Three-Dimensional Numerical Analysis of Basal Heave Stability and Influencing Factors of Circular Foundation Pit Supported by Diaphragm Wall

Abstract

Circular underground continuous walls are widely used in deep and large excavation projects. The tensile stability is the main reason for the loss of strength and failure of continuous underground walls. A three-dimensional numerical analysis is conducted on the stability of a continuous wall bottom tube supporting a circular base hole using the strength attenuation method. Firstly, based on the foundation pit anchored by the Wuhan Yanglao Bridge as the engineering background, a finite element symmetrical axis was formed, which was created on the basis of the software PLAXIS. By reducing the shear force of the soil at the bottom of the hole, the shape of the sliding surface and the safety factor of the foundation were discussed, and stability failed. Then use FLAC 3D software to create a three-dimensional digital model. The following conclusion is drawn by changing the inner diameter of the foundation pit, the depth, thickness, and stiffness buried in the continuous underground wall. The thickness and stiffness of the lining, as well as the internal friction angle and soil adhesion. The tensile durability of circular continuous wall base holes is affected by the omnidirectional impact—safety factor obtained by the element method. The symmetry limit of the axis is higher than the safety factor given by two-dimensional plane analysis. As the inner diameter of the hole increases and the embedding depth, pad stiffness, internal friction, and adhesive force increase. Low sensitivity to changes in lining thickness and wall thickness. When using the strength attenuation method for finite element analysis Axisymmetric continuous wall base hole, circular guide, loss stability mainly due to the infiltration of plastic area, and soil at the bottom of the turn hole. The displacement of various feature points can serve as auxiliary guidelines.