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Enhanced Hoek-Brown(H-B)criterion for rocks exposed to chemical corrosion

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International Journal of Mining Science and Technology 2024年第5期34卷 609-630页

作者： Hao Li Leo Pel zhenjiang You David Smeulders department of Mechanical engineering Eindhoven University of TechnologyEindhoven 5600 MBthe Netherlands department of Applied Physics Eindhoven University of TechnologyEindhoven 5600 MBthe Netherlands Center for Sustainable Energy and Resources School of EngineeringEdith Cowan UniversityJoondalupWA 6027Australia School of Chemical engineering The University of QueenslandBrisbaneQLD 4072Australia Gas and Energy Transition Research Centre The University of QueenslandBrisbaneQLD 4072Australia

Underground constructions often encounter water environments,where water–rock interaction can increase porosity,thereby weakening engineering ***,the failure criterion for chemically corroded rocks becomes essential in the stability analysis and design of such *** study enhances the applicability of the Hoek-Brown(H-B)criterion for engineering structures operating in chemically corrosive conditions by introducing a kinetic porosity-dependent instantaneous mi(KPIM).A multiscale experimental investigation,including nuclear magnetic resonance(NMR),X-ray diffraction(XRD),scanning electron microscopy(SEM),pH and ion chromatography analysis,and triaxial compression tests,is employed to quantify pore structural changes and their linkage with the strength responses of limestone under coupled chemical-mechanical(C-M)*** employing ion chromatography and NMR analysis,along with incorporating the principles of free-face dissolution theory accounting for both congruent and incongruent dissolution,a kinetic chemical corrosion model is *** model aims to calculate the kinetic porosity alterations within rocks exposed to varying H+concentrations and ***,utilizing the generalized mixture rule(GMR),the kinetic porositydependent mi is *** of the KPIM-enhanced H-B criterion using compression test data from 5 types of rocks demonstrated a high level of consistency between the criterion and the experimental results,with a coefficient of determination greater than 0.96,a mean absolute percentage error less than 4.84%,and a root-mean-square deviation less than 5.95 ***,the physical significance of the porosity-dependent instantaneous mi is clarified:it serves as an indicator of a rock’s capacity to leverage the confining pressure effect.

关键词： Hoek-Brown(H-B)criterion Instantaneous mi Kinetic porosity-dependency Chemical corrosion Compressive strength

Constructing Three-Dimension Space Graph for Outlier Detection Algorithms in Data Mining

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Wuhan University Journal of Natural Sciences 2004年第5期9卷 585-589页

作者： ZHANG Jing 1,2., SUN Zhi-hui 1 1.department of Computer Science and engineering, Southeast University, Nanjing 2.0096, {2., china 2.department of Electricity and Information engineering, {2. University, zhenjiang 2.2.01, {2., china department of Computer Science and engineering Southeast University. Nanjing 210096 Jiangsu China

Outlier detection has very important applied value in data mining literature. Different outlier detection algorithms based on distinct theories have different definitions and mining processes. The three-dimensional space graph for constructing applied algorithms and an improved GridOf algorithm were proposed in terms of analyzing the existing outlier detection algorithms from criterion and theory. Key words outlier - detection - three-dimensional space graph - data mining CLC number TP 311. 13 - TP 391 Foundation item: Supported by the National Natural Science Foundation of china (70371015)Biography: ZHANG Jing (1975-), female, Ph. D, lecturer, research direction: data mining and knowledge discovery.

关键词： outlier detection three-dimensional space graph data mining

Gas kinetic algorithm for flows in Poiseuille-like microchannels using Boltzmann model equation

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Science china(Physics,mechanics & Astronomy) 2005年第4期48卷 496-512页

作者： LI Zhihui1,2. ZHANG Hanxin1 & FU Song2.⒈ National Laboratory for CFD, Hypervelocity Aerodynamics Institute,china Aerodynamics Research and Development Center,Mianyang 62.000,china {2.,Tsinghua University,Beijing 100084,china 1. National Laboratory for CFD Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development Center 621000 Mianyang China 2. department of engineering {2. Tsinghua University 100084 Beijing China

The gas-kinetic unified algorithm using Boltzmann model equation have been extended and developed to solve the micro-scale gas flows in Poiseuille-like micro-channels from Micro-Electro-Mechanical Systems (MEMS). The numerical modeling of the gas kinetic boundary conditions suitable for micro-scale gas flows is presented. To test the present method, the classical Couette flows with various Knudsen numbers, the gas flows from short microchannels like plane Poiseuille and the pressure-driven gas flows in two-dimensional short microchannels have been simulated and compared with the approximate solutions of the Boltzmann equation, the related DSMC results, the modified N-S solutions with slip-flow boundary theory, the gas-kinetic BGK-Burnett solutions and the experimental data. The comparisons show that the present gas-kinetic numerical algorithm using the mesoscopic Boltzmann simplified velocity distribution function equation can effectively simulate and reveal the gas flows in microchannels. The numerical experience indicates that this method may be a powerful tool in the numerical simulation of micro-scale gas flows from MEMS.

关键词： Boltzmann model equation, discrete velocity ordinate method, finite-difference scheme, Couette flow, Poiseuille flow, gas flow in short-microchannel.

The numerical method for three-dimensional impact with friction of multi-rigid-body system

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Science china(Physics,mechanics & Astronomy) 2006年第1期49卷 102-118页

作者： ZHAO Zhen1,2. LIU Caishan2.& CHEN Bin2.1. Beijing Institute of Graphic Communication, Beijing 102.00, china 2. department of {2. & engineering Science, Peking University, Beijing 100871, china Beijing Institute of Graphic Communication Beijing 102600 China department of mechanics & {2. Science Peking University Beijing 100871 China

The differential equations for planar impacts reduce to an algebraic form, and can be easily solved. For three dimensional impacts with friction, there is no closed-form solution, and numerical integration is required due to the swerve behavior of tangential impulse during collisions. The dynamic governing equations in the impact process are built up in impulse space based on the Lagrangian equation in this paper. The coefficient of restitution defined by Poisson is used as the condition of impact termination. A valid nu- merical method for solving three-dimensional frictional impact of multi-rigid body system is established. The singular cases of tangential movement in sticking point are especially noticed and analyzed. Several examples are present to reveal the different kinds of tan- gential movement modes varied with the normal impulse during collision.

关键词： multi-rigid body, impact, friction.

The reliability of the improved e^N method for the transition prediction of boundary layers on a flat plate

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Science china(Physics,mechanics & Astronomy) 2012年第5期55卷 837-843页

作者： SU CaiHong1,2.1 department of mechanics,Tianjin University,Tianjin 300072.{2. 2.Tianjin Key Laboratory of Modern engineering mechanics,Tianjin 300072.{2. 1. department of mechanics Tianjin University Tianjin 300072 China2. Tianjin Key Laboratory of Modern Engineering Mechanics Tianjin 300072 China

The transition criterion in the improved eN method is that transition would occur whenever the velocity amplitude of disturbance reaches 1%-2. of the free stream velocity,while in the conventional eN method,the N factor is an empirical *** this paper the reliability of this key assumption in the improved eN method is checked by results of transition prediction by using the Parabolized Stability Equations(PSE).Transition locations of an incompressible boundary layer and a hypersonic boundary layer at Mach number 6 on a flat plate are predicted by both the improved eN method and the PSE *** from both methods agree fairly well with each other,implying that the transition criterion proposed in the improved eN method is reliable.

关键词： transition prediction boundary layer eN PSE

Micromechanical analysis of interaction energy for SMA reinforced composite

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Science china(Technological Sciences) 2009年第3期52卷 610-616页

作者： ZHU YuPing1,2. DUI GuanSuo1 & DUO Liu3 1 Institute of mechanics, Beijing Jiaotong University, Beijing 100044, china {2., jiangsu University, zhenjiang 2.2.13, china 3 State Key Lab of Crystal Materials, Shandong University, Jinan 2.0100, china Institute of mechanics Beijing Jiaotong University Beijing 100044 China department of engineering {2. Jiangsu University Jiangsu Zhenjiang 212013 China State Key Lab of Crystal Materials Shandong University Jinan 250100 China

The energy of the interaction between the matrix and the inclusions in shape memory alloy (SMA) re- inforced composite is one of the most important and complicated parts in thermodynamic constitutive theory. In this paper, the interaction energy is derived based on the classical theory of micromechanics and the thermodynamic theory. The SMA composite is treated as three phases, namely the austenitic phase, the martensite phase and the matrix phase. The interaction among the three phases is analyzed in a way close to the fact. The present expression is used to calculate the interaction energy of a typical SMA composite with attentions paid to understand of the effects of the matrix material, the fiber ge- ometry, and the fiber/matrix volume ratio. It is shown that the method developed in this paper is credible compared with the references. Some useful conclusions are obtained.

关键词： shape memory alloy interaction energy SMA composite micromechanics thermodynamics

A complex variable meshless method for fracture problems

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Science china(Physics,mechanics & Astronomy) 2006年第1期49卷 46-59页

作者： CHENG Yumin1 & LI Jiuhong2.1. Shanghai Institute of Applied Mathematics and mechanics, Shanghai University, Shanghai 2.0072. china 2. {2. of Building engineering, Xi’an University of Technology, Xi’an 710048, china Shanghai Institute of Applied Mathematics mechanics Shanghai University Shanghai 200072 China department of Building engineering Xi’an University of Technology Xi’an 710048 China

Based on the moving least-square (MLS) approximation, the complex variable moving least-square approximation (CVMLS) is discussed in this paper. The complex variable moving least-square approximation cannot form ill-conditioned equations, and has greater precision and computational efficiency. Using the analytical solution near the tip of a crack, the trial functions in the complex variable moving least-square approxi- mation are extended, and the corresponding approximation function is obtained. And from the minimum potential energy principle, a complex variable meshless method for fracture problems is presented, and the formulae of the complex variable meshless method are obtained. The complex variable meshless method in this paper has greater precision and computational efficiency than the conventional meshless method. Some examples are given.

关键词： moving least-square approximation, complex variable moving least-square approximation, meshless method, complex variable meshless method, fracture.

Effects of shear keys on nonlinear seismic responses of an arch-gravity dam

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Science china(Technological Sciences) 2011年第S1期54卷 18-27页

作者： JIANG ShouYan 1,DU ChengBin 1 &YUAN JuWei 2.1 department of engineering {2.,Hohai University,Nanjing 2.0098,china 2.jiangsu Hongji Science and Technology Company.,Ltd.,Nanjing 2.0008,china 1. department of engineering {2. Hohai University Nanjing 210098 China2. Jiangsu Hongji Science and Technology Company. Ltd. Nanjing 210008 China

In the paper,the added tangential nonlinear springs are introduced to represent the effects of one-way and two-way shear keys. The added tangential stiffness coefficient is relative to the joint opening and the relative tangential movement and determined numerically by using a refined model of shear *** user subroutine of nonlinear spring elements has been implemented into ABAQUS *** seismic responses of an arch-gravity dam are mainly *** is shown by the results that a significant increase of about 17%-30%in joint opening can be observed for the dam with one-way shear keys;the two-way shear keys are beneficial to restrain the sliding displacement along both the radial and vertical directions,whereas the one-way shear keys mainly restrain the displacement along the radial direction;for the dam with shear keys,the maximum arch stress is increased,the cantilever stress is reduced,and the location of the maximum cantilever stress is also moved from the dam heel to the midheight of the cantilever.

关键词： seismic responses arch-gravity dam contraction joints shear keys nonlinear spring elements

Boundary element-free method for elastodynamics

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Science china(Physics,mechanics & Astronomy) 2005年第6期48卷 641-657页

作者： CHENG Yumin1 & PENG Miaojuan2.1. Shanghai Institute of Applied Mathematics and mechanics, Shanghai University, Shanghai 2.0072. china 2. {2. of Civil engineering, Shanghai University, Shanghai 2.0072. china 1. Shanghai Institute of Applied Mathematics and mechanics Shanghai University 200072 Shanghai China 2. department of Civil engineering Shanghai University 200072 Shanghai China

The moving least-square approximation is discussed first. Sometimes the method can form an ill-conditioned equation system, and thus the solution cannot be obtained correctly. A Hilbert space is presented on which an orthogonal function system mixed a weight function is defined. Next the improved moving least-square approximation is discussed in detail. The improved method has higher computational efficiency and precision than the old method, and cannot form an ill-conditioned equation system. A boundary element-free method (BEFM) for elastodynamics problems is presented by combining the boundary integral equation method for elastodynamics and the improved moving least-square approximation. The boundary element-free method is a meshless method of boundary integral equation and is a direct numerical method compared with others, in which the basic unknowns are the real solutions of the nodal variables and the boundary conditions can be applied easily. The boundary element-free method has a higher computational efficiency and precision. In addition, the numerical procedure of the boundary element-free method for elastodynamics problems is presented in this paper. Finally, some numerical examples are given.

关键词： moving least-square approximation, improved moving least-square approximation, elastodynamics, boundary integral equation, meshless method, boundary element-free method, Fourier eigen transform.