西江引水工程顶管顶进工作井及土体稳定性分析

以西江引水顶管工程为背景,借助有限元软件对其施工过程进行了三维数值模拟,探讨了顶管施工过程中工作井与土体受力变形特性及稳定性,工作井模拟中考虑钢筋与否的影响,千斤顶压力对井和土层受力变形的影响。研究表明:井后土层最大应力出现在垫板后,竖向位移呈现类似Peck沉降槽;土层水平位移在竖向近似线性分布,横向在1.5倍垫板宽度范围内迅速衰减,该范围外衰减值显著减小;工作井、钢筋最大应力均出现在井与管的连接处,工作井局部开裂,但处于安全状态;土压力理论计算被动土压力与数值计算反力比值满足稳定标准,土体处于稳定状态;数值计算中考虑钢筋与否对土层结构受力变形影响甚微;土层、工作井受力和稳定性均与千斤顶压力近似呈线性关系。

Analysis on Stability of Work Well and Soil in Xijiang River Water Diversion Project

Taking the Xijiang River Water Diversion Project as background, an elasto-plastic simulation is carried out with FEM program to analyze the force, deformation and stability of work well. The influences of working well simulated with steel bar or not as well as the influence of jack pressure on the soil and well were explored. The results indicate that the maximum stress of soil appears on the plate after the well and vertical displacement appears, similar to Peck settling tank. The vertical distribution of horizontal displacement is approximately linear, and the speed of attenuation is relatively fast within the scope of 1.5 times of plate width and attenuation decreases significantly outside 1.5 times of plate width.The maximum stress of the well and steel bar appear in the connection parts of well and pipe,so the well is locally cracking, while the structure is in secure state.The ratio between theoretical calculation of the passive earth pressure and the corresponding force of numerical calculation meet the stability criteria, so the state of soil is stable. In calculation, considering reinforcement or not has little effect on the stress and deformation of soil and well.The relationship between the force, deformation and stability of soil and jack pressure is approximately linear, so is for the working well.