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针对预应力锚杆复合土钉支护结构的稳定可靠性分析问题,以极限平衡理论为基础,建立了基坑稳定性分析安全系数求解公式和可靠性分析功能函数。以土体力学参数为作为随机变量,应用Monte Carlo重要抽样法计算了基坑稳定性可靠度指标和失效概率,通过工程实例进行了分析。分析表明:该稳定性计算公式计算的安全系数符合工程要求并且通过可靠性分析,因而使用该方法对复合土钉支护结构稳定性计算是有效的;基坑可靠性分析中,可靠度指标?和失效概率Pf受土体黏聚力、内摩擦角与摩阻力的变异系数的影响较大,前者随变异系数的增大而减小,后者随变异系数的增大而增大;对于土体力学参数分布选型参数c采用对数分布,φ、qsik采用正态分布对可靠度计算分析比较合理。
Aiming at the problem of stability and reliability analysis of prestressed anchor composite soil nailing structure, based on the theory of limit equilibrium, the safety factor solving formula and reliability analysis function of foundation pit stability analysis are established. Based on the soil mechanics parameters as random variables, Monte Carlo method is used to calculate the reliability index and failure probability of foundation pit stability. The engineering example is used to analyze the reliability of the foundation pit. The analysis shows that the safety factor calculated by the stability calculation formula meets the engineering requirements and passes the reliability analysis. Therefore, the method is effective for the stability calculation of composite soil nailing support structure. In the reliability analysis of foundation pit, And failure probability Pf are greatly affected by the coefficient of variation of cohesion, internal friction angle and friction resistance. The former decreases with the increase of the coefficient of variation and the latter increases with the increase of the coefficient of variation. Physical parameters of the selection parameters c using the logarithmic distribution, φ, qsik using the normal distribution of the reliability calculation and analysis is more reasonable.