CHARACTERISTICS OF EVOLUTION OF POTENTIAL EVAPORATION IN TIANJIN REGION OF CHINA

The characteristics of seasonal and annual changes of potential evaporation, the variations of thermal and dynamical evaporation in different seasons and the relationships between potential evaporation and meteorological elements were analyzed according to the observed data of 9 stations from 1961 to 2001 in the Tianjin region of China. Analyses indicate that thermal evaporation is the main part of the potential evaporation and offers about 90%o fraction of to it in summer, while in winter the dynamical evaporation is greater than the thermal one, especially in Jan. , offering 100% contribution, that the influence of temperature on the change of potential evaporation was much larger than that of wind, vapor pressure and sunshine duration, and potential evaporation increased by 30. 33mm with temperature raise 1℃, and that potential evaporation had a surprising increasing tendency, in particular during the recent decade, with the velocity of 4. 22mm/a. The potential evaporation in the Tianjin region will be higher than the past, especially on the global warming background, so that it has the great effects not only on the climatic forcing changes, but also on development of city and economy.     

PREDICTION OF HYDRODYNAMIC PERFORMANCE OF THE FLAP RUDDER

1.　INTRODUCTIONAs an unconventional type of rudder,the flap rudder can enhance the lift force,improve the hydrodynamic performance and delay the occurrence of separation comparedwith normal rudders.Therefore flap rudders have been used on ships in many cases.In1 968,Kato etal.did the experimental researches on flap rudder in open water[1 ] .In 1 992 ,Kose et al.carried out tests to study the hydrodynamic performance of flap rudder in openwater and behind a propeller[2 ] .The researches …     

STUDY OF HYDRODYNAMIC FORCES OF SHIPS IN NARROW WATERWAY

1 .　INTRODUCTIONInrestricatedwaterssuchasnarrowwater ways,itisnecessarytoknowthemaneuveringcharacteristicsofships .Thecollisionofshipsisoneofthemajorreasonsofshipwreckintheworld .Thecollisionsmayoccurforavarietyofreasons .Theymaybedue ,amongotherthings ,tohumanerror ,mechanicalfailure ,weatherandwa terconditions .Butthehydrodynamicforcesbe tweentwoshipsandbetweenshipandbank ,theeffectofdepthofwateralsochangethemaneuver ingcharacteristicsofshipsgreatly .Innarrowwa terways ,specially ,the…     

RANDOM ANALYSIS OF HYDRODYNAMIC CHARACTERIS-TICS OF TRAJECTORY JET CAUSED BY DIFFERENT TYPES OF PIERS

1.　INTRODUCTIONThe energy dissipation problem of overflow damsisalwaysofgreatconcern to hydraulicengineers.Friction and collision,which can be produced by bottom current,surface currentand water jetlashing,are two primary ways of energy dissipation.Designers can deal withthe problem according to their own situation.In this paper,some experiments are reportedon the tail pattern ofpiers.Itis well known thatdeep pithole and far horizontal distance ofthe jet trajectory occur when a flat-tail…     

DISCOVERY OF ANOTHER KIND OF NON-PROPAGATING SOLITARY WAVE

With the consideration of surface tension in the analysis of non-propagating soli-tary waves,the plane kh-σ can be divided into 3 parameter regions.Solitary waves appearing iraparameter regions(1)and(2)are of the same kind which were observed and confirmed before.Now in laboratory we have observed solitary waves in parameter region(3),which has not beenreported before.In this paper,we confirm that it is another kind of non-propagating solitarywave.     

DESIGN METHOD OF LEG STRUCTURE OF JACK-UP RIGS

The structural failures of jack-up rigs were mostly found in leg structures,dueto cracks in way of connections between tubular members of leg structures.Although,stresscalculations of leg structures can be made by using“finite element techniques”,it takes a lot oftime to complete the calculations for the full cases of all working conditions because of manytubular members.Therefore,a simple method for the stress calculations for design purposes isstrongly desired.This paper desribes a simple stress calculaiton method of leg structures andshows a satisfactory results as compared with the results obtained by a detailed calculationmethod.     

CONCURRENT SORPTION OF HEAVY METAL POLLUTANTS OF SEDIMENT OF DIFFERENT GRAIN SIZES

Generally, sediment in natural rivers is non-uniform, and sorption capacities of different grain sizes vary greatly. In order to quantitatively describe sorption of heavy metal pollutant by sediment in natural rivers, the concurrent sorption by sediment of different grain sizes should be studied. By combining systematic laboratory experiments and theoretical analysis the concurrent equilibrium sorption model and the concurrent sorption dynamic model by sediment of different grain sizes have been set up. Both of them indicate that there is no competition or interference among different grain sizes, its sorption content of unit weight of sediment is the sum of the sorption contents of each grain sizes , and the content of each grain size in non-uniform sediment. Furthermore, formulas for determining characteristic parameters ( b and k) in the Langmuir sorption isotherm for non-uniform sediment are deduced as follows: These can be used as a tool for predicting the sorption content of non-uniform sediment     

SEEPAGE CONTROL OF WEAKENED ROCK FOUNDATION OF GEZHOUBA ERJIANG-SLUICE

It is the presence of weakened intercalations that makes the foundation ofGezhouba Erjiang-Sluice complex. Seepage control installation must be able not onlyto reduce seepapge pressure, but also to protect weakened intercalations fromencroachment of seepage. In this paper theoretical analysis has been conducted toprove that well system is highly effective seepage control installation meeting thisdemand. By means of in-situ monitoring it has been verified that proposed seepagecontrol measure relying mainly on drainage is of success. Seepage stability ofweakened intercalations must be considered in employing drains to control seepage,while the seepage deformation of weakened intercalations is different from that ofordinary sand-gravel. Mechanism of seepage deformation of weakened intercalations hasbeen expounded. Seepage wedging is a special type of seepage deformation for weakenedintercalations, It is shown clearly that seepage deformation of intercalations doesnot mean seepage failure of the foundation. In such a foundation as that of Gezhoubasluice, the permeability is distributed randomly. So the seepage field is anunstable, stochastic field.     

EVALUATION OF THE CUMULATIVE FORMATION OF HIGH-SPEED LIQUID JETS

1 .　INTRODUCTIONHigh speedliquidjetsareoftenseeninrainerosionsimulationofaircraftandmissiles ,JilbertandField[1] and jetcuttingofmaterials ,Kob ayashi[2 ] .Inthegenerationofjets ,itistechnicallyinterestingtoknowhowtooperatetheexperimen talfacilityattheoptimumconditiontoobtainthejetvelocitymostefficiently .ThisisdescribedbyShiandTakayama[3] ,ShiandItoh[4 ] ,ShiandIt oh[5] .Intheearlieststudyofa pulsedhigh speedliquidjet ,BowdenandBrunton[6 ] puttheliquidinanozzleandthenusedaslugimpact…     

NUMERICAL SIMULATION OF THE FLOW PATTERNS OF YUQIAO RESERVOIR

In this paper the slot method is used in the computation of 2-dimensional flow withtransient boundary.The slot located inside the computation zone is placed in each space grid,parallel to both X and Y axes.Combined with the operator splitting method,the numerical simu-lation of the flow patterns of Yuqiao Reservior is made.The calculated results are in good agree-ment with observed data.     

隧洞衬砌伸缩缝间距设计与裂缝开展宽度计算

建立了考虑变温和内水压力联合作用下的隧洞衬砌伸缩问题，裂缝开展宽度计算方法，并给出了相应的计算表达式。     

浅谈西湖水库除险加固工程大坝砌石体充填灌浆施工

重力坝砌体容重对大坝的安全影响很大.文章对采取哪种砌体充填灌浆方法增加砌体容重进行了分析和总结.     

非饱和土边坡吸力量测的实践

为探明非饱和土天然土坡和填方土坡中吸力的变化规律，同时比较不同量测方法的效果，在湖北省枣阳市大岗坡泵站，分别用张力计、热传导探头和滤纸法进行了为期３个月的现场吸力量测。文章提交了吸力测量的结果和有关气象资料。     

刘家峡水电站大坝坝基承压水异常分析

2003年某水电站坝基承压水水压发生十分罕见的大范围、大幅度异常突降，一夜之间承压水水位下降23.8 m，自动化监测系统记录了突变全过程。文中根据自动化观测数据，分析异常期间大坝变形、扬压力、渗流量的变化以及对大坝安全的影响;并根据形变场与渗流场相互作用，提出坝基承压水水压与基岩岩块变形位移相互作用的机理关系，得到了实测数据的支持和验证。坝基承压水异常后，承压水水位与库水位的相关关系甚好，其相关系数大于0.997，标准差小于0.07 m，回归方程满足真值方程的条件，对形变场与渗流场耦合作用和短时间形变回弹     

浅析建设项目工程价款的结算

根据基本建设程序,分析了建设项目工程结算,有利于节约工程投资,提高投资效益.     

水对针孔试验鉴定分散性粘土结果影响的试验研究

通过研究土样配制用水和冲蚀用水对针孔试验鉴定分散性粘土结果的影响．认为在西郊和三坪土样中土样配制用水对土样的分散鉴定结果影响较小，而冲蚀用水对土样分散性鉴定结果可以产生很大的影响。     

飞剑潭水库大坝防渗加固工程施工

介绍飞剑潭水库大坝防渗加固工程的处理方案、设计参数、施工方法，及特殊情况处理措施和施工质量控制方法。     

观音河水库病险坝坝体土渗透系数的分析确定

根据观音河水库病险土石坝现有的勘测、试验、运行和险情实测资料等条件，提出了分析确定坝体土渗透系数的方法和结果，并用这组渗透系数计算不同实测情况的浸润线，得到计算与运行经验或实测基本一致的结果，表明了这样确定的坝体土渗透系数的有效性。     

七一水库心墙土坝变形应力研究

土坝应力——应变关系具有明显的非线性特征．采用了非线性有限元法对七一水库土坝进行变形和应力分析，全面了解坝体自施工以来的变形和应力变化规律、计算结果符合现状，并由此采取相应坝体加固措施，改善坝体的应力状态，可以解决坝体变形问题，达到除险加固的目的．