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International Conference on Civil engineering and Transportation (ICCET 2011)

作者： Li, Yuanping Zhang, Wei Jinan Univ Key Lab Disaster Forecast & Control Engn Minist Educ Guangzhou 510632 Guangdong Peoples R China Jinan Univ Dept Mech & Civil Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ Joint Lab JiNan Univ Kazan Fed Univ Guangzhou 510632 Guangdong Peoples R China

ISBN: (纸本)9783037852422

The fractional dynamics equation of a viscoelastic two-member truss system, in which fractional derivative model introduced to simulate the materials' characteristics, is proposed. The simplified single DOF differential equation is developed combined with boundary conditions and symmetry. Dynamic behaviors of the fractional single DOF system with harmonic loads are discussed by numerical calculations. The results show that: the system may lead to chaotic motion via period-doubling bifurcations or intermittent routes;the dynamical character is greatly inflected by the varying of excitation amplitude or damping coefficient or fractional order.

关键词： Fractional derivative Viscoelasticity two-member truss Chaos

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Stability analysis of bank slope under conditions of reservoir impounding and rapid drawdown

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Journal of Rock Mechanics and Geotechnical engineering 2011年第S1期3卷 429-437页

作者： Xiaoping Chen Jingwu Huang College of Science and Engineering Jinan UniversityGuangzhou510632China Key Laboratory of Disaster Forecast and Control in Engineering Jinan UniversityGuangzhou510632China Guangdong Hydropower Planning and Design Institute Guangzhou510170China

Stability of an ancient landslide in a reservoir area is analyzed by using centrifugal model tests, soil laboratory tests and numerical analysis. Special attention is paid to variation in water level, simulation of large-scale heterogeneous prototype slope, and strength reduction of sliding zone soils after slope sliding. The results of centrifugal model test show that reservoir impounding can reduce sliding resistance at the slope toe, followed by toe collapsing and front cracking of slope. Rapid drawdown can produce hydrodynamic pressure towards reservoir at the front of slope. Deformation is observed in the middle and upper slope, which reduces the slope stability further and forms the pull-typed landslide trend. Reinforcement of slope toe is effective for preventing the progressive failure. The results of laboratory test show that slope toe sliding will lead to the redistribution of soil density and moisture content, which will reduce the shear strength of soil in sliding zone, and the cohesion of immersed soil is reduced gradually and finally vanishes with time. The numerical results show that the strength reduction method used in finite element method (FEM) is very effective in capturing the progressive failure induced by reservoir water level fluctuations, and the evolution of failure surface derived from numerical simulation is very similar to that observed in centrifugal model test.

关键词： slope stability reservoir impounding centrifugal model test strength reduction progressive failure

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Calculation of Normal Rock Breaking Force by Disc Cutter Based on Dimensional Analysis

Calculation of Normal Rock Breaking Force by Disc Cutter Bas...

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第四届国际机械工程与力学会议

作者： Qixing WU Xiangshang QI Hongwei MA Department of Mechanics and Civil Engineering Jinan University The Key Laboratory of Disaster Forecast and Control in Engineering Ministry of Education of ChinaJinan University College of Science & Engineering Jinan University

Based on the analysis of parameters used in the existing main calculation formulas of rock breaking force by disc cutter, by using dimensional analysis theory, a function has been developed among the normal rock breaking force by disc cutter and the parameters of Young's modulus of rock, uniaxial compressive strength of rock, cutter spacing and penetration of cutter. In combination with the measured data tested by linear cutting machine (LCM), by the method of multiple linear regression, the empirical regression formula of calculating normal rock breaking force by disc cutter is determined.

关键词： Dimensional Analysis, Disc Cutter, Normal Rock Breaking Force, Shield Machine

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Health Monitoring of in-service Bridge Deck by Covariance of Covariance Matrix of acceleration

Health Monitoring of in-service Bridge Deck by Covariance of...

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International Conference on Green Building, Materials and Civil engineering (GBMCE 2011)

作者： Li, Xueyan Law, S. S. Wang, Lixin Jinan Univ Minist Educ China Dept Mech & Civil Engn Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Hong Kong Polytech Univ Civil & Struct Engn Dept Hong Kong Peoples R China Earthquake Adm Guangdong Prov Guangzhou 510070 Peoples R China

ISBN: (纸本)9783037852033

A new matrix on the covariance of covariance is formed from the auto/cross-correlation function of acceleration responses of a structure under white noise ambient excitation. The components of the covariance matrix are proved to be function of the modal parameters (modal frequency, mode shape and modal damping) of the structure. The number of vibration modes associated with components of the matrix is only limited by the sampling frequency. Compared to the general methods for extracting modal parameters, the formulated covariance matrix contains more information on the vibration modes of the structure. An in-service suspension bridge is analyzed. Only the output acceleration responses are used to compute the covariance of covariance (CoC) matrix and the Pattern Assurance Criterion (PAC) values. From the CoCs variation and the changing trend of the PAC curve, the healthy condition of the bridge is assessed. The method is independent of analytical model and huge amount of data can be analyzed. It is especially suitable for long-term on-line health monitoring of a structure.

关键词： Health monitoring Damage detection System identification Ambient vibration Covariance of covariance correlation

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Application of Support Vector Machines in the prediction of broken zone in surrounding rock

Application of Support Vector Machines in the prediction of ...

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2011 International Conference on Remote Sensing, Environment and Transportation engineering, RSETE 2011

作者： Guo, Wei Jiang, Deyi Liu, Chun Key Lab. for the Exploitation of Southwestern Rsrc. and the Environ. Disaster Control Eng. Ministry of Education Chongqing University Chongqing China Safety Engineering College Chongqing University of Science and Technology Chongqing China

ISBN: (纸本)9781424491711

Introduce the principles of Support Vector Machines, and indicate the broken zone thickness can be forecasted by four factors: rock strength, joint coefficient, buried depth and span length. The results show that Support Vector Machine (SVM) is a reliable method to predict broken zone thickness, and the predictive values agree well with the verify data. © 2011 IEEE.

关键词： Support vector machines

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Simulation on dissolute and dust dispersion in comprehensive mechanized heading face with forced-exhaust ventilation

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Journal of Coal Science & engineering(China) 2011年第3期17卷 298-304页

作者： NIE Wen CHENG Wei-min HAN Li ZHOU Sheng-ju YU Yan-bin ZHAO Shan-shan Key Lab of Mine Disaster Prevention and Control Shandong University of Science and Technology Qingdao 266510 China New Julong Energy Resource Co. Ltd. Juye 274918 China Faculty of Safety Engineering China University of Minlng ＆ Technology Xuzhou 221008 China

According to the characteristics of comprehensive mechanized heading face, established the mathematical model of single-phase air flow with κ-ε two equations model, and have established κ-ε-θ-κp mathematic model to solve two-phase flow of gas and particles in dust space with eulerian-eulerian method and eulerian-lagrangian method. Numerical solution of gas-particle two-phase flow was put forward based on collocated grid SIMPLE algorithm. Moreover, numerical simulation of dust concentration in fully mechanized caving face was carded out by using Fluent software. Finally, when in forced-exhaust ventilation circumstance, drawer type fan drum have less dust absorption, and most of dust spread to the other site; the dust concentration is inversely proportional to the distance from tunneling head, and the dust concentration has already diffused to decrease below 102 mg/m3 at the position ofx=12 m. Dust are more focused on relative side（in the range about y from 0 to 2 meter） of roadway space of press-ventilated fan drum, especially between tunneling place and drawer type fan drum; the roadway with road header have a higher dust concentration. These conclusions provide reliable theory basis for the dust prevention in comprehensive mechanized heading face.

关键词： dissolute dust dispersion forced-exhaust ventilation circumstance κ-ε-θ-κp mathematical model comprehensive digging

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Peeling behavior and spalling resistance of CFRP sheets bonded to bent concrete surfaces

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Acta Mechanica Sinica 2010年第2期26卷 257-264页

作者： Hong Yuan Faping Li MOE Key Lab of Disaster Forecast and Control in Engineering Institute of Applied Mechanics Jinan University 510632 Guangzhou China

In this paper, the peeling behavior and the spalling resistance effect of carbon fiber reinforced polymer （CFRP） sheets externally bonded to bent concrete surfaces are firstly investigated experimentally. Twenty one curved specimens and seven plane specimens are studied in the paper, in which curved specimens with bonded CFRP sheets can simulate the concrete spalling in tunnel, culvert, arch bridge etc., whereas plane specimens with bonded CFRP sheets can simulate the concrete spalling in beam bridge, slab bridge and pedestrian bridge. Three kinds of curved specimens with different radii of curvature are chosen by referring to practical tunnel structures, and plane specimens are used for comparison with curved ones. A peeling load is applied on the FRP sheet by loading a circular steel tube placed into the central notch of beam to debond CFRP sheets from the bent concrete surface, meanwhile full-range load-deflection curves are recorded by a MTS 831.10 Elastomer Test System. Based on the experimental results, a theoretical analysis is also conducted for the specimens. Both theoretical and experimental results show that only two material parameters, the interfacial fracture energy of CFRP-concrete interface and the tensile stiffness of CFRP sheets, are needed for describing the interfacial spalling behavior. It is found that the radius of curvature has remarkable influence on peeling load-deflection curves. The test methods and test results given in the paper are helpful and available for reference to the designer of tunnel strengthening.

关键词： FRP sheet · Interfacial fracture energy ·Debonding · Spalling resistance · Bent concrete surface

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Adapting the usage of enzyme unit to its definition

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Journal of Chongqing University 2011年第1期10卷 23-25页

作者：杨明莉 Key Lab for the Exploitation of Southwestern Resources and the Environmental Disaster Control Engineering Ministry of EducationChongqing University College of Resources and Environmental Science Chongqing University

The enzyme unit U, by its definition, is the amount of enzyme that catalyses the transformation o f one micromole of substrate per minute under standard assay conditions. However, in practical use, it is identical with micromole or microgram per minute, which deviates from the essence of the definition as a measure of amount of substance. Such usage appears in many publications that involve enzyme kinetics and conveys obscure signification. In this article, we solved the confusion by regarding the unit U as a measure of amount of enzyme having a specified catalytic activity just like the basic SI unit mole （symbol tool） defined as the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of carbon 12. We introduced the concept of unit rate, ru, which is defined as the rate of a reaction mediated by 1 U enzyme, in calculating the enzyme units in an amount of enzyme so as to avoid the inconsistence of the expression with the definition of enzyme unit. The method can also be applied to the case of katal, the recommended SI unit of enzyme activity.

关键词： enzyme-catalyzed kinetics enzyme unit enzyme activity katal

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Quasi-Green’s function method for free vibration of simply-supported trapezoidal shallow spherical shell

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Applied Mathematics and Mechanics(English Edition) 2010年第5期31卷 635-642页

作者：李善倾袁鸿 Key Laboratory of Disaster Forecast and Control in Engineering Ministry of Education of China Institute of Applied Mechanics Jinan University

The idea of quasi-Green＇s function method is clarified by considering a free vibration problem of the simply-supported trapezoidal shallow spherical shell. A quasi- Green＇s function is established by using the fundamental solution and boundary equation of the problem. This function satisfies the homogeneous boundary condition of the prob- lem. The mode shape differential equations of the free vibration problem of a simply- supported trapezoidal shallow spherical shell are reduced to two simultaneous Fredholm integral equations of the second kind by the Green formula. There are multiple choices for the normalized boundary equation. Based on a chosen normalized boundary equa- tion, a new normalized boundary equation can be established such that the irregularity of the kernel of integral equations is overcome. Finally, natural frequency is obtained by the condition that there exists a nontrivial solution to the numerically discrete algebraic equations derived from the integral equations. Numerical results show high accuracy of the quasi-Green＇s function method.

关键词： Green function integral equation shallow spherical shell free vibration

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Study on Fractal-Like Dissociation Kinetic of Methane Hydrate and Environment Effect

Study on Fractal-Like Dissociation Kinetic of Methane Hydrat...

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The second International Conference of Electrical and Electronics engineering(ICEEE 2011)

作者： Xu Feng Wu Qiang Zhu Lihua Key Lab.for the Exploitation of Southwestern Resources & the Environmental Disaster Control Engineering Ministry of Education Chongqing University School of Safety Engineering & Technology Heilongjiang Institute of Science & Technology

By using observation method, the dissociation process of methane hydrate at normal temperature and pressure is studied, and it is discovered which the dissociation of methane hydrate isn't occurred synchronously at whole surface, but heterogeneous characteristic of dissociation is emerged. The dissociation rate of hydrate is slow at normal temperature and pressure, and average dissociation rate is 2.15×10-4m3·h-1. The dissociation kinetic equation of methane hydrate is proposed. It is revealed that the dissociation of methane hydrate at normal pressure is a pseudo first-order reaction. The dissociation rate coefficient of methane hydrate in different time is calculated, and the result shows that the rate coefficient is relative to reaction time, namely the dissociation kinetics of methane hydrate does not tally with the typical kinetics law, and the dissociation reaction kinetics of methane hydrate is fractal-like. Lastly, the environment effent of hydrate dissociation is also analyzed.

关键词： methane hydrate,dissociation,fractal-like,environment

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