Design and Deformation Monitoring Analysis of Large Crown Beam in Deep Foundation Pit

For pile+internal support, to reduce or avoid the use of side truss bracing and inclined bracing systems, a method of increasing the crown beam section was proposed to expand the main support spacing. This method can control the deformation of the foundation pit and ensure the safety and stability of the foundation pit. Based on the basic theory research of the design of the large crown beam, combined with the engineering case, the Lizheng software and MIDAS/GTS finite element software were used for calculation and analysis. The results indicate that the design of the large crown beam can effectively control the deformation of the foundation pit. By comparing and analyzing actual monitoring data, the feasibility and reliability of the design of the large crown beam have been verified. Adopting this support scheme can not only ensure the safety of the foundation pit itself but also ensure the normal use of surrounding buildings. Increasing the spacing between supports for earthwork and underground structure construction can shorten the project duration and reduce engineering costs, which has engineering application value.