门头沟校区拟建场地地质灾害危险性评估

采空区是一种潜在而特殊的地质灾害,会引发地面变形、下沉、塌陷等环境问题,严重影响着人们的生产生活,在采空区场地进行棚户区改造和配套教育设施建设,首先必须对地质灾害的危险性进行科学评估。本文以北京景山学校门头沟校区拟建场地为研究区,开展地质环境条件和地质灾害现状调查,分析评价地质灾害的危害范围和程度,以及对场地和建筑物的影响。研究结果表明,该区的主要地质灾害为采空塌陷和不稳定斜坡,中南部局部区域为地质灾害危险性等级“大级”地段,同时给出了场地的适宜性评价,提出了相应的防治措施,为场地开发建设提供了决策依据。     

Geological and geotechnical characteristics of Karameh dam site, north of the Dead Sea, Jordan

This paper describes a feasibility stage geotechnical evaluation carried out at the Karameh dam site. The 45 m high, 2,150 m long dam will be built across the Wadi Mallaha on Quaternary lacustrine deposits and store fresh water from the King Abdullah Canal. A confined highly saline aquifer was identified at a depth of 25 m, the saline groundwater migrating naturally through the Lisan Formation. Stability analysis of the foundation indicates that the slopes are just stable under dry conditions and may become unstable under wet conditions. The most important problem is the presence of the active main Jordan Valley Fault crossing both the dam body and reservoir. Electronic Publication     

埃塞俄比亚北部特拉喀密提VMS型铜锌多金属矿床地质特征与找矿标志

特拉喀密提铜锌多金属矿位于埃塞俄比亚北部成矿带矿产富集区,区内已发现与海相火山作用有关的块状硫化物矿床(点)6处。文章在野外地质调查和找矿勘查成果的基础上,结合收集到的地质矿产资料,系统地总结论述了特拉喀密提铜锌多金属矿地质特征、找矿标志,探讨了矿床形成环境、成因类型,认为该矿床属于黑矿(Kuroko)型VMS矿床,为该地区成矿预测和地质找矿提供了理论依据。     

Geotechnical characteristics of Bakhtiary dam site,SW Iran: the highest double-curvature dam in the world

The Bakhtiary Hydropower Project with a 325 m high dam will be constructed on Bakhtiary River, in southwest Iran. The main dam has been designed as a double-curvature concrete structure which will be the highest one of its type in the world. Geologically, the dam site is located on siliceous limestone of the Sarvak Formation in the northwestern part of the folded Zagros. A large number of complicated geological structures in the study area, such as folding and duplex structure, faults, chevron folds, kink band zones as well as joint and fracture systems, raised concerns regarding the acceptability of the site for such a monumental dam. To create a comprehensive geotechnical model of the dam site and appurtenant structures, very extensive surface and subsurface investigations were carried out, including core drilling, water pressure testing, driving exploratory galleries for engineering geological mapping, a rock mass discontinuity survey and in situ rock mechanical tests. This research applies the results of the engineering geological and geotechnical investigations to define the geomechanical model of the dam site enabling options to be considered to achieve a safe dam design. The investigations show the rock mass of the dam site area is intersected by four main discontinuities namely, the bedding plane(s) of the rock mass and three major joint sets. Water pressure tests provide data about the permeability of the rock mass which is significantly dependant on the joint properties and the geological structures. These parameters, set the criteria for the design of the grout curtain at the dam foundation. The rock mass classification of the dam site was determined mainly based on the gallery survey and core logging using the rock mass rating, geological strength index (GSI) and Q system. Six classes of rock mass qualities were distinguished which show a fair to good rock mass at the dam foundation. From the plate load test results, a site-specific correlation was developed for estimating the modulus of deformation of the rock masses using GSI value. The estimated engineering geological and geotechnical parameters at the dam site are generally favorable and suitable for the safe design of the Bakhtiary arch dam with a height of 325 m.     

Engineering geological appraisal of the Sulakyurt dam site,Turkey

This paper discusses the engineering geological investigations, diversion tunnel support design and slope stability assessment studies carried out at the Sulakyurt dam site, northeast of Ankara, Turkey. The Sulakyurt dam will be used for flood flow control and water storage for irrigation. Engineering geological mapping, discontinuity surveys, core drilling, water absorption and laboratory tests were undertaken. The RMR, Q and GSI approaches were used to estimate the rock mass quality, site characteristics, rock mass parameters and appropriate tunnel support elements. The results of kinematic and limit equilibrium analyses for the slopes on the right and left banks are reported.      

埃塞俄比亚北部阿斯格德地区地球化学异常特征与找矿意义

阿斯格德地区位于埃塞俄比亚北部提格雷州施瑞县境内,地球化学景观属半干旱中低山区,一、二级水系发育,以V型河谷为主,剥蚀区地形平缓,覆盖有残坡积物,适宜进行水系沉积物测量和沟系土壤地球化学测量。通过地球化学普查工作,在该区圈定水系沉积物组合异常27处,圈定沟系土壤组合异常19处。对4处组合异常开展了异常查证,发现铁帽型金矿点1处,构造蚀变岩型金矿点1处,铁帽型金矿化点2处,圈定找矿靶区4处,取得了较好的找矿效果,为后续矿产勘查工作及探索和建立境外矿产资源快速评价方法体系提供了依据。     

四川鸭嘴坝址右岸滑坡对坝址选择影响的分析

对四川凉山州鸭嘴河拟建鸭嘴坝址进行地质勘察之后,证实坝址右岸存在一个较大的基岩滑坡,预计在设计水库水位时,滑坡体将产生滑塌成为右岸的不稳定因素,从而使右坝肩存在稳定和渗漏等严重工程地质问题,故建议放弃鸭嘴坝址。     

Geological and geotechnical characteristics of Xiaolangdi dam, Yellow River, China

In order to construct a 154 m high, 1,650 m long earth filled dam across the Yellow River at Xiaolangdi, China, site investigations including in situ and laboratory tests, Landsat imaging, geological mapping, geophysical survey and drilling were undertaken. Two special investigation techniques were employed. To ensure full recovery of the intercalated clays and siltstones in the Permian and Triassic deposits, a sleeve drilling technique was introduced while to establish the long-term stress conditions in the tunnels, radial resistance testing was undertaken. The paper focuses on the geotechnical characteristics of the Quaternary sands and gravels, which in the channel of the valley are up to 70 m thick, and discusses the influence of the Triassic and Permian bedrock.     

Estimation of bearing capacity of basalts at the Atasu dam site,Turkey

This paper describes the results of the engineering geological investigations and bearing capacity studies carried out at the proposed site of the rock fill Atasu Dam, to be constructed on basalts and pyroclastics. Rock mass strength and modulus of elasticity of the rock mass were determined using the Hoek–Brown empirical strength criterion. Rock mass classifications for the dam rock foundation were undertaken following the RMR, Q and GSI systems and the stress distributions using the finite element technique. To estimate the bearing capacity of the basalts, different empirical equations were used and compared.      

Design and underground construction at the Xiaolangdi multipurpose dam site

The Xiaolangdi Multipurpose Dam Project on the Yellow River near Luoyang, Henan Province of the People's Republic of China, involves design and excavation of 19 water conveyance tunnels, several access tunnels, a large number ofgrouting and drainage adits, and an underground powerhouse complex. This paper describes some aspects relating to the design of excavation and rock support of the tunnels, varying in diameter from 8 to 18.5 m, and the powerhouse complex. The rock consists of interbedded sandstone, siltstone and claystone. Close to very widely spaced beddingplanes dip at an angle of 8° to 10°, towards east.     

Verifying the ground treatment as proposed by the Secondary Permeability Index during dam foundation grouting

Bulletin of Engineering Geology and the Environment - The Secondary Permeability Index (SPI) is a permeability-based rock mass classification, which when complemented with the degree of jointing...     

The effect of geology on the suitability of the Olynthios river dam site,Northern Greece

The paper draws attention to the adverse geological and tectonic setting for a proposed dam on the Olynthios river in Northern Greece. The preliminary investigation showed the foundation area to be at the boundary of two dissimilar units in tectonic contact: Mesozoic metamorphic strata juxtaposed with Neogene sedimentary strata. It discusses the significance of the conglomerates in the Neogene deposits and the importance of the clay lenses and clay matrix for the stability and potential settlement of the dam. Although numerous faults are present, the major faults dip steeply at right angles to the dam axis. The study has indicated that there is little loose disturbed material associated with the faults. In this particular environment, in addition to selective grouting, it is recommended that a clay blanket is placed upstream to lengthen the flow path. The feasibility study has shown that despite the theoretically unfavorable conditions the site can be considered suitable.      

Landslide characterization and distribution in northern Ethiopia: a case study from the Adishu area

Bulletin of Engineering Geology and the Environment - Landslides have resulted in large numbers of casualties and huge economic losses in the hilly and mountainous areas of the Ethiopian highlands....     

门头沟校区拟建场地采空区探查技术研究

采空区的存在不仅严重威胁着矿山的安全生产和附近居民的正常生活,而且还可能诱发地面沉降、地面塌陷等地质灾害,尤其是在其上方进行基础设施建设,更有必要对采空区的分布、位置、形态、大小及冒落等状况探查清楚。本文以北京景山学校门头沟校区拟建场地为研究区,从“探”和“查”两个方面开展工作,基本查明了采空区的分布情况。通过地球物理探测,推测出6处采空区异常区域,经过钻探工程验证与详细勘察,12个钻孔中发现了采空区或采后虚填物空洞,同时分析了场地的稳定性和抗震性,为场地开发建设及其安全性提供了设计和决策依据。     

Investigation into in situ stress fields in the asymmetric V-shaped river valley at the Wudongde dam site,southwest China

The Wudongde Reservoir, now being constructed on the lower reaches of the Jinsha River, will be the forth largest hydropower plant in terms of capacity in China. This project includes a concrete arch dam and two large-span underground caverns in both abutments. For their design and construction, in situ stress measurements and geological survey were conducted. In this study, following an introduction of the geological conditions and topography, an interpretation on the test results of in situ stresses is presented for clarifying the distribution features of natural stresses in the engineering area. It is interesting to find that the vertical stress is predominant in the project area and that the horizontal stress reduces largely in the relaxation zone near the bank slopes, while concentrates at the valley bottom and becomes normal in the depth of both abutments. Also analyzed are the effects of valley topography, geological conditions in the project area as well as the macro-regional tectonics on the distribution of in situ stresses at the dam site. A noteworthy finding is that topography and thickness of overburden are the main factors for the intermediate–low stress levels, that regional tectonics governs the stress orientation at the regional scale, and that river erosion, caprock structure and karstic processes have also contributed to the evolution of the valley and in situ stress state.     

叶巴滩水电站坝址区深部变形破裂特征

深入研究叶巴滩水电站坝址区对称发育的深部变形破裂的分布规律、地质特征、类型和控制因素,为进一步评价深部变形破裂岩体质量及可利用性奠定基础。基于野外调查、地震层析成像(CT)、平硐波速测试(Vp)和工程地质类比等方法,揭示深部变形破裂分布规律与宏观地质特征,划分深部变形破裂类型,探讨对称分布的深部变形破裂的控制因素。研究表明:深部变形破裂分布于距边坡表面水平深度约80~140 m范围,具有随高程的升高水平分布深度逐渐增加的规律,两岸均未形成贯通性破裂面;深部变形破裂大多继承早期构造节理形成,具有明显的张性特征,局部受地下水影响,破裂面表层风化加剧;深部变形破裂类型可分为轻微松弛型、中等松弛型和强烈松弛型;地壳抬升、河谷演化和高地应力等区域因素与边坡形态、边坡物质基础及微地貌共同控制深部变形破裂的形成和分布。     

Analyses of stability and support design for a diversion tunnel at the Kapikaya dam site,Turkey

This paper presents the engineering geological properties and support design for a diversion tunnel through diabase at the Kapikaya dam site, eastern Turkey. The rock mass rating and rock mass index were used to determine the support requirements, which were also analyzed using commercial software based on the finite element method. The parameters calculated by the empirical methods were used as input parameters for the FEM analysis and the results from the two methods were compared. It was found that the optimum solution was obtained by using a combination of both empirical and numerical approaches.