ISSN 1000-3665 CN 11-2202/P
    纪佑军,熊军,蒋国斌,等. 考虑应变软化的鸡场镇降雨型滑坡数值分析[J]. 水文地质工程地质,2024,51(4): 178-188. DOI: 10.16030/j.cnki.issn.1000-3665.202303036
    引用本文: 纪佑军,熊军,蒋国斌,等. 考虑应变软化的鸡场镇降雨型滑坡数值分析[J]. 水文地质工程地质,2024,51(4): 178-188. DOI: 10.16030/j.cnki.issn.1000-3665.202303036
    JI Youjun, XIONG Jun, JIANG Guobin, et al. Numerical analysis of rainfall type landslide in Jichang town considering strain-softening[J]. Hydrogeology & Engineering Geology, 2024, 51(4): 178-188. DOI: 10.16030/j.cnki.issn.1000-3665.202303036
    Citation: JI Youjun, XIONG Jun, JIANG Guobin, et al. Numerical analysis of rainfall type landslide in Jichang town considering strain-softening[J]. Hydrogeology & Engineering Geology, 2024, 51(4): 178-188. DOI: 10.16030/j.cnki.issn.1000-3665.202303036

    考虑应变软化的鸡场镇降雨型滑坡数值分析

    Numerical analysis of rainfall type landslide in Jichang town considering strain-softening

    • 摘要: 降雨入渗改变斜坡渗流场的同时也降低了土体强度,极易诱发滑坡。滑坡过程中,滑带土体常呈现应变软化现象。以应变软化模型为基础的双参数强度折减法的研究,目前处于起步阶段,以往研究及分析滑坡稳定性时均忽略了渗流场的影响。六盘水地区红棕色土保水性强,有明显的应变软化特征,该地曾发生多次大中型滑坡。根据红棕色土特点研究致灾机理,有利于滑坡的防治。针对六盘水鸡场镇周家坡滑坡建立三维地质模型,基于非饱和土流固耦合理论建立了坡体流场与应力场相互作用的数学模型,利用有限元和考虑土体应变软化的双参数强度折减法,对滑坡进行雨水渗流和稳定性模拟。结果表明:在降雨后雨水多在表层土中沿坡面切向和横向流入下缘和冲沟,并非全部垂直入渗。相对上缘其他区域,冲沟底部饱和度上升明显,强度下降最大。随降雨时间的延长,坡体内形成沿冲沟的塑性贯通区,使得滑坡稳定性大幅下降。降雨过程中对比经典折减法和考虑应变软化的双折减法所得稳定系数由偏小转为偏大,但差距均在4%以内。由此可见,红棕色土应变软化对滑坡稳定性负面影响不显著,且随降雨而减弱,建议对此类滑坡的防治重点在降低冲沟土体渗透性。研究结果可为同类滑坡的防治提供一定的理论依据。

       

      Abstract: Rainfall infiltration not only changes the seepage field of the slope, but also reduces the soil strength, which is easy to induce landslide. The soil in the slip zone often shows strain softening during the landslide process. However, the research of the two-parameter strength reduction method based on the strain softening model is still in its infancy, and the influence of seepage field has been ignored when analyzing the stability of landslides in the previous studies. The red-brown soil in the Liupanshui area has strong water retention and obvious strain softening characteristics, and many large and medium-sized landslides have occurred in this area. Understanding the disaster-causing mechanism according to the characteristics of red-brown soil is conducive to the prevention and control of landslides. A three-dimensional geological model was established for the Zhoujiapo landslide in Jichang town, Liupanshui city. Based on the fluid-structure interaction theory of unsaturated soil, a mathematical model of the interaction between the flow field and the stress field of slope was established. The rainwater seepage and the stability of the landslide were simulated by using the finite element and the two-parameter strength reduction method considering the strain softening of the soil. The results show that after rainfall, the rainwater mostly flows into the lower edge and gully along the slope in the surface soil in the tangential and transverse directions rather than all vertical infiltration. The saturation at the bottom of the gully increases significantly and the intensity decreases the most compared to other areas at the upper edge. With time extension of rainfall, a plastic penetration zone along the gully is formed in the slope, which greatly reduces the stability of the landslide. Compared with the classical reduction method, the stability coefficient obtained by the double reduction method considering strain softening in the rainfall process changes from small to large, but the difference was within 4%. It can be seen that the negative impact of red-brown soil strain softening on landslide stability is not significant and weakens with rainfall. The prevention and control of such landslides should focus on reducing the permeability of gully soil. This study provides a theoretical basis for the prevention and control of similar landslides.

       

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