深部灰岩三轴蠕变特性实验研究

An Experimental Study of Deep Limestone Triaxial Creep Behavior

采用MTS815岩石材料力学试验机,在温度28℃条件下,对重庆市万盛区某煤矿深部掘进巷道灰岩进行了三轴蠕变试验,对不同偏应力水平下该巷道灰岩的蠕变特性进行了分析。结果表明,蠕变试验的曲线显示该灰岩蠕变具有非线性特征,其蠕变特性随着围压的增加而更加明显。对深部灰岩的蠕变模型进行初步探讨,回归得出深部灰岩在不同应力水平下蠕变应变随时间变化的Burgers蠕变方程。分析表明,Burgers模型能较好地反映该深部灰岩的蠕变规律。该模型所确定的本构关系可以作为该深部灰岩蠕变本构模型来预测其蠕变发展。

MTS815 rock material mechanics tester was used at 28℃ to examine the triaxial creep behaviour of deep limestone which was sampled from a drifting tunnel of a deep mine in Wansheng district of Chongqing City. Its creep behaviour was analyzed at different deviatoric stress levels. Results show that the limestone creep experimental curves present nonlinear characteristics,and that becomes more evident along with the confining pressure increase. Through a preliminary study of the creep model,Burgers creep equation describing the relation between creep strain and time at different stress levels was obtained by regression. Results of analyzing the fitting relevant parameters show that the Burgers model reflects the deep limestone creep behavior better. The constitutive relation identified by Burgers model may be used as creep constitutive model of deep limestone to predict its creep development.