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A land surface model incorporated with soil freeze/thaw and its application in GAME/Tibet

Science China Earth Sciences 2006年第12期49卷 1311-1322页

作者： HU Heping1, YE Baisheng2, ZHOU Yuhua3.& TIAN Fuqiang1 1. department of Hydraulic engineering, Tsinghua University, Beijing 100084, China 2. Cold and Arid Regions Environmental and engineering Research {3., Chinese Academy of Sciences, Lanzhou 73.000, China 3. department of civil engineering, massachusetts institute of technology, usa 1. department of Hydraulic engineering Tsinghua University Beijing 100084 China 2. Cold and Arid Regions Environmental and engineering Research institute Chinese Academy of Sciences Lanzhou 730000 China 3. department of civil engineering Massachusetts Institute of Technology USA

Land surface process is of great importance in global climate change, moisture and heat exchange in the interface of the earth and atmosphere, human impacts on the environment and eco- system, etc. Soil freeze/thaw plays an important role in cold land surface processes. In this work the diurnal freeze/thaw effects on energy partition in the context of GAME/Tibet are studied. A sophisti- cated land surface model is developed, the particular aspect of which is its physical consideration of soil freeze/thaw and vapor flux. The simultaneous water and heat transfer soil sub-model not only reflects the water flow from unfrozen zone to frozen fringe in freezing/thawing soil, but also demon- strates the change of moisture and temperature field induced by vapor flux from high temperature zone to low temperature zone, which makes the model applicable for various circumstances. The modified Picard numerical method is employed to help with the water balance and convergence of the numerical scheme. Finally, the model is applied to analyze the diurnal energy and water cycle char- acteristics over the Tibetan Plateau using the Game/Tibet datasets observed in May and July of 1998. Heat and energy transfer simulation shows that: (i) There exists a negative feedback mechanism between soil freeze/thaw and soil temperature/ground heat flux; (ii) during freezing period all three heat fluxes do not vary apparently, in spite of the fact that the negative soil temperature is higher than that not considering soil freeze; (iii) during thawing period, ground heat flux increases, and sensible heat flux decreases, but latent heat flux does not change much; and (iv) during freezing period, soil temperature decreases, though ground heat flux increases.

关键词： land surface model,soil freeze/thaw,GAME/Tibet,simultaneous liquid,vapor and heat transfer.

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TWO MODELS FOR ROLL WAVES IN A MUD LAYER

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Journal of Hydrodynamics 1995年第2期7卷 1-16页

作者： Chiang C. Mei Ko-fei Liu Chiu-on Ng(department of civil and Environmental engineering{3.,Cambridge,MA usa) massachusetts Inst of technology Cambridge United States

As has been extensively reported by hydraulic engineers in China, the flow of hyperconcentrated fluid mud in rivers is often pulsating and appears as roll waves. We report here two theories for such pulsating flows besed on two constitutive laws: the power law and Bingham plastic law. In order to account for the nonlinear bores convective inertia is kept in the approximate long wave equations. Kar man's momentum integral method with an assumed velocity profile is then employed. Results of the linearized instability analyses are *** bores are obtained either as stationary wave solutions or as the long- time limit of unstable disturbances which are initially infinitesimal. Implications on ho scour is examined.

关键词： hyperconcentrated fluid mud pulsating flow power law Bingham plastic Law

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DYNAMIC STABILITY AND DEFORMATION OF OFFSHORE GRAVITY PLATFORM FOUNDATION

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China Ocean engineering 1988年第1期2卷 31-42页

作者： Luan Maotian Jin Chongpan Doctor Candidate, civil engineering department, Dalian {3. of technology, Dalian Professor, civil engineering department, Dalian {3. of technology, Dalian Doctor Candidate Civil Eng Dept Dalian Inst of Tech Dalian PRC. China

t - The dynamic stability of the structure and deformation of marine foundation soils during storm condition or under seismic loading are of prime importance in designing offshore gravity structures. Based on limit equilibrium principle and pseudostatic concept, this paper develops a composite method for evaluating the dynamic stability of the structure foundation .subjected to such complicated loading. Moreover, computation procedures used to estimate stresses and deformations in the foundation under static and transient/eyclie loading are presented in detail. Finally, numerical results for a projected offshore gravity platform are given as examples.

关键词： DYNAMIC STABILITY AND DEFORMATION OF OFFSHORE GRAVITY PLATFORM FOUNDATION

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Numerical Simulation and Assessment of Self-induced Tensile Stresses in Steel Ring Restrained Concrete

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Journal of Wuhan University of technology(Materials Science) 2010年第3期25卷 530-533页

作者：马新伟 department of civil engineering Harbin Institute of Technology

For a better understanding of the strains and stresses,numerical simulation was conducted by using ANSYS under the assumption of absolute bond between the steel and *** results show that the stresses and strains in such concrete and steel rings are uneven;the curves of strains and stresses change gradually around the *** ease numerical computation,the mechanical system was simplified under the assumptions of synchronous deformation and uniform strains and *** results of the numerical simulation and simplified stress calculation can match almost *** means that the simplified mechanical model can be used in stress and visco-elastic behavior quantification.

关键词： restrained shrinkage numerical simulation model simplification

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Characteristics Research of Immersed and Waterlogged Subterranean River System of Reservoir Areas of Hydroelectric Stations

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Journal of China University of Geosciences 2003年第1期14卷 79-84页

作者： Li Wenxing department of civil engineering, Guilin {3. of technology, Guilin 54 1004 department of civil engineering Guilin Institute of Technology Guilin 541004

The karst immersion and waterlogging is one of the typical and the m os t harmful natural disasters in southern karst areas of China. It is threat to th e local production and life for a long time. In recent years, due to the constru ction of more reservoirs, the disaster became serious. This article takes immers ion and waterlogging of Banwen's subterranean rivers in Yantan reservoir area as an example, researches the daily rainfall's reflection to the water level of re servoir depression, discusses characteristics of immersion and waterlogging of t he valley, analyzes the disaster index in detail, such as water level process, t he highest water level, sensitive rainfall, original waterlogged rainfall and de layed day numbers etc., and provides the reference as a basis to the disaster an alysis.

关键词： reservoir areas of hydroelectric station subterranean river system immersed and waterlogged characteristic.

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Analytical and numerical modeling of resonant piezoelectric devices in China-A review

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Science China(Physics,Mechanics & Astronomy) 2008年第12期51卷 1775-1807页

作者： YANG JiaShi1,2↑ & YANG ZengTao1 1 institute of Mechanics and Sensing technology, School of civil {3. and Architecture, Central South University, Changsha 410083. China 2 department of {3. Mechanics, University of Nebraska, Lincoln, NE 68588-0526, usa 1. institute of Mechanics and Sensing technology School of Civil Engineering and Architecture Central South University Changsha 410083 China 2. department of engineering Mechanics University of Nebraska Lincoln NE 68588-0526 USA

The results on theoretical and numerical modeling of resonant piezoelectric devices in China are reviewed. Solutions to dynamic problems of the propagation of bulk acoustic waves (BAW), surface acoustic waves (SAW), vibrations of finite bodies, and analyses of specific devices are discussed. Results from both the ultrasonics community and mechanics researchers are included. It is hoped that the paper will be useful for the understanding, communication and collaboration between Chinese and foreign scholars. The paper may also be helpful for bridging the gap between ultrasonics and mechanics researchers on piezoelectricity re- search. The paper contains 3.6 references.

关键词： piezoelectricity wave vibration transducer resonator

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Internet-based collaborative pseudo-dynamic testing of multi-span bridge structure

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Progress in Natural Science:Materials International 2009年第5期19卷 623-633页

作者： Dapeng Wang a, Shizhu Tiana, Xinjiang Caia, Yunlei Fan b, Yan Xiaob,c a School of civil engineering, Harbin institute of {3., Harbin 150090, China b School of civil engineering, Hunan University, Changsha 410082, China c department of civil engineering, University of Southern California, Los Angeles, CA 90089, usa [a]School of civil engineering Harbin Institute of Technology Harbin 150090 China [b]School of Civil Engineering Hunan University Changsha 410082 China [c]Department of Civil Engineering University of Southern California Los Angeles CA 90089 USA

In this paper, the first Internet-based collaborative pseudo-dynamic testing of a multi-span bridge system in China’s mainland is presented in detail, which has been carried out by the collaboration of Hunan University (HNU), Harbin institute of technology (HIT) and Tsinghua University (TU) in China’s mainland, and the University of Southern California (USC) in the usa. The prototype system of Russion River Bridge at Southern California in America is illustrated. Different testing specimens, testing equipments and substructure boundary conditions at HNU and HIT laboratories are described. A network protocol platform for collaborative pseudo-dynamic testing, called NetSLab, and some function modules developed on the use of its standardized interface are introduced. Aiming at the MTS system widely used in structural testing, two approaches are presented to implement the communication interface between NetSLab and testing equipment, respectively, studied by HNU and HIT. The integrated networked testing system and collaborative testing procedures are presented. The testing results manifest that the networked collaborative testing system with powerful capability provides a testing platform with good coordination for complex models or actual structures, and achieves remote sharing of testing equipments.

关键词： Internet-based collaborative pseudo-dynamic testing Multi-span bridge structure Network protocol platform Communication interface Remote sharing of testing equipment

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Intelligent direct analysis of physical and mechanical parameters of tunnel surrounding rock based on adaptive immunity algorithm and BP neural network

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Journal of Pharmaceutical Analysis 2009年第1期21卷 22-30页

作者： Xiao-rui Wang1,2, Yuan-han Wang1, Xiao-feng Jia3..School of civil engineering and Mechanics,Huazhong University of Science and technology, Wuhan 43.074,China 2.{3. of civil engineering,Nanyang institute of technology,Nanyang 473.04,China 3.{3. of Chemistry and Bioengineering,Nanyang institute of technology,Nanyang 473.04,China. School of civil engineering and Mechanics Huazhong University of Science and Technology Wuhan 430074 China department of civil engineering Nanyang Institute of Technology Nanyang 473004 China department of Chemistry and Bioengineering Nanyang Institute of Technology Nanyang 473004 China

Because of complexity and non-predictability of the tunnel surrounding rock, the problem with the determination of the physical and mechanical parameters of the surrounding rock has become a main obstacle to theoretical research and numerical analysis in tunnel engineering. During design, it is a frequent practice, therefore, to give recommended values by analog based on experience. It is a key point in current research to make use of the displacement back analytic method to comparatively accurately determine the parameters of the surrounding rock whereas artificial intelligence possesses an exceptionally strong capability of identifying, expressing and coping with such complex non-linear relationships. The parameters can be verified by searching the optimal network structure, using back analysis on measured data to search optimal parameters and performing direct computation of the obtained results. In the current paper, the direct analysis is performed with the biological emulation system and the software of Fast Lagrangian Analysis of Continua (FLAC3.. The high non-linearity, network reasoning and coupling ability of the neural network are employed. The output vector required of the training of the neural network is obtained with the numerical analysis software. And the overall space search is conducted by employing the Adaptive Immunity Algorithm. As a result, we are able to avoid the shortcoming that multiple parameters and optimized parameters are easy to fall into a local extremum. At the same time, the computing speed and efficiency are increased as well. Further, in the paper satisfactory conclusions are arrived at through the intelligent direct-back analysis on the monitored and measured data at the Erdaoya tunneling project. The results show that the physical and mechanical parameters obtained by the intelligent direct-back analysis proposed in the current paper have effectively improved the recommended values in the original prospecting data. This is of p

关键词： adaptive immunity algorithm BP neural network physical and mechanical parameters surrounding rock direct-back analysis

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Experimental Study on the Effect of Cyclic Preloading on the Resistance to Liquefaction of Saturated Loose Sand under Wave Loading

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Journal of Shanghai Jiaotong university(Science) 2009年第4期14卷 398-403页

作者：张振东栾茂田金丹郭莹聂影 State Key Laboratory of Coastal and Offshore engineering Dalian University of Technology institute of Geotechnical engineering School of Civil and Hydraulic EngineeringDalian University of Technology department of civil engineering Huaihai Institute of Technology

By using the soil static and dynamic universal triaxial and torsional shear apparatus, a series of combined cyclic shear tests are performed to simulate the rotation in the principal stress direction induced by ocean wave. The tests include the cyclic preloading tests and liquefaction tests in the second loading on saturated loose sand with a relative density of 3.%. The all tests are consolidated under isotropic condition. The effect of the cyclic preloading on the resistance to liquefaction of saturated loose sands under the condition of continuous rotation in the principal stress direction is investigated. Experimental data indicate that the void ratio of saturated sands has a negligible reduction after cyclic preloading. With the increase of the intensity of cyclic preloading (in the amplitude and in the number of cycles), the resistance to liquefaction in the second loading is increased continuously under the condition that the liquefaction does not occur during the cyclic preloading. The reason is that the construction of more stable structure due to the uniformity of the void and the better interlocking of the particles when the cyclic preloading is applied to the saturated sand.

关键词： saturated sand liquefaction continuous rotation in the principal stress direction cyclic preloading second loading void ratio

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THE TRANSFORMED NONPARAMETRIC FLOOD FREQUENCY ANALYSIS

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Journal of Computational Mathematics 1994年第4期12卷 330-338页

作者： Kaz Adamowski(department of civil engineering University of Ottawa, Ottawa, Canada)Wojciech Feluch({3. of Environmental engineering , Technical University of Warsaw, Warsaw, Poland) UNIV OTTAWA DEPT CIVIL ENGNOTTAWA K1N 6N5ONTARIOCANADA WARSAW UNIV TECHNOL INST ENVIRONM ENGNPL-00661 WARSAWPOLAND

The nonparametric kernel estimation of probability density function (PDF) pro-vides a uniform and accurate estimate of flood frequency-magnitude ***, the kernel estimate has the disadvantage that the smoothing factor h is estimate empirically and is not locally adjusted, thus possibly resulting in deteri oration of density estimate when PDF is not smooth and is heavy-tailed. Such a problem can be alleviate by estimating the density of a transformed random vari able, and then taking the inverse transform. A new and efficient circular transform is proposed and investigated in this paper

关键词： TRT Res THE TRANSFORMED NONPARAMETRIC FLOOD FREQUENCY ANALYSIS

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