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July 30,2011
Volume 4,Issue 14
Pages -
Subject Area:Hydraulic Structures,Basic Subject of Hydraulic Engineering,Environmental Water Conservancy,Basic Subject of Civil and Architectural Engineering, Engineering Mathematics, Engineering Mechanics,Foundation Engineering,Civil and Architectural Engineering Design

Title: Impact factors of irrigation water use efficiency of well-canal combined irrigation district, case from Liuyuankou irrigation district

Authors: DUAN Zhongde, TAN Fang, CUI Yuanlai, LIU Luguang
PP: 1334-1339
Abstract: Based on the data of Liuyuankou irrigation district from 1985 to 2000, the irrigation water use efficiency (IWUE) was calculated with the net irrigation water use and gross irrigation water use. According to the IWUE and impact factors of different years, the impact laws and degree of different factors which affect the IWUE were investigated with principal component analysis. The results showed that area of irrigation, water diversion ratio base on well and capital input in Liuyuankou irrigation district have greater positive contribution rate to the IWUE, and groundwater level has greater negative contribution rate. IWUE of well irrigation is higher than that of canal irrigation.
Keywords: water resources and hydropower engineering； irrigation water use efficiency; impact factors; principal component analysis

Title: Seismic damage simulation of concrete gravity dam

Authors: WANG Nali, ZHONG Hong
PP: 1326-1333
Abstract: Based on macro homogeneous assumption, this paper considered local vulnerable area s microscopic heterogeneity, used the damage evolution model with power function decline and residual strength, and applied maximum tensile stress criterion and Moore coulomb standard as damage judgment s threshold value, and then studied concrete gravity dam s seismic damage through ANSYS secondary development. Stress compare of Koyna in three material characteristics showed the necessity of considering concrete s microscopic heterogeneity and non linear; The compare of Koyna s simulation results with tensile damage only and tensile compression damage showed that cracking of concrete dam are mainly due to tensile failure, and the heel and head is seismic weak positions, which should be strengthened in the design.
Keywords: hydraulic structure； concrete gravity dam; microscopic heterogeneity; damage; numerical simulation

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Title: Downscaling extreme precipitation in Dongjiang River Basin of China based on SDSM

Authors: WANG Peng, RONG Yanshu, WANG Wen, WEI Lusi
PP: 1312-1320
Abstract: In this paper, a statistical downscaling model was built in Dongjiang River Basin of China based on statistical down scaling model (SDSM) method by using the observed daily precipitation data from China Meteorological Centre, daily reanalysis data from the National Center for Environmental Prediction and the National Center for Atmospheric Research (NCEP/NCAR), and output data of scenarios A2 and B2 of the HadCM3 model from the Hadley Centre for Climate Prediction and Research. The explaining variances of SDSM model for Dongjiang River Basin are close to or exceed SDSM models for other regions' simulation and the SDSM model for Dongjiang River Basin is capable of reproducing various statistical characteristics. The results of simulation for Dongjiang River Basin show that the simulation of annual precipitation is best, the simulation of maximum daily precipitation is worse. In the future of 2011~2099, there is a decrease trend in annual precipitation both in A2 and B2 scenario.
Keywords: hydrology and water resources；annual precipitation; extreme precipitation; statistical down scaling model； future scenarios； Dongjiang River Basin of China

Title: Research development and prospect of agricultural non-point source pollution

Authors: LI Ruihong, HONG Lin, ZHU Wenyuan
PP: 1304-1311
Abstract: The research development of agricultural non-point source pollution at home and abroad were reviewed and summarized in this paper, the theoretic researches, modeling methodologies and control techniques were studied, and the research development in non-point pollution research was prospected. Through analyses of the main problems currently exiting in the study of agricultural non-point source pollution, the research directions of non-point source pollution were put forward: improvement of theoretical research systems through combining multi-discipline and intensifying migration rules research of non-point source pollution, construction of practical models through integrating ‘3S’ techniques and uncertainty research of simulation, and strengthening the control technology study of both engineering and management.
Keywords: environment hydro-science; agricultural; reviews; non-point source pollution; research dynamic; existing problems; development trend

Title: Study of construction standard in local regions and sustainable development of Shanghai urban construction

Authors: CHEN Shiming
PP: 1299-1303
Abstract: Construction codes and specifications are standards and unified technique rules which should be followed and guided in construction practice. In the paper, drafting and codification work as well as the features of recent Shanghai construction standards are summarized and analyzed. Suggestions are proposed to formalize the constructive frame of Shanghai construction standard and to be capable of sustainable development of Shanghai urban construction.
Keywords: engineering construction; engineering construction standard; standard system; sustainable development

Title: Influence of using channel expansion modules and lengthening pressure cell cables on calibration of pressure cells

Authors: HU Chenchen, ZHANG Peng, QIAN Kai
PP: 1293-1298
Abstract: The chief object of this research is to survey the influence of using channel expansion module（CEM） and lengthening pressure cell cables on the calibration of resistance strain pressure cells. The results show that the pressure cells' initial values change when a CEM is connected to the DT515, however , slopes of calibration curves almost remain the same; the influence of the extended cables on the calibration of pressure cells is so faintness that can be ignored; all the pressure cells remain the fine linearity of the calibration curves of which the correlation coefficients R2 are approximately 0.99.
Keywords: geotechnical engineering；resistance strain pressure cell; channel expansion module; calibration

Title: Verification and parameter determination of three-dimensional Duncan-Chang model

Authors: FU Haiyan, ZHU Jungao
PP: 1289-1292
Abstract: In this paper, the three-dimensional Duncan-Chang model is analyzed and verified. The results of triaxial consolidated drained test for soil are used to verify the model. The relationship between the parameters for the three dimensional Duncan-Chang's model and those for the original Duncan-Chang's model are analyzed. A reasonable method for determining the parameters for the three dimensional Duncan-Chang model is presented.
Keywords: geotechnical engineering； Duncan-Chang model; triaxial test; parameter determination

Title: Study of BP neural network model of cyclic behavior of super-elastic shape memory alloy

Authors: REN Wenjie, JIA Ru, HAN Lei
PP: 1283-1288
Abstract: In this study, the cyclic tensile tests were carried out on the super-elastic shape memory alloy (SMA) wires. According to the testing data, a constitutive model for the cyclic behavior of super elastic SMA was put forward based on back propagation (BP) neural network. In this model, the inputs included the number of loading cycles, the index of loading and unloading and the strain; and the output was the stress. 25 experimental curves were used for training the neural network and 5 curves for testing the neural network. Simulations indicated that the model had a high accuracy of predictions. The model ran simply, and the training and test data can be acquired easily. This study provides a new method for developing the cyclic constitutive model of super-elastic SMA.
Keywords: disaster prevention and reduction engineering; shape memory alloy; super-elasticity; back-propagation neural network; constitutive model

Title: Study on the image detection technology of the hollowing rate of the building exterior wall based on Matlab

Authors: ZHANG Jing, QU Juntong, DONG Jiagang, JU Duanjun, WANG Junhong
PP: 1275-1282
Abstract: The experiment model of debond defect of building detected by infrared thermograph is set up, and polystyrene foam is used instead of the hollowing within the external walls of buildings. The obtained images of them are analyzed to calculate the ratio of the empty swell by digital image processing technique, and the final consequence is compared with the experimental design value. It is shown that Matlab is liable to the ratio of the hollowing of the buildings facing tiles and can provide basis for maintaining and processing the internal hidden danger and examining the security of the facing tiles.
Keywords: wall project; ceramic tile in the external wall; infrared thermograph; image processing; Matlab

Title: Numerical simulation of uniaxial compression strength for recycled concrete

Authors: CHENG Juan, PENG Yijiang, DANG Nana
PP: 1269-1274
Abstract: In order to study strength and failure mechanism of recycled concrete, the recycled concrete is taken as a non-uniform five-phase composites consisting of natural aggregate, old cement mortar, new cement mortar, old bond zone and new bond zone on meso-level. According to Walraven formula, the number of representative aggregate particles is determined. The meso-scale structure is represented with random aggregate model by using Monte-Carlo method. Double broken line damage model is adopted to describe the meso-element's damage devolution. The propagation processes of cracks of recycled concrete in uniaxial compression test are simulated using finite element method. The stress-strain curve and compressive strength of recycled concrete are gained.
Keywords: structural engineering; recycled concrete; meso-level; random aggregate model; uniaxial compression; strength

Title: Research on fan base and road design of coastal beach wind power station

Authors: XIAO Jingjing
PP: 1264-1268
Abstract: Beach wind field geology and topography are often complicated, so selection of fan base pile type and bearing stratum of pile end is very important. In this paper, combined with the previous engineering experience of wind field and geological conditions, scheme comparison was performed and a more reasonable and economic design was selected. Beach wind field at the road design are also an important factors influencing engineering cost. This paper summarizes the design of the road aiming at the beach wind field characteristics and provides reference for similar wind farm design.
Keywords: structural engineering; beach wind power; fan base; pit road; design optimization

Title: Numerical simulation analysis of shaft excavation of Baiji Mine

Authors: YANG Yan, SHAO Peng, LIU Xia, YANG Dabing, REN Guangxue, FAN Zhiyu
PP: 1258-1263
Abstract: The three level main and auxiliary shafts of Baiji Mine of Lianyungang Coal Industry Company are all throughout shafts. Its excavation sequence is first the main shaft and then the auxiliary shaft. There are a great number of faults and rock joints, so the surrounding rock between -760 m m and -660 m are seriously broken. For studying the affects of main shaft stability which influenced by auxiliary shaft excavation in these broken rock mass, this paper uses the FLAC3D software to analyze the change rule of the displacement field and the stress field of main shaft s surrounding rock when excavating the auxiliary shaft. The results show that the excavation of auxiliary shaft would cause great influence on the stability of main shaft s surrounding rock. This paper comes up with this influence law providing quantitative basis for support design and construction.
Keywords: numerical simulation； FLAC3D； main and auxiliary shaft； excavation effect； displacement field； stress field

Title: Test method research on cradle of continuous beam bridge

Authors: FENG Zhongren, HUA Xianding, WANG Qi
PP: 1253-1257
Abstract: Combined with the example on the cradle test of the (40+64+40) meter continuous beam of Lufeng double track big bridge in Guangtong Kunming Railway Engineering in Yunnan, the result of preload test was analyzed and compared with structure theory. The results showed that by the use of normal prestressed reinforcement of zero block to preload the cradle by jack is simple, safe and highly applicable.
Keywords: bridge engineering；continuous beam; cantilever construction; cradle test

Title: Evaluation method of pre stress loss of cables in cable-strut joints of suspend domes during pre-tension process

Authors: LIU Huijuan, LUO Yongfeng, YANG Lvfeng
PP: 1248-1252
Abstract: Calculating the pre-stress loss of cables in cable-strut joints accurately is a crucial step of construction control for suspend-domes. In order to study the pre-stress loss caused by friction of cable-strut joints, characteristics of cable-strut joints are investigated in this paper, and the pre-stress losing mechanism during pre-tension is investigated. Using the porthole friction theory in pre-stressed concrete structures, combined with the characteristics of the cable-strut joints, a formula for evaluating the pre-stress loss in cable strut joints of the suspend-domes is developed. Then adopting the formula, the pre-stress loss of an actual suspend-dome is evaluated and the results show that the method is correct and effective.
Keywords: construction mechanics；suspend-dome; pre-stress tension; pre-stress loss; friction of joints; loading mechanism

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