Study On The Application Technology Of Lightweight Concrete In Steep Slope Subgrade Engineering Of High-Speed Railway

Steep slope embankment engineering is a key problem for high-speed railway subgrade engineering.The use of lightweight concrete can solve the problems finding in the high speed railway subgrade construction process and using which this new material is light,the intensity is adjustable,self-compacting,self-reliance.But so far little about lightweight concrete used in the high-speed railway roadbed of steep slope.In this paper,the study on the stability and mechanical properties of light concrete concrete is carried out by means of indoor experiment.Using ABAQUS finite element software,a hydrostatic model is used to analyze the steep slope of high speed railway.The main findings are as follows:1.The experimental research show that the water cement ratio,plastic density,casting height has influence on the stability of lightweight concrete construction.With the increase of water-cement ratio,the collapse height increases and the stability of lightweight concrete is reduced.When the water-cement ratio is less than 0.6,the stability change is not obvious.When the water-cement ratio is greater than 0.6,the collapse height increases and the stability decreases drastically.The higher the plastic density,the stratification phenomenon more obvious and the stability lower.This is more pronounced when the density is greater than 700kg/m~3 Therefore,when the light concrete as a high-speed railway steep roadbed filler,the density should be controlled at 700kg/m~3 or so.The height of pouring has a significant effect on the pouring body.The higher the height of the pouring,the greater the collapse and the stratification phenomenon more obvious.When the pouring height is below lm,the density of the pouring body is uniform.Through the analysis of the mechanical properties of lightweight concrete,when the density is greater than 500kg/m~3,the compressive strength can meet its use as roadbed packing,and the elastic modulus is much higher than the conventional AB and other soil packing.2.The finite element software static analysis results show that the use of lightweight concrete to fill the roadbed can significantly reduce the settlement value of the roadbed.The cross section of the steep slope of the lightweight concrete has a linear growth on the uphill side with a small filling height,and the settlement of the downhill side with larger thickness is smaller.The cross section of the steep slope roadbed with AB group packing concave non-linear growth.The lightweight concrete has good integrity,uniform vertical deformation,and the effect of reducing the settlement of the subgrade surface is obvious.Which reduces the influence of differential settlement of foundation on lateral subsidence of subgrade,and the calculation results of lightweight concrete with different density are not very different.The lateral pressure generated by the lightweight concrete subgrade on the retaining structure is much smaller than that of the conventional AB group.The maximum lateral displacement of the anti-slide pile is also obviously reduced,and the results of the light concrete with different density are not very diferent.The use of lightweight concrete can effectively reduce the settlement of the roadbed,better control the lateral defomation of the retaining structure,reduce the lateral difference of roadbed settlement,and the indicators meet the specification requirements.The results show that,when the lightweight concrete applicated in high-speed railway steep roadbed,the material density should be controlled at 700kg/m~3,pouring height control in 1m below the water-cement ratio of 0.6 or less,you can ensure the use of the results can also control costs,convenient construction.