The Fenhe Ｒeservoir has many functions such as water supply,irrigation,flood control and ecological regulation． It is of great significance to study the emergency environment events of the reservoir． Two-dimensional hydrodynamic combined with reservoir water quality coupling model,the reservoir measured data is adopted to model calibration and verification．The impact of event sources,considered discharge entrances and winds,study the diffusion and concentration distribution of pollutants under different scenarios． The results show that the wind direction determines the diffusion path of pollutants,wind speed determines the rate of pollutant diffusion,diffusion area and excessive area of pollutants with wind speed approximately obey a linear relationship; The discharge range of pollutants at each outlet is the largest in the east, and the inlet at the north upper reaches is larger than the inlet in the western Jianhe． Establishing emergency prediction table can deal with sudden pollution incident in Fenhe Ｒeservoir．

Under the framework of total factor water use efficiency measurement,the super-efficiency SBM-Undesirable model considering undesired outputs is deployed to measure the water use efficiency of Guangxi＇s planting industry under chemical fertilizer pollution emission constraints． On this basis,preliminary explorations are made on the spatial-temporal pattern evolution laws and features of planting industry water use efficiency by using an exploratory spatial data analysis method ( ESDA) ． Ｒesearch results indicate that: from 2011 to 2015,the water use efficiency of Guangxi ＇ s planting industry under pollution emission constraints was not high on the whole,and only Nanning, Fangchenggang and Chongzuo reached an effective frontier and formed“a situation of tripartite confrontation”． During the study period,the water use efficiency of Guangxi ＇ s planting industry under pollution emission constraints showed a significant positive global space autocorrelation,but its spatial spillover effect weakened year by year． There is relatively few changes in the spatial correlation types of planting industry water use efficiency in different cities,and more than half of the cities in Guangxi stably have low-low agglomeration areas; and the high -high agglomeration areas presents a three -core hotspot agglomeration model consisting of Nanning,Fangchenggang and Chongzuo

In order to analysis the characteristics and driving factors of meteorological factors in the past 50 years in the Northwest China, the daily meteorological data from 69 stations in the Northwest China from 1966 to 2016 were used to quantify using the Mann-Kendall test, Morlet wavelet analysis, GIS inverse distance weighted interpolation spatial analysis and correlation analysis methods.The temporal and spatial variation of meteorological factors and their interactions were analyzed.The results showed that the wind speed, radiation, and relative humidity all showed a downward trend in the past 50 years with a decrease of 0.105m/(s·10a), 0.054MJ/(m2·d·10a) and 0.378%/10a respectively, precipitation and temperatures showed an overall upward trend with an increase of 4.9mm/10a and 0.427°C/10a.The meteorological factors have shown periodic "increasing-decreasing" oscillations and the main cycle of the changes is 28 years, and there are local mutations in the wind speed, radiation, relative humidity, annual precipitation, and air temperature during the study period. There are regional differences in the spatial distribution of meteorological factors, the wind speed showed a discontinuous trend in the eastern part of the west, and the radiation showed a smaller distribution trend in the eastern and western parts of the country, the precipitation decreased from the southeast to the northwest, and the temperature showed outward expansion from Qinghai province.There are strong correlations between various meteorological factors and the impact relationship is complex, among which there is a very significant positive correlation between radiation and wind speed, precipitation and temperature (P<0.01), and there is a very significant negative correlation between relative humidity and wind speed (P< 0.01).

The hydrogen and oxygen isotopic are used to carry out a detailed investigation of the characteristics of spatial isotopic variation in the oasis of Pishan Ｒiver,which is located in the southern margin of the Tarim Basin,and to understand the interrelations of different water bodies in the same area． The hydrogen and oxygen isotopic compositions of all the samples are analyzed and by combining them with isotopic data obtained from previous research achievements and the precipitation in Hotan from 1988 to 1992,published by the global network of isotopes in precipitation ( GNIP) ,the previous research results have also been used for reference． It is fiound that: the annual precipitation isotope values in the study area have obvious seasonal differences,which can be roughly divided into two parts,the first part is from April to October,the precipitation isotopes in this part are relatively enriched and secondary from December to March,and the precipitation isotopes are relatively poor． In the same time period,each water body receives from different months of rainfall and ice snow recharge,the distributions of surface water and groundwater are similar,and the relationship between water bodies is close． For the rivers which are mainly recharged by glacial melting water,snow melting water and precipitation in the southern Xinjiang,the isotopic differences between the water bodies caused by recharge should be fully considered when the stable isotopes of D and 18O are used to distinguish the relationship between surface water and surface water．

Although Global Precipitation Measurement (GPM) mission provides finer spatial resolution as the latest satellite precipitation products, yet some systematic deviations and random errors still exist in GPM (IMERG) in different regions affected by various natural factors such as terrain, climate and so on. Aimed at improving the performance of the IMERG, this research, taking Weihe River as a typical area, selects the available gauge observation from April 1st, 2014 to December 31st, 2015 as reference, diverts the SM2RAIN-CCI obtained from the inversion of the satellite soil moisture via SM2RAIN algorithm, and employs an approach of the Weighted Least Square Estimation. Then the comparison and assessment of the fusion data and original IMERG have been accomplished against the gauge observation at daily scale. The results show as follow: (1) in the light of the station scale, compared to IMERG, the CC and RMSE of the fusion data has obviously been improved especially for the mid and low latitudes despite of the slight improvement in the BIAS; (2) fusion data can succeed in reducing statistical errors effectively at the mean daily precipitation of the basin; (3) the statistical metrics of the fusion data performs much better than original IMERG in spatial distribution over the basin.

SDOIF ( step duration orographic intensification factor method) has been recommended as a useful rainstorm separation method for the probable maximum precipitation ( PMP) estimation in mountainous areas． In order to investigate the variation of orographic intensification factors ( OIF) with different categories of extreme rainfall in mountainous areas as well as the uncertainties of the SDOIF,based on Hong Kong＇s historical 24h annual maximum precipitation data of 71 stations,the Ｒegional L-moments analysis is used to estimate the quantiles of different return periods ( 100-year,200-year,500-year) at 71 rainfall stations． Then Hong Kong＇s average OIF calculated based on the annual maximum precipitation and the quantiles of different return period are compared． The results show that by using the quantiles of 100- year return period to estimate the OIF is more stable and reasonable in spatial distribution． In addition,the study indicates that the selection of basic rainfall stations will affect the outcome of the OIF stimates to some extent,therefore adequate data and cautious investigation are required in the application of the SDOIF method．

In order to solve the problem of information insufficiency and redundancy in the screening of runoff forecast factors, this paper introduces a new method for correlation analysis— the maximum information coefficient (MIC) method, which is universal. By combining the principal component analysis (PCA) method which has the ability of dimensionality reduction through eliminating redundant information, a new algorithm that couples maximum information coefficient and principal component analysis (MIC-PCA) is proposed. Taking the daily runoff forecast of Daluo Hydrologic Station in the Yalong River basin as an example, we compare the results produced by MIC-PCA and multiple other factor screening methods. Then the selected factor sets are input into the BP neural network to forecast daily runoff to verify the rationality of MIC-PCA. The results show that compared with the current method, this method can provide more scientific and effective input for the prediction model, thus improving the prediction accuracy of the model and this method is of theoretical significance to the study of hydrological forecast.

Based on the daily flow data of three stations in Raohe basin from 1952 to 2014,the coefficient of variation,interannual extemum ratio,the methods of Kendall trend test,anomaly percentage are adapted to study the variation characteristics of inter-annual and annual average runoff and the evolution law of high and low in Raohe basin.The results shows that the inter-annual variation and annual distribution of runoff of the main and branch rivers are similar,and the annual distribution of runoff of the Raohe basin is extremely non-uniform;the occurrence probability of low year is higher than high year and the interdecadal cycle change is about 20 years;the interannual runoff seriesof 3 gauging stations from 1952 to 2000 presents an increase trend,but shows a decreasing trend since 2000．The results can provide reference for the comprehensive utilization and development of water resources and water ecological protection in Raohe River Basin.

Abstract: The identification of homogeneous regions which consist of sites with identical regional frequency distribution is the foundation of regional L-moment precipitation analysis. But intersite dependence of data tends to affect the accuracy of Hosking-Wallis homogeneity test by decreasing the outcome of the test. This paper studied the relationship between intersite dependence, record length and distance of gauging sites using annual maximum precipitation series of 936 sites in Jiang Xi province. Associated with the definition of Hosking-Wallis homogeneity test and Monte Carlo experiments, the effectiveness of the test was analyzed in the presence of different degree and patterns of intersite dependence. Through generating cross-correlated data with normal Copula, a correction of Hosking-Wallis homogeneity test was proposed. The improvement of the corrected test was then demonstrated by a series of Monte Carlo experiments.

In order to clarify the groundwater occurrence and well formation law in rural hilly areas of Heilongjiang province, data collection and field investigation method was adopted to analysis the regional distribution, hydrogeological conditions, well type and depth in the hilly areas of Heilongjiang Province. The results indicated that, hilly area of Heilongjiang Province could be divided into Heilongjiang main river, Songhua river, Neniang river, Wusuli river and Suifen river. In every hilly area, when the groundwater burial and mining conditions were quaternary pore water in mountain valleys the water layer was shallow, low water rich-medium rich water and easy exploit , wells type was tube, the depth was 30~70m. The third fissure pore water area and the cretaceous pore fissure water zone were deep buried, rich in water- medium rich water, and quite different, wells type was tube, the depth was 80~120m. Basalt cave and fissure water area was not suitable for large area mining. the bedrock fissure water area was not suitable for well completion. The purpose of this paper was to provide some reference for drilling work in hilly areas of our province, through the analysis of groundwater occurrence and formation conditions.

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Integrated Design of Water Ｒesources Information Monitoring Management Platform Based on Data Core Technology

The nowcasting of severe convective weather is very challenging． With the development of weather radar,the advantage of its high temporal and spatial resolution has been used in the research on nowcasting． By using echo data of radar to get the optimal spatial correlation of the contiguous time,the moving vector sequence at different times． Based on that,linear objective forecasting is made to radar echo． SCE -UA is used to make the estimation of parameters of the relation between radar echo intensity and rainfall intensity to achieve the goal of rainfall forecasting． The results show that,the forecasting image by using radar echo optimal spatial correlation method is similar to the real image,which means that this method has a highly practical value． By using SCE-UA method to forecast the rainfall intensity of the next 60 minutes,and comparing the observe rainfall intensity,then an error analysis is made,it shows that,the forecast accuracy by using experienced parameters is higher than using Kalman filter method．

In order to promote the popularization and application of corn drip irrigation technology in Yellow River irrigation area of Ningxia, in view of the prominent problem of lacking relevant water and fertilizer integration system for popularization of large-scale corn field drip irrigation in Yellow River irrigation area of Ningxia, this research adopted small plot comparative test in large field to carry out the test and research on corn drip irrigation water and fertilizer integration system in bare land. On the basis of comprehensively analyzing soil moisture content variation, water consumption, crop yield and water production efficiency during corn growth period with different irrigation quantity and fertilization, this paper put forward the water and fertilizer integration irrigation and fertilization system, in which the drip irrigation quota was 225-450m3/hm2, the irrigation was carried out for 11 times, the irritation quota was 3600m3/hm2, and the pure fertilization quantity was 459kg/hm2 (where, N, P2O5 and K2O were respectively 255, 123 and 81kg/hm2) during the growth period of corn, and to fertilize at the middle period of irrigation time for ten times. The yield of corn field drip irrigation exceeded 17250kg/hm2, and the water production efficiency reached more than 2.80kg/m3 or above.

A quantitative analysis is made of spatio-temporal distribution and evolution of surface AET． PET in Tarim Ｒiver Basin is essential for evaluating the energy balance and water conditions,it provides a certain theoretical basis for the estimation of ecological water requirement． In this paper,the spatio -temporal characteristics and variation trend of actual evapotranspiration ( AET) and potential evapotranspiration ( PET) are studied by using MOD16 data products during 2000－2014 in the Tarim Basin,Xinjiang,China． The results show that: the accuracy of the MOD16－PET－data ( Ｒ2 = 0．81) can meet the requirements of statistical analysis,and can be used to examine the spatio-temporal distribution of surface ET． The average annual AET fluctuation range is 306．54 ～ 383．77 mm,with a mean value of 345．04 mm,the average annual PET fluctuation range is 1 551．97 ～ 1 744．85 mm,with a mean value of 1 641．52 mm． The big gap between AET and PET show that the land surface is drought in Tarim Ｒiver Basin． Furthermore,the monthly variation of AET and PET show a pattern that increases first then decreases,such a gap difference between AET and PET in summer indicates that the land surface is extreme dry． The mean AET and PET show an annular spatial distribution characteristics centering the Tarim Basin． AET increases with the distance from the center,while PET keeps an opposite trend． The spatial distribution of AET is higher,while PET is lower in the mountainous areas ( Tianshan,Altun,Kunlun,and Pamir) ． The spatial distribution of AET is lower and PET is higher in the oasis of the Tarim Basin． During 2000－2014,AET is in a decreasing trend,while PET is in an increasing trend,showing that the drought in Tarim Ｒiver Basin has been aggravated in the past 15 years．

In order to investigate the effects of different mulching methods on soil water characteristics and yield of jujube trees at different developmental stages under the condition of water bubbled-root canopy irrigation,the inadequate irrigation experiment was conducted on jujube trees in northern Shaanxi.The results showed that the relationship of soil water content after the irrigation of the main bubbled irrigation was:straw mulching(12.06%)>mulching(11.27%)>CK (10.36%).The soil moisture in the whole growth period The distribution of the average coefficient of variation in the vertical direction(0-30cm,30-60cm,60-100cm)between the treatments was low (0-30cm),middle height(30-60cm)and low(60-100cm).The results showed that the changes of soil water content under straw mulching were more stable and the water retention capacity was the best,while the mulching straw (0.407,0.336,0.304)<mulching(0.416,0.340,0.316)<CK (0.411,0.355,0.323);Covering conditions:The average growth rate of jujube hanging was: mulching(0.185)>CK(0.175)>straw mulching(0.160),and the surface temperature had a significant effect on the growth stage of jujube hanging;straw mulching was more effective than mulching and CK Increase by 29.32% and 39.40%.Straw covered moisture conservation measures are more suitable for mountain jujube trees in the loess plateau in northern Shaanxi,different straw mulch and cover thickness of the bubbled-root irrigation jujube tree water consumption will be the focus of the next step.

In the process of inducer design,this paper presents circulation distributions to regulate the blade angle at different blade heights． According to the design experience of axial pumps,a new type of inducer with nonlinear ring distribution is designed on the basis of prototype pump． The influence of nonlinear ring distribution on the performance of inducers is studied by numerical calculation． Hydraulic design calculation results show that the circulation distribution can be used as the control parameter for inducer design and they directly affects the wrap angle of the inducer． The numerical simulation results are as follows． Inducer with nonlinear circulation distribution has a significant effect on the cavitation performance of the pump,but it has a limited influence on the external characteristics of the pump．

Adjustable axial-flow pump hydraulic mechanical seal static ring seat spring seat structure after 2 vertical transformation of Jiangdu fourth pumping station, Jiangdu station in 2009 four after the overall transformation of the mechanical seal in the use of the existing spring loose, the problem of corrosion is difficult to replace, in 2012 through the spring seat shaft hole cut out of a corner, thereby increasing the spring seat the contact surface of the shaft hole method, solves the spring installation and maintenance is difficult to press questions. But many groups of off spring, corrosion phenomenon in actual use, will replace the stainless steel material on the basis of the calculated increase the length of the spring. By running the basic solution of.2013 shedding corrosion and other problems further improved, the spring by integrated into half, realize it is unnecessary to remove the static ring system can easily replace the spring effect, enhance the efficiency of dynamic and static ring mechanical seal. The operation of this test. The secondary transformation improves the efficiency and reliability of the mechanical seal of the water seal of the vertical fully adjustable axial flow pump, and provides a guarantee for the operation of the project, which has the advantages of simple structure, high reliability and low price.

In the arid regions of the North China, the contradiction between increasing water consumption and the limited water resources per capitais growing, especially in small towns. This paper employed the Yuzhou town of Yu County of Zhangjiakou Distict as an example, 18 residential communities were surveyed with 156 householdsamples. and surveyed the relationship between water consumed structure and resident income level. Itshowed that 1. The seasonal change of water supply quantity is strong, July is the highest, per capita about 1.96m3/days, February minimum, about 1.31m3/days. 2. The domestic water consumption and resident income level in a certain range to meet the quadraticfunction relationship (y=-0.26x2+3.79x-5.39,R2=0.94), that is, with the increase of income level of residents living water consumption increased and stabilized. 3. There is a general waste of water for residents and a large space for water conservation in the future. 4. Resident awareness of drinking water safety and water supply facilities have some hidden dangers, which need to be paid attention to in the future resident public safety education and town planning and construction.

In order to refine the original flood control rules of Longtan reservoir, combined with the characteristics of the diversification of the flood types, the classified flood control rules of Longtan reservoir were proposed. The optimization process of the rules was divided into three steps:1) Considering the operability and practicability, the forecast information of different orders of magnitude was included in the rules as the discriminant condition to construct the self-identification control method, and the classified flood control rules including the forecast variable and the control variable was established. 2) With the flood set weighted average peak cut taken as the optimization target, the forecast variable and the control variable were optimized by simulation. 3) The superiority of the classified flood control rules were tested using the different types of typical flood. The results show that the classified flood control rules can give full play to flood control benefits and improve the operation effect of different types of floods effectively, possessing strong practicality and operability.

: In order to analyze the risk zoning of mountain torrent disaster in Lushan scenic areas,based on the characteristics of mountainous torrent disasters in Lushan scenic areas,8 risk assessment factors are selected to set up the index system of mountainous torrent disasters according to the hazard and vulnerability of flood disastersThen,the weight of each factor is determined by analytic hierarchy process ( AHP) ． With the support of GIS technology,the zoning maps of danger,vulnerability and risk of mountainous torrent disasters are made, and the risk of the zone is deeply estimated． The results show that the high-risk areas of Lushan scenic areas are mainly distributed in the northwest of scenic area,including Xinglong Cableway,Shimen Gorge,Fairy Cave and Guling Park,etc．,which are regions full of tourists and essence of scenic spots while the low risk areas are mainly distributed in the northeast of scenic region．

Regional flood composition is the problem be solved in catchment development scheme design. In this paper, based on the flood data during 1951-2010 at Lutaizi and Zhongdu site, the two-parameter GH Copula function is chosen to construct the joint distribution of annual maximum 30d flood volumes at Lutaizi and Luzhong interval, taking tail dependence a full account. Contrastive analysis of flood distribution rationality at Zhongdu site in the light of four different methods which are conditional expectation composition, conditional most likely composition, most likely composition and equivalent frequency composition. Revealing the contribution rate of design flood of each region under different magnitude scenarios, regarding Lutaizi site as the boundary. For Zhongdu site, most likely composition should be chosen as design reference in the view of the safety of Hongze Lake and design rationality.

Based on the precipitation data of 15 meteorological stations in Anhui Province from 1965 to 2014,the precipitation anomaly percentage ( Pa) is used as the drought index,the temporal and spatial characteristics of Anhui Province are quantitatively analyzed from the annual and seasonal ( 3 months) time scales． The results show that: the drought in Anhui Province is unevenly distributed on the spatial scale,the drought frequency is high in the north and southwest,the frequency is lower in the middle and southeast,and the drought frequency decreases gradually from north to south． By comparing seasonal drought results,the autumn drought has the highest frequency,the highest intensity and the widest drought range,followed by summer droughts,winter droughts,and spring droughts． Spring droughts and autumn droughts have an aggravated trend,while the summer droughts and winter droughts are not obvious．

Based on the monthly precipitation data of 6 stations in Huangshui Basin from 1959 to 2016,the anomaly analysis method and Mann-Kendall test are used to analyze the characteristics of precipitation process changes in this basin,and the trend of future precipitation is analyzed combined with the method of Ｒ/ S． The drought characteristics and future drought trends are analyzed by using the run theory and Markov chain． The results show that the interannual variation of precipitation in this basin is more obvious． The precipitation in the whole year and the four seasons in the past 58 years shows an increasing trend,among which the increasing trend in winter is the most significant． The average annual precipitation is not uniform in the spatial distribution,the precipitation in the central region of the basin is the largest,and the precipitation in the downstream region is the smallest． The spatial distribution of Cv is similar to the average annual precipitation． Through the Hurst index,it can be seen that in the 1-year time scale,the annual precipitation in the river basin shows a strong continuous characteristic, showing strong persistent characteristics on the 5-year and 10-year time scales,and the annual precipitation in different time periods in the future． Precipitation may increase with seasons． According to the statistical results,the probability of continuous water in the river basin is greater than that of Lianfengshui,indicating that it is more prone to dry water． From the statistical results,the probability of continuous dry water is greater than that of continuous water,indicating that the phenomenon of continuous low water is more likely．

Cement soil has been widely used as a kind of ground treatment technology. However, there are relatively few studies on the tensile strength that affects the crack resistance of cement soil. In this paper, the antiseepage cushion of a hydropower station in Yili was studied by the uniaxial tensile test of cement soil. And the tensile strength of cement soil was compared with the tensile strength of unimproved soil. Additionally the effect of cement content and curing age on tensile strength and ultimate tensile strain of cement soil was investigated. and a formula for calculating the tensile strength of cement soil considering the amount of cement content and the curing age was proposed. Meanwhile, the infiltration test was carried out to study the infiltration characteristics of cement soil. Tests have found that the tensile strength of cement soil increases with the increase of cement content and growth of curing age. And the increase of tensile strength is obvious in 7d~14d. When the cement content is 10%, the tensile strength of cement soil increases rapidly with the increase of the cement content, when the cement content is more than 10%, the increment gradually decreases. And cement soil ultimate tensile strain varies in 1.6%~3.7%. In the meantime, conservation conditions have a great influence on the impermeability of cement soil.

In order to determine the filling and rolling parameters of the dam,the indoor test and the field rolling test are carried out． The physical properties of the filter material,the transition material and the rock-fill material are acquired through the indoor test． Meanwhile,the parameters such as the added water amount,the vibrant compaction and the paved thickness are obtained,and the test results are analyzed． Additionally,the corresponding quality control measures and recommendations are put forward,which can provide a reference for similar projects

For Fankou Pumping Station,the casting of ledger wall with commercial concrete has been arranged in January． Through the 3-D simulation analysis by using ANSYS finite element software,it has been found that the temperature stress in the construction period is excessive． Considering on the real process in construction site and a great number of calculation,presetting crack is recommended as the final plan． In the construction,this plan has been accepted,and what＇ s more,surface heat preservation has been tightened up． There is no temperature crack in the ledger wall through double-checking． The plan that presetting cracks in the ledger wall in cold periods are applicable to the similar projects

By analying and explaining the silt foundation of the sea dike with the method of the explosive compaction and sedimentation substitution,this paper explains the technical features and construction methods of the explosion squeeze and silt substitution method,and considers that the method of explosive compaction and sedimentation has the advantages of treating deep depth,large scope and fast construction progress． According to the theory of soil mechanics,the theoretical formulas of the depth D0 and the displacement depth d of the suspended structure are given． Finally,for example,the three reclamation projects of the swirl gate in this paper,the method of explosive compaction and replacement is introduced in detail,and the correlation radar geophysical prospecting is used to verify that the actual construction section is in accordance with the design section,and the shear strength index of the silt soil after the explosion treatment is generally reduced 0．8 ～ 0．9 times．

By analyzing the experiment data of the shear testing of composite interface directly supported shear and composite beams ( slabs) at home and abroad,it is found from the testing data that the shear capacity of the interface is not only related to the stirrup ratio,the roughness of interface and the strength of post-cast concrete,but also to the destroyed character of composite beam ( slab) ,the location change of the interface along the altitude of the beam ( slab) ,the ratio of shear span to effective depth of section and the secondary loading effect of shear stress,and so on． Based on analyzing synthetically the testing results and researches at home and abroad,the suggestions of calculated methods for shear capacity of the interface of composite beams ( slabs) and the corresponding conformation are put forward． The results may serve as a reference for revising the design code of concrete structure．

In this paper,based on the project of waterway revetment,by carrying out experiments insitu,characteristics of deformation and stress between U-mode reinforced concrete sheet pile and U-mode steel sheet pile are compared,and analyzing the law of displacement is analyzed． Ｒesults show that the distribution of soil pressure shows the law with big in the middle and small at both ends． There are significant differences between the results of soil pressure with standard calculation method and measured values． After filling behind the sheet pile, stress in the tension zone of sheet pile increases obviously,it is explained that the steel mainly exerts its performance of excellent tensile． During the construction of the sheet pile,the settlement in vertical direction of sheet-pile wall is smaller than in horizontal direction． The horizontal movement of soil increases first and then decreases along the direction from the pile bottom to its top．

Based on an example of a ship lock project in South China,the 3D visualization geological model is established by finite element software and the influence of the soil disturbance and the excess pore water pressure on the deformation and stress of the steel sheet pile cofferdam in the construction of the cushion and the mixing pile is analyzed． Because the soft soil has the characteristics of high compressibility,low shear strength,long consolidation time,high sensitivity and large disturbance,the strength of soil decreases first during the continuous construction of mixing pile．Comprehensive factors such as construction load,water pressure and earth pressure are the main causes leading to the large deformation of steel sheet pile cofferdam．Based on monitoring data and expert opinions,the warning control and reinforcement measures are proposed．

The bearing loads and structural characteristics of spillway dam middle piers of the Yangxi Water Conservancy Project are extremely complex,and the thrust of working arc gate reaches 70 000 kN． The stress and strain analysis of the prestressed gate pier for the project is performed by using finite element method． In this paper,the structural characteristics and stress state of the prestressed gate pier are compared with three kinds of supporting structure schemes ( including concrete deep beam scheme,steel structure deep beam scheme and steel anchor block scheme) ,and the optimal scheme is selected． Further,the optimal design value of anchor cable axial tension is determined by optimizing analysis． The result shows that the schemes of steel structure and steel anchor block are superior to that of concrete deep beam with respect to the control of tensile stress within concrete,and the compressive stress distribution at the pier neck of the steel anchor block scheme is uneven． Therefore,the scheme of steel beam is chosen as the optimal one and it is suggested that the main anchor cable axial tension should be controlled in 3 610 kN． These results could be certain references for similar projects of prestressed gate pier．

Mesh generation plays an important role in the finite element method. In hydraulic structures and rock foundation, due to the existence of holes and thin layer structure, such as the galleries, seepage control system, weak seams, joints, and so on, the meshes generation is usually pretty difficult, the poor quality elements, or even illegal elements will be produced inevitably in the process, which causes the results of numerical analysis to be biased or even wrong. At present, the technology of automatic generation of 2D meshes is mature, but when some special areas are encountered, problems such as abnormal interruptions often occur. In this paper, based on the advance front method, the quadrilateral automatic mesh generation algorithm, aiming at the mesh of the thin structures containing the horizontal and vertical edges in hydraulic structures and its bedrock, as well as other complex boundaries, is researched to improve the robustness of automatic mesh generation of complex area, this research is of great significance to the popularization and application of the finite element method in hydraulic engineering. The improved automatic mesh generation algorithm is successfully applied to the seepage analysis case of earth-rock dam, which verify the feasibility, robustness and rationality of the improved method proposed in this paper.

As drainage system is critical for drainage storage, environmental protection and so on, the plan of multi-objective drainage system has very important practical significance.In this paper, a multi-objective planning model of the drainage system is constructed, in which construction cost, pollution reduction, and capacity effect are taken into consideration. The Pareto set of the planning scheme is generated by using particle swarm algorithm(PSO), and planning decision is made by coupling grey related projection(GRA) to optimize Pareto set. This model is used in the drainage system in Shanghai Songjiang high standard farmland-rice cropping region. The results show that the optimal plan for the rice area recommends drainage duration of 5 days, ditch depth of 1.3m and 1.7m, distance of 77m and 270m, and optimized water rate of 7.64%. Compared with traditional single-objective planning scheme under rainfall design criteria, this model increases stagnant water with 648.5 m3/hm2, reduces total nitrogen per unit area 4.22 kg/hm2, the reduction rate of total nitrogen increases by 28.1% and the relative rice production is about 96.2%. This model can objectively weigh the contradiction of multi-objectives and make scientific decisions, which has a certain significance for the planning and construction of drainage system for water saving and emission reduction in the rice cropping areas in south China.