浅覆土盾构穿越潮汐河流地层变形规律

当前中国城市轨道交通发展迅速，地铁开挖下穿越潮汐河流面临诸多风险。为研究浅覆土盾构穿越潮汐河流的地层变形规律，以青岛地铁四号线盾构法穿越某浅覆土潮汐河流为依托，重点考虑河流的潮汐变化，结合工程中采用的注浆压力、工作面压力等施工参数，运用数值模拟的手段建立了更加符合实际情况的起伏地层，进而对地层变形规律开展研究。研究发现河底地层变形与河道水位深度呈正相关；涨潮和退潮时的地层横向沉降曲线形状存在差异且最大沉降量相差达50%;隧道掘进在时间效应上的地表沉降可分为4个阶段，需加强对中期盾构开挖及加固阶段的监测频率。

Formation Deformation of Tidal River by Shield Tunneling under Shallow Overburden

At present, urban rail transit in China is developing rapidly, and there are many risks in crossing tidal rivers under subway excavation. In order to study the stratum deformation law of shallow overburden shield crossing tidal river, based on the shield method of Qingdao Metro Line 4 crossing a shallow overburden tidal river, the research considers the tidal variation of the river, in combination with the engineering use the construction parameters such as grouting pressure, face pressure. A more realistic undulating stratum is established by means of numerical simulation, and then the deformation law of stratum is studied. It is found that there is a positive correlation between river bed deformation and river water level depth. The shape of lateral settlement curve is different between rising tide and ebb tide and the difference of maximum settlement is 50%. The time effect of tunnel excavation on surface settlement can be divided into four stages. The monitoring frequency of shield excavation and reinforcement should be strengthened.