Numerical simulation of the composite foundation of cement soil mixing piles using FLAC3D

In the road construction process often encountered in the construction of the phenomenon in the soft soil area, due to the physical properties of soft soil often can not meet the design requirements, it is often on the soft ground to add additives to achieve a more solid foundation. In order to compare the settlement of two different piles to determine a more suitable engineering method.The silty soft soil foundation of Xinxicheng Road was numerically simulated by the software of FLAC\(^\mathrm{3D}\), and a single-pile model was established to simulate the load test of single pile by loading load step by step. The resulting deformation grid diagrams of the cement soil mixing pile and cement sand soil mixing pile under loads of 300 kPa indicate that deformation gradually decreases from the center to the surrounding, and the maximum settlements of the two deformation maps were 19.36 and 13.60 mm, respectively. The relationships between maximum settlement and load show that the settlement values of the cement soil pile and cement sand soil pile were similar (within 1–2 mm of each other). The settlement value of the cement sand soil mixing pile was smaller than that of the cement soil mixing pile under large loads. Therefore, the use of cement sand soil piles can reduce the maximum settlement to meet engineering requirements. This paper provides a theoretical basis and guidance for the future treatment of soft ground deformation.