Recently, Associate Professor ZHANG Zhiguo, a young teacher of the School of Environment and Architecture received a notice from the editorial office of the Journal of Rock and Soil Mechanics. In view of the wide influence of a paper published in Chinese scientific journals and the large number of downloads and citations, it has been selected as a top academic paper library of F5000 in Chinese excellent journals (Outstanding 5000). The title of the selected paper is "Analytical solution for dissipation of excess pore water pressure and soil consolidation settlement induced by tunneling under the influence of long-term leakage". The paper was published in a journal Rock and Soil Mechanics which is honored as "China's Finest Science and Technology Journal", and "China's Most Influential International", and "China's Science and Technology Excellence Action Plan Selected Journal". All the authors of the papers were recommended to join the "Chinese Scientist Database" by the Institute of Scientific and Technical Information of China (ISTIC).
Nowadays, shield-driven tunneling has become widely used in urban cities to relieve the surface traffic congestion. The lining of a shield-driven tunnel is assembled by bolting together prefabricated concrete segments. The joints are very likely to open and to shear between segments when subjected to thrust jacking forces in the process of shield tunneling and permanent earth and pore pressure. Meanwhile, concrete cracks may be generated. Furthermore, the tunnel segments usually contain preformed holes for synchronous grouting during tunneling. In low-permeable clay, tunnel leakage will result in a continuous decrease in pore pressure around the tunnel and thereby induce ground and tunnel settlement. This leakage-induced tunnel settlement will deteriorate tunnel defects and threaten the safety of tunnel operation. It is of paramount significance for engineers to well understand the permeability of tunnel lining and soil properties in the analysis of tunnel leakage-induced ground consolidation subsidence in soft clay.
Fig.1 Influence of leakage of tunnel liner
This study introduces a new set of analytical solutions for predicting tunneling-induced dissipation of excess pore water pressure and surface consolidation settlements considering long-term leakage influence through a semi-permeable lining, based on the Terzaghi-Rendulic consolidation theory. The distribution of excess pore water pressure along circumference in the surrounding soil is estimated from closed-form solutions attained for the simplified cases in this work. The accuracy of the analytical presented solutions is verified by comparisons with observations of engineering profiles and good alignments are obtained. It is revealed from the analytical results that the tunnel leakage induces considerable surface consolidation settlements. Furthermore, the parametric analysis is performed on the influence of concerned coefficients on the surface consolidation settlement and the distribution of excess pore water pressure and it demonstrates that the soil-lining permeability ratio and the soil elastic modulus notably affects the tunnel leakage-induced ground responses.
Fig.2 Distribution of excess pore water pressure around tunnel
This study focus on the long-term surface responses induced by shield tunneling with a semi-permeable boundary imposed on the tunnel lining in saturated clay. Based on the Terzaghi’s two-dimensional consolidation theory, this work first converts a half-infinite plane consisting of a circle into a complex plane with a concentric circular region, resulting in the dissipation solution for the excess pore water pressure in the surrounding soil. Given the dissipation solution, the closed-form solution for the surface consolidation settlement controlled by time is instructively attained. The shield-driven tunnel with a perfectly sealed or impermeable and local leakage lining can be fully considered, such as, the leakage through joint seam, bolt holes, grouting holes and segment crack, and the long-term influence from the permeability of tunnel segment itself. The analytical algorithm can provide theoretical guidance for the risk control for construction of urban subway tunnel and the amendment of safety design specifications for shield lining structures.
Link to the paper "Analytical solution for dissipation of excess pore water pressure and soil consolidation settlement induced by tunneling under the influence of long-term leakage": 10.16285/j.rsm.2018.0913
The F5000 (Outstanding 5000) selection activity is led by the Ministry of Science and Technology in China, and is responsible for the selection by the authoritative scientific and technological information research institute-Institute of Scientific and Technical Information of China (ISTIC). It was officially launched in October 2012. The purpose is to promote the development of China's scientific and technological journals and to display and exchange excellent academic papers in China. The authors selected for F5000 will be recommended to John Wiley & Sons International Publishing Company as their journal reviewers or members of the journal editorial board. At the same time, the F5000 papers will enter Clarivate's Incites evaluation database system platform and become one part of Web of Science.
The selection method of the F5000 papers is based on the information of the "Chinese Science and Technology Papers and Citation Database", using a combination of quantitative analysis (5 years of citations) and qualitative analysis to scientifically evaluate the quality and influence of academic journals and select high-quality scientific journals. Each excellent journal chooses no more than 20 academic papers from the papers published in the past 5 years as F5000 selection papers. The selected papers are required to be the top 1% of highly cited papers in each subject, and are original scientific researches or technological innovations, which can reflect the highest academic level of the subject field for the journals.
A Brief Introduction of Dr. ZHANG Zhiguo
Zhiguo ZHANG is a Postdoctor, an Associate Professor and a Master Supervisor with more than 40 SCI and EI articles that have been published in the last five years. He has achieved and applied for more than 20 invention patents. He has supervised two items for National Natural Science Foundation of China - General Program, and one item for National Natural Science Foundation of China - Youth Science Fund. He has achieved the Shanghai Science and Technology Progress Award (First Level), and China Industry-University-Research Cooperation Innovation and Promotion Award (Second Level), and Zhejiang Society of Geotechnical Mechanics and Engineering-Science and Technology Progress Award (First Level). He is the Member of International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE), and the Director of Underwater Tunnel Engineering Technology Branch in Chinese Society of Rock Mechanics and Engineering, and the Member of Soft Soil Engineering Branch in Chinese Society of Civil Engineering, and the Member of Youth Committee for Soil Mechanics and Geotechnical Engineering Branch in Chinese Society of Civil Engineering. His research fields mainly include: (1) Tunnelling and underground structure engineering; (2) Deep excavation and foundation pit engineering; (3) Soil-structure interaction mechanics; (4) Pile and pipeline engineering.