Research On Engineering Characteristics Of Foam Light Soil And Modification Of Latex Powder

As a new type of roadbed material,foamed lightweight soil has the advantages of light weight,good fluidity,convenient construction,and low environmental impact.It has a wide range of applications in road expansion,bridge abutment backfill,high railway foundation,cavity filling and underground structure load reduction.At present,the research on foam light soil mainly focuses on the basic properties and construction technology.The research on its mechanical mechanism and related theories is still insufficient,and the preparation process is not standardized.Therefore,it is necessary to conduct in-depth and systematic research on the preparation,mechanics and deformation characteristics of foamed lightweight soil.In this thesis,the method of indoor test is used to study the preparation technology,physical and mechanical properties,deformation performance of foamed lightweight soil,and the numerical simulation method is used to compare and analyze the deformation characteristics of foamed light weight soil and conventional fill subgrade.The research content and results are as follows:(1)Select the raw materials required for the foamed lightweight soil,study the preparation process and related parameters of the foamed lightweight soil,and obtain the optimized filling sequence and mixing time and other parameters.Using this process,280k N/m~3～780k N/m~3can be continuously prepared.Foam light soil with stable performance.(2)Using the method of orthogonal test,the influence of foaming agent content,water-binder ratio,and expanded perlite content on the density,unconfined compressive strength and flexural strength of foamed lightweight soil was studied,and the results were obtained.Optimum mix ratio of foamed lightweight soil with dry density of about 550k N/m~3.The relationship between the density,age and strength of the foamed lightweight soil was established,and the deformation law of the compressive stress-strain curve of the foamed lightweight soil was discussed.(3)Based on the above-mentioned optimized mix ratio,an experimental study of foam light soil modified by latex powder was carried out,and the changes of physical mechanics and deformation properties of foam light soil before and after modification were compared and analyzed.The regression equation of the compressive strength under the action of dry-wet and freeze-thaw cycles was established,and the drop hammer impact test of the foamed lightweight soil was carried out.The influence of the amount of latex powder on the impact performance of the foamed lightweight soil was obtained.(4)Using ABAQUS numerical simulation to compare the effects of different embankment heights,widening widths and bulk density of foam light soil on the settlement when conventional fill and foamed lightweight soil are used as subgrade fillers,the vertical settlement and settlement of the widened subgrade are obtained.The changing law of the horizontal displacement verifies the feasibility of using the foamed lightweight soil as the filler for widening the roadbed.