Research on Consolidation Characteristics of Composite Foundation in the Throat Area of a High-Speed Railway Station

Abstract

An experimental study on engineering characteristics of the thicker soft-soil composite foundation preloading was developed in the throat area of a high-speed railway station, which mainly includes variation of excess pore water pressure, settlement deformation, and pile-soil stress with time in different positions and depths. It can provide a theoretical basis for related engineering design and construction. Some consolidation characteristic laws of composite foundation were obtained: (1) Excess pore water pressure of composite foundation increases with the growth of load. After excess pore water pressure peak appears, it will disappear with time. The change of excess pore water pressure lags behind load. Excess pore water pressure obtained maximum value at the top of substratum, where additional stress is larger. With the growth of depth, excess pore water pressure decreases gradually in substratum. (2) Ground settlement and layered settlement have the same rule of 35 m pipe pile decreasing the settlement at the middle throat area of a railway station. The settlement obtained maximum value in the middle of the reinforced area with 25m CFG pile. (3) Pile stress, soil between piles stress, and pile-soil stress ratio have a decreasing trend from the center embankment to the edge. In the process of filling and preloading, stress transfers from soil to pile. Pile stress increases, and soil between piles stress gradually decreases.