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某公路开挖土质边坡降雨致灾机理数值模拟研究

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该文以大渡河上游某公路工程区一处降雨滑坡灾害为例,在进行灾后精细化调查的基础上,恢复边坡原始地形,采用数值模拟技术对开挖边坡渗流场与稳定性进行模拟计算,并阐明该滑坡在强降雨条件下的成灾机理.研究表明:该滑坡属于小型牵引式土质滑坡,沿基覆界面发生滑动,并由开挖临空面剪出.在强降雨作用下,原始斜坡渗流场变化显著,在坡表局部形成暂态饱和区,自重势能下孔隙水向坡脚汇集,也促使开挖坡脚处形成饱和区,而基覆界面附近形成的滞水带有助于坡体的蠕滑变形.随着强降雨的持续影响,块碎石土由非饱和逐渐发展至饱和状态,孔隙水的润滑、软化导致其力学强度衰减,加之工程开挖后抗滑段的缺失,最终坡体在自重作用下发生失稳破坏.这类降雨型滑坡在工程建设中极为常见,工程开挖后未处置或处置方式不恰当均可能会形成孕灾条件,通过对该案例的研究可为相似工程建设提供参考.
Numerical Simulation Study on the Mechanism of Rainfall Induced Disaster of Excavation Soil Slope in a Certain Highway
This paper takes a rainfall-induced landslide disaster in a certain highway engineering area in the upper reaches of the Dadu River as a case study.Based on detailed post-disaster investigation,the original topography of the slope is restored.Numerical simulation technology is employed to simulate the seepage field and stability of the excavated slope,elucidating the disaster mechanism of the landslide under heavy rainfall conditions.The study shows that the landslide is a small-scale cohesive soil landslide,sliding along the interface of the base covering and shearing out along the excavation face.Under the influence of heavy rainfall,significant changes occur in the original slope seepage field,with transient saturation zones forming locally on the slope surface.Gravity-induced pore water converges towards the slope toe,leading to the formation of saturated zones at the foot of the excavation.Additionally,the stagnant water belt near the base-covering interface contributes to the creep deformation of the slope.With the continuous impact of heavy rainfall,the broken stone soil transitions from unsaturated to saturated state.The lubrication and softening effects of pore water lead to mechanical strength degradation,combined with the lack of the anti-slide segment after excavation,ultimately resulting in instability and failure of the slope under self-weight.Such rainfall-induced landslides are common in engineering construction.Failure to address or improper disposal after excavation may create conditions conducive to disaster.The study of this case provides reference for similar engineering projects.

Excavated slopeBlock gravel soilHeavy rainfallNumerical simulationSeepage field

艾国海、向森川、李涛、孙亢、李世超

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中冶赛迪工程技术股份有限公司,重庆 400014

四川长昕建设工程有限公司,四川成都 610074

开挖边坡 块碎石土 强降雨 数值模拟 渗流场

2024

重庆建筑
重庆市建筑科学研究院

重庆建筑

影响因子:0.292
ISSN:1671-9107
年,卷(期):2024.23(5)
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