Environmental Engineering Reference
In-Depth Information
N
0
5
2'
Miles
3'
4'
(Baytown)
(Houston)
(South Houston)
Brazoria CO.
FIGURE 10.1
Surface faulting and cumulative subsidence (in ft) in the Houston area between 1906 and 1964. (From Castle,
R.O. and Youd, T.L.,
Bull. Assoc. Eng. Geol.,
9, 1972. With permission.)
Long
point
fault
Piney
point
fault
W
E
0
0
50
0.5
1943
1.0
100
1.5
150
1954
2.0
200
Water level decline
Surface subsidence
2.5
250
1964
3.0
300
5mi
0
FIGURE 10.2
Profiles of subsidence and groundwater decline along a section trending due west from Houston. (From Castle,
R.O. and Youd, T.L.,
Bull. Assoc. Eng. Geol.,
9, 1972. With permission.)
volcanic clay, which overlie a thick deposit of compact sand and gravel. As shown in the
section given in
Figure 7.60,
the soils to depths of about 33 m are very soft to medium-stiff
clays. Void ratios as high as 13 and water contents as high as 400% indicate the very high
compressibility of the soils (see
Figure 3.81a).
The clays are interbedded with thin sand
layers, and thick sand strata are found at depths of 33, 45, and 73 m. Prior to the 1930s,
groundwater beneath the city was recharged naturally.
