茅口灰岩单轴压缩条件下的流变特性试验研究

Experimental Study on the Rheological Properties of Maokou Limestone under Uniaxial Compression

取重庆北碚车站隧道茅口灰岩,根据现场岩层覆盖厚度及其茅口灰岩容重,取单轴压缩应力为6 MPa,采用MTS815多功能岩石试验机对岩样进行24 h单轴压缩蠕变试验,得到岩石轴向应变-时间曲线。分析岩石应变-时间曲线,发现茅口灰岩具有弹性-弹粘性之流变特性,与Poyting-Thomson model相似。用Origin软件对流变试验数据用Poyting-Thomson model方程进行拟合,得到低应力下流变拟合曲线,该拟合曲线能较好反应试验数据。因此,Poyting-Thomson model能较好反应茅口灰岩流变特性。最后求出了茅口灰岩低应力作用下流变模型各项参数。

Maokou limestone is taken from the tunnel in Chongqing BeiBei Station, and according to the rock cover thickness and Maokou limestone bulk density, uniaxial compression creep test of Maokou limestone sample is conducted by MTS815 multi-function rock testing machine under 6 MPa for 24 h, and the strain-time curve is obtained. The strain-time curve is analyzed, and it is found that the limestone has the rheological characteristics of elastic-elasticoviscosity, which is similar to Poyting-Thomson model. The rheological experimental data is fitted through Poyting-Thomson model equation by Origin software, and the rheological fitting curve under low stress level is obtained, which better reflects the test data. It is concluded that Poyting-Thomson model can reflect the rheological properties of Maokou limestone. Finally the parameters of theological models of Maokou limestone under low stress level are found out.