某公路开挖土质边坡降雨致灾机理数值模拟研究  

Numerical Simulation Study on the Mechanism of Rainfall Induced Disaster in Soil Slope Excavation of a Highway

作　　者：艾国海 向森川 李涛 孙亢 李世超 Ai Guohai;Xiang Senchuan;Li Tao;Sun Kang;Li Shichao

机构地区：[1]中冶赛迪工程技术股份有限公司,重庆400014 [2]四川长昕建设工程有限公司,四川成都610074

出　　处：《重庆建筑》2024年第5期51-54,共4页Chongqing Architecture

摘　　要：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。This paper uses a rain-induced landslide disaster in a road engineering area in the upper reaches of the Dadu River as an example.Based on detailed post-disaster investigation,it restores the original slope topography and uses numerical simulation techniques to calculate the seepage field and stability of the excavated slope,thereby explaining the disaster mechanism of the landslide under heavy rainfall conditions.The study shows that the landslide is a small-scale traction type soil landslide,occurring along the base-cover interface and shearing out from the excavated exposed face.Under the influence of heavy rainfall,there is a significant change in the original slope seepage field,forming transient saturated zones on the slope surface.Pore water converges at the foot of the slope due to gravitational potential energy,facilitating the formation of saturated zones at the foot of the excavated slope.The water-retention zone near the base-cover interface helps induce creep deformation of the slope.As the heavy rainfall continues,the blocky gravel soil transitions from an unsaturated to a saturated state,resulting in a decline in its mechanical strength due to lubrication and softening of pore water.The lack of an anti-slide section post-excavation also contributes to the eventual instability and failure of the slope under its own weight.This type of rain-induced landslide is very common in engineering construction.Failure to handle post-excavation or improper handling methods can create hazardous conditions.The study of this case provides valuable reference for similar engineering construction projects.

关 键 词：开挖边坡 块碎石土 强降雨 数值模拟 渗流场 

分 类 号：P642.22[天文地球—工程地质学] U416.14[天文地球—地质矿产勘探]