Research On Bearing Characteristics Of Anti-slip Pile With Square And Round Cross Section Combined

The terrain in the western part of China is mainly mountainous,with more high and steep side slopes.Landslide disasters caused by slope instability occur frequently,resulting in huge property damage and human injuries.Anti-slip piles have been widely used in landslide management as an effective slope reinforcement measure.At present,the commonly used cross-sectional forms for the design of anti-slip pile structures are rectangular and circular.Among them,rectangular section anti-slip piles can provide larger bending stiffness and better anti-slip effect.However,its construction needs to be excavated into holes by hand,which is risky and long-period construction and has certain safety risks.Round section anti-slip piles can be mechanically formed,easy to construct and short construction period,but its flexural stiffness is limited.In order to combine the good anti-slip effect of rectangular section anti-slip piles and the advantages of circular section anti-slip piles for mechanized construction.In this paper,combining with the engineering background of a highway slope support,the anti-slip pile with square and round cross section combined is proposed.This form of anti-slip pile can ensure the anti-slip capacity,but also accelerate the construction efficiency and avoid the safety hazards caused by hand-dug construction.This form of anti-slip pile can ensure the anti-slip capacity,but also accelerate the construction efficiency and avoid the safety hazards caused by hand-dug construction.At present,this type of anti-slip pile has been tried in engineering,but its bearing characteristics still lack more systematic research.To this end,this paper uses indoor model tests and numerical simulations to conduct a more systematic research and analysis on the bearing characteristics and anti-slip effect of anti-slip pile with square and round cross section combined under different working conditions.The main research of the thesis is as follows.（1）Based on the design and calculation theory of traditional anti-slip pile.Considering the moment of inertia of the section of square pile section and round pile section and the calculated width of the pile.Theoretical calculation method of anti-slip pile with square and round cross section combined is proposed.（2）Indoor model tests of anti-slip pile with square and round cross section combined reinforced slopes were carried out.By measuring the pile top displacement,pile earth pressure and pile strain of five different pile length ratios of anti-slip pile with square and round cross section combined.The load displacement curve at the top of the pile,the pile earth pressure distribution law and the pile bending moment distribution law are analyzed and discussed.The load transfer and deformation characteristics of the anti-slip pile with square and round cross section combined were obtained.The results show that the bending moment and shear force of the anti-slip pile with square and round cross section combined are more complicated than those of the equal-section anti-slip pile,and there are abrupt changes at the section changes.（3）A three-dimensional finite element model of anti-slip pile with square and round cross section combined reinforced slope was established based on ABAQUS software.Using the strength reduction method,the influence law of different pile length ratios,different pile locations and other factors on the safety and stability coefficients of slopes was investigated,and the distribution law of soil pressure,pile bending moment and shear force along the front and rear of such anti-slip piles was analyzed.The effects of pile spacing,slope top loading and cross-sectional form on the slope reinforced by anti-slip piles were further analyzed.The load-bearing mechanism of anti-slip pile with square and round cross section combined is discussed.The results show that when the potential slip crack surface of the slope is within the length of the upper square pile section and the pile length ratio H₁/H is set to 0.5,the anti-slip piles have the best effect in strengthening the slope,taking into account the factors of material saving and slope strengthening effect.