基于极限平衡的边坡稳定性严格计算方法
Rigorous Calculation Method for Slope Stability Based on Limit Equilibrium
目的 极限平衡法是边坡稳定性分析中最常用的计算方法。为了克服严格计算方法在安全系数求解的过程中面临的数值问题,改进计算方法,获得可靠的滑坡推力。 方法 在考虑条间力作用下(不假设条间力方向),将力的平衡方程整理成不平衡推力法的表达形式;根据相邻土条的几何关系,以及滑动土体两边最外侧土条(第1条块和第n条块)的水平法向力对土条底部滑面中点的力矩为零的条件,建立力矩递推关系式。分别推导出关于安全系数Fs和λ(比例系数)的两个表达式。在计算安全系数时,先通过初始值Fs=1、λ=0计算得到令人满意的Fs值,将得到的安全系数Fs代入方程求解对应λ值,再次迭代7~8次可得到公差小至0.000 1的Fs和λ。 结果 结果表明:该算法相比其他严格方法更简便,更易于收敛,且适用于任意形状滑裂面,可编写简单程序在计算机中实现,并可推广到工程界使用。
Purposes The limit equilibrium method is the most prevalent approach in slope stability analysis. For rigorous methods applicable to any sliding surface, numerical problems often arise in the process of safety factor solving. Methods Regarding the above points, the force balance equation was organized into the framework of unbalanced thrust method considering the influence of inter-bar forces without assuming their specific direction. By leveraging the geometric relationships between adjacent soil strips and the horizontal normal forces on the outermost soil strips (the first and nth strips) on both sides of the sliding mass, a moment recursion relationship was established with the condition that the moment at the midpoint of sliding surface at the base of soil strip was zero. Two separate expressions for the safety factor Fs and the proportionality factor λ were derived. In calculating the safety factor, an initial estimate was made by using Fs=1 and λ=0 to determine a satisfactory Fs。This safety factor was then substituted back into the equation to solve for the corresponding λ. This iterative process was repeated 7-8 times to achieve Fs and λ values with tolerances as small as 0.000 1. Results The results indicate that this algorithm is simpler, more straightforward, and converges more easily than other rigorous methods, making it applicable to sliding surfaces of any shape. Furthermore, it can be efficiently implemented on a computer through a simple program and has the potential for widespread applications in the engineering field.
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国家自然科学基金(52378360)
国家自然科学基金(51978438)
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