恒定渗流作用下泥石流起动过程冲刷试验分析  

Experimental analysis of scouring of debris flow initiation process under steady seepage condition

作　　者：杨顺[1,2] 欧国强[1] 王钧[1,2] 陆桂红[1,2] 宇岩[1,2] 潘华利[1] 

机构地区：[1]中国科学院水利部成都山地灾害与环境研究所山地灾害与地表过程重点实验室,成都610041 [2]中国科学院大学,北京100049

出　　处：《岩土力学》2014年第12期3489-3495,共7页Rock and Soil Mechanics

基　　金：水利部公益性行业科研专项经费项目资助(No.201301058);中国科学院山地灾害与地表过程重点实验室自主项目资助;国家自然科学基金项目:恒定非均匀泥石流坝后冲刷动力过程与机理研究(No.41372331)

摘　　要：渗流是泥石流水动力条件主要来源之一,不同渗流流量具有不同的渗流力和冲刷力,从而可引起不同规模泥石流。通过开展室内水槽试验,利用测压管量测渗流过程中的孔隙水压力,并结合高清摄像技术从微观角度记录堆积土体内部细颗粒的运移、骨架颗粒的坍塌现象,以此分析研究土体渗透破坏、起动形成泥石流过程中的渗流和冲刷作用。在此基础上设定水槽坡度为7°,调节恒定渗流流量分别为120、170、265、320 ml/s,分析不同恒定渗流流量对固体堆积物失稳、泥石流起动过程中流态变化的影响。分析结果表明,在恒定渗流流量作用下,堆积土体内部细颗粒迁移、骨架颗粒坍塌造成土体颗粒重排列、孔隙水压力上升进而导致土体抗力降低是泥石流土体颗粒失稳、起动、冲刷的重要原因;随着渗流流量增加,流速迅速上升,土体内孔隙水压力逐步增大,骨架颗粒的失稳、移动主要受渗流及水流冲刷两方面共同作用,堆积土体颗粒的移动分别表现出缓慢小幅滑动后稳定、过渡型滑动和快速流滑现象。Seepage flow is one of the mainly hydraulic conditions for debris flow, different seepage discharges possess various seepage forces and scouring abilities which can induce different scales of debris flow. Through flume experiment, this study measures the pore water pressure by piezometer tube at three cross-sections, records the movement of fine particles and collapse process of coarse particles by high definition camera technology in micro respect, which is used to analyze the soil seepage fail and scouring effect in the process of debris flow formation. On this basis, conducting the experiment on fixing the slope angle of flume device is 7 degree and regulates the constant seepage flow discharge of 120, 170, 265 and 320 ml/s respectively, it analyzes the effect of the flow state on soil particles failure and debris flow initiation under different seepage flow discharges. The results indicate that the migration of fine sand particles and collapse of coarse particles which lead to the rearrangement of the soil structures and enlargement of the pore water pressure, are the important reasons for soil particles failure, initiation and scouring by low soil resistant; with increasing of seepage flow discharge, the flow velocity and pore water pressure increasing rapidly, it attained that thecoarse particles fail to move are mainly affected by seepage force and flow scouring. Meanwhile, the movement of the soil particles and water flow shows three different flow states, i. c. presented slightly slide, transitional slide and rapid slide.

关 键 词：恒定渗流 泥石流起动 孔隙水压力 冲刷 水槽试验 

分 类 号：P642.23[天文地球—工程地质学]