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Numerical analysis of the influence of a river on tunnelling-induced ground deformation in soft soil

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第7期23卷 564-578页

作者： Jia-xin LIANG Xiao-wu TANG Tian-qi WANG Yu-hang YE Ying-jing LIU Research Center of Coastal and Urban Geotechnical Engineering Department of Civil EngineeringZhejiang UniversityHangzhou310058China Engineering Research Center of Urban Underground Space Development of Zhejiang Province Hangzhou310058China Zhongtian Construction Group Co. Ltd.Hangzhou310020China

When tunnels are constructed in coastal cities,they will inevitably undercross a *** the influence of rivers on tunnelling-induced deformation in costal soft soil is of great significance for controlling excessive settlement and protecting surrounding *** paper presents a case study of twin tunnels undercrossing a river in soft soil in Hangzhou,*** soft soil of Hangzhou refers to cohesive soil in a soft plastic or fluid plastic state with high natural water content,high compressibility,low bearing capacity,and low shear *** the influence of the river,the research region was divided into two parts,inside and outside the river-affected area,based on monitoring data of the Zizhi *** development law of surface settlement is divided into three *** the first and second stages,the surface settlement within and outside the river-affected area showed a similar trend:the settlement increased and the growth rate of settlement in the second stage was smaller within the river-affected *** the third stage,the surface settlement continued to increase within the river-affected area,while it converged outside the river-affected *** the river-affected area,there was an asynchronization of the sinking rate and stability of vault settlements and surface settlements.A numerical model was established by simulating different reinforcements of the *** numerical model revealed that the ground movement is influenced by the distribution and amount of the excess pore water *** excess pore pressure was concentrated mostly in the range of 1.0H_(t)-3.0H_(t)(H_(t) is the tunnel height)before the tunnel face,especially within the river-affected *** the river-affected area,the dissipation of excess pore water pressure needs more time,leading to slow stabilization of surface *** undercrossing a river,a cofferdam is necessary to reduce excessive ground deformation by dispersing the distribution o

关键词： tunnelling Ground deformation Numerical analysis Reinforcement

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Model of tunnelling through periodic array of quantum dots in a magnetic field

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Chinese Physics B 2012年第11期21卷 412-415页

作者： I.Yu.Popov S.A.Osipov St.Petersburg National Research University of Information Technologies Mechanics and OpticsKronverkskiy49St.Petersburg 197101Russia

A two-dimensional periodic array of quantum dots with two laterally coupled leads in a magnetic field is considered. The model of electron transport through the system based on the theory of self-adjoint extensions of symmetric operators is suggested. We obtain the formula for the transmission coefficient and investigate its dependence on the magnetic field.

关键词： tunnelling nanostructure operator extension theory

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Magnetic Quantum tunnelling in Faster Relaxation Process in Mn12Ac Molecular Magnets

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Chinese Physics Letters 2007年第2期24卷 532-535页

作者：刘海青苏少奎景秀年刘颖何伦华葛培文严启伟王云平 Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences PO Box 603 Beijing 100080

The field-tuned ac susceptibility of Mn12Ac single crystal has been measured as functions of temperature and frequency. Two relaxation processes appear in our measurement. One is related to the magnetic quantum tunnelling of a collective spin S = 12 by a 61 K magnetic barrier and it has been well studied, while the other is faster than the former and its mechanism is unclear. We find that the relaxation time for the faster process shows the minima at H = 0 and H = 3.4 kOe, indicating that the quantum tunnelling also takes place in this process while the resonant fields are different from what we have known before.

关键词： tunnelling Relaxation Molecular

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European legal framework related to underground mining and tunnelling concerning commission directive (EU) 2017/164, 31 January establishing a fourth list of indicative occupational exposure limit values

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International Journal of Mining Science and Technology 2020年第4期30卷 541-545页

作者： Miguel Tato Diogo Department of Mining Engineering Faculty of EngineeringUniversity of PortoPorto 4200-465Portugal

Directive(EU)2017/164 establishes a fourth list of indicative occupational exposure limit values(IOELVs)to protect workers from risks of exposure to hazardous *** states that in underground mining and tunnelling,Member States may benefit from a transitional period regarding IOELVs for nitrogen monoxide,nitrogen dioxide,and carbon monoxide,during which the existing established IOELVs may be *** European Advisory Committee on Health and Safety at Work questions the technical feasibility of the proposed IOELVs in underground mining(CO,NO and NO2)and tunnelling(NO and NO2).Challenges arise concerning the availability of measurement methodologies for compliance with proposed IOELVs(NO2)in underground mining and tunnelling environments.

关键词： Nitrogen monoxide Nitrogen dioxide Carbon monoxide IOELVs European Directive 2017/164 Underground mining tunnelling

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Assessment of strain bursting in deep tunnelling by using the finite-discrete element method

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 12-37页

作者： Ioannis Vazaios Mark S.Diederichs Nicholas Vlachopoulos Department of Ceological Saences and Ceological Engineering Queen's UniversityKingstonCanada

Rockbursting in deep tunnelling is a complex phenomenon posing significant challenges both at the design and construction stages of an underground excavation within hard rock masses and under high in situ stresses. While local experience, field monitoring, and informed data-rich analysis are some of the tools commonly used to manage the hazards and the associated risks, advanced numerical techniques based on discontinuum modelling have also shown potential in assisting in the assessment of rockbursting. In this study, the hybrid finite-discrete element method(FDEM) is employed to investigate the failure and fracturing processes, and the mechanisms of energy storage and rapid release resulting in bursting, as well as to assess its utility as part of the design process of underground *** the calibration of the numerical model to simulate a deep excavation in a hard, massive rock mass, discrete fracture network(DFN) geometries are integrated into the model in order to examine the impact of rock structure on rockbursting under high in situ stresses. The obtained analysis results not only highlight the importance of explicitly simulating pre-existing joints within the model, as they affect the mobilised failure mechanisms and the intensity of strain bursting phenomena, but also show how the employed joint network geometry, the field stress conditions, and their interaction influence the extent and depth of the excavation induced damage. Furthermore, a rigorous analysis of the mass and velocity of the ejected rock blocks and comparison of the obtained data with well-established semi-empirical approaches demonstrate the potential of the method to provide realistic estimates of the kinetic energy released during bursting for determining the energy support demand.

关键词： Rockburst Finite-discrete element method(FDEM) Deep tunnelling Hard rock excavations Brittle fracturing Discrete fracture network(DFN)

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A unified critical state model for geomaterials with an application to tunnelling

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第3期11卷 464-480页

作者： Hai-Sui Yu Pei-Zhi Zhuang Pin-Qiang Mo School of Civil Engineering University of LeedsLeedsLS2 9JTUK State Key Laboratory for GeoMechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221116JiangsuChina

This paper is prepared in honour of Professor *** for his outstanding contributions to rock mechanics and geotechnical engineering and also for his personal influence on the first author’s research career in geomechanics and geotechnical *** a result,we have picked a topic that reflects two key research areas in which Professor *** has made seminal contributions over a long and distinguished *** two areas are concerned with the application of the critical state concept to modelling geomaterials and the analysis of underground excavation or tunnelling in *** due to Professor Brown’s influence,the first author has also been conducting research in these two areas over many *** particular,this paper aims to describe briefly the development of a unified critical state model for geomaterials together with an application to cavity contraction problems and tunnelling in soils.

关键词： Critical state soil mechanics Constitutive models Cavity contraction tunnelling in soil

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Fermions tunnelling with Quantum Gravity Correction

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Communications in Theoretical Physics 2014年第12期61卷 819-823页

作者：柳振雨任继荣 Institute of Theoretic Physics Lanzhou University

Based on the generalized uncertainty principle(GUP), we investigate the correction of quantum gravity to Hawking radiation of black hole by utilizing the tunnelling method. The result tells us that the quantum gravity correction retards the evaporation of black hole. Using the corrected covariant Dirac equation in curved spacetime, we study the tunnelling process of fermions in Schwarzschild spacetime and obtain the corrected Hawking temperature. It turns out that the correction depends not only on the mass of black hole but also on the mass of emitted fermions. In our calculation, the quantum gravity correction slows down the increase of Hawking temperature during the radiation explicitly. This correction leads to the remnants of black hole and avoids the evaporation singularity.

关键词： black hole Hawking evaporation quantum tunnelling quantum gravity

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Feasibility study of tar sands conditioning for earth pressure balance tunnelling

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Journal of Rock Mechanics and Geotechnical Engineering 2015年第6期7卷 684-690页

作者： D.Martinelli D.Peila E.Campa DIATI-Politecnico di Torino Astaldi SpA

This paper presents the results of laboratory test on the feasibility of soil conditioning for earth pressurebalance （EPB） excavation in a tar sand, which is a natural material never studied in this respect. Thelaboratory test performed is based on a procedure and methods used in previous studies with differenttypes of soils, but for this special complex material, additional tests are also conducted to verify particularproperties of the tar sands, such as the tilt test and vane shear test usually used in cohesive materials, anda direct shear test. The laboratory test proves that the test procedure is applicable also to this type of soiland the conditioned material can be considered suitable for EPB excavations, although it is necessary touse a certain percentage of fine elements （filler） to create a material suitable to be mixed with foam. Thetest results show that the conditioned material fulfils the required standard for an EPB application.

关键词： tunnelling Earth pressure balance(EPB) Soil conditioning Tar sands Laboratory test

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High Efficiency SiC Terahertz Source in Mixed tunnelling Avalanche Transit Time Mode

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World Journal of Nano Science and Engineering 2014年第4期4卷 143-150页

作者： Pranati Panda Satya Narayana Padhi Gana Nath Dash Electron Devices Group School of Physics Sambalpur University Burla India

High frequency properties of 4H-SiC double drift region (DDR) Mixed tunnelling Avalanche Transit Time (MITATT) diodes are studied through computer simulation method. It is interesting to observe that the efficiency of SiC (flat) DDR MITATT diode (16%) is more than 4 times that of Si (flat) DDR MITATT diode (3.59%). In addition, a power output of more than 15 times from the SiC MITATT diode compared to the Si MITATT diode is commendable. A reduced noise measure of 17.71 dB from a low-high-low (lo-hi-lo) structure compared to that of 21.5 dB from a flat structure of SiC is indicative of the favourable effect of tunnelling current on the MITATT diode performance.

关键词： MITATT SiC Terahertz tunnelling

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Review of analytical methods for stress and deformation analysis of buried water pipes considering pipe-soil interaction

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Underground Space 2023年第6期13卷 205-227页

作者： Yingxu Huo Sherif Mohsen Mohamed Hassan Gomaa Tarek Zayed Mohamed Meguid Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHung HomHong Kong 999077China Department of Building and Real Estate The Hong Kong Polytechnic UniversityHung HomHong Kong 999077China Structural Engineering Department Faculty of EngineeringMansoura UniversityMansoura 35516Egypt Department of Civil Engineering McGill UniversityMontrealQuebec H3A 0G4Canada

Buried water pipelines are vulnerable to fail or break due to excessive loading or ground *** evaluation of pipe performance and serviceability relies on the proper understanding of pipe-soil interactions(PSI).Analytical methods are important approaches to studying ***,a systematic and thorough literature review to analyze the existing research trends,technological achievements and future research opportunities is not *** work investigates analytical methods that analyze the stress and deformation of pipes in terms of cross-sectional,transverse and longitudinal PSI ***,scientometric analysis is performed to acquire relevant research works from online databases and analyze the existing data of influential authors,productive research sources and frequent key word occurrence in the fields of ***,a qualitative discussion is performed in the three categories of PSI:(1)cross-sectional,including ovalization and circumferential behaviours;(2)transverse,including seismic fault crossing,weak soil zones,ground settlement and pipe uplift;and(3)***,six research opportunities are discussed,including the role of friction in cross-sectional deformation,combined effects of bending and compression,choice of soil reaction models and calibration of key parameters,effect of pipe flaws,soil spatial variability and behaviours of curved *** study helps beginners familiarize themselves with PSI analytical methods and provides experienced researchers with ideas for future research directions.

关键词： Pipeline Analytical methods Pipe-soil interactions Seismic fault Settlement Uplift Buckling tunnelling

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