岩质边坡稳定坡角影响因素及其确定方法

Rock slope stability influence factors of slope angle

  • 摘要: 目前研究岩质高边坡稳定性的方法很多,但研究边坡开挖后稳定性及边坡坡角与结构面倾角的关系却较少,且多运用数值分析方法确定岩质高边坡的稳定性,很少用解析解的方法。基于块体的极限平衡理论,岩质高边坡发生整体破坏,其滑移面为顺层直面,推导出岩质高边坡受结构面控制的最小安全系数解析解。分析解析表达式中各个参数对确定影响边坡稳定性的敏感性因素,表明受结构面影响的岩质高边坡安全系数与岩体的黏聚力、内摩擦角成线性正比关系,与岩体重度、边坡高度和边坡坡角成反比,随着结构面倾角的增加而呈先减后增的趋势,据此得出在既定的安全系数下岩质高边坡稳定坡角的解析解,分析得出受结构面控制的岩质边坡稳定坡角与黏聚力、内摩擦角、边坡坡高和安全系数等的关系曲线。通过对已有工程实例的计算分析,比较理论公式和数值模拟计算结果的差异,证明理论公式可以应用于实际工程之中。

     

    Abstract: At present, there are many ways for studies on the stability of high rock slope, but the studies of rock excavation slope stability as well as relationships between the slope angle and the inclination of structural plane are rarely reported. Lots of numerical analysis methods have been used to determine the stability of high rock slope, and few people use the method of analytical solutions in analysing the secondary terrace stability of the high rock slope. Based on the block limit equilibrium theory, assuming that the secondary terrace of the high rock slope is totally damaged, and that the slip plane is a straight surface, the analytical solutions of the minimum safety factor of the secondary terrace the high rock slope are derived. Analysis of various parameters in the analytic expressions to determine the sensitivity of factors influencing the stability of the slope shows that the stability coefficient of the secondary terrace of the high rock slope is linearly proportional to rock cohesion and internal friction angle, and inversely proportional to the slope height and slope angle, with the increase of the large slope angle of the first terrace. According to the analytic expressions, using the safety factor of the slope stability and the established secondary terrace analytical solutions of the high rock slopes stable slope angle, the secondary terrace stable slope angle and cohesive force, internal friction angle, slope height and safety coefficient curves are obtained. Through calculation and analysis of existing engineering examples, comparing the differences between the theoretical formula and the numerical simulation results, it is shown that the theoretical formula, which has guiding significance for the design of the rock slope and landslide treatment, can be applied to practical engineering.

     

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