多滑面边坡的可靠性分析

提出了结构可靠度计算的极值解法，对于功能函数为复杂的非线性形式的问题，该法可避免验算点法中因迭代初值的选择不当而使迭代过程不收敛或收敛于某个局部极小值而非最小值的缺点。把多滑面边坡看成一个串联系统，采用系统可靠性的上下界法对边坡的失稳进行可靠性分析。讨论了滑动面的粘聚力与摩控系数间的相关性对各滑动模式及整个结构体系的可靠指标及失效概率的影响，并指出在实际工程中应考察这种相关性，否则会引起较大误差。讨论了各滑动模式间的相关系数及滑动面个数对边坡系统失效概率的影响，指出了当各滑动模式间近似于完全独立或完全相关时或滑动面个数较小时，上下界法非常精确。

RELIABILITY ANALYSIS ON A SLOPE WITH SEVERAL SLIDE SURFACES

A limit value method is proposed to calculate the slope reliability with one slide surfaces, which can avoid the shortcomings of non-convergence or wrong convergence due to setting non-available initial values of POSM. The reliability of a slope with several slide surfaces is also analyzed by using narrow bounds method, and considering the slope as a series system. The correlation of cohesion and friction and will affect the reliability index and failure probability should be considered for practical engineering. When the correlation coefficient of each slide mode is zero or one, or when the number of slide surfaces is small, a very accuracte result can be obtained with the narrow bounds method.