太和铁矿西端帮冰碛土边坡稳定性分析方法研究

STUDY ON STABILITY ANALYSIS METHOD FOR MORAINE SOIL SLOPE IN WEST WALL OF TAIHE IRON MINE

针对太和铁矿西端帮冰碛土边坡这一具体工程,提出以冰碛土原位试验和室内试验成果为基础,耦合元胞自动机(CA)和FLAC3D进行冰碛土三轴数值模拟试验并建立其抗剪强度模型的方法;提出基于数值模拟,有效整合数值分析、极限平衡分析和可靠度分析方法的边坡稳定性综合分析方法。最后,以上述研究成果为基础,从多角度进行该冰碛土边坡的稳定性分析。位移矢量和变形分析表明,边坡的潜在破坏主要以浅表层剪切破坏为主,其均值安全系数较高(1.40～1.59),但因参数不确定性大,致使破坏概率亦较高(1.07%～3.36%),为不可接受的风险水平,故需采取适当的工程措施以降低风险。

Aiming at the moraine soil slope in west wall of Taihe Iron Mine, a method based on the results of in-situ test and laboratory test for moraine soil which couples automata（CA） with FLAC3D to conduct triaxial simulation test is presented and shear strength model for moraine soil is established. Firstly, CA is adopted to simulate the microstructure of moraine soil and specimens are prepared for triaxial simulation test. Secondly, the simulation procedures of specimens are introduced into FLAC^3D and then simulation tests are conducted. Finally, after the data from simulation results are processed, the probability models for shear strength are obtained. After that, a comprehensive analysis method of slope stability which integrates numerical analysis method, limit equilibrium method and reliability analysis method, is presented. In the comprehensive analysis method, three methods are linked to each other by adopting strength reduction technique, simplified first-order second-moment method and Rosenblueth method. The results of the three cases are interrelated consequently. According to the research results mentioned above, a multi-angle stability analysis of the moraine soil slope is made. The analyses of displacement vector and deformation indicate that the failure mode of the slope mainly exists as shallow circular shear failure. Although the mean factor of safety is high（1.40 - 1.59）, the probability of failure（1.07% - 3.36%） is high due to the higher uncertainty of shear strength parameters. As a result, the risk level of this slope is unacceptable so that some effective measures should be adopted.