Authors:
Xuansheng Cheng; Wanlin Zhang; Wanxi Zha; Yingchao Zhou; Lijun Gong;
Abstract:
At present, there are few studies on bearing characteristics and settlement laws of composite foundations in collapsible loess areas. Taking long and short pile-net composite foundations (CFG pile refers to Cement Fly Ash Gravel long pile and CSC pile refers to Cement-Soil Compacted short pile) in collapsible loess area of Yinxi high-speed railway as the research object, three-dimensional numerical simulation is carried out on long and short pile composite foundations by finite element method. Then, mechanical characteristics and settlement
laws of long and short pile-net composite foundations are studied. The conclusions are as follows: under the loading of the embankment, the CFG pile mainly bears most of the load; at the same height within the
embankment, especially near the centerline of the embankment, the vertical pressure at the pile top is greater than that of the soil between the piles, and the vertical stress difference between the pile top and the soil between the piles along the embankment slope direction (namely, away from the embankment centerline) gradually
decreases; the maximum lateral displacement of the composite foundation occurs at the embankment slope; the settlement deformation and vertical displacement of the overall foundation, the soil between the piles and the pile body are gradually reduced from the embankment centerline to the embankment slope; the settlement deformation of the CFG pile is relatively smaller. The results of numerical simulation analysis are basically consistent with those of the test section. This paper is a research based on a real engineering project and can
provide some critical references for the design and construction of other similar engineering cases in the future.
Keywords:
Collapsible loess, Pile-net composite foundation, Numerical simulation, Mechanical characteristics, Settlement laws.