Adjacent To The Operating Line Of High-speed Railway Lightweight Foam Concrete-covered Wide Roadbed Numerical Simulation Of Deformation Characteristics

At present,there are few technical researches on subgrade construction under the condition of busy high-speed railway operation in China.Traditional help wide high-speed railway subgrade ontology often take material,with the existing roadbed gravel soil improvement AB group classes or grading mixed packing,such packing heavy is big,high bearing capacity of foundation,significantly increase of existing in the high fill subgrade engineering side bias load,easily causes subgrade has obvious uneven settlement,endanger the safety of train.China introduced and developed foamed lightweight soil technology in 2002.The material has the characteristics of light weight,high strength,excellent self-support and pumpability.It has been widely used in road widening,soft foundation and permafrost treatment and has achieved good benefits.The application of foamed lightweight soil in the wide subgrade of high-speed railway can give full play to its material properties and reduce the uneven settlement caused by the bias of the existing subgrade.Compared with highways,the filling height of high-speed railway subgrade is often larger,the structure is more complex,and the ride comfort requirements are more strict.At present,only a few scholars have studied the application of foamed lightweight soil in railway subgrade engineering,and the relevant research results are few,and the existing results are difficult to be directly used to solve the problems of high-speed railway subgrade widening engineering.Therefore,in order to ensure the construction quality and safety,the deformation characteristics of the new and old subgrade must be considered.In this paper,a large number of domestic and foreign researches on foamed lightweight soil were reviewed,and the physical properties,mechanical characteristics and quality control were systematically reviewed.Based on the actual project,the numerical calculation combined with construction monitoring means is used to study and analyze the deformation characteristics of the roadbed with foamed lightweight soil filling and its significant advantages compared with the conventional AB material.Finally,based on numerical calculation,the main influencing factors of deformation of the high speed railway embankment are calculated and analyzed.Specific research contents are as follows:(1)A review of the properties of foamed lightweight soil materials:By domestic and foreign research results and literatures,the performance of foamed light soil materials were reviewed systematically,including the material physical properties(apparent),density,mechanical properties,the constitutive relation,intensity,etc.)and durability(permeability resistance and freeze resistance,fatigue resistance,etc.)characteristics of the summary,and bubble of lightweight soil for wide of high-speed railway subgrade construction quality control points.(2)high speed railway bubble deformation characteristics of lightweight soil for wide subgrade numerical calculation: based on actual project,using the finite difference software FLAC 3 d,analysis and research in the neighboring line operating condition,help wide subgrade ontology using conventional AB group packing two kinds of packing,and bubbles of lightweight soil subgrade basement subsidence,both new line bed sedimentation and three rules of deformation law of the retaining wall lateral;Furthermore,the subsidence and deformation characteristics of roadbed under the action of train are calculated and analyzed with ANSYS.(3)Analysis of settlement and additional stress of foamed lightweight soil:DCM settlement monitoring equipment and earth pressure box were buried in the section with the maximum filling height,and the basement settlement and earth pressure data of the wide subgrade under different monitoring sections were collected regularly.By analyzing the relationship curve between the monitoring value and the filling height and time,the subgrade deformation and pressure value variation rule characteristics during the filling process of the wide subgrade with foam light soil wall were studied.(4)Analysis of the influencing factors of the deformation of the wide embankment of high-speed railway: Based on the numerical simulation method,the foundation settlement of the wide embankment under different parameters of pile diameter,pile distance and the thickness of the retaining wall,the settlement of the existing line bed and the lateral movement of the retaining wall are calculated and analyzed,and the influence law and sensitivity of each parameter on the three kinds of deformation are summarized.