Numerical Analysis of Stress and Temperature Fields in a Composite Stratum Based on a New Method of Shield Construction for Safety and Environmental Protection
Abstract
:1. Introduction
2. Transformation of the Freezing Cutter Head
3. Freezing Control Model
3.1. The Law of Energy Conservation
3.2. Mathematical Model of the Freezing Temperature Field
4. Numerical Simulation
- (1)
- the initial ground temperature was determined according to the data obtained for the freezing project of a shallow tunnel, and the initial soil temperature before freezing was 18 °C;
- (2)
- the symmetrical surface of the geometric model was the adiabatic boundary, the cylindrical surface outside the soil layer was the constant temperature boundary, the interior of the freezing pipe was the convection heat exchange interface, the convection coefficient was set to 110 W/m2, and the coolant temperature was set to −30 °C.
5. Conclusions
- (1)
- Through numerical simulation, the change of the temperature field around the shield machine could be determined in real time. As time went on, the temperature around the cutter head decreased, and the freezing range expanded outwards. After a certain point in the temperature field reached a critical value, the temperature at that point remained constant, and the stress field of the cutter head also tended to stabilize.
- (2)
- In the case of uneven (1:1) soil, the isothermal region of the two types of soils presented a ring distribution due to the similar temperature transfer in the two types of soil.
- (3)
- With the distance from the freezing cutter head increasing, the final temperature of the soil gradually increased. The final temperature of the monitoring area was stable at −26.5 °C, the axial depth of the frozen wall was more than 5 m, and the minimum freezing radius was 3.2 m.
- (4)
- In the soft and hard uneven strata (1:1), the stress distribution around the cutter head was i unbalanced, the maximum stress (2.4 Mpa) was always measured in the hard soil layer, and the high stress around the cutter head at the hob position indicated that the cutter can be changed in this case.
- (5)
- Compared with the traditional method, the method of cutter head freezing of a shield machine here presented can better meet the safety and environmental protection requirements of underground construction.
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
- Zhang, Y.; Zhuo, X.; Guo, W.; Wang, X.; Zhao, Z. Lighting Environment Optimization of Highway Tunnel Entrance Based on Simulation Research. Int. J. Environ. Res. Public Health 2019, 16, 2195. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Wu, P.; Yang, F.; Zheng, J.; Wei, Y. Evaluating the Highway Tunnel Construction in Western Sichuan Plateau Considering Vocational Health and Environment. Int. J. Environ. Res. Public Health 2019, 16, 4671. [Google Scholar] [CrossRef] [PubMed] [Green Version]
- Lei, G. Troubleshooting of Common Construction Faults of Composite Shield Tunnel. Mod. Tunn. Technol. 2006, 43, 436–439. [Google Scholar]
- Qunfang, H.; Jiabao, Q. Statistical Analysis on Accidents of Subway Tunnel Construction from 2003 to 2011 in China. Chin. J. Undergr. Space Eng. 2013, 9, 705–710. [Google Scholar]
- Nilsen, B.; Dahl, F.; Holzhauser, J.; Raleigh, P. Abrasivity of Soils in TBM Tunnelling. Tunn. Tunn. Int. 2006, 38, 36–38. [Google Scholar]
- Nabendererde, S.; Hoek, E.; Marinos, P.; Cardoso, A.S. Geological Risk in the Use of TBMs in Heterogeneous Rock Masses—The Case of “Metro do Porto”and the Measures Adopted. In Geotechnical Risks in Rock Tunnels; Taylor & Francis: London, UK, 2006. [Google Scholar]
- Zhao, J.; Gong, Q.M.; Eisensten, Z. Tunnelling Through a Frequently Changing and Mixed Ground: A Case History in Singapore. Tunn. Undergr. Space Technol. 2007, 22, 388–400. [Google Scholar] [CrossRef]
- Chen, J.; Liu, H.; Min, F. Technical Review of Cutter replacement in Shield Tunneling. China J. Highw. Trans. 2018, 31, 36–46. [Google Scholar]
- Cao, L.; Zhang, D.; Fang, Q.; Hou, Y. Ground vertical displacements due to shield tunnelling in double-layer soil. Chin. J. Rock Mech. Eng. 2019, 38, 634–648. [Google Scholar]
- Si, J.; Zhu, Y.; Ji, C.; Zhou, S. Measurement and analysis of vertical deformation of stratum induced by quasi-rectangular shield tunneling in soft ground. Chin. J. Rock Mech. Eng. 2017, 36, 1551–1559. [Google Scholar]
- González, C.; Sagaseta, C. Patterns of soil deformations around tunnels: Application to the extension of Madrid Metro. Comput. Geotech. 2001, 28, 445–468. [Google Scholar] [CrossRef]
- Hu, X.; Guo, W.; Zhang, L.; Wang, J. Mathematical models of steady-state temperature fields produced by multi-piped freezing. J. Zhejiang Univ. Sci. A 2016, 17, 702–723. [Google Scholar] [CrossRef] [Green Version]
- Hu, X.; Hong, Z.; Fang, T. Analytical solution to steady-state temperature field with typical freezing tube layout employed in freeze-sealing pipe roof method. Tunn. Undergr. Technol. 2018, 79, 336–345. [Google Scholar] [CrossRef]
- Liu, J.; Ma, B.; Cheng, Y. Design of the Gongbei tunnel using a very large cross-section pipe-roof and soil freezingmethod. Tunn. Undergr. Space Technol. 2018, 72, 28–40. [Google Scholar] [CrossRef]
- Conrads, A.; Scheffer, M.; König, M.; Thewes, M. Robustness evaluation of cutting tool maintenance planning for soft ground tunneling projects. Undergr. Space 2018, 3, 72–85. [Google Scholar] [CrossRef]
- Frough, O.; Torabi, S.R. An application of rock engineering systems for estimating TBM downtimes. Eng. Geol. 2013, 157, 112–123. [Google Scholar] [CrossRef]
- Gallo, J.; Perez-Acebo, H. Performance model for Micro Tunnelling Boring Machines (MTBM). Inf. Constr. 2017, 69, e203. [Google Scholar] [CrossRef] [Green Version]
- Fan-lu, M.; Wei, Z.; Cheng, L.; Guo, X. Opening the Excavation Chamber of the Large-diameter Size Slurry Shield: A Case Study in Nanjing Yangtze River Tunnel in China. Tunn. Undergr. Space Technol. 2015, 46, 18–27. [Google Scholar]
- Xu, G.; Liu, Q.; Zhang, X. Theoretical analysis on full thermo-hydro-mechanical coupling for rocks under freezing temperature. Chin. J. Rock Mech. Eng. 2017, 42, 3709–3713. [Google Scholar]
- Hu, X.; Fang, T.; Han, Y. Generalized analytical solution to steady-state temperature field of double-circle-piped freezing. J. Chin. Coal Soc. 2004, 23, 3709–3713. [Google Scholar]
- Cheng, Z. Coupling of Temperature, Stress and Moisture Migration in Shallow Tunneling Using Multi-Freezing Pipes. Ph.D. Thesis, Central South University College of Geoscience and Environmental Engineering, Changsha, China, 2003; pp. 137–138. [Google Scholar]
Temperature (°C) | Coefficient of Thermal Expansion | Thermal Conductivity(W/m·°C) | Specific Heat (J/Kg·°C) | Density (kg/m3) | Modulus of Elasticity (Pa) | Poisson’s Ratio | Tensile Strength (kPa) |
---|---|---|---|---|---|---|---|
−30 | −9.6 × 10−5 | 6.3 | 810 | 1640 | 1.43 × 108 | 0.28 | 2.35 × 104 |
−28 | −9.6 × 10−5 | 6.3 | 810 | 1640 | 1.34 × 108 | 0.29 | 2.25 × 104 |
−26 | −9.5 × 10−5 | 6.3 | 810 | 1640 | 1.25 × 108 | 0.29 | 2.15 × 104 |
−24 | −9.4 × 10−5 | 6.3 | 810 | 1640 | 1.1 × 108 | 0.29 | 2.08 × 104 |
−22 | −9.4 × 10−5 | 6.3 | 810 | 1640 | 1.0 × 108 | 0.29 | 1.96 × 104 |
−20 | −9.3 × 10−5 | 6.3 | 810 | 1640 | 9.8 × 107 | 0.3 | 1.88 × 104 |
−18 | −9.3 × 10−5 | 6.3 | 810 | 1640 | 9.0 × 107 | 0.3 | 1.80 × 104 |
−16 | −9.2 × 10−5 | 6.3 | 810 | 1640 | 8.2 × 107 | 0.3 | 1.74 × 104 |
−14 | −9.2 × 10−5 | 6.3 | 810 | 1640 | 7.3 × 107 | 0.3 | 1.65 × 104 |
−12 | −9.1 × 10−5 | 6.3 | 810 | 1640 | 6.3 × 107 | 0.3 | 1.55 × 104 |
−10 | −9 × 10−5 | 6.3 | 810 | 1640 | 5.4 × 107 | 0.3 | 1.45 × 104 |
−8 | −8.8 × 10−5 | 6.3 | 810 | 1640 | 4.3 × 107 | 0.31 | 1.35 × 104 |
−6 | −8.5 × 10−5 | 6.3 | 810 | 1640 | 3.2 × 107 | 0.31 | 1.25 × 104 |
−4 | −8.5 × 10−5 | 6.3 | 810 | 1640 | 2.8 × 107 | 0.34 | 1.00 × 104 |
−2 | −8.4 × 10−5 | 6.3 | 810 | 1640 | 2.0 × 107 | 0.37 | 4.80 × 103 |
−1 | −6.6 × 10−5 | 5.25 | 34000 | 1710 | 1.5 × 107 | 0.39 | 3.50 × 103 |
0 | 0 | 4.2 | 880 | 1780 | 1.0 × 107 | 0.41 | 2.00 × 103 |
100 | 0 | 4.2 | 880 | 1780 | 1.0 × 107 | 0.41 | 2.00 × 103 |
Temperature (°C) | Coefficient of Thermal Expansion | Thermal Conductivity (W/m·°C) | Specific Heat (J/Kg·°C) | Density (kg/m3) | Modulus of Elasticity (Pa) | Poisson’s Ratio | Tensile Strength (kPa) |
---|---|---|---|---|---|---|---|
−30 | −5.5 × 10−5 | 6.3 | 810 | 1723 | 7.15 × 108 | 0.32 | 2.35 × 104 |
−28 | −5.4 × 10−5 | 6.3 | 810 | 1723 | 6.7 × 108 | 0.33 | 2.25 × 104 |
−26 | −5.4 × 10−5 | 6.3 | 810 | 1723 | 6.25 × 108 | 0.33 | 2.15 × 104 |
−24 | −5.3 × 10−5 | 6.3 | 810 | 1723 | 5.5 × 108 | 0.33 | 2.08 × 104 |
−22 | −5.2 × 10−5 | 6.3 | 810 | 1723 | 5.0 × 108 | 0.33 | 1.96 × 104 |
−20 | −5.2 × 10−5 | 6.3 | 810 | 1723 | 4.9 × 108 | 0.34 | 1.88 × 104 |
−18 | −5.1 × 10−5 | 6.3 | 810 | 1723 | 4.5 × 108 | 0.34 | 1.80 × 104 |
−16 | −5 × 10−5 | 6.3 | 810 | 1723 | 4.1 × 108 | 0.34 | 1.74 × 104 |
−14 | −4.8 × 10−5 | 6.3 | 810 | 1723 | 3.65 × 108 | 0.34 | 1.65 × 104 |
−12 | −4.8 × 10−5 | 6.3 | 810 | 1723 | 3.15 × 108 | 0.34 | 1.55 × 104 |
−10 | −4.7 × 10−5 | 6.3 | 810 | 1723 | 2.7 × 108 | 0.34 | 1.45 × 104 |
−8 | −4.5 × 10−5 | 6.3 | 810 | 1723 | 2.15 × 108 | 0.35 | 1.35 × 104 |
−6 | −4.4 × 10−5 | 6.3 | 810 | 1723 | 1.6 × 108 | 0.35 | 1.25 × 104 |
−4 | −4.3 × 10−5 | 6.3 | 810 | 1723 | 1.4 × 108 | 0.38 | 1.00 × 104 |
−2 | −4.1 × 10−5 | 6.3 | 810 | 1723 | 1.0 × 108 | 0.41 | 4.80 × 103 |
−1 | −3.5 × 10−5 | 5.25 | 34000 | 1796 | 7.5 × 107 | 0.43 | 3.50 × 103 |
0 | −2.1 × 10−5 | 4.2 | 880 | 1870 | 5.0 × 107 | 0.45 | 2.00 × 103 |
100 | 0 | 4.2 | 880 | 1870 | 5.0 × 107 | 0.45 | 2.00 × 103 |
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Dai, W.; Xia, Y.; Ning, B.; Yang, M. Numerical Analysis of Stress and Temperature Fields in a Composite Stratum Based on a New Method of Shield Construction for Safety and Environmental Protection. Int. J. Environ. Res. Public Health 2020, 17, 530. https://doi.org/10.3390/ijerph17020530
Dai W, Xia Y, Ning B, Yang M. Numerical Analysis of Stress and Temperature Fields in a Composite Stratum Based on a New Method of Shield Construction for Safety and Environmental Protection. International Journal of Environmental Research and Public Health. 2020; 17(2):530. https://doi.org/10.3390/ijerph17020530
Chicago/Turabian StyleDai, Wei, Yimin Xia, Bo Ning, and Mei Yang. 2020. "Numerical Analysis of Stress and Temperature Fields in a Composite Stratum Based on a New Method of Shield Construction for Safety and Environmental Protection" International Journal of Environmental Research and Public Health 17, no. 2: 530. https://doi.org/10.3390/ijerph17020530