基于动态演化规律及数值模拟方法的滑坡机理研究

Study on landslide mechanism based on dynamic evolution law and numerical simulation method

摘要

【目的】数值模拟方法广泛应用于滑坡灾变力学演化研究中，在滑坡治理过程中发挥着重要作用。为研究滑坡的触发机制，【方法】合理进行模型假设，准确设定边界条件及参数，建立二维动态数值模拟评估方法。以兰新铁路张家庄段滑坡为典型实例，通过GeoSlope、ABAQUS软件进行二维数值模拟，分析滑坡主剖面、滑动带塑性发展过程、滑动区域分布、位移分布、突变前后的增量位移等特征，结合二维极限平衡法以及试验分析滑坡机理。【结果】结果显示：承压水无法作用到滑动带顶部，在顶部滑动面上承压水作用引起的安全系数降低幅度比静水压力作用小；承压水对滑动带底部作用大，底部滑动面上承压水作用引起的安全系数降低幅度比静水压力作用大，安全系数直接降低了0.26。【结论】结果表明：施加承压水压力后，滑动带附近的Mises应力场发生显著变化，应力增量最高可达0.5 MPa,表明承压水作用显著改变了滑坡体内部的应力分布。此外，滑坡体在承压水作用下表现出明显的位移突变特征，坡顶水平位移在折减系数达到1.05时迅速增大，进一步证实了承压水作用对滑坡体稳定性的影响。通过数值模拟结合现场勘察和试验的综合方法和分析，合理地模拟了滑坡在地下水压力等复杂条件下的动态演化规律，对于边坡渐进破坏过程进行稳定性评价以及滑坡可视化动态演示提供了依据。

Abstract

[Objective] The numerical simulation method is widely used in the study of landslide disaster mechanical evolution and plays an important role in the process of landslide control. To study the triggering mechanism of landslide, [Methods]reasonable model assumptions are made, boundary conditions and parameters are set accurately, and a two-dimensional dynamic numerical simulation evaluation method is established. The landslide of Zhangjiazhuang section of Lanzhou-Xin Railway is taken as a typical example. GeoSlope and ABAQUS software are used to analyze the characteristics of landslide main section, slip zone plastic development process, slip region distribution, displacement distribution, and incremental displacement before and after abrupt change, and the landslide mechanism is analyzed by two-dimensional limit equilibrium method. [Results] The result show that the confined water cannot affect the top of the sliding zone, and the reduction of the safety factor caused by the action of confined water on the top sliding surface is smaller than that of the hydrostatic pressure, while the effect of confined water on the bottom of the sliding zone is larger. The reduction of the safety factor caused by the action of confined water on the bottom sliding surface is larger than that of the hydrostatic pressure, and the safety factor is directly reduced by 0.26. [Conclusion] Following the application of confined water pressure, substantial alterations were observed in the Mises stress field adjacent to the sliding zone, with stress increments reaching up to 0.5 MPa.These changes indicated that the action of confined water pressure significantly modified the stress distribution within the landslide mass.Additionally, distinct displacement discontinuities were exhibited by the landslide body under the influence of confined water pressure.Notably, horizontal displacements at the slope crest increased rapidly when the reduction factor reached 1.05.These findings further confirmed the substantial impact of confined water pressure on the stability of the landslide body. Through the comprehensive method and analysis of numerical simulation combined with field investigation and test, the dynamic evolution law of landslide under complex conditions such as groundwater pressure is reasonably simulated, which provides a basis for the stability evaluation of the progressive failure process of slope and the visual dynamic demonstration of landslide.

关键词

滑坡机理 / 地下水 / 水压力 / 动态演化 / 数值模拟 / 安全系数 / 地质灾害预警 / 降雨

Key words

landslide mechanism / ground water / water pressure / dynamic evolution / numerical simulation / safety factor / geological hazard warning / rainfall

基金资助

国家自然科学基金项目(42071264)

国家自然科学基金项目(41641027)

三峡后续工作地质灾害防治项目(0001212015CC60005)