Study On Stability Of Retaining Structures In Saline Soil Regions Under Temperature Effects

With the continuous development of my country’s economy and technology,engineering construction is increasingly expanding to special land areas.Due to the particularity of its own soil,construction projects in saline soil areas will cause many problems,especially the complex interaction between the supporting structure and the fill and foundation during the construction process,making the construction more difficult.At present,the research on the supporting structure in general areas at home and abroad is relatively mature,but there are relatively few studies on the stability of the supporting structure in the saline soil area,which leads to great safety hazards in the supporting structure engineering in this area.With the continuous changes in temperature,the alternate cyclic action of earth pressure and salt expansion force is likely to cause damage to the supporting structure.This is the main reason why the supporting structure of the saline soil area is different from other areas.Therefore,it is necessary to study the temperature and salt expansion force behind the supporting structure in the saline soil area.This article takes a certain retaining wall project of the Chage Expressway as the research background,investigate and analyze the climatic characteristics and the distribution of saline soil along the route;By formulating indoor tests on the deformation and salt expansion force of saline soil at different temperatures and using the data obtained from the experiment,the stability of the retaining wall in this area was studied with FLAC3D numerical simulation software,mainly analyze from displacement cloud diagram and stress cloud diagram;Finally,the supporting structure is replaced and numerical simulation analysis is carried out,and the results of displacement and stress obtained from the previous supporting structure are compared,and the type of supporting structure suitable for the saline soil area is obtained.The main research contents are as follows:（1）Investigating the climatic characteristics and the distribution of saline soil along the Chage Expressway,it can be seen that chlorine saline soil is the main area along the line,and the climate in this area is arid,precipitation is scarce,and the temperature change generally conforms to a sine function curve.（2）The salt expansion force and deformation test of soil samples at different temperatures were developed,and the time history curve of stress and deformation at different temperatures from 20℃to-20℃（20℃、15℃、10℃、5℃、0℃、-5℃、-10℃、-15℃、-20℃）was obtained.The measured stress of the sample with a large SO₄^2-content is significantly higher than that of the sample with a small SO₄^2-content,and the measured deformation of the sample with a large SO₄^2-content shows a trend of first increasing and then decreasing and the samples with small SO₄^2-content showed a slow growth trend.（3）Using FLAC3D finite element numerical analysis software to simulate the temperature field distribution behind the retaining wall in different months of the year,it can be seen that the temperature distribution in different months is significantly different.as the depth increases,the temperature changes more and more slowly,and affected by external factors is getting smaller and smaller.（4）According to the data obtained from the experiment,FLAC3D was used to simulate the salt expansion force of the retaining wall,and the change law of the stress and deformation of the retaining wall in different months was obtained,so as to analyze the stability of the retaining wall.（5）Replace the supporting structure and conduct a numerical simulation of stability to compare with the previous results of stress and deformation of the retaining wall;combine the results of the analysis to determine the type of supporting structure suitable for the saline soil area,providing reference for similar projects in the future.