土岩混合边坡侧向岩土压力分布规律研究

Study on the Lateral Soil and Rock Pressure Distribution of Mixed Soil-Rock Slopes

摘要: 本文将以红黏土–灰岩土岩混合边坡为对象，充分考虑土层和岩层之间可能存在的相互作用，通过改变土岩分界面形态、土岩比、外倾结构面，利用Flac3d有限差分软件，对具有不同地层结构的红黏土–灰岩土岩混合边坡的岩土压力分布规律进行系统的研究。主要成果如下：在红黏土–灰岩土岩混合边坡中，支护结构所承受的岩土压力随着土层厚度比例增大，桩后侧向压力总值显著增大，整体上表现出“R”形分布特征，土压力在土岩界面处发生回收现象，这种回收现象随着土层厚度的增加而变得更加明显；土岩分界面顺倾时，随着土岩分界面坡率的增大，上部土层土压力整体表现为先降低再增加再降低的趋势，且随着土岩分界面坡率增加至0.2，上部土层土压力由“C”形分布逐渐变为近似梯形的分布形式；当岩层存在外倾结构面时，岩层自身稳定性降低，桩后岩土体之间的错动变形减弱，岩层对土体的限制作用减弱，从而弱化了界面处的土压力回缩现象，土层土压力整体趋势演变为三角形分布。

Abstract: This article focuses on red clay-limestone mixed soil-rock slopes, fully considering the possible interaction between soil layers and rock layers. By changing the shape of the soil-rock interface, the soil-rock ratio, and the outward-inclined structural plane, and using Flac3d finite difference software, the study systematically examines the stress distribution patterns of red clay-limestone mixed soil-rock slopes with different geological structures. The main findings are as follows: In red clay-limestone mixed soil-rock slopes, the geotechnical pressure on the support structures increases significantly as the proportion of soil thickness grows, and the total lateral pressure behind the piles shows an overall “R”-shaped distribution. Soil pressure is recovered at the soil-rock interface, and this recovery becomes more noticeable as the soil layer thickens. When the soil-rock interface is inclined in the direction of the slope, as the slope rate of the soil-rock interface increases, the upper soil layer initially decreases, then increases, and finally decreases in pressure. When the slope rate reaches 0.2, the upper soil layer pressure distribution changes from a “C” shape to an approximately trapezoidal form. When there is an outward-inclined structural plane in the rock layer, the stability of the rock layer decreases, the relative displacement deformation between the rock and soil behind the pile diminishes, and the rock’s restriction on the soil weakens, thereby reducing the soil pressure recovery at the interface. Overall, the soil pressure in the soil layer evolves into a triangular distribution trend.