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Damage and progressive failure of concrete structures using non-local peridynamic modeling

Science china(Technological sciences) 2011年第3期54卷 591-596页

作者： HUANG Dan1,2. ZHANG Qing1,2.& QIAO PiZhong1,3.1 state {3. {2. of Hydrology-water Resources and Hydraulic engineering, Hohai university, Nanjing 2.0098, china 2.Department of engineering Mechanics, Hohai university, Nanjing 2.0098, china 3.Department of Civil and Environmental engineering, Washington state university, Pullman, WA 99164-2.10, USA 1. state key {2. of Hydrology-{3. Resources and Hydraulic engineering Hohai University Nanjing 210098 China2. Department of Engineering Mechanics Hohai University Nanjing 210098 China3. Department of Civil and Environmental Engineering Washington State University Pullman WA 99164-2910 USA

Peridynamics (PD), a recently developed theory of solid mechanics, which employs a non-local model of force interaction and makes use of integral formulation rather than the spatial partial differential equations used in the classical continuum mechanics theory, has shown effectiveness and promise in solving discontinuous problems at both macro and micro scales. In this paper, the peridynamics theory is used to analyze damage and progressive failure of concrete structures. A non-local peridynamic model for a rectangular concrete plate is developed, and a central pairwise force function is introduced to describe the interior interactions between particles within some definite distance. Damage initiation, evolution and crack propagation in the concrete model subject to in-plane uni-axial tension, in-plane uni-axial compression and out-of-plane impact load are investigated respectively. The numerical results show that discontinuities appear and grow spontaneously as part of the solution to the peridynamic equations of motion, and no special failure criteria or re-meshing techniques are required, which proves the potential of peridynamic modeling as a promising technique for analyzing the progressive failure of concrete materials and structures.

关键词： concrete damage progressive failure peridynamic model discontinuities

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Experiments and sensitivity analyses for heat transfer in a meter-scale regularly fractured granite model with water flow

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Journal of Zhejiang university-Science A(Applied Physics & engineering) 2012年第12期13卷 958-968页

作者： Wei LU1,2.Yan-yong XIANG1 (1School of Civil engineering,Beijing Jiaotong university,Beijing 100044,{2.) (2.3. key laboratory of Simulation and Regulation of water Cycle in River Basin,{2. Institute of water Resources and hydropower Research,Beijing 10003.,{2.) 1. School of Civil engineering Beijing Jiaotong University Beijing 100044 China 2. state key {2. of Simulation and Regulation of water Cycle in River Basin China Institute of Water Resources and Hydropower Research Beijing 100038 China

Experiments of saturated water flow and heat transfer were conducted for a meter-scale model of regularly fractured granite. The fractured rock model （height 1502.5 ram, width 904 mm, and thickness 3.0 mm）, embedded with two vertical and two horizontal fractures of pre-set apertures, was constructed using 18 pieces of intact granite. The granite was taken from a site currently being investigated for a high-level nuclear waste repository in china. The experiments involved different heat source temperatures and vertical water fluxes in the embedded fractures either open or filled with sand. A finite difference scheme and computer code for calculation of water flow and heat transfer in regularly fractured rocks was developed, verified against both the experimental data and calculations from the TOUGH2.code, and employed for parametric sensitivity analyses. The experiments revealed that, among other things, the temperature distribution was influenced by water flow in the fractures, especially the water flow in the vertical fracture adjacent to the heat source, and that the heat conduction between the neighboring rock blocks in the model with sand-filled fractures was enhanced by the sand, with larger range of influence of the heat source and longer time for approaching asymptotic steady-state than those of the model with open fractures. The temperatures from the experiments were in general slightly smaller than those from the numerical calculations, probably due to the fact that a certain amount of outward heat transfer at the model perimeter was unavoidable in the experiments. The parametric sensitivity analyses indicated that the tem- perature distribution was highly sensitive to water flow in the fractures, and the water temperature in the vertical fracture adjacent to the heat source was rather insensitive to water flow in other fractures.

关键词： Fractured granite water flow Heat transfer Physical modeling Numerical calculation Sensitivity analysis

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In situ experiments on width and evolution characteristics of excavation damaged zone in deeply buried tunnels

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Science china(Technological sciences) 2011年第S1期54卷 167-174页

作者： LI ShaoJun 1,FENG XiaTing 1,LI ZhanHai 3.CHEN BingRui 1,JIANG Quan 1,WU ShiYong 2.HU Bin 2.&XU JinSong 2.1 {3. key {2. of Geomechanics and Geotechinical engineering,Institute of Rock and Soil Mechanics,Chinese Academy of sciences,wuhan 43.071,china 2.Ertan hydropower Development Company,Ltd.,Chengdu 610051,china 3.School of Resources and Civil engineering,Northeastern university,Shenyang 110004,china 1. state key {2. of Geomechanics and Geotechinical {3. Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China3. School of Resources and Civil Engineering Northeastern University Shenyang 110004 China2. Ertan Hydropower Development Company Ltd. Chengdu 610051 China

The seven long tunnels of Jinping II hydropower station are deeply *** width and evolution characteristics of excavation damaged zone(EDZ) are the key problem to the design of tunnels excavation and *** order to study this problem,several specific experimental tunnels with different overburden and geometric sizes were excavated at this *** borehole camera,sliding micrometer,cross-hole acoustic wave equipment and acoustic emission apparatus were *** paper introduced the comprehensive in situ experimental methods through pre-installed facilities and pre-drilled *** properties of the surrounding rock mass,including cracks,deformation,elastic wave and micro fractures,were measured during the whole process of the tunnel *** width and characteristics of formation and evolution of tunnels EDZ were analyzed under different construction methods involving of TBM and drilling and blasting,the test tunnels were excavated by full-face or two *** relationships between EDZ and tunnel geometry sizes,overburden and excavation method were described as *** results will not only contribute a great deal to the analysis of rock mass behavior in deeply buried rock mass,but also provide direct data for support design and rockburst prediction.

关键词： deeply buried tunnel excavation damaged zone evolution characteristics in situ experiments

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The reflection of regular and irregular waves by a partially perforated caisson breakwater on a step bed

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Acta Oceanologica Sinica 2009年第4期28卷 107-117页

作者： LIU Yong LIYucheng TENG Bin XIA Zhisheng key laboratory of Ocean {2. Ocean {3. of china Qingdao 266100 China state key {2. of Coastal and Offshore {3. Dalian University of Technology Dalian 116024 China key laboratory of {2. ＆ {2. ＆ Sediment Science and {2. Hazard Prevention Changsha 410076 China

This study examines the reflection of regular and irregular waves from a partially perforated caisson breakwater located on a step bed. The step bed is treated as an idealized rubble mound foundation. Based on the linear potential theory, an analytical solution is developed to calculate the reflection coefficient of the structure subjected to regular waves. The matched eigenfunction expansion method is used for the solution. The regular wave method is also extended to irregular waves using a linear transfer function. The calculated results obtained for limiting cases are exactly the same as corresponding results given by the previous researchers. The present predictions also agree well with experimental data in the published literatures. Numerical experiments are conducted to examine the variations of the reflection coefficient versus its main effect factors, and some interesting results are presented.

关键词： partially perforated caisson step irregular waves reflection coefficient

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Soil erosion and sediment transport in the gullied Loess Plateau:Scale effects and their mechanisms

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Science china(Technological sciences) 2009年第5期52卷 1283-1292页

作者： LI TieJian1,WANG GuangQian1,XUE Hai2.3.& WANG Kai4 1 state key {2. of Hydroscience and engineering,Tsinghua university,Beijing 100084,china 2.Yellow River engineering Consulting Co.,Ltd.,Zhengzhou 450003.china 3.North china Institute of water Conservancy and hydropower,Zhengzhou 450008,china 4 china Institute of water Resources and hydropower Research,Beijing 10003.,china 1. state key {2. of Hydroscience and {3. Tsinghua University Beijing 100084 China 2. Yellow River engineering Consulting Co. Ltd. Zhengzhou 450003 China 3. North china Institute of water Conservancy and {2. Zhengzhou 450008 China 4. china Institute of water Resources and {2. Research Beijing 100038 China

Scale effects exist in the whole process of rainfall-3.runoff-3.soil erosion-3.sediment transport in river basins. The differences of hydrographs and sediment graphs in different positions in a river basin are treated as basic scale effects, which are more complex in the gullied Loess Plateau, a region notorious for high intensity soil erosion and hyper-concentrated sediment-laden flow. The up-scaling method of direct extrapolation that maintains dynamical mechanism effective in large scale application was chosen as the methodology of this paper. Firstly, scale effects of hydrographs and sediment graphs were analyzed by using field data, and key sub-processes and their mechanisms contributing to scale effects were clearly defined. Then, the Digital Yellow River Model that integrates sub-models for the subprocesses was used with high resolution to simulate rainfall-3.runoff-3.soil erosion-3.sediment transport response in Chabagou watershed, and the distributed results representing scale effects were obtained. Finally, analysis on the simulation results was carried out. It was shown that gravitational erosion and hyper-concentrated flow contribute most to the spatial variation of hydrographs and sediment graphs in the spatial scale. Different spatial scale distributions and superposition of different sub-processes are the mechanisms of scale effects.

关键词： scale effect soil erosion hyper-concentrated sediment-laden flow the Loess Plateau

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Run off-on-out method and models for soil infiltrability on hill-slope under rainfall conditions

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Science china Earth sciences 2006年第2期49卷 193-201页

作者： LEI Tingwu1,2. LIU Han1, PAN Yinghua3. ZHAO Jun2. ZHAO Shiwei2.& YANG Yonghui2.1. The key laboratory of Modern Precision Agriculture System Integration Research, College of Hydraulic and Civil Engineer-ing, {2. Agricultural university, Beijing 100083. {2. 2. state key laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and {13. Conservation, Yangling 712.00, {2. 3. Geographic and Resources Management College, Yantai Normal university, Yantai 2.402., {2. 1. The key laboratory of Modern Precision Agriculture System Integration Research College of Hydraulic and Civil Engineering China Agricultural University Beijing 100083 China 2. state key {2. of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water Conservation Yangling 712100 China 3. Geographic and Resources Management College Yantai Normal University Yantai 264025 China

The soil infiltrability of hill-slope is important to such studies andpractices as hydrological process, crop water supply, irrigation practices, and soil erosion. A newmethod for measuring soil infiltrability on hill-slope under rainfall condition with run off-on-outwas advanced. Based on water (mass) balance, the mathematic models for soil infiltrability estimatedfrom the advances of runoff on soil surface and the water running out of the slope were *** of {3.cases were conducted. Case Ⅰ was done under a rainfall intensity of {3. mm/h, at aslope gradient of about 0° with a runoff/on length (area) ratio of 1 : 1. Case Ⅱ was under arainfall intensity of 60 mm/h and a slope of {3.° with a runoff/on length (area) ratio of 1 : *** ring method was also used to measure the infiltrability for comparison purposes. Theexperiments were done with soil moisture of 10%. Required data were collected from laboratoryexperiments. The infiltrability curves were computed from the experimental data. The resultsindicate that the method can well conceptually represent the transient infiltrability process, withcapability to simulate the very high initial soil infiltrability. The rationalities of the methodand the models were validated. The errors of the method for the two cases were 1.8{3./1.3.% and4.49%/3.5{3.% (Experimental/Model) respectively, as estimated by comparing the rainfall amount withthe infiltrated volume, to demonstrate the accuracy of the method. The transient and steadyinfiltrability measured with double ring was much lower than those with this new method, due towater supply limit and soil aggregates breaking down at initial infiltration stage. The method canovercome the short backs of the traditional sprinkler method and double ring method for soilinfil-traility. It can be used to measure the infiltrability of sloped surface underrainfall-runoff-erosion conditions, in the related studies.

关键词： Infiltrability, runoff-on-out, rainfall, sloped surface, model.

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LARGE EDDY SIMULATION OF OPEN CHANNEL FLOWS WITH NONSUBMERGED VEGETATION

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Journal of Hydrodynamics 2011年第2期23卷 258-264页

作者： HUAI Wen-xin WU Zhen-lei QIAN Zhong-dong GENG Chuan state key {2. of {3. Resources and hydropower engineering Science Wuhan University Wuhan 430072 China

Results of several Large Eddy Simulations （LES） this article. It is shown that the vegetation can make the flow of open channel flows with non-submerged vegetation are presented in structure in the mainstream direction uniform for both supercritical and subcritical flows. For subcritical flows, the LES results of the ensemble-average of time-averaged velocity distributions at four vertical sections around a single plant are in good agreement with measurements. The velocity sees double peaks at the upper and lower positions of flows. For supercritical flows, the ensemble-average velocities see some discrepancy between LES and measurement results. Some secondary flow eddies appear near the single plant, and they just locate in the positions of the double peaks in stream-wise velocity profiles. It is also found that the vegetation drag coefficient deceases as the Froude number increases.

关键词： non-submerged sub/supercritical flow peak value Large Eddy Simulation (LES) secondary flow drag coefficient

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STOCHASTIC ANALYSIS OF GROUNDwater FLOW SUBJECT TO RANDOM BOUNDARY CONDITIONS

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Journal of Hydrodynamics 2008年第5期20卷 553-560页

作者： SHI Liang-sheng YANG Jin-zhong CAI Shu-ying LIN Lin state key {2. of {3. Resources and hydropower engineering Science Wuhan University Wuhan 430072 China

A stochastic model was developed to simulate the flow in heterogeneous media subject to random boundary conditions. Approximate partial differential equations were derived based on the Karhunen-Loeve （KL） expansion and perturbation expansion. The effect of random boundary conditions on the two-dimensional flow was examined. It is shown that the proposed stochastic model is efficient to include the random boundary conditions. The random boundaries lead to the increase of head variance and velocity variance. The influence of the random boundary conditions on head uncertainty is exerted over the whole simulated region, while the randomness of the boundary conditions leads to the increase of the velocity variance in the vicinity of boundaries.

关键词： groundwater flow Karhunen-Loeve (KL) expansion hydraulic head random boundary variance

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CHARACTERIZATION AND CAUSATION OF RUNOFF AND SEDIMENT VARIATION IN THE JIALINGJIANG RIVER BASIN

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International Journal of Sediment Research 2007年第3期22卷 228-237页

作者： Quanxi XU1,2. Songsheng CHEN3. Ming XIONG4, Shengwei LI5, and Zefang CHEN6 1 Senior engineer, Bureau of Hydrology, Changjiang water Resources Commission(CWRC), wuhan 43.010, {2.2.state key laboratory of water Resources and hydropower engineering Science, wuhan university, wuhan, {2., {12. 3.4 Prof., Bureau of Hydrology, CWRC, wuhan, {2. 43.010. 5,6 Engineer, Bureau of Hydrology, CWRC, wuhan, {2. 43.010. CWRC Bur Hydrol Wuhan 430010 Peoples R China wuhan Univ State Key Lab Water Resources & Hydropower Engn S Wuhan 430072 Peoples R China

The Jialingjiang River basin is one of the main sediment contributing areas in the upper reaches of the Changjiang River. Great changes have taken place in the runoff and sediment discharge in recent years. Comparing the data of 1991-2.03.with the data of 1954-1990, the annual runoff of the Jialingjiang River basin decreased by 2. %, and the suspended sediment transport decreased by 74% or 105 million tons. The main factors affecting the reduction include a decrease in rainfall, sediment detention of hydraulic structures, soil and water conservation activities, sedimentation and sand dredging in the river channel. Thorough investigation and analysis of the contribution of each factor to the sediment decrease at Beibei Station was determined for the first time. The following are the contributing percentages for each factor: a decrease in runoff accounted for 3.0}9%; soil and water conservation measures accounted for 16.4%; sediment detention of hydraulic structures accounted for 3..5%; sedimentation, river channel sand dredging, and other factors accounted for 2..2.. These findings are very important for forecasting the trend of inflow sediment discharge variation.

关键词： Jialingjiang River basin Variation in characteristic of runoff and sediment Quantitative analysis on contribution of influence factors

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GATE REGULATION SPEED AND TRANSITION PROCESS OF UNSTEADY FLOW IN CHANNEL

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Journal of Hydrodynamics 2008年第2期20卷 231-238页

作者： TAN Guang-ming DING Zhi-liang WANG Chang-de YAO Xiong state key {2. of {3. Resources and hydropower engineering Science Wuhan University Wuhan 430072 China

The operation methods of channel and the speed of gate regulation have great influence on the transformation of flow in water conveyance channels. Based on characteristics method, a 1-D unsteady flow numerical model for gate regulation was established in this study. The process of water flow was simulated under different boundary conditions. The influence of gate regulation speed and channel operation methods on flow transition process was analyzed. The numerical results show that under the same conditions, with increasing regulation speed of the gate, the change rates of discharge and water level increase, while the response time of channel becomes shorter, and ultimately the discharge and water level will transit to the same equilibrium states. Moreover, the flow is easier to reach stable state, if the water level in front of the sluice is kept constant, instead of,behind the sluice. This study will be important to the scheme design of automatic operation control in water conveyance channels.

关键词： check gate regulation speed unsteady flow transition process numerical simulation

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