竖向掏土纠倾孔周塑性区计算研究

Study of the calculation of plastic zone around the vertical digging hole for building rectification

采用桩筏基础的高层建筑倾斜后,常采用竖向孔掏土进行地应力解除实现纠倾,工程设计与施工依据经验进行,缺乏理论指导。将一定深度处的竖向孔孔周应力重分布问题简化为平面应变问题,采用摩尔-库仑强度条件推导了塑性区半径的解析解。该解析解表明,塑性半径随土体抗剪参数的降低而增大,随掏土孔半径的增大而增大,随地应力的增大而增大。结合解析解的表达式,探讨了存在地下水、注水、抽水、循环掏土扰动等因素对塑性区半径的影响。最后用数值分析方法对该解析解进行模拟验证,表明公式的正确性与适用性。该研究成果对纠倾工程的设计与施工具有积极的指导作用。

For inclined high-rise building with pile raft foundation, vertical hole digging is often used to relieve the ground stress to achieve the inclination correction. Due to the lack of theoretical guidance, the engineering design and construction have to rely to a large extent on experience. In this paper, the problem of stress redistribution around a vertical hole at a certain depth is simplified as a plane strain problem, and the analytical solution of the radius of plastic zone is derived by using the Mohr Coulomb strength theory. The analytical solution shows that the plastic radius increases with the decrease of shear parameters, the increase of digging hole radius and the increase of depth. By combining the site rectification phenomenon with the analytical solution formula, the influences of the groundwater, water injection, pumping, cyclic soil digging disturbance on the plastic radius are discussed. Finally, the numerical simulation is used to verify the analytical solution, which shows the validity and applicability of the formula. The research results will provide scientific insight for the design and smart construction of the rectification practice.