Time filter

Source Type

Chen J.,State Key Laboratory of Hydrology | Chen J.,Hohai University | Liu X.,Hohai University | Wang C.,University of California at Berkeley | And 6 more authors.
Environmental Earth Sciences | Year: 2012

Despite its extreme aridity, the Ordos Basin in northern China is rich in groundwater. Many artesian wells or springs with large fluxes are utilized for drinking, irrigation and industrial production. In a search for the origin of the groundwater, a detailed investigation of the stable isotopes of oxygen and hydrogen in the local precipitation, the river water, the springs, the well water, as well as the soil water extracted from six soil profiles in the Ordos Basin, was carried out. The data show that δD, δ 18O and TDS values of the river water are similar to those of groundwater, while the TDS values of the soil water are about ten times greater than those of groundwater. Furthermore, the mean isotopic compositions of the local precipitation are significantly higher than those of river water and groundwater. Based on the chloride mass balance method, the estimated recharge rates range from 5.2 to 17.2 mm/year, with a mean value of 10.5 mm/year. The results show that the main source of recharge of the groundwater in the Ordos Basin is not the local precipitation, but must come from a region where the precipitation is characterized by much lower δD and δ 18O values. In addition, the groundwater in the Ordos Basin contains a component of mantle-derived 3He and crust-derived 4He suggesting that the groundwater may partly derive from flows through basement faults beneath the Ordos Basin. © 2011 Springer-Verlag.

Zhu S.,State Key Laboratory of Hydrology | Wang Y.,State Key Laboratory of Hydrology | Feng S.,Hydrochina Zhongnan Engineering Corporation | Zhong C.,State Key Laboratory of Hydrology
Proceedings of the 12th International Conference on Engineering, Science, Construction, and Operations in Challenging Environments - Earth and Space 2010 | Year: 2010

Combined with triaxial test data of coarse-grained material, rationality verification and study of constitutive model used commonly in earth dam indicates that Duncan's E-B model and SHEN Zhujiang's double-yield-surface model both well reflect the stress-strain relationship of pre-broken coarse-grained material under general triaxial test. Using general triaxial test parameters, deformation of coarse grain calculated under the path of equal stress ratio is done; whose decrease of volume strain and increase of shear strain is great difference compared with the experimental result. Nonlinear elastic model and Shen Zhujiang's double-yield-surface model could fit the result of triaxial test under equal stress ratio well when they are modified combined with the stress path of equal stress ratio. the main reason of great calculation error is that elastic parameters obtained by general triaxial experiment are applied to calculate them under complex stress path in high rockfill dam, by assuming the elastic parameters independence on stress path. Reasonable stress-strain constitutive model must reflect dam's real loading stress path objectively. © 2010 ASCE.

Jia D.-D.,Nanjing Hydraulic Research Institute | Jia D.-D.,China Institute of Water Resources and Hydropower Research | Shao X.-J.,Tsinghua University | Zhang X.-N.,State Key Laboratory of Hydrology | Ye Y.-T.,China Institute of Water Resources and Hydropower Research
Journal of Hydraulic Engineering | Year: 2013

This paper is focused on the sedimentation processes of fine-grained particles in a 14-km-long section upstream of the Three Gorges Dam, referred to as the dam area, during the period from March 2003 to October 2006. Field measurements indicated that sediment deposits in the dam area were mostly found at the bottom of the main channel, where a new river bed was formed with a flat, nearly horizontal surface. In contrast, very little deposits could be found on the bank slopes of the channel. The observations disagree with the previous predictions based on numerical models, which suggested more evenly distribution of deposits over the cross section. This paper explains the discrepancy by identifying the motion of muddy deposits by gravity as a key process in the dam area. A three-dimensional (3D) full Reynolds-Averaged Navier-Stokes (RANS) model is applied to calculate the flow and sediment transport processes. A critical slope method (CSM) is used to estimate the downslope movement of muddy deposits in the bottom by gravity. The formation of bottom deposits is successfully simulated using this approach. The simulated sedimentation patterns agree well with field observations. © 2013 American Society of Civil Engineers.

Huang Y.,Hohai University | Tang Y.,Hohai University | Zhou Z.,Hohai University | Yu Z.,University of Nevada, Las Vegas | Yu Z.,State Key Laboratory of Hydrology
Environmental Earth Sciences | Year: 2014

Experiment equipments involved in the single tube fracture and double tube fracture models are designed to research the characteristics of groundwater flow and solute transport in filled fracture. During the experiment, the state of groundwater flow can be characterized as linear flow, and satisfies Darcy's law. Therefore, based on the pipe flow of hydraulics and Darcy's law, the flow rate and water flow velocity can be calculated. Also, dispersion parameters were calculated with the fitting of observed data and analytical solution in the single tube fracture model. Furthermore, effects of some factors on solute transport are involved in the double tube fracture model, and length of branch fracture, particles' diameter and flow rate in water inlet have been discussed. Results show that the arrival time of concentration peak value in the single tube fracture model is faster than that in the double tube fracture model, and two concentration peak values exist in the double tube fracture model. Arrival time of concentration peak value is faster with the increase of branch fracture length. Furthermore, if the branch fracture is longer, arrival time of the first concentration peak value is faster, while arrival time of the second concentration peak value is slower, relative to short branch fracture. © 2013 Springer-Verlag Berlin Heidelberg.

Xu H.,Nanjing Hydraulic Research Institute | Xu H.,State Key Laboratory of Hydrology | Xu H.,Hohai University | Xia Y.,Nanjing Hydraulic Research Institute | And 5 more authors.
WIT Transactions on the Built Environment | Year: 2013

The local scour around structures is one of the key problems in channel regulation works. In this paper, a series physical model was carried out to analyze a submerged dike, the north and south diverting dike of Shuangjian Shoal protection project in the Fujiang Shoal channel of the Lower Yangtze River regulation works, focusing on the depth, scale and influence factors of local scour. Bottom topography changes under different and optimized apron widths were also studied. The series model results show local scour is strong under the present design apron width with the action of overtopping currents, and it is substantially reduced under optimized apron depth. The results of the series model have been compared with the complete model. It is concluded that, firstly the location and pattern of a scour hole are similar to both models, but the maximum scour depth and scope of a scour hole by the complete model are larger than those of a series model. Secondly, results by a series model are more reliable and, finally, the results provide experience and reference for channel regulation and apron design in similar river research. © 2013 WIT Press.

Xiangqian F.,Nanjing Hydraulic Research Institute | Xiangqian F.,State Key Laboratory of Hydrology | Shaowei H.,Nanjing Hydraulic Research Institute | Shaowei H.,State Key Laboratory of Hydrology | And 3 more authors.
Construction and Building Materials | Year: 2016

In order to real-time monitor the internal damage of concrete and discussbasic characteristics of acoustic emission (AE) of concrete prism specimens under dynamic uniaxial tension, as well as the dynamic performance and failure mechanism of concrete, effect of the dynamic performance on structure are studied thoroughly, based on the AE rise time, ringing counts, energy, duration and amplitude of 60 different initial static load and different initial damage concrete dynamic axial tensile AE characteristics tests divided into 10 groups. Results are as follows: With the increase of initial quasi-static load value, the increase rates of acoustic emission parameters for concrete under dynamic loads gradually decrease; The larger the initial quasi-static load value is, the more difficult to identify the load's stable stage according to the acoustic emission signal, and the more significant hysteresis effect of concrete damage is; Under dynamic loads, the acoustic emission signal for concrete prism specimens also accord with Kaiser effect; Kaiser effect is determined mainly by the interior damage level of concrete specimens, not by the magnitude of load; The more initial loading cycles, the higher the degree of damage of specimens is, and the less acoustic emission signals are produced within the dynamic loading stage. © 2016 Elsevier Ltd.

Loading State Key Laboratory of Hydrology collaborators
Loading State Key Laboratory of Hydrology collaborators