本文關鍵詞：水利工程對向海濕地水文與生態(tài)的影響，由筆耕文化傳播整理發(fā)布。

3??結論與建議

在干旱、半干旱地區(qū),只有在降雨分布很集中的豐水年,才可能出現(xiàn)一些適合濕地植物生長的濕潤期,而在其他絕大多數時間,地下水埋深很大,不具備濕地特征。外界入水量進入的時機不同,對濕潤程度的提高也不同,影響因素有蒸發(fā)、前期及后期降雨量等。一般來說,在生長期初期和末期,由于蒸發(fā)量相對較小,同樣的水量對濕潤程度的提高相對較大。在力求滿足美國陸軍工程師團的最小水文準則時,該地區(qū)的臨界供水量為12~15cm。對于干旱地區(qū),不同時期的相同來水量,會引起不同的濕潤變化,這對于濕地保護和恢復都是應該注意的問題。臨界水量是該地區(qū)可以維持濕地水文的最小水量,因此在水資源規(guī)劃時,應該給予足夠的認識。

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Studyonhydrologicaldynamicsandformationcriteriaofwetlands

JIAZhong??hua,LUOWan,ZHOUXiao??xia,LIUXiao??ning

(Xi??anUniversityofTechnology,Xi??an??710048,China)

Abstract:ThedataofprecipitationandsoilpropertiesinXi??anareaareanalyzedbyusingthehydrologi??calmodelDRAINMODtoinvestigatetheinfluenceofincomingwateronvariationofgroundwatertable.ThemodelissuggestedbytheWetlandResearchInstitute,DepartmentofAgriculture,USA.Atthesametime,theidentificationcriterioncurrentlyadoptedinUSisappliedtoanalyzethenecessarycriticalincom??ingwaterforwetlandformation.Itisfoundthattheincomingwaterwiththesameflowdischargemayre??sultindifferentwetnessindifferentmonthsinayear.Consequently,thenecessarywaterflowforformingthecriticalhydrologicalconditionisnotaconstant.

Keywords:wetland;wetlandhydrology;DRAINMOD;modeling

(上接第26頁)

FractureanalysisoninducedjointofRCCdams

SONGYu??pu,ZHANGLin??jin,YINFu??xin

(DalianUniversityofTechnology,Dalian??116024,China)

Abstract:Inordertodeducetheformulaforstressintensityfactoroftwo??directionintervaljointinRCCdams,thestressintensityfactorofthecracktipsinellipticalandrectangularinducedjointsareanalyzedbyusing3??DFEM.Thecomparisonshowsthatthecalculationresultsofthesetwokindsofjointareap??proximatelythesame.Buttheellipticalmodelismoreconvenientforpracticaluse.Consequently,theformulaofthestressintensityfactorforthecracktipsofellipticalinducedjointinfinitebodyisextendedtomeetthecalculationforfinitebody.Onthisbasis,theregressionanalysismethodisadoptedtoestab??lishtheformulaforcalculatingthestressintensityfactoroftwo??directionintervaljoint.Intheformulathesizeanddimensionsofinducingplateaswellastheinfluenceofweakeningdegreearetakenintoaccount.Keywords:RCCdam;inducedjoint;stressintensityfactor;3??DFEM

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  本文關鍵詞：水利工程對向海濕地水文與生態(tài)的影響，由筆耕文化傳播整理發(fā)布。