西域砾岩高边坡坡脚侵蚀的破坏机理研究

西域砾岩中常常夹杂泥岩交互层,泥岩遇水软化易造成边坡失稳破坏。以分析西域砾岩高边坡破坏机制为目标,利用FLAC3D软件对西域砾岩高边坡坡脚软岩软化的破坏机理进行数值模拟试验研究,运用正交试验设计原理,制定9组试验方案,采用极差分析法分别对坡度、坡高、凝聚力、内摩擦角四个因素的敏感性做分析计算。结果表明:西域砾岩高边坡坡脚软岩软化造成的破坏由边坡潜在破裂面上部受拉破坏区和下部剪切破坏区共同组成,形成与坡脚呈45°的折线状滑裂面。4个因素中,凝聚力的变化使边坡的稳定性受软岩软化的影响最为显著,坡度和内摩擦角的变化产生的影响次之,且两者处于同一水平,而坡高变化产生的影响相对较弱。

Study on failure mechanism of toe erosion of high Xiyu conglomerate slope

As Xiyu conglomerate is often mixed up with mudstone alternating layers，the instability failure of the slope is prone to be caused when the mudstone is softened by water. An experimental study of numerical simulation on the mechanism of the softened failure of the toe of high conglomerate slope is made herein with FLAC3D by taking the failure mechanism as the objective; in which the sensitivities of the factors of the slope degree，height，cohesion and angle of internal friction of the slope are respectively analyzed and calculated with extreme difference analysis method through nine sets of experiment schemes in accordance with the orthogonal experiment design principle. The result shows that the failure of the toe of high conglomerate slope commonly consists of the upper tensile failure zone and the lower shear failure zone of the potential failure plane，which forms a broken line sliding plane with the angle of 45° to the toe. Among the four factors mentioned above，the impact from the softening of soft rock on the stability of the slope due to the variation of the cohesion is significant and the impacts from the both the slope degree and the angle of internal friction are secondary，while both of them are on a same level. However，the impact from the slope height is relatively weak.