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Niu X.,Changjiang Institute of Survey Planning Design and Research
Engineering | Year: 2016

To date, the Three Gorges Project is the largest hydro junction in the world. It is the key project for the integrated water resource management and development of the Changjiang River. The technology of the project, with its huge scale and comprehensive benefits, is extremely complicated, and the design difficulty is greater than that of any other hydro project in the world. A series of new design theories and methods have been proposed and applied in the design and research process. Many key technological problems regarding hydraulic structures have been overcome, such as a gravity dam with multi-layer large discharge orifices, a hydropower station of giant generating units, and a giant continual multi-step ship lock with a high water head. © 2016 THE AUTHORS

Niu X.,Changjiang Institute of Survey Planning Design and Research | Niu X.,National Dam Safety Research Center
Shuili Fadian Xuebao/Journal of Hydroelectric Engineering | Year: 2017

Achievements in construction of concrete face rockfill dams (CFRDs) is remarkable in China, particularly in rapid development and large quantities of high dams. But certain dangerous situations have appeared with these dams: serious seepage, structural crack, vertical joint extrusion damage, etc., especially with high dams. This paper sums up the current situations of this type and challenges to the design and construction of high CFRDs, and identifies technical problems in the existing design theory, analysis method and technical standard. Our analysis reveals three major problems: insufficient research on design theory, low accuracy in analysis method, and lack of good integrity in technical standard. Therefore, we suggest a new design concept of high CFRDs that focuses on face panel reliability and considers four aspects: control of dam deformation, durability of the panels, adaptive capability of the panels, and repairing of dam body. © 2017 All right reserved.

Zhan C.,CAS Institute of Geographical Sciences and Natural Resources Research | Zeng S.,Changjiang Institute of Survey Planning Design and Research | Jiang S.,Beijing Normal University | Wang H.,Beijing Normal University | Ye W.,Beijing Normal University
Water Resources Management | Year: 2014

Climate change and human activities have been identified as the two main reasons for the change in runoff. To better understand the factors causing runoff change, this paper develops an integrated approach which combined the elasticity coefficient approach (including a non-parametric model and six Budyko framework based models) and the hydrological modelling approach (using SIMHYD models) for partitioning the impacts of climate change and human activities on surface runoff. The Guanzhong River Basin(GRB), which is the sub-basin of the Wei River basin in China is chosen as the study area. In this study, trends in runoff, rainfall and potential evapotranspiration (PET) from 1958 to 2008 are analyzed using the Mann-Kendall test and change-points in the annual runoff from 1958 to 2008 are sought using the Fu formula, Mann-Kendall test and double mass curve. The calibrated and validated rainfall-runoff model SIMHYD is used to simulate the runoff in the GRB during 1958-2008. Seven different methods are used to calculate the elasticity coefficient and then the elasticity coefficient methods are used to evaluate the contribution of climate change and human activities. Combining all these results, the contribution of climate change and human activities to runoff change is 34.1~47.3 and 52.7~65.9 %, respectively. The study provides scientific foundation for understanding the causes of water resources decrease and significant information for water resourcesmanagement under the influence of climate change and human activities. © Springer Science+Business Media Dordrecht 2014.

Lu X.,CAS Wuhan Institute of Rock and Soil Mechanics | Liu Q.,CAS Wuhan Institute of Rock and Soil Mechanics | Su P.,Changjiang Institute of Survey Planning Design and Research
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

The rock dilatancy-bulking deformation characteristics under high geostress unloading condition are critically important to understand the stability evolution and control mechanism of deep roadways, and to evaluate the stability of surrounding rocks. Using the triaxial unloading tests on the rocks sampled from the Gubei colliery, the evolution characteristics of the typical stresses with confining pressure are first studied. The criterion of rocks approaching pre-peak damage dilatancy and post-peak bulking deformation under critical condition is proposed. Then, the damage and degradation process of mechanical parameters of rocks during unloading are considered, and a progressive failure constitutive model is subsequently constructed. Finally, the distinct element code UDEC is embedded into the model to realize nonlinear numerical calculation. Simulation results of triaxial unloading tests show that the proposed model is suitable for describing the rock dilatancy-bulking deformation characteristics. Besides, the proposed model is used to evaluate the excavation damaged zone (EDZ) around a deep roadway. Compared with classical Mohr-Coulomb strain softening model, the performances of the proposed model are suggested to be applicable for practical engineering, and helpful for stability analysis and maintenances of deep roadways.

Gui S.-Q.,Tsinghua University | Gui S.-Q.,Changjiang Institute of Survey Planning Design and Research | Cheng X.-H.,Tsinghua University
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2014

Little information is available regarding the impacts of heating and cooling processes on the geotechnical performance of piled foundations incorporating pipe loops for ground-source heat-pump systems (so-called energy piles). A pile-loading test that couples thermal loading cycles with a constant external mechanical load is undertaken to investigate the behavior of an energy pile installed in Xinyang, Henan, China. The pile-loading test is carried out over a period of about four weeks, during which the thermal and mechanical loads are jointly applied in order to simulate the working conditions of energy piles. Using the vibrating-wire extensometers, the temperature and strain profiles of the test pile are monitored. Meanwhile, the load and movement at the pile head, the ambient air temperature and the inlet/outlet temperatures of circulating fluid in the pipes embedded in the pile are also recorded using the conventional instrumentation methods. The additional thermal stresses mobilized in the pile shaft are calculated based on the measurements, and the structural responses of an energy pile can be understood according to the simplified mechanism. The additional thermal stresses (tensile or compressive) superposed to the mechanical stresses mobilized in the pile during the heating and cooling processes are also subjected to the restraint conditions at the ends of a pile. The additional thermal stresses can possibly exceed the limit design stress values specified by a design code, which needs to be carefully considered in the structural design of an energy pile.

Li X.,Hubei Engineering University | Wang B.,Changjiang Institute of Survey Planning Design and Research | Zhou G.,Sinohydro Bureau 8 Co.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2012

Deeply buried underground engineering often faced with a high geostress environment. Based on the research of the conception of "deep stratum" and "deep engineering", through collecting about 600 groups of the measured geostress data in deep rocks of China mainland, the distribution of the vertical stress, the largest horizontal principal stress, the minimum horizontal principal stress and the lateral pressure coefficient varying with depth in Chinese mainland are shown in this paper. The features of the geostress in deep rocks are elementarily analysed refer to the analysis method of Hoek and Brown, the distribution rule of the vertical stress, the maximum and the minimum horizontal principal stresses with depth in deep stratum are regressive analysed, and trend of the lateral pressure coefficient with depth is also discussed.

Zhang S.,Changjiang Institute of Survey Planning Design and Research
Modern Tunnelling Technology | Year: 2014

Based on the specific karst research on metro lines in Wuhan area and according to the long-term observations of karst groundwater level and results of pumping test, some hydrogeological features of shallow karst groundwater as groundwater table, permeability, water condition and hydraulic connection in each aquifer group are deeply analyzed. Studies show that the influences of shallow karst groundwater on underground engineering mainly refer to the water burst and mud gushing in the process of underground engineering, the karst ground collapse probably induced by groundwater activity during operation, and the influence of local groundwater level rising on designed waterless tunnels. Aiming at different hydrogeological problems, safety risks and its severity, various treatment schemes as deep well dewatering, backfilling of karst caves, water-stop curtain grouting and waterproofing & anti-floating of structures, etc are put forward. ©, 2015, Editorial Office of "Modern Tunnelling Technology". All right reserved.

Wang Q.,Changjiang Institute of Survey Planning Design and Research
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2011

The gravel and pebble is a common kind of coarse-grained soil in the riverbed of hydropower project, but its engineering properties have a significant impact on the layout of the dam project while its thickness is much large. The study object is the gravel layer deposited lately in Shangjiang to Qizong river reach riverbed of Jinsha River, which is much thick. The study employs some comprehensive methods, such as exploration, grain size analysis, in-situ tests, and laboratory tests of physico-mechanical properties for imitated gradation sample, and find out that this layer has the frame from coarse grains and some geological characteristics of this layer, such as much high bearing capacity, shear resistance, modulus of deformation and elasticity, and moderate to heavy permeability. This paper discusses the engineering geological problems from different plans while using this layer or clearing it. The study result provides the geological basis for the study of building dam on the gravel layers, and there is a certain reference value for similar projects and the soil mechanics study.

Niu X.-Q.,Changjiang Institute of Survey Planning Design and Research
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010

A brief description is made of the safety status of water reservoirs, the hazards of defective and dangerous reservoirs and the rehabilitation works conducted during different periods in China. The characteristics and causes of main diseases and defects of defective and dangerous reservoirs are reviewed in terms of the safety in flood prevention, dam seepage flow, structure and earthquake protection. Relevant rehabilitation methods and main technical points are discussed with respect to various defects on the basis of summarizing the rehabilitation experience for defective and dangerous reservoirs. It is of guiding significance in the on-going works of consolidating defective and dangerous reservoirs in China.

Cojean R.,MINES ParisTech | Cai Y.J.,Changjiang Institute of Survey Planning Design and Research
Journal of Mountain Science | Year: 2011

The water level in the Three Gorges Dam reservoir is expected to change between the elevations of 145 m and 175 m, as a function of the flood control implementation and the intensity of the annual flood. As a matter of fact, the hydraulical and mechanical loadings, related to the water level modifications, will result in alterations in the slope stability conditions. The town of Badong (Hubei), of 20 000 inhabitants, is one of the towns which was submerged by the impoundment of the reservoir. As a consequence, the new town of Badong was constructed on a nearby site which appeared to be partly an unstable site. A part of this site corresponds to an old landslide, the Huangtupo landslide, the base of which had to be submerged by the water of the reservoir. The analysis of the Huangtupo landslide, taking into account various events scenarios, drainage and reinforcement measures and monitoring devices, allows to illustrate the general process implemented all along the reservoir in order to mitigate the landslide hazard. © 2011 Science Press, Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg.

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