【摘要】 本文针对硅质岩路堑边坡,先通过野外调查测量,得到结构面的概率模型,然后进行室内吸水性试验、单轴压缩变形试验、抗拉强度试验及直接剪切试验得到硅质岩的物理力学参数,为数值模拟提供依据;最后通过有限元强度折减法,对基于Monte Carlo随机模拟的方法生成的模型进行计算。试验结果表明,硅质岩十分致密,强度大,单轴压缩时,在应力为峰值应力的50%~65%时,岩体进入裂缝急剧扩展阶段,此时的应力—应变曲线出现"平台"。但"平台"过后应力还能继续增长,直至劈裂破坏。以硅质岩为代表的有软弱结构面的硬质岩边坡在天然条件下一般处于稳定状态,此时软弱夹层因受压紧密不易发生滑动,而在开挖揭露软弱夹层后,坡体才产生顺结构面的下滑现象。模拟结果表明,在原始坡形及开挖二级边坡时,坡体的稳定性较好,发生破坏的概率较小,而在开挖到一级边坡时,发生失稳的概率为76%。坡体的破坏模式为开挖导致的应力重分布使坡脚处先产生应力集中,岩体内的微破裂逐渐累积,变形主要沿着结构面及结构面上的岩体向坡体后缘扩展直至贯通,形成滑移—拉裂式破坏。50次计算结果的叠加表明,潜在滑面发生在与开挖面垂直距离7~9 m的概率为46%,最深的位置在11.3 m,这一结果可为坡体的支护设计提供依据。更多还原

【Abstract】 Aiming at silicolite cutting slope,distribution model of discontinuities is established through the network modeling by field investigation firstly. Then thewater absorption,uniaxial compression tests,uniaxial tensile tests,direct shear tests are doneto get parameters for numerical simulations. Finally calculate the model generated by Monte Carlo random simulation through the finite element shear strength reduction method. And the tests results indicate that the silicastone is hard and compact. In uniaxial compression tests,when the compressive stress at the 50% ~ 65% of the peak stress,rock enters the crack sharply extension stage,and the stress-strain curves appears a "platform". But after the "platform",the stress still increase until splitting failure. The hard rock slope represented by silicastone slope with weak structural surface are stable in natural condition and the discontinuity surfaces are compressed tightly to slide down hardly. However,as the slope cutting reveal the discontinuity surface,the slope slides along the discontinuity surface. And the simulatedresults indicate that the slope is stable in the original and secondary cutting slope,however,the slope failue probability during the final cutting slope cutting is 76%. The failure mode is sliding-tension type,as the excavating leads to stress concentration at the slope toe and the micro-fracture accumulate little by little,the deformation extend to the trailing edge of slope along the structural surface. The 50 times resultssuperposition shows that the deepest potential sliding surface lies in the 11. 3 m and the 7 ~ 9 mdepth probability is 46%,and the results may provide basis for the supporting design.更多还原