Study On The Anti-slide Mechanism And Design Method Of Small-diameter Steel Pipe Composite Structure

Quick construction of small-diameter steel pipe composite structure,easy to coordinate with the engineering geological and ecological environment is very suitable for controlling engineering landslide hazard under ambient conditions in complex.Because of complexity and variability of the pile of rock and soil,the effect of steel pipe pile in the composite structure of the soil,the lack of systematic research and awareness of the mechanism of the pile group and anti-sliding retaining wall design theory,makes theoretical research lags behind engineering practice greatly.In this paper,a combination of small-diameter steel pipe reinforced for Longhui 3(5)Well Station landslide as the research object,analysis of its engineering geological characteristics,causes and prevention measures,build a small-diameter steel pipe with a combination of anti-slide pile landslide interaction mechanical model,on the basis of the different arrangement of small diameter steel pipe piles against sliding structure physical model test,obtained before and after pile,soil stress,strain and displacement of pile head of pile dataof pile of data to study the steel pipe pile by deformation characteristics and load transfer between pile and soil.Then,a numerical simulation of the physical model of steel pipe pile to analyze the overall displacement of the landslide,the distribution of the pile shear and bending moment,the group piles spacing soil arching form,the change of landslide sliding,compare physical models and numerical simulation results,the mechanical properties of different forms of arrangement of steel pipe pile structure and how it works,it is determined at different landslide thrust,and most anti-slide pile spacing of steel pipe pile structures.Through the typical engineering examples.Longhui 3(5)Well Station landslide numerical simulation,further verify the sliding resistance mechanism of steel pipe piles.Finally,combining the basic theory of structural mechanics,the mechanics model and calculation method of steel pipe pile groups for steel pipe pile design provides valuable theoretical basis.The steel pipe pile structure optimization model will be applied on the outside of Longhui 3(5)well station landslides and Nano lines 46#landslide prevention,analysis the stress and deformation characteristics of steel pipe pile,reinforcement safety factor and landslide displacement,verify the feasibility and effectiveness of steel pipe pile structures.The main research results are as follows:(1)The steel pipe composite structure of the force during the anti-slide deformation can be divided into three stages:no deformation stage~elastic skid stage to the elastic-plastic failure stage.(2)When the pile spacing is less than 7d,between the steel pipe pile group should be established no significant displacement and arch arch produce,soil arching effect basically does not exist.When the pile spacing is 7-10d,the steel pipe pile group can better produce the displacement and stress arch arch,soil arching effect is remarkable,especially in the pile spacing 7-8d best.And later when the pile spacing exceeds 10d,steel pipe pile group can form stress arch,but the soil between piles have a"Slalom"campaign.(3)The steel pipe pile groups subjected landslide thrust gradually decrease along the sliding direction,and each row of piles by the landslide thrust triangular-quadrilateral composition distribution.(4)By the dutch section of the pile bending moment concentrated in the sliding surface over 1/3 of pile length range,pile anchorage section also bear a greater moment,and the moment in the opposite direction by the load segment.(5)Strength of pile body and the landslide thrust under the same premise,with the increasing pile spacing,pile bending moment of each pile showed an increasing trend,which indicates that the smaller pile spacing,pile binding effect on the soil between piles stronger,the soil between piles share more landslide thrust,the anti-sliding ability of steel pipe pile group is also higher.(6)Based on the steel pipe pile,pile soil interaction and the associated longitudinal beams form a"pile-soil complex"and"shear soil"pile row between the resistance generated as part of the overall anti-slide structure stabilizing force,the rest of the sliding force by the combination of steel stabilizing piles bear,establish a steel pipe pile shear formula,which(7)Based on the results of model tests and numerical analysis,considering the connecting beam occurs only horizontal displacement,pile top corner is zero,steel pipe pile displacement formula is established,which(8)Regardless of the tensile stress of soil between piles,based on the principle of the soil arch effect,establish the formula of the steel pipe pile spacing,which(9)Considering the influence of pile spacing of pile soil and introducing the influence coefficient of pile spacing,steel pipe pile bending moment correction formula is established,which...