Influences and mechanisms of anchor failure on anchored pile retaining system of deep excavations

Collapse accidents of excavations caused by anchor failure are common in anchored pile retaining excavations. Aiming at the problem, the finite difference method (FDM) is adopted to study the rules of load transfer, such as the earth pressure and the internal force of retaining structures of local anchor failure, and the corresponding model tests are designed. Failure of anchors will lead to obvious increase of axial force of adjacent 3~4 anchors, increase of the maximum shear force and bending moment of capping beams, and easy damage of capping beams according to structural reinforcement. As the number of failed anchors increases, the maximum load transfer coefficient (I_t) increases gradually and tends to be a constant value, and the deformation and stress mode of piles gradually transform from braced type to cantilever one. The maximum bending moment first decreases, then increases to a constant value. Meanwhile, I_m is generally larger than I_t. When the number of failed anchors is less, the failure will transmit along the anchor. When the number of failed anchors is more, the failure will develop to the pile. In addition, the larger the excavation depth, the lower the soil strength, and the higher the load transfer coefficient (I_m and I_t).