| Recently,with the rapid development of the national economy,the demand for road transport has grown strongly.In the western region,the reconstruction and expansion of the original expressway has become the main way to solve the demand of transportation capacity.The Foamed lightweight soil has the advantages of light weight,vertical filling,environmental protection,etc.It has been widely applied in many fields,especially in solving the problem of bumping at bridge-head.The use of foamed lightweight soil in the high embankment filling and construction of the Liunan Expressway can saving land resource,eliminating slope and saving cost.At the same time,construction can be carried out without closing traffic,and normal travel will not be affected.This subject is based on the Liunan Expressway Reconstruction Project.The main research contents and conclusions are as follows:(1)This paper analyzes the existing problems of high-fill embankment,introduces the characteristics,application fields,and research status of the foamed lightweight soil,which is a new type of filling material,and introduces the research status of highway widening and reconstruction technologies at home and abroad.(2)Combined with the actual engineering requirements,the influence of Slag powder,fly ash,and bubble rate on the strength of foamed lightweight soil was investigated using orthogonal test methods.The experimental results show that the strength of the foamed lightweight soil decreases with the increase of the fly ash content and the bubble rate;with the increase of the mineral powder content,the strength increases first and then decreases.(3)A mix proportion that meets the requirements of the project has designed.In this mix ratio,one cubic Foamed lightweight soil material consists of 226 kg of cement,75.2 kg of slag powder,75.2 kg of fly ash,and a bubble rate of 62%.At the same time,for differentperiods,the method of controlling the quality and the corresponding technical inspection indicators were proposed which ensured the quality of the project.(4)The process of construction of foam lightweight embankment was monitored.To study the settlement and displacement of the foundation during the construction of the embankment.The monitoring data shows that during the construction process,the settlement and displacement rate of the foundation meet the requirements.With the increase of the embankment filling height,the foundation settlement increases and tends to be stable.(5)Using the finite element software Midas/GTS to simulate the high-fill embankment of foamed lightweight soil,Research in the stress characteristics and settlement deformation regular pattern under the new filling method.The result shows that during the process of filling foamed lightweight soil embankment,the difference in ground settlement will change with the increase of filling height,the additional stress at the foot of the embankment will be the largest,and the settlement will also be larger.Due to the increase of the local load,the compression settlement of the soil below the road shoulder causes some soil uplift outside the slope foot.The maximum horizontal displacement was 9 meters deep from the foundation.The stress distribution of the roadbed foundation was average and there is stress concentration at the foot of the slope. |
