基于岩体层理特性的非线性抗剪强度准则研究

对湖南湘西雀儿溪隧道中的层状砂岩开展了室内三轴压缩试验.结果表明,因微层理面的影响,该砂岩表现出较强的各向异性强度特性,岩体的破坏存在沿层理面的滑移破坏和非滑移破坏(含斜穿层理面的剪切破坏、基岩破坏及二者的复合破坏)两种模式.针对该砂岩的破坏特征,提出了一种反映其强度特性的非线性破坏准则,该准则对两种破坏模式采用不同的方法进行描述.采用该破坏准则预测层状砂岩的破坏强度,预测结果与试验数据吻合较好.采用该准则对其他不同类型层状岩体的强度进行预测,也获得了较好的结果.

Research on Non-linear Shear Strength Criterion for Layered Rock Mass with Micro-discontinuity

Tri-axial compression tests are carried out on the layered sandstone specimens taken from the QEX Tunnel located in Xiangxi of Hunan. The results show that the strength of the rock is obviously anisotropic and there are two distinct failure modes， i.e.， one is the failure caused by sliding along the discontinuity and the other is non-sliding failure mode in which fracturing of rock material， fracturing across the discontinuity and the mixed mode of the above. Then a non-linear failure criterion for the layered sandstone is proposed to reflect different failure modes using different methods. Performance of the failure criterion is tested for validation against tri-axial compression tests data for the layered sandstone specimens. It shows that predicted values are in good agreement with experimental test data. The applicability of the failure criterion is also examined using the published experimental data of various types of layered rock mass.