STUDY OF FAILURE BEHAVIOR OF DEEP HARD ROCK UNDER POLYAXIAL STRESS CONDITIONS
PAN Pengzhi，FENG Xiating，QIU Shili，ZHOU Hui
(State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China)
摘要针对深埋硬岩在多轴应力条件下的破坏特征，在笔者所在课题组工作的基础上，提出能够反映岩石在多轴应力作用下力学参数随塑性内变量的演化关系以及中间主应力和最小主应力对深埋硬岩脆延转换行为影响的岩体局部劣化模型(rock mass local deterioration model，RLDM)，该模型考虑真实岩体应力状态对岩体力学行为的控制作用，并嵌入到自行开发的三维弹塑性细胞自动机软件系统中，而基于局部作用原理的细胞自动机方法能够方便地考虑岩石破坏过程中局部力学参数的动态更新。实验室尺度岩样的破坏过程模拟，较好地反映了随着围压的升高，岩石由脆性向延性转化的试验现象；工程尺度的锦屏二级水电站引水隧洞破坏行为模拟，获得的隧洞破裂模式较好地反映现场实际破坏现象，从而验证模型和模拟方法的正确性和合理性。在此基础上，以深埋硬岩为研究对象，分别考虑不同侧压力系数、不同中间主应力大小和方向，分析多轴应力对深埋硬岩破裂行为的影响，解释造成深埋硬岩隧洞复杂破裂模式的原因。结果表明，最小主应力升高使深埋隧洞的稳定性增强；深埋隧洞围岩的稳定性具有中间主应力效应及其区间性的特征。
Abstract：Based on the failure behavior of deep hard rock and group works，a rock mass local deterioration model(RLDM) is developed to reflect the evolution of deformation and strength parameters of rocks with plastic variables under polyaxial stress conditions. The model is integrated into a self-developed three dimensional elastoplastic cellular automaton(EPCA). The cellular automaton technique，which is based on the localization theory，is convenient to perform the dynamic updating of local mechanical parameters. The EPCA code with RLDM is used to study the influence of polyaxial stress on failure behavior of rock specimens in laboratory and in-situ deep diversion tunnel of Jinping II hydropower station. The modeled complete stress-strain curves of rocks under triaxial compression can well reflect the transition from brittle failure to ductile failure of rocks；the curves are agreement with experimental phenomenon. The modeled failure mode of Jinping II diversion tunnel well reflects the actual failure mechanism. Based on the calibrations of the model and numerical method，it is used to simulate the failure behaviors of deep hard rock tunnels by considering different lateral stress coefficients and different intermediate principal stresses and their directions. Influence of polyaxial stress on fracture of deep hard rock is analyzed；and causes of complex failure modes of deep hard rock tunnels are also explained. It is concluded that，the increase of minor principal stress increases the stability of the tunnel. The stability of deep tunnel shows the phenomenon of intermediate principal stress effect and interval characteristics.
潘鹏志，冯夏庭，邱士利，周 辉. 多轴应力对深埋硬岩破裂行为的影响研究[J]. 岩石力学与工程学报, 2011, 30(6): 1116-1125.
PAN Pengzhi，FENG Xiating，QIU Shili，ZHOU Hui. STUDY OF FAILURE BEHAVIOR OF DEEP HARD ROCK UNDER POLYAXIAL STRESS CONDITIONS. , 2011, 30(6): 1116-1125.
HAIMSON B，RUDNICKI J W. The effect of the intermediate principal stress on fault formation and fault angle in siltstone[J]. Journal of Structural Geology，2010，32(11)：1 701-1 711.
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2011, Vol. 30 
