中文摘要：

根据莞惠城际轨道交通项目工程地质概况,以控制拱顶沉降、洞周变形、地表沉降和内力作为安全标准,通过现场试验段、室内模型试验和数值模拟计算的方法,研究城市浅埋隧道穿越饱和砂土复合地层时适宜的施工工法。研究结果表明：上CD下台阶五部施工工法为较适宜的工法;采用该工法时,洞室位移变化平稳,地表最大沉降不超过5mm,围岩—支护体系处于安全状态;该工法能将各工序紧密衔接,机械与人工配合形成流水作业,初支封闭时间缩短,有效加快施工进度,避免拱脚长时间处于淤泥质黏土、饱和砂土等软弱地层中,单导坑施工后形成封闭整体并取消了下台阶中隔壁,从而有效地控制了收敛和沉降;在城市浅埋隧道穿越含有饱和砂土的复合地层时,此工法可同时兼顾结构安全与周边协调。

英文摘要：

According to the engineering geological conditions of Dongguan-Huizhou intercity railway transport projects, with the control of vault settlement, deformation around the tunnel, surface settlement and internal force as safety standard, the suitable construction method for urban shallow tunnel crossing through complex stratum in saturated sandy soil was studied by field test section, laboratory model tests and numerical simulation. The results show that the five-part construction method of CD method above bench tunneling method is a more suitable construction method. This method makes the displacement of cavern change smoothly and the maximum ground settlement is less than 5 mm. Thus, the surrounding rock and support system is safe and reliable. This method can make a close connection between each working procedure. A flow process is formed by combining machinery with labor and the confining time for primary support is shortened. The construction progress is effectively sped up, which can avoid the arch foot situating in the soft ground of mucky clay and saturated sandy soil for a long time. After single pilot heading excavation, the closed body formed and median lamella under step is cancelled, so the convergence and settlement is effective controlled. When urban shallow tunnel crosses through the complex stratum in saturated sandy soil, this method can balance structure safety and harmony with surrounding conditions.