 0'-- +.(+*/ D#./ S: Z#
+.3/"(/$3+#.( 0'-- +.(+*/ D#./ ^: ;4+( (122/(3( 34'3 34/ ,"+.$+,'-
4'D'"* +( '((#$+'3/* 5+34 `/81"'- 3#,,-+.2 #0 (/3 F: ;4/ (,'$+.2 #0 (/3
F 5+-- */3/"&+./ 34/ 4#5 "/'- 34+( 4'D'"* +(:
N
B
D
B
C
A
CA
DA
CB
DBDC
BA
280˚
High risk of flexural toppling from set B if spacing is close enough.High risk of block toppling on basal planes formed by set A. Sets B and D will form unstable blocks if spacing of sets B and D is much less than set A
6.7' &'(J 80%$.5.1"0> %="$/"3.*1 39% <*3%13."$ -*0 3*<<$.17 -".$/0% .1 " HO" -"2%
+.<<.17 3*D"0+, :&O" #",%+ *1 39% +"3" 7.=%1 .1 6.7' H':(
;8@A!=: B ;<89/ ,= 5,67 /1,89 =201>59/? 7039!2;06 =92/0@010;<
4E6
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