強(qiáng)降雨作用下黃土-泥巖接觸面滑坡模型試驗(yàn)及穩(wěn)定性研究

摘要： 為探究黃土-泥巖接觸面滑坡在強(qiáng)降雨作用下的破壞特征并對(duì)其進(jìn)行穩(wěn)定性評(píng)價(jià)，以甘肅省隴南市徽縣某滑坡為依托，采用物理模型試驗(yàn)、有限元數(shù)值模擬及理論分析的手段，揭示黃土-泥巖接觸面滑坡的變形破壞特征，并改進(jìn)理論分析計(jì)算方法。研究表明：（1）在持續(xù)性強(qiáng)降雨作用下，黃土與泥巖交界面附近土體一直處于飽和狀態(tài)，黃土-泥巖接觸面滑坡的主要變形過程為滑移拉裂，坡體的破壞模式為牽引-推移復(fù)合式;（2）滑坡穩(wěn)定性隨著降雨強(qiáng)度的增加逐漸降低，通過多組滑坡模型試驗(yàn)，得到不同降雨強(qiáng)度下滑坡啟動(dòng)時(shí)間，發(fā)現(xiàn)降雨強(qiáng)度與滑坡啟動(dòng)時(shí)間呈對(duì)數(shù)關(guān)系;（3）通過模擬滑坡位移變化，發(fā)現(xiàn)黃土-泥巖接觸面處孔隙水壓力最高并向周圍不斷擴(kuò)散降低，符合黃土-泥巖接觸面滑坡實(shí)際入滲特征，驗(yàn)證了滑坡模型試驗(yàn)所得結(jié)論的準(zhǔn)確性;（4）基于傳統(tǒng)的不平衡推力法，考慮降雨入滲所產(chǎn)生滲透力的影響，改進(jìn)穩(wěn)定性計(jì)算方法，并對(duì)滑坡穩(wěn)定性進(jìn)行評(píng)估，結(jié)果顯示滑坡穩(wěn)定性系數(shù)明顯低于規(guī)范所求，表明坡體從降雨開始至發(fā)生失穩(wěn)所需時(shí)間明顯小于常規(guī)預(yù)測(cè)值。研究結(jié)論可以為滑坡災(zāi)害的研究與防治提供重要依據(jù)。

關(guān)鍵詞： 黃土-泥巖接觸面滑坡; 降雨入滲; 模型試驗(yàn); 數(shù)值模擬; 穩(wěn)定性分析

中圖分類號(hào)： P642.22""""" 文獻(xiàn)標(biāo)志碼：A"" 文章編號(hào)： 1000-0844（2025）02-0361-10

DOI：10.20000/j.1000-0844.20231121005

Model tests and stability analysis of loess-mudstoneinterface landslides under heavy rainfall

WANG Haiming1， ZHU Dianzhi1， DING Yutao1， YANG Xiaohui2， ZHAO Zhizhong2

（1. Gansu Electric Power Design Institute Co.， Ltd.， China Energy Construction Group， Lanzhou 730050， Gansu， China;

2. School of Civil Engineering， Lanzhou University of Technology， Lanzhou 730050， Gansu， China）

Abstract：

In this study， the failure characteristics of loess-mudstone interface landslides under heavy rainfall were investigated， and their stability was evaluated. In particular， physical model tests， finite element numerical simulation， and theoretical analysis were conducted to reveal the deformation and failure characteristics of loess-mudstone interface landslides and improve the theoretical analysis and calculation methods， taking a landslide incident that occurred in Hui County， Longnan City， Gansu Province， as a case study. Several results were obtained. （1） Under the action of continuous heavy rainfall， the soil near the loess-mudstone interface is always in a saturated state. The main deformation process of loess-mudstone interface landslide is sliding-crack， with a composite failure mode of traction-push. （2） Landslide stability gradually decreases with the increase in rainfall intensity. After conducting multiple sets of landslide model tests to determine the landslide initiation times under different rainfall intensities， the results reveal that rainfall intensity and the landslide initiation time are logarithmically related. （3） Upon simulating the displacement changes of loess-mudstone interface landslide， it is revealed that the pore water pressure at the interface between loess and mudstone is the highest and gradually diffuses and decreases. This result is consistent with the actual infiltration characteristics of loess-mudstone interface landslides， thus verifying the accuracy of the conclusions obtained from the landslide model test. （4） Based on the traditional unbalanced thrust force method， the stability calculation method is improved， and the landslide stability is evaluated considering the influence of the seepage force generated by rainfall infiltration. The results indicate that the landslide stability coefficient is significantly lower than that required by the code， indicating that the time from the beginning of rainfall to slope instability is shorter than the conventional prediction value. The research conclusions provide an important basis for the research and prevention of landslide disasters.

Keywords：

loess-mudstone interface landslide; rainfall infiltration; model test; numerical simulation; stability calculation

0 引言

黃土-泥巖接觸面滑坡作為黃土地區(qū)主要的突發(fā)性地質(zhì)災(zāi)害之一，威脅著人們的生命財(cái)產(chǎn)安全，制約了當(dāng)?shù)氐纳鐣?huì)經(jīng)濟(jì)發(fā)展。……