Optimization Of Anti Slide Pile Based On Soil Arching Effect

Anti slide pile is widely used in slope prevention and foundation pit protection because of its strong anti slide ability,good retaining effect,flexible pile position and easy construction.Since the beginning of the 20 th century,the theory of soil arching effect,which was discovered due to the "granary effect",has been put forward by Terzaghi and attracted the attention of geotechnical mechanics experts at home and abroad.At present,scholars at home and abroad have put forward many important theories about soil arching effect.However,because there are many factors that affect the soil arching effect,there is no consensus on the research of each factor and the reverse optimization of anti slide pile design.In this paper,aiming at the influence of many factors on soil arching effect,the theoretical analysis and numerical simulation of soil arching effect are carried out.Among them,the main influencing factors are pile spacing,soil shear capacity,cross-section characteristics of pile-soil interface and landslide thrust.The main conclusions and achievements are as follows(1)FLAC3D pile-soil model is established to discuss the influence of various factors on soil arching effect.Through the research on the influencing factors,it is shown that optimizing the influencing factors of soil arching effect can strengthen the soil arching effect in a certain range.The results show that: 11)The strength of soil arching effect increases with the increase of pile spacing.When the pile spacing is more than 5 times of pile spacing,the strength of soil arching effect begins to weaken;2)When the internal friction angle is between 15 ° and 25 °,the soil arching effect increases obviously.When the internal friction angle is greater than 25 °,the soil arching effect does not increase obviously.Similarly,when cohesion = 15 k Pa-25 k Pa,the bearing capacity of soil arching effect increases,but when cohesion is greater than35 k Pa,the effect of soil arching effect is not obvious;3)The stress in Y direction of different friction angles of pile-soil interface basically coincides,which indicates that the increase of friction angle of pile-soil interface is mainly to strengthen the friction arch,and has no great influence on the soil arch behind the pile;4)The strength of soil arching effect increases with the increase of landslide thrust.When the landslide thrust is 120 k Pa,the arch ring and arch ratio have great changes,showing the trend of weakening of soil arching effect.(2)by summarizing the soil arching effect between anti slide piles,the soil arching effect between anti slide piles in cohesive soil is analyzed from the aspect of mechanics.The mechanical balance force system before and after the pile,the action position of the arch foot and the failure condition of the soil arch are deeply studied.On this basis,two optimization factors are added,one is the reasonable arch axis with uniform stress,the other is the comprehensive thickness of soil arch ring.Based on the static balance force system and the most unfavorable section of arch foot,the formula of anti slide pile spacing is established,and verified by engineering examples,calculation results and simulation results.The results show that the optimized formula is more reasonable and more suitable for practical engineering application.