Research On The Synergistic Mechanism Of The Newly-built Pile Sheet Wall And The Existing Cantilevered Retaining Wall

With the continuous improvement of the “eight vertical and eight horizontal” railway networks in my country’s mid-and long-term railway network,the number of newly built railway networks has increased year by year.Therefore,how to ensure the effective connection between the new lines and the existing lines,so as to give full play to the railway’s transport capacity and transportation capacity.Quantity is an issue that urgently needs to be considered in the field of engineering technology.For the reconstruction of the existing line and the addition of the second line,the multi-level combined block structure composed of multiple support forms can effectively solve the engineering problem of widening the roadbed.This paper takes the introduction of the Lanzhou hub supporting project of the Zhonglan Railway into the multi-type combined supporting structure of the subgrade slope as the research background,combining design data and on-site construction schemes,using theoretical calculations,indoor model tests,finite element numerical calculations and other research methods.Multi-factor analysis of the force and deformation of the combined support system composed of the newly-built pile-slab wall and the existing cantilever retaining wall is carried out to study the mechanism of its synergy.Through research,this article has mainly obtained the following research results:(1)Analyze the action mechanism and research status of the pile-slab wall,the cantilever retaining wall and the two-stage retaining wall composite retaining structure.It is found that the current composite retaining structure mostly adopts the two-stage cantilever retaining wall composite retaining structure.The research on the combined retaining structure of pile-slab wall and cantilever retaining wall has not been reported so far,so the study on the mechanism of synergy and the force and deformation of combined retaining structure has important theoretical value and engineering practical significance;(2)Summarize the commonly used earth pressure calculation theories,analyze the use conditions and scope of the Langkin theory and the Coulomb theory,combine the additional stress theory with the elastic theory,and apply it to the new pile-slab wall and the existing cantilever retaining wall.In the composite retaining structure formed by the wall,the earth pressure calculation model of the cantilever retaining wall in the composite retaining structure is deduced,and combined with the theoretical calculation and numerical analysis,the force and displacement of the cantilever retaining wall and the pile-slab wall are carried out.the study;(3)The indoor model test was carried out,and the horizontal displacement,vertical stress and horizontal earth pressure of the pile-slab wall and the cantilever retaining wall were measured through graded loading;the vertical stress and horizontal displacement of the pile body and the cantilever retaining wall were studied.With the changing law of the load,the comparison and analysis of the vertical stress on the front and back sides of the pile body change with the load and time,and the load sharing of the pile-slab wall and the cantilever retaining wall is calculated through the measured earth pressure.Ratio;using Madis GTS NX software modeling,analysis of the pile-slab wall-cantilever retaining wall under the action of the same level of load 54.1k Pa,the retaining structure deformation and the distribution of earth pressure,and the model test value and theoretical calculation solution Made a comparison(4)Through the study of the synergy mechanism of the combined retaining structure,this paper found that the pile-slab wall bears more earth pressure while the cantilever retaining wall bears less,but the support effect of the cantilever retaining wall is still obvious.The study also found that the use of a pile-slab wall-cantilever retaining wall and other combined supporting structures can effectively solve engineering problems such as embankment high-slope support and roadbed widening,while also saving construction land and costs.Therefore,the combined supporting structure was studied.So the research of gear structure is of great significance.