Research On The Mining Method Construction Technology Of Saturated Soft Loess Subway Tunnel

With the continuous development of urban rail transit in my country,saturated soft loess subway tunnels are gradually increasing.The problem of ground settlement caused by mining tunnel construction and its impact on adjacent buildings is particularly important.Based on the comprehensive analysis of engineering geology and stratum conditions,through theoretical analysis,on-site monitoring and finite element numerical simulation,this paper studies the surface settlement caused by the mining method of saturated soft yellow soil iron tunnel on the basis of comprehensive analysis of engineering geology and stratum conditions.And its impact on the surrounding buildings,put forward specific measures to control ground settlement under the background engineering conditions and a reasonable process of mining method construction.The main conclusions are as follows:(1)For the mine tunnel construction of saturated soft loess layer subway,precipitation treatment should be carried out first.After the precipitation,the saturated soft loess layer is dry and in good condition,and the engineering properties are improved,which is conducive to construction;(2)Saturated soft loess layer will produce large settlement after precipitation.The main in fluence range of settlement is about 20m around the precipitation well.In order to reduce the impact on the surrounding buildings,WSS full-section grouting construction process can be used to stop the water,improve the formation environment,and strengthen stratum;(3)When the saturated soft loess layer is large,the WSS full-section grouting construction process is adopted,and the reasonable grouting range is 2.5?3m outside the tunnel excavation contour.(The background thickness of this project is about 8.10?14.60m.Actual The grouting radius used in construction is 3m);(4)In order to control the impact of tunnel construction on adjacent buildings,isolation piles can be used.When differential settlement occurs in adjacent strata,the isolation piles can provide a certain amount of friction resistance to block the precipitation due to construction or the excavation of the tunnel soil.The displacement of the soil caused by the load reduces the differential settlement of the building;(5)When constructing a subway tunnel in a saturated soft loess layer,if there is no building near it,priority can be given to the method of precipitation to deal with the stratum.If there is a building near it,the construction technology of combining precipitation and grouting can be selected.Set up a dewatering well at the far end for precipitation to achieve a good grouting effect;...