Analysis Of Ground Settlement Caused By Shield Tunneling Method

The gradual acceleration of urban and rural integration has led to a surge in the population of major cities,and urban traffic is facing severe challenges.To solve the urban traffic pressure,the subway construction is imperative.Shield method is being more and more developed and applied in the subway construction because of its unique characteristics and advantages such as safety,intelligence and quickness,etc.But this method is inevitably caused ground surface settlement.This will affect the normal use and the safe running of the tunnel and the ground surface building while the ground surface settlement is too much.This paper refers the case project of the running tunnel from A station to B station in XIAN Metro,researches the ground surface settlement by using Shield method.In order to obtain the calculated curve,this paper summarizedthe theory of our predecessors and analyzed the ground surface settlement through the site-monitoring measurement data and calculated with MIDAS/GTS during the period of the construction.Combined with the geological condition,and construction value,etc.This paper analyzed the general discipline due to the construction with shield method and the factor that affects the size of the ground surface settlement.By optimizing the construction parameters and construction plan to proposing effective measures to control the ground surface settlement.This paper mainly draws the following conclusions:(1)Thicker top causing litter ground surface settlement.Under the same overburden thickness,the greater depth casing the greater the horizontal maximum settlement of the formation.(2)The vertical ground surface subsidence is greatly influenced by the driving pressure.Greater driving pressure casing litter ground surface settlement.(3)When the shield tail grouting is simulated by using equivalent circle zone,the elastic modulus of equivalent circle zone impacted on the vertical ground surface settlement little.Thicker equivalent circle zone causing greater ground surface settlement.(4)In double line tunnel constructing,the different excavation methods have no significant influence on the ground surface settlement.But,the method of left back right,Because of the settlement superposition effect,the settlement of the two tunnel center is different.