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Strengthening of the concrete face slabs of dams using sprayable strain-hardening fiber-reinforced cementitious composites

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Frontiers of Structural and Civil Engineering 2022年第2期16卷 145-160页

作者： Qinghua LI Xing YIN Botao HUANG Yifeng ZHANG Shilang XU Institute of Advanced Engineering Structures and Materials Zhejiang UniversityHangzhou 310058China

In this study,sprayable strain-hardening fiber-reinforced cementitious composites(FRCC)were applied to strengthen the concrete slabs in a concrete-face rockfill dam(CFRD)for the first ***,numerical,and analytical investigations were carried out to understand the flexural properties of FRCC-layered concrete *** was found that the FRCC layer improved the flexural performance of concrete slabs *** cracking and ultimate loads of a concrete slab with an 80 mm FRCC layer were 132%and 69%higher than those of the unstrengthened concrete slab,*** the maximum crack width of 0.2 mm,the deflection of the 80-mm FRCC strengthened concrete slab was 144%higher than that of the unstrengthened concrete *** addition,a FE model and a simplified analytical method were developed for the design and analysis of FRCC-layered concrete ***,the test result of FRCC leaching solution indicated that the quality of the water surrounding FRCC satisfied the standard for drinking *** findings of this study indicate that the sprayable strain-hardening FRCC has a good potential for strengthening hydraulic structures such as CFRDs.

关键词： strain-hardening cementitious composites engineered cementitious composites sprayable shotcrete strengthening concrete-face rockfill dam digital image correlation

Evaluation of the effect of using fiber reinforcement in tunnel linings for metro projects

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Underground Space 2021年第6期6卷 732-750页

作者： Mucahit Namli Department of Civil Engineering Istanbul Medeniyet UniversityUskudar/IstanbulTurkey

Metro(subway)is an advanced public transport infrastructure system in urban areas with high *** traffic operation of a metro is not affected by other vehicle traffic thanks to underground *** these benefits metro lines are preferred to solve the traffic problem in urbanized cities such as Istanbul,which is the focus of this *** projects require huge amounts of budgets to be *** these projects into service in targeted time is of great *** objective of this study is to minimize total metro construction project time by utilizing fiber reinforcement in tunnel *** this research,using fiber reinforcement to construct primary(initial)tunnel linings and secondary(final)tunnel linings of the metro projects are analyzed in terms of project *** comparison of two railway tunnel projects,evaluations and observations of a completed metro project revealed that using fiber reinforcement for either the primary lining or the final lining of tunnels reduces construction time of metro station tunnels by 25%.In addition,using fiber reinforcement to construct both the final lining and the primary lining of tunnels reduces construction time of the metro station tunnels and the whole metro project by 47% and 22%,*** results of this study can be useful for completing challenging metro projects and putting it into service within the targeted time.

关键词： Metro Tunnel Tunnel linings shotcrete Fiber Reinforced shotcrete Tunnel Boring Machines

Interpretation of tangential and radial pressure cells in and on sprayed concrete tunnel linings

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Underground Space 2021年第5期6卷 516-527页

作者： Benoit D.Jones Chris R.I.Clayton Inbye Engineering Limited Coventry CV12NPUK Department of Engineering University of SouthamptonSouthampton SO171BJUK

It is important to be able to measure stresses in tunnel linings to verify design assumptions and validate numerical *** sprayed concrete-lined tunnels,continuous monitoring of stresses from the time of spraying onwards is desirable,and this can only be achieved using pressure cells installed on and in the sprayed concrete *** there has been some success in using radial pressure cells between the ground and the lining,a method for obtaining reliable absolute values of stress from tangential pressure cells embedded in the sprayed concrete has not been *** paper describes numerical and experimental studies of the behavior of pressure cells for monitoring stresses in a sprayed concrete lining and describes an original methodology to achieve reliable *** particular,data from tangential pressure cells require careful interpretation,as they are sensitive to temperature,and this temperature sensitivity is found in parametric numerical analyses to vary as the stiffness of the concrete and its coefficient of thermal expansion evolve at early *** pressure cells are also sensitive to shrinkage strains in the concrete,and a methodology for removing this effect is *** the approach described in this paper,it is now possible to use pressure cells to measure absolute values of stresses in and on sprayed concrete tunnel linings from early age into the *** example of radial and tangential pressure cells installed in the Heathrow Terminal 4 concourse tunnel is used to illustrate the methodology.

关键词： Lining stresses Sprayed concrete shotcrete Monitoring Pressure cells

Principles and methods of rock support for rockburst control

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第1期13卷 46-59页

作者： Charlie Chunlin Li Norwegian University of Science and Technology(NTNU) TrondheimNorway

This paper presents the principles of rock support for rockburst control and three rockburst support systems used in deep metal *** the principles of rock support are presented,rock fracture related to strain burst is first discussed with the help of photos taken on site,and the energy sources and transformations during bursting are illustrated through conceptual *** parallel extension fracture usually occurs in the ejected and surrounding rocks in a strain burst event,while the ejected rock in a fault-slip rockburst is often already pre-fractured before the *** must be excessive release energy available for rock *** excessive release energy comes from both the ejected rock itself and the surrounding *** prevent rock ejection in a rockburst,the support system must be able to dissipate the excessive release *** support devices in a support system for rockburst control must be able to dissipate energy,be firmly linked,and be compatible in deformability.A support system for rockburst control comprises surface-retaining devices and yield rockbolts as well as yield cablebolts when *** mesh on the top of shotcrete liner is a good practice to enhance the surfaceretaining capacity of the support ***-absorbing yield rockbolts dissipate energy either by stretching of the bolt shank or by sliding of the inner anchor in the ***,mesh strap and shotcrete are the surface-retaining devices widely used in the current rock support *** three types of rock support used for rockburst control at present are soft support system using Split Set bolts,hybrid support system using rebar and two-point anchored yield bolts,and entirely yieldable support system using strong yield bolts.

关键词： Rock support Rockburst Rockbolt Yield rockbolt Mesh shotcrete

基于AMESim的喷浆机械手负载敏感技术的研究（英文）

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机床与液压 2015年第18期43卷 85-88页

作者：江守雷江守波马官国山东科技大学山东青岛266590

综述了喷浆机械手的工作原理,阐述了负载敏感技术的构成和工作原理,建立了负载敏感系统的AMESim模型,通过对系统的仿真研究,分析了负载敏感系统的压力及流量特性,为了解负载敏感系统的优点提供了数据支持,并为喷浆机械手的设计及发展提... 详细信息

综述了喷浆机械手的工作原理,阐述了负载敏感技术的构成和工作原理,建立了负载敏感系统的AMESim模型,通过对系统的仿真研究,分析了负载敏感系统的压力及流量特性,为了解负载敏感系统的优点提供了数据支持,并为喷浆机械手的设计及发展提供了理论依据。

关键词： shotcrete mechanical arm, Load sensing system, AMESim, Pressure characteristics, Flow character-istics

First-arrival traveltime tomography for monitoring the excavation damaged zone in the Horonobe Underground Research Laboratory

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Rock Mechanics Bulletin

Rock Mechanics Bulletin 2023年第3期2卷 32-43页

作者： Yusuke Ozaki Horonobe Underground Research Center Japan Atomic Energy AgencyHokushin 432-2Horonobe-choHokkaido098-3224Japan

Subsurface excavation results in the formation of a zone called excavation damaged zone(EDZ)around the tunnel *** EDZ is a major concern in the field of high-level radioactive waste disposal because it may act as a flow path after the closure of a *** this study,first-arrival traveltime tomography was repeatedly conducted on the EDZ at a depth of 350 m in the Horonobe Underground Research ***,the acquired data was highly affected by the support structure on the drift *** proper visualization of the EDZ,information about the structure was incorporated into the inversion by modifying the model *** synthetic study showed that the approach reproduced the EDZ in the model without the *** method was applied to field data,and the EDZ around the drift was *** inversion was extended to a time-lapse inversion to trace the changes in P-wave velocity in the *** synthetic study demonstrated that temporal changes in the P-wave velocity distribution could be *** obtained from 12 surveys under open-drift conditions were analyzed by time-lapse *** results indicated that the EDZ did not undergo sealing or evolution at the site for approximately seven years.

关键词： Excavation damaged zone First-arrival traveltime tomography Time-lapse inversion shotcrete

Rock Mass Characterization and Support Design for Underground Additional Surge Pool Cavern—A Case Study, India

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Geomaterials 2017年第2期7卷 64-82页

作者： Ajay Kumar Naithani Laishram Gopeshwor Singh Prasnna Jain National Institute of Rock Mechanics Bengaluru India

For better rock mass characterization and support design, 3D engineering geological mapping was carried for the heading portion of the under construction 200.00 m long, 68.75 m high and 20.20 m wide underground additional surge pool cavern of a Pranahitha-Chevella Sujala Sravanthi lift irrigation scheme package 8, India. To study cavern behavior, 3D geologic mapping of heading portion is very important for large cavern for predicting geologic conditions in benching down up to invert level, planning support system, selecting inclination for best location of supplemental rock bolt and choosing strategic locations for various types of instrumentation. The assessment of Tunnel Quality Index “Q” and Geomechanics classification for the granitic rock mass was done based on the information available of the rock joints and their nature and 3D geological logging. Hoek-Brown parameters were also determined by the statistical analysis of the results of a set of triaxial tests on core samples. On basis of geological characteristics and NMT Q-system chart, support system is recommended which includes rock bolt, steel fibre reinforced shotcrete and grouting. To evaluate the efficacy of the proposed support system, the capacity of support system is determined.

关键词： Engineering Geology Underground Cavern Support System Rock Bolt shotcrete

Use of Lightweight 3d Wire Panels to Construct Low Rise Structures in Seismic Areas： Some Applications and Design Rules

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Journal of Civil Engineering and Architecture 2010年第1期4卷 35-43页

作者： Waiei Mowrtage （Vail Karakale） Technical Education Faculty Kirklareli University Degirmencik Yolu Kirklareli Turkey

In high seismic regions of the world, including Turkey, there are too many low-rise residential buildings made of rigid masonry walls or flexible moment-resistant frames with brittle masonry partitioning walls. During even moderate earthquakes, these buildings suffer heavy damages and brittle failures causing hundreds if not thousands of people to lose their lives and homes. Hence it is essential to build a house with lightweight materials that have an earthquake resistance with a proper safety. Recently in some countries such as USA, Italy, China and Turkey; a new building system called 3D wire panel building system use prefabricated lightweight panels to construct low-rise buildings up to three stories. The panels are fabricated from polystyrene, steel, and shotcrete concrete .The lightweight of these panels, easy handling, high construction speed, good heat insulation properties, in addition to their low cost by avoiding formwork and need for skilled workers make it an acceptable construction practice. In the literature, there is no enough information on the design rules of this new building system .This paper presents some hits on the design rules and some applications in Turkey such as construction of a factory, construction of a three story villa and construction of mosque domes.

关键词： 3D panel shotcrete shear concrete.