Experimental study on effect of graded loading rate on creep characteristics of anthracite

Abstract

In order to study the effect of graded loading rate on creep characteristics of anthracite, the effects of graded loading rate and stress level on instantaneous strain, creep strain and creep rate of coal samples were analyzed by triaxial creep tests of anthracite under four different graded loading rates. The results show that at the same stress level, the higher the graded loading rate is, the smaller the instantaneous strain is and the larger the creep strain is, but the increasing trend of creep strain gradually slows down; at the same loading rate, with the increase of the creep stress level, the instantaneous strain of coal samples shows an overall decreasing trend of rapidly decreasing-slowly decreasing-increasing, while the creep strain of coal samples shows an overall increasing trend of basically unchanged-slowly increasing-rapidly increasing; the change process of creep rate can be divided into three stages: rapid decay, slow decay and stability, at the same stress level, the higher the graded loading rate is, the higher the maximum creep rate is, and the faster the creep rate decays.

Keywords

• graded loading rate
• anthracite
• creep
• instantaneous strain
• creep strain
• creep rate