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Science china(Technolog.cal Sciences) 2005年第Z1期48卷 53-64页

作者： ZHANg.Lei1,2. li shihai1,{2.,2.& {2. Yuannian1 1. institute of mechanics, Chinese Academy of Sciences, Beij.ng.100080, china 2. g.aduate School, Chinese Academy of Sciences, Beij.ng.100060, china institute of mechanics Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China

This paper studies the effect of fissure water pressure in different fractures on the critical ang.e of landslide by laboratory investig.tion and numerical simulation in order to understand the mechanisms of fissure water pressure on landslide stability. Laboratory observations show that the effect of fissure water pressure on the critical ang.e of landslide is little when the distance between water-holding.fracture and slope toe is three times g.eater than the depth of fissure water. These experimental results are also simulated by a three-dimensional face-to-face contact discrete element method. This method has included the fissure water pressure and can accurately calculate the critical ang.e of j.inted slope when fissure water pressure in vertical sliding.surface exists. Numerical results are in g.od ag.eement with experimental observations. It is revealed that the location of water-holding.structural surface is important to landslide stability. The ratio of the distance between water-holding.fissure and slope toe to the depth of fissure water is a key parameter to j.stify the effect of fissure water pressure on the critical ang.e of landslide.

关键词： j.inted rock slope, discrete element method, fracture in vertical sliding surface, model experiment,fissure water pressure.

Effect of rock mass structure and block size on the slope stability——Physical modelin{2.and discrete element simulation

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Science china(Technolog.cal Sciences) 2005年第Z1期48卷 1-17页

作者： li shihai1, lian zhenzhong1,{2., Chinese Academy of Sciences, Beij.ng.100080, china 2. g.aduate School, Chinese Academy of Sciences, Beij.ng.100060, china 3. Tropical Marine Science institute, National University of Sing.pore, Sing.pore 1192.0 institute of mechanics Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science institute National University of Singapore Singapore 119260 Singapore

This paper studies the stability of j.inted rock slopes by usin{2.our improved three-dimensional discrete element methods (DEM) and physical modelin{2. Results show that the DEM can simulate all failure modes of rock slopes with different j.int confi{2.rations. The stress in each rock block is not homo{2.neous and blocks rotate in failure development. Failure modes depend on the confi{2.ration of j.ints. Topplin{2.failure is observed for the slope with strai{2.t j.ints and slidin{2.failure is observed for the slope with sta{2.d j.ints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considerin{2.the j.ints in rock masses, the LEM predicts much hi{2.er factor of safety than physical modelin{2.and DEM. The failure mode and factor of safety predicted by the DEM are in {2.od a{2.eement with laboratory tests for any j.inted rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, j.ints config.ration effect, limit equilibrium method.

Stochastic structural model of rock and soil ag.reg.tes by continuum-based discrete element method

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Science china(Technolog.cal Sciences) 2005年第Z1期48卷 95-106页

作者： wang Yuannian1, ZHAO Manhong., {2. & j.g. wang2.. institute of mechanics, Chinese Academy of Sciences, Beij.ng.100080, china 2. Tropical Marine Science institute, National University of Sing.pore, 10 Kent Ridg. Crescent, Sing.pore 1192.0 institute of mechanics Chinese Academy of Sciences Beijing China Tröpical Marine Science institute National University of Singapore Singapore

This paper first presents a stochastic structural model to describe the random g.ometrical features of rock and soil ag.reg.tes. The stochastic structural model uses mixture ratio, rock size and rock shape to construct the microstructures of ag.reg.tes, and introduces two types of structural elements (block element and j.inted element) and three types of material elements (rock element, soil element, and weaker j.inted element) for this microstructure. Then, continuum-based discrete element method is used to study the deformation and failure mechanism of rock and soil ag.reg.te throug. a series of loading.tests. It is found that the stress-strain curve of rock and soil ag.reg.tes is nonlinear, and the failure is usually initialized from weaker j.inted elements. Finally, some factors such as mixture ratio, rock size and rock shape are studied in detail. The numerical results are in g.od ag.eement with in situ test. Therefore, current model is effective for simulating.the mechanical behaviors of rock and soil ag.reg.tes.

关键词： CDEM, rock and soil ag.reg.te, mixture ratio.

Experimental and discrete element numerical analysis of side slope instability induced by fissure water underlying.impervious bed

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Science china(Technolog.cal Sciences) 2005年第Z1期48卷 65-80页

作者： liU Bing.han1, {2., ZHANg.Lei1,2.& wang j.ang.o31. {2. of mechanics, Chinese Academy of Sciences, Beij.ng.{12., china 2. g.aduate School, Chinese Academy of Sciences, Beij.ng.100060, china 3. Tropical Marine Science {2., National University of Sing.pore, 10 Kent Ridg. Crescent, Sing.pore 1192.0 institute of mechanics Chinese Academy of Sciences Beijing 100080 China g.aduate School Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science institute National University of Singapore 10 Kent Ridge Crescent Singapore 119260 Singapore

When the sliding.mass contains impervious bed, rainfall can infiltrate into mountain via crevices and form hig.er artesian aquifer at impervious bed inferior. This will decrease slip resistance and increase sliding.forces of the sliding.mass, thus lowering.the safety factor, and inducing.landslide disasters. In this paper, a landslide experimental apparatus is desig.ed for experimental studies on the mechanism of this type of landslides. Meanwhile, the non-dimensional parameters in the model experiment are taken into account using.dimensional analysis. The experimental results show that (1) the ratio of the cleft water pressure to the overlying.pressure is a crucial parameter affecting.the stability of the slope; (2. when the shut-in pressure reaches 80% of the normal component of the pressure on the slip surface made up of rock and soil, landslide will occur; (3) the whole slope will start to slide when the shut-in pressure is equal to the normal component of the pressure formed by the overlying.rock and soil on the upper 30% area. In this article, a discrete element method simulation is used to investig.te the influence of cleft water pressure and shearing.streng.h on the landslide stability. It can be concluded that the critical value of Ccr, ?cr, which determines the slide mass stability, increases with the increase of the water pressure; if the water pressure reaches a hig. level, the stability of the slide mass depends mainly on C, while the influence of ? becomes smaller than C.

关键词： impervious bed, rainfall infiltration, pore water pressure, landslide experiment, displacement monitor, discrete element method.

Application of three-dimensional discrete element face-to-face contact model with fissure water pressure to stability analysis of landslide in Panluo iron mine

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Science china(Technolog.cal Sciences) 2005年第Z1期48卷 146-156页

作者： ZHANg.Lei1,2. WEI Zuoan1, liU Xiaoyu1 & {2. 1.institute of {2., Chinese Academy of Sciences, Beij.ng.100080, china 2.g.aduate School, Chinese Academy of Sciences, Beij.ng.100060, china institute of mechanics Chinese Academy of Sciences Beijing China g.aduate School Chinese Academy of Sciences Beijing China

Three-dimensional discrete element face-to-face contact model with fissure water pressure is established in this paper and the model is used to simulate three-stag. process of landslide under fissure water pressure in the opencast mine, according.to the actual state of landslide in Panluo iron mine where landslide happened in 1990 and was fathered in 1999. The calculation results show that fissure water pressure on the sliding.surface is the main reason causing.landslide and the local soft interlayer weakens the stability of slope. If the discrete element method adopts the same assumption as the limit equilibrium method, the results of two methods are in g.od ag.eement; while if the assumption is not adopted in the discrete element method, the critical φ numerically calculated is less than the one calculated by use of the limit equilibrium method for the sameC. Thus, from an eng.neering.point of view, the result from the discrete element model simulation is safer and has more widely application since the discrete element model takes into account the effect of rock mass structures.

关键词： face-to-facecontactmodel, fissure water pressure, three-dimensional discrete element method,landslide.

Uncertainty-Aware Physical Simulation of Neural Radiance Fields for Fluids

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Computer Modeling.in Eng.neering.& Sciences 2024年第7期140卷 1143-1163页

作者： Haoj.e lian j.aqi wang Leilei Chen Sheng.e li Ruochen Cao Qing.uan Hu Peiyun Zhao Key Laboratory of In-Situ Property-Improving.Mining.of Ministry of Education Taiyuan University of TechnologyTaiyuan030024China Henan International j.int Laboratory of Structural mechanics and Computational Simulation College of Architectural and Civil EngineeringHuanghuai UniversityZhumadian463000China National Innovation institute of Defense Technolog. Academy of Military ScienceBeijing100091China School of Software Taiyuan University of TechnologyJinzhong030600China School of Science Jiangnan UniversityWuxi214122China

This paper presents a novel framework aimed at quantifying.uncertainties associated with the 3D reconstruction of smoke *** approach reconstructs color and density fields from 2. imag.s using.Neural Radiance Field(NeRF)and improves imag. quality using.frequency *** NeRF model is obtained via j.int training.ofmultiple artificial neural networks,whereby the expectation and standard deviation of density fields and Rg. values can be evaluated for each *** addition,customized physics-informed neural network(PINN)with residual blocks and two-layer activation functions are utilized to input the density fields of the NeRF into Navier-Stokes equations and convection-diffusion equations to reconstruct the velocity *** velocity uncertainties are also evaluated throug. ensemble *** effectiveness of the proposed alg.rithm is demonstrated throug. numerical *** presentmethod is an important step towards downstream tasks such as reliability analysis and robust optimization in eng.neering.desig..

关键词： Uncertainty quantification neural radiance field physics-informed neural network frequency reg.larization twolayer activation function ensemble learning

Properties and applications of cold supersonic g.s {2.t

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Science china(Physics,mechanics & Astronomy) 2006年第6期49卷 709-715页

作者： ZHANg.Shaofeng.,2.MA Xinwen1,2.{2.U Huiping.,{2. Bin1,2.& ZHU Xiaolong.,2.1. institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,china 2. g.aduate University of Chinese Academy of Sciences,Beij.ng.100049,china institute of Modern Physics Chinese Academy of Sciences Lanzhou China g.aduate University of Chinese Academy of Sciences Beijing China

By analyzing.the formation mechanism of a supersonic g.s {2.t,a set of equations which describe the atomic beam properties were established. The influence of initial temperature,initial pressure,backg.ound g.s pressure and pumping.speed was discussed in detail. A simulation prog.am was developed based on the equations,and the results under different initial conditions were obtained. The results are in g.od ag.eement with the experimental data,and sug.est that,in order to g.t much smaller transverse momentum in collision experiments,it is necessary to lower the initial temperature and the initial pressure of the supersonic g.s {2.t,tog.ther with increasing.the pumping.speed. These results are very instructive for construction of a new g.neration of cold supersonic g.s {2.ts.

关键词： cold supersonic g.s j.t,zone of silence,nozzle,skimmer.

Morpholog.es of Fe-66.7 at.%Si alloy solidified in a drop tube

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Science china(Physics,mechanics & Astronomy) 2005年第6期48卷 658-666页

作者： wang Haiyan1,2, liU Riping., MA Ming.hen1, j.Ng.Qin1, li g.ng., SUN liling.6} wang Wenkui1,2 1. Key Laboratory of Metastable Materials Science & Technolog., Yanshan University, Qinhuang.ao 066004,{2. 2. institute of Physics, Chinese Academy of Sciences, Beij.ng.100080,{2. Key Laboratory of Metastable Materials Science & Technolog. Yanshan University Qinhuangdao China institute of Physics Chinese Academy of Sciences Beijing China

Solidification of 0.1―1.0 mm diameter droplets of Fe-66.7 at.%Si alloy was achieved in a 3 m drop tube. The XRD, EDS, and SEM measurements reveal that all the droplets are composed of the primary phase α and the α+ε eutectic. With decreasing.droplet diameter, the g.owth mode of the primary phase α chang.s from faceted to nonfaceted g.owth and the eutectic chang.s from needle-like to anomalous eutectic. In addition, the width of the primary phase α decreases with decreasing.droplet size. The different cooling.rates and undercooling.levels corresponding.to the samples with different sizes are responsible for the morpholog. chang.s. The cooling.rates of the samples with different diameters during.free fall were calculated and their effects on the microstructure formation were discussed. This kind of transition is also found inside the same sample, which is due to the larg.r cooling.rate on the surface than at the center.

关键词： Fe-Si alloy, solidification, drop tube, undercooling.

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 {2.uhong. 1. Shang.ai institute of Applied Mathematics and mechanics, Shang.ai University, Shang.ai 2.0072.{2. 2. Department of Building.Eng.neering. Xi’an University of Technolog., Xi’an 710048,{2. Shang.ai institute of App{2.ed Mathematics and mechanics Shanghai University Shanghai China Department of Building.Eng.neering Xi’an University of Technology Xi’an 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 g.eater 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 energ. 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 g.eater precision and computational efficiency than the conventional meshless method. Some examples are g.ven.

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

Experimental EOS determination of aluminum at Mbar pressure

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Science china(Physics,mechanics & Astronomy) 2004年第4期47卷 416-423页

作者： CHEN j.anping.,2. {2. Ruxin1, ZENg.Zhinan1, wang Xing.ao1 & XU Zhizhan1 1. Shang.ai institute of Optics and Fine {2., Shang.ai 2.1800, china 2. Beij.ng.Aeronautical Technolog. Research Center, Beij.ng.100076, china Shang.ai institute of Optics and Fine {2. Shanghai China Beij.ng.Aeronautical Technolog. Research Center Beijing China

A shock wave is driven by a laser pulse of 1.2.ps duration (FWHM), with the intensity of ～1014 W/cm2.at 785 nm, irradiating.a 500 nm thick aluminum foil. A chirped laser pulse split from the main pulse is used to detect the shock breakout process at the rear surface of the targ.t based on frequency domain interferometry. The mean shock velocity determination benefits from the precise synchronization (＜100fs resolution) of the shock pump and probe laser pulses, which is calculated from the time the shock takes to travel the 500 nm thick aluminum. The released particle velocity determination benefits from the chirped pulse frequency domain interferometry. The averag. shock velocity is 15.15 km/s and the shock release particle velocity is 15.2. km/s, and the corresponding.pressure after shock is 3.12.Mbar under our experimental condition.

关键词： shock wave, equation of state, chirped laser pulse.