Study On The Construction Technology Of Super-large Section Subway Station Excavated By Shallow Mining Method

According to research on a large number of relevant engineering projects, the paper hassummarized the main excavation methods, the key construction technologies and eachmethod’s advantages and their scope of application about super-large section subway stationexcavated by shallow mining method. After theoretical analysis, I have done a simulationstudy on the benching tunneling method by numerical simulation method. And demonstratethis excavation method’s feasibility and superiority by the standards which includesurrounding rock deformation, structural stress and the settlement of construction. Meanwhile,this paper has compared the results of simulation with the measured data. After analyzing thedata of different kinds of benching tunneling methods, the features of subsidence is given.According to the actual engineering situation, the reasonable range of parameters is present bystudying the optimization of some important construction parameters with the numericalsimulation method.The analysis shows that when the vault’s embedded depth less than1.0D, the settlementincreases with the increase of embedded depth; when the depth greater than1.0D, thesettlement decreases with the increase of embedded depth, while the reasonable range of thedepth is9.0-12.0m. Increasing the number of steps appropriately can improve the stability ofthe tunnel face, while the reasonable number of steps is4; Besides, improving thereinforcement range in a certain range can effectively reduce the surrounding rockdeformation and the construction settlement, but it is adverse to the surrounding rock stressand the settlement control when it is beyond the rang, while the reasonable reinforcementrange is2.0to3.0m. On the premise of guarantee the construction space, reducing the steplength is advantageous to the settlement control, while the reasonable step length is3.0to5.0m. Predicting and controlling the construction settlement about the super-large section subwaystation excavated should be based on the characteristics of construction settlement. In order toestablish a rigorous dynamic settlement control system, this paper has reach the rule of thesettlement of construction by numerical simulation method for prediction in advance aboutconstruction settlement, while assigning the total control values and warning values ofconstruction settlement to each excavation step. Doing this work, it can be controllingconstruction settlement and ensuring construction safety better. Meanwhile, it has a certainguiding significance for the similar projects.