搅拌桩加固河堤的变形破坏离心模型试验

Centrifugal model test on deformation failure of riverbank reinforced by mixing piles

为验证南水北调工程安徽段-白山枢纽工程搅拌桩加固河堤的安全性,采用离心模型试验方法研究了高重力场下河道水位、河堤表面沉降、不同位置桩土的受力与变形性状及河堤的变形破坏模式。结果表明,土体中自由水通过破坏后的桩体排出导致河道水位上升。一级坡顶沉降最大,最危险滑动面剪入口位于一级坡中部,除最危险滑动面以外的地基中仍然有潜在的滑体和滑动面存在。离心加速度升至80 g时,河堤发生深层滑动失稳破坏。失稳破坏过程中,一级坡顶下桩体表现出受压受剪破坏,一级坡面及二级坡顶下桩体表现为压弯和拉弯破坏,二级坡面至河床下的桩体表现为剪切破坏。地基滑动面并未完全穿过桩体破坏位置。

In order to verify the safety of the riverbank reinforced by mixing piles in Anhui section of the South-to-North water diversion project(Baishan junction project),centrifuge test was carried out to study the riverway water level,riverbank surface settlement,stress and deformation properties of piles and soil at different positions,and the deformation and failure modes of riverbank under high gravity field.The results show that the free water in the soil was discharged from the damaged piles and the water level of the riverway increased.The first crest of riverbank exhibited the largest settlement,and the shear entrance of the most dangerous sliding surface was located in the middle of the first slope.Besides the most dangerous sliding surface,there were still potential sliding bodies and sliding surfaces in the foundation.When the centrifugal acceleration rised to 80 g,the deep sliding instability failure of the riverbank occurred.In the process of riverbank failure,the columns under the first crest of riverbank were compressed and sheared to failure.The columns under the first slope and the second crest of riverbank presented bending failure.The columns under the second slope of riverbank were sheared to failure.The slip surface did not completely pass through the failure positions of columns.