Anhui and Huaihe River Water Resources Institute

Bengbu, China

Anhui and Huaihe River Water Resources Institute

Bengbu, China
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Wu S.-Y.,Anhui and Huaihe River Water Resources Institute | Song X.-J.,Anhui and Huaihe River Water Resources Institute | Song X.-J.,Hohai University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010

An idea of dividing the dams and levees into three regions by seepage flow state and the rule of no flow state influence between the upstream and downstream region under fixed flow quantity are proposed. It will enable the seepage analysis and calculation of dams and levees to be simplified and convenient. New theoretical formulae for the following aspects are derived: the location of inflection point of upstream phreatic line, the analytical extension formula of downstream phreatic line and the undetermined constant before this formula, the additional length of downstream seepage path. According to the Normurov's theory ΔL1=C1H1-C2q/k and the Kochina's theory q/k=μh0, the proportional coefficients C1 & C2 of the additional length of upstream seepage path as well as the ratio μ between the flow quantity and the height of release point are calculated. As a result, C1 is entirely equal to the corresponding data C0 of slope with confined flows. On the basis of these data, the formulae with enough precision by fitting method are given for the purpose of convenient application. For the dams and levees with tail water, two empirical formulae for the height of release point and the additional length of downstream seepage path are presented. The results conform to those by the finite element methods.


Wu S.-Y.,Anhui and Huaihe River Water Resources Institute | Qian C.-F.,Anhui and Huaihe River Water Resources Institute | Qian C.-F.,Hohai University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

At the both sides of rivers in alluvial plain, the double strata with of upper clay stratum over sand stratum are ubiquitous. For their seepage calculation, there are many systematic theoretical solutions with different boundary conditions. However, the corresponding seepage calculations of levees themselves are widely different from the conditions of homogeneous subgrade and impervious subgrade, whereas there are no theoretical solution. The confined water level in sand stratum under the levees is first calculated, the water level of the middle cross section of levee is almost equal to the confined water level. According to the above discussion, and for the convenience to solve the problem, the integral levee is divided from the middle cross section into two parts, i. e., upstream part and downstream part. For each part, the upstream and downstream boundaries are regarded as stretching to infinite, then by using the conformal translation method, the theoretical solutions of each part of the levee are derived. For the usual slope ratios of levees in China, upstream of 1∶3 and downstream below the release point of 1∶5, numeral results and illustrative example are given. For the downstream part of levees, which is the key place of safty analysis, a series of fitting formulae according to the detailed numerial results are given for convenient application. Compared with the results of electric analog tests, the simplified theoretical solutions possess higher precision. All the results can be extended fully to the levees on the multi-strata foundation with surface clay stratum, and to other slope ratios.


Wei K.,Anhui and Huaihe River Water Resources Institute | Song X.,Anhui and Huaihe River Water Resources Institute | Zhou S.,Anhui and Huaihe River Water Resources Institute | Zhang H.,Hohai University
Journal of Hohai University | Year: 2015

Ground-penetrating radar (GPR) technology was used to detect the abnormality of a gravel cushion, and the characteristics of GPR response to four abnormal defects, including gravel cushion shedding, gravel cushions with dense and loose interfaces, a gravel cushion with varied thickness, and a gravel cushion filled with loose rock, were studied. Through temporal profile evaluation, drilling data validation, and comparative analysis of a typical single-channel time-domain waveform and its frequency spectrum, the results show the following: the typical single-channel waveform for gravel cushion shedding is characterized by an absence of the event on the profile, the reverse phase of the weak reflection of the interlayer, spectral energy distributed over the whole frequency range, and strong signals appearing in the 550 to 800 MHz bands; the typical single-channel waveform for the gravel cushions with dense and loose interfaces presents the event on the profile, spectrum energy that concentrates in the low-frequency area, and more energy peaks; the typical single-channel waveform for a gravel cushion with varied thickness shows the time difference in reflected waves between the upper and lower interfaces (upward convex event or pull-down event); the typical single-channel waveform for a gravel cushion filled with loose rock shows strong-amplitude complex waves (a random event with a diffraction fringe), significant energy peak superposition, and a higher peak. ©, 2015, Editorial Office of Journal of Hohai University (Nature Sciences). All right reserved.

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