Research on creep damage model of coal and rock mass around hole with different moisture contents

Abstract

In order to explore the influence of water on the creep characteristics of coal and rock mass around the holes, the square samples with holes and different moisture contents were prepared, and the staged loading creep failure test was carried out to obtain the creep curves during the creep loading process of the samples; based on the improved Nishihara model, the damage variable Dw and the aging damage variable Dt two factors are introduced to establish the creep model of coal and rock mass around the hole under different water content conditions; the rationality of creep model was verified by comparing the test results with the calculated values of the model. The research results show that under the same stress level, the time for all samples to enter the stable creep stage is about 1 hour, but the axial strain of the dry sample is small, and the time to reach the accelerated creep stage is also higher, indicating that water has physical erosion and softening effect on coal and rock mass. There is an exponential correlation between the established creep model parameters and the water content. The theoretical curve of the model is in good agreement with the experimental data curve.

Keywords

• water content
• coal and rock mass
• creep test
• improved nishihara model
• creep model