关键词: 高速铁路, 采空巷道, 桩板路基, 模型试验, 应力, 沉降

Abstract: The pile-plank structure, as a composite foundation for roadbed treatment in goaf, is still being held up by lack of recommendation and regulations. In order to study the behavior of this structure, the example of the Wufushan station in Hefei-Fuzhou high-speed railway was researched by model test; and then a series of data of pile axial force, soil pressure, and settlements of pile, bearing platform, soil, and goaf roof was obtained. Based upon the results of these data, an analysis of the variations of pile axial load, soil pressure, and settlement characteristics of this structure was conducted. Some conclusions are drawn as follows. (1) Under the effect of overlying load, the value of pile axial load presents a decrease as the increase of depth with its maximum appeared at the top of pile. The pile axial load along the sections distributed in goafs maintains constant as the increase of depth. (2) As the increase of depth, the skin resistance of pile also reduces along pile without negative value presented. The value along the sections in goafs is zero. (3) The variation of pile-soil stress ratio is similar to that of pile-soil load share ratio. The load shared by the pile firstly presents an increasing trend as the increase overlying load and tends to stable finally. (4) The settlements of bearing platform and soil among piles are even and small. There is almost no difference in the settlements in goafs and non-goaf regions, and almost no deformation occurred at the bottom of goaf roof . (5) Pile-plank has a good effect on reinforcement for goaf roadbed.

Key words: high-speed railway, goaf, pile-plank roadbed, model test, stress, settlement