STABILITY ANALYSIS OF MULTI-STAGE HIGH SLOPE WITH LOESS UNDER RAINFALL INFILTRATION
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摘要: 在西北地区进行基础工程建设,遇到了大量的多级黄土高边坡工程。边坡工程属于永久性工程,难免遇到降雨状况。降雨入渗会引起边坡土体饱和度与土体重度的变化,进而导致边坡体基质吸力与有效应力场的变化,使边坡的稳定性受到较大的影响。本文通过考虑边坡体不同深度处基质吸力随雨水入渗的变化情况,建立了渗流场与应力场的耦合计算模型,对降雨入渗条件下多级黄土高边坡的稳定性进行分析。最后,依托实际边坡工程,利用PLAXIS 3D岩土有限元软件,建立边坡稳定性计算模型,通过设置降雨量随时间的变化函数与渗流边界条件,进行降雨入渗条件下多级黄土高边坡的稳定性数值计算,并与理论分析结果进行了对比分析。根据数值计算结果可得到多级黄土高边坡在降雨入渗条件下的变形、基质吸力、有效应力、潜在滑移面以及安全系数的变化情况,从而对降雨入渗影响下多级黄土高边坡的稳定性做出分析。研究结果可为降雨入渗条件下多级黄土高边坡的稳定性的研究提供一定的指导作用。Abstract: In the northwest, a lot of multi-stage high slopes with loess have been encountered in the construction of basic engineering. Slope engineering belongs to permanent project. So it is unavoidable to meet the conditions of rainfall. Under rainfall infiltration, the degree of saturation and mass of soil slope increase, which can further cause the change of slope matric suction and effective stress. As a result, the stability of the slope can be greatly influenced. In this paper, the coupling calculation model of seepage field and stress field is established. It considers the changes of the matrix suction as the rain water infiltration at the different depths of the slope body. Then, the stability of the multi-stage high slope with loess under the condition of rainfall infiltration can be analyzed. Then, according to an actual engineering and using the PLAXIS 3D geotechnical finite element software, the calculation model of slope stability is established. By setting the variation function of rainfall with the time and boundary condition, the stability calculation of multi-stage high slope with loess is carried out under the condition of rainfall infiltration. And then, The numerical calculation results are compared with the theoretical calculation results. According to the numerical calculation results, the changes of the deformation, matrix suction, effective stress, potential slip surface and safety factor of the multi-stage high slope with loess under the condition of rainfall infiltration are obtained. And the stability of the multi-stage high slope with loess under the condition of rainfall infiltration are analyzed. The study results can provide some guidance for the design of the multi-stage high slope with loess under the rainfall infiltration.
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表 1 土体物理力学参数
Table 1. Physico-mechanical parameters of soil mass
土层 重度γ /kN·m-3 总弹性模量E /MPa 泊松比μ 黏聚力c /kPa 内摩擦角φ /(°) 界面黏结强度/kPa 黄土 17.0 10 0.44 12 25 60 -
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