柱状节理岩体压缩破坏过程模拟及机制分析

 将柱状节理岩体整体考虑为一种广义宏观复合材料是一种行之有效的研究方法，为此建立复合型多弱面软化模型，采用VC++语言成功开发并嵌入FLAC3D程序。以白鹤滩水电站的地质条件为研究背景，对柱状节理岩体进行单轴压缩和三轴压缩的模拟计算，分析不同节理面倾角和倾向的试块破坏过程，得出各种情况下破裂面分布和破坏形态，并总结具有普遍意义的破坏规律。通过三轴试验还得到在处于合适的地应力条件时，柱状节理岩体整体强度及节理面之间的咬合力均较高的结论，与现场勘测结果一致。同时，研究压缩破坏过程中外载和变形的规律、塑性破坏区的产生、破裂区的分布和发展以及能量的耗散等，从多方面对柱状节理岩体的破坏机制进行探讨，以便更好了解该类岩体的力学特性。

SIMULATION OF COMPRESSIVE FAILURE PROCESS OF COLUMNAR JOINTED ROCK MASS AND ITS FAILURE MECHANISM ANALYSIS

The columnar jointed rock mass is considered as a macroscopic composite material in a broader sense. A softening model of mixed multi-weakness planes is developed. Based on the second developing platform of constitutive model in FLAC3D，the mixed softening model has been successfully established and embedded. Taking the geological conditions of Baihetan Hydropower Station as research background，uniaxial and triaxial compressions of columnar jointed rock mass are simulated；and then the failure processes of test blocks with different dip angles and directions are analyzed. The distribution of fractured planes and the failure modes are achieved；and the failure law of general significance is summarized. Through triaxial compression test，it is obtained that the strength of columnar jointed rock mass and cohesion of joint surface can reach high level under certain in-situ stress level，which agrees well with the results of field investigation. Meanwhile，the laws of load and deformation，occurrence of failure zone，distribution and development of fractured zone as well as energy dissipation are studied. Failure mechanism in many respects is discussed so as to better understand the mechanical properties.