摘要
基于滑移线场理论,按边坡坡面变形量评价其稳定性,提出均质边坡极限曲线法。该法是求有重边坡极限荷载的逆过程,也是强度折减法的对偶过程。以特征线法差分方程组(SCM)和试验方程近似公式(CCM)求得的极限坡面曲线与坡面线相交为变形破坏准则,定义了安全度(DOS)和破坏度(DOF)2个评价指标。该方法不必假设和搜索临界滑动面。经典考题和典型算例的验算表明,随着节点的增加SCM法计算精度增加,边界步长不变时,3次样条插值求得的变形破坏准则判断值不变,说明SCM算法稳定。典型算例的计算数据和图例表明,边坡角变大时边坡稳定性降低,极限坡面曲线与坡面由无交点变为有交点,证明了变形破坏准则的正确性。由2个例题计算结果对比可知,安全系数较大时,SCM法、CCM法计算结果与其具有可比性,相对于原边界条件增加了外荷载;安全系数变小时,SCM法、CCM法偏于保守。34个样本计算正确率为安全系数法67.7%,应力状态法73.5%,CCM法79.4%,SCM法70.6%,表明SCM法和CCM法正确率较高,计算结果可靠,SCM法、CCM法因素敏感性分析结论与安全系数法完全一致。在露天矿边坡稳定性和最终边坡角的分析与计算中,SCM法、CCM法结论与原报告相同,当参数变小时CCM法更有利于实践,具有一定的工程应用价值。
Based on the theory of slip line field, this paper proposes a limit curve method of slope stability according to the deformation situation; the method is the inverse process for computing a heavy slope ultimate load and the dual process of strength reduction method. Defines two evaluation indexes: the degree of safety(DOS) and the degree of failure(DOF) according to the deformation failure criterion of the limit stable slope curve and the slope surface intersection computed by characteristic line difference method(SCM) and the slope limit experimental approximate formula(CCM). The method does not require assuming and searching critical slip surface. Classic examples and typical examples show that with the increase of nodes, the accuracy of SCM increases; when boundary step is constant, the judgment value obtained by three spline interpolation are unchanged, which proves the stability of SCM. Typical examples show that the larger the slope angle becomes, the lower the slope stability is; limit slope curve and slope is from without intersection to intersection, which proves that the correctness of the deformation failure criterion. Comparing the results from the two examples show that the safety factor is large and SCM, CCM results are comparable; this paper increases external load relative to the original boundary conditions; so the safety factor becomes smaller; SCM, CCM is conservative. To calculate the correct rate, this paper uses 34 samples: safety factor method is 67.7%, the stress state method is 73.5%, CCM is 79.4% and SCM is 70.6%, which indicates that SCM, CCM correct rate is higher. The conclusions of SCM, CCM factor sensitivity analysis and safety coefficient method are completely consistent. By analyzing and computing the slope stability and the ultimate slope angle of open pit mining, the report about SCM, CCM is the same as the original; when the parameter variable is smaller, CCM is more conducive to practice, which indicates that the method has a certain value in engineering applications.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2014年第S1期156-164,共9页
Rock and Soil Mechanics
关键词
极限曲线法
变形破坏准则
安全度
破坏度
limit curve method
deformation failure criterion
degree of safety
degree of failure