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Slope Stability Analyses of Outang Landslide Based on the Peak and Residual Shear Streng.h Behavior

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工程科学与技术 2019年第4期51卷 55-68页

作者： YANG Xiuhan VANAPALLI Sai Dept.of Civil eng. Univ.of Ottawa

Most of the natural and compacted fine-grained soil slopes that are in saturated or unsaturated condition undergo a large deformation prior to reaching failure *** slopes should be designed taking account of their strain-softening behavior using the residual shear streng.h (RSS) *** this paper,the slope stability of a recently reactivated Outang landslide near the Three Gorges Dam in China is analyzed based on the RSS parameters of unsaturated *** addition,comparisons are provided in the FOS values of slope using both the peak shear streng.h (PSS) and RSS ***,a series of site investigations of the hydrologic and geologic conditions,ground surface displacements and cracks were *** PSS and RSS behaviors of the sliding soils derived from a series of direct shear test results performed on saturated and unsaturated soil specimens are ***,a series of slope stability analysis were conducted considering the precipitation and Yangtze River water level variation within a representative period of 7 months,based on the PSS and the RSS *** this study,three different scenarios were considered,which include: i) considering only the precipitation with a constant water level;ii) considering only the decrease in water level without rainfall;iii) considering the combination of precipitation and decrease in water *** each scenario,four steps were included to calculate the values of factor of safety (FOS) at different times.1) A steady-state seepage analysis was conducted with a constant total head at 525 m on the left boundary and 175 m on the slope surface below the Yangtze River water *** initial pore water pressures were simulated in the slope under no precipitation and variation of water level.2) A specific boundary condition was applied on the slope surface to model the precipitation and Yangtze River water level variation.A transient seepage analysis was conducted to calculate pore water pres

关键词： unsaturated soil landslide reactivation residual shear streng.h slope stability analysis

Study of Microstructure and Magnetic Properties of Pr-Fe-B-Cu Permanent Magnets by Hot Deformation

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Journal of Rare Earths 2002年第3期20卷 188-192页

作者：陈秀云姜忠良高天明吴严杨昌平朱静 Dept. of Mater. Sci. and eng. Sch. of Mater. Sci. and Eng. Tsinghua Univ. Beijing 100084 China

The relationship between the microstructures and magnetic properties of rare earth cast permanent Pr Fe B Cu alloys by hot deformation was studied. Fine and well aligned column grains can be obtained by using a proper solidification mould with a high cooling rate. The soft magnetic phase α Fe can be removed during proper annealing treatment. Hot pressing can produce the anisotropy and refine the grain size, so that the magnetic properties are greatly improved. The technique has the advantages of simple processing, low cost and high benefit, compared with the common sintering processing. Under the condition of the deformation temperature of 1073 K, 90% strain and strain rate of 40×10 -3 s -1 , the magnetic properties obtained are: B r=1.05 T, i H c=955 kA·m -1 , ( BH ) max =207 kJ·m -3 .

关键词： rare earths hot deformation anisotropy sintering

A Methodology for Curve and Surface Fitting with Adaptive Fairing for Digitized Points

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Journal of Shanghai Jiaotong university(Science) 2006年第4期11卷 460-464页

作者：李大永彭颖红尹忠慰李建新 School of Mechanical eng. Shanghai Jiaotong Univ. School of Mechanical eng. Northeastern Univ.

A new approach for NURBS(Non-uniform rational B-spline) curve and surface fitting for measured points was presented which employs a fairing method applied to digitized point data with discrete curvature. If measured points are used as control points to construct an NURBS curve, then the curvature of each data point corresponding to control point of the constructed curve can be computed. According to the convex hull and local properties of NURBS, based on the curvatures obtained, the measured points can be faired. If faired measured points are used as target points to modify, the constructed curve passing through these faired points can produce a smooth NURBS curve. This paper also presented the justification for utilizing the curvatures of constructed NURBS curve instead of the conventional interpolated curve to fair the measured points. Based on the presented algorithms, some qualities of the constructed curves can be improved.

关键词： non-uniform rational B-splihe (NURBS) fair curvature constructed curve

New artificial boundary condition for saturated soil foundations

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Earthquake eng.neering and eng.neering Vibration 2012年第1期11卷 139-147页

作者： Xu Qiang Chen Jianyun Li Jing Fan Shuli State Key Lab.of Coastal and Offshore eng. Dalian University of Technology Dalian 116023 China School of Civil and Hydraulic eng. Dalian University of Technology Dalian 116023 China

Anew artificial boundary model based on multi-directional transmitting and viscous-spring artificial boundary theories is proposed to absorb stress waves in a saturated soil foundation in dynamic analysis. Since shear waves （S-waves） are the same in a saturated soil foundation and a single-phase medium foundation, a tangential visco-elastic boundary condition for a single-phase medium foundation can also be used for saturated soil foundations. Thus, the purpose of the artificial boundary proposed in this paper is primarily to absorb two types of P-waves in a saturated soil foundation. The main idea is that the stress of the P-waves in the saturated soil foundation is decomposed into two types. The first type of stress, δra＇ is absorbed by the first artificial boundary. The second type of stress, δrb, is balanced by the stress generated by the second artificial boundary. Ultimately, both types of P-waves （fast-P-waves and slow-P-waves） are absorbed by the artificial boundary model proposed in this paper. In particular, note that the fast-P-waves and slow-P-waves are absorbed at the position of the first boundary. Thus, the artificial boundary model proposed herein can simultaneously absorb P-fast waves, P-slow waves and shear waves. Finally, a numerical example is given to examine the proposed artificial boundary model, and the results show that it is very accurate.

关键词： multi-directional transmitting artificial boundary viscous-spring artificial boundary saturated soil foundation Biot's equations

Nonlinear Mixed-Effects Models for Repairable Systems Reliability

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Journal of Shanghai Jiaotong university(Science) 2007年第2期12卷 283-288页

作者：谭芙蓉江志斌郭位裴锡柱 School of Mechanical eng. Shanghai Jiaotong Univ. College of eng. the Univ.of TennesseeKnoxvilleTN 37996USA Dept.of Industrial eng. Hanyang Univ.SeoulKorea

Mixed-effects models,also called random-effects models,are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject,but also to describe the variation among different *** mixed-effects models provide a powerful and flexible tool for handling the unbalanced count *** this paper,nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple *** using this type of models,statistical inferences about the population and all copies can be made when accounting for copy-to-copy *** of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems.

关键词： repairable systems reliability analysis nonlinear mixed-effects models power law process maximum likelihood estimation

Structural Characteristics and Mechanical Properties of Rock Mass in the Field of Tianwan Nuclear Power Plant, China

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Journal of Shanghai Jiaotong university(Science) 2006年第4期11卷 512-517,524页

作者：周念清唐益群邓永华赵在立 Dept. of Geotechnical eng. Tongji Univ. The General Company of East China Survey Foundation eng. of Metallurgical Industry Ministry Hebei Zhonghe Geotechnical eng. Co. Ltd.

The structural characteristics and mechanical properties of the rock mass are important parts of the feasibility study on the nuclear power eng.neering field. In this study, by means of in situ investigation and statistics, the structural plane and joint fissure features of the rock mass were analyzed and discussed at different plots and different depth scopes in the Tianwan Nuclear Power eng.neering field, the rock mass integrality and its weathered degree were evaluated respectively, and especially, the unfavorable geological phenomena of strongly-weathered cystid existing in the field were studied. According to the results of indoor rock mechanical tests, in combination with drilling, the shallow seismic prospecting, sonic logging and point load tests, the statistical results of physical and mechanical indices of rocks at key plots of the field were analyzed, and the design parameters of the field were calculated. It provided scientific basis for the foundation design of the nuclear power plant.

关键词： Tianwan Nuclear Power Plant structural plane joint fissure weathered degree rock mass integrality mechanical property

Seismic Performance of Steel Reinforced Ultra High-streng.h Concrete Columns

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四川大学学报（工程科学版） 2009年第3期41卷 216-222,230页

作者：贾金青 Inst.of Structural eng. Dalian Univ.of Technol.

The seismic performance of steel reinforced ultra-high-streng.h concrete columns(SRSHC) with various shear-span ratios(λ) were studied through a series of *** concrete compressive cube streng.h value of experimental specimens ranged from 92.9 MPa to 108.1 *** main experimental variables affecting seismic performance of specimens were axial load ratio and stirrup reinforcement *** columns(λ=2.75) subjected to low cyclic reversed lateral loads failed mainly in the flexural-shear mode failure and columns(λ≤2.0) subjected to low cyclic reversed lateral loads failed mainly in the shear mode *** force-displacement hysteretic curves and skeleton curves were *** of the specimen displacement ductility was *** results indicate that ductility decreases with axial pressure ratio increasing,and increases with stirrup reinforcement ratio *** values of axial pressure ratio and minimum stirrup reinforcement ratio of columns are proposed to satisfy definite ductility *** suggested values provide a reference for eng.neering application and for the amendment of the current Chinese design code of steel reinforced concrete composite structures.

关键词：建筑结构建筑物抗震设计混凝土结构

Vectorial Bed load Equations and River Width Dynamic Adjustment Modeling

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四川大学学报（工程科学版） 2005年第S1期37卷 124-127页

作者： Shi, Bing Cao, Shuyou Liu, Xingnian Yang, Kejun Lab. of Hydraulics and Mountain River eng. Sichuan Univ. Chengdu 610065 China School of eng. Ocean Univ. of China Qingdao 266071 China

Based on the analysis of forces acting on non-cohesive sediment particle under non-equilibrium con- dition,a vectorial equation of coarse particle movement on arbitrarily riverbed and the mathematical model used to simulate river width adjust are developed,some flume experiments for the time evolution of straight river channel are done.

关键词： sediment transport vectorial equation river width adjustment

Research on Secure Authentication Mechanism of Grid

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Journal of Donghua University(eng.ish Edition) 2005年第4期22卷 94-97页

作者：张龙军陈克非赵怀勋 Dept. of Computer Sci. and eng. Shanghai Jiaotong University Shanghai 200030 Dept. of Communicate eng. Eng. College of Armed Police Force Xi'an 710086

Based on the analysis on the security mechanism of grid, this paper discusses the advantages of latest techniques of grid security, and presents a secure authentication scheme of grid based on elliptic curve cryptosys... 详细信息

关键词： Grid GT3 ECC.