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1.
Naturally occurring landslides can be difficult to characterize and often exhibit anomalies in controlling geometry and consistency. The characterization of landslides in engineering geology practice is usually based on program of subsurface exploration; focused on identifying subsurface materials, structure and stratigraphy, hydrologic conditions, and appropriate strength parameters. On native slopes bereft of anthropogenic modification (excavation), geomorphic evidence of previous movement and its relative depth and scale are often discernible to the experienced eye. This paper seeks to describe the various techniques that have been successfully employed in site-specific subsurface investigations of prehistoric landslides. These include considerations of limiting geometry (for planning subsurface exploration and sampling), overcoming problems with site access, exploratory trenches, small diameter borings, downhole logging of large diameter borings, and geophysical techniques. These procedures can be combined to develop more realistic cross sections along the vector of maximum landslide movement, so the displaced mass can be realistically analyzed. The respective advantages and disadvantages of these techniques are discussed, with baseline references on subsurface exploration. 相似文献
2.
因围岩质量评价对地下洞室的设计、施工具有重要作用,因此勘察规范对洞室围岩质量评价具有明确的规定。围岩质量评价方法很多,但在勘察阶段,围岩质量的评价结果与实际情况有很多差别。造成这种问题的主要原因是岩体质量评价需要准确而丰富的工程地质数据,而在勘察阶段,洞室围岩的直接数据有限,多为间接数据(物探数据)和推测数据(以地表工程地质测绘数据和钻孔数据为基础进行推测)。根据勘察阶段所获得的工程地质数据,以钻孔中岩心质量与测井数据之间的关系为基础,建立岩体质量与地球物理参数之间的关系,多种地球物理参数对比,可以比较准确地预测目标围岩质量。通过某花岗岩体中钻孔随深度变化的BQ值曲线、RQD曲线、测井曲线和电磁法物探剖面的对比,发现岩体质量与物探数据很难一一对应,但其大致趋势一致。 相似文献
3.
To dimension a geothermal array, it is necessary to explore the geophysical and geologic qualities of the subsoil. At the following example the project engineering of a prospective geothermal array is shown from the investigation up to the execution planning. For the geothermic investigation a 400 m (1312 ft.) deep drilling was established and equipped with 50 mm (1.97 in.) duplex BHE. With the mounting of the BHE a fiberglass hybrid cable was inserted as a loop parallel to the shanks of the BHE. By means of optical frequency domain reflectometry (OFDR) an enhanced geothermal response test has been executed. Due the high local resolution of the resulting profile of conductivities the geological profile can be differentiated in areas with mainly conductive and areas of convective influenced heat transfer. By knowledge of these both parts and its parameters the incident of groundwater flow on the BHE can be calculated (Peclet number analysis/ Darcy velocity). With the help of the ascertained geophysical and hydraulic rock parameters solid rock, cleavages and karst cavity could be identified. Also the undisturbed ground temperature, the effective thermal conductivity and areas with different geothermal gradients and the groundwater velocity in cleaved and caveated rocks could be determined. 相似文献
4.
Assessing the existence, location, and mapping of geologic anomalies, such as fractures and cavities within soil and rock, are common to both engineering and hydrologic project needs. There are numerous measurement techniques available to detect, map, and characterize fractures and cavities. A summary of the common methods available for fracture and cavity detection and mapping are presented along with their spatial sampling capabilities. The remote sensing and geophysical methods are but a small part of this list but provide a wide range of tools to attack the problem. They include some of the most effective methods for locating and mapping fractures and cavities and cover the complete range of spatial sampling, from regional to no more than the surface of a borehole wall. An understanding of all of the tools available and their spatial sampling limitations is a necessary part of planning and carrying out an effective fracture/cavity investigation. 相似文献
5.
清水营煤矿岩体节理与裂隙发育,富水性较好,属于典型的＂三软＂煤层。工作面推进过程中顶板易碎、易冒;煤层开采中,软岩巷道稳定性控制与支护问题,严重制约了该矿井的安全生产。该矿在掘进巷道过断层时,发生突发性漏顶事故,致使巷道停掘。在分析了研究区岩性、构造、地球物理特征以及煤岩的物理力学参数的基础上,针对现场地质条件变化先后采取了两套施工方案对漏顶区进行加固。最终依靠方案二获得了成功,即采用对掘进迎头冒顶区采用水泥、水玻璃浆液加固冒顶区,并对冒空区采用马丽散泡沫充填。施工完成后从迎头退后36m起底,由冒顶区下部通过。现场实践证明,方案二具备安全性与经济性,可为＂三软＂条件下的巷道开采系统设计、岩层控制、安全回采提供地质保障与技术支持。 相似文献
6.
A. K. Naithani P. C. Nawani L. G. Singh Devendra Singh 《Journal of the Geological Society of India》2013,81(6):835-843
The 200m long and 106.2m wide spillway of Bunakha Hydroelectric Project is proposed at the centre of the dam to pass the flood discharge. The spillway area was investigated through detailed engineering geological mapping, geophysical survey, exploratory drilling and laboratory testing. The rock mass properties, i.e. joint sets, weathering grade, RQD, RMR, permeability, P-wave velocity etc. of the rock masses to be encountered during the excavation of spillway have been analyzed in detail. Core samples from the exploratory drill hole drilled at the spillway alignment were tested for physico-mechanical properties of rocks in the laboratory. The mapping details indicated that the major rock types which are exposed to the surface and cover the entire spillway area are foliated gneisses with bands of banded gneisses. On the basis of detailed investigations and laboratory testing, inferences and recommendations have been made which will be helpful during the construction of the project. 相似文献
7.
简述了洪积扇地形地貌、土层结构、水文地质、特殊性岩土等各种工程地质条件，划分了勘察阶段，明确了各阶段勘察目的和任务，并重点介绍了在详细勘察阶段优质、高效完成野外勘察和测试工作的成功经验，明确指出了洪积扇场地非常适合钻孔、探井、测井等勘察手段和动力触探等原位测试方法。 相似文献
8.
Measuring rock mechanical parameters is an essential step for support design in an underground project. To quickly obtain the surrounding rock mechanical parameters at a construction site in real time using a digital drilling rig, a quantitative relationship between the drilling parameters and rock mechanical parameters should be defined. In this paper, based on the fracture characteristics of rock cutting, a relationship model for the drilling parameters of the digital drilling rig versus the rock mechanical parameters (DP-RMP model) is created. Based on the multi-function rock drilling test system developed by the authors, rock drilling tests for different drilling parameters and theoretical results are compared and analysed to prove the validity and accuracy of the DP-RMP model. Additionally, the influence laws of the cohesion and internal friction angle on the rock cutting drilling torque are investigated. Drilling parameters from the digital drilling rig-based rock mechanical parameter inversion method is proposed; the feasibility of this method is verified by rock drilling test results. The study provides a theoretical basis for quickly obtaining the rock mechanical parameters using drilling parameters on site in real time. 相似文献
9.
地质雷达勘探技术以其独有高分辨率、高效率、无损检测的特点可满足超前地质预报施工要求，在隧道施工，能够准确预报掌子面前方岩体构造情况和不良地质体，对隧道混凝土衬砌常见的问题如：衬砌和围岩的结合部的缺陷、局部裂缝、衬砌厚度不足、土衬砌与围岩出现的脱空、回填欠实、富水区等进行有效的检测。 相似文献
10.
Leila Djadia Djamel Machane Jean-Luc Chatelain Abdesslam Abtout Rabah Bensalem Mehdi Amine Guemache Bertrand Guillier Amar Boudella El-Hadi Oubaiche 《Environmental Earth Sciences》2010,59(5):1149-1158
Results from geophysical investigations (electrical resistivity, electromagnetic mapping and seismic refraction) on an excavated
cell of the Ouled Fayet (Algiers, Algeria) pilot landfill indicated the presence of an underground runoff and permeable soil
underneath the cell. These results contradict those obtained by a feasibility study, based, however, only on the analysis
of seventy-six 10-m drilling cores. The 1D boreholes information has been proven to be insufficient and to give biased results.
The presence of water at depth is evidenced by lower resistivity, high conductivity anomalies and increase of P-wave velocity.
Thus, to the contrary of what is claimed in the feasibility study, a threat of leachate pollution is real. This study shows
that landfill construction studies cannot give trustful results without geophysical investigations. More specifically, in
Algeria, it is imperative to elaborate a landfill construction code, which should include mandatory geophysical prospecting
and deeper drilling cores. 相似文献
11.
采用综合物探等方法对南京赭山头水库长期存在的渗漏问题进行探测,在物探探测渗漏区结合地质钻探确定大坝的渗漏通道,对存在渗漏通道的左右坝肩部位,采用薄壁混凝土防渗墙和帷幕灌浆的方法进行防渗处理,经过汛期高水位的检验,水库多年存在的渗漏险情得到了根本解决。 相似文献
12.
为了给项目的设计和施工提供科学依据，对武汉绕城公路东北段软土、膨胀土、砂土地震液化、岩溶、深路堑、高填路基、筑路材料等潜在的地质灾害进行了详细评价，通过采用工程地质测绘及钻探、触探、物探、试验分析等多种勘探、测试手段，对沿线的各种工程地及其危害表现形式进行计算分析，预测施工过程及工程建成后可能出现的岩土工程问题，提出了相应的施工方法，对同类工程的建设具有指导意义。 相似文献
13.
顺层岩质斜坡是沉积岩地区常见的一种斜坡类型,也是各种工程建设重点关注的一类斜坡。以川西雅安地区典型的顺层岩质斜坡为例,采用现场调查、无人机测绘、钻探、物探和稳定性计算等技术方法,归纳总结目前斜坡存在的变形破坏模式。分析计算斜坡在不同工况条件下,层间破碎带连通率与斜坡稳定性之间的关系。研究结果表明:层间破碎带对斜坡稳定性具有重要的影响或控制作用,当斜坡浅表部强风化岩体内层间破碎带连通率小于86%时,斜坡稳定性与现状调查结果吻合。研究结果对川西地区基础设施规划建设和防灾减灾具有重要的工程意义。 相似文献
14.
为评估建新煤矿建设工程区地质灾害危险性,评价工业场地建设和煤矿开采的适宜性,依据钻孔和矿产资源开发利用方案等相关资料,在野外现场调查的基础上,通过定性与定量相结合方法,对研究区的地质灾害进行了评估。结果认为：评估区内有危险性大区8个,面积0.100 050km2,危险性中等区1个,面积14.965 013km2,危险性小区5个,面积3.459 323km2;工业场地建设为基本适宜,煤矿井下开采在地质灾害危险性大区和中等区,按有关规范、规程要求,采取合理的开发方案和有效的避让或防治措施后为基本适宜,在危险性小区适宜煤矿开采。 相似文献
15.
煤矿采空区勘察是制约上方场地能否进行工程建设及长期安全运营的重大技术难题.以我国煤矿采空区勘察技术规范制定为时间脉络,回顾了近30年来在采空区勘察方法、变形预测、稳定性评价等方面所取得的成果,指出了目前勘察实际工作中遇到勘察大纲编制指导性不强、钻探技术要求与勘察工作结合不紧密、工程物探难以满足勘察需求、勘察成果综合分析... 相似文献
16.
深层重力流水道砂体储层预测方法及效果分析 总被引：2，自引：0，他引：2
由寻找单纯构造圈闭发展到岩性圈闭，及识别隐蔽非背斜岩性圈闭，如何准确对该圈闭进行定量化储层预测描述，以及储层预测的精度、可靠性合理评价，一直是地质研究人员关注的问题。依靠高品质地震、地质、测井、钻井、分析化验等资料，结合地球物理新技术、新方法，围绕深层重力流水道砂体如何从定性分析到定量预测这一核心问题，各种技术方法相互配合，成功地进行了多方法的砂体厚度预测、渗透砂体预测、物性参数预测。经钻井资料验证，均见到较好地质效果，为深层重力流水道砂体发育区的储层定量化预测摸索了一套行之有效的方法。 相似文献
17.
TSP在公路隧道超前地质预报中的应用研究 总被引：14，自引：0，他引：14
根据TSP技术的特点,将TSP技术应用于掌子面前方不良地质对象的预报工作中,同时比较了基于地质雷达和基于TSP的预报结果。水平地质钻探与现场开挖的实际情况表明,基于TSP技术的隧道超前预报,在预报距离,预报的准确性,以及对围岩的判别等方面,均明显优于传统的地质雷达。文章最后还指出了该技术存在的一些待进一步研究的问题。 相似文献
18.
M.K Seguin 《Geoforum》1974,5(2):55-67
A brief summary of our knowledge of permafrost is presented. The general properties and the thermal regime of permafrost encountered in the Schefferville area are discussed. The factors influencing the occurrence or disappearance of permafrost are discussed individually. Attempts to determine the mechanical and thermal properties of frozen rock materials, with the aim of relating these to geophysical results and to the various blasting responses appear to represent the best approach. In addition to the mapping of topography, drainage patterns, distribution and type of vegetation, snow cover and installation of thermistors, electrical resistivity surveys, borehole geophysical techniques and seismic refraction method are now recognized as important tools in predicting and outlining permafrost zones where blasting and handling procedures of iron ore are very expensive and difficult. Examples and results of such studies carried out on the Timmins 1, Timmins 4, and Fleming 3 deposits are presented. As the mining operations will move northwards into the Timmins, Barney, Goodwood, Leroy and Kivivic groups of deposits, an increasing percentage of the mining activities will be located in permafrost; consequently, it is of the utmost importance to develop a technique permitting a rapid and accurate prediction of permafrost zones in order to reduce prohibitive costs of operation. The delineation of permafrost in a particular deposit has many practical applications such as the demarcation of areas where trenching and test pitting is planned, prediction of ground conditions for test and tonnage drilling, delineation of areas of open cast walls which will be affected by permafrost and consecutive importance in slope design, operational planning of areas where free digging is possible during dirt (overburden) stripping and economic planning of mining operations, particularly with respect to drilling and blasting costs. Additional important applications include the delineation of areas of potential water problems during operations due to the presence of permafrost in the wall rocks and broad outline of the blasting patterns and choice of charge distributions to be used. 相似文献
19.
Sinkhole collapse is one of the main limitations on the development of karst areas, especially where bedrock is covered by
unconsolidated material. Studies of sinkhole formation have shown that sinkholes are likely to develop in cutter (enlarged
joint) zones as a result of subterranean erosion by flowing groundwater. Because of the irregular distribution of pinnacles
and cutters on the bedrock surface, uncertainties arise when "hit-or-miss" borehole drilling is used to locate potential collapse
sites. A high-resolution geophysical technique capable of depicting the details of the bedrock surface is essential for guiding
the drilling program. Dipole-dipole electrical resistivity tomography (ERT) was used to map the bedrock surface at a site
in southern Indiana where limestone is covered by about 9 m of clayey soils. Forty-nine transects were conducted over an area
of approximately 42,037 m2. The electrode spacing was 3 m. The length of the transects varied from 81 to 249 m. The tomographs were interpreted with
the aid of soil borings. The repeatability of ERT was evaluated by comparing the rock surface elevations interpreted from
pairs of transects where they crossed each other. The average difference was 2.4 m, with a maximum of 10 m. The discrepancy
between interpreted bedrock-surface elevations for a transect intersection may be caused by variations in the subsurface geology
normal to the transect. Averaging the elevation data interpreted from different transects improved the ERT results. A bedrock
surface map was generated using only the averaged elevation data at the transect junctions. The accuracy of the map was further
evaluated using data from four exploratory boreholes. The average difference between interpreted and actual bedrock surface-elevations
was less than 0.4 m. The map shows two large troughs in the limestone surface: one coinciding with an existing sinkhole basin,
while the other is in alignment with a small topographic valley. Because sinkholes were observed at the same elevation interval
in similar valleys in the vicinity, the delineated trough may have implications for future land use at the site.
Received: 4 January 1999 · Accepted: 8 March 1999 相似文献
20.
For construction in rock a thorough pre-investigation is important in order to avoid unforeseen conditions which may delay the work. It is crucial to remember the results from this investigation in the further work, and use the experience from the construction to update the geological prognosis and reduce the uncertainties. Different geophysical methods have proved valuable tools in such investigations. In this work the electrical imaging is evaluated with regards to the method's applicability. The evaluation is done qualitatively by comparing the electrical imaging with tunnel documentation from a tunnel in Southern Sweden. By evaluating the result continuously when making the tunnel a more detailed geological prognosis can be compiled and used in the continued work with the tunnel. The parameters used for the comparison are lithology, Q, RQD, weathering and water leakage. The result was that virtually every change in electrical resistivity image coincides with a change in rock conditions. The general trend was that high resistivity corresponded with good quality gneiss whereas low resistivity corresponds to poor quality rock e.g., high weathering, low RQD, low Q and/or several lithological contacts. The intermediate resistivity is often amphibolites or rock with water bearing fractures. The results were supported by in-situ resistivity measurements inside the tunnel and resistivity logging in a core drilling. Geoelectrical imaging proved to give valuable information for a detailed geological model, which could be compiled for a section where the tunnel had not yet been drilled as a help for planning of the continued tunnel work. As is the case other geophysical methods it is clear that for the interpretation of data a priori information about the geological setting is necessary. 相似文献