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- Title
Load Pattern on Tunnel Lining in Jet Grouting Reinforced Mud Stratum.
- Authors
LIU Hua; LIU Zhi; ZHANG Wenlong; HU Yazhou; LIU Renpu; TAN Qianyuan; XIE Nan; JIANG Haibo
- Abstract
Jet grouting reinforcement is a commonly used ground improvement technique during shield tunneling in the soft stratum. So far, the load distribution characteristics of lining in the kind of stratum are still unclear. In this study, field measurements are carried out based on the subway project between Guiwan and Qianwan stations of the Shenzhen Metro Line 5. The earth pressures on three test sections are measured, and the time histories and spatial distributions of the earth pressure are analyzed. The measured earth pressure is compared to the design value, and the influence of the coefficient of soil reaction is discussed. The results indicate that the earth pressure experiences three stages after lining assembly: increases rapidly and reaches a peak under the temporary construction loads such as grouting pressure, drops in a fluctuating manner, changes slowly and gradually tend to stabilize; the jet-grouted piles hinder the dissipation of grout and cause the lining segment near the backfill grouting holes bearing greater radial pressure in the long term, which even reaches 1.76 times the mean value of the earth pressure on lining; the vertical jet-grouted piles raise certain load transfer and leads to the earth pressure on the lining being significantly smaller than the full overburden pressure, the existence of the load transfer shows a degree of randomness; the measured earth pressures is closer to the design value without considering horizontal soil reaction. Based on the above results, some suggestions for the design and construction of the shield tunnel in the kind of stratum are proposed: reasonably adopting lower grouting amounts and more grouting holes along the lining ring; when the ratio of burial depths to outer diameters below 1.45, the full overburden pressure should be used as the external load of tunnel lining for design.
- Publication
Railway Standard Design, 2023, Vol 67, Issue 12, p143
- ISSN
1004-2954
- Publication type
Article
- DOI
10.13238/j.issn.1004-2954.202206090001