黄土地区地铁车站洞桩法对地层的影响研究

Study on Influence of Hole-pile Method of Subway Station on Stratum in Loess Area

为研究黄土地区富水砂层地铁车站洞桩法对地表沉降及拱顶沉降的影响因素,依托西安市丰禾路地铁车站项目,对导洞的加固范围、开挖错距及开挖顺序进行数值模拟,结果显示:加固范围对该地区富水厚砂层地铁车站地表沉降及拱顶沉降影响较大,随着加固范围的增大,地层沉降逐渐减小;导洞开挖顺序对该地区地层沉降有一定影响,选择先边后中的开挖顺序产生的地表沉降及拱顶沉降更小;导洞的开挖错距对该地区地层沉降的影响不大,随着开挖错距的增大,地层沉降逐渐增大,但变化程度较小。根据结果进一步验证了该地区地铁车站洞桩法施工安排的合理性,即选择1.5m导洞加固范围,10m的开挖错距及先边后中的开挖顺序。

In order to study the influence factors of tunnel-pile method on surface settlement and vault settlement of metro station in water-rich sand layer in loess area,based on the Fenghe Road metro station project in Xi’an,the reinforcement range,excavation stagger distance and excavation sequence of pilot tunnel are numerically simulated.The results show that the reinforcement range has a great influence on the surface settlement and vault settlement of metro station in water-rich sand layer in this area.With the increase of reinforcement range,the stratum settlement gradually decreases.The excavation sequence of the pilot tunnel has a certain influence on the ground settlement in the area.The surface settlement and vault settlement caused by the excavation sequence of the first side and then the middle are smaller.The excavation offset of the pilot tunnel has little effect on the ground settlement in this area.With the increase of the excavation offset,the ground settlement gradually increases,but the degree of change is small.According to the results,the rationality of the construction arrangement of the tunnel pile method in the subway station in this area is further verified,that is,the reinforcement range of the 1.5m pilot tunnel is selected,the excavation staggered distance of 10m and the excavation sequence of the first side and then the middle.