Application Of Foamed Cement Banking In Highway Reconstruction And Extension Project

As a new type of roadbed filler,the strength of foamed cement banking can be adjusted freely.It has the characteristics of light weight,good fluidity and self-reliance after solidification.Used in highway expansion projects,it can greatly reduce the load and pour vertically.It can solve the difference of settlement between new and old roadbed,make up for the deficiency of conventional technology,and has good technical and economic effects.In this paper,combined with Haier Road reconstruction and extension project in Jiangbei,a series of studies on foamed cement banking are carried out by means of laboratory tests and numerical simulation.The main research contents and results are as follows:(1)Orthogonal test was used to study the influence of cementitious material content,fly ash content and water-cement ratio on the construction performance of light soil mixed with air bubbles.The results show that the effect of wet bulk density of light soil mixed with air bubbles is as follows:amount of cementitious material>water-cement ratio>amount of fly ash.The effect of fluidity of light soil mixed with air bubbles is as follows:water-cement ratio>fly ash content>cementitious material content.The effect of air bubble mixing on compressive strength of light soil is as follows:amount of cementitious material>amount of fly ash>water-cement ratio.The effect of wet bulk density increment of light soil mixed with air bubbles is as follows:amount of cementitious material>amount of fly ash>water-cement ratio.(2)Based on the regression analysis of raw material composition,wet bulk density and compressive strength,the influence of wet bulk density and compressive strength of light soil mixed with air bubbles was studied.With the help of regression model,the optimization method of raw material ratio of air bubble mixing light soil is put forward,and the mix ratio which meets the actual needs of engineering is obtained.(3)According to the design and construction requirements,ANSYS software is used to simulate and analyze the stress-strain changes and differential settlement of expanded Subgrade of air-bubble mixed light soil.The deformation(settlement)and stress variation of widened roadbed are obtained.The influence of material parameters on differential settlement of subgrade is analyzed.Among them,bulk density is the main factor affecting differential settlement.Elastic modulus has little effect on differential settlement,while Poisson’s ratio has little effect on differential settlement.Finally,the difference of settlement between widened embankment with air-bubble mixing light soil and widened embankment with common filling soil is compared and analyzed,and the improvement effect of air-bubble mixing light soil is further evaluated.