PERMFILE41761

• Permit No: M1999002
• IBM Index Class Name: Permit File
• Doc Date: 6/18/1999
• Doc Name: OBJECTORS EXHIBITS
• Media Type: D
• Archive: No

Analyfita! Methods • .
RADIAL DISTANCE FROM CENTERLINE OF CAYITYs (FT)
O
o (--0
a 1
0
a
1. t)
2.0
Z
W
U
~ 3.0
o.
N
O
W
U
~ 4.0
N
J
4
U
r
~ 5.0
W
6.0
Figure 5. Vertical subsidence profiles.
Both the "no•tension" analysis and the possibility of
slip along bedding planes were incorporated into a finite
element program for the analysis of axisymmetric elastic
solids. This program was utilized for anal} zing selected
case histories where subsidence records were available to
enable a comparison to be made with [he analytical pre-
dictions.
ANALYSIS OF CASE HISTORIES
As discussed above, methods of analyses incorporating
the possibility of slippage along bedding planes offer a
promising approach to the prediction ofsubsidence. Two
case histories where field measurements were available
were analyzed. The geological conditions, the approxi-
mate cavity size and location, and the observed subsidence
for the two case studies are briefly described in the follow-
ing paragraphs.

107
N
Case I
Geological conditror:s The salt zone called Syracuse
salt averages (10 feet in thickness and is at an average
depth of 2270 fee[ below the surface. It is composed of
three beds: an upper salt bed 10 feet to 20 feet in thickness,
an intermediate shale zone approximately 40 feet thick,
and a lower salt bed averaging 50 feet in thickness. The
Syracuse salt is overlain by approximately 500 feet of
upper Silurian sedimentary rocks consisting of shaley to
massive anhydrite, dolomite, and limestone with some
interbedded shale. The Silurian rocks are overlain in turn
by 1660 feet of Devonian sedimentary rocks. The lower
140 feet comprises the Onondaga limestone. The rest con-
sists primarily of black shales with some interbedded
Baggy sandstone and occasional thin limestone beds. The
idealized rock profile with assumed rock properties based
on information from another location is shown in Figure
6. There was no information from which the number and
too 200 300 400 500 600 700 800