泥石流“锚杆-护坡”防治模型试验宏细观机理

Macro-micro Mechanism and Experimental Research of “ Anchor-Slope Protection ” of Debris Flow

通过滑坡型泥石流'锚杆-护坡'防治室内模型试验,分析了泥石流防治的宏细观机理.试验结果表明,雨水渗出量和降雨量差异造成孔隙水在坡体内积蓄、孔隙水压增高,但坡体未出现分层滑动现象,仅发生了入渗软化和小规模蠕动.细观机理分析表明,坡体中水土细观运动分为'水在颗粒中渗透'和'颗粒在水中浮动'2种模式,细颗粒随雨水渗流在颗粒骨架间下沉并发生平行于坡底的运动,最后因'锚杆-护坡'的滤水固土作用而逐渐沉积并保持稳定.试验宏细观分析表明:颗粒的细观运动改变了模型试验坡体的破坏机理,坡体结构由不同粒径颗粒均匀分布变为'底部细颗粒积聚密实,上部粗颗粒骨架稳定'结构,降低了滑坡型泥石流的发生概率.

A model test was carried out to study the macro-micro mechanism of the debris flow prevention by using＂anchor-slope protection＂.The experiment result indicates that the exudation amount of rain water leads to pore water pressure increase,retrogressive toe sliding is not found during the experiment,and the experimental slope has infiltration softening and small-scale peristalsis.The micro-analysis indicates that the water-soil movement in slope has two forms,＂water seepage among particles＂and＂fine particle float in water＂,and the fine particles drop down with seepage water and float among grain skeleton with flowing water.As last,the fine particles were accumulated at the base of slope at the work of＂anchor-slope protection＂.Macro-micro experimental analysis indicates that particle micro-movement changes the structure of the slope as the relative stable structure of＂fine particle drop to the bottom and compaction,the upper coarse particle skeleton is stable ＂ is formed,and this stable structure reduces the incidence of debris flow.