TM 5-809-12/AFM 88-3, Chap. 15
Table 4-1. Typical values of modulus of subgrade reaction
Modulus of Subgrade Reaction, k, in lb/in3
for Moisture Contents of
1
5
9
13
17
21
25
to
to
to
to
to
to
to
Over
4%
8%
12%
16%
20%
24%
28%
29%
Types of Materials
Silts and clays
--
175
150
125
100
75
50
25
Liquid limit > 50
(OH, CH, MH)
Silts and clays
--
200
175
150
125
100
75
50
Liquid limit < 50
(OL, CL, ML)
Silty and clayey
300
250
225
200
150
--
--
--
sands (SM & SC)
Gravelly sands
300+
300
250
--
--
--
--
--
(SW & SP)
Silty and clayey
300+
300+
300
250
--
--
--
--
gravels (GM & GC)
Gravel and sandy
300+
300+
--
--
--
--
--
--
gravels (GW & GP)
NOTE: k values shown are typical for materials having dry densities
equal to 90 to 95 percent of the maximum CE 55 density. For materials
having dry densities less than 90 percent of maximum CE 55 density,
values should be reduced by 50 lb/in3, except that a k of 25 lb/in3 will
be the minimum used for design.
4-2
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