UFC 3-260-02

30 June 2001

(6) At the completion of the loading, reduce the chamber pressure to zero. Remove the

chamber LVDTs and load cell. Use the entire specimen for the purpose of determining the moisture

content.

c. The results of the resilience tests can be presented in the form of a summary table, such

as Table L-1, and graphically as is shown in Figure L-4 for the resilient modulus.

L-9. RESILIENCE TESTING OF COHESIONLESS SOILS.

stress. Therefore, it is necessary to test cohesionless materials over a range of confining and axial

stresses. (The confining pressure is equal to the chamber pressure less the back pressure for

saturated specimens). The following procedure should be used for this type of test:

(1) Use confining pressures of 0.034, 0.069, 0.103, and 0.138 MPa (5, 10, 15, and

20 psi) at each confining pressure, and test at five values of the principal stress difference

corresponding to multiples (1, 2, 3, 4) of the cell pressure.

(2) Before beginning to record deformations, apply a series of conditioning stresses to the

material to eliminate initial loading effects. The greatest amount of volume change occurs during

the application of the conditioning stresses. Simulation of field conditions suggest that drainage of

saturated specimens should be permitted during the application of these loads but that the test

loading (beginning in step 6 below) should be conducted in an undrained state.

(3) Set the axial load generator to apply a deviator stress of 0.069 MPa (10 psi) (i.e., a

stress ratio equal to 3). Activate the load generator and apply 200 repetitions of this load. Stop

the loading.

(4) Set the axial load generator to apply a deviator stress of 0.138 MPa (20 psi) (i.e., a

stress ratio equal to 5). Activate the load generator and apply 200 repetitions of this load. Stop

the loading.

(5) Repeat as in step 4 above maintaining a stress ratio equal to 6 and using the following

order and magnitude of confining pressures: 0.069, 0.138, 0.069, 0.034, 0.021, and

0.0069 MPa (10, 20, 10, 5, 3, and 1 psi).

(6) Begin the record test using a confining pressure of 0.0069 MPA (1 psi) and an equal

value of deviator stress. Record the resilient deformation after 200 repetitions. Increase the

deviator stress to twice the confining pressure and record the resilient deformation after

200 repetitions. Repeat until a deviator stress of four times the confining pressure is reached

(stress ratio of 5).

(7) Repeat as in step 6 above for each value of confining pressure.

(8) When the test is completed, decrease the back pressure to zero, reduce the chamber

pressure to zero, and dismantle the cell. Remove the LVDT clamps, etc. Remove the soil

specimen, and use the entire amount of soil to determine the moisture content.

L-10

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