检索结果-南通市图书馆

Digital monitoring of rotary-percussive drilling with down-the-hole hammer for profiling weathered granitic ground

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1615-1636页

作者： Wendal Victor yue Siyuan Wu Manchao He Yafei Qiao zhongqi quentin yue Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai200092China Department of Civil Engineering Faculty of EngineeringThe University of Hong KongPokfulam RoadHong KongChina State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyBeijing100083China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai200092China

Rock and geotechnical engineering investigations involve drilling holes in ground with or without retrieving soil and rock samples to construct the subsurface ground profile.On the basis of an actual soil nailing drilling for a slope stability project in Hong Kong,this paper further develops the drilling process monitoring(DPM)method for digitally profiling the subsurface geomaterials of weathered granitic rocks using a compressed airflow driven percussive-rotary drilling machine with down-the-hole(DTH)hammer.Seven transducers are installed on the drilling machine and record the chuck displacement,DTH rotational speed,and five pressures from five compressed airflows in real-time series.The mechanism and operations of the drilling machine are elaborated in detail,which is essential for understanding and evaluating the drilling data.A MATLAB program is developed to automatically filter the recorded drilling data in time series and classify them into different drilling processes in sub-time series.These processes include penetration,push-in with or without rod,pull-back with or without rod,rod-tightening and rod-untightening.The drilling data are further reconstructed to plot the curve of drill-bit depth versus the net drilling time along each of the six drillholes.Each curve is found to contain multiple linear segments with a constant penetration rate,which implies a zone of homogenous geomaterial with different weathering grades.The effect from fluctuation of the applied pressures is evaluated quantitatively.Detailed analyses are presented for accurately assess and verify the underground profiling and strength in weathered granitic rock,which provided the basis of using DPM method to confidently assess drilling measurements to interpret the subsurface profile in real time.

关键词： Drilling process monitoring(DPM) Down-the-hole(DTH)hammer Percussive-rotary drilling Weathering granitic rocks

yue＇s solution of classical elasticity in n-layered solids： Part 2, mathematical verification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2015年第3期9卷 250-285页

作者： Zhong-qi quentin yue Department of Civil Engineering The University of Hong Kong Hong Kong China

This paper presents a detailed and rigorous mathematical verification of yue＇s approach, yue＇s treatment, yue＇s method and yue＇s solution in the companion paper for the classical theory of elasticity in n-layered solid. It involves three levels of the mathematical verifications, The first level is to show that yue＇s solution can be automatically and uniformly degenerated into these classical solutions in closed-form such as Kelvin＇s, Boussinesq＇s, Mindlin＇s and bi- material＇s solutions when the material properties and boundary conditions are the same. This mathematical verification also gives and serves a clear and concrete understanding on the mathematical properties and singularities of yue＇s solution in n-layered solids. The second level is to analytically and rigorously show the convergence and singularity of the solution and the satisfaction of the solution to the governing partial differential equations, the interface conditions, the external boundary conditions and the body force loading conditions. This verification also provides the easy and executable means and results for the solutions in n-layered or graded solids to be calculated with any controlled accuracy in association with classical numerical integration techniques. The third level is to demonstrate the applicability and suitability of yue＇s approach, yue＇s treatment, yue＇s method and yue＇s solution to uniformly and systematically derive and formulate exact and complete solutions for other boundary-value problems, mixed-boundary value problems, and initial-boundary value problems in layered solids in the frameworks of classical elasticity, boundary element methods, elastodynamics, Biot＇s theory of poroelasticity and thermoelasticity. All of such applications are substantiated by peer- reviewed journal publications made by the author and his collaborators over the past 30 years.

关键词： elasticity boundary element method elastodynamics poroelasticity thermoelasticity

fue＇s solution of classical elasticity in n-layered solids： Part 1, mathematical formulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2015年第3期9卷 215-249页

作者： Zhong-qi quentin yue Department of Civil Engineering The University of Hong Kong Hong Kong China

This paper presents the exact and complete fundamental singular solutions for the boundary value problem of a n-layered elastic solid of either transverse isotropy or isotropy subject to body force vector at the interior of the solid. The layer number n is an arbitrary nonnegative integer. The mathematical theory of linear elasticity is one of the most classical field theories in mechanics and physics. It was developed and established by many well-known scientists and mathematicians over 200years from 1638 to 1838. For more than 150years from 1838 to present, one of the remaining key tasks in classical elasticity has been the mathematical derivation and formulation of exact solutions for various boundary value problems of interesting in science and engineering. However, exact solutions and/or fundamental singular solutions in closed form are still very limited in literature. The boundary-value problems of classical elasticity in n-layered and graded solids are also one of the classical problems challenging many researchers. Since 1984, the author has analytically and rigorously examined the solutions of such classical problems using the classical mathematical tools such as Fourier integral transforms. In particular, he has derived the exact and complete fundamental singular solutions for elasticity of either isotropic or transversely isotropic layered solids subject to concentrated loadings. The solutions in n- layered or graded solids can be calculated with any controlled accuracy in association with classical numerical integration techniques. Findings of this solution formulation are further used in the companion paper for mathematical verification of the solutions and further applications for exact and complete solutions of other problems in elasticity, elastodynamics, poroelasticty and thermoelasticity. The mathematical formulations and solutions have been named by other researchers as yue＇s approach, yue＇s treatment, yue＇s method and yue＇s solution.

关键词： elasticity solution layered solid graded material

奠基岩石“封闭应力”假说的气体包裹体和膨胀能力

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

工程地质学报 2014年第4期22卷 739-756页

作者：岳中琦香港大学土木工程系

陈宗基先生在1979年提出了"封闭应力"假说,认为它是岩石工程灾害的原因。近年来,钱七虎院士和王思敬院士分别对"封闭应力"假说作了肯定的定性讨论。30多年过去了,这个"封闭应力"假说仅得到极其少的定量研究和发展。在本文中,我提出和试... 详细信息

陈宗基先生在1979年提出了"封闭应力"假说,认为它是岩石工程灾害的原因。近年来,钱七虎院士和王思敬院士分别对"封闭应力"假说作了肯定的定性讨论。30多年过去了,这个"封闭应力"假说仅得到极其少的定量研究和发展。在本文中,我提出和试图论证流体包裹体是一种具体、实在、可测量和计算的应力包裹体。它在地质岩石与矿物中普遍存在。它有压强和体积膨胀能。它是一种封闭应力和内应变能的具体存在和作用形式。我给出了这个压强、体积膨胀能和封闭应力包裹体对围岩作用的计算公式和算例。这个包裹流体压强值与深部岩石高地应力场值相当。我进一步分析和讨论了,岩石微小、密封、压紧的流体包裹体应该是深部工程岩石开挖洞室或巷道出现的岩爆、冲击地压、矿震、洞壁劈裂、围岩分区破裂和巷道大变形的一个共同张性体积力源。我认为,这个地质岩石与矿物内紧压膨胀的流体包裹体封闭应力能够完整逻辑一致地、符合自然规律地解释人们所见到的、报道的、与这些深部工程灾害相关的所有事实。并且,它能将这些事实和现象合理地、随时间演变地联系和重塑起来。这种实在、可测试、可定量的封闭应力源和能源的提出和研究能为岩石力学工作者,更好地沿着老一辈岩石力学专家们指引的途径和思路,来建立新的地质岩石力学理论、方法和技术,以更加符合自然规律地解决岩石力学领域世界性难题的深部工程灾害问题。

关键词：地质岩石力学封闭应力流体包裹体高地应力岩爆巷道大变形岩石工程

Local and teleconnected temperature effects of afforestation and vegetation greening in China

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

National Science Review 2020年第5期7卷 897-912页

作者： yue Li Shilong Piao Anping Chen Philippe Ciais Laurent Z.X.Li Sino-French Institute for Earth System Science College of Urban and Environmental Sciences Peking University Key Laboratory of Alpine Ecology and Biodiversity Institute of Tibetan Plateau Research Chinese Academy of Sciences Center for Excellence in Tibetan Earth Science Chinese Academy of Sciences Department of Biology Colorado State University Laboratoire des Sciences du Climat et de l'Environnement/Institut Pierre Simon Laplace Commissariata l Energie Atomique et aux Energies Alternatives–CNRS–Universite de Versailles Saint-QuentinUniversite Paris-Saclay Laboratoire de Met eorologie Dynamique Centre National de la Recherche ScientifiqueSorbonne UniversiteEcole Normale Superieure Ecole Polytechnique

Afforestation in China provides carbon sequestration and prevents soil erosion, but its remote impacts on climate in other regions via the coupling of forest energy fluxes with atmospheric circulation are largely unknown. Here, we prescribe inventory-based forest cover change and satellite-observed leaf area index from 1982 to 2011 in a coupled land-atmosphere model to simulate their biophysical climate effects. Both local and global surface air temperatures show a seasonal contrast in response to past vegetation cover expansion over China:a phenomenon we primarily attribute to a variation of seasonality of vegetation greening. A large cooling in spring results in concurrent decreases in geopotential height over China and zonal wind over Mongolia, causing a dipole structure in the upper troposphere over the Arctic. This accounts for～58%of simulated spring warming over the Russian Arctic and～61% of simulated spring cooling over the Canadian Artic. Our results imply that spring vegetation dynamics in China may affect climate in northern high latitudes.

关键词： afforestation vegetation greening China biophysical climate effect coupled land-atmosphere model