ECONOMIC EVALUATION OF REDUCTION OF DEPOSITION IN THE LOWER YELLOW RIVER BY THE SANMENXIA PROJECT

ＥＣＯＮＯＭＩＣＥＶＡＬＵＡＴＩＯＮＯＦＲＥＤＵＣＴＩＯＮＯＦＤＥＰＯＳＩＴＩＯＮＩＮＴＨＥＬＯＷＥＲＹＥＬＬＯＷＲＩＶＥＲＢＹＴＨＥＳＡＮＭＥＮＸＩＡＰＲＯＪＥＣＴＬＩＧｕｏｙｉｎｇａｎｄＴＵＱｉｈｕａＡｓｓｉｓｔａｎｔＣｈｉｅｆＥｎｇｉｎｅｅｒ，...     

A Study of Spatial Variability on Aquifer Hydraulic Conductivity K

A structural analysis of K of an aquifer system in the study area is presented, and the main direction and degree of the variability of K are found by using the unstationary regionalized variable theory of geostatistics. Optimal estimation of K has been made by universal kriging method (U K M ). Both spatial variability distribution map and division map of K are given.     

暗绿色硬质亚粘土层桩基的工程地质条件

本文重点叙述了离地表30米以内暗绿色硬质亚粘土层。此土层在上海地区分布较广,土质坚硬,常作为建(构)筑物的桩基持力层,文章从沉积环境、分布状况、土质特性及桩基承载力四个方面进行了分析探讨,並举实例说明。     

Substructure Method of Three-Dimensional Semi-Analytic Boundary Element and Its Application to Seismic Scattering of Hill Topography

In this paper,a substructure method of three-dimensional semi-analytic boundary element is established.The seismic scattering by three-dimensional topography of a hill can be analyzed by the method in frequency domain.Using this method,the computational effort and storage space are reduced considerably.Finally,analytic results are given.     

南水北调中线工程对汉江中下游的影响分析

本文分别计算了丹江口水库１９６９－１９９０年实际下泄流量过程和大坝加高向黄淮海地区调水１５×１０９ｍ３后下泄过程在２０２０水平年下汉江中下游各点的水位流量过程，比较了两者的水位流量差①，分析了丹江口水库调水对汉江中下游各点水位和流量的影响以及引起的灌溉用水和航运的变化。结果表明，丹江口水库调水后，丹江口水库下游各点的多年平均水位、流量将下降，流量过程趋于缓和，洪水流量减少，枯水流量增加；灌溉取水量减少，破坏状况加重，枯水期航运流量增加，但中水期航运时段减少。最后，作者对汉江中下游补偿工程提出了建议。     

Determination of Partial Factors of Breast Wall on Top of Sloping Breakwater

- By applying the theory of structural reliability, reliability analyses for the stability of a breast wall on the top of a sloping breakwater are carried out. Based on the analyses, the method for determining partial action / load factors and partial resistance factors of breast walls is expounded, and the design expressions with partial factors are given. The values of partial action / load factors and partial resistance factors are recommended preliminarily according to the computation for breast walls with typical cross-sections.     

Permeability Heterogeneity in a Fractured Sandstone–Mudstone Rock Mass in Xiaolangdi Dam Site, Central China

Abstract: Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology. Numerous approaches have been proposed to characterize heterogeneity in the last several decades. However, little attention has been paid to correlate permeability heterogeneity with geological information. In the present study, several causes of permeability heterogeneity, that is, lithology, tectonism, and depth, are identified. The unit absorption values (denoted as ω), which are results obtained from the packer test, are employed to represent permeability. The variability of permeability in sandstone–mudstone is so significant that the value of unit absorptions span 3–4 orders of magnitude at any depth with several test sections. By declustering, it has been found that under a similar tectonic history, the means of permeability differ greatly at different formations as a result of different mudrock contents. It has also been found that in the same formation, permeability can be significantly increased as a result of faulting. The well-known phenomenon, the decrease in permeability with depth, is found to be caused by the fractures in the rock mass, and the relationship between permeability and depth can be established in the form of logω–logd. After subtracting the trend of ω with absolute depth, the mean of the residual value at each relative depth can be well correlated with the distribution of mudstone. The methods proposed in this paper can be utilized to research in similar study areas.     

基于信息熵与多重分形理论的非均匀流动分析

根据粘土和壤土中非均匀水流运动的示踪试验, 研究了土壤水非均匀流动模式, 并基于信息熵与多重分形理论探讨了多孔介质中流动的非均匀性质.不同土质试验研究的分析结果表明, 各深度信息熵与特征长度具有相反的变化趋势.非均匀流动多重分形特性分析表明, 非均匀流动分布具有很强的自相似性, 但并不是在所有研究尺度范围内都满足标度不变性, 在显色比例相近的情况下, 壤土和粘土中水流运动标度不变性的范围表现出显著的差异.      

Evaluation of total load sediment transport formulas using ANN

The calculated results from various sediment transport formulas often differ from each other and from measured data. Some parameters in the sediment transport formulas are more effective than others to estimate total sediment load. In this study, an Artificial Neural Network （ANN） model is trained using four dominant parameters of sediment transport formulas. ANN models are able to reveal hidden laws of natural phenomena such as sediment transport process. The results of ANN and some total bed material load sediment transport formulas have been compared to indicate the importance of variables which can be used in developing sediment transport formulas. To train ANN, average flow velocity, water surface slopes, average flow depth, and median particle diameter are used as dominant parameters to estimate total bed material load. Two hundreds and fifty samples are used to train the ANN model. Twenty-four sets of field data not used in the training nor calibration of ANN are used to compare or verify the accuracy of ANN and some well-known total bed material load formulas. The test results show that the ANN model developed in this study using minimum number of dominant factors is a reliable and uncomplicated method to predict total sediment transport rate or total bed material load transport rate. Results show that the accuracy of formulas in descending order are those by Yang （1973）, Laursen （1958）, Engelund and Hansen （1972）, Ackers and White （1973）, and Toffaleti （1969）. These results are similar to those made by ASCE （1982） based on laboratory and field data not used in this paper. Study results also show that the formulas based on physical laws of sediment transport, like those formulas that were developed based on power concept, are more accurate than other formulas for estimating total bed material sediment load in rivers.