Mechanical properties of gravity anchored foundation for large rectangular pipe jacking

With the increasing of pipe jacking section size, the demand for jacking force is also increasing in pipe jacking projects.Since the coastal soft soil is characterized by low bearing capacity and high compressibility, the traditional backseat wall can not provide sufficient push-back force in coastal soft soil area and not suitable for the pipe jacking projects in this area.Therefore, aiming at the pipe jacking projects of coastal soft soil area, a new type of reaction structure, gravity anchorage foundation was proposed.A three dimensional finite element analysis was used to simulate the gravity anchored foundation in the construction stage of pipe jacking, so the mechanical properties of the gravity anchored foundation was obtained.The results show that push-back force can cause local stress concentration and non-uniform deformation of the foundation slab.Gravity anchored foundation uses the combined structure of foundation plate, dowel, anchor and composite foundation to effectively offset the push-back force and control the displacement and deformation of foundation plate.Gravity anchored foundation would lose friction due to upward bending deformation of foundation plate, and anchored bars were used to control the bending deformation.The results can provide reference for the design of the novel gravity anchorage foundation.