超大型箱涵顶进引起的地层位移规律研究

郑州市下穿北京―珠海高速公路立交工程是目前亚洲在软土地层中施工的横截面最大的管棚内箱涵顶进工程，如何控制地层位移以及保证公路的安全，是设计和施工中必须考虑的主要问题。对现场的实测数据进行了分析，并应用FLAC数值方法对顶进过程中引起的地层位移进行模拟计算。现场监测和数值模拟结果对比表明，两者基本接近。总结出的地层移动规律如下：①路面发生最大沉降的位置不在轴线处，而是在箱涵跨度的一半处；②最大的水平位移出现在与箱涵中心同一标高掌子面正前方的土体中。管棚复合体的水平位移与路面大致相当，基底的水平位移略小。③孔隙水压力对箱涵顶进引起的周围土层的扰动更为灵敏。

Research on soil displacement regulations with jacking method for super-large shallow-buried box culvert

The super-large shallow-buried box culvert with jacking method and pipe-roof crossing Beijing-Zhuhai Expressway in Zhengzhou is the largest in soft soil in Asia. How to control the soil displacement and protect the expressway are the main problems considered in design and construction. With in-situ data, FLAC is employed to study the soil displacement during the construction process. By analyzing the measured results and numerical stimulation results, the soil displacement regulations are given as follows: ① The biggest settlement point of the pavement is not on the axis, and the distance between the point and the axis is about half span of box culvert. ② The biggest horizontal movement is in the soil in front of excavating face with the same elevation of the box culvert axis. The horizontal movements of pipe roof composites are roughly equal to that of the pavement. ③ The pore water pressure is more sensitive to the disturbing of soils in the process of box culvert jacking.