有限宽度砂土密度对基坑受力及变形影响的模型试验研究

Model Experimental Study on Finite Width Sandy Soil Density on Force and Deformation of Foundation Excavation

以某地铁出入口基坑工程为背景,设计了3种不同砂土密度条件下的有限土基坑开挖室内模型试验,结合相应数值模型对比,对基坑有限土侧和半无限体侧的桩身水平位移、桩身弯矩及地表沉降进行分析。研究结果表明,随着砂土密度的增大,有限土侧和半无限土侧的桩身水平位移逐渐减小,水平位移与砂土密度呈线性负相关;随着砂土密度增大,两侧桩身弯矩沿桩身的变化曲线一致,有限土侧和半无限土侧的桩身弯矩逐渐减小;随着砂土密度增大,有限土侧和半无限土侧的地表沉降逐渐减小,地表沉降与砂土密度呈线性负相关;其影响范围约1.5倍的开挖深度,有限土侧地表沉降随砂土密度改变的变化速率均小于半无限土侧。

Based on the foundation excavation engineering of a subway entrance and exit,this paper designed three indoor model tests of finite soil foundation excavation under different sand densities.Combined with the comparison of corresponding numerical models,the horizontal displacement of pile body,bending moment of pile body and surface settlement of finite soil side and semi-infinite body side of the foundation excavation were analyzed.The results show that:With the increase of sand density,the horizontal displacement of pile on finite soil side and semi-infinite soil side gradually decreases,and the horizontal displacement is negatively correlated with sand density;With the increase of sand density,the bending moments of both sides of pile are consistent along the pile body,and the bending moments of finite soil side and semi-infinite soil side gradually decrease;With the increase of sand density,the land surface settlement on the finite soil side and semi-infinite soil side gradually decreases,and there is a linear negative correlation between land surface settlement and sand density.The influence range is about 1.5 times of excavation depth,and the change rate of surface settlement with the change of sand density on the finite soil side is less than that on the semi-infinite soil side.