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Transactions of Tianjin University 2008年第5期14卷 353-357页

作者： ma guowei HUANg Xin LI Jianchun school of civil and Environmental engineering Nanyang Technological University Nanyang Avenue Singapore 639798 Singapore

The soil-structure interaction (SSI) decoupling is applied to simplify buried structure against internal blast load as spring effect. Shear failure, bending failure and combined failure modes are considered based on five transverse velocity profiles for the rigid-plastic structural element. The critical equations for shear and bending failure are derived respectively. Pressureimpulse diagrams are accordingly developed to assess damage of the buried structures against internal blast load. Comparison is done to show influences of soil-structure interaction and shear-to-bending strength ratio of a structural element. A case study is conducted to show the application of damage assessment to a reinforced concrete beam element of buried structure.

关键词： combined failure pressure-impulse diagram buried structure blast load damage assessment

An extended displacement discontinuity method for analysis of stress wave propagation in viscoelastic rock mass

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Journal of Rock Mechanics and geotechnical engineering 2011年第1期3卷 73-81页

作者： L.F.Fan1,F.Ren1,g.w.ma2 1 school of civil and Environmental engineering,Nanyang Technological University,singapore,639798,singapore 2 school of civil and resource engineering,The University of western Australia,Crawley,wA 6009,Australia school of civil and Environmental engineering Nanyang Technological University Singapore 639798 Singapore school of civil and resource engineering The University of Western Australia Crawley WA 6009 Australia

An extended displacement discontinuity method (EDDM) is proposed to analyze the stress wave propagation in jointed viscoelastic rock mass (VRM).The discontinuities in a rock mass are divided into two *** primary group with an average geometrical size larger than or in the same order of magnitude of wavelength of a concerned stress wave is defined as 'macro-joints',while the secondary group with a high density and relatively small geometrical size compared to the wavelength is known as 'micro-defects'.The rock mass with micro-defects is modeled as an equivalent viscoelastic medium while the macro-joints in the rock mass are modeled explicitly as physical *** properties of a micro-defected sedimentary rock are obtained by longitudinally impacting a cored long sedimentary rod with a *** propagation coefficient and dynamic viscoelastic modulus are *** EDDM is then successfully employed to analyze the wave propagation across macro-joint in *** effect of the rock viscosity on the stress wave propagation is evaluated by comparing the results of VRM from the presented EDDM with those of an elastic rock mass (ERM) from the conventional displacement discontinuity method (CDDM).The CDDM is a special case of the EDDM under the condition that the rock viscosity is *** of the reflected and transmitted waves shows that the essential rock viscosity has a significant effect on stress wave *** a short propagation distance of a stress wave is considered,the results obtained from the CDDM approximate to the EDDM solutions,however,when the propagation distance is sufficiently long relative to the wavelength,the effect of rock viscosity on the stress wave propagation cannot be ignored.

关键词： stress wave propagation extended displacement discontinuity method (EDDM) viscoelastic rock mass (VRM) micro-defect macro-joint

Blast Protection Shelter by Using Hollow Steel Filled with Recycled Concrete

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Transactions of Tianjin University 2008年第6期14卷 426-429页

作者： LI Jianchun, HUANg Xin HUANg Xin ma guowe school of civil and Environmental engineering Nanyang Technological University Singapore 639798

Under extreme loading condition,a shelter will provide a safe place to protect people from injury caused by blast wave and *** order to save resource and reuse waste materi-als,a new design concept for blast protection shelter was *** new construction was composed of I-section steel panel or C-channel steel panel filled with recycled concrete *** compaction process of the recycled concrete aggregate filled in the steel construction was ex-perimentally investigated.A single storey shelter based on the proposed design concept was nu-merically simulated by using LS-DYNA *** the 3D numerical model,three walls were de-signed using I-section steel and one wall using C-channel steel,and all of the four walls were filled with recycled concrete *** penetration analysis was done by using *** penetration tests were also carried out by using a gas *** is found that the proposed shelter based on the design concept is effective for blast protection.

关键词： hollow steel panel recycled concrete aggregate shelter LS-DYNA simulation

Ash removal from inferior coal via ammonium fluoride roasting and simultaneous yield of white carbon black

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International Journal of Mining Science and Technology 2024年第2期34卷 261-279页

作者： Xuqin Duan Shuaiyu Lu Yuxiao Fu Jiazhe Zhang Tong Liu Jian ma school of civil and resource engineering University of Science&Technology BeijingBeijing 100083China State Key Laboratory for Efficient Mining of Metal Mines University of Science&Technology BeijingBeijing 100083China China Coal Processing and Utilizaiton Association Beijing 100013China

The quality upgrading and deashing of inferior coal by chemical method still faces great *** dangers of strong acid,strong alkali,waste water and exhaust gas as well as high cost limit its industrial *** paper systematically investigates the ash reduction and desilicification of two typical inferior coal utilizing ammonium fluoride roasting *** the optimal conditions,for fat coal and gas coal,the deashing rates are 69.02%and 54.13%,and the desilicification rates are 92.64%and 90.27%,*** molar dosage of ammonium fluoride remains consistent for both coals;however,the gas coal,characterized by a lower ash and silica content(less than half that of the fat coal),achieves optimum deashing effect at a reduced time and *** majority of silicon in coal transforms into gaseous ammonium fluorosilicate,subsequently preparing nanoscale amorphous silica with a purity of 99.90%through ammonia *** of the fluorine in deashed coal are assigned in inorganic minerals,suggesting the possibility of further fluorine and ash removal via *** research provides a green and facile route to deash inferior coal and produce nano-scale white carbon black simultaneously.

关键词： Inferior coal Deashing treatment Silicon recycling Ammonium fluoride roasting white carbon black

Modelling of multi-bodies in close proximity under water waves——Fluid resonance in narrow gaps

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Science China(Physics,Mechanics & Astronomy) 2011年第1期54卷 16-25页

作者： LU Lin1,2,TENg Bin3,CHENg Liang 4,SUN Liang5 & CHEN XiaoBo6 1 Center for Deepwater engineering,Dalian University of Technology,Dalian 116024,China 2 State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,China 3 State Key Laboratory of Coastal and Offshore engineering,Dalian University of Technology,Dalian 116024,China 4 school of civil and resource engineering,The University of western Australia,Crawly 6003,Australia 5 Centre for Offshore Research and engineering,Department of civil engineering,National University of singapore,117576,singapore 6 Research Department,Bureau Veritas,Neuilly-Sur-Seine,92570,France 1. Center for Deepwater engineering Dalian University of Technology Dalian 116024 China2. State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116024 China3. State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China4. School of Civil and Resource Engineering The University of Western Australia Crawly 6003 Australia5. Centre for Offshore Research and Engineering Department of Civil Engineering National University of Singapore Singapore 117576 Singapore6. Research Department Bureau Veritas Neuilly-Sur-Seine 92570 France

Viscous fluid model and potential flow model with and without artificial damping force(f=-μV,μ the damping coefficient and V the local averaging flow velocity) are employed in this work to investigate the phenomenon of fluid resonance in narrow gaps between multi-bodies in close proximity under water *** numerical results are compared with experimental data available in the *** comparison demonstrates that both the viscous fluid model and the potential flow model are able to predict the resonant frequency reasonably *** the conventional potential flow model(without artificial damping term) significantly over-predicts the wave height in narrow gaps around the resonant *** order to calibrate the appropriate damping coefficient used for the potential model and make it work as well as the viscous fluid model in predicting the resonant wave height in narrow gaps but with little computational efforts,the dependence of damping coefficient μ on the body geometric dimensions is examined considering the parameters of gap width Bg,body draft D,body breadth ratio Br and body number n(n = 2,3),where Br = BB/BA for the case of two bodies(Body A and Body B) with different breadths of BA and BB,*** was confirmed that the damping coefficient used for the potential flow model is not sensitive to the geometric dimensions and spatial *** was found that μ∈ [0.4,0.5] may guarantee the variation of Hg/H0 with kh to be generally in good agreement with the experimental data and the results of viscous fluid model,where Hg is the excited wave height in narrow gaps under various dimensionless incident wave frequencies kh,H0 is the incident wave height,k = 2π/L is the wave number and h is the water depth.

关键词： narrow gap fluid resonance water wave viscous fluid model potential flow model finite element method boundary element method

Simulations of explosion-induced damage to underground rock chambers

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Journal of Rock Mechanics and geotechnical engineering 2011年第1期3卷 19-29页

作者： g.w.ma1,H.Hao1,F.wang2 1 school of civil and resource engineering,The University of western Australia,Crawley,wA 6009,Australia 2 Defense Science and Technology Agency,singapore,109679,singapore school of civil and resource engineering The University of Western Australia Crawley WA 6009 Australia Defense Science and Technology Agency Singapore 109679 Singapore

A numerical approach is presented to study the explosion-induced pressure load on an underground rock chamber wall and its resultant damage to the rock *** simulations are carried out by using a modified version of the commercial software *** different criteria,i.e.a peak particle velocity (PPV) criterion,an effective strain (ES) criterion,and a damage criterion,are employed to examine the explosion-induced damaged zones of the underground rock *** results show that the charge chamber geometry,coupling condition and charge configuration affect significantly the dynamic pressure exerted on the rock chamber *** the chamber is *** inaccurate approximation of pressure boundary ignoring the influences of these factors would result in an erroneous prediction of damaged area and damage intensity of the charge *** PPV criterion yields the largest damaged zone while the ES criterion gives the smallest *** presented numerical simulation method is superior in consideration of the chamber geometry,loading density,coupling condition and rock *** predicted damage intensity of rock mass can be categorized quantitatively by an isotropic damage *** separation distance of adjacent chambers for a specific charge weight is also estimated.

关键词： underground explosion rock damage numerical simulation safe separation distance

Biomineralization and mineralization using microfluidics:A comparison study

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Journal of Rock Mechanics and geotechnical engineering 2024年第2期16卷 661-669页

作者： Yang Xiao Xiang He guoliang ma Chang Zhao Jian Chu Hanlong Liu Key Laboratory of New Technology for Construction of Cities in Mountain Area Chongqing UniversityChongqing400045China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing400045China school of civil engineering Chongqing UniversityChongqing400045China school of civil and Environmental engineering Nanyang Technological UniversitySingapore

Biomineralization through microbial process has attracted great attention in the field of geotechnical engineering due to its ability to bind granular materials,clog pores,and seal *** minerals formed by biomineralization are generally the same as that by mineralization,their mechanical behaviors show a significant *** study aims to figure out the differences between biomineralization and mineralization processes by visualizing and tracking the formation of minerals using *** biomineralization and mineralization processes occurred in the Y-shaped sandcontaining microchip that mimics the underground sand *** from different areas in the reaction microchannel of microchips were captured to directly compare the distribution of *** size and numbers from different reaction times were measured to quantify the differences between biomineralization and mineralization processes in terms of crystal *** showed that the crystals were precipitated in a faster and more uncontrollable manner in the mineralization process than that in the biomineralization process,given that those two processes presented similar precipitation *** addition,a more heterogeneous distribution of crystals was observed during the biomineralization *** precipitation behaviors were further explained by the classical nucleation crystal growth *** present microfluidic tests could advance the understanding of biomineralization and provide new insight into the optimization of biocementation technology.

关键词： Microbially induced carbonate precipitation (MICP) Biocementation Crystal Calcium carbonate Nucleation

Analysis of explosion wave interactions and rock breaking effects during dual initiation

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International Journal of Minerals,Metallurgy and materials 2024年第8期31卷 1788-1798页

作者： Renshu Yang Jinjing Zuo Liwei ma Yong Zhao Zhen Liu Quanmin Xie school of civil and resource engineering University of Science and Technology BeijingBeijing 100083China Research Institute of macro-Safety Science University of Science and Technology BeijingBeijing 100083China State Key Laboratory of Precision Blasting Jianghan UniversityWuhan 430056China

In blasting engineering, the location and number of detonation points, to a certain degree, regulate the propagation direction ofthe explosion stress wave and blasting effect. Herein, we examine the explosion wave field and rock breaking effect in terms of shockwave collision, stress change of the blast hole wall in the collision zone, and crack propagation in the collision zone. The produced shockwave on the collision surface has an intensity surpassing the sum of the intensities of the two colliding explosion shock waves. At the collisionlocation, the kinetic energy is transformed into potential energy with a reduction in particle velocity at the wave front and the wavefront pressure increases. The expansion form of the superposed shock wave is dumbbell-shaped, the shock wave velocity in the collisionarea is greater than the radial shock wave velocity, and the average propagation angle of the explosion shock waves is approximately 60°.Accordingly, a fitted relationship between blast hole wall stress and explosion wave propagation angle in the superposition area is *** the experimental conditions, the superimposed explosion wave stress of the blast hole wall is approximately 1.73 times the singleexplosionwave incident stress. The results of the model test and numerical simulations reveal that large-scale radial fracture cracks weregenerated on the blast hole wall in the superimposed area, and the width of the crack increased. The width of the large-scale radial fracturecracks formed by a strong impact is approximately 5% of the blast hole length. According to the characteristics of blast hole wallcompression, the mean peak pressures of the strongly superimposed area are approximately 1.48 and 1.84 times those of the weakly superimposedand nonsuperimposed areas, respectively.

关键词： blasting shock wave collision high-speed schlieren system crack fracture characteristic explosion wave

THREE-PHASE MEDIUM MODEL AND wAVE PROPAgATION ANALYSIS FOR FILLED ROCK JOINT

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THREE-PHASE MEDIUM MODEL AND WAVE PROPAGATION ANALYSIS FOR F...