appendixes - €¦ · rod-type borehole extensometer; with mechanical or grout anchor; with dial...
TRANSCRIPT
Appendixes
Appendix A. Instrument capabilities for measuringland-surface displacement
A-1
Guidebook to studies of land subsidence due to ground-water withdrawal
A-2
Appendix A
A-3
Guidebook to studies of land subsidence due to ground-water withdrawal
A-4
Appendix B. Capabilities of existing subsidencemonitoring instruments
PROPE
RTIE
S
IN
STRU
MENT
AVAI
LABI
LITY
OPER
ATIN
G PR
INCI
PLE
DEPT
H RA
NGE
RANGE OF VERTICLE
DISPLACEMENT
MANUFACTURER
’SSE
NSI
TIVI
TYAC
CU
RAC
YM
AXIM
UM
DO
WN
HO
LE
TEM
PER
ATU
RE:
RAT
ED O
R
(ESI
MAT
ED)
MAX
IMU
M D
OW
NH
OLE
PR
ESSU
RE:
RAT
ED O
R (E
STIM
ATED
)
MAT
ERIA
LC
OM
POSI
TIO
NO
PER
ATIO
N a
nd IN
STAL
LATI
ON
(IMPO
RTA
NT
FEAT
UR
ES)
MAI
NTE
NAN
CE
RE-
QU
IREM
ENTS
& E
STI-
MAT
ED S
ERVI
CE
LIFE
SELE
CTE
DR
EFER
ENC
ES
WIR
E-TY
PE B
OR
EHO
LE E
XTEN
SOM
ETER
:w
eigh
t-ten
sion
ed: w
eigh
t anc
hore
d;w
ith ro
tary
pot
entio
met
er o
r w
ater
-leve
l rec
orde
r at s
urfa
ce
(USG
S co
mpa
ctio
n m
eter
)
Sinc
o; u
ser-f
abric
ated
(4)
Not
e (a
)
Mea
sure
ver
tical
-dis
plac
emen
t be
twee
n tw
o m
arke
rs a
t dep
th b
y co
mpa
ring
resu
lts o
f adj
acen
t in
stal
latio
n; a
cces
s to
bor
ehol
e no
t nec
essa
ry b
ut w
ire m
ust b
e fre
e to
mov
e be
twee
n bo
reho
le a
nd
trans
duce
r out
side
wel
l. A
stra
ight
hol
e (<
1/2
° incl
inat
ion)
is
des
irabl
e to
redu
ce fr
ictio
n (3
)
Max
imum
: 600
m;
Typi
cal;
up to
300
mTo
tal:
25-5
0mm
,re
setta
ble
with
wat
er-
leve
l rec
orde
r; 2.
7m
max
imum
with
rota
ry
pote
ntio
met
er.
±0.3
mm
Tota
l 1 to
1.5
mm
(3)
repo
rted.
Not
e: fr
ictio
n dr
ag a
t st
ress
reve
rsal
s m
ay
limit
tota
l len
gth
accu
racy
to ±
3 to
±8
mm
(5
)
(500
° C. (
2) a
bove
w
hich
stre
ngth
loss
may
be
com
e im
porta
nt);
no
prov
isio
n fo
r dow
nhol
e te
mpe
ratu
re
mea
sure
men
t.
not a
pplic
able
wire
usu
ally
sta
inle
ss
stee
l; m
ay b
e pl
astic
co
ated
; typ
ical
ly
1/8
in. A
ISI 3
02
stra
nded
airc
raft
cabl
e
Mov
emen
t bet
wee
n su
rface
and
an
chor
see
n as
rota
tion
of p
ulle
y at
sur
face
; cou
nter
-wei
ght a
t su
rface
mai
ntai
ns co
nsta
nt te
nsio
n on
wire
idea
lly, b
ut fr
ictio
n of
w
ire m
ay a
ffect
tens
ion
(6)
Wei
ght a
ncho
rs m
aybe
lif
ted
out o
f bor
ehol
e to
repl
ace
wire
;U
nder
sev
ere
geot
herm
al
cond
ition
s, p
ittin
g co
rrosi
on ra
te m
ay b
e
0.15
mm
•mon
th.
So a
3 m
m w
ire w
ould
se
ver i
n 1-
1/2
year
s.N
ote:
Due
to g
ener
al
corro
sion
, the w
ire m
ay
last
100
year
s, g
iven
a ra
te o
f 0.5
g/m
2 •day
(1) T
oliv
a, 1
970
(2) P
hillip
s an
d Sy
kes,
197
0(3
) De
Loos
, 197
3(4
) Lof
gren
, 196
9(5
) Rile
y, 1
969
(6) B
ull a
nd M
iller,
1975
(7) L
ofgr
en, 1
961
WIR
E-TY
PE B
OR
EHO
LE E
XTEN
SOM
ETER
; w
eigh
t-ten
sion
ed; w
ith g
rout
or
mec
hani
cal a
ncho
r; di
al g
auge
or
sens
or a
t sur
face
Inte
rfels
; use
r-fa
bric
ated
(1),
(2)
as a
bove
Typi
cal:
up to
100
mTo
tal:
10-5
0mm
re
setta
ble
±0.5
to 1
.0m
mTo
tal:
1.5
to 3
mm
es
timat
edas
abo
veno
t app
licab
leas
abo
ve; w
ire m
ay b
e en
case
d in
plas
tic
tubi
ng
Mul
tiple
wire
inst
alla
tions
po
ssib
le, b
ut m
ay no
t be
prac
tical
in
dee
p ho
les;
see
not
e a;
eas
y to
re
set r
ange
Anch
or a
nd w
ire s
yste
m
usua
lly no
t rem
ovea
ble;
lif
e un
der s
ever
e ge
othe
rmal
con
ditio
ns
may
be
1-1/
2 ye
ars
(1) W
adde
ll, 1
964
(2) S
elle
rs, 1
969
(3) C
ordi
ng e
t al,
1975
WIR
E-TY
PE B
OR
EHO
LE E
XTEN
SOM
ETER
; sp
ring-
tens
ione
d; w
ith g
rout
or
mec
hani
cal a
ncho
r; an
d di
al g
auge
or
mic
rom
eter
sen
sor a
t sur
face
Terra
met
rics;
Pet
er
Smith
; Ser
ata
Wire
stre
tche
d be
twee
n an
chor
at
dept
h and
sprin
g-lo
aded
refe
renc
e po
int a
t sur
face
. Mov
emen
t be
twee
n su
rface
and
anc
hor s
een
as d
ispl
acem
ent o
f sen
sing
rod
cont
act s
prin
g
Max
imum
: 450
mTy
pica
l: 15
-90m
Tota
l: 90
-150
mm
±0.0
3mm
Tota
l: ±0
.1m
m to
2.5
mm
re
porte
d;U
nder
min
ing
cond
i-tio
ns, a
ccur
acy
of
sing
le m
easu
rmen
t re-
porte
d to
be
±0.2
to
3mm
, whi
le s
urve
y ac
cura
cy ty
ing
in
bore
hole
col
lars
was
±6
mm
as a
bove
not a
pplic
able
as a
bove
Mul
tiple
wire
inst
alla
tions
po
ssib
le, b
ut m
ay no
t be
prac
tical
in
dee
p ho
les;
see
not
e a;
eas
y to
re
set r
ange
. Rel
ative
ly ru
gged
co
mpa
red
to e
lect
rical
tra
nsdu
cers
. Stre
tch
of w
ire d
ue
to c
hang
e in
spr
ing
tens
ion
adde
d to
read
out v
alue
.
as a
bove
(1) P
otts
, 196
4(2
) Dun
nicl
iff, 1
970
WIR
E-TY
PE B
OR
EHO
LE E
XTEN
SOM
ETER
; ca
ntile
ver t
ensio
ned;
with
gro
ut
or m
echa
nica
l anc
hor;
and
cant
ileve
r-mou
nted
ele
ctric
al
resi
stan
ce s
train
gau
ge s
enso
r at
surfa
ce
Terra
met
rics
Wire
stre
tche
d be
twee
n an
chor
and
ca
ntile
ver s
prin
g at
sur
face
. M
ovem
ent b
etw
een
surfa
ce a
nd
anch
or c
ause
s be
ndin
g of
ca
ntile
ver a
nd re
sist
ance
cha
nge
in s
train
gau
ge
Typi
cal:
150m
Tota
l: 15
mm
rese
ttabl
e±0
.01m
mTo
tal:
±0.5
mm
est
imat
edas
abo
veno
t app
licab
leas
abo
veM
ultip
le w
ire in
stal
latio
ns p
oss
-ib
lem
but
may
not
be
prac
tical
in
deep
hol
es. S
ee n
ote
a. S
ensi
tive
to m
oist
ure;
zer
o dr
ift c
an c
ause
pr
oble
ms
as a
bove
;ex
cept
sen
sor m
ay
requ
ire re
calib
ratio
n or
re
plac
emen
t at m
ore
frequ
ent i
nter
vals
(1) S
elle
rs, 1
969
(2) D
unni
cliff
, 197
0
WIR
E-TY
PE B
OR
EHO
LE E
XTEN
SOM
ETER
; sp
ring
tens
ione
d; m
echa
nica
l or
grou
t anc
hor;
roto
ry p
oten
tiom
eter
se
nsor
at s
urfa
ce
Sinc
oW
ire s
tretc
hed
from
anc
hor,
over
pu
lley (
to w
hich
pot
entio
met
er is
co
uple
d)to
spr
ing.
Mov
emen
t be
twee
n su
rface
and
anc
hor s
een
as p
ully
rota
tion
Typi
cal:
100m
ass
umed
Tota
l: 50
mm
rese
ttabl
e±0
.05m
mTo
tal:
±1.5
mm
est
imat
edas
abo
veno
t app
licab
leas
abo
veas
abo
veas
abo
ve(1
) Dun
nic
liff,
1970
WIR
E-TY
PE B
OR
EHO
LE E
XTEN
SOM
ETER
; ca
ntile
ver t
ensio
ned;
mec
hani
cal
or g
rout
anc
hor;
cant
ileve
r-m
ount
ed v
ibra
ting-
wire
stra
in
gaug
e se
nsor
at s
urfa
ce
Telm
acW
ire st
retc
hed
betw
een
anch
or a
nd
cant
ileve
r spr
ing
at s
urfa
ce.
Mov
emen
t bet
wee
n su
rface
and
an
chor
cau
ses
bend
ing
at
cant
ileve
r and
cha
nges
nat
ural
fre
quen
cy o
f vib
ratin
g w
ire
Typi
cal:
100m
Tota
l: 50
mm
±0.0
1mm
Tota
l: ±1
.5m
m e
stim
ated
as a
bove
not a
pplic
able
Stai
nles
s st
eel w
ires
as a
bove
; but
som
ewha
t mor
e re
sis-
tant
to e
nviro
nmen
tal p
robl
ems
as a
bove
(1) D
unni
cliff
, 197
0
RO
D-T
YPE
BOR
EHO
LE E
XTEN
SOM
ETER
; w
ith m
echa
nica
l or g
rout
anc
hor;
with
dia
l gau
ge o
r mic
rom
eter
se
nsor
Irad;
Inte
rfels
;Te
rram
etric
s:H
ugge
nber
ger
Soil
Inst
rum
ents
Mov
emen
t bet
wee
n an
chor
and
su
rface
app
ears
as tr
ansl
atio
n of
to
p of
rod
rela
tive
to s
urfa
ce;
Dis
plac
emen
t of t
op o
f rod
de
tect
ed b
y se
nsor
Max
imum
: 500
mTy
pica
l: 30
-180
mTo
tal:
10-5
0mm
re
setta
ble
Add
rod
leng
ths
as
requ
ired
in
exte
ntio
n: in
co
mpr
essio
n, c
an c
ut
rod
as n
eede
d
±0.0
1mm
to ±
0.03
mm
Tota
l: ±0
.02m
m to
±0
.6m
m e
stim
ated
as a
bove
not a
pplic
able
Rod
gene
rally
stai
nles
s st
eel;
occa
sion
ally
al
umin
um. M
ay b
e pl
astic
coa
ted
of
case
d in
pla
stic
tu
be.
Anch
or u
sual
ly c
adm
ium
pl
ated
mild
ste
el, o
r ca
st ir
on.
Rod
is ty
pica
lly s
mal
l di
amet
er 6
mm
sol
id
rod
- 17m
m p
ipe.
Not
e C
:
Acce
ss to
bor
ehol
e no
t req
uire
d;
but t
op o
f rod
mus
t be
free
to
mov
e be
twee
n bo
reho
le a
nd
trans
duce
r. R
od in
stal
led
in
flexi
ble
tube
if ho
le u
nsta
ble
and
requ
ires g
rout
ing.
A st
raig
ht ho
le
(1/2
° incl
inat
ion)
is d
esira
ble
to
redu
ce fr
ictio
n.
If m
ultip
le in
stal
latio
n no
t pr
actic
al fo
r dee
p ho
le, m
easu
re
verti
cal d
ispl
acem
ent b
etw
een
2 m
arke
rs a
t dep
th b
y co
mpa
ring
resu
lts o
f adj
acen
t ins
talla
tions
.
Typi
cal r
od (p
ipe)
wal
l th
ickn
ess
is 3
mm
. Bas
ed
on p
ittin
g co
rrosi
on
rate
of 0
.15m
m/m
o(1)
. Th
e se
rvic
e life
wou
ld
be a
bout
1-1
/2 y
ears
. If
som
e pi
nhol
es c
an b
e to
lera
ted,
ser
vice
life
may
be
as lo
ng a
s 10
0yrs
., ba
sed
on a
ge
nera
l cor
rosio
n ra
te
of 0
.5m
2 /day
.(1)
(1) T
oliv
a, 1
970
(2) C
ordi
ng, e
t al.,
19
75(3
) Sel
ler,
1969
RO
D-T
YPE
BOR
EHO
LE E
XTEN
SOM
ETER
; w
ith m
echa
nica
l or g
rout
anc
hor;
with
line
ar p
oten
tiom
eter
sen
sor
Inte
rfels
;Si
nco;
Irad;
Soil
Inst
rum
ents
as a
bove
Typi
cal:
30m
to 1
80m
tota
l: 10
-150
m±0
.01m
m to
0.1
mm
Tota
l: ±0
.2 to
±2m
m,
estim
ated
as a
bove
not a
pplic
able
as a
bove
as a
bove
as a
bove
; Wip
er-c
onta
cts
of
pote
ntio
met
er m
ay d
e-gr
ade
and
wea
r and
re
quire
repl
acem
ent o
r re
calib
ratio
n w
ithin
1
year
.
RO
D-T
YPE
BOR
EHO
LE E
XTEN
SOM
ETER
; w
ith m
echa
nica
l or g
rout
anc
hor;
with
LVD
T se
nsor
Inte
rfels
as a
bove
Typi
cal:
30m
to 1
80m
Tota
l: 12
mm
, re
setta
ble
±0.0
1mm
to ±
0.1m
mTo
tal:
±0.2
to +
2mm
es
timat
ed
as a
bove
not a
pplic
able
as a
bove
as a
bove
as a
bove
; exc
ept s
ervi
ce
life
of L
VDT
shou
ld b
e so
meh
at lo
nger
than
for
pote
ntio
met
er if
ad
equa
tely
sea
led.
RO
D-T
YPE
BOR
EHO
LE E
XTEN
SOM
ETER
; w
ith m
echa
nica
l or g
rout
anc
hor;
with
vib
ratin
g wi
re s
train
gau
ge
sens
or
Mai
hak
as a
bove
Typi
cal:
30m
to 1
80m
estim
ated
Tota
l: 6
to 1
00m
m±0
.003
mm
to ±
0.03
mm
Tota
l: ±0.
05 to
±1.2
5mm
re
porte
d; b
ut fr
ictio
n m
ay m
ake
+0.0
5mm
un
real
istic
as a
bove
not a
pplic
able
as a
bove
as a
bove
as a
bove
; exc
ept s
ervi
ce
life
of v
ibra
tion
wire
st
rain
gau
ge s
houl
d be
se
vera
l yea
rs
B-1
Guidebook to studies of land subsidence due to ground-water withdrawalTABLE 2.11
CAPABILITIES OF EXISTING SUBSIDENCE MONITORING INSTRUMENTS
•V
ER
TIC
AL
DIS
PL
AC
EM
EN
TS
•S
he
et
2 o
f 4
PROPERTIES
INSTRUMENT
AVAILABILITY
OPERATING PRINCIPLE
DEPTH RANGE
RANGE OF VERTICLE
DISPLACEMENT
MAN
UFA
CTU
RER
’SSE
NSI
TIVI
TYAC
CU
RAC
YM
AXIM
UM
DO
WN
HO
LE
TEM
PER
ATU
RE:
RAT
ED O
R
(ESI
MAT
ED)
MAX
IMU
M D
OW
NH
OLE
PR
ESSU
RE:
RAT
ED O
R (E
STIM
ATED
)
MAT
ERIA
LC
OM
POSI
TIO
NO
PER
ATIO
N a
nd IN
STAL
LATI
ON
(IMPO
RTA
NT
FEAT
UR
ES)
MAI
NTE
NAN
CE
REQ
UIR
EMEN
TS
& ES
TIM
ATED
SER
VIC
E LI
FESE
LEC
TED
REF
EREN
CES
RO
D-T
YPE
BOR
EHO
LE E
XTEN
SOM
ETER
,w
ith m
echa
nica
l or g
rout
anc
hor;
atta
ched
wire
at s
urfa
ce w
ith s
cale
re
adou
t
User
fabr
icat
ed (1
)M
ovem
ent b
etw
een
surfa
ce a
nd
anch
or s
een
as tr
ansl
atio
n of
top
of ro
d re
lativ
e to
sur
face
; wire
at
tach
ed to
rod
goes
ove
r pul
ley
and
is te
nsio
ned
by a
wei
ght.
Elev
atio
n of
wt o
r rot
atio
n of
pu
lley
also
are
mea
sure
men
ts o
f di
spla
cem
ent
Typi
cal:
100m
1m±2
.5m
mTo
tal:
±15m
m e
stim
ated
as a
bove
not a
pplic
able
as a
bove
as a
bove
as a
bove
(1) H
owel
l, Wrig
ht, a
nd
Dea
ringe
r, 19
76
RO
D-T
YPE
BOR
EHO
LE E
XTEN
SOM
ETER
,w
ith tw
o con
cent
ric ro
ds; m
echa
nica
l an
chor
s; a
nd d
ial g
auge
read
out
(DO
UBL
E-PO
INT
BOR
EHO
LE E
XTEN
SOM
ETER
)Irad;
Tele
met
rics
Inne
r rod
anc
hore
d at
bas
e of
bo
reho
le. O
uter
rod
exte
nds
only
partw
ay d
own
the
hole
and
is
anch
ored
. Mov
emen
t bet
wee
n su
r-fa
ce a
nd o
ther
anc
hor s
een
as
trans
latio
n of
top
of a
ppro
pria
te
rod
rela
tive
to s
urfa
ce; p
ositi
on
of in
ner o
r out
er ro
d re
lativ
e to
fix
ed m
easu
ring
surfa
ce re
ad w
ith
dial
gau
ge
Max
imum
: 15m
Tota
l: 10
0-30
0mC
an b
e in
crea
sed
in
exte
nsio
n with
exte
nsio
n ro
ds b
y 60
0m
±0.0
1To
tal:
±0.5
mm
est
imat
edas
abo
veno
t app
licab
leO
uter
rod:
gal
vani
zed
stee
l (Ira
d); p
roba
bly
15m
m.
Inne
r rod
: sta
inle
ss
stee
l.
See
note
(c);
Hol
e ca
n be
gro
uted
if
exte
nsom
eter
tool
s pl
aced
in
prot
ectiv
e tu
bes;
not
for u
se in
ca
sed
hole
s
Prob
ably
not
reco
vera
ble
for r
epla
cem
ent.
Cor
rosi
on re
sist
ance
w
ill be
hig
her f
or a
ll st
ainl
ess
stee
l as-
sem
bly;
rem
oval
of
galv
aniz
ed c
oatin
g w
ill be
rapi
d; s
ealin
g m
ay
impe
de m
ovem
ent b
etw
een
conc
entri
c pi
pes.
Serv
ice
life
prob
ably
less
than
1 y
ear d
ue to
co
rrosi
on o
f out
er ro
d an
d du
e to
sca
ling
PIPE
-TYP
E BO
REH
OLE
EXT
ENSO
MET
ER.
anch
ored
by
own
wei
ght,
atta
ched
w
ire a
t sur
face
with
wat
er le
vel
reco
rded
read
out
User
fabr
icat
ed (1
), (2
), (3
)M
ovem
ent b
etw
een s
urfa
ce an
d anc
hor
seen
as
trans
latio
n of
top
of p
ipe
rela
tive
to s
urfa
ce; w
ire a
ttach
ed
to p
ipe
goes
ove
r pul
ley
and
is
tens
ione
d by
wei
ght.
Elev
atio
n of
w
eigh
t or r
otat
ion
of p
ulle
y ar
e al
so m
easu
rem
ents
of d
ispl
acem
ent
Max
imum
: (3)
1200
mTy
pica
l: 30
0-60
0mTo
tal:
25-5
0mm
re
setta
ble
±0.0
1mm
to ±
0.03
mm
Tota
l: 0.
2 to
0.6
mm
es
timat
edas
abo
veno
t app
licab
leCa
st ir
on (3
);lo
w a
lloy
stee
l pos
-sib
le; p
ipe
typi
cally
50
mm
to 1
00m
m d
iam
eter
Pipe
usu
ally
inst
alle
d in
met
al
case
d ho
le, o
ften
aban
done
d w
ell;
pipe
usu
ally
foun
d ~5
to 1
0m b
elow
ba
se o
f cas
ing.
See
note
(c)
Pipe
sta
nds
on s
hoe;
can
pr
obab
ly b
e re
mov
ed fo
r re
plac
emen
t, bu
t with
di
fficu
lty. T
ypic
al w
all
thic
knes
s fo
r pip
e cit
ed
is 4
mm
for g
ener
al c
or-
rosi
on ra
te o
f 6g/
m•d
(4);
it wou
ld la
st a
max
imum
of
10 y
ears
in a
sev
er
geot
herm
al e
nviro
nmen
t.
(1) F
ulch
ner,
1977
(2) K
omak
i, 19
69(3
) Hiro
no, 1
969
(4) T
oliv
a, 1
970
MU
LTIP
LE B
ASE
LEN
GTH
EXT
ENSO
MET
ER,
with
indu
ctan
ce s
enso
rs, m
echa
nica
l m
etal
anc
hors
Telm
acC
entra
l rod
, abl
e to
mov
e fre
ely i
n ho
le, c
onta
ins
indu
ctan
ce-ty
pe
sens
ors.
Whe
n ro
d mov
es re
lativ
e to
conc
entri
c an
chor
s, in
duct
ance
se
nsor
s det
ect r
elat
ive p
ositi
on of
ea
ch a
ncho
r
50m
est
imat
ed;
Max
imum
of 1
sen
sor p
er
met
er
Max
imum
: 125
mm
0.01
mm
Tota
l and
inte
rval
: 0.
02 m
m c
laim
ed50
°C(5
00 K
N/m
2 est
imat
ed)
Prob
ably
sta
inle
ss s
teel
Acce
ss to
hol
e no
t nec
essa
ry, b
ut
inst
rum
ente
d ro
d m
ust b
e fre
e to
di
spla
ce to
war
d su
rface
. Will
not
work
in m
etal
cas
ing;
pro
babl
y o.
k.
if an
chor
s in
stal
led
outs
ide
flexi
ble
plas
tic c
asin
g
Cen
tral r
od c
onta
inin
g el
ectro
nics
has
no
mec
hani
cal c
oupl
ing
to
anch
ors,
so
prob
ably
coul
d be
repl
aced
.
Und
er g
eoth
erm
al c
on-
ditio
ns, c
entra
l rod
and
el
ectro
nics
hou
sing
may
su
ffer p
ittin
g an
d co
rrosi
on. E
lect
roni
cs a
s de
sign
ed n
ot s
uita
ble
for
geot
herm
al e
nviro
nmen
t; lif
e in
non
-geo
ther
mal
en
viro
nmen
t pro
babl
y 1
yr. L
onge
r if r
od
repl
aced
MU
LTIP
LE B
ASE
LEN
GTH
EXT
ENSO
MET
ER,
with
reed
sw
itch
sens
ors;
and
m
agne
tic m
arke
rs
User
fabr
icat
ed
(1, 2
, 4)
Perm
anen
t, m
ovea
ble
cent
ral r
od
cont
ains
reed
sw
itche
s, a
t ap
prox
imat
ely
sam
e sp
acin
g as
m
agne
ts a
ncho
red
outs
ide
bore
hole
ca
sing
. Ree
d sw
itche
s may
be p
aire
d or
sin
gle.
Rod
inst
alle
d so
in
itial
ly e
ach
reed
sw
itch
appr
oxim
atel
y op
posi
te m
agne
t. M
ovem
ent o
f mea
surin
g rod
nee
ded t
o al
ign
reed
sw
itch
with
co
rresp
ondi
ng m
agne
t mea
sure
d w
ith
mic
rom
eter
. Can
repl
ace
rods
with
ta
pe fo
r eas
ier h
andl
ing
30-7
0mTo
tal:
150-
250m
mIn
terv
als:
150
-250
mm
±0.0
2mm
to ±
0.1m
m±0
.1m
m(1
) repo
rted
with
ro
ds
±0.1
5mm(2
) with
tape
(50
°C e
stim
ated
; po
ssib
ly h
ighe
r sin
ce
reed
sw
itche
s ca
n op
erat
e to
200
°C)
(700
KN
/m2
estim
ated
ba
sed
on d
epth
rang
e)Ro
d: th
in-w
alle
d st
ainl
ess
stee
l tub
e w
ith p
reci
sion
co
nnec
tors
.
Tape
: Sta
inle
ss s
teel
.
Bras
s ho
usin
g fo
r ree
d sw
itche
s
Acce
ss to
hol
e no
t nec
essa
ry, b
ut
inst
rum
ent m
ust b
e fre
e to
dis
plac
e to
war
d su
rface
. May
be
slig
htly
in
fluen
ced
by s
teel
cas
ing
and
accu
racy
redu
ced
due
to d
isto
rtion
of
mag
netic
fiel
d.
Cen
tral r
od c
an b
e w
ithdr
awn
or re
plac
ed b
ut
with
loss
of a
ccur
acy.
Stai
nles
s st
eel t
ape
or
tube
wou
ld b
ecom
e se
vere
ly p
itted
in 1
1/2
ye
ars
of s
ervi
ce, b
ased
on
pitt
ing
corro
sion
rate
of
0.1
5mm
/mon
th. (
3)
Elec
troni
cs a
s de
sign
ed
not s
uita
ble
for
geot
herm
al e
nviro
nmen
tLi
fe p
roba
bly
1 yr
und
er
non-
geot
herm
al
cond
ition
s; lo
nger
if ro
d re
plac
ed
(1) B
urla
nd, M
oore
and
Sm
ith, 1
972
(2) S
mith
and
Bur
land
, 19
76(3
) Tol
iva,
197
0(4
) Bur
land
and
Moo
re,
1973
B-2
Appendix B
TABLE 2.11
CAPABILITIES OF EXISTING SUBSIDENCE MONITORING INSTRUMENTS
•V
ER
TIC
AL
DIS
PL
AC
EM
EN
TS
•S
he
et
3 o
f 4
PROPERTIES
INSTRUMENT
AVAILABILITY
OPERATING PRINCIPLE
DEPTH RANGE
RANGE OF VERTICLE
DISPLACEMENT
MAN
UFA
CTU
RER
’SSE
NSI
TIVI
TYAC
CU
RAC
YM
AXIM
UM
DO
WN
HO
LE
TEM
PER
ATU
RE:
RAT
ED O
R
(ESI
MAT
ED)
MAX
IMU
M D
OW
NH
OLE
PR
ESSU
RE:
RAT
ED O
R (E
STIM
ATED
)
MAT
ERIA
LC
OM
POSI
TIO
NO
PER
ATIO
N a
nd IN
STAL
LATI
ON
(IMPO
RTA
NT
FEAT
UR
ES)
MAI
NTE
NAN
CE
REQ
UIR
EMEN
TS
& ES
TIM
ATED
SER
VIC
E LI
FESE
LEC
TED
REF
EREN
CES
CH
AIN
-TYP
E EX
TEN
SOM
ETER
, m
echa
nica
l or g
rout
anc
hor,
with
lin
ear p
oten
tiom
eter
or L
VDT
sens
or
Soil
Inst
rum
ents
;In
terfe
lsD
evic
e co
nsis
ts o
f a lin
ear s
enso
r ho
usin
g in
a s
teel
cas
e, a
nd fi
xed
to a
con
cret
e an
chor
or a
ncho
r pl
ate.
A m
ovea
ble
rod
exte
nds
from
th
e se
nsor
cas
e at
2nd
anc
hor,
1 m
or
mor
e aw
ay. M
ovem
ent b
etw
een
anch
ored
sens
or ca
se an
d 2n
d anc
hor
dete
cted
by
sens
or.
Exte
nsom
eter
s ca
n be
cou
pled
by
usin
g 2n
d an
chor
of 1
st
exte
nsom
eter
to a
ncho
r sen
sor c
ase
of n
ext e
xten
som
eter
Typi
cal:
60-1
00m
, but
le
ad w
ire c
ould
ext
end
seve
ral h
undr
ed m
. fro
m
last
sen
sor t
o re
adou
t
Max
imum
: 10m
m to
300
mm
pe
r sen
sor
±0.1
mm
to ±
1.0m
mIn
terv
al: ±
2 to
5m
m
estim
ated
Tota
l: as
sum
ing
10
sens
ors
@10
ft
cent
ers,
±7 to
±16m
m
estim
ated
(0-5
0°C
, est
imat
ed)
(100
0KN
/m2 e
stim
ated
)Pr
obab
ly s
tain
less
ste
elG
ener
ally
use
d in
dam
s or
fills
. Re
quire
s wel
l com
pact
ed fil
l or s
oft
grou
t aro
und
anch
ors
and
no c
asin
g in
hol
e. R
ods
may
be
prot
ecte
d by
fle
xibl
e pl
astic
cas
ing.
Onl
y le
ad w
ires
exit
at s
urfa
ce; n
o ac
cess
to b
oreh
ole
nece
ssar
y
Can
not b
e re
paire
d or
re
plac
ed. L
ife lim
ited
by
sens
ors;
LVD
T pr
obab
ly
mor
e re
liabl
e th
an lin
ear
pote
ntio
met
er. L
ife
prob
ably
1 y
ear u
nder
no
n-ge
othe
rmal
con
ditio
ns
SON
DE-
TYPE
EXT
ENSO
MET
ER,
with
indu
ctio
n se
nsor
and
met
al
mar
kers
Telm
ac; M
aiha
k;
Terra
met
rics;
Sin
co;
Soil
Inst
rum
ents
Prob
e lo
wer
ed d
own
hole
on
cabl
e;
whe
n it
pass
es a
ncho
red
met
al
mar
ker,
curre
nt c
hang
e in
duce
d in
se
cond
ary
coil a
nd d
etec
ted
at s
ur-
face
. Dep
th o
f mar
ker i
s le
ngth
of
cabl
e pl
ayed
out
Typi
cal:
75m
to 1
00m
;
Max
imum
: 300
m
Idea
lly u
nlim
ited;
but
de
pend
s on
cas
ing;
up
to
≈ 17%
stra
in
poss
ible
, bas
ed o
n ty
pica
l ela
stic
co
mpr
essi
bilit
y of
ca
sing
±0.1
mm
to ±
1.5m
mIn
terv
al: 1
.25
to 5
mm
re
porte
d
Tota
l: 5
to 1
0 m
m
estim
ated
up to
110
°C(3
000K
N.m
2 est
imat
ed,
base
d on
dep
th ra
nge)
Casi
ng u
sual
ly p
last
ic.
Met
al m
arke
rs m
ay b
e an
y co
mm
on m
etal
. Inst
rum
ent
hous
ing
stai
nles
s st
eel
Best
whe
n ho
le w
ithin
3° o
f ver
ti-ca
l. M
arke
rs a
ncho
red
outs
ide
flexi
ble
plas
tic c
asin
g. A
cces
s to
ho
le re
quire
d.No
t for
use
in m
etal
cas
ing
If pr
obe
can
be m
odifie
d to
take
geo
ther
mal
co
nditi
ons,
will
be e
asy
to m
aint
ain
sinc
e re
mov
ed
betw
een
read
ings
SON
DE-
TYPE
EXT
ENSO
MET
ER,
with
2 o
r 3 in
duct
ion
sens
ors;
and
“c
asin
g co
llars
” as
mar
kers
(CAS
ING
CO
LLAR
LO
CAT
OR
)
Prov
ided
as
a se
rvic
e on
ly; b
y Dre
sser
-Atla
s,
Schl
umbe
rger
, and
ot
hers
Sond
e co
nsis
ts o
f 2 o
r 3 p
robe
s rig
idly
con
nect
ed in
ser
ies.
Wor
ks
like
abov
e so
nde
but s
ense
s ch
ange
in
met
al th
ickn
ess
at c
olla
rs; d
is-
tanc
e be
twee
n ad
jace
nt m
arke
rs d
e-te
rmin
ed b
y ca
ble
play
ed o
ut b
e-te
en p
robe
det
ectio
n up
per m
arke
r (c
olla
r) an
d lo
wer
pro
be d
etec
ting
low
er m
arke
r (co
llar).
Dep
th o
f pr
obe
also
det
erm
ined
by
whe
el o
n to
ol w
hich
trac
ks a
gain
st e
dge
of
casi
ng. W
heel
has
sev
eral
atta
ched
m
agne
ts, a
nd e
ach
parti
al ro
tatio
n of
whe
el d
etec
ted
by re
ed s
witc
h to
ol. W
ith tr
iple
sen
sor d
ata
can
be c
alib
rate
d in
-situ
usi
ng k
nown
di
stan
ce b
etw
een
1 pa
ir of
sen
sors
Max
imum
: 150
0mId
eally
unl
imite
d; b
ut
depe
nds
on
com
pres
sibi
lity o
f met
al
casi
ng an
d cas
ing/
grou
nd
bond
±3m
m(4)
impr
oved
to ab
out
±0.1
mm
at G
roni
gen
(2)
Inte
rval
: ±15
mm
repo
rted
(1) f
or d
oubl
e;±3
.5m
m fo
r trip
le (2
)
Tota
l: ±0
.05m
(2)
(Pro
babl
y up
to 1
20°C
; ty
pica
l for
pro
duct
ion
logg
ing
tool
s.) A
t G
roni
gen
(2) , i
nduc
tion
sens
ors
conn
ecte
d by
in
var m
andr
el to
min
i-m
ize
tem
pera
ture
effe
ct
(Pro
babl
y 70
,000
KN/m
2 m
axim
um ty
pica
l for
pr
oduc
tion
logg
ing
tool
s)
Inst
rum
ent h
ousi
ng
stai
nles
s st
eel.
Casi
ng: lo
w-a
lloy s
teel
, st
anda
rd o
il-w
ell c
asin
g
Ope
rate
s in
cas
ed h
ole.
Acc
essi
ble
hole
requ
ired.
Wor
ks b
est i
n ho
les
wher
e ca
sing
col
lar h
as a
rece
ss to
pr
ovid
e sh
arp
sign
al
(2)
as a
bove
(1) A
llen,
196
0(2
) deL
oos,
197
3(3
) Alle
n, 1
971
(4) A
llen,
196
8
SON
DE-
TYPE
EXT
ENSO
MET
ER,
with
reed
sw
itch
sens
or (l
ower
ed o
n ca
ble)
and
mag
netic
mar
kers
Soil
Inst
rum
ents
;Te
rra T
echn
olog
y;EL
E
Prob
e lo
wer
ed d
own
hole
on
cabl
e.
Whe
n it
pass
es a
ncho
red
mag
netic
m
arke
r, re
ed s
witc
h cl
oses
and
de
tect
ed a
t sur
face
. Dep
th o
f m
arke
r is
leng
th o
f cab
le p
laye
d ou
t, an
d is
mea
sure
d w
ith s
teel
ta
pe
Typi
cal:
100m
Idea
lly u
nlim
ited,
but
de
pend
s on
casi
ng. U
p to
17
% s
train
pos
sibl
e.
±1-2
mm(1
)In
terv
al: 1
-2m
m
repo
rted
(1) ;
Tota
l: ±2
.5m
m re
porte
d fo
r 30m
; ±5m
m e
stim
ated
fo
r 100
m.
Accu
racy
lim
ited
by
stee
l tap
e
(Pro
babl
y up
to 1
20°C
as
abov
e; R
eed
switc
hed
can
tole
rate
up
to 2
00°C
)
(100
0 KN
/m2 e
stim
ated
; ba
sed
on d
epth
rang
e)
Prob
e in
bra
ss o
r st
ainl
ess s
teel
hous
ing.
M
agne
t pro
babl
y Al
nico
. M
ay b
e co
ated
with
ep
oxy(1
)
Ope
rate
s in
hol
e ca
sed
with
non
-m
agne
tic c
asin
g. A
cces
sible
hol
e re
quire
d; M
agne
ts a
ncho
red
to
grou
nd ou
tsid
e cas
ing o
r atta
ched
to
flexi
ble
casin
g ce
men
ted
to g
roun
d.
Mag
nets
may
als
o be
pne
umat
ical
ly
forc
ed in
to g
roun
d.
as a
bove
(1) B
urla
nd, M
oore
, and
Sm
ith, 1
972
(2) M
arsl
and
and
Qua
rterm
an, 1
974
SON
DE-
TYPE
EXT
ENSO
MET
ER,
with
two
reed
sw
itch
sens
ors
and
mag
netic
mar
kers
(low
ered
on
rods
)
Soil
Inst
rum
ents
;Pr
obe
low
ered
dow
n ho
le o
n co
uple
d ro
ds. P
robe
con
sist
s of
two
reed
sw
itche
s sp
aced
0.5
-1.0
m a
part;
m
agne
ts a
lso
spac
ed a
t thi
s de
pth.
D
epth
of m
arke
r det
erm
ined
by
rod
used
to lo
wer
pro
be. D
ista
nce
betw
een
adja
cent
mar
kers
de
term
ined
by
rod
mov
emen
t bet
wee
n up
per r
eed
switc
h de
tect
ing
low
er
mag
net.
Incr
emen
tal r
od tr
avel
m
easu
red
with
mic
rom
eter
30m
est
imat
edTo
tal:
as a
bove
Inte
rval
: 150
-250
mm
±0.0
5mm
±2m
m e
stim
ated
±0,1
mm
cla
imed
by
mfg
.
(50
°C, e
stim
ated
)(3
00KN
/m2 e
stim
ated
ba
sed
on d
epth
)
Stai
nles
s st
eel r
ods;
st
ainl
ess
stee
l hou
sing
As a
bove
; req
uire
s hol
e w
ith m
inim
al
curv
atur
e si
nce
not v
ery
flexi
ble
as a
bove
SON
DE-
TYPE
EXT
ENSO
MET
ER,
with
radi
oact
ive
bulle
t mar
kers
and
2
or 3
gam
ma-
ray
dete
ctor
s
(GAM
MA-
RAY
LO
GG
ER)
Prov
ided
as
a se
rvic
e on
ly; b
y Dre
sser
-Atla
s,
Schl
umbe
rger
, and
ot
hers
Sond
e co
nsis
ts o
f 2 o
r 3 p
robe
s (u
sual
ly ri
gidl
y) c
onne
cted
in
serie
s. S
igna
l is
sent
to s
urfa
ce
whe
n x-ra
y det
ecto
r loca
tes b
ulle
t. D
epth
dete
rmin
ed b
y am
ount
of c
able
pl
ayed
out a
nd ro
tatio
n of
trac
king
w
heel
-(see
cas
ing-
colla
r loc
ator
). D
ista
nce
betw
een
adja
cent
mar
kers
de
term
ined
by
amou
nt o
f cab
le
play
ed o
ut b
etw
een
uppe
r pro
be
dete
ctio
n of u
pper
bulle
t and
low
er
prob
e de
tect
ion
of lo
wer
bul
let.
With
3 d
etec
tors
, can
use
1 p
air
for i
n-si
tu c
alib
ratio
n
1500
mU
nlim
ited
beca
use
bulle
ts o
utsi
de c
asin
g in
form
atio
n
±0.1
mm
Dep
ends
on
logg
ing
rate
; w
orks
bes
t at s
low
rate
(1
.5m
/min
(1) or
less
(4) ).
Accu
racy
prob
ably
high
er
than
for c
asin
g co
llar
loca
tor o
nce
stra
in
exce
eds e
last
ic lim
it of
casi
ng;
Inte
rval
: ±30
mm
erro
r in
2-de
tect
or to
ol(2
) can b
e re
duce
d to
±3m
m e
rror i
n 3-
dete
ctor
tool
(1) ;
Tota
l: ±1
0 to
120
mm
(1)
(200
°C, e
stim
ated
; ty
pica
l for
x-ra
y lo
ggin
g to
ols)
Tool
coo
led
with
dry
ice
(3)
(140
,000
kN
/m2 ;
typi
cal f
or x
-ray
logg
ing
tool
s)
Bulle
ts a
re 1
0µ C
urie
C
esiu
m 1
37(1
) at
Gro
nige
n and
1-6
µ Cur
ie
in J
apan
(4)
Inva
r hou
sing
(1)1
cp
Ope
rate
s in
cas
ed, o
pen
hole
; sin
ce
bulle
ts ar
e sh
ot in
to fo
rmat
ion
with
pe
rfora
ting
gun,
bes
t to
them
in
stal
l bef
ore
casi
ng. O
ther
wis
e,
to p
reve
nt le
akag
e, o
nly
prod
uctio
n zo
ne c
an b
e m
arke
d. M
ay b
e im
poss
ible
to p
lace
bul
lets
in h
ard
form
atio
ns s
uch
as a
nhyd
rite
and
dolo
mite
.(1) C
an in
stal
l fre
e-ha
ngin
g ca
sing
leng
th in
side
co
mpl
eted
bor
ehol
e w
ith R
/A b
ulle
ts
weld
ed a
t kno
wn
inte
rval
s to
use
as
in-s
itu c
alib
ratio
n fo
r too
l. In
Ja
pan,
wel
ded
butto
ns to
pro
duct
ion
casi
ng to
get
com
pact
ion
of c
asin
g as
wel
l as
grou
nd(4
).
If to
ol ca
n be m
odifi
ed to
m
eet g
eoth
erm
al
envi
ronm
ent,
shou
ld b
e ea
sy to
mai
ntai
n si
nce
porta
ble.
Som
e pr
oble
m
may
aris
e if
R/A
bul
lets
ar
e di
slod
ged
or d
iffus
e in
to fo
rmat
ion
(1) d
eLoo
s, 1
973
(2) A
llen,
196
9(3
) Alle
n, 1
977
(4) S
ano,
196
9(5
) Alle
n, 1
971
SON
DE-
TYPE
EXT
ENSO
MET
ER,
with
latc
hing
paw
ls to
det
ect c
asin
g co
llars
Soilt
est;
Sinc
o;
Soil
Inst
rum
ents
; G
eote
stin
g
Whe
n pr
obe
low
ered
dow
n th
roug
h sm
all d
ia,.
coup
ling
into
larg
er
diam
eter
casi
ng, p
awls
will
lock
if pu
lled
upwa
rd a
gain
st s
mal
ler x
-se
ctio
n. D
epth
mea
sure
d on
gr
adua
ted
tape
at t
hese
x-s
ectio
ns
Typi
cal:
100m
Tota
l int
erva
l: 3-
6%
verti
cal s
train
; lim
ited
to a
llow
able
mov
emen
t pe
r cou
plin
g
±1 to
±3m
mIn
terv
al: ±
10m
est
imat
ed
Tota
l: ±4
0mm
est
imat
ed
Best
whe
n ho
le w
ithin
25
° of v
ertic
al
(50
°C, e
stim
ated
)(1
000
kN/m
2 est
imat
ed;
but s
houl
d op
erat
e if
som
e le
akag
e oc
curs
)
Chro
me/
bras
s or
ga
lvan
ized
ste
elRe
quire
s ca
sed
hole
with
te
lesc
opin
g tu
bing
and
col
lars
wh
ich
have
a d
iffer
ent I
.D. f
rom
ca
sing
. Lat
chin
g m
echa
nism
rele
ased
wh
en p
robe
hits
hol
e bo
ttom
, al
low
ing
with
draw
al.
Requ
ires
appl
ied
upw
ard
forc
e at
re
gula
r int
erva
ls to
det
ect c
olla
rs
Tool
has
mov
ing
mec
h-an
ical
par
ts; a
lthou
gh
porta
ble,
may
be
dif-
ficul
t to
mod
ify fo
r ge
othe
rmal
con
ditio
ns
B-3
Guidebook to studies of land subsidence due to ground-water withdrawal PROPERTIES
INSTRUMENT
AVAILABILITY
OPERATING PRINCIPLE
DEPTH RANGE
RANGE OF VERTICLE
DISPLACEMENT
MAN
UFA
CTU
RER
’SSE
NSI
TIVI
TYAC
CU
RAC
YM
AXIM
UM
DO
WN
HO
LE
TEM
PER
ATU
RE:
RAT
ED O
R
(ESI
MAT
ED)
MAX
IMU
M D
OW
NH
OLE
PR
ESSU
RE:
RAT
ED O
R (E
STIM
ATED
)
MAT
ERIA
LC
OM
POSI
TIO
NO
PER
ATIO
N a
nd IN
STAL
LATI
ON
(IMPO
RTA
NT
FEAT
UR
ES)
MAI
NTE
NAN
CE
REQ
UIR
EMEN
TS
& ES
TIM
ATED
SER
VIC
E LI
FESE
LEC
TED
REF
EREN
CES
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith p
endu
lum
and
LVD
T se
nsor
Gal
ileo;
Dam
es a
nd
Moo
reAs
prob
e inc
lines
, pen
dulu
m re
mai
ns
verti
cal.
The
LVD
T m
easu
res
the
disp
lace
men
t of t
he b
otto
m o
f the
pe
ndul
um re
lativ
e to t
he in
stru
men
t ca
se. D
epth
det
erm
ined
by a
mou
nt o
f ca
ble
play
ed o
ut a
t mea
surin
g po
int.
300m
est
imat
ed12
°±1
min
±10
min
est
imat
ed(5
0°C
, est
imat
ed b
ased
on
typi
cal e
lect
roni
cs)
(300
0 KN
/cm
2 , est
imat
ed
base
d on
dep
th)
Prob
ably
stai
nles
s ste
el
hous
ing;
cas
ing
usua
lly
groo
ved
PVC
.
To g
et o
rient
atio
n, m
ust i
nsta
ll in
groo
ved
or s
quar
e ca
sing
, sur
vey
initi
ally
for s
pira
l; fo
r bes
t re
sults
, cas
ing
shou
ld b
e te
le-
scop
ing
if ce
men
ted
or k
eyed
to
surro
undi
ng g
roun
d. C
asin
g m
ay b
e in
serte
d in
side
flex
ible
gro
uted
ca
sing
. Tak
e re
adin
gs a
t int
erva
ls
corre
spon
ding
to to
ol le
ngth
.
Prob
e te
mpo
rary
; if i
t ca
n be
mod
ified
to m
eet
geot
herm
al co
nditi
ons,
it sh
ould
be
easi
ly
mai
ntai
ned.
Sca
ling
and
dist
ortio
n of
cas
ing
grov
es m
ay li
mit
life.
Cas
ing
mat
eria
ls n
ow u
sed
not s
uita
ble
for
geot
herm
al e
nviro
nmen
t.
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith p
endu
lum
and
line
ar
pote
ntio
met
er s
enso
r
Sinc
oAs
prob
e inc
lines
, pen
dulu
m re
mai
ns
verti
cal.
Pend
ulum
con
tact
s re
sist
ance
ele
men
t fix
ed to
cas
e.
Res
ista
nce
varie
s w
ith a
ngle
be
twee
n pe
ndul
um a
nd in
stru
men
t ca
se. D
epth
det
erm
ined
by a
mou
nt o
f ca
ble
play
ed o
ut a
t mea
surin
g po
int.
300m
12° -
25
°3
min
±20
min
est
imat
ed(a
s ab
ove)
1400
KN
/m2
Prob
e ha
s bra
ss ho
usin
g,
casi
ng u
sual
ly a
lum
inum
or
pla
stic
as a
bove
as a
bove
Wils
on, 1
962
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith p
endu
lum
and
ser
vo-
acce
lero
met
er
Terra
-Tec
hnol
ogy;
Geo
-Tes
ting;
Sin
coAs
prob
e inc
lines
, pen
dulu
m re
mai
ns
verti
cal.
This
sys
tem
mea
sure
s fo
rce
requ
ired
to re
turn
pen
dulu
m
to in
itial
alig
nmen
t in
prob
e.
Dep
th de
term
ined
by a
mou
nt o
f cab
le
play
ed o
ut a
t mea
surin
g po
int.
300m
Typi
cal:
25°
45-9
0° a
vaila
ble
±10
sec
±1 m
in re
porte
d (1
)Ty
pica
l: 50
°C, u
p to
90°C
av
aila
ble
Typi
cal:
3500
KN
/m2 u
p to
140
,000
KN
/m2
avai
labl
e
Prob
e ha
s st
ainl
ess
stee
l hou
sing
; whe
el m
ay
be a
lum
inum
, sta
inle
ss
stee
l, or
har
d pl
astic
; ca
ble
case
d in
har
d po
lyur
etha
ne o
r ne
opre
ne.
as a
bove
as a
bove
(1) B
row
nwel
l, Rya
n an
d To
th, 1
971
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith p
endu
lum
and
air
pres
sure
de
vice
Terra
Tech
, de
velo
pmen
tal
As a
bove
exc
ept:
Tilt
mea
sure
d by
pne
umat
ic fo
rce
(air
pres
sure
) req
uire
d to
retu
rn
pend
ulum
to o
rigin
al a
lignm
ent i
n pr
obe.
100m
est
imat
ed±3
5 se
c±3
deg
est
imat
ed(5
0°C
est
imat
ed)
(100
0 KN
/m2
estim
ated
Prob
ably
stai
nles
s ste
el
hous
ing
as a
bove
as a
bove
Dun
nicl
iff, 1
970
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith c
antil
ever
ed p
endu
lum
and
vi
brat
ing
wire
stra
in g
auge
s
Mai
hak;
Tel
emac
; G
eono
r; EL
EC
antil
ever
with
wei
ght a
t uns
uppo
r-te
d en
d be
nds
as p
robe
tilts
. Ben
d-in
g of
can
tilev
er m
easu
red
by v
i-br
atin
g w
ire s
train
gau
ge.D
epth
de
term
ined
by
amou
nt o
f cab
le
play
ed o
ut a
t mea
surin
g po
int.
300m
est
imat
edTy
pica
l: 6-
30°
±30
sec
- ±2
min
±3 to
4 m
in re
porte
d(5
0°C
est
imat
ed b
ased
on
typi
cal e
lect
roni
cs)
(300
0 KN
/m2 , e
stim
ated
ba
sed
on d
epth
)
Prob
ably
stai
nles
s ste
el
hous
ing.
Cas
ing
usua
lly
groo
ved,
PVC
.
as a
bove
as a
bove
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith c
antil
ever
ed p
endu
lum
and
bo
nded
ele
ctric
al re
sist
ance
stra
in
gaug
es
Soil
Inst
rum
ents
: So
iltes
tC
antil
ever
with
wei
ght a
t uns
uppo
r-te
d en
d be
nds
as p
robe
tilts
. Ben
d-in
g of
can
tilev
er m
easu
red
by
elec
trica
l res
ista
nce
stra
in
gaug
es.D
epth
det
erm
ined
by
amou
nt
of c
able
pla
yed
out a
t mea
surin
g po
int.
200m
5° to
30
°±1
5 se
c to
±40
sec
±1 m
in(1
) repo
rted
for
shal
low
dep
ths
(as
abov
e)(2
000
KN/m
2 , est
imat
ed
base
d on
dep
th)
Chro
me
plat
ed b
rass
or
stai
nles
s ste
el ho
usin
g;
neop
rene
shea
thed
cabl
e,
stai
nles
s st
eel w
heel
s.
as a
bove
as a
bove
(1) K
alls
teni
us a
nd
Berg
au, 1
961
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith p
endu
lum
, com
pass
and
cam
era
Sper
ry S
un;
Schl
umbe
rger
As pr
obe i
nclin
es, p
endu
lum
rem
ains
ve
rtica
l. C
amer
a ph
otog
raph
s pe
ndul
um p
ositi
on re
lativ
e to
co
mpa
ss fi
xed
to c
ase.
Dep
th
dete
rmin
ed b
y am
ount
of c
able
pl
ayed
out
at m
easu
ring
poin
t.
Dee
p ho
les
mor
e th
an 6
km2
° to
130
° ava
ilabl
eM
axim
um: 3
15°C
for 5
hrs;
w
ith s
peci
al
inst
rum
enta
tion;
Typi
cal:
175
°C
140,
000
KN/m
2 Pr
obab
ly st
ainl
ess s
teel
ho
usin
g.In
stru
men
t det
erm
ines
bot
h or
ient
atio
n an
d til
t; ca
mer
a op
erat
ed by
timer
; acc
urac
y of d
epth
m
easu
rem
ent a
ssoc
iate
d w
ith a
ngle
m
easu
rem
ent w
ill be
low
unl
ess
used
as
a s
ingl
e-sh
ot d
evic
e.
Prob
e te
mpo
rary
; if c
an
be m
odifi
ed to
mee
t ge
othe
rmal
con
ditio
ns,
shou
ld b
e ea
sily
m
aint
aine
d
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; pe
ndul
um, l
inea
r pot
entio
met
er,
com
pass
and
rota
ry m
otor
East
man
For c
ompa
ss o
rient
atio
n, ro
tary
m
otor
rota
tes
mirr
or u
ntil
indi
-ca
tor f
acin
g no
rth. F
or a
ngle
from
ve
rtica
l as
prob
e til
ts, p
endu
lum
re
mai
ns v
ertic
al. P
endu
lum
con
-ta
cts
resis
tor f
ixed
to c
ase.
R
esis
tanc
e va
ries
with
ang
le
betw
een
pend
ulum
and
inst
rum
ent
case
.
450m
- 54
0mm
ore
than
30
°; ca
n us
ed
at a
ny a
ngle
1°
for t
ilt;
2° f
or
orie
ntat
ion
(50
°C e
stim
ated
)63
00 K
N/m
2Ch
rom
e pl
ated
bro
nze
case
Dete
rmin
es in
clin
atio
n an
d or
ient
atio
n; d
evic
e al
so c
onta
ins
TV c
amer
a
as a
bove
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith g
yro-
com
pass
cam
era,
and
pe
ndul
um
Serv
ice
tool
onl
y; b
y Sp
erry
Sun
, Sc
hlum
berg
er
As pr
obe i
nclin
es, p
endu
lum
rem
ains
ve
rtica
l. C
amer
a ph
otog
raph
s pe
ndul
um p
ositi
on re
lativ
e to
gyr
o-co
mpa
ss, f
ixed
to c
ase.
6.2k
m re
porte
d; m
axim
um
rang
e pr
obab
ly 9
km2°
to 9
0°
±15
min
tilt;
1° t
o 3
° or
ient
atio
n19
0°C
repo
rted,
with
th
erm
al s
hiel
d fo
r up
to
11.5
hrs
.
(112
,000
KN
/m2
estim
ated
, bas
ed o
n de
pth
and
mud
s re
porte
d)
Hous
ing
K-M
onel
Dete
rmin
es in
clin
atio
n an
d or
ient
atio
nas
abo
veO
il and
Gas
Jou
rnal
, 19
71
SON
DE-
TYPE
BO
REH
OLE
INC
LIN
OM
ETER
; w
ith n
eedl
e-po
inte
d pe
ndul
um a
nd
punc
habl
e ch
art
Totc
oas
pro
be in
clin
es p
endu
lum
rem
ains
ve
rtica
l. At
pre
-set
tim
e po
int o
f pe
ndul
um p
unch
ed c
hart
fixed
to
prob
e, gi
ving
incl
inat
ion o
f pro
be.
Dep
th d
eter
min
ed b
y am
ount
of w
ire-
line
play
ed o
ut.
6-10
Km e
stim
ated
7, 1
4, 2
1 de
g8
min
15 m
in e
stim
ated
Spec
ial m
odel
s ava
ilabl
e fo
r war
m(<
150
°C a
nd
hot(<
300
°C e
stim
ated
) ho
les.
(100
,000
KN
/m2
estim
ated
, bas
ed o
n de
pth)
Prob
ably
stai
nles
s ste
el
hous
ing
Mak
e re
adin
g at
one
dep
th o
nly
- gi
ves
tilt o
nly
- not
orie
ntat
ion.
M
ust b
e ret
rieve
d to
dete
rmin
e til
t. Ti
lt si
mpl
y de
term
ined
by
exam
inin
g ch
art w
ith m
agni
fyin
g gl
ass,
will
oper
ate
in a
ny ty
pe o
f hol
e, c
ased
or
unc
ased
.
as a
bove
FIXE
D B
OR
EHO
LE D
EFLE
CTO
MET
ERw
ith c
antile
ver m
ount
ed e
lect
rical
re
sist
ance
stra
in g
auge
sen
sors
Tele
met
rics
Stee
l tub
es a
ncho
red
in h
ole
and
conn
ecte
d to
adj
acen
t tub
es b
y ca
ntile
ver.
Angu
lar m
ovem
ent
betw
een t
wo t
ubes
caus
es ca
ntile
ver
to b
end.
Ben
ding
sen
sed
by s
train
ga
uges
.
54m
with
6m
inte
rval
s be
twee
n ca
ntile
vers
±3 s
ec±2
0 se
c50
°C(5
40 K
N/m
2 est
imat
ed
base
d on
dep
th)
Tube
s ar
e st
ainl
ess
stee
lDe
sign
ed fo
r use
in u
ncas
ed ho
le b
ut
coul
d be
inst
alle
d in
flex
ible
ca
sing
.O
rient
atio
n m
ust b
e de
term
ined
whe
n in
stal
led
Perm
anen
t; m
ay b
e im
poss
ible
to re
cove
r or
repa
ir; e
lect
roni
cs w
ill re
quire
mod
ifica
tion
for
geot
herm
al e
nviro
nmen
t; st
ainl
ess
stee
l hou
sing
may
leak
afte
r sev
eral
ye
ars
serv
ice,
due
to
pitti
ng o
r cor
rosi
on.
FIXE
D B
OR
EHO
LE D
EFLE
CTO
MET
ER
with
indu
ctiv
e se
nsor
Inte
rfels
Stee
l tub
es a
ncho
red
in h
ole
and
conn
ecte
d by
tens
ione
d w
ire.
Posi
tion o
f wire
chan
ges a
s ang
ular
m
ovem
ent b
etw
een
tube
s oc
cur.
Mov
e-m
ent d
etec
ted
by in
duct
ive
sens
ors
54m
with
up
to 8
m
easu
ring
elem
ents
35m
in/e
lem
ent;
rese
ttabl
e±2
to ±
20 s
ec±1
to 3
min
est
imat
ed(5
0°C
est
imat
ed)
(540
KN
/m2 e
stim
ated
ba
sed
on d
epth
)
Prob
ably
stai
nles
s ste
el
hous
ing
as a
bove
as a
bove
FIXE
D B
OR
EHO
LE D
EFLE
CTO
MET
ERw
ith p
endu
lum
, ele
ctric
al c
onta
cts
with
mic
rom
eter
SGI
Pend
ulum
rem
ains
ver
tical
as
prob
e til
ts. W
hen
tilt e
xcee
ds a
pre
set
valu
e, p
endu
lum
has
sw
ung
far
enou
gh to
touc
h el
ectri
cal c
onta
ct
and
com
plet
e ci
rcui
t. M
icro
met
er
can
be tu
rned
from
sur
face
to
defle
ct p
endu
lum
to d
eter
min
e an
gle
10m
est
imat
ed0
- 1 d
eg. t
o se
vera
l de
gree
s(1)
±6 m
in to
±7
sec
± 3
deg
estim
ated
(50
°C e
stim
ated
)(1
00 K
N/m
2 est
imat
ed
base
d on
dep
th)
Prob
ably
stai
nles
s ste
el
hous
ing
Inst
all in
flex
ible
tube
. Det
erm
ine
orie
ntat
ion
whe
n in
stru
men
t in
stal
led.
Req
uire
s m
echa
nica
l co
nnec
tion
betw
een
surfa
ce a
nd
inst
rum
ent
as a
bove
; pro
babl
y no
t su
itabl
e fo
r geo
ther
mal
en
viro
nmen
t
(1) K
alls
teni
us a
nd
Berg
au, 1
961
B-4
Appendix C. List of symbols used in text, part I
Symbol Term______________________________________________________________________________________________
A Cross-sectional area
AP Area of point of sampling spoon
a Area of manometer
b Thickness; effective stress due to buoyant weight of submerged deposits
b’ Thickness of aquitard
C D/R
CC Compression index
CV Coefficient of consolidation
D Depth to compressing beds
dh/dt Rate of subsidence
E Young’s modulus
e Void ratio; e0, initial void ratio
G Specific gravity
H Total subsidence
H0 Initial thickness
h Applied stress; difference in head; head at given elapsed time
ha Average head in aquitard
hC Head in confined system
h0 Head at zero time
hu Head in unconfined system
J Seepage stress
K Hydraulic conductivity
K’ Vertical hydraulic conductivity
L Length of flow
MV Coefficient of volume compressibility
C-1
Guidebook to studies of land subsidence due to ground-water withdrawal
Symbol Term______________________________________________________________________________________________
N Average of N (blows)
n Porosity
p Total stress (geostatic pressure); water level
p’ Effective stress (effective overburden pressure)
pa Applied stress
PO Reference water level
Q Amount of liquid production; quantity of water discharged in unit time
R Radius of stressed system
Ru Ultimate bearing resistance
rs Specific retention
S Storage coefficient; effective stress due to weight of unsaturated deposits
SC Final subsidence
So Sorting coefficient
Ss Specific storage
S’s Specific storage of aquitard (compressible bed)
Ske Component of S attributable to elastic deformation of the aquifer-system skeleton
Sske Component of Ss due to elastic deformation of aquifer-system skeleton
Skv Component of S attributable to inelastic (virgin) deformation, of aquifer-systemskeleton
Sskv Component of Ss due to inelastic (virgin) deformation of aquifer-system skeleton
Ssw Component due to compressibility of water
S’sk Component of specific storage due to compressibility of aquitard
S’skv Skv/b’; b’ is aggregate thickness of aquitards
s Amount of subsidence; drawdown
T Transmissivity; time factor
t time
U Degree of consolidation
Ut Excess pore pressure at time t
UW Pore pressure (fluid pressure or neutral stress)
C-2
Appendix C
Symbol Term______________________________________________________________________________________________
V Flow velocity vector
w Moisture content, per cent of dry weight
wL Liquid limit
wP Plastic limit
Ys Specific yield
z Depth
αke Compressibility of aquifer-system skeleton in elastic range of stress
αkv Compressibility of aquifer-system skeleton in virgin range of stressing
βw Compressibility of water
γ Submerged unit weight
γb Buoyant unit weight of saturated deposits
γd Dry unit weight
γm Moist unit weight
γs Unit weight of solids
γw Unit weight of water
∆p’ Change in effective stress
ν Diffusivity; Poisson’s ratio
τ Time constant
C-3
Appendix D. Glossary, by Laura Carbognin andWorking Group
The purpose of this glossary is to explain the meaning of terms currently recurring in studieson land subsidence due to ground-water withdrawals. Because this volume is for readers withdiverse backgrounds and for interested untrained personnel, the definitions given here aresimplified. For a more detailed explanation, the bibliography suggests some books which willhelp the reader.
AQUICLUDE
An areally extensive body of saturated but relatively impermeable material that does not yieldappreciable quantities of water to wells. Aquicludes constitute boundaries of aquifer flowsystems; term is synonymous with confining bed.
AQUIFER
An areally extensive body of saturated permeable material that will yield significant quantitiesof water to wells and springs. An aquifer includes the unsaturated part of the permeable body.Aquifers may be classed as unconfined or confined, depending upon the presence or absence of awater table. An aquifer may also be called a water-bearing stratum. Unconsolidated alluvialdeposits of sand and gravel, porous sandstones, or fractured limestones are examples ofwater-bearing formations
AQUIFER SYSTEM
A heterogeneous body of interbedded permeable and poorly permeable layers that functionsregionally as a water-yielding hydraulic unit. It comprises two or more aquifers (permeableformations) separated by laterally discontinuous aquitards that locally impede ground-watermovement but do not greatly affect the overall hydraulic continuity of the system.
AQUITARD
A saturated, but poorly permeable, bed that locally impedes ground-water movement and does notyield water freely to wells, but which may transmit appreciable water, to or from adjacentaquifers.
ARTESIAN
The term artesian derives from Artois (Lat. Artesium), a northern province of France wherenaturally flowing wells were drilled in 1750. Today the term artesian is applied to any welltapping a pressure aquifer or simply to the aquifer itself. Artesian is synonymous withconfined.
ARTESIAN AQUIFER
An aquifer in which the water level rises above the base of the upper confining bed whenpenetrated by a well. In recent years artesian aquifer has been used as a synonym for confinedaquifer.
D-1
Guidebook to studies of land subsidence due to ground-water withdrawal
BENCH MARK
A relatively permanent mark, natural or artificial, furnishing a survey point at a knownelevation in relation to an adopted datum. Bench marks, or marked points, connected by preciseleveling, constitute the control of land-surface settlement.
COEFFICIENT OF COMPRESSIBILITY (L2F-l)
Compressibility is the aptitude of the soil to be deformed. It is expressed by means of acoefficient which is the ratio between a void ratio decrease from eo to e and an increase ineffective stress. The value av = e0-e∆p represents the coefficient of compressibility for therange p0 to p0 + p. Units usually are cm
2kg-1.
COEFFICIENT OF VOLUME COMPRESSIBILITY (L2F-l)
The compression of a clay (aquitard) per unit of original thickness, due to a unit increase ofeffective stress, in the load range exceeding preconsolidation stress. It is expressed by theequation
in which e0 is the initial void ratio. Units usually are cm2 kg-l.
COMPACTION
A decrease in the volume of a mass of sediments from any cause. In this guidebook, compaction isdefined as the decrease in the thickness of sediments, as a result of an increase in verticalcompressive stress, and is synonymous with "one-dimensional consolidation," as used byengineers. The term compaction is applied both to the process and to the measured change inthickness.In thick fine-grained beds, compaction is a delayed process involving the slow escape of porewater and the gradual transfer of stress from neutral to effective. Until sufficient time haspassed for excess pore pressure to decrease to zero, measured values of compaction aretransient.
COMPACTION, RESIDUAL
Compaction that would occur ultimately if a given increase in applied stress were maintaineduntil steady-state pore pressures were achieved, but had not occurred as of a specified timebecause excess pore pressures still existed in beds of low diffusivity in the compacting system.It can also be defined as the difference between (1) the amount of compaction that will occurultimately for a given increase in applied stress, and (2) that which has occurred at aspecified time.
COMPACTION, SPECIFIC (L3F-l)
The decrease in thickness of deposits, per unit of increase in applied stress, during a specifictime period.
CONE OF DEPRESSION
A cone of depression in the water table, developed around a pumping well and extendingthroughout the area of influence of a well (also see drawdown). For an artesian aquifer, thiscan be called the "cone of pressure relief" (Tolman, 1937).
mv
av1 e0+---------=
D-2
Appendix D
CONFINED AQUIFER
Same as artesian aquifer.
CONSOLIDATION
The gradual reduction in the water content (void ratio) of a saturated soil, as a result of anincrease in the pressure acting on it, because of the addition of overlying sediments or theapplication of an external load. A laboratory test called a one-dimensional consolidation test(odometric test), is performed on soil samples to evaluate consolidation. From such a test thecoefficient of consolidation, cv, usually reported in cm
2sec-1, is calculated as the ratio
where K is the hydraulic conductivity, mv is the coefficient of volume compressibility, and γw isthe unit weight of water. The theory of consolidation, developed by Terzaghi, leads to arelation between degree of consolidation and time:
U%
In this expression U is the degree of consolidation, that is, the percentage of totalconsolidation occurring in some time t; cv is the coefficient of consolidation; and H is half ofthe sample’s thickness when the odometric test is performed.
DRAWDOWN
As water is withdrawn from an aquifer by a pumped well, the ground-water level is lowered.Drawdown is the distance the water table or pressure surface is lowered at a given point (seealso cone of depression).
EXTENSOMETER
An instrument used for measuring vertical deformation of fine-grained beds in the subsoil understress. Vertical extensometers commonly are installed when land subsidence follows ground-waterwithdrawal. Extensometers also are used to measure small horizontal displacements.
HEAD, HYDRAULIC, OR STATIC
The static head is the height, referred to a standard datum, of the surface of a column of waterthat can be supported by the static pressure at a given point. The static head is the sum of theelevation head and the pressure head.
HYDRAULIC CONDUCTIVITY, K (LT-1)
If a porous medium is isotropic and the fluid is homogeneous, the hydraulic conductivity of themedium is the volume of water at the existing kinematic viscosity that will move in unit timeunder a unit hydraulic gradient through a unit area measured at right angles to the direction offlow. In the metric system it may be expressed in cm sec-1; in English units it may be expressedin feet day-1 (see also permeability).
cvK 1mvγ w---------=
cvt
H2
------=
D-3
Guidebook to studies of land subsidence due to ground-water withdrawal
HYDRAULIC GRADIENT
The change in static head per unit of distance in the direction of the maximum rate of decreasein head if not specified. If different, direction is specified.
HYDROCOMPACTION
The process of volume decrease and density increase that occurs when moisture-deficient depositscompact as they are wetted for the first time since burial. This type of land settlement hasalso been called "shallow subsidence."
LAND SUBSIDENCE
Sinking or settlement of the land surface, due to diverse causes and generally occurring on alarge scale. Usually the term refers to the vertical downward movement of the land surfacealthough small-scale horizontal movements may be present. The term does not include landslideswhich have large-scale horizontal displacements, or settlement of artificial fills.
PERMEABILITY
The capacity of rock or soil to transmit fluid under the combined action of gravity andpressure. Permeability is expressed as the velocity with which water, under the influence of agiven difference in head, passes through a porous medium having a certain cross section andthickness. Permeability is dependent on the size and shape of the pores of the porous medium andit can be reduced by compaction (see also hydraulic conductivity).
PHREATIC AQUIFER
Same as unconfined aquifer.
PHREATIC SURFACE
Same as water table.
PIEZOMETRIC SURFACE
An imaginary surface coinciding with the head of the water in an aquifer. (Also seepotentiometric surface.)
POTENTIOMETRIC SURFACE
A surface which represents the static head. As related to an aquifer, it is defined by thelevels to which water will rise in tightly cased wells (USGS) Also called piezometric surface inmany countries.
REBOUND
An upward movement of soil as a consequence of a decrease in effective stress. In fine-grainedsoils, rebound is usually much less than the amount of compaction, since the latter is mostlyirreversible.
D-4
Appendix D
RECOVERY
The water-level rise in a well occurring upon the cessation of discharge from that well or anearby well.
STRESS, APPLIED (FL-2)
The downward stress imposed at an aquifer boundary. It differs from effective stress in that itdefines only the external stress tending to compact a deposit rather than the grain-to-grainstress at any depth within a compacting deposit.
STRESS, EFFECTIVE (FL-2)
Stress (pressure) that is borne by and transmitted through the grain-to-grain contacts of adeposit, and thus affects its porosity or void ratio and other physical properties. In one-dimensional compression, effective stress is the average grain-to-grain load per unit area in aplane normal to the applied stress. At any given depth, the effective stress is the weight (perunit area) of sediments and moisture above the water table, plus the submerged weight (per unitarea) of sediments between the water table and the specified depth, plus or minus the seepagestress (hydrodynamic drag) produced by downward or upward components, respectively, of watermovement through the saturated sediments above the specified depth. Thus, effective stress maybe defined as the algebraic sum of the two body stresses, gravitational stress and seepagestress. Effective stress may also be defined as the difference between geostatic and neutralstress.
STRESS, GEOSTATIC (FL-2)
The total load per unit area of sediments and water above some plane of reference. It is the sumof (1) the effective stress and (2) the neutral stress.
STRESS, NEUTRAL (FL-2)
Fluid pressure exerted equally in all directions at a point in a saturated deposit by the headof water. Neutral pressure is transmitted to the base of the deposit through the pore water, anddoes not have a measurable, influence on the void ratio or on any other mechanical property ofthe deposits.
STRESS, PRECONSOLIDATION.(FL-2)
The maximum antecedent effective stress to which a deposit has been subjected, and which it canwithstand without undergoing additional permanent deformation. Stress changes in the range lessthan the preconsolidation stress produce elastic deformations of small magnitude. In fine-grained materials, stress increases beyond the preconsolidation stress produce much largerdeformations that are principally inelastic (nonrecoverable).
STRESS, SEEPAGE (FL-2)
When water flows through a porous medium, force is transferred from the water to the medium byviscous friction. The force transferred to the medium is equal to the loss of hydraulic head.This force, called the seepage force, is exerted in the direction of flow.
SUBSIDENCE/HEAD-DECLINE RATIO
The ratio between land subsidence and hydraulic head decline in the coarse-grained beds of thecompacting aquifer system.
D-5
Guidebook to studies of land subsidence due to ground-water withdrawal
UNCONFINED AQUIFER
A geologic formation of permeable material that has a water table as the upper surface.
WATER TABLE
The upper surface of the zone of saturation in a phreatic aquifer in which the pressure isatmospheric.
WELL, ARTESIAN
A well that takes water from a pressure water body.
REFERENCES
AMERICAN SOCIETY FOR TESTING AND MATERIAL. 1980. Standard definitions of terms and symbolsrelating to soil and rock mechanics. ASTM C.653-80, p. 29.
CHOW, V. T. 1964. Handbook of applied hydrology, Ch. 13. New York, McGraw-Hill, 55 p.
KEZDI, A. 1974. Handbook of soil mechanics. Vol. 1, Soil physics. New York, Elsevier, 294 P.
LOFGREN, B. E., and KLAUSING, R. L. 1969. Land subsidence due to ground-water withdrawal,Tulare-Wasco area, California. U.S. Geological Survey water-supply paper 1988, 21 p.
MEINZER, O. E. 1923. Outline of ground-water hydrology with definitions. U.S. Geological Surveywater-supply paper 494, 71 p.
POLAND, J. F., LOFGREN, B. E., and RILEY, F. S. 1972. Glossary of selected terms useful instudies of the mechanics of aquifer systems and land subsidence due to fluid withdrawal. U.S.Geological Survey Water-Supply Paper 2025, 9 p.
PROKOPOVICH, N. P. 1963. Hydrocompaction of soils along the San Luis Canal alignment, westernFresno County, California. In Abstracts for 1962. Geol. Soc. America spec. paper 76, p. 70.
TERZAGHI, K., and PECK, R. B. 1967. Soil mechanics in engineering practice, 2nd ed. New York,John Wiley, 729 p.
TODD, D. K. 1959. Hydrology. New York, John Wiley, 336 p.
TOLMAN, C. F. 1937. Ground water. New York, McGraw-Hill. 593 p.
UNITED NATIONS EDUCATIONAL, SCIENTIFIC AND CULTURAL ORGANIZATION. 1978. International glossaryof hydrology, 2nd ed., WMO/UNESCO.
D-6
Appendix E. Metric conversion tableMultiply inch-pound unit By To obtain metric unit
inch 25.4 millimetre (mm)
foot (ft) 0.3048 metre (m)
foot per mile (ft/mi) 0.1894 metre per kilometre (m/km)
mile (mi) 1.609 kilometre (km).
pound ----------------------------- 0.45 ---- kilogram (kg)
square foot (ft2) 0.0929 square metre (m2)
square mile (mi2) 2.590 square kilometre (km2)
acre 0.405 hectare (ha)
acre-foot (acre-ft) 1,233 cubic metre (m3)
gallon (gal) ---------------------- 3.785 ---- litre (l) 0.003785 cubic metre(m3)
cubic foot (ft3) 0.0283 cubic metre (m3)
acre-foot per square mile (acre-ft/mi2) 476 cubic metre per square kilometre (m3/)km2)
gallon per minute (gal/min) 6.309xlO-5 cubic metre per second (m3/s)
cubic foot per second per square 0.0109 cubic metre per second per square kilometre mile [(ft3/s)/mi2] [(m3/s)/km2]
ft per year (ft/yr) --------------- 9.7xlO-7 --- centimetres per second (cm/s)
gallon per day per square foot (gal/d/ft2) 4.716xlO-5 centimetre per second (cm/s)
ton (short) 0.9072 metric ton (t)
gallon per day per foot (gal/d/ft) 1.433xl0-3 square centimetre per second (cm2/s)
pound per cubic foot (lb/ft3) 16.05 kilogram per cubic metre (kg/m3)
pounds per square inch (psi) 0.07 kilograms per square centimetre (kg/cm2)
E-1
Guidebook to studies of land subsidence due to ground-water withdrawal
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