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NUMERICAL MODELLING OF ROCK FALL USING EXTENDED DDA

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岩石力学与工程学报 2003年第6期22卷 926-931页

作者： Chen Guangqi (Graduate school of civil and Structural engineering, Kyushu University, Fukuoka 816-8581 Japan) Graduate school of civil and Structural engineering Kyushu University 日本 Fukuoka

The reasonable design of protective structures to mitigate the hazards from rock fall depends on the knowledge of motion behaviors of falling stones,such as the falling paths,velocities,jump heights and *** simulation is an effective way to gain such kind of knowledge,In this paper,the discontinuous deformation analysis (DDA) is applied to rock fall *** order to obtain more reliable results,the following improvements and extensions are made on the original DDA.(1)Solve the problem of block expansions due to rigid body rotation error.(2) Add the function of modeling the drag resistance from air and plants so that the velocities of falling stones obtained by simulations are good enough in agreement with those by experiments in situ.(3)Add the capability to consider energy loss due to block collisions so that the jumping heights and distances obtained by simulations are good enough in agreement with thos by experiments even for the slope with very soft layer on its *** of application examples is presented to show that the extended DDA is very effective and useful in rock fall ***,the presented method is expected to be put into wide use in slop stability analysis.

关键词：岩石力学 DDA 落石运动岩石力学能量损耗 DDA 边坡

Mechanism of zonal disintegration in surrounding rock mass around deep rock engineering and its application

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Science China(Technological Sciences) 2011年第S1期54卷 221-227页

作者： ZHANG YongXing & ZHANG BoHu school of civil engineering,Chongqing University,Chongqing 400045,China school of civil engineering Chongqing University

The mechanical behaviors of deep rock mass are different from those of shallow rock *** cases of Jinping II Hydropower Station,the special phenomenon of zonal disintegration in the surrounding rock mass around the diversion tunnels,is *** the basis of fracture mechanics,a new strength criterion for deep rock mass is *** new nonlinear strength criterion that is relative to the rock mass rating classification can be applied to the study of the tensile failure of deep rock ***,zonal disintegration model is established,and the radius of fractured zone and none-fractured zone of deep surrounding rock mass around cylindrical tunnel are obtained,their exact positions and the evolution law of zonal disintegration of surrounding rock mass is *** validate the present model,comparison between calculation results and the experiment observation on facture and failure around underground openings is carried *** is found that the numerical simulation result is in good agreement with the experimental one on failure modes around the *** sensitivity analysis,the effects of stress condition,cohesion and the angle of internal friction on the phenomenon of zonal disintegration are ***,the present model is adopted in the analysis of the zonal disintegration in the surrounding rock mass around the diversion tunnels in Jinping II Hydropower ***,the magnitude and distributions of fractured zones are determined by numerical simulation.

关键词： deep rock mass zonal disintegration strength criteria of deep rock mass numerical simulation

On time-step in structural seismic response analysis under ground displacement/acceleration

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Earthquake engineering and engineering Vibration 2009年第3期8卷 341-347页

作者： TianYuji~+ and Yang Qingshan~(++) school of civil engineering,Beijing Jiaotong University,Beijing 100044,China +Associate Professor ++Professor school of civil engineering Beijing Jiaotong University Beijing 100044 China

There are two models in use today to analyze structural responses when subjected to earthquake ground motions, the Displacement Input Model （DIM） and the Acceleration Input Model （AIM）. The time steps used in direct integration methods for these models are analyzed to examine the suitability of DIM. Numerical results are presented and show that the time-step for DIM is about the same as for AIM, and achieves the same accuracy. This is contrary to previous research that reported that there are several sources of numerical errors associated with the direct application of earthquake displacement loading, and a very small time step is required to define the displacement record and to integrate the dynamic equilibrium equation. It is shown in this paper that DIM is as accurate and suitable as, if not more than, AIM for analyzing the response of a structure to uniformly distributed and spatially varying ground motions.

关键词： integration time step multi-supported structure displacement input model acceleration input model spatially varying ground motions

Contact position controlling for two-dimensional motion bodies by the boundary element method

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Journal of University of Science and Technology Beijing 2002年第2期9卷 138-141页

作者： Junping Pu and Yuanfeng Wang school of civil engineering and Architecture, Northern Jiaotong University, Beijing 100044, China school of civil engineering and Architecture Northern Jiaotong University Beijing 100044 China

An algorithm is presented for controlling two-dimensional motion contact bodies with conforming discretization. Since a kind of special boundary element is utilized in the algorithm, the displacement compatibility and traction equilibrium conditions at nodes can be satisfied simultaneously in arbitrary locations of the contact interface. In addition, a method is also proposed in which the contact boundary location can be moved flexibly on the possible contact boundary. This method is effective to deal with moving and rolling contact problems on a possible larger moving or rolling contact region. Numerical examples show effectiveness of the presented scheme.

关键词： boundary element method contact move roll

Remote collaborative pseudo-dynamic testing system based on acquisition board control

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Progress in Natural Science:Materials International 2007年第12期17卷 1487-1493页

作者： Wang Dapeng and Tian Shizhu(school of civil engineering, Harbin Institute of Technology, Harbin 150090, China) school of civil engineering Harbin Institute of Technology Harbin 150090 China

In this paper, NetSLab network platform for remote collaborative pseudo-dynamic testing, which was developed recently by a research group led by the Hunan University, is presented. Aiming at MTS system which is widely used in structural testing, the control method with acquisition board was investigated in this study to realize the communication interface between NetSLab and MTS system, and open up the remote collaborative pseudo-dynamic testing system. Using the developed testing system, a collaborative pseudo-dynamic testing on LAN was carried out successfully. The result manifests that the data transmission and collaborative control can be implemented accurately between NetSLab and MTS system, so that the usability of the testing system is validated.

关键词： remote sharing of testing equipment network platform communication interface acquisition board control collaborative pseudo-dynamic testing.

A new framework for evaluating along-wind responses of a transmission tower

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Earthquake engineering and engineering Vibration 2009年第1期8卷 87-93页

作者： Liu Guohuan and Li Hongnan school of civil and Hydraulic engineering, Dalian University of Technology, Dalian 116023, China PhD Professor school of civil and Hydraulic engineering Dalian University of Technology Dalian 116023 China

In this paper, an analytical framework to evaluate the along-wind-induced dynamic responses of a transmission tower is presented. Two analytical models and a new method are developed：（1） a higher mode generalized force spectrum （GFS） model of the transmission tower is deduced; （2） an analytical model that includes the contributions of the higher modes is further derived as a rational algebraic formula to estimate the structural displacement response; and （3） a new approach, applying load with displacement （ALD） instead of force, to solve the internal force of transmission tower is given. Unlike conventional methods, the ALD method can avoid calculating equivalent static wind loads （ESWLs）. Finally, a transmission tower structure is used as a numerical example to verify the feasibility and accuracy of the ALD method.

关键词： along-wind-induced dynamic responses transmission tower generalized force spectrum equivalent static wind loads

A new seismic isolation system and its feasibility study

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Earthquake engineering and engineering Vibration 2010年第1期9卷 75-82页

作者： Jia Gaofeng~+ and Shi Zhifei~(++) school of civil engineering,Beijing Jiaotong University,Beijing 100044,China Graduated Student ++ Professor school of civil engineering Beijing Jiaotong University Beijing 100044 China

This paper introduces a new seismic isolation system called a periodic foundation （PF）, where inclusions are periodically arranged. The PF is different from traditional base isolation in that it causes a fundamental frequency shift in the structure, thus reducing its response and generating a frequency gap. If the frequency contents of a seismic wave fall into the gap, it can not propagate in the foundation. Thus, it will exert no influence on the structure above. A systematic study of the band of frequency gap for a 2D PF is conducted. The influence of physical and geometrical parameters such as density and elastic modulus as well as filling fraction of the PF and its materials on the band of frequency gap are investigated, and a design with a frequency gap as low as 2.49-3.72 Hz is achieved. This band of frequency gap corresponds well to the design spectra in earthquake engineering. Numerical simulations of a six-story frame structure with different foundations demonstrate that a proposed PF can greatly reduce the seismic response of an isolated structure. This investigation shows that PFs have great potential in future applications of seismic isolation technology.

关键词： seismic isolation periodic foundation band of frequency gap

An approach to 3D NURBS modeling of complex fault network considering its historic tectonics

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Progress in Natural Science:Materials International 2006年第5期16卷 546-553页

作者： ZHONG Denghua, LIU Jie and LI Mingchao (school of civil engineering, Tianjin University, Tianjin 300072, China) school of civil engineering Tianjin University Tianjin 300072 China

Fault disposal is a research area that presents difficulties in 3D geological modeling and visualization. In this paper, we propose an integrated approach to reconstructing a complex fault network (CFN). Based on the non-uniform rational B-spline (NURBS) techniques, fault surface was constructed, reflecting the regulation of its spatial tendency, and correlative surfaces were enclosed to form a fault body model. Based on these models and considering their historic tectonics, a method was put forward to settle the 3D modeling problem when the intersection of two faults in CFN induced the change of their relative positions. First, according to the relationships of intersection obtained from geological interpretation, we introduced the topological sort to determine the order of fault body construction and rebuilt fault bodies in terms of the order; then, with the disposal method of two intersectant faults in 3D modeling and applying the Boolean operation, we investigated the characteristic of faults at the intersectant part. An example of its application in hydropower engineering project was proposed. Its results show that this modeling approach can increase the computing efficiency while less computer memory is required, and it can also factually and objectively reproduce the CFN in the engineering region, which establishes a theoretical basis for 3D modeling and analysis of complex engineering geology.

关键词： fault network NURBS technique historic tectonics topological sort 3D modeling.

Study on multi-scheme analysis and evaluation method for concrete sequence placement of high arch dam

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Science China(Technological Sciences) 2011年第S1期54卷 47-53页

作者： ZHONG GuiLiang,REN BingYu & TONG DaWei Department of Hydraulic and Hydroelectric engineering,school of civil engineering,Tianjin University,Tianjin 300072,China Department of Hydraulic and Hydroelectric engineering School of Civil Engineering Tianjin University

A complete scheme for solving the key scientific problems of how to make concrete sequence placement scheme of high arch dam reasonable and feasible and how to meet the need of construction process was ***,based on a coupling analysis of concrete sequence placement system of high arch dam,a mathematical model considering complex construction constraints was ***,a multi-scheme computational analysis method for concrete sequence placement of high arch dam was proposed based on dynamic ***,a multi-scheme evaluation method for concrete sequence placement was put forward based on analytic hierarchy ***,feedback guidance for progress control and management in the high arch dam construction process was ***,these methods were applied to a practical project to show that the methods can analyze and evaluate multi-scheme for concrete sequence placement of high arch dam effectively,optimize the process of dam concrete sequence placement,and recommend engineering *** methods provide new theoretical principles and technical measures for real-time progress control in the high arch dam construction.

关键词： sequence placement analysis multi-scheme evaluation dynamic simulation analytic hierarchy process high arch dam construction