Mechanical Properties Of Foamed Lightweight Soil And Its Application In Road Engineering

As a typical new lightweight material,foamed lightweight soil is widely used in various engineering fields due to its advantages of light weight,high strength,good fluidity and convenient construction,especially in the field of road engineering.However,the law of its mechanical properties affected by the storage environment is not clear,and the durability applied in engineering,deformation and stability under the influence of complex environment have become important problems restricting engineering safety.Based on the project of Kaili Ring Expressway in Guizhou Province,this paper studies the mechanical properties of lightweight foams with different proportions,the uncoordinated deformation,the long-term durability and the stability of subgrade slopes under rainfall.The main research contents are as follows:(1)The mechanical properties of light foam soil under complex environment.Based on laboratory tests,the dry mass,wet mass and strength of light weight soil with different proportions under cyclic drying and wetting cycles were studied.Under the freeze-thaw cycle,the strength changes with the number of cycles;The change law of its strength under the change of temperature.At the same time,the influence of the amount of fly ash and the ratio of water to binder on the properties of foamed lightweight soil was explored.(2)Study on deformation characteristics and long-term durability of lightweight foamed soil subgrade.Taking numerical simulation as the main means,the deformation characteristics of the roadbed before and after loading of different filling materials are studied.The effects of two parameters of foam lightweight soil bulk density grade and single pouring thickness on the deformation of foamed lightweight soil subgrade are considered.The influence of performance change of foam lightweight soil on long-term durability of subgrade engineering is studied.(3)The influence of rainfall on the stability of roadbed slope with lightweight foamed soil.Based on the actual engineering,the influence of the performance of the lightweight foamed soil subgrade on the long-term stability of the subgrade slope is studied,and the influence of rainfall intensity and rainfall type on the slope stability is also considered.The results show that:(1)Foam lightweight soil has better dry and wet resistance,freeze-thaw resistance and better temperature tolerance.Under the same test conditions,the increase of water binder ratio and fly ash will reduce the strength.(2)When foamed lightweight soil is used as roadbed filler,the roadbed deformation is the smallest.With the increase of light weight soil bulk density,the deformation of roadbed increases gradually,and the thickness of single foamed lightweight soil has little effect on the deformation of foamed lightweight soil subgrade.Based on the mechanical parameters of materials and the time varying regularity of related materials,it is shown that the long-term durability of foamed lightweight soil in subgrade engineering is better.(3)The influence of the performance of foamed lightweight soil roadbed on the long-term stability of subgrade slope is relatively small.The slopes under different rainfall intensity and rainfall types can meet the requirements of stability.