针对京沈客专望京隧道2号竖井施工中68 m深的地下连续墙在富含承压水且以粉细砂层为主的软弱地层中成槽难、垂直度控制难、42 m深的基坑安全与主体结构质量控制难等问题，提出对超深地下连续墙创新采用双拼工字钢接头柱、基坑上半部采用钢支撑替代混凝土支撑、基坑下半部环框梁与混凝土内支撑逆作、环框梁和腰梁合二为一、改进接头防水方式、改变竖井主体结构施工工艺等多项技术革新。得出主要结论如下： 1)在地下水丰富的软弱地层中，采用双拼工字钢接头柱可以显著提高超深地下连续墙的垂直度，减少接缝渗漏水现象； 2）通过优化超深竖井内部支撑体系和主体结构的施工顺序，并且将临时支撑结构和永久结构合二为一，可以显著加快施工进度、提高施工安全、节省施工成本。

Many problems, including complex groove creation, challenging management of verticality, and challenging safety and quality control of foundation pits, were encountered during the construction of the 68m deep No.2 shaft of Wangjing tunnel of BeijingShenyang passengerdedicated line. This tunnel is located in soft strata with fine sand layers that are predominately covered by rich confined water. This led to the adoption of a number of technical innovations for ultradeep diaphragm walls, including a double Ishaped steel joint column, steel support instead of concrete support in the upper half of the foundation pit, ring frame beam, and concrete internal support reversed in the bottom half of the foundation pit, a combination of ring frame beam and waist beam, improved joint waterproof, and modification of the shaft main structure construction technology. As a result, the following conclusions are drawn: (1) By using the double Ishaped steel joint column in the soft stratum with rich groundwater, the verticality of the ultradeep diaphragm wall can be considerably enhanced, and the water leakage of the joints can be decreased.  (2) By combining the temporary support structure and permanent structure and optimizing the internal support structure system and the main structure construction sequence of the ultradeep shaft, the construction process can advance more quickly, the safety can be increased, and the costs.