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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.

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.

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.

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.

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.

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