Numerical analysis of soil nailing's instability in deep foundation pit

This paper applies FLAC(3D) software to simulate and analysis deep foundation pit design based on some unstable situation such as the top soil body of side slope dehiscence and the base soil body of side slope collapse appeared in substep excavate and support by soil nailing in deep foundation pit located on Beijing of fang shan magmatic university city building design. Apply Mohr Coulomb elastic-plastic model in numerical simulation to compute side slope's displacement deformation indifference steps, then acquire displacement deformation cloud atlas of the whole deep foundation pit and the maximal displacement cross-section through post-processing method, comparing numerical simulation result with reality measured data to determine the approximate state of potential sliding surface and collapse in deep foundation pit. Furthermore, it could offer some important reference for improving support pattern of major displacement area in design programme.