含水砂岩三轴蠕变力学特性试验研究

巷道顶板在水的作用下具有较强的蠕滑特性,对矿井开挖与生产造成巨大威胁。采用YSJ-01-00岩石三轴流变试验机开展巷道顶板砂岩三轴压缩蠕变试验,研究砂岩在不同含水条件下的蠕变力学特性。试验结果表明:①随着饱水时间的增长和应力水平的提高,瞬时应变和蠕变量都呈递增趋势;②随着含水状态的增强,初始蠕变速率和稳态蠕变速率都逐渐增大,稳态蠕变速率与应力水平呈幂函数关系;③对比分析2种不同的长期强度求取方法,天然状态、饱水1 d和饱水5 d条件下砂岩的长期强度分别为其瞬时强度的64.12%,62.08%,59.34%,砂岩在水的作用下长期强度衰减加剧。

Experimental Study on Triaxial Creep Mechanical Behavior of Water-bearing Sandstone

The roof of roadway in mine has strong creep characteristics under the action of water, posing great threat to mine excavation and production. In this research we investigated the creep mechanical behavior of sandstone in different water-bearing conditions through triaxial rheological compression test. Test results showed that: (1) with the increase of water-saturation time and the climbing of stress level, instantaneous strain and creep both increased. (2) With the enhancement of water-bearing state, the initial creep rate and steady-state creep rate gradually increased, and the steady-state creep rate was in a power function relationship with the stress level.(3) By comparing two different long-term strength methods, we found that the long-term strength of sandstone under conditions of natural state, water-saturated for 1 day, and water-saturated for 5 days was only 64.12%, 62.08% and 59.34% of its instantaneous strength, respectively,and the long-term strength attenuation aggravated under the action of water.