滑坡堆积体滑带土强度参数反算研究

根据滑坡堆积体的特点,提出一种新的反算滑坡堆积体滑带土强度参数的方法—差分进化支持向量机方法.该方法在滑面位置已经查明的情况下,建立堆积体稳定性计算模型,根据堆积体变形情况确定计算剖面的稳定性评价指标.利用均匀设计方法,构造2因素25水平的计算方案,采用极限平衡分析计算出各剖面在不同c、φ值下的安全系数,将其作为学习样本.通过支持向量机学习,建立参数与安全系数之间的非线性映射关系,基于这种关系,利用差分进化算法搜索滑带土强度参数.以溪洛渡水电站左岸谷肩堆积体为例,采用基于极限平衡法的差分进化支持向量机方法反算滑带土强度参数,利用反算出的强度参数,对堆积体的稳定性进行分析.研究表明,计算出的安全系数与稳定性评价指标误差较小,说明该方法效果良好,适用于反算滑坡堆积体滑带土强度参数,对工程具有指导意义.

Back-analysis of Strength Parameters of Slip Soil of Landslide Accumulation

According to the characteristics of the landslide accumulation, a new method to back-calculate the soil strength parameters of landslide using differential evolution support vector machine was proposed. In the case that slip surfaces have been identified; the stability calculation model of accumulation body was built. The safety factor of the calculated profile was determined with different combinations of deformation and stability evaluation index of accumulation body. Two factors and twenty five levels of calculation programs were constructed according to the uniform design method. Minimum factors of safety were determined with different combinations of c and ~ using limited equilibrium analysis. The nonlinear relationship between c, q~ and minimum factors of safety were established using support vector machine. The soil strength parameters of landslide were recognized based on this relationship. Taking the left bank valley accumulation body of Xiluodu hydropower station for example, differential evolution support vector machine based on the limited equilibrium analysis was used to back-calculate the strength parameters. The stability of the accumulated body was analyzed by the strength parameters. The results show that the deviation between calculated safety factor and given safety factor is very small. This method is well applicable to back-calculate the soil strength parameters of landslide accumulation and has important guiding significance.