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钢纤维几何尺寸对钢纤维混凝土损伤变形特性的影响

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土木工程学报 2010年第4期43卷 119-124页

作者：康亚明刘长武韩小刚王东四川大学水利水电学院四川成都610065 四川大学水力学与山区河流开发保护国家重点实验室四川成都610065

钢纤维混凝土是在普通混凝土中均匀掺入一定量钢纤维而组成的一种多相复合材料。利用空间应力状态下的损伤统计本构方程,得出了钢纤维掺量和钢纤维几何尺寸不同时的分布参数和临界损伤值,并定性分析了钢纤维掺量和钢纤维几何尺寸对损伤... 详细信息

钢纤维混凝土是在普通混凝土中均匀掺入一定量钢纤维而组成的一种多相复合材料。利用空间应力状态下的损伤统计本构方程,得出了钢纤维掺量和钢纤维几何尺寸不同时的分布参数和临界损伤值,并定性分析了钢纤维掺量和钢纤维几何尺寸对损伤变形参数的影响。研究结果表明:(1)钢纤维的掺入显著降低了混凝土的脆性,提高了混凝土的宏观平均强度;(2.分布参数m能综合反映钢纤维混凝土的脆性;其倒数1/m可以反映其延性,即反映钢纤维的增韧作用;(3)分布参数ε*可以综合反映钢纤维混凝土的宏观平均强度,即可以综合反映钢纤维的增强作用;(4)钢纤维的几何尺寸(如长度、长细比)对钢纤维的增强和增韧作用有显著影响。

关键词：钢纤维混凝土几何尺寸变形特性 Weibull分布临界损伤分布参数韧性

EFFECT OF DISCHARGE RATIO ON FLOW CHARACTERISTICS IN 90°EQUAL-WIDTH OPEN-CHANNEL JUNCTION

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Journal of Hydrodynamics 2009年第4期21卷 541-549页

作者： ZHANG Ting XU Wei-lin WU Chao College of Civil engineering Fuzhou University Fuzhou 350108 China state key {2. of hydraulics and mountain river engineering Sichuan University Chengdu 610065 China

For the 90° equal-width open-channel junction flow, the Reynolds averaged Navier-Stokes equations are solved while using the 3-D κ- ω model. The mean flow pattern and the secondary current are obtained. The model is validated by experimental data, and then applied to investigate the effect of the discharge ratio on the shape of separation zone shape, the cross-sectional mean flow angle and the contraction coefficient. The results are fairly close to those of the prior studies. The numerical modeling is both less time-consuming and less expensive to obtain the various flow parameters needed for engineering design.

关键词： κ- ω turbulent model open-channel junction separation zone secondary current

Theoretical analysis and experiment of micromechanics and mechanics-optics coupling of distributed optic-fiber crack sensing

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中国科学：技术科学英文版 2011年第S1期54卷 185-191页

作者： LIU HaoWu 1,2.CHEN Jiang 2.SUN Man 3 & DING Rui 2.1 state key {2. of hydraulics and mountain river engineering,sichuan university,chengdu 610065,china 2.School of Water Resource Hydropower,sichuan university,chengdu 610065,china 3 School Electrical engineering and Information,sichuan university,chengdu 610065,china sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Peoples R China sichuan Univ Sch Water Resource Hydropower Chengdu 610065 Peoples R China sichuan Univ Sch Elect Engn & Informat Chengdu 610065 Peoples R China

The micromechanical behaviors and mechanics-optics coupling effects of optic-fiber-concrete complex in the distributed optic-fiber sensing concrete-crack technology,which was used in health monitoring of Wu Gorge Bridge on Yangtze river and a large dam successfully,have been investigated.A micromechanical theoretical analysis method and micromechanical frictional contact bi-interface model,as well as a modified optical theoretical analysis method of the mechanics-optics coupling effects are presented.A series of verification experiments,including mechanical experiments and mechanics-optics coupling experiments,have been *** results of micromechanical theoretical analysis and the analysis of the modified theory of mechanics-optics coupling along with mechanical and optical experimental data are shown to be in close *** the micromechanical theory and the modified theory of mechanics-optics coupling with their analysis methods can not only enhance credibility of this novel distributed sensing technology but also provide a way to understand its sensing mechanism and optimize its technical details and system.

关键词： optic-fiber sensing mechanics-optics coupling micromechanics health monitoring concrete structure crack detection

A new type of plunge pool―Multi-horizontal submerged jets

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Science china(Technological Sciences) 2008年第12期51卷 2128-2141页

作者： DENG Jun,XU WeiLin,ZHANG JianMing,QU JinXue & YANG YongQuan state key {2. of hydraulics and mountain river engineering,sichuan university,chengdu 610065,china state key {2. of hydraulics and mountain river engineering Sichuan University Chengdu 610065 China

Based on the understanding of the mechanism of energy dissipation,a new type of plunge pool is presented with the advantages of high rate of energy dissipation,low impact pressure,and small close-to-bed velocity on the soleplate of the plunge *** first advantage owes to enlarged shearing energy dissipation areas in the plunge pool,while the other two are caused by the jet that enters in a nearly horizontal level to keep the soleplate from being scoured *** of the above arrangements make this new type of energy dissipator distinct from the underflow energy *** experiments on the physical model,the authors found that the water flow maintained stable and submerged in horizontal direction when the flow was narrow in horizontal but thick in vertical ***,the wide flat nappe was ready to submerge or float as the downstream water level rised or *** entire flow fields of multi-horizontal submerged jets into plunge pool were also numerically *** numerical results of water surface curve,close-to-bed velocity and floor pressure agree well with the experimental *** flow pattern in the plunge pool was analyzed after combining the laboratory data and numerical simulation.

关键词： hydraulic engineering 3-D flow field numerical simulation plunge pool submerged jets

Study on bed load transport for uniform sediment in laminar flow

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Science china(Technological Sciences) 2010年第9期53卷 2414-2422页

作者： YANG FengGuang,LIU XingNian,CAO ShuYou,YANG KeJun & HUANG Er state key {2. of hydraulics and mountain river engineering,sichuan university,chengdu 610065,china 1. state key {2. of hydraulics and mountain river engineering Sichuan University Chengdu 610065 China

Previous studies focused on the bed load transport rate for the condition of turbulent flow,while the knowledge of sediment transport in laminar flow is very *** an extreme case to reflect the viscous effect on sediment transport,sediment transport in laminar flow is considered in this *** are at least two factors affecting the transport rate of sediment under laminar flow conditions: (1) fluid forces;(2. particle to particle ***,these two factors represent the physical transport ***,an exposure degree Probability Density Function (PDF) is developed to explore how the transport rate can be associated with characteristics of laminar flow and this factor reflects the particle to particle interactions,and the pickup probability equation in the absence of turbulence is developed based on the stochastic approach which reflects the exposure degree ***,the formulas to calculate the critical shear stress of incipient motion and the bed load transport rate of fine uniform sediment are *** derivation is made mainly based on Einstein’s bed load theory;we choose Einstein’s equation to model this system because we believe that the probabilistic approach taken is an appropriate way to account for the spatial and temporal variations in the forces causing sediment *** formulas have been tested against a wide range of existing laboratory data and compared with other existing empirical or semiempirical *** predictions by these newly proposed formulas are very good.

关键词： exposure degree bed load transport rate pickup probability laminar flow shear stress

CHARACTERISTIC ANALYSIS OF THE PLUNGING OF TURBIDITY CURRENTS

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Journal of Hydrodynamics 2010年第2期22卷 274-282页

作者： AN Rui-dong LI Jia state key {2. of hydraulics and mountain river engineering Sichuan University Chengdu 610065China College of Water Recourse and Hydropower Sichuan University Chengdu 610065 China

Turbidity currents are flows driven by suspended sediment of flood-induced turbid river water with excess *** currents are often the governing factor in reservoir sedimentation by transporting fine materials over long distances and delivering the majority of deposition,which thus reduces the storage ***,the design and operation of a reservoir requires an accurate prediction of its occurrence condition and plunging position,which is the objective of the present *** article presents a verified algebraic slip mixture model including momentum,continuity and algebraic velocity expressions to simulate 2.D turbidity *** experiments in a multiphase flume were carried *** number,sediment concentration and densimetric Froude number were used as parameters in the occurrence condition *** plunging of turbidity currents may produce reflux and backflow due to the diving flow at the surface of the clear *** similar experimental results were also obtained by PIV measurements

关键词： turbidity current plunge suspend sediment algebraic slip mixture model densimetric Froude number

INTERACTION OF A CAVITATION BUBBLE AND AN AIR BUBBLE WITH A RIGID BOUNDARY

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Journal of Hydrodynamics 2010年第4期22卷 503-512页

作者： XU Wei-lin BAI Li-xin ZHANG Fa-xing state key {2. of hydraulics and mountain river engineering Sichuan University Chengdu 610065 China Institute of Acoustics Chinese Academy of Sciences Beijing 100190 China

The motion of a spark-induced cavitation bubble and an air bubble near a rigid boundary is experimentally studied by using high-speed *** dimensionless parameters are used to describe the geometrical configuration of the bubble-bubble-boundary *** bubble-bubble interaction can be considered in two different *** cavitation bubble will collapse towards the air bubble if the air bubble is relatively small,and away from the air bubble if the air bubble is relatively *** two zones are identified in the bubble-boundary interaction,and they are the danger zone and the safety *** relative position,the bubble-boundary distance and the bubble-bubble distance play important roles in the bubble-bubble-boundary interaction,which can be considered in several conditions according to the responses of the *** jets are found to penetrate into the cavitation *** cavitation bubble and the air bubble（air jet） move in their own way without *** motion of a cavitation bubble may be influenced by an air bubble and/or a rigid *** influence of the air bubble and the influence of the boundary may be combined,like some thing of a vector.

关键词： cavitation bubble air bubble rigid boundary collapse

Spatial-temporal effects of temperature control device of stoplog intake for JinpingⅠhydropower station

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Science china(Technological Sciences) 2011年第S1期54卷 83-88页

作者： DENG Yun,TUO YouCai ,LI Jia,LI KeFeng & LI Ran state key {2. of Hydraulic & mountain river engineering,sichuan university,chengdu 610065,china 1. state key {2. of Hydraulic & mountain river engineering Sichuan University Chengdu 610065 China

This article presents an analysis of the spatial-temporal effect of multi-level stoplog gate intake adopted at Jinping I hydropower station,which is to reduce the adverse impacts on fish breeding caused by cold water discharged from the station in spring and summer.A mathematical model is applied to predict the temperature distribution in reservoir and outflow temperature process of the downstream of Jinping I station with two different types of intake-low level single intake and multi-level stoplog gate *** a single station,the latter shows great improvement over the former on temperature distortion(suitable for fish breeding) .In order to evaluate the cumulative effect for different intake types,the analysis is extended to include the next four hydropower stations *** results show that the outflow temperature of stoplog intake is more close to the nature condition comparing with the low level intake for the Jinping I hydropower *** the side effect of cold water in April during temperature raising period can be well improved,but no obvious effect in *** I hydropower station has dominated influence on temperature process at lower reach of Yalong *** by the downstream hydropower station cascade,cold temperature effect in spring and summer seems to be cumulatively enhanced,but the heating effect turns weakened during *** analysis suggests the improving effect of stoplog intake can maintain 80%at estuary in April,which clearly shows that stratified intake scheme used in control station can mitigate the cold temperature effect in spring and summer for the whole river basin.

关键词： temperature stratification stoplog gate intake temperature control cascade power stations mathematical model

Bed Load Transport Rate in Scouring and Armoring Process of Non-uniform Sediment river Bed

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四川大学学报（工程科学版） 2005年第S1期37卷 86-88页

作者： LI Wenping CAO Shuyou LIU Xingnian(state key Lab.of {2. and mountain river Eng.,sichuan Univ.,chengdu 610065,china) state key Lab. of {2. and mountain river Eng. Sichuan Univ. Chengdu 610065 China

Flume experiments were carried out to study bed load transport rate during rive bed scouring and ar- moring.A theoretical differential equation linking the transport rate to the probability of incipient motion of non-uniform sediment is *** transport rate is shown to decrease exponentially with time,according to the theory,which is in good agreement with the experiment data.

关键词： bed-load scouring and armoring sediment transport rate