考虑尺寸效应的小尺寸深基坑土压力与变形计算分析  

Calculation and Analysis of Soil Pressure and Deformation about Small Size Deep Excavation Considering Size Effect

作　　者：项龙江 龙照 时轶磊 叶帅华[3] XIANG Long-jiang;LONG Zhao;SHI Yi-lei;YE Shuai-hua(Gansu CSCEC Municipal Engineering Investigation and Design Institute Co.,Ltd.,Lanzhou 730000,China;CSCEC AECOM Consultants Co.,Ltd.,Lanzhou 730000,China;School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]甘肃中建市政工程勘察设计研究院有限公司,兰州730000 [2]中国市政工程西北设计研究院有限公司,兰州730000 [3]兰州理工大学土木工程学院,兰州730050

出　　处：《科学技术与工程》2020年第34期14178-14184,共7页Science Technology and Engineering

基　　金：甘肃省住房和城乡建设厅科研项目基金(JK2019-01)。

摘　　要：基坑侧壁土压力分布是深基坑支护设计的主要依据,对于进行支护结构设计具有重要的指导作用。主要考虑尺寸效应对基坑土压力与变形的影响,建立小尺寸深基坑主动土压力计算模型。通过假定滑裂面并采用极限平衡理论进行土压力计算。然后,借助PLAXIS 3D有限元软件建立不同平面尺寸与深度的基坑三维有限元模型,进行基坑侧壁土压力与变形计算。根据计算结果得出不同平面尺寸的基坑土压力与水平侧移变化规律。并将有限元计算结果与朗肯主动土压力理论计算结果进行对比。受尺寸效应影响,小尺寸深基坑的土压力减小,剪切破裂角不再是定值。研究结果将丰富小尺寸深基坑土压力计算理论,为此类基坑的支护设计提供参考。The distribution of soil pressure on the side wall of foundation pit is the main basis for the design of deep foundation pit support,which has an important guiding effect on the design of support structure.Therefore,the influence of size effect on soil pressure and deformation of foundation pit was mainly considered,and an active soil pressure calculation model of small size deep foundation pit was established.Moreover,the earth pressure was calculated by assuming the sliding surface and using the limit equilibrium theory.In addition,PLAXIS 3D finite element software was used to establish three-dimensional finite element models of excavation with different plane sizes and depths.The soil pressure and deformation on the side wall of the foundation pit was calculated.According to the calculation results,the change rules of soil pressure and horizontal lateral displacement of foundation pit with different plane sizes were obtained.The results of finite element calculation were compared with the Rankine active earth pressure theory.Affected by the plane size of foundation pit,the soil pressure of the small size deep foundation pit decreased significantly,and the angle of shear failure was no longer a constant value.The research results will enrich the theory of soil pressure calculation in small size deep foundation pit,and provide some references for the design of support of this kind of foundation pit.

关 键 词：基坑 土压力 水平侧移 尺寸效应 有限元法 

分 类 号：TU432[建筑科学—岩土工程]