Performance of Cement–Soil Pile Composite Foundation with Lateral Constraint

Abstract

A lateral constraint can effectively reduce the foundation settlement and reduce the stress of a pile shaft in a foundation treatment. Based on the characteristics of railway engineering and soft soil engineering, this paper studied the influence that lateral constraint exerted on the stress and settlement of cement–soil pile composite foundation by using indoor large-scale model testing. A comparative analysis of the stress and settlement of cement–soil pile and soil following load change is performed, and the mechanism of lateral constraint is discussed. The results show that the settlement of the pile top with lateral constraint is 8–30% lower and that of the soil around the pile is 7–9% lower when comparing the settlement values of the composite foundation with and without lateral constraint in the cement–soil pile composite foundation. The stress value of the pile top in the composite foundation with the lateral constraint is 18–32% lower than that without any lateral constraint. The stress of the cement–soil pile shaft first increases and then decreases with the depth, and the maximum stress appears at 0.15–0.35 times the pile length from the top. The position of the maximum axial force of the pile without a lateral constraint is lower than that with a lateral constraint, and the maximum stress value of the pile is 112–153% of the stress value of the pile top. Therefore, setting the lateral constraint can effectively stop the lateral deformations of soft soil, reducing the settlement of the composite foundation and pile shaft stress.