Grundwassermonitoring im Zusammenhang mit der hydraulischen Stimulation einer Erdölbohrung

The petroleum well Barth-11 in Mecklenburg-Western Pommerania (2700 m deep) is the first well in eastern Germany to use horizontal directional drilling. Hydraulic stimulation was performed in June 2014, connecting the oil reservoir and borehole. Five Pleistocene aquifers lie within the investigation area, with aquifer depths ranging between 5 and 90 m below surface. Three observation wells were installed for groundwater monitoring. Two weeks before hydraulic stimulation, reference measurements were conducted and a data logger was installed for measurements of water level, temperature and electrical conductivity. To detect any possible influence of hydraulic stimulation on groundwater quality, groundwater samples were analysed for several organic and inorganic parameters.The investigation area is located in a natural saline water discharge zone. Hence, it was necessary to develop methods to distinguish hydraulic stimulation water from Triassic and Permian formation saline water in order to uniquely identify any trace of the injected fluid in the natural groundwater. These methods and the monitoring system design are presented and discussed.     

The Influence of Unlined Boreholes on Groundwater Chemistry: A Comparative Study Using Pore-Water Extraction and Packer Sampling

In the consolidated formations which form most of the major aquifers in the UK, many monitoring boreholes are left unlined (open) for their effective length. They therefore provide pathways for groundwater to flow from one part of the aquifer to another.
A borehole was core-drilled through Triassic sandstones into Permian mudstones at a site in North Yorkshire. Pore water was extracted from the core and compared with conventional depth samples and with samples taken from intervals isolated using packer systems: (a) during drilling, (b) about one month after drilling, and (c) two years after drilling.
The study revealed that natural flow down the borehole led to rapid changes in the quality of water in some parts of the formation.
The implication is that open boreholes can act as conduits to allow flow to take place from one part of the aquifer to another. They are therefore not reliable as sampling points, and may actually accelerate the vertical spread of pollutants. However, this last effect should not be over-stated; in this study, the flow down the borehole was equivalent to the natural flow through only a relatively small area of land.     

Geological challenges in constructing the proposed Geba dam site, northern Ethiopia

It is proposed to construct a dam across the Geba River, Ethiopia. The paper reports the engineering geological investigations undertaken, including mapping, discontinuity surveys, core drilling, water absorption testing and sampling for laboratory tests. The complexity of the site, with limestones and interbedded limestone-shale horizons, is indicated by the variability of the RQD and Lugeon values. Of the 63 tests undertaken, some two-thirds had Lugeon values implying grouting was necessary. Following removal and replacement of the alluvial deposits in the central area, a grout curtain including two to three rows of grouting holes was recommended to a depth of 100 m for the left abutment, 35 m for the central foundation and 60 m for the right abutment.     

贵州风洞含金岩系地质地球化学特征及意义

以贵州省安龙县风洞金矿点为研究对象,对风洞周围地质矿产进行详细调查,出露的地层由上到下依次为下三叠统永宁镇组、下三叠统夜郎组、上二叠统龙潭组,含矿岩系主要赋存于夜郎组,皆出露于断层附近,且可见断层附近岩石矿物较周围蚀变强度明显偏高,表明含矿岩系严格受断层控制。对含矿岩系进行系统采样,测试了包括Au、TFe、As、Sb、Hg、U、Mn共7个指标。结果表明,各组分含量差异较大,以As最为显著,相关性分析结果印证了各组分含量的一致性和差异性。     

Geotechnical study for optimizing the slope design of a deep open-pit mine,India

The study was undertaken to determine the optimal overall slope angle of a lead–zinc mine, which could extend down to a depth of 170 m. Detailed geotechnical investigations were conducted, including geotechnical mapping of existing benches to establish the geometrical and mechanical properties of the discontinuities, the drilling of eight boreholes and the establishment of the physico-mechanical properties of the intact rock. Based on these data, limit equilibrium and numerical simulation techniques were applied to assess the stability of the slopes and determine an optimal slope angle. It was concluded that the overall foot-wall and hanging-wall slopes should be 42 and 48° respectively.      

龙脖河地区构造—地层及成矿作用讨论

龙脖河地区地层系统是一套由印支（ 青藏滇） 板块俯冲碰撞扬子板块造山时形成的混杂的构造复合地质体。其主体地层应为二叠纪的泥砂质－ 火山岩建造,混有元古宙岩块和三叠纪岩块。其成矿作用主要受二叠纪火山岩相及火山机构控制。采用造山带区域地层学———非史密斯地层学方法来恢复其原始状态,有利于查明成矿作用、矿体产出规律,找矿才会有新的突破     

秦岭沉积岩容矿型金矿的控矿条件与找矿方向

秦岭地区沉积岩包括从扬子地台北缘的志留纪裂陷沉积到晚古生代被动大陆边缘断陷—坳陷盆地沉积和三叠纪裂陷沉积。现有勘查资料表明,秦岭地区沉积岩容矿型金矿大多集中在泥盆系和三叠系,少量分布在志留系、石炭系和二叠系。地质地球化学研究表明,该区沉积岩容矿金矿类型有细碎屑岩容矿的变形变质动热改造型、碎屑岩薄层灰岩容矿的韧性剪切带型、钠长角砾岩钠长板岩容矿的热水喷流型、碎屑岩碳酸盐岩容矿的浅成低温热液（ 热泉） 型和含碳泥质岩容矿的推覆构造型５ 种。该区金矿控矿条件为盆地边缘隆起带控矿、热隆起周边剥离断层系统控矿、不同岩性界面的推覆构造及剪切构造控矿和多期活动的深大断裂控矿     

黔西南那郎金矿地质特征及找矿模型研究

那郎金矿位于"南盘江—右江成矿区",为典型的微细粒浸染型金矿。文章通过对那郎金矿的地层、构造和围岩蚀变等综合分析,总结矿床地质特征和成矿控矿因素,确定找矿标志,建立了综合找矿模型,探讨了找矿方向。研究表明,该矿区的赋矿围岩为三叠系下统罗楼组第一段和二叠系上统吴家坪组;矿体及矿化体的控矿构造主要为近南北向、北西向、南东向断裂构造;与金矿化密切相关的围岩蚀变为硅化和黄铁矿化。     

Determination of the damaged zone in quarries, related to aggregate production

To make quarrying profitable, the blasting should effectively disintegrate the rock mass whilst at the same time minimising damage to the individual rock fragments. The zone of damage around blast holes has been considered in two quarries: in Permian dolerite at Billingsryd and tonalitic gneiss at Angered Quarry. The paper describes the fracture mapping and ultrasonic measurements undertaken. Electronic Publication     

Assessment of concrete quality using non-destructive techniques,Ghatghar project,Maharashtra, India

The Ghatghar Pumped Storage Scheme involves the construction of two roller compacted concrete dams. Cracks were observed when the 14.5m × 478 m dam across the river Pravara near Ghatghar village, Maharashtra, India was about 4.1 m high on the right side and 3.3 m high on the left side. A total of 1,206 measurements were made using seismic refraction, sonic tomography and ultrasonic testing to assess the competency of the dam, covering a volume of 5029.86 m³. The ultrasonic testing conducted on five RCC cores and an equal number of rock cores recovered from the body of the dam and site indicated a velocity of 4,050–4,250 and 3,900–4,100 m/s, respectively. The velocities obtained from the seismic refraction and tomographic survey ranged between 3,375 and 4,625 m/s and from the ultrasonic survey 3,800–4,300 m/s. The velocity range obtained from both the seismic (refraction and tomographic) and ultrasonic methods indicates good to excellent quality concrete and the results show the visible cracks have not affected the integrity of the dam.      

Natural and man-made causes for the “Elísio de Moura” earth flow in Coimbra,Portugal

The paper reports the 27 December 2000 landslide, which occurred in the city of Coimbra, central Portugal, affecting loose fill soils and slope debris derived from the red sandstone of Triassic age. With urban spread, the base of the hill slope on which farming had taken place over many centuries was terraced to provide residential properties; the excavated material was end-tipped at the top of the slope, modifying the slope gradient from the original 18° to 38°. The loose fill was placed without engineering precautions, directly on to the debris slope material. Following a small slip in 1998, remedial works were undertaken involving large diameter piles anchored into the bedrock. This engineering construction formed the back slope and restricted the extent of the December 2000 landslide, which occurred during a period of unusually heavy rainfall.     

超镁铁岩的REE特点及其对青海德尔尼铜钴矿的成因意义

不同成因的超镁铁岩具有不同的ＲＥＥ特点。与硫化镍矿有关的侵入超镁铁岩有较高的ＲＥＥ含量，富集轻稀土；蛇绿岩套中的变质橄榄岩ＲＥＥ含量较低，以“Ｕ”型或轻稀土亏损型为特点。德尔尼超镁铁岩体有变质橄榄岩的ＲＥＥ特征，属蛇绿岩套的一部分，为地幔物质低度部分熔融的产物，部分熔融程度约为５％。德尔尼铜矿属火山成因的块状硫化物矿床，由于构造作用致使矿体产于超镁铁岩中。阿尼玛卿山地区铜钴矿的找矿方向是原布青山群和部分三叠系中玄武岩－硅质（碳质）板岩出露地区。     

Modeling of annular fluid pressures in horizontal boring

Horizontal directional drilling (HDD) is minimally-intrusive construction method for installing underground utilities and pipelines. Today, HDD is becoming widely accepted as a cost-effective alternative to traditional open-cut construction. The occurrence of hydraulic fracturing, resulting in the migration of drilling fluid to the surface, has placed the HDD process under scrutiny, especially when considered for projects in environmentally sensitive areas. Hydraulic fracturing results when fluidic pressure within the borehole exceeds the shear strength or undrained cohesion of the strata. Models have been developed to predict borehole pressures; however, there is only limited information available on the properties of drilling returns obtained during HDD installations. A research program was undertaken to determine flow characteristics for drilling returns under a variety of soil conditions and bore penetration rates. Soil samples were gathered based on the Unified Soil Classification System (USCS) and their rheological properties were obtained for different drilling fluids and slurry densities. Presented in this paper is a methodology for predicting borehole fluid pressures over a wide range of project parameters that can be used as a guide to minimize the occurrence of hydraulic fracturing.     

西藏马拉松多铜矿床地质特征及找矿潜力分析

马拉松多铜矿床位于藏东地区,产于著名的西南三江成矿带上。矿区出露地层为三叠系下统马拉松多组(T_1m)酸性火山岩和三叠系上统甲丕拉组(T_3j)碎屑沉积岩。矿区位于背斜核部一侧,断裂构造不发育。矿区总共出现3个黑云母二长花岗斑岩体,为高钾钙碱性系列—钾玄岩系列,同位素年龄(K-Ar法)为34. 6～40. 8 Ma,属喜山早期产物。矿区具面型蚀变特征,由中心至边缘的分带为钾硅化带—绢云母化—角岩化带—青磐岩化带。昂克弄岩体已全岩矿化形成矿体,矿体平面呈椭圆形,长约950 m,宽约800 m;剖面上呈不规则柱状,矿体平均垂直厚度315 m;矿体铜资源量150万t,Cu平均品位0. 36%。根据矿床特征分析,为典型的斑岩型铜矿床。矿体深部和边部有较大的增储潜力和找矿空间。     

Construction risks of Huaying mount tunnel and countermeasures

The Chongqing-Guang’an motorway is planned to cross Huaying mount at Jingguan town of Chongqing city. The whole mount is a colossal anticline whose core is consisted of coal measure strata (upper Permian Longtan formation P₂l) and the limbs are limestone strata (middle Triassic Leikoupo formation T₂l and lower Triassic Jialingjiang formation T₁j). The tunneling is full of risks of collapse, gas explosion or gas outburst, water (mud) inrush, gas inrush because of existence of faults, high pressure gas, karst tectonics and coal goafs around the tunnel. In order to cope with the high risk, two main countermeasures were taken to ensure security of construction. One is geology prediction, and the other is automatic wireless real-time monitoring system, which contains monitoring of video, wind speed, poisonous gas (CH₄, CO, H₂S, SO₂), people location, and automatic power-off equipment while gas contents being more than warning threshold. These ascertained the engineering safety effectively.     

贵州某萤石矿地质特征及矿床成因

贵州贞丰县新近开发的某萤石矿具有较大规模,萤石矿体形态呈现为层状、似层状,局部呈透镜状产出,矿体走向北西,长约3200 m,倾向与背斜轴两翼近似平行,沿倾向延深约200 m,矿体厚度2.00～6.90 m。文章通过对区域地质、矿区地质、矿体地质特征的研究和分析,认为该萤石矿的主要成矿要素为沉积盆地、灰岩、火山喷发活动、褶皱,在各成矿要素的共同作用下,形成了二叠系上统龙潭组第一段(P_3l~1)和二叠系中统茅口组(P_2m)之间的构造蚀变体(Sbt),发育出了多种矿物的矿体,含萤石矿、锑矿、金矿等,是一处沉积改造型萤石矿。这些矿体的共同特点是沿断裂、背斜平行分布,以背斜轴部为中心,两侧延伸,为矿山的找矿工作指明了方向。     

广州番禺某段定向钻LNG管线探测的验证

广东液化天燃气(LNG)输气干线项目一期工程的广州段中,水平定向钻技术在铺设穿越江河、铁路、公路及建筑物等的地下管线施工方面得到大量的应用。水平定向施工的管线往往埋深大于5m,因此,有必要对埋深大于5m的管线探测方法及结果进行验证。本文详细介绍了番禺海傍的LNG定向钻管线的探测方法,也提出了深度模拟计算公式,水冲法钻探验证的方法。本次钻探结果表明:探测埋深小于7m时可以满足精度要求,探测埋深大于7m时,要进行必要的深度修正。     

Geotechnical assessment of the Amalias to Syntagma pilot tunnel, Athens Metro

 From the site investigation data, difficult geotechnical conditions were anticipated for the 9.6-m-diameter tunnel-boring-machine (TBM) drive between the Olympion and Syntagma stations of the Athens Metro. In addition, due to the difficult geological conditions, including zones of highly sheared phyllites and mylonites, it was anticipated that ancient wells and canals would exist at or above tunnel level. To reduce the uncertainties and hence the risk of collapse beneath a busy main road, a decision was made to drive a 208-m-long pilot tunnel, approximately 2.5 m in height and 3 m in width. Extensive face mapping was undertaken as the drive progressed, and, in the light of the information obtained, an RMR* value was produced, from which the temporary lining of the walls was determined. Where appropriate, ground improvement was undertaken. The TBM was successfully driven through the area. Received: 10 September 1999 · Accepted: 29 August 2000     

松原5.7级地震砂土液化研究

2018年5月28日吉林省松原市宁江区发生M5.7级地震,震中地区出现典型罕见的大范围砂土液化现象。通过震害现场调查,结合钻探取样、标贯试验、波速测试及静力触探等试验测试手段,查明震害情况和场地特性,初步分析此次大范围砂土液化的形成条件和影响因素。调查结果表明,此次地震液化区域面积约80km2,宏观现象主要以水稻田内表喷水冒砂为主,未造成建筑物大规模破坏,且区域内土层分布相对单一,液化分布主要受地震动、地形地貌及地下水位等因素控制;液化土层埋深主要在10m以内,并且钻探揭露一处埋深17m左右黏土层中的液化砂土上升通道,证明本次地震中出现明显的深层砂土液化现象,该现象在地震现场调查往往被忽略;静力触探在鉴别液化层位、获取土层物理力学参数上具有一定优势,较适用于震后现场调查工作。另外,松原市具有发生更大规模砂土液化的可能性,在防震减灾规划及建设工程勘察设计等项目中,对该地区的砂土液化情况需进行专门研究。     

敦煌莫高窟保护工程施工振动对洞窟文物的影响

 为保护敦煌莫高窟文物,消除不安全隐患,拟对崖体进行加固,对栈道进行修缮改造,同时对风沙危害进行综合防治。崖体加固中的锚孔钻进振动必然对石窟文物产生影响。为弄清施工振动的传播及其对石窟文物的影响程度,在莫高窟进行洞窟岩体动力学参数测试和锚孔钻进振动试验。试验结果表明：(1) 莫高窟洞窟围岩的纵波速度为1 100～1 930 m/s;(2) 岩体共振频率为75～90 Hz;(3) 波速受洞窟空间分布的影响很大;(4) 距锚孔钻进1,2,3 m处所测的振动峰值速度大多为0.1～1.0 mm/s;(5) 钻头高压冲击最大振动速度达6.01 mm/s。如果选取0.1 mm/s的洞窟文物防护标准来衡量,锚孔钻进振动有可能对洞窟文物产生不良影响。只有采用0.8～0.9 MPa低气压和≤0.4 m/min的慢速钻进,并采用适当的防护措施,才能减缓或消除锚孔钻进施工振动带来的不良影响,避免石窟文物遭受损坏。