Based on Abaqus Finite Element Analysis Software to Assist the Construction of Super Large Caisson

Convex” caisson is to design caisson into a non-round, non-rectangular, non-square plane shape, forming a convex plane structure form. This kind of caisson is more difficult to make than regular caisson, and because of the uneven and asymmetrical distribution of body weight, it is easy to cause the well body to skew in the sinking stage, which puts forward higher requirements for subsidence control, and the difficulty of deviation correction is also higher than ordinary regular caisson. From the three aspects of sinking process control, construction process optimization, whole process numerical simulation, the whole process of caisson construction process control and monitoring. The settlement accuracy is controlled and the disturbance to surrounding soil is reduced by installing brake pile at the edge foot, maintaining steel sheet pile and sealing the bottom of high-pressure jet grouting pile. Adjusting the sinking times and sinking depth of caisson by optimizing the technological process; The deformation and stress concentration of caisson and surrounding soil were analyzed by numerical simulation, and the numerical simulation calculation results were verified by monitoring in the construction process to ensure the construction effect and safety.

I. Introduction

Caisson is one of the common construction methods of coarse grid and inlet pump house, which is widely used in the field of underground construction engineering. The difference of geological conditions often leads to the phenomenon of sudden subsidence and attitude tilt in the sinking operation of caisson, and has an impact on the surrounding environment. Around some problems existing in caisson, scholars at home and abroad have carried out many studies from different perspectives such as field monitoring, laboratory model test, theoretical derivation and numerical simulation [1]–[5]. Zhu Jinsong [6] monitored the whole process of sinking of caisson in real time, and systematically studied the change law of lateral friction, position distribution of peak resistance, relaxation height and subsidence coefficient. Shi Lianghong [7] calculated and analyzed the structural mechanical characteristics of caisson at each stage of sinking, and proposed construction control countermeasures such as uniform excavation and sinking, central soil support, air curtain and water jet to help sinking, and prestressed steel beam to enhance crack resistance. Lu Hao [8] summarized the variation law of surrounding soil surface settlement, deep soil horizontal displacement and pipeline settlement during the sinking process of caisson by numerical analysis, and proposed targeted reinforcement measures.