降雨强度对泥石流起动影响的模型试验研究  

Model test of rainfall intensity influence on debris flow starting

作　　者：周健[1,2] 杜强[1] 李翠娜[1] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《自然灾害学报》2016年第3期104-113,共10页Journal of Natural Disasters

基　　金：国家自然科学基金项目(41272296)~~

摘　　要：利用自制小比例模型槽,采用可控降雨强度降雨模拟器,进行了人工降雨诱发泥石流的室内模型试验,研究降雨强度对泥石流起动的影响,并确定泥石流起动的临界降雨强度。基于临界降雨强度下泥石流的起动过程,对孔隙水压力和坡体内部含水率的变化规律进行了研究,并与现场试验进行了对比。运用Geodog软件对泥石流形成前坡体的位移场进行了分析,研究坡体破坏规律。研究结果表明,泥石流起动的临界降雨强度范围为43～50 mm/h。泥石流发生前存在一个孔隙水压力增加的过程,在泥石流形成后,孔隙水压力急剧下降。降雨强度影响雨水在坡体内部的渗透,是泥石流起动的主要原因。泥石流起动与坡体含水率和饱和度的变化有关,当坡体饱和度超过80%时,产生整体滑动破坏,并迅速转化为泥石流。A laboratory experiment was carried out to study the debris flow induced by artificial rainfall. In this ex- periment, the influence of rainfall intensity on the debris flow starting was studied and the critical rainfall intensity of debris flow starting was determined using a self-made small-scale model flume and the rainfall intensity was con- trolled by an artificial rainfall simulator. The variation law of pore water pressure and water ratio in slope body was studied during the forming process under the critical rainfall intensity, the results were compared with those from field test. The displacement field before the forming of debris flow was analyzed by software GeoDog to study the failure law of slope body. Results show that, the critical rainfall intensities of debris flow starting range between 43mm/h and 50mm/h. The pore pressure increased before the forming of the debris flow, and falls dramatically af- ter its forming. The rainfall intensity influences the permeability of rainwater in the slope body, which was the main cause of the debris flow starting. The starting of the debris flow is related with the variations of the water content and saturation of the slope body. After the saturation exceeds 80% , integral sliding failure would be generated and the slope body would change into the debris flow rapidly.

关 键 词：降雨强度 泥石流 含水率变化 饱和度 

分 类 号：P64[天文地球—地质矿产勘探]