DISCUSSION OF "An Economical Approach to Determining the Extent of Ground-Water Contamination and Formulating a Contaminant Removal Plan", by Kiyoshi W. Mido, January-February 1981 issue, v. 19, no. 1, pp. 41–47     

Ed Low  Civil Engineer 《Ground water》1981,19(4):432-434

  相似文献   

波阻抗反演正则参数估计   总被引：24，自引：0，他引：24       下载免费PDF全文

张宏兵  尚作萍  杨长春  段秋梁 《地球物理学报》2005,48(1):181-188

为了解决用正则化方法能够将波阻抗反演的病态问题转为良态问题,通过统计方法合理地选择正则参数的初值,在反演过程中用极大似然（ML）方法实时进行正则参数值估计,提高反演收敛速度,改善反演结果。同时,在具体反演中将正则化方法与快速模拟退火算法相结合,充分发挥正则参数作用,可以获得全局最优解,取得了好的实际应用效果。  相似文献   

Analytic Solution of Elasto-Plastic Stress in Infinite Slope under Uniform Load     

WANG Nianxiang GU Lei Senior Engineer  Geotechnical Engineering Department  Nanjing Hydraulic Research Institute  Nanjing  P. R. China. Engineer  Plan  Statistics 《中国海洋工程》1999,(2)

-According to the Mohr-Coulomb yield criterion,the stress field of the infinite slope is derivedunder a vertical uniform load q on the top of the slope.It is indicated that elastic and elasto-plastic stateswould occur in the slope.When q is smaller than the critical load,q_p,the slope is in the elastic state.Ifq equals q_p,the slope is in the critical state,and the plastic deformation would occur along the critical an-gle.With the increase of q,the plastic zone would extend,and the slope is in the elasto-plastic state.Ifq equals limit load,the slope is in the limit equilibrium state.The slope may be divided into three zones.Some charts of the critical angle,the critical and limit load coefficients are presented in this paper.  相似文献   

Numerical Model of Total Sediment Transport in the Yangtze Estuary   总被引：2，自引：2，他引：0  

DOU Xiping LI Tilai  DOU Guoren Senior Engineer  River  Harbour Engineering Department  Nanjing Hydraulic Research Institute  Nanjing  P. R. China Senior Engineer  Nanjing Institute of Hydrology  Water Resourses  Nanjing  P. R. China Academician  Nanjing Hydraulic Research Institute  Nanjing  P. R. China 《中国海洋工程》1999,(3)

Based on the non-equilibrium suspended load transport equation,bed load transport equationand sediment transport capacity formulas derived by Dou et al.,a 2-D numerical model of total sedimenttransport in the Yangtze Estuary is presented.In the model,the actions of tidal currents and wind waves andthe effect of salinity on sediment transport are considered.An automatically generated boundary-fitted grid isused to fit the boundaries of the estuary and the boundaries of engineering projects.The verification of calcu-lations shows that the sediment concentration,the deformation of riverbed and siltation in the channels causedby typhoons can be successfully simulated.  相似文献   

A Model for Nonlinear Irregular Waves in Coastal Area     

朱良生  张经汉  李少英 《中国海洋工程》1999,(4)

Based on the refraction-diffraction theory of irregular waves in the waters of slowly-varying cur-rents and depths,and the generation dissipation theory of wind wave,a model for nonlinear irregular wavesin coastal area is developed.In light of the specific conditions of coastal wave character and engineering ap-plication,a practical mathematical model for the nonlinear irregular waves is presented.with directional spec-trum in coastal area.Coast effect,refraction,whitecapping.bottom friction.current,wind and nonlinearaction are considered in this model.The numerical methods and schemes for wave refraction ray,energy con-servation of propagation,energy balance of the generation and dissipation of wind waves have been studied.Finally,the model is used for the directional wave spectrum computation in the Daya Bay.Compared withthe measured data with 956 wave bouys in the Daya Bay,the model results are in good agreement with themeasured results.  相似文献   

Reflection of Short Waves     

Miguel A. LOSADA 《中国海洋工程》1999,(1)

—According to the energy equation,the relation between reflection and energy losses for shortwaves from mild beaches is established and analysed.A reflection coefficient varying with position and en-ergy losses is proposed.Different reflection tests are conducted to check the theoretical analysis.A modi-fied method to estimate the reflection coefficient at varied water depths is suggested based on the linearwave theory.The study indicates that the reflection coefficient from mild beaches has a changing trend forshort waves approaching shoreline.  相似文献   

Study on the Length of Cross-Bay Bridge at Tieshan Port     

YOU Lixin MIAO Difan Engineer  No. Harbour Engineering Investigation  Design Institute of the Ministry of Communications of China  Wuhan  P. R. China 《中国海洋工程》1999,(4)

To determine the optimal length of the cross-bay bridge at the Tieshan Port and the impact ofthe bridge on the hydrological environment,a 2-D numerical model is adopted to calculate the variation oftidal level,tidal current field and tidal discharge caused by different lengths of the bridge.  相似文献   

Ice Induced Low Temperature Fatigue Crack Propagation in Offshore Structural Steel A131     

DUAN Menglan  GAO Zhaojie  LIU Chuntu Senior Engineer  China Classification Society  Beijing  China. Research Professor 《中国海洋工程》1998,(3)

To investigate the low temperature fatigue crack propagation behavior of offshore structuralsteel A131 under random ice loading,three ice failure modes that are commonly present in the Bohai Gulfare simulated according to the vibration stress responses induced by real ice loading.The test data are pro-cessed by a universal software FCPUSL developed on the basis of the theory of fatigue crack propagationand statistics.The fundamental parameter controlling the fatigue crack propagation induced by randomice loading is determined to be the amplitude root mean square stress intensity factor K_(arm).The test resultsare presented on the crack propagation diagram where the crack growth rate da/dN is described as thefunction of K_(arm).It is evident that the ice failure modes have great influence on the fatigue crack propaga-tion behavior of the steel in ice-induced vibration.However,some of the experimental phenomena and testresults are hard to be physically explained at present.The work in this paper is an init  相似文献   

A Whitecap Coverage Model Based on the Surface Slope For Criterion of Wave Breaking   总被引：3，自引：2，他引：1  

Xu Delun  Yu Dingyong  Lu Hongmin Professor  Physical Oceanography Laboratory  Ocean University of Qindao  Qingdao Associate Professor  Engineering School  Ocean University of Qindao  Qingdao Senior Engineer  Physical Oceanography Laboratory  Ocean University of Qingdao  Qingdao 《中国海洋工程》1998,(1)

Using the limit surface slope as a criterion of wave breaking,a simple model for estimatingthe spatial fraction of breaking surface of sea at an instant,which is regarded as the whitecap coverge inthis paper,is analytically derived from the probability density of surface slope based on Gaussianstatistics.The resulting fraction is found depending on the fourth moment of wave spectum,m_4,as well asthe critical threshold of surface slope.By expressing the fourth moment in terms of the Neumannspectrum,a formula linking the fraction and wind speed for fully developed sea states is obtianed.Anotherformula relating the fraction to both wind speed and fetch(or duration)is achieved by expressing m_4 interms of the Krylov spectrum and applying the empirical relationships used in the SMB ocean wave pre-dicting technique.A comparison between these results and the field data of whitecap coverage collected byMonahan and O＇Muircheartuigh shows an encouraging agreement.  相似文献   

Assessing “Urban Karst” Effects from Groundwater–Storm Sewer System Interaction in a Till Aquitard     

Martin G. Shepley  Nick Schmidt  Matt J. Senior  Stephen R. H. Worthington  Ron B. Scheckenberger 《Ground water》2020,58(2):269-277

Storm sewer systems and their associated utility trenches may strongly influence the effects of urbanization on a groundwater system. This study was undertaken to identify the causes of district-wide basement infiltration in an aquitard system. It comprised widespread continuous monitoring of utility trench wells and dye tracing from storm sewer system exfiltration tests. The results indicate that a major effect of urbanization on shallow groundwater is related to storm sewer system exfiltration, which is marked by a characteristic pattern of head variations in the aquitard unrelated to distributed surface infiltration. The aquitard constrains flow from storm sewer system exfiltration to the utility trench, creating an urban flow path for groundwater discharge. Temporary buildup of water levels in the utility trench drives relatively high-velocity flow through the permeable sewer bedding material of the utility trench to a separate foundation drainage collector system, ultimately causing a severe “urban karst” effect that produces system surcharging and widespread basement water infiltration. The main conditions causing the “urban karst” are the large hydraulic conductivity ratio between the utility trench material and the aquitard, and the shallow depth and low gradient of the storm sewer system imposed by a very flat drainage basin.  相似文献