Creep Tests Of Model Stone Heap

The dam settlement upon completion causes the stress redistribution within the dam, leading to cracks appear on the concrete-faced. The safety operation of dam is affected, so at the stage of design the creep of rockfill must be considered. Currently, the researches can not reflect the character of rockfill creep perfectly on the aspect of creep mechanism, creep model, and numerical stimulation calculation. Therefore, through the laboratory creep tests, the creep laws, creep mechanism and creep influencing factors are studied. The main research work is carried out as follows:The rockfill of Shangzhai reservoirs and Lianghekou hydropower were tested, using the SR-4large high-pressure triaxial creep apparatus. The single stage loading and the same confining pressure loading were adopted respectively. Base on the achievements of scholars, the test duration in every stress state was7days, and the point of an hour after test beginning was used as the boundary between the elasticoplastic strain and the creep.The total strain, creep, and creep rate of rockfill at the two different loading conditions, showed similar laws. The deformation stabilization time of rockfill and the total strain increased with the increase of stress level. Both the creep strain and the creep rate of the rockfills followed the linear relationship with the time in a double logarithmic coordinate. At the same confining pressure, creep rate got larger with the increase of the stress level. As the confining pressure increased, the differences of axial creep rate at different stress levels reduced. At the same confining pressure, the volume creep rate at different stress level was similar.According to the creep test data of Shangzhai mian rockfill and Lianghekou mixture, the power function creep expressions were got, and then the creep mechanism was analyzed. The results showed that the stress level was the major factor of the axial stain, and the confining pressure was the major factor of volume stain.The influences on the power function creep expression were discussed from two aspects: the stress level and the confining pressure. To the single stage loading test, the axial initial creep got greater with the increase of stress level, and the axial creep exponent got smaller with the increase of the confining. There did not get the uniform rules to the volume initial creep, but the volume creep exponent got smaller with the increase of the confining. To the same confining pressure loading test, the axial initial creep also got greater with the increase of stress level, and it can be described with exponent function. The axial creep exponent increased parabolically with the confining pressure. As the confining increased, both the volume initial creep and the volume exponent increased parabolically. But the parabola the one was going downwards, the other one upwards. Finally, the power function creep model which included eight parameters was proposed, applying to the same confining pressure loading test. Using the creep model, the rockfill of Lianghekou fitting curves was got. The results showed that the model can accurately describe the rockfill creep.