Research on Key Technology of Integral Translation and Rotation of the Large-Diameter Shield and Steel Sleeve in the Underwater Tunnel of the Karnaphuli River, Bangladesh

Abstract

The construction of the underwater tunnel of the Karnaphuli River in Bangladesh boasts the characteristics such as short time limit, small working shaft space and a large weight of the shield tunneling machine and etc.. Moreover, the translation and rotation of the shield tunneling machine are the key link of the entire construction, which also takes a longer time and is more difficult to achieve. The existing rotating technology of a shield tunneling machine and its applicable conditions were analyzed to conquer the difficulties like the tight time limit and the high mechanical level of disassembling and assembling of the shield tunneling machine in this project. The technology of integral translation and rotation of the large-diameter steel sleeve of the shield and the shield tunneling machine was proposed according to its characteristics and the present situation of confined working space. The technology mainly includes the design and application of the new steel ball base, the preparation of the working shaft space and its base, the leveling and translation of the shield tunneling machine, the translation of the shield machine, and its rotation at 180° in situ. The sliding friction between the sleeve base and the bottom plate of the working shaft is turned into rolling friction by the new steel ball base, which can effectively reduce the resistance of the translation and rotation of the steel sleeve. In a word, the working efficiency can be highly improved and the construction period can be shortened.