Effect of reinforcement of deep mixing piles on deformation of ultra-deep excavations in passive zone

By selecting different parameters of reinforced soil and adopting hardening-soil finite element model based on unloading, the influence of bottom soil on deformation of excavations is studied. The results show that the reinforcing influence on lateral deformation increases with the increase of the excavation depth, and the final lateral deformation can be reduced by 27%. This effect is prominent for controlling the uplift in bottom soil around retaining structures, and the utmost inhibition of uplift may exceed 50%. The influence of reinforcement on soil settlement behind the retaining structures is conspicuous, about 60% in local zone. Therefore, selecting a rational reinforcing form based on different geological conditions and deformation requirements is needed to make the reinforced soil intensity reach the design demand, which can guarantee the excavation safety and environment impact and save the engineering cost.