The Study On Mechanical Mechanism Of H-type Anti-slide Piles And Its Engineering Applications

The landslide disasters threaten the life and property safety, hindered the development of social economics. Scientific and rational evaluation of slope stability, safe and reliable design of slope reinforcement engineering is still a difficult point in the process of infrastructure construction. Double row anti-sliding piles as a new type of retaining structure, its mechanical mechanism is relatively complex than single row pile, and the research about retaining piles in foundation pit engineering is more than anti-sliding piles in slope supporting. The mechanical mechanism of h-type anti-sliding piles as improved form of portal double row piles is different with it, and its theoretical research has lagged behind the practice. In this paper, the mechanical mechanism of h-type anti-sliding piles will be studied by theory analysis, model test, numerical simulation and engineering application. The main works and achievements of the thesis can be drawn as follows:①The slope pressure acting on h-type anti-sliding piles and structure calculation model are analyzed systematically. Transfer coefficient method and strength reduction FEM for landslide thrust calculation, fore-back pile calculation model and up-down part calculation model for structure calculation are described, and the best mothed is put forward based on analyzing the advantage and disadvantage of different methods. Then, cantilever beam method for computing the internal force of rigid anti-sliding pile anchorage section is put forward. Finally, the principal for anchorage depth design of half-slope h-type anti-sliding piles is suggested, in which the anchorage depth must meet the requirements of ultimate bearing capacity and shear bearing capacity. Then the check formula for meet shear bearing capacity is proposed.②Now, the distribution of landslide thrust is according to stratum properties only, this is not true in reality. Therefore, the model test of h-type anti-sliding piles with different row distance and anchorage depth was performed. The results show that the distribution of landslide thrust is related to pile’s resistance ability of lateral deformation, variation of slope preesure acting on h-type anti-sliding piles is concluded, and the corresponding pressure distribution function is presented.③Based on the model test, interaction mechanism between h-type anti-sliding piles and landslide is studied by numerical simulation. The landslide thrust resistance mechanism of anti-sliding piles and rock-soil mass around pile is analized, and the design proposals of h-type anti-sliding piles is suggestted.④In order to optimize the h-type anti-slide piles, the influence of pile parameters to performance of h-type anti-sliding piles are analyzed based on numerical simulation. The row distance, cantilever length, anchorage depth of back pile, anchorage depth of fore pile and relative rigidity of crossbeam are analyzed emphatically, and the corresponding suggested values are given.⑤According to the geological conditions of Jing-Xing mine dump slope project. Firstly, the safety factor formula for layered soil slop is proposed based on upper-bound theorem of limit analysis. Then, the bearing capacity of single row pile, unconnected double-row piles and h-type anti-sliding piles are compared, and the h-type anti-sliding piles is proved suitable for this project. Finally, the stability of strengthened slope, bearing capacity mechanism of h-type piles and anchorage depth are analyzed, it shows that the optimization design is reliable.