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河床深厚覆盖层勘探取样与试验研究是我国西部水电工程勘察中最常见技术难题之一。金沙江乌东德水电站坝址区河床覆盖层厚度较大、成因多样、组成混杂、结构不均,高围堰与深基坑稳定问题突出。为此,作者所在单位开展了专题研究工作,在勘探取样技术与原位测试方法上进行了探索与创新为获得原状样而专门研制了单管与双管内筒式锤击取样器,为弥补钻探取样之不足而将可视化技术(如钻孔数字彩电、孔间电磁波CT)与常规物探方法(如地震法勘探、钻孔声波测试)相结合创新性开展原位测试,全面查明了河床覆盖层的组成及结构,开辟了河床深厚覆盖层地质勘察研究的新途径,不仅为河床深厚覆盖层工程特性室内试验研究提供了前提,而且为高围堰与深基坑稳定问题地质分析、工程评价及设计处理提供了充分可靠的地质依据,可为类似工程地质勘察研究所借鉴。 相似文献
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金沙江中游上江坝址河床深厚覆盖层建高坝可行性探讨 总被引：2，自引：0，他引：2
摘 要 上江坝址为金沙江中游龙头水库的比选坝址之一,坝址河床覆盖层最厚达206.2 m,在深厚覆盖层上修建最低249 m级的高土石坝,大坝规模达到甚至超过世界前沿水平,筑坝技术难度大。通过测绘、钻探、物探、物理力学测试等工作揭示:(1)河床覆盖层由漂卵石、低液限粘土、砾卵石、碎块石、砂砾石等组成;(2)河床覆盖层中各粗粒土强度相对较高,低液限粘土强度较低,为坝基一条连续完整的相对软弱带;(3)坝址位于龙蟠断陷盆地内,主要受新构造垂直差异运动的影响,河床接受金沙江上游及坡体上物质堆积,逐渐形成了现今的深厚覆盖层。初步研究本坝址在河床覆盖层上建高土石坝是可行的,但需要对坝基采取工程处理措施。探讨了不同建坝方案所引发的工程地质问题,为筑坝技术研究提供了地质依据。 相似文献
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在西部山区水利水电勘探中,采用轻型钻机钻进深厚覆盖层,并成功采集岩心是一项技术难题。钻进深度越大,越易产生坍塌、埋钻等事故,因而成孔极其困难。根据目前西部水利水电勘探的常用设备,采用轻型钻机,合理设计钻孔,并对泥浆护壁方法进行改进,使钻孔成功达到预定深度。应用结果表明：轻型钻机钻进深厚覆盖层时,孔身设计分为4级变径;深度70 m以浅采用硬质合金钻头,深度70 m以深采用孕镶金刚石钻头,钻进稳定;SM-KHm超低固相泥浆护壁,不仅环保而且节水,可有效保护孔壁稳定,防止塌孔;岩心采取率达到95%以上,钻孔最大钻进深度达到223.54 m,有效突破了轻型钻机的最大钻进深度,为轻型钻机钻进西部山区深厚覆盖层及取心提供重要的技术参考依据。 相似文献
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青藏高原南缘某拟建机场场区发育第四系深厚覆盖层,对该工程建设具有较大的制约作用。钻孔资料显示,该深厚覆盖层普遍分布于整个场区,厚度均在30m以上,最大孔深105m仍未揭穿。纵向上深厚覆盖层由上而下可划分为4层:全新世泥石流堆积层(Q4sef)、全新世冲洪积堆积层(Q4al+pl)、全新世湖相堆积层(Q4l)和晚更新世冲洪积堆积层(Q3al+pl)。其中:泥石流主要由角砾和碎石组成,最大厚度约13m,分布于研究场区西侧;全新世冲洪积层组成物质复杂,以粉细砂和圆砾居多,无明显分层规律,最大厚度约7m;湖相沉积粉质黏土呈可塑-流塑状,局部夹含砂,最大厚度约43m;晚更新世冲洪积层以细砂和中粗砂为主,局部夹有卵砾石,厚度大于42m。分析表明,深层覆盖层成因与晚更新世以来喜马拉雅快速隆升及间冰期气候密切相关,而表层覆盖层与全新世以来青藏高原气候回暖及短期冷暖交替气候密切相关。试验揭示深厚覆盖层物理力学性质差异明显,研究场区存在不均匀沉降、渗漏破坏、边坡稳定性及冻融诱发地基破坏等主要工程地质问题。 相似文献
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西藏雅鲁藏布江成矿区矿产资源评价新进展 总被引：29，自引：5，他引：24
雅鲁藏布江成矿区位于青藏高原腹地,目前是中国西部地区地质工作程度极低的地区之一,但成矿条件十分有利。近年来中国地质调查局在该成矿区部署的“雅鲁藏布江成矿区铜多金属资源调查评价”项目取得了一些重要进展,目前已控制了4个大型铜矿床、1个大型铅锌矿床、3个大型富铁矿床的雏形,新提出了一批可供进行预查或普查的新矿产地,中国西部又一大型铜、铁、多金属矿产资源基地的前景在西藏已经初步显现。 相似文献
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前言珠穆朗玛峰地区系指西藏雅鲁藏布江以南,亚东以西,吉隆以东的我国境内广大地区。在解放以后,曾有多次科学考察,尤其在1966年至1968年,由中国科学院组织西藏科学考察队,对这一地区进行了大规模的多学科考察。 相似文献
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Ghodrat Barzegari 《Geotechnical and Geological Engineering》2017,35(3):991-1011
Since every dam site is unique and different from the rest, special geological and geotechnical investigation for each dam is a key factor in the success of the project. The Peygham-chay is a 55 m in height is an embankment dam with a clay core that is situated to the northwest of Iran and is under construction at present. The dam is founded on a valley filled by 12 m alluvium deposits that thicknesses increase toward left abutment up to 60 m. The dam site investigated based on surface discontinuity surveying, drilled boreholes logging data, in situ and laboratory tests. Detailed and extensive surface and subsurface explorations have been carried out at the dam site to characterize the geotechnical properties of foundation. The geology of the site consists of a series of cretaceous basic lavas intrusion composed with andesite, basalt and diabase that cropped out on the right abutments and is strongly fractured due to numerous joints and faults. Permeability of fissured rock mass is strongly depends on joint properties (degree of jointing, opening, continuity, filling material and weathering). In this paper in situ permeability of foundation was evaluated based on water pressure tests (lugeon) results and secondary permeability index (SPI). The impact of water pressure on joints characteristics and consequently flow rate are investigated and considered in the results. The overall groutability of rock mass was evaluated by comparison of RQD as an index of rock jointing degree and SPI values. The results indicated that permeability of rock mass in more than 66% of the tests is very low and not required for treatment. Meanwhile in the rest of sections the construction of preferred sealing system in necessary. 相似文献
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Sedat Türkmen Hidayet Tağa Eray Özgüler 《Geotechnical and Geological Engineering》2013,31(4):1137-1149
This paper covers the investigation of construction materials and selection of the dam type for the Büyük Karaçay Dam, which was planned to be constructed on Büyük Karaçay River 20 km to the SW of Hatay (Southern Turkey). The purposes of the dam are irrigation, domestic water supply, and producing energy. Auxiliary structures locations have been determined during the study of detailed geological maps of the dam axis and reservoir area. Quality, quantity and hauling distance of natural construction materials were effective to select different dam types. For engineering geological studies exploration boreholes were drilled at the dam site; pressuremeter tests were performed in order to determine bearing capacity and elasticity properties of rocks; pressured water tests were also performed to determine permeability of the dam site. Moreover, physical and mechanical properties of rocks were determined by the laboratory test. In the feasibility stage, the dam type was chosen as the central core rock-fill dam, depending on state of natural construction materials. In design stage dam type was changed as faced symmetrical hardfill dam. Finally, the dam type was revised again during the design stage as concrete face rockfill dam. 相似文献
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In this study, seepage phenomena through the right abutment of Shahid Abbaspour dam are investigated. The Shahid Abbaspour dam is a 200 m high arch dam, which regulates the waters of the Karun River, serves power generation, and flood control and irrigation needs. The dam site lies in the Zagros Mountains of southern Iran. This region presents continuous series of mainly of karstic limestone, marl, shale and gypsum ranging in age from Jurassic to Pliocene. The region has subsequently been folded and faulted. Seepage from the Shahid Abbaspour reservoir occurs mainly through the karstic limestone.The basic foundation treatment of the dam consisted of consolidation grouting, a high-pressure grout curtain and a drainage curtain. Moreover, a 144 m high and 30 m wide concrete cutoff wall was built to prevent reservoir seepage through a clay-filled fracture zone in the right abutment. The grout curtain penetrates the “Principal Vuggy Zone” only beneath the central portion of the dam and below the cutoff wall. In the right abutment fan curtains were constructed to reduce drainage flows, but the seepage problem could not be solved. In order to determine the seepage direction and karstification pattern, hydrogeological studies have been carried out. Additional investigation boreholes have been drilled to monitor fluctuations in groundwater level. Besides these, water chemistry, dye tracer, pinhole and XRF tests have been carried out. As a result of these studies, seepage paths have been identified in the karstic limestone in the right abutment of the dam. 相似文献
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西南某水电站坝址基岩为碳酸盐岩,坝区断层构造和岩溶较发育。水库蓄水后,坝址右岸抗力体1 315 m排水洞出现持续渗漏。随库区水位升高,涌水量逐渐加大至约1.9 m3·s?1,水库无法正常蓄水。为查明库水渗漏途径,有针对性地采取措施减少渗漏量,开展了岩溶渗漏研究。通过工程地质测绘、岩溶水文地质调查、钻探、压水试验、孔内电视、孔内电磁波CT等勘察手段,结合前期平硐、基坑开挖和物探等勘查成果,并利用灌浆孔灌浆过程试验数据,最终查明库水渗漏通道:在水压力作用下,库水沿断裂构造F12下渗,在深部沿层间溶蚀带绕过防渗帷幕,呈30°倾角向下游逐步抬升,最终通过竖向岩溶发育带,从1 315 m排水洞地质薄弱点涌出。通过对灌浆帷幕采取补强措施,封堵了主要渗漏通道,库水渗漏得到有效控制,达到了设计要求。 相似文献
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The Doosti Dam was built across the Harirood River on the border between Turkmenistan and Iran. During the reservoir impounding, leakage occurred as new springs through the sandstone layers of the Pesteleigh Aquifer and limy sandstone and limestone layers of the Neyzar–Kalat Aquifer, at the right abutment of the dam. To evaluate the grout curtain operation, a tracer test was carried out by injection of Uranine in a borehole located at the upstream of grout curtain in the Pesteleigh Aquifer. Tracer test results demonstrated a diffuse flow component through the grout curtain in the Pesteleigh Aquifer, but no tracer was detected at the main leakage point, SP1 Spring, emerged downstream of grout curtain from the Neyzar–Kalat Aquifer. Using the spectral coherency function, the lag time between changes in the water level of the injection borehole and water level in the tracer detected boreholes or discharge of the tracer detected springs was determined. Linear regression analyses indicated that the estimated lag time by the time series analysis was close to the first arrival time of the tracer. Therefore, the estimated velocities based on the lag time of time series could be considered close to the calculated velocities based on the first arrival time of the tracer. The estimated groundwater velocities based on the time series analysis ranged from 3.91 to 20.31 m h?1, showed that diffuse flow dominated pathways from the reservoir toward the downstream boreholes in the Neyzar–Kalat Aquifer, while conduit flow was present within the pathways toward the SP1 Spring. Regarding the reservoir volume, the negligible amount of leakage at the maximum water level of the reservoir confirmed well overall operation of the grout curtain at the dam site. 相似文献
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In this paper, flood problems in India, regional variabilityof the problem, present status of the ongoing management measures, their effectiveness and futureneeds in flood management are covered. Flood problems in India are presented by four zonesof flooding, viz. (a) Brahmaputra River Basin, (b) Ganga River Basin, (c) North-WestRivers Basin, and (d) Central India and Deccan Rivers Basin. Some special problems,related to floods like dam break flow, and water logging in Tal areas, are also mentioned.Progress of various flood management measures, both structural and non-structural, arediscussed. In addition, future needs to achieve efficient and successful flood managementmeasures in India are also pointed out. 相似文献
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Comparison of Permeability and Groutability of Ostur Dam Site Rock Mass for Grout Curtain Design 总被引：3，自引：1，他引：2
The focus of this study is the empirical hydromechanical behaviour of the Ostur dam site rock mass. The area surrounding the dam mostly consists of diorite and andesite, with primary fractures and hydrothermal veins. The hydromechanical behaviour of the rocks was determined using 500 water pressure tests at 5-m intervals. The hydrothermal veins and 2,739 discontinuities were studied and mapped along the dam axis. As a result, it was possible to design an optimum grout curtain for the dam axis. The empirical hydromechanical behaviour of the rock was studied to determine water flow and grout pressurised flow during the field tests that were conducted on two representative A-series grouting operation boreholes (one borehole for each abutment). The secondary permeability index (SPI), Lugeon value (LU), rock quality designation (RQD) and cement take (CT) values are presented and compared in this article. It is concluded that permeability and groutability are mostly controlled by the specifications and characteristics of the veins, especially in shallow areas and lower depths. A procedure is proposed based on a comparison of the trends in the RQD–SPI and LU–CT, and it is suggested that the areas with diverging trends require no treatment and that those with converging trends require heavy treatment. Additional complementary studies that were conducted during the construction stage have validated these results. 相似文献
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王宇飞 《地质灾害与环境保护》2010,21(2):40-43,63
喜河水电站坝型为混凝土重力坝,重力坝对地基岩体的抗剪强度有较高的要求。前期勘查成果表明喜河水电站坝址区存在较多的缓倾角结构面,缓倾角结构面的存在是影响坝基抗滑稳定的关键,因此要对坝基作出抗滑稳定性评价。首先要研究坝址区缓倾角结构面的分布规律及连通情况,通过对坝址区缓倾角结构面的综合分析研究提出合理的坝基岩体的综合抗剪强度。 相似文献
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Integrated use of hydrochemistry and resistivity methods in groundwater contamination caused by a recently closed solid waste site 总被引：6，自引：0，他引：6
In order to investigate the groundwater contamination by solid waste disposal using both hydrochemical and geophysical methods,
the Halkalı (I˙stanbul) solid waste disposal site which was closed in 1994 was investigated. The disposal site lies on a ridge
between two valleys filled with alluvium. A total of six boreholes were drilled on two lines across the Menekşe valley adjacent
to the Halkalı site. Groundwater samples collected from these boreholes were analyzed for various contaminant parameters.
The results indicate that TDS and chloride concentrations decrease horizontally away from the waste site whereas they increase
with depth. Electrical soundings carried out at 12 locations yielded high resistivity values at the upstream part of Menekşe
valley while lower values were obtained from the locations near the leachate seepage points.
Received: 11 November 1997 · Accepted: 23 February 1998 相似文献