Research on Key Technologies of Subway Station Construction with PBA Method in Loess Strata
Construction of subway station with underground excavation method in loess strata is difficult and risky.Based on one subway station constructed by underground excavation method in Xi'an,this article introduces the design of subway station pilot tunnels using PBA approach,the reinforcement of lower guide tunnels,and the design scheme of PBA approach.And based on numerical simulation methods,the article compares and analyzes the surface settlement laws under different excavation sequences of pilot tunnels and lower pilot tunnels'reinforcement schemes.Some conclusions have been drawn.Firstly,the horizontal influence range is 1.5 times of the station span from the station center.Secondly,the surface settlement caused by pilot tunnels excavation and structure construction inside the pilot tunnels accounts for about 3/4 of the total settlement.Thirdly,for two pilot tunnels excavation sequences,the surface subsidence of top to bottom sequence is slightly smaller than that of bottom to top sequence.Finally,the reinforcement of the bottom of lower pilot tunnel has a small impact on the surface subsidence,but it is beneficial for controlling the bottom uplift.
万方数据
维普
