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(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
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.
a. General. The resilient modulus of cohesionless soils MR is dependent upon the magnitude
of the confining pressure F3 and is nearly independent of the magnitude of the repeated axial
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
(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
(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.