Study On Application Of Foam Light Soil In Embankment Engineering

As a new type of filling material,foamed lightweight soil provides a new way to solve the settlement problem of soft soil foundation in coastal areas of China.In this paper,the Shangjung Interchange ramp project of Dehua Section of Xiamen-Shahejie Expressway is taken as the research carrier.Combination of theoretical analysis,experimental research and finite element numerical simulation,the following aspects are studied and relevant conclusions are drawn:(1)Combined with the actual engineering requirements,based on the relevant specifications,the preparation technology,raw materials utilization,mix proportion design and final production process of foamed lightweight soil are studied.A complete set of foam lightweight soil preparation scheme is also concluded based on laboratory tests.(2)The wet bulk density,fluidity,water absorption,shrinkage,flexural strength,unconfined compressive strength,modulus of elasticity and CBR properties of foamed light soil were studied by experiments.It was found that the wet bulk density,unconfined compressive strength,flexural strength and shrinkage rate of the lightweight foamed soil gradually increased with the decrease of the water solid ratio.The water absorption and fluidity of foam lightweight soil gradually decrease with the decrease of water solid ratio,and the functional relationship between unconfined compressive strength and flexural strength is obtained.And determine the best mix ratio suitable for the actual project in this paper is1m~3 foam light soil requires 430kg cement,258kg water,foam 30kg.(3)Detailed description of the actual engineering situation and the causes of the disease in this paper,and four solutions for foamed lightweight soil scheme,anti slide pile scheme,bridge plan and pile plate subgrade scheme are given.Through the comparison of construction technology and economic benefit,the best solution of foam lightweight soil is selected.(4)By establishing the corresponding solid model,the stress and displacement changes of roadbed under different filling materials,the light weight soil embankment with different bulk density,the light weight soil embankment with different elastic modulus and the different height of foamed lightweight soil under the filling height are studied by using the finite element software ABAQUS.The analysis shows that the final settlement of the foam light earth embankment is only 31%of the settlement of the ordinary fill embankment,The maximum vertical stress of the foundation is only 34%of that of the common fill.With the increase of bulk density of foamed lightweight soil and the increase of filling height,the settlement of foundation and the stress of foundation will also increase.The influence of elastic modulus of foam lightweight soil on subgrade settlement and basement stress is very small.