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81.
Settlement and slaking problems in the world's fourth largest rock-fill dam, the Ataturk Dam in Turkey 总被引:3,自引:0,他引:3
The Ataturk Dam is the fourth largest clay cored rock-fill dam in the world. Located in southeastern Turkey, it is the centrepiece of a project called the Southeastern Anatolian Project (GAP). The construction of the dam was finished in the short time of 3 years and 8 months in August 1990. As the reservoir level started to rise, settlement problems started to occur along the crest reaching considerable levels by May 1992 and the weathered vesicular basalt used in the rock-fill section of the dam started to slake seriously. The elevation of the crest has fallen down to such an extent that now the upper part of the dam is being reconstructed to the original height of 549 m in order to maintain the 7 m freeboard and keep the dam operational. The settlement and slaking problems of the dam were investigated both in the field and the laboratory using soil and rock mechanical techniques. Standard proctor tests were run to determine the optimum moisture content at which the highest dry density (best compaction) is obtained during compaction of the impervious clay core. Consolidation tests were performed on undisturbed compacted clay core samples to determine if the field compaction of the clay core was done to the standards determined in the laboratory. Unconfined compression tests were run on the two different (sound aphanitic and weathered vesicular) basalts used in the rock-fill section of the dam to determine their unconfined compressive strengths. Slake durability tests were run on the same basalts to determine their durability under wetting and drying cycles. Petrographic and X-ray analysis were done so as to study the mineralogical contents of the two basalts and in turn, to determine the cause of rapid slaking of the vesicular textured weathered basalt. The consolidation test results show that, the field compaction of the impervious clay core of the dam was not done to the standards determined through the proctor tests in the laboratory. The unconfined compressive strength of the sound aphanitic basalt is more than ten times greater than the weathered vesicular basalt, and while the former has extremely high durability the latter only has medium durability. Because of nontronite (iron montmorillonite) and secondary calcite amygdules filling the vesicles, the weathered vesicular basalt used in the rock-fill section is slaking badly causing additional settlement and landslides both in the clay core which is already settling and the rock-fill section of the dam. With the continuing slaking, the present reconstruction of the crest up to the theoretically intended height of 549 m to maintain the 7 m freeboard and keep the dam operational seems only to be a temporary solution. 相似文献
82.
We introduce a novel, time-dependent inversion scheme for resolving temporal reservoir pressure drop from surface subsidence
observations (from leveling or GPS data, InSAR, tiltmeter monitoring) in a single procedure. The theory is able to accommodate
both the absence of surface subsidence estimates at sites at one or more epochs as well as the introduction of new sites at
any arbitrary epoch. Thus, all observation sites with measurements from at least two epochs are utilized. The method uses
both the prior model covariance matrix and the data covariance matrix, which incorporates the spatial and temporal correlations
between model parameters and data, respectively. The incorporation of the model covariance implicitly guarantees smoothness
of the model estimate, while maintaining specific geological features like sharp boundaries. Taking these relations into account
through the model covariance matrix enhances the influence of the data on the inverted model estimate. This leads to a better
defined and interpretable model estimate. The time-dependent aspect of the method yields a better constrained model estimate
and makes it possible to identify non-linear acceleration or delay in reservoir compaction.
The method is validated by a synthetic case study based on an existing gas reservoir with a highly variable transmissibility
at the free water level. The prior model covariance matrix is based on a Monte Carlo simulation of the geological uncertainty
in the transmissibility. 相似文献
83.
84.
以国家自然科学基金为依托建立模拟实验区,探究不同施工机械和碾压次数下的土壤物理指标(压实度、容重、孔隙度、含水量、电导率和温度)的变化。研究结果表明:随土层深度的增加,压实度、容重和电导率逐渐递增,孔隙度、含水量和温度逐渐递减;随碾压次数的增加,压实度和容重逐渐递增,孔隙度逐渐递减,土壤含水量、电导率和温度先增加后降低,其中使用自卸汽车时,3次碾压指标值最高,使用履带式推土机时,5次碾压指标值最高,而使用履带式推土机的处理效果要好于使用自卸汽车;通过对各处理与对照间的拟合度分析发现,使用履带式推土机碾压5次的土壤中各指标与对照拟合度最高,表明采用"履带式推土机×碾压5次"的组合,复垦土壤中物理性质与正常土壤最为接近。 相似文献