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A Study on Impact of Soft Soil Stratum Reinforcement on the Attitude Regulation of Shield Machine and Stratum Deformation
(1. School of Civil and Traffic Engineering, Shenzhen University, Shenzhen 518060; 2. Key Laboratory of Coastal Urban Resilient Infrastructures (Shenzhen University), Ministry of Education, Shenzhen 518060; 3. Shenzhen Key Laboratory of Green, Efficient and Intelligent Construction of Underground Metro Station, Shenzhen 518060; 4. China Railway 15th Bureau Group Co., Ltd.,Shanghai 200070)
Abstract Based on the large-diameter shield tunnel project in soft soil strata in Hengqin District of Zhuhai City, this paper establishes a numerical simulation and analysis model for large-diameter shield tunnelling in unreinforced and pre-reinforced strata, and investigates the relationship between the deflection moment and pitch angle of the shield machine as well as the impact of the changes in the machine′s attitude on the deformation of the strata by changing the load distribution of the thrust system to apply the deflection moment. The results show that the gravitational eccentric moment that causes the initial "bow" of the shield machine is 261 MN·m, and the deflection moment required to level the attitude under the condition of pre-reinforced strata is about 21 MN·m, which is 81.1% smaller than the condition of un-reinforced strata (111 MN·m). Under the condition of pre-reinforced strata, for every 100 MN·m increase in the positive deflection moment, the pitch angle of the shield machine will increase by about 0.015°, which is 84.2% smaller than the condition of un-reinforcement (0.095°). Also, under the condition of identical negative deflection moment, the absolute value of pitch angle after pre-reinforcement is more than 85.0% smaller than the un-reinforced case. Pre-reinforcement of the strata results in a reduction of over 95.0% in both the maximum uplift and maximum settlement of the ground surface.
Abstract：
Based on the large-diameter shield tunnel project in soft soil strata in Hengqin District of Zhuhai City, this paper establishes a numerical simulation and analysis model for large-diameter shield tunnelling in unreinforced and pre-reinforced strata, and investigates the relationship between the deflection moment and pitch angle of the shield machine as well as the impact of the changes in the machine′s attitude on the deformation of the strata by changing the load distribution of the thrust system to apply the deflection moment. The results show that the gravitational eccentric moment that causes the initial "bow" of the shield machine is 261 MN·m, and the deflection moment required to level the attitude under the condition of pre-reinforced strata is about 21 MN·m, which is 81.1% smaller than the condition of un-reinforced strata (111 MN·m). Under the condition of pre-reinforced strata, for every 100 MN·m increase in the positive deflection moment, the pitch angle of the shield machine will increase by about 0.015°, which is 84.2% smaller than the condition of un-reinforcement (0.095°). Also, under the condition of identical negative deflection moment, the absolute value of pitch angle after pre-reinforcement is more than 85.0% smaller than the un-reinforced case. Pre-reinforcement of the strata results in a reduction of over 95.0% in both the maximum uplift and maximum settlement of the ground surface.
SU Dong1,
2,
3 TAN Yijun1 SHEN Xiang1 etc
.A Study on Impact of Soft Soil Stratum Reinforcement on the Attitude Regulation of Shield Machine and Stratum Deformation[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(2): 138-148
2023, Vol. 60 