基于FLAC的极限状态黄土高边坡强度参数反演

评价边坡稳定性关键问题是确定滑动面和可靠的抗剪强度参数。基于数值模拟技术,提出一种新的方法,可在无需事先假定滑动面的情况下得到可靠的强度参数。通过对兰州地区30个极限状态黄土边坡的坡高和坡宽参数进行统计,发现二者呈线性关系,且拟合度较高。根据所得到的回归方程,采用FLAC建立边坡模型,利用强度折减法对兰州地区边坡进行强度参数反演,将4个邻近高度边坡得到的参数反演曲线绘于同一坐标系中,得到该坡段综合强度参数值。反演结果表明:随着坡高的增加,黄土内摩擦角逐渐减小,黏聚力增大。根据计算结果,绘制60～120 m边坡高度下强度参数综合反演曲线,可直接进行黄土高边坡稳定性评价,提高了工作效率,也为高边坡几何形态的设计提供可靠的数据支持。

Strength Parameters Inversion of High Loess Slopeat Limit State Using FLAC

Determining sliding surface and reliable shear strength parameters are crucial issues in evaluating slope stability.A new method based on numerical simulation technology is proposed to obtain reliable strength parameters without presuming the sliding surface.The relationship between heights and widths of thirty loess slopes at limit state in Lanzhou region were found to be linear,and the fitting degree was high.According to the obtained regression equation,FLAC was applied to establish the slope model, and strength reduction method was used to inverse the strength parameters of slope at limit state.Furthermore, the parameter inversion curves of four adjacent high slopes were drawn in the unified coordinate system, and the comprehensive strength parameters of the segment were acquired.The inversion results show that with the increase of slope height,the cohesive force of loess increases gradually but internal friction angle decreases.According to the calculation results,the comprehensive inversion curves of strength parameters of slope with heights from 60 m to 120 m are drawn.The method could directly evaluate the stability of high loess slope,improve the working efficiency,and also provides reliable data to support the geometry design of high loess slope.