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1.
Geotechnical and Geological Engineering - The Armando Ribeiro Gonçalves Dam, popularly known as The Açu Dam, is an important geotechnical construction in Rio Grande do Norte state,...  相似文献   

2.
This paper aims to reveal the reciprocal influence of Kürtün Dam and wastewaters from the settlements on the water quality in the stream Har?it, NE Turkey. Several key water-quality indicators were measured: water temperature (T), pH, dissolved oxygen (DO), electrical conductivity, water hardness, chemical oxygen demand (COD), ammonium nitrogen (NH4 +–N), nitrite nitrogen (NO2 ?–N), nitrate nitrogen (NO3 ?–N), total Kjeldahl nitrogen (TKN), total nitrogen (TN), orthophosphate phosphorus (PO4 3?–P), and methylene blue active substances (MBAS). The monitoring and sampling studies were conducted every 15 days from March 2009 to February 2010 at two stations selected in the upstream and downstream of the Kürtün Dam. It was concluded that the Kürtün Dam Lake had a high-quality water in terms of T, pH, DO, COD, NH4 +–N, NO2 ?–N and NO3 ?–N values, but slightly polluted water with respect to TKN, PO4 3?–P, and MBAS according to the Turkish Water Pollution Control Regulation. The dam improved the stream water quality by increasing the DO concentration, and decreasing the NO2 ?–N and PO4 3?–P concentrations thanks to its hydraulic residence time despite the wastewater discharge by the nearby settlements. However, the wastewater discharge deteriorated the stream water quality increasing the COD, NH4 +–N, NO3 ––N, and TN concentrations.  相似文献   

3.
As a kind of slim shell structure flexibly based on its deformable foundation, high concrete arch dam exhibits remarkable spatial–time characteristics. In this paper, the Xiaowan Hydropower Project accommodating 294.5 m high double curvature arch dam is taken as example, to which the factor of time is introduced in the whole numerical simulation procedure. The dynamic inputting of the parameters related to the structural geometry and material properties (e.g. thermal, permeability, deformation/stress) following the construction progress is realized in an intension to establish a four-dimensional (spatial–time) numerical simulation procedure. The Digitized System of Xiaowan Arch Dam (DSXAD) is further formulated by the combination of the instrumentation system, the spatial–time simulation procedure, and the engineering judgments. The DSXAD has been working well in tracing the real working status of the dam during its construction period as well as service period. A series of difficult technical issues in the construction of the Xiaowan Dam are successfully solved with the help of the DSXAD. Through this practices important theoretical insights are achieved, which founds a new landmark for the high arch dam construction in China.  相似文献   

4.
Kallen  D  项伟  Ehret  D  Rohn  J 《中国地质大学学报(英文版)》2006,17(2):158-162
INTRODUCTIONLandslides annually cause a great amount of cas-ualties withinthe Chinese population and great lossesin the Chinese economy . The number of casualtiesreached 232 killed and 2 missing people in 2003 and283 killed and 69 missing people in 2004 . The eco-nomic losses amount to a total of 730 billion US $in2003 and 475 billion US $in 2004 (Zanetti ,2005 ,2004) .The DAAD (German Academic Exchange Serv-ice) is financing a project to investigate landslides .The project is a coo…  相似文献   

5.
Discharge of wastewater from the retaining pond of a Pb ore-flotation plant since 1967 and breaching of the retaining pond in April 1998 contaminated 17540 cbm of river bank sediment with 833 ton Pb, nearly 19 km along the Khli Ti Creek. High blood Pb concentration was detected in many inhabitants. Prohibition of water and aquatic biota consumption has caused difficulties for rural people to make their ends meet. The governmental agency closed the ore-floatation plant and built 2 rock check dams downstream. The dam was designed to slow down water velocity and precipitate particulate matter. Contaminated sediments that have been trapped in front of the dam were planned to be dredged and disposed in landfill. Until now, no dredging is performed because some experts claim that dredging will resuspend the contaminated sediment into the water column, and fresh sediment deposited during periods of high flow will cover the contaminated sediment. The aim of this study was to evaluate the ability of the rock check dam to prevent the transportation of Pb-contaminated sediment in the Khli Ti Creek. Sediment located before and after the rock check dam and 2 km downstream were collected in September 2003 and May 2005. During September 2003, Pb concentrations in sediment deposited before and after the rock check dam and 2 km downstream were 48840, 53741 and 36020 mg/kg, respectively. These results showed that Pb-contaminated sediment was transported over the first rock check dam but still remained after the rock check dam. Result of May 2005 sampling also showed the same trend, although with different ranges due to seasonal variation, types of collected sediment, sample preparation and analytical techniques. Pb concentrations in sediment were 209684, 306775 and 33760 mg/kg, respectively.  相似文献   

6.

With the long-term operation of the project, the material parameters of concrete-facing sand–gravel dam will change, which brings great difficulty to the scientific and effective stress and deformation analysis. Combining with the measured displacement data, the finite element analysis model of the concrete-facing sand–gravel dam of Heiquan reservoir was established, and the modulus of elasticity and internal friction angle of the dam body were inverted by the measured displacement of the dam, then the simulation analysis of the filling construction process and the reservoir storage process of dam was carried out, and the stress and deformation values of the dam during the construction period and the impoundment period were calculated. The results showed that the parameters obtained from the inversion are smaller than the original parameters, but there is little difference between them. The displacement calculated by finite element inversion was close to the measured displacement value, the overall displacement and stress distribution of the dam body and panel were in line with the general law, and the calculated displacement and stress values were at the normal level. This study provides a reference for parameter inversion and stress and deformation analysis of concrete slab dam through monitoring data analysis.

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7.
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8.
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9.
《Geodinamica Acta》2013,26(3-4):317-331
The Küçük Menderes Graben (KMG) is part of the horst-graben system of southwestern Anatolia (Turkey), bounded by the Bozda? horst in the north and the Ayd?n horst in the south. The Plio-Quaternary evolution of the KMG has been evaluated using the nature of the Miocene-Quaternary fill sediments and palaeostress analysis of slip data measured in different parts of the graben.

The graben is composed of five subbasins—the Kiraz, Ödemi?, Bay?nd?r, Da?k?z?lca-Torbal? and Selçuk—that are connected to each other through narrow Quaternary troughs. The Da?k?z?lca, Kiraz and Selçuk basins bear Miocene and younger sequences whereas the other subbasins are largely filled by Quaternary sediments. The maximum thickness of the Quaternary fill reaches about 270 m in the Ödemi? and Bay?nd?r subbasins.

The calculated slip results indicate multidirectional extension, three successive deformational periods, and possible counterclockwise rotation in the KMG during the post-Miocene period. The first phase was a strike-slip regime under N-S compression, followed by a second phase of deformation which resulted in ENE-WSW extension with strike-slip components. The final phase of deformation was NE-SW extension which constituted the final evolution of the KMG.

The graben gained its present morphological configuration via the onset of E-W-trending, high-angle normal faulting imposed on the regionwide synformal structure during the Plio-Quaternary. The KMG evolved as a result of rifting during the Plio-Quaternary which followed Late Miocene unroofing of the Menderes Massif and the evolution of the Büyük Menderes and Gediz grabens.  相似文献   

10.
As one of the world’s largest hydropower projects, the Three Gorges Dam (TGD)’s 156–175 m height storing test in flood recession seasons during 2006–2011 has aroused international attention. The novel approaches of cross-wavelet transform and wavelet coherence were firstly introduced to reveal the significant coherence and time lag property in time–frequency space between river dynamics in hydrological stations along Yangtze River. Then, using the optimum lag time nodes, corresponding regression models between river dynamics in these stations were established and utilized to assess the river dynamics in stations downstream under the impact of TGD’s impoundment. Results showed that the average decrease ratio of 24.3 % in the Three-Gorge reservoir outflow was caused in TGD’s impounding periods during 2006–2011. The corresponding average decrease ratios of 25.1, 16.5 and 1.9 % in Yichang flow, Datong flow (with 6 days lag), and estuarine Santiao river stage (with 32 days lag), respectively, were caused by TGD’s impoundment during 2006–2011. In addition, the impact weights of multiple driving factors on estuarine river dynamics were discussed, and the main factor of the combined impacts of estuarine tidal fluctuation and sea level change while the secondary factor of the upper stream inflow were demonstrated. A further suggestion about the optimization design of TGD’s safety impounding scheme was proposed to prevent estuarine saline water intrusion by guaranteeing the average daily increase of Three Gorges reservoir water level lower than 1.11 m/day during TGD’s impounding period.  相似文献   

11.
Volcanic activity in the Ayas-Güdül-Celtikci region began by Oligocene (?)-early Miocene time and persisted until the end of early Pliocene time. It commenced with andesitic breccias and lavas at the base of the series and evolved through the deposition of ignimbritic and laharic volcanic material toward intermediate levels of the succession. Caldera formation followed this period of volcanic activity. Ephemeral lakes covering the region caused the subaqueous extrusion of the latest lavas during this period of activity. Afterward, limnic and fluvial sedimentation Occurred in the region during a period of volcanic quiescence. This mid-late Miocene deposition was followed by new basaltic activity. The volcanism was controlled by conjugate fault sets, N45W and N15E, representing pure-shear stress in a N20W direction, from the late Oligocene to the end of the early Pliocene. Normal dip-slip faults having a N55E trend were created by local N25W tension, presumably because of the North Anatolian fault, after early Pliocene time.  相似文献   

12.
China has become the biggest CO2 emitter in the world. In China, economic development in different regions is not the same. Thus, it is necessary to study the regional decoupling relationship between energy-related CO2 emission and economic development. Considering the regional difference of economic development, energy consumption and CO2 emission, provincial regions in China are divided into seven economic bands. The Tapio decoupling method is adopted to calculate the decoupling index in the seven regions over the study period 1996–2013. Furthermore, the WCDM is developed to study the driving factors governing the decoupling state. The result showed that decoupling development differed in each economic band; North-East and North-West, showed a better trend and a worse one, respectively, than the others. Economic factor showed a stable trend of negative effect, and energy intensity factor was the crucial factor to accelerate the process of CO2 emission decoupling. Only in Yangtze River delta, economic band had structural factor shown a positive effect during the research period, and emission efficiency factor was not stable and showed a negative effect in most years in every region.  相似文献   

13.
Rock fall is a common natural hazard causing significant damage to infrastructure and loss of life and property. This paper describes selection of prevention method, construction processes and the results of a rockfall hazard assessment for the village of Sarica (Gürün region, Turkey) based on an engineering-geological model. The study area is located on the lower parts of an area with very steep cliffs and 40-500 slopes with fractured sedimentary and volcanic rocks. Detailed studies have been conducted in the region to prevent the risk of any rockfalls. Maps and charts are prepared including the rock blocks that are likely to fall and the related housing area under the risk. It was found that block sizes reached 3 m3. Rockfall analyses were performed along the selected profiles using the Rocfall V.5.0 software. Kinetic energy, bounce height, horizontal location of rock end-points and velocity of the rocks along each section were evaluated separately for each profile. This data was used to select design and construction of rockfall preventing system. In this study professional type rock fall barrier (catchment fence) was used. This method was chosen because it was cheaper, more practical and reliable than others.  相似文献   

14.
Because of their sensitive structure, earth dams might face failure due to seepage phenomenon. In order to prevent such failure, some equipment like piezometers are installed in the body or foundation of earth dams. This study investigated the importance of piezometer installation level in dam body or foundation using mutual information–wavelet–Gaussian process regression. 27 Piezometers in three section along with reservoir level were employed to predict one-step-ahead seepage discharge of Zonouz earth dam. The daily data of 1 year of piezometer level and reservoir level were collected for this purpose. In order to find the best possible input combination, three groups of modeling scenarios were defined using piezometers and reservoir level time series. As some input combinations had more than two variables, decomposed time series were imposed into mutual information (MI) tool in order to decrement input variables and find the most correlated input–output features. Afterward, mentioned features were imposed into optimized Gaussian process regression (GPR) to be predicted. Different kernels were selected as core tool of GPR, but results demonstrated the capability of radial basis function (RBF) kernel. GPR–RBF structure were optimized using cross-validation technique. Results indicated that input combination including piezometer level and reservoir level of section II, especially piezometer 203 time series led to the best result among all scenarios.  相似文献   

15.
The Burdigalian mixed siliciclastic–carbonate deposits of the Dam Formation are well-exposed in Al Lidam area, in the eastern province of Saudi Arabia. They represent a shallow part of the Arabian plate continental margin. The Dam Formation is correlatable to the Miocene reservoirs in both Iran and Iraq. Therefore, studying the Dam Formation lithologic heterogeneity in a small distance with high resolution could help in further work related to pattern prediction of the Miocene reservoir properties. High-resolution sedimentological investigation was carried out through six outcrops. The facies parameters (lithology, sedimentary structures, main fossils, paleocurrent patterns and geometries of the sedimentary bodies) were described. The results revealed 15 lithofacies that have been further grouped into 7 lithofacies associations 5 of which are carbonates and include (1) interbedded dolostone and evaporates, (2) microbialite buildup, (3) ooid-dominated grainstones, (4) burrowed skeletal peloidal wackestone–packstone and (5) mollusc-dominated wackestone–packstone. The remaining two associations are of siliciclastics and include (6) intertidal siliciclastics and (7) wave-dominated siliciclastics. These lithofacies were interpreted to reflect deposition in a mixed siliciclastic–carbonate ramp system that includes subtidal, shoreface, intertidal, foreshore, supratidal and estuarine deposits in a shallowing-upward succession. Each one of these lithofacies association has distinct geometry and architecture pattern. Oolites and heterozoan lithofacies occur as sheets and show great continuity along the strike direction. Oolites pass laterally in the dip direction into more skeletal- and peloid-dominated zones, whereas heterozoan lithofacies stay continuous in the dip directions and change from siliciclastic to carbonate heterozones. In contrast, microbialite lithofacies lack continuous beds and occur as localised bioherms and biostroms. Channelised lithofacies are restricted laterally into isolated channel bodies and vertically in the contact boundary between siliciclastic and carbonate lithofacies, whereas the interbedded dolostone and evaporite lithofacies form distinct, relatively thick continuous layers. With continuous exposures in both strike (1.2 km) and dip (0.15 km) directions, the outcrops in the Al Lidam area provide unique opportunity to study the heterogeneity among lithofacies of the mixed siliciclastic–carbonate system of the Dam Formation. Such study may provide insights to predict occurrence and distribution of lithofacies bodies in their equivalent reservoirs which are important for reservoir characterisation.  相似文献   

16.
The physical (turbidity, color, smell, taste, pH, and conductivity) and geochemical properties (Ca, Mg, Na, Fe, Mn, Al, K, Cl?, HCO3 ?, SO4 2?, Fe, Cu, Co, Ni, Zn, Cd, Pb, and Cr) of the drinking water in Gümü?hane city center were determined. This city center constitutes the study area. The pH levels of the water samples ranged from 6.3 to 8.2, and their conductivities ranged between 240 and 900 μS. These findings were concordant with the drinking water standards of the Turkey Standard Institute and the World Health Organization. The hardness of the water samples in the study area was between 18.1 and 115.1 °Fr. These samples were classified as extremely hard, hard, and quite hard. In addition, an assessment using the criteria for Inland Surface Water Classification indicated that considering certain parameters (pH levels, amount of Na, SO4 2?, Fe, Mn, Al, Co, Ni, Cu, and Cr), the samples belonged to class I (high quality) water. When Cl? amount and conductivity were considered, the samples belonged to the first and second classes (less polluted) of water. The water in the study area was generally classified as carbonated and sulfated (Ca + Mg > Na + K) water classes. This water contained more weak acids than strong acids (HCO3 ? + CO3 2? > Cl? + SO4 2?). The pH levels (6.3–8.2) of the water in the study area were unrelated to the varying concentrations of metals in the water. Elements such as Fe, Ni, Cd, Pb, Zn, and Cu increase in the water through the water–rock interaction in the area in which water rises or through the mixture of water with either mine or industrial wastes. In addition, several water samples belonged to an acceptable water class for drinking and usage.  相似文献   

17.
River restoration through dam removal provides an opportunity to investigate the changing nature of environmental conflicts and politics in long-humanized landscapes. In New England, where over 14,000 dams fragment the region’s rivers, dam removals are often highly contested. This is due, in part, to how the intertwined roles of history, identity, and aesthetics coalesce to create attachment to place and inspire the defense of dammed landscapes. Dam removal provides a useful lens to consider the following: How do the historical and geographical contingencies of this region shape and alter conflicts over dam removal in specific ways? In instances where conflicts emerge, what do the conflicts reveal about the politics of ecological restoration in highly altered landscapes? We use a political ecology approach to reveal how complex cultural dynamics, competing interpretations of science and the environment, micropolitics, and the role of multiple actors generate and shape conflicts over dam removal. We show that the historical geography of New England influence conflicts over removal in important ways, particularly with regard to the roles of aesthetics and identity in landscapes that are characterized largely by consumptive as opposed to productive uses. Our findings also suggest that restoration in long-humanized landscapes will embroil new constellations of human and nonhuman actors, requiring attention to the political and cultural, as well as the ecological, dimensions of restoration. This paper contributes to research on the political and social dimensions of dam removal, as well as to research at the nexus of ecological restoration and environmental politics.  相似文献   

18.
In the present paper the results of experimental and numerical investigations of hygro-thermo-mechanical properties of “Schilfsandstein” from Baden-Württemberg are presented and discussed. The aim of the study was to investigate the influence of extreme environmental conditions causing severe damage that can often be observed on various monuments during restoration and reconstruction process. In the experimental investigations the stone specimen was exposed to extreme hygro-thermal conditions, which caused significant damage (cracking). During the experiment the ultrasonic and acoustic emission analyses were performed. Subsequently, a 3D finite element analysis was carried out using a coupled hygro-thermo-mechanical model for stone. The experimental and numerical results indicate that wetting in combination with either decrease or increase of temperature lead to severe damage. The most critical locations for initialization of cracks are sharp spikes (notches), or acute angles that are inward or outward oriented (corners). Stiff but brittle layers, like late diagenetic iron cementations, might be a weak point for the initialization of crack. Furthermore, the bedding direction (anisotropy) seems to be a preferred direction for crack propagation. The results of the numerical analysis are in relatively good agreement with experimental observations.  相似文献   

19.
The seepage occurrence from the reservoir on the right bank of the Akde?irmen Dam located in Afyonkarahisar province in the Turkey has been investigated. When the reservoir began to fill with water, a large amount of water seepage occurred at the dam. The seepage developed at the base of the spillway and the right downstream slope of the dam. The various attempts have been made to reduce the seepage using grouting. Although the additional grouting operations was reduced the seepage at the base of the spillway, there has not been a reduction in seepage at the water outlet location at the downstream slope. Electrical resistivity measurements along the eight lines with the dipole–dipole array and dye tracer tests were performed in order to identify the seepage locations. The interpretation of electrical resistivity data showed the distribution of strata and the seepage zone along the right downstream of the dam. Groundwater flow rates calculated from dye tests indicated that there is an excessive seepage south-eastwardly on the downstream slope of the dam. Integrated interpretation of resistivity data and dye tests indicate that the seepage paths are in the direction from NW to E and SE.  相似文献   

20.
The mineralogy of the Istala deposit, Gümüşhane, northeastern Turkey, was studied in detail, and a geochemical investigation was carried out using electron probe micro-analysis (EPMA). Sphalerite, galena, chalcopyrite and pyrite are the major sulfide minerals found in the Istala deposit, with minor amounts of bornite, idaite, tetrahedrite–tennantite, anilite, yarrowite, mckinstryite, covellite and chalcocite. In addition to these, barite and a small quantity of quartz occur as gangue minerals. Based on the textural relations and mineral assemblages, five different stages of crystallization have been recognized. Mineral paragenesis of the first four stages has been found to be similar, whereas clear enrichment has been observed in the modal abundance of the copper sulfide mineral assemblage at the fifth-stage ore formation. Whole-rock geochemical analyses of the Istala ore show an enrichment of Ag content up to 3328 ppm. Optical observations and EPMA study indicated that abundant silver mineralization was found in the Istala ore, especially during the later-stage ore deposition. Repetition to the presence of native silver in the samples, a significant amount of silver was incorporated in bornite, idaite, tetrahedrite–tennantite, anilite, yarrowite, mckinstryite, covellite and chalcocite, whereas a trace amount of silver has been detected in sphalerite, galena, chalcopyrite and pyrite. The homogenization temperatures (Th) of the primary fluid inclusions were measured between 98 and 284 °C, with frequency peaks around 140 °C, 190 °C and 240 °C. All data obtained support the theory that later stage copper-rich sulfides, formed under the low temperature conditions, are responsible for the large amounts of silver content in the Istala mine.  相似文献   

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