无水砂卵石地层土压盾构施工泡沫技术研究宋克志.pdfVIP

24 13 Vol.24 No.13 2005 7 Chinese Journal of Rock Mechanics and Engineering July 2005 12 3 3 2 2 (1. 264025 2. 100044 3. 100045) U 455.43 A 1000 6915(2005)13 2327 06 STUDY ON FOAM TECHNOLOGY DURING SHIELD EXCAVATION IN SANDY COBBLE BED WITHOUT WATER 12 3 3 2 2 SONG Ke-zhi WANG Bo KONG Heng YUAN Da-jun WANG Meng-shu (1. College of CommunicationsLudong Uiniversity Yantai264025 China 2. Research Center of Tunneling and Underground Works Beijing Jiaotong University Beijing100044China 3. Beijing Municipal Engineering Group Co. Ltd. Beijing100045China) Abstract The main types of shield machine used recently in tunnel construction are earth pressure balance(EPB) shield and slurry shield. In order to keep muck discharged fluently and lighten machine burdenthe soils in chamber of EPB shield should be plastic and fluid. This is fundamentally critical to ensure the shield to advance continuously and smoothly. Sandy cobble without water is a typically unstable stratum and its mechanical properties are unfavorable to force’s transitivity and spread. Sandy cobble is of unfavorable plasticity and fluidity which is sure to bring serious wear of cutter wheel and screw. Moreover earth pressure balance of face is not easily maintained and the face is easy to collapse. As a case of EPB shield constructiona sewage tunnel in Beijing is presented. In the beginning 200 m of the shield tunnelfield driving tests are carried out. Firstly mud is injected into the chamber to sustain the