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作者： Ye, Siqiao Li, Ke Chen, Hongkai Key Lab. for the Exploitation of Southwestern Resources Environmental Disaster Control Engineering Ministry of Education Chongqing China Institute of Geotechnical Engineering Chongqing Jiaotong University Chongqing China

ISBN: (纸本)9781457702907

The impact force by rockfall events is the main loads for structure design such as tunnel entrances and rockfall passive mitigation mearsures. But the impact force formula are empirical or theoretical calculation methods in the case of positive impact. To solve the impact force calculation problem in case of olique impact, by systematicly comparative analysis between numerical simulation and formula calculation method in case of different impacting speed, different buffer layer thickness and different rockfall size, the authors found that numerical analysis and formula calculated results changed in the same way. And the numerical differences are within 10%. It si proved that by speed decomposition, extending the positive impact force calculation mehtod to the the oblique collision is feasible. But also for calculation of rockfall impact force beyond the scope of the formula, numerical simulation is a feasible way. © 2011 IEEE.

关键词： Numerical methods

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Perturbation Analysis of Instability for Non-uniform Cylindrical Shells with Initial Imperfection

Perturbation Analysis of Instability for Non-uniform Cylindr...

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2011 China control and Decision Conference(2011中国控制与决策会议 CCDC)

作者： Jianghong Xue Department of Mechanics and Civil Engineering Jinan University / Key Lab of Disaster Forecast and Control in Engineering Ministry of Education Guangzhou 510632

Buckle propagation in subsea corroded pipelines is one of the most concerned problems in offshore industries, while locating the plastic hinges in the corroded pipeline is the crux in determining the buckle propagation pressure. This paper presents a methodology to determine the locations of plastic hinges in non-uniform shells subjected to external pressure. The non-uniform shell used to model the corroded pipeline has two Regions: Region 1 of reduced, inconstant thickness and Region 2 of nominal thickness. Analytical formulas for the bifurcation load, radial deformation, initial yield pressure and stress distribution in the non-uniform shell are derived from perturbation analysis using WKB expansion. The locations of plastic hinges are identified at the stress peaks by taking the derivative of the stress with respect to circumferential coordinate. Imperfection sensitivity of the non-uniform shell is assessed with an emphasis on the role of initial yield pressure and the locations of plastic hinges. Special case when the thickness of Region 2 is constantly reduced is examined. It is found that both the initial yield pressure and the locations of plastic hinges depend on the non-uniform conditions of the cylindrical shell.

关键词： Perturbation Analysis Location of Plastic Hinge Corroded Pipeline Buckle Propagation

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Volume shrinkage risk analysis of salt rock cavern gas storage based on reliability method

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Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and engineering 2012年第SUPPL. 2期31卷 3673-3680页

作者： Jing, Wenjun Cheng, Lin Yang, Chunhe Xu, Yulong Zhang, Yujun Shi, Xilin State Key of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan Hubei 430071 China Petro China West East Gas Pipeline Company Shanghai 200122 China Key Lab. for Exploitation of Southwestern Resources and Environmental Disaster Control Engineering Ministry of Education Chongqing University Chongqing 400044 China

Effective volume reduction resulted by cavern shrinkage is one of the common risk types in the operation phase of salt cavern gas storage. Cavern shrinkage risk will lead to damage or collapse of cavern wall rock, even serious accidents. Aimed at the possible cavern shrinkage risk during operation phase of salt cavern gas storage, volumetric shrinkage formula of steady state creep phase is derived on the condition of spherical cavern with constant internal pressure in the limitless and ideal salt rock. Combined with the cavern shrinkage risk classification of salt cavern gas storage, the limit state equation of cavern volume shrinkage is created. On the assumption that every random variable in the limit state equation follows normal distribution, probability of risk occurrence under different levels is calculated using reliability analysis. Then the change regularity of stress-difference between grostress and internal pressure and risk probability of every level is analyzed. Lastly, the elastic deformation, initial creep deformation and accelerated creep deformation are taken into consideration and the calculations result is discussed. The research results can provide theoretical reference for the operation management of salt cavern gas storage.

关键词： Rock mechanics

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Dynamic Response and Crack Detection of Multi-span Simple Beam under Moving Loads

Dynamic Response and Crack Detection of Multi-span Simple Be...

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第四届国际机械工程与力学会议

作者： Jun ZHAO Zhenhua NIE Hongwei MA College of Science & Engineering Jinan University The Key Laboratory of Disaster Forecast and Control in Engineering Ministry of Education of China

This paper is to show the potential of the crack detection method based on Multi-resolution Analysis(MRA) of wavelet, which depends on the response of a single point on multi-span beam with concentrated moving loads. When moving along the structure, the moving loads cause small distortions in the dynamic response of the beam-like structure at the crack locations. In general, these small distortions are difficult to detect visually. An ANSYS model of a cracked multi-span beam is established. The moving loads are modeled by shifting the point of the concentrated force. The response at mid-span of 3-span beam is calculated with Wavelet Multi-Resolution Analysis (MRA) method, and the cracks on the multi-span beams can be identified by the position of peaks of the coefficient curves. Furthermore, with the superposition principle, the key parameter of dynamic response of the multi-span beams can be identified. Finally, The effects of results with multiple cracks location and appropriate wavelets are discussed in detail. The proposed method is applicable for low velocity-movements while high velocity-movements are not recommended.

关键词： Moving loads, Crack detection, Multi-span beam, Multi-resolution Analysis of Wavelet

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FAR FIELD SOLUTION OF SH-WAVE SCATTERED BY A CAVITY WITH ARBITRARY SHAPE IN ANISOTROPIC MEDIUM

FAR FIELD SOLUTION OF SH-WAVE SCATTERED BY A CAVITY WITH ARB...

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The 2011 Symposium on Piezoelectricity,Acoustic Waves and Device Applications(2011年全国压电和声波理论及器件技术研讨会)

作者： Zhi-gang Chen Jia-long Wu Key Lab of Disaster Forecast and Control in Engineering Ministry of Education Jinan University Gu Department of Mechanics and Civil Engineering Jinan University Guang Zhou 510632 China

Based on the method of complex functions, the SH-wave scattered by a cavity with arbitrary shape in infinite anisotropic medium is investigated, and a far field solution of displacement is presented. As a result, the far field properties of the SH-wave scattered by circular, elliptical and square cavities in an anisotropic elastic medium with a symmetry plane are analyzed and some curves describing the far field properties of scattering SH-wave are obtained. The results show that the far field characteristic properties of the scattering SH-wave are determined by the incident wave, the geometric shape and the properties of medium. Additionally, the anisotropy of elastic medium has more significant influence on the far field displacement distribution than isotropy.

关键词： anisotropic medium cavity with arbitrary shape SH wave scattering far field solution complex functions

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Parametric Effect on Bidirectional Moving Vehicle Load Identification

Parametric Effect on Bidirectional Moving Vehicle Load Ident...

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The 2011 International Conference on Mechanical Materials and Manufacturing engineering(ICMMME 2011)

作者： Ling Yu Xuegang Wang Department of Civil Engineering China Three Gorges University Key Laboratory of Disaster Forecast and Control in Engineering Ministry of Education of ChinaJinan University

Parametric effect on bidirectional moving vehicle load identification from plate bridge responses is studied in this *** equation of motion of a plate bridge-bidirectional vehicle system is formulated based on Hamilton principle and is rewritten in a state space form,the bidirectional moving load identification problem is considered as a damped least-squares problem and further solved with the regularization ***,the effect of parameters on identification accuracy is investigated in order to evaluate the effectiveness and robustness of the bidirectional moving load identification method proposed in a companion *** numerical simulations show that the proposed method is correct and effective for identifying the bidirectional moving vehicle loads from bridge responses with an acceptable accuracy,but the selection of parameters should be carefully considered in the identification process.

关键词： Time domain method,moving force identification,vehicle loads,bridge loads

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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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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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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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Analysis of Characteristics of Compound Vibration and Effects to Surrounding Gas Pipeline Caused by Impact and Explosion

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Procedia engineering 2011年 26卷 1835-1843页

作者： Su Hua-you Huang Jin Xiao Ding-jun She Yan-hua College of Environment and Resource Southwest University of Science and Technology Mianyang 621010 China Key Lab. for the Exploitation of Southwestern Resources & the Environmental Disaster Control Engineering Ministry of Education in China Chongqing 40044 China

The vibration load caused by the impact and explosion in construction exerts great influence on the surrounding earth. Therefore, the safe operating condition of gas pipeline is seriously influenced. For the first time, by use of smart microseismic monitoring system, such vibration caused by the impact and explosion is monitored and analyzed. First, it reveals the transmission law of vibrating wave forms. Second, the coupling calculating models of pipeline earth under the influence of vibration is built. Finally, the characteristics of exerted force and transformation of earth-pipeline system are analyzed. According to these microseismic data obtained from the spot and numerical simulation method, the dynamic response of underground pipeline under compound vibration is studied; nonlinear mathematical model theory and method for coupling effects of earth and pipeline are built; the effects of vibration to pipeline are assessed; the feasible assessing method of safe operating condition of gas pipeline under vibration is explored and developed.

关键词： vibration load microseismic monitoring blasting gas pipeline

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