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THE ROLE FORE AIR FLOW IN SOIL SLOPE STABILITY ANALYSIS

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Journal of Hydrodynamics 2009年第5期21卷 640-646页

作者： ZHANG Xiao-yue ZHU Yue-ming FANG Chun-hui college of water conservancy and hydropower Engineering Hohai University Nanjing 210098 China

In order to investigate the effect of the pore air flow in the soil slope stability analysis, a water-air two-phase flow model, based on the multi-phase flow theory, is proposed and with the model, the water-phase and air-phase seepages of the soil slope in the stable seepage and rainfall situations are simulated. The soil slope safety coefficients are obtained according to the simulated pore air pressure and pore water pressure. The calculation results show that in the stable seepage situation, the influence of the pore air pressure on the soil slope stability can be neglected, while in the rainfall situation, the pore air pressure generated in the unsaturated zone will reduce the safety coefficient, and the larger the distance between the slip surface and the underground water level is, the greater the influence of the pore air pressure on the soil slope stability will be.

关键词： unsaturated soil water-air two-phase flow rainfall slope stability

Effects of Bahia Grass Cover and Mulch on Runoff and Sediment Yield of Sloping Red Soil in Southern china

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Pedosphere 2011年第2期21卷 238-243页

作者： LI Xin-Hu ZHANG Zhan-Yu YANG Jie ZHANG Guo-Hua WANG Bin college of water conservancy and hydropower Engineering Hohai University Nanjing 210098 (China) Key Laboratory of Efficient Irrigation-Drainage and Agricultural Soil hohai university Nanjing 210098 (China) Jiangxi Institute of Soil and water Conservation Nanchan9 330029 (China) china Irrigation and Drainage Development Center Beijing 100054 (China) college of water conservancy and Building Engineering Northeast Agricultural University Harbin 150030 (China)

Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on sloping red soil in southern *** runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive *** contrast,the bare plot (C) had both the highest surface runoff coefficient and the highest sediment *** were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among *** runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot *** of Bahia grass cover were excellent,indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region.

关键词： groundwater runoff interflow lysimeter soil properties surface runoff

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土石坝震害与抗震安全

水力发电学报 2011年第6期30卷 40-51页

作者：朱晟河海大学水文水资源与水利水电工程科学国家重点实验室南京210098 河海大学水电学院南京210098

结合世界上地震区已建土石坝的震害调查,对主要震害型式、产生机理以及防止震害的对策进行了剖析,分析了现代碾压式高土石坝抗震性能优良的内在原因。从设防标准、抗震能力与抗震风险以及坝体填筑设计质量控制指标等方面论证了现阶段强... 详细信息

结合世界上地震区已建土石坝的震害调查,对主要震害型式、产生机理以及防止震害的对策进行了剖析,分析了现代碾压式高土石坝抗震性能优良的内在原因。从设防标准、抗震能力与抗震风险以及坝体填筑设计质量控制指标等方面论证了现阶段强震区高土石坝建设需重视的问题。在深入开展土石坝抗震理论研究的基础上,适当提高坝料填筑设计指标以控制有害变形,强震区300m级高土石坝的建设是安全可行的。

关键词：地震土石坝液化滑坡永久变形

ON NECESSITY OF PLACING AN AERATOR IN THE BOTTOM DISCHARGE TUNNEL AT THE LONGTAN hydropower STATION

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Journal of Hydrodynamics 2006年第6期18卷 698-701页

作者： WU Jian-hua WU Wei-wei RUAN Shi-ping college of water conservancy and hydropower Engineering Hohai University Nanjing 210098 China

The air entrainment for avoiding cavitation damage has been widely used in long free flow tunnels. It is crucial to determine whether an aerator is needed for shorter tunnels. In this article, the bottom discharge tunnel at the Longtan hydropower Station was involved, for which the free flow tunnel section was only 50.00 m long. The cavitation in the tunnel with and without the aerator was investigated using the physical models of the scale 1/30, through the measurements of cavitation noise. The experimental results show that it is necessary to place the aerator at the inlet of the free flow section for higher reservoir level to protect this tunnel from cavitation damage.

关键词： aerator bottom discharge tunnel cavitation damage cavitation noise Longtan hydropower Station

AN IMPROVED PTV SYSTEM FOR LARGE-SCALE PHYSICAL RIVER MODEL

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Journal of Hydrodynamics 2008年第6期20卷 669-678页

作者： TANG Hong-wu CHEN Cheng CHEN Hong HUANG Jian-tong college of water conservancy and hydropower Engineering Hohai University Nanjing 210098 China

To measure the surface flow in a physical river model, an improved system of Large-Scale Particle Tracking Velocimetry （LSPTV） was proposed and the elements of the PTV system were described. Usually the tracer particles of a PTV system seeded on water surface tend to form conglomerates due to surface tension of water. In addition, they can not float on water surface when water flow is shallow. Ellipsoid particles were used to avoid the above problems. Another important issue is particle recognition. In order to eliminate the influence of noise, particles were recognized by the processing of multi-frame images. The kernel of the improved PTV system is the algorithm for particle tracking. A new 3-frame PTV algorithm was developed. The performance of this algorithm was compared with the conventional 4-frame PTV algorithm and 2-frame PTV algorithm by means of computer simulation using synthetically generated images. The results show that the new 3-frame PTV algorithm can recover more velocity vectors and have lower relative error. In addition, in order to attain the whole flow field from individual flow fields, the method of stitching individual flow fields by obvious marks was worked out. Then the improved PTV system was applied to the measurement of surface flow field in Model Yellow River and shows good performance.

关键词： Large-Scale Particle Tracking Velocimetry (LSPTV) particle 3-frame PTV physical fiver model

Study on embedded length of piles for slope reinforced with one row of piles

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Journal of Rock Mechanics and Geotechnical Engineering 2011年第2期3卷 167-178页

作者： Shikou Yang, Xuhua Ren, Jixun Zhang college of water conservancy and hydropower Engineering, hohai university, nanjing, 2.0098, china college of water conservancy and hydropower Engineering Hohai University Nanjing 210098 China

The embedded length of anti-slide piles for slope is analyzed by three-dimensional elastoplastic shear strength reduction method. The effect of embedded pile length on the factor of safety and pile behavior is analyzed. Furthermore, the effects of pile spacing, pile head conditions, pile bending stiffness and soil properties on length and behavior of pile are also analyzed. The results show that the pile spacing and the pile head conditions have significant influences on the critical embedded length of pile. It is found that the critical embedded length of pile, beyond which the factor of safety does not increase, increases with the decrease in pile spacing. The smaller the pile spacing is, the larger the integrity of the reinforced slope will be. A theoretical analysis of the slip surface is also conducted, and the slip surface determined by the pressure on piles, considering the influences of both soil and piles for slope, is in agreement with the ones in previous studies.

关键词： slope stability factor of safety embedded pile length strength reduction method slip surface

Computational theory of cavitating flows for hydraulic turbomachinery with consideration of influence of water quality

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Science china(Technological Sciences) 2010年第12期53卷 3341-3348页

作者： WANG Lei1,2 & CHANG JinShi2 1 Huadian Electric Power Research Institute, Hangzhou 310030, china 2 college of water conservancy and Civil Engineering, china Agricultural university, Beijing 100083, china Huadian Electric Power Research Institute Hangzhou China college of water conservancy and Civil Engineering China Agricultural University Beijing China

Previously it was assumed that the pressure within the cavity or on the cavity surface remained constant and the vapor pressure of clean water at 20°C and 0 m altitude was utilized as the computational boundary for cavitating flows in hydraulic turbomachinery. Cavitation was confused with vaporization, and the effect of water quality on cavitation pressure characteristics was not taken into account. In recent years, lots of experiments of cavitation pressure characteristics of different water qualities including different sand concentrations of sand water and different altitudes of clean water have been performed by the authors, and the important influences of water quality on cavitation pressure characteristic have been validated. Thus the water quality should be involved in the cavitating flows computation. In the present paper, the effect of water quality on the cavitation pressure characteristic is analyzed and the computational method and theory of cavitating flows for hydraulic turbomachinery that considers the influence of water quality are proposed. The theory is suitable for both the potential flow method and the two-phase flow method for cavitating flows simulation. Finally, the validation results for cavitating flows in a hydraulic tur- bine indicate the significant influences of water quality on the cavitating flow performance.

关键词： cavitating flows cavitation pressure water quality hydraulic turbomachinery

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强震作用下高拱坝损伤开裂研究

水力发电学报 2011年第6期30卷 143-147页

作者：程恒张燎军河海大学水利水电学院

本文基于混凝土的力学特性,建立能够反映混凝土动态情况的多轴损伤开裂模型。以等效三维一致粘弹性边界反映远域地基辐射阻尼效应,采用Mohr-Coulomb材料模型模拟坝基裂隙岩体在地震作用下的力学行为,运用非线性地震波动分析方法研究国... 详细信息

本文基于混凝土的力学特性,建立能够反映混凝土动态情况的多轴损伤开裂模型。以等效三维一致粘弹性边界反映远域地基辐射阻尼效应,采用Mohr-Coulomb材料模型模拟坝基裂隙岩体在地震作用下的力学行为,运用非线性地震波动分析方法研究国内某拱坝在强震作用下的损伤开裂过程。通过对大坝的损伤程度以及坝体上、下游面的最大拉应力进行分析,给出大坝的抗震薄弱部位,并对其抗震安全性进行了评价。研究揭示拱坝动力损伤灾变机理,为高拱坝抗震安全评价提供一种分析途径。

关键词：水工结构损伤开裂拱坝强震非线性

Integrating MODFLOW and GIS technologies for assessing impacts of irrigation management and groundwater use in the Hetao Irrigation District,Yellow River basin

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Science china(Technological Sciences) 2009年第11期52卷 3257-3263页

作者： XU Xu1,2, HUANG GuanHua1,2 & QU ZhongYi3 1 Center for Agriculture water Research, china Agricultural university, Beijing 100083, china 2 Chinese-Israeli International Center for Research and Training in Agriculture, china Agricultural university, Beijing 100083, china 3 water conservancy and Civil Engineering college, Inner Mongolia Agricultural university, Hohhot 010018, china Center for Agriculture water Research China Agricultural University Beijing China Chinese-Israeli International Center for Research and Training in Agriculture China Agricultural University Beijing China water conservancy and Civil Engineering college Inner Mongolia Agricultural University Hohhot China

Due to severe water scarcity, water resources used in agricultural sector have been reduced markedly in Hetao irrigation district. Application of water-saving practices (WSPs) is required for the sustainable agricultural development. The human activities including WSPs and increase of groundwater abstraction can lower down the groundwater table, which is helpful to the salinity control. Meanwhile, an excessively large groundwater table depth may result in negative impact on crop growth and fragile ecological environment. In this paper, the Jiefangzha irrigation system in Hetao irrigation district was selected as a typical area, a groundwater flow model based on ArcInfo Geographic Information System (GIS) was developed and implemented to quantify the effect of human activities on the groundwater system in this area. The preand post-processing of model data was performed efficiently by using the available GIS tools. The time-variant data in boundary conditions was further edited in Microsoft Excel with programs of Visual Basic for Application (VBA). The model was calibrated and validated with independent data sets. Application of the model indicated that it can well describe the effect of human activities on groundwater dynamics in Jiefangzha irrigation system.

关键词： groundwater flow modeling MODFLOW GIS water-saving practices irrigation district