Construction and Environmental Effect of MJS Pile Strengthening Soft Soil in Fuzhou Coastal Area

Combined with the first case of MJS construction method pile strengthening soft foundation in railway related project in Fuzhou coastal area, the construction process parameters of MJS construction method pile soft foundation reinforcement were summarized and put forward. Based on the cylindrical cavity expansion model, an axisymmetric finite element numerical model was established. The detailed analysis considered the deformation law of the soil on the pile side during MJS shotcrete pile forming. The results showed that the lateral displacement of the soil on the pile side generally presents a Z-shaped distribution. With the release of pressure during the gradual lifting of shotcrete pile, the positive displacement amplitude gradually decreases and the negative displacement amplitude gradually increases, And the maximum displacement position gradually moves upward. The analysis of the influence of shotcrete pressure showed that when the shotcrete pressure is 1.3p ~ 1.6p, the lateral displacement of soil is small and the deformation behavior is good; The surface settlement is small and consistent, and the ground pressure coefficient is reasonably controlled at 1.3 ~ 1.6. The measured value is close to the calculated value. The maximum lateral displacement and surface settlement account for 13.4% and 50.4% of the early warning value respectively. They belong to micro disturbance construction and fully meet the engineering requirements. In the process of shotcrete pile forming in the actual project, it is the key to control the internal shotcrete pressure when close to the surface, and the surface settlement caused by the interaction between shotcrete pressure and ground pressure should be paid attention to.