上软下硬地层边坡地震动载下稳定特性的拟静力分析方法

结合强度折减法思想,并考虑到上软下硬地层边坡特点,基于拟静力法,对地震作用下的上软下硬地层边坡稳定性进行分析。采用正交试验和极差分析法,比较坡高H、坡角β、上部地层厚度h和软硬地层参数对不同强度地震下的上软下硬地层边坡稳定性的影响。当H、β、h一定,而上部地层内摩擦角s、黏结力cs及水平地震作用系数kH在一定范围内取值时,研究这3个参数变化对上软下硬地层边坡稳定性的影响,并分析了上软下硬地层边坡的稳定性演化规律和破坏过程。在H、β、h以及软硬地层参数一定时,分析kH和比例系数ξ的取值对上软下硬地层边坡稳定性的影响。研究结果表明:β和h是影响地震作用下的上软下硬地层边坡稳定性的主要因素,其次是H;而且h的敏感度会随着地震强度的增强,进一步增大。在不同H、β和地震强度下,边坡安全系数F_s与c_s和Φ_s近似成线性比例关系。水平地震作用对安全系数影响最大,竖向地震作用次之。

Method Applied to Pseudo-Static Analysis on Slope Stability Features of Soft Top and Hard Bottom Stratum under Seismic Dynamic Load

In combination with an idea of the strength reduction method,in consideration of the slope features of the soft top and hard bottom stratum,based on the pseudo-static method,an analysis was conducted on the slope stability of the soft top and hard bottom stratum under the role of the seismic. An orthogonal test and extremum difference analysis method were applied to compare the slope height H ,slope angle β,thicknes sh of top stratum and parameters of the soft and hard stratum affected to the slope stability of the soft top and hard bottom stratum under the different intensity seismic.When the H ,β and h were certain,when an value selection was conducted on the internal friction angle?s and co-hesion c s of the top stratum as well as the horizontal seismic role coefficient kH ,the paper studied the three parameter variations affected to the slope stability of the soft top and hard bottom stratum and analyzed the slope stability evolution law and failure process of the soft top and hard bottom stratum. When the H ,βand h as well as the parameters of the soft and hard stratum were certain,the paper an-alyzed the value selection on the kH and proportional coefficientξ affected to the slope stability of the soft top and hard bottom stratum.The study results showed that theβ and h would be major factors affected to the slope stability of the soft top and hard bottom stratum under the seismic role and the H would be the second factor.The sensitivity of the h would be further increased with the seismic inten-sity enhanced.Under the different H ,β and seismic intensity,the slope safety coefficient F s and c s as well as ?s would approximately be in a linear proportional relationship.The horizontal seismic role would have max influences to the safety coefficient and the vertical seismic role would be the second.