工程科学与技术2026，Vol.58Issue(2)：109-122,14.DOI:10.12454/j.jsuese.202400550
降雨及库水联合作用下膨胀土滑坡变形机理研究
Study on the Mechanism of Landslide Promotion of Expansive Soil Under the Combined Action of Rainfall and Reservoir Water
摘要
Abstract
Objective The widespread occurrence of expansive soil landslides poses a significant threat to the long-term stability and safe operation of the Danjiangkou Reservoir.Expansive soil is rich in hydrophilic minerals such as montmorillonite and illite,which are highly sensitive to water.The structural characteristics,expansion and contraction behavior,and strength attenuation properties of expansive soil constitute the main factors leading to the instability and failure of expansive soil landslides and exhibit typical features of shallow depth,traction movement,gentle slope conditions,seasonality,and repeatability.At present,most related studies focus on the effects of rainfall on the shallow failure of expansive soil landslides.However,for large expansive soil landslides affected by reservoir water,the combined effects of rainfall and reservoir water on land-slide deformation and failure require further clarification.Therefore,investigating the mechanisms of instability and failure of expansive soil land-slides under the combined influence of rainfall and reservoir water level fluctuations is essential for implementing meteorological early warning,risk assessment,and engineering mitigation of landslides at the Danjiangkou Reservoir. Methods Using the Jingang Village landslide in Yunyang District,Shiyan City,a typical cross-section along the main sliding direction was se-lected to establish a two-dimensional slope experimental model based on a comprehensive analysis of geological surveys,GNSS monitoring,and data on rainfall and reservoir water levels.The model was vertically divided into the sliding mass,sliding zone,and sliding bed,while three addi-tional horizontal surfaces were arranged from the front edge to the rear edge.Each monitoring profile was equipped with moisture content sensors and pore water pressure sensors,and displacement sensors were installed on the surface of the landslide model.Based on the step-like deforma-tion characteristics of the landslide corresponding to fluctuations in reservoir water levels and rainfall conditions,and incorporating meteorologi-cal and hydrological data from the area surrounding the Jingang Village landslide,it was observed that the reservoir area experienced frequent heavy rainfall during periods of high water level operation and during phases of rising water levels.Three physical simulation experiments were designed.Condition one simulated the reservoir water level rising from low to high,remaining stable for a period,and then dropping back to a low level,with the cycle repeated several times.Condition two simulated continuous heavy rainfall during periods of high reservoir water level.Condition three was developed based on condition one and simulated continuous heavy rainfall while the water level rose from low to high.Real-time monitoring of the landslide failure process,including pore water pressure,moisture content data,and slope deformation,facilitated the inves-tigation of the instability mechanisms of expansive soil landslides under the combined influence of rainfall and reservoir water level fluctuations. Results and Discussions The main research content and results were summarized as follows:1)Model experiments showed that the failure pro-cess of the Jingang Village landslide manifested as tractional failure.The process began with localized deformation at the toe of the slope and then progressively developed upward,eventually leading to overall failure in the mid-front section.This process formed an open face and a steep step at the landslide fracture,followed by stepwise collapse;2)Reservoir water fluctuations and rainfall produced different response patterns in the internal pore water pressure and moisture content of the landslide.Only during fluctuations in the reservoir water level did the pore water pres-sure and volumetric water content at the front edge of the slope exhibit cyclic changes,while no response occurred at the middle and rear edges.After rainfall was applied,pore water pressure and volumetric water content outside the influence range of the reservoir water began to respond,increased with continued rainfall,and eventually stabilized.The increase in moisture content within the sliding zone was significantly higher than that at the slope surface,indicating that water ultimately accumulated near the sliding zone;3)In situ monitoring and physical model experiments demonstrated that a drop in reservoir water level produced sustained deformation at the front edge of the landslide.Rainfall caused overall defor-mation of the landslide,which was significantly greater than the deformation induced by the drop in reservoir water level.Landslides that experi-enced repeated cycles of rising and falling reservoir water levels were more susceptible to significant deformation under heavy rainfall conditions and could potentially become unstable;4)The continuous deformation of expansive soil landslides affected by the combined action of rainfall and reservoir water resulted from the dual effects of external added stress and the reduction of internal strength parameters.Persistent heavy rainfall rapidly infiltrated the slope body along fractures and raised the groundwater level,while the strength of the sliding zone soil continued to decrease due to prolonged soaking by groundwater.This process served as a key factor driving the continued deformation of large expansive soil landslides. Conclusions Based on the analysis of the deformation mechanism of expansive soil landslides under the combined effects of rainfall and reser-voir water,together with geological surveys and in-situ monitoring data such as rainfall,reservoir water level,and GNSS monitoring,and based on the analysis of landslide deformation characteristics,a physical model was designed and constructed.The changes in relevant landslide param-eters under different heavy rainfall and reservoir water conditions were monitored in real time,reflecting the deformation and failure mechanisms of expansive soil landslides under the combined effects of rainfall and reservoir water by installing sensors such as displacement,pore water pres-sure,and water content sensors.The findings provide reference significance for the study of expansive soil landslide failure theory and for practi-cal disaster prevention and mitigation efforts.关键词
膨胀土滑坡/变形破坏机理/物理模型试验/库水位升降/降雨Key words
expansive soil landslide/deformation failure mechanism/physical model test/reservoir water level fluctuation/rainfall分类
建筑与水利引用本文复制引用
黄晓虎,胡禹龙,郭飞,杨岚峣,邓茂林,肖宇煌..降雨及库水联合作用下膨胀土滑坡变形机理研究[J].工程科学与技术,2026,58(2):109-122,14.基金项目
国家自然科学基金青年基金项目(42007237) （42007237）
国家自然科学基金面上项目(42172303) （42172303）
三峡库区地质灾害教育部重点实验室(三峡大学)开放基金项目(2022KDZ16 （三峡大学）
2022KDZ14) （）
