红层区残坡积土边坡降雨灾变机理及其工程防治  

Mechanism and engineering prevention of rainfall disaster in residual soil slope in red layer area

作　　者：杨华 李翔玉 Yang Hua;Li Xiangyu(Guizhou Zhengye Engineering&Technology Investment Co.,Ltd.,Guiyang 550002,China)

机构地区：[1]贵州正业工程技术投资有限公司,贵阳550002

出　　处：《工程勘察》2025年第5期35-42,共8页Geotechnical Investigation & Surveying

摘　　要：2022年7月中旬,黔北地区经历数日降雨,导致多地发生山体滑坡,其中工程开挖边坡破坏更为严重。本文以习水县北部山区某公路内侧一处红层残坡积土质滑坡为例,通过调查、试验、数值计算等手段对滑坡降雨成灾机理展开研究,并探讨此类滑坡工程防治方案。红层区残坡积层主要由粉质黏土组成,非饱和状态下土体结构中细颗粒收缩成团块,细观结构微调整促使摩擦强度降低,细颗粒、团块间孔隙水的润滑、软化加剧黏聚强度衰减,并最终形成黏聚力、内摩擦角与含水率之间的指数函数、幂函数关系。降雨过程中土体由非饱和向饱和状态转变,由坡表逐渐形成分散暂态饱和区并且范围持续扩大,这一过程中含水率的提高导致土体结构损伤、力学强度衰减,直至临界抗剪强度而导致边坡浅表层沿饱和深度界面附近发生滑动,多由开挖临空面剪出。根据研究对象及以往相似案例,红层区残坡积土质斜坡在降雨诱发条件下多表现为浅层破坏,而边坡防治应基于灾害统计的最大概率破坏深度进行针对性设计,防治方案以开挖放坡、挡土墙为主,部分高边坡可采用框架锚杆结合植草进行全坡面防护。研究成果不仅有助于提升当地防灾减灾能力,还可为相似地区降雨浅层滑坡灾害研究提供借鉴。In mid July 2022,the northern Guizhou region experienced several days of rainfall,leading to landslides in many areas,with the excavation of slopes causing more severe damage.This article takes a red layer residual soil landslide on the inner side of a highway in the northern mountainous area of Xishui County as an example.Through investigation,experimentation,numerical calculation and other methods,the mechanism of landslide rainfall disasters is studied,and the engineering prevention and control plan for such landslides is explored.The residual slope layer in the red layer area is mainly composed of silty clay.Under unsaturated conditions,fine particles in the soil structure shrink into clumps,and micro adjustments in the microstructure promote a decrease in friction strength.The lubrication and softening of pore water between fine particles and clumps intensify the attenuation of cohesion strength,and ultimately form exponential and power function relationships between cohesion,internal friction angle,and moisture content.During the rainfall process,the soil transitions from an unsaturated state to a saturated state,gradually forming a dispersed transient saturation zone on the slope surface and continuously expanding in scope.The increase in moisture content during this process leads to structural damage and mechanical strength attenuation of the soil,until the critical shear strength is reached,resulting in sliding of the shallow surface of the slope near the saturation depth interface,which is mostly cut out by the excavation face.Based on the study object and similar cases in the past,residual soil slopes in the red layer area often exhibit shallow damage under rainfall induced conditions.Slope prevention and control should be designed based on the maximum probability of damage depth according to disaster statistics.The prevention and control plan mainly includes excavation slope and retaining wall.For some high slopes,frame-anchors and grass planting can be used for full slope protection.The study results

关 键 词：残坡积层 粉质黏土 强降雨 致灾机理 工程防治 

分 类 号：TU411.92[建筑科学—岩土工程]