基于双折减系数法与极限平衡法的顺层滑坡稳定性分析

Stability Analysis of Bedding Landslides Based on Double Reduction Coefficient Method and Limit Equilibrium Metho

以四川省布拖县龙潭乡冯家坪滑坡为例,利用FLAC3D软件设计了基于双折减系数法的滑坡稳定性分析程序,应用“GIS-Rhino-FLAC3D”耦合技术建立三维地质体模型。考虑黏聚力和内摩擦角在滑坡失稳过程中衰减速度和弱化程度的不同,以及非饱和土中基质吸力对土体抗剪强度的影响,提出一种以黏聚力和摩擦力的衰减权重定义综合安全系数的双折减系数法,并采用极限平衡法作对比计算,研究分析了顺层滑坡的稳定性。结果表明:设计的抗剪强度参数双折减程序可以得出安全系数云图,直观地反映滑坡安全系数的空间分布特征;与传统强度折减法相比,所提出的双折减系数法计算的滑动面分布范围和综合安全系数更精确,较极限平衡法误差更小,可以准确地反映滑坡的稳定状态。研究结果可为双折减系数法应用于滑坡灾害的防治提供参考。

Taking the Fengjiaping landslide in Longtan Township,Butuo County,Sichuan Province as an example,a landslide stability analysis program based on the double reduction coefficient method was designed using FLAC3D software.The coupling technique of GIS-Rhino-FLAC3D is applied to establish a 3D geological body model.Considering the different attenuation rates and degrees of cohesion and internal friction angle during landslide instability,as well as the influence of matric suction on soil shear strength in unsaturated soils,a double reduced coefficient method is proposed to define the comprehensive safety factor with the attenuation weights of cohesion force and friction force.The stability of bedding landslides was studied and analyzed using the limit equilibrium method for comparative calculations.The results are as follows.The designed shear strength parameter double reduction program can generate a safety factor cloud map,which intuitively reflects the spatial distribution characteristics of landslide safety factors.Compared with the traditional strength reduction method,the proposed double reduction coefficient method is more accurate in calculating the distribution range of sliding surface and comprehensive safety factor.Compared with the limit equilibrium method,the error is smaller and it can accurately reflect the stable state of landslide.The research results can provide reference for the application of the double reduction coefficient method in the prevention and control of landslide disasters.