甘肃天水地区黄土极限状态边坡的统计分析

在实际工程边坡设计中,往往参考临近自然边坡的坡率设计来进行人工开挖边坡。基于这种工程类比法,现场实测甘肃天水地区51个坡高40～150 m的黄土极限状态边坡断面,获得其坡高、坡宽及坡度参数,统计发现坡高与坡宽符合双对数线性关系,建立二者的相关方程;再将坡高按10m间距分段,每个坡高段取3个极限坡高,利用Morgenstern-Price法反演了不同坡高段的强度参数(内聚力和内摩擦角)。由反演结果发现,随着坡高的增大,黄土的综合内聚力增大,内摩擦角减小,此特点与黄土强度参数值随所处深度的变化规律基本一致。基于反演的强度参数和极限状态边坡坡高与坡宽的回归方程,进一步计算获得不同稳定系数下的坡高与坡宽的关系曲线，将该曲线制成图，可用来直接判定一个已知边坡的稳定系数，也可以用来确定拟设计边坡的坡度。

Statistical Analysis of the Limit State Loess Slope in Tianshui Area of Gansu

For the practical slope design, the angle of adjacent natural slope is often used as reference to design a cutting engineering slope, which is called as engineering analogical method. Based on the method, the profiles of 51 loess limit state slopes with the height of 40-150 m were surveyed in Tianshui area of Gansu, and the height, width and angle of the slopes were measured; the relationship between height and width of slope was double logarithmic linear, and the correlation equation was built; and then, the slope height was divided at intervals of 10 m, and three heights of limit state slopes for each interval were collected to calculate the strength parameters of cohesion and internal friction angle with Morgenstern-Price method. The inversion results showed that synthetically cohesion of loess increased, and internal friction angle decreased with the height of slope increasing, which was in accordance with the relationship between the strength parameters of loess and depth. Based on the inversive strength parameters and the regression equation of the height and width of limit state slope, the relationship curves between the height and width of slope were calculated with different stability coefficients, and the curves were drawn as a chart, which was used to determine the stability coefficient of a known slope and to confirm the angle of designed cutting slope.