考虑围压效应的非线性剪切强度参数模型

Nonlinear Shear Strength Parameter Model Considering the Effect of Confining Pressure

随着深部岩石工程的发展,围压对岩石强度的影响变得不可忽视,开展应力对岩石力学特性参数的研究,对评价深部岩石工程的稳定性具有重要的理论和工程意义。为了揭示深部岩石剪切强度参数的非线性特征,基于花岗岩三轴试验数据库,开展围压对剪切强度参数的影响规律研究,主要结论如下:(1)岩石的内聚力c随着围压的增大而增大,内摩擦角?随着围压的增大而减小;(2)建立了不同围压条件下的剪切强度参数c和?数据库,提出了考虑围压效应的非线性剪切强度参数模型;(3)误差分析结果表明,在没有三轴试验数据的情况下,非线性剪切强度模型有较好的岩石强度预测能力,90%的岩石强度误差小于20%。

With the development of deep rock engineering, the influence of confining pressure on rock strength cannot be ignored. The study of stress on rock mechanics characteristic parameters has important theoretical and engineering significance for evaluating the stability of deep rock engineering. In order to reveal the non-linear characteristics of the shear strength parameters of deep rocks, based on the granite triaxial test database, research on the influence of confining pressure on the shear strength parameters is carried out. The main conclusions are as follows:(1) The cohesion c of the rock increases and the internal friction angle ? decreases with the increase of confining stress;(2) A database of shear strength parameters c and ? under different confining stress conditions is established, and a nonlinear shear strength parameter model considering the effect of confining pressure is proposed;(3) Error analysis results show that in the absence of triaxial test data, the nonlinear shear strength parameter model has a good ability to predict the strength of rocks, and the error of 90% of the rock strength is less than 20%.