挡土墙后EPS颗粒混合轻量土填料静止土压力特性模型试验研究  

Model test on earth pressure at rest of light weight soil mixed with EPS particles behind a retaining wall

作　　者：侯天顺[1] 杨凯旋 HOU Tian-shun;YANG Kai-xuan(College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling,Shaanxi 712100,China)

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100

出　　处：《岩土力学》2021年第12期3249-3259,3270,共12页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51509211);中国博士后基金(No.2016M602863);陕西省留学人员科技活动择优资助项目(No.2018031);陕西省博士后基金项目(No.2017BSHYDZZ50);中央高校基本科研业务费专项资金项目(No.2452020169)。

摘　　要：为确定EPS(发泡聚苯乙烯,expandablepolystyrene)颗粒混合轻量土在挡土墙后的静止土压力特性,通过对素土和轻量土开展室外挡土墙模型试验,探究加卸载条件下土体在挡土墙后静止土压力、静止土压力系数、竖向沉降量的分布规律,揭示轻量土填料在挡土墙工程中的减压机制和沉降变形机制。结果表明:在加卸载之前,素土和轻量土的竖向土压力、侧向土压力随着填土深度的增加近似呈线性增加趋势,其理论值和实测值间的相对误差不大于26.35%。荷载对素土竖向土压力和侧向土压力的影响随着填土深度的增加而逐渐减小。轻量土养护成型后具有自立性,荷载对其影响深度有限,试验中轻量土的荷载影响区深度大致为H/2(H为墙高)。当填土深度小于H/2时,随着荷载的逐级增减,轻量土竖向土压力、侧向土压力增加和减小较为明显;当填土深度大于H/2时,竖向土压力、侧向土压力随着荷载的逐级增减逐渐出现收敛,变化幅度较小。素土与轻量土静止土压力系数在挡土墙后呈非线性分布,分别处于0.27~0.74和0.33~0.44范围内。由Jaky公式计算的轻量土静止土压力系数理论值基本大于试验实测值,但差值较小。素土的竖向沉降变形随填土深度的增加而逐渐减小,总体介于0~21.5 mm。而养护成型的轻量土在荷载的作用下,竖向沉降量变化不明显,总体介于0~2.8 mm。相比素土而言,由于EPS颗粒的缓冲作用以及水泥的固化作用,使养护成型的轻量土具有良好的缓冲性和自立性,可对竖向应力进行更有效的吸收和分散。轻量土可大大减小静止土压力、静止土压力系数和竖向沉降量,满足挡土墙工程中对填料减重增强的要求。To determine the earth pressure at rest of light weight soil mixed with expandable polystyrene(EPS) particles behind a retaining wall,the model tests are conducted for remolded soil and light weight soil respectively.The distribution laws of earth pressure at rest,coefficient of earth pressure at rest and vertical settlement deformation of the filler behind retaining wall are explored under loading and unloading processes,and the mechanisms of pressure reduction and settlement deformation of light weight soil are clarified.The results show that the vertical earth pressure and lateral earth pressure of remolded soil and light weight soil increase linearly with the increasing of filling depth before loading and unloading,and the relative errors between theoretical values and measured values for vertical earth pressure and lateral earth pressure are no more than 26.35%.The effect of load on vertical earth pressure and lateral earth pressure decreases with the increase of filling depth for remolded soil.After curing,light weight soil has self-supporting property,thus the influencing depth of load on light weight soil is limited.In this test,the load influencing area depth of light weight soil is about 50% of the wall height.In the process of loading and unloading,when the filling depth is less than 50%of the wall height,the vertical earth pressures and lateral earth pressures of light weight soil increase or decrease obviously with the gradual load increasing or decreasing.When the filling depth is greater than 50% of the wall height,the vertical earth pressures and lateral earth pressures gradually converge with the gradual load increasing or decreasing,but the change range is smaller.The measured coefficients of earth pressure at rest of remolded soil and light weight soil are non-linear distribution behind the retaining wall,which are in the range of 0.27-0.74 and 0.33-0.44,respectively.The theoretical values of the coefficient of earth pressure at rest calculated by Jaky formula are basically larger than the meas

关 键 词：轻量土 挡土墙 静止土压力 静止土压力系数 模型试验 

分 类 号：TU413[建筑科学—岩土工程]