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1.
Hydraulic conductivity and pore fluid chemistry in artificially weathered plastic clay 总被引：1，自引：0，他引：1
Triaxial and oedometer tests have examined how freezing–thawing (FT) and drying–wetting (DW) affect the hydraulic conductivity of a natural plastic clay. Because the clay was expansive, FT and DW in the laboratory produced only one order of magnitude increase in hydraulic conductivity above the ‘undisturbed’ value when permeated with water. Permeation with sodium carbonate or dimethyl sulfoxide reduced the hydraulic conductivity towards the undisturbed value, though some increases still remained. Hydraulic conductivities measured by oedometer were lower than those in the triaxial tests and varied strongly with applied pressure. 相似文献
2.
Yohannes Yihdego 《Geotechnical and Geological Engineering》2017,35(1):29-44
Hydraulic in situ measurement of rock mass permeability by packer (Lugeon) testing is an inherent and integral element of many engineering, hydrogeological and mining investigation. This paper describes and discusses geotechnical testing in the design process from a consulting practitioner’s perspective. This study focuses on the Packer testing planning, procedure, results & interpretation. Packer test system is an optimum method for obtaining values of hydraulic conductivity in wells that are difficult to analyse using conventional slug test systems. Packer tests are carried out to assess the variability of a borehole as it intersects various hydrogeological units. It gives vertical distribution of hydraulic properties and water quality in the aquifer and usually cheaper than a nest of wells and gives more continuous record and this knowledge can often be essential for a proper design. The role, objectives, types and interpretation of testing, limitations and recommended good practices as part of the geotechnical design process are outlined through the examination of test data from a case record. 相似文献
3.
Cement–bentonite walls are commonly used for remediation by containment or pollution prevention, in addition to their use as a barrier to water flow in more conventional construction. The results from an investigation of an in situ single-phase cement–bentonite slurry wall are detailed, with particular attention paid to the role of advective and diffusive fluxes in contaminant transport.
The wall under investigation was installed, using standard methods and with a normal mix design, in August 1995 in order to contain leachates arising from ‘piggy-backing’ of an existing ‘dilute and disperse’ landfill site. In September 1998, the wall was investigated during which the top of the wall was exposed at adjacent locations allowing the drilling of three boreholes using rotary coring techniques. Core recovery and quality were high and samples obtained during coring were retained for testing in the laboratory.
The material recovered was quite strong and not treatable by conventional soil testing and preparation techniques. In addition, the material was susceptible to drying upon exposure to the atmosphere, with an accompanying loss of structure. In spite of this, meaningful laboratory tests were undertaken. Hydraulic conductivity of the samples was measured using constant flow-rate methods and the relative importance of the diffusive flux was investigated using a variety of simple techniques. The advective flux was found to be the dominant contaminant transport process. The results of the laboratory test programme are presented and placed in the context of the long-term performance of cement–bentonite slurry walls. 相似文献
4.
Ali El-Naqa 《Environmental Geology》2001,40(8):973-982
This paper outlines the hydraulic characteristics of fractured rock masses and their implication in engineering works. The hydraulic behavior of subsurface fracture systems has been evaluated by means of hydraulic testing using packer tests and by fracture analysis. A comparison of the borehole results with those of surface fracture mapping provides a reasonable correlation between the two methods of measuring fractured rock hydraulic conductivity. The mean hydraulic conductivity value obtained from the boreholes is 36.5 LU (9.26᎒-5 m/s), while the mean value of hydraulic conductivity obtained from field mapping of fracture data is in the order of 1᎒-5 m/s. Based on the hydraulic conductivity values the sandstone rock mass can be considered medium to highly conductive; nevertheless, it seems to be almost impervious at greater depth. The empirical relationships which have been derived between hydraulic conductivity and both rock quality designation (RQD) and rock mass rating (RMR) indices indicated that the mean value of hydraulic conductivity of the rock mass could be estimated to be in the order of 10-5 m/s, which is confirmed by the packer tests. 相似文献
5.
Sung-Soo Cha Jin-Yong Lee Dae-Hyuck Lee Eric Amantini Kang-Kun Lee 《Engineering Geology》2006,84(3-4):229-243
Feasibility of storing LNG in a lined rock cavern was evaluated using a pilot cryogenic rock cavern constructed in Daejeon, Korea. The pilot program included hydrogeological and engineering characterization of the rock mass around the cavern, design and construction of a drainage system, and pilot operation of the cryogenic cavern. An appropriate drainage system is most important to protect the containment system of LNG from thermal shocks due to ice lenses and hydrostatic pressure of groundwater. As a part of the pilot program, this study focused on the evaluation of hydraulic and engineering properties of the rock mass around the cavern. For this purpose, engineering logging of the rock cores, single and cross-hole hydraulic tests, and recharge/drainage tests were performed using seven drilled holes with different trends and plunges. Three main joint sets were found from the logging of the rock cores, acoustic borehole televiewer, and window mapping. The orientations of the three major joint sets were 60/209, 40/171, and 29/331, which can provide the main groundwater flow paths. Mean RQD values ranged from 56 to 88, which were classified as fair and good, although varying with depth along single boreholes. Hydraulic conductivity from the single and cross-hole hydraulic tests estimated in the order of 10−6 or 10−7 m/s and corresponding transmissivity ranged between 10−5 and 10−6 m2/s. Permeable intervals identified from the hydraulic tests were mostly located above the cavern roof. Below the roof, the permeable zone was difficult to observe. According to the hydraulic communication tests performed for some designated intervals, hydraulic connection between boreholes was highly varied with depth or location, which indicated a very different distribution of water conducting joint sets along the boreholes. When water was injected at R1 with constant or varying flow rates, monotonous and stable seepage was observed at observation boreholes. From this, some stable drainage was expected even in relatively heavy rainfalls. When designing the drainage system of the cavern, the drainage holes should be orientated to maximize frequency of encountering the major joint sets and the permeable intervals identified from this study. 相似文献
6.
This paper presents the establishment of an empirical HC model for estimating rock mass hydraulic conductivity of highly disturbed clastic sedimentary rocks in Taiwan using high-resolution borehole acoustic televiewer and double packer hydraulic tests. Four geological parameters including rock quality designation (RQD), depth index (DI), gouge content designation (GCD), and lithology permeability index (LPI) were adopted for establishing the empirical HC model. To verify rationality of the proposed HC model, 22 in-situ hydraulic tests were carried out to measure the hydraulic conductivity of the highly disturbed clastic sedimentary rocks in three boreholes at two different locations in Taiwan. Besides, the model verification using another borehole data with four additional in-situ hydraulic tests from similar clastic sedimentary rocks was also conducted to further verify the feasibility of the proposed empirical HC model. The field results indicated that the rock mass in the study area has a conductivity between the order of 10− 10 m/s and 10− 6 m/s at the depth between 34 m and 275 m below ground surface. Results demonstrate that the empirical HC model may provide a useful tool to predict hydraulic conductivity of the highly disturbed clastic sedimentary rocks in Taiwan based on measured HC-values. 相似文献
7.
Measurement of Longwall Mining Induced Strata Permeability 总被引：1，自引：0，他引：1
The paper summarizes the findings of the underground permeability measurements (using inflatable packers) undertaken at a mine site in New South Wales in Australia and highlights the difficulties encountered during packer testing. The research project was supported by the Australian Coal Association Research Project. Within this project, systematic sub-surface and underground hydrogeological monitoring and measurements were carried out e.g. underground packer tests and piezometer, extensometer, and water inflow monitoring during mining. The project was aimed at investigating the effects of longwall mining on strata pore pressure, permeability, and water inflow to facilitate prediction of mining induced aquifer interference and mine water inflow. This paper presents only the results of underground permeability tests conducted at the mine site. The tests show that the drivage of main headings (roadways) can induce a significant change in permeability into the solid coal barrier. Permeability can be seen to increase by as much as 50 times at a distance of 11.2–11.5 m from the roadway rib. The measured permeability values varied widely and strangely on a number of occasions; for example the test conducted from the main headings at 8.2–8.5 m test section in the solid coal barrier showed a decline in permeability value compared to that at 11.2–11.5 m section contrary to the expectations. The tests conducted in the roof strata near (above) the longwall goaf indicated a possibility of more than 1,000 fold increase in permeability. Though the underground packer testing appears to be a good technique for measuring in situ permeability of rocks and coal seams, the study highlighted that (1) boreholes for packer testing need to be drilled with extreme care so as to avoid any undue damage or smearing of the borehole wall and (2) a sufficient number of tests at a number of locations needs to be conducted to cater for the possible variations of the test results. 相似文献
8.
Incipient removal of Cu even from the caprocks, in situ transformation of sulphides to oxidized compounds, fixation of substantial Cu by supergene ‘clay’ minerals, virtual absence of secondary sulphide enrichment, and non-congruence between present water table and the ‘bottom’ of oxidized zone are the unusual features observed in the oxidized profile at Chapri mining-block within the Singhbhum copper belt.
Petromineralogical studies of ore and host-rock samples from drill cores, and in situ measurement of Eh-pH values of mine and surface water furnish an explanation for the observed features. Occurrence of low-pyrite orebodies as sheeted veins and disseminations accounts for localized, inadequate generation of strong acids that was readily consumed by hydrolysis reactions in host rock. This inhibited any significant migration of Cu, outwards or downwards, by: (a) precipitating oxidized compounds; and (b) fixation of Cu in supergene, neoformed clay minerals. Vertical zoning of copper minerals in the oxidized profile is consistent with stability diagrams and with measured Eh-pH values. The ‘bottom’ of the oxidized zone presumably represents a palaeo-water table, tilted in sub-recent time.
Preliminary leaching experiments indicate feasibility of exploitation of Cu left out in the oxidized zone. 相似文献
9.
温度和有效应力对砂岩渗透性影响的试验研究 总被引：1，自引：0，他引：1
为探讨温度和有效应力对渗透性的影响,在不同温度水平和不同有效应力水平下进行了砂岩的渗透率试验。根据试验结果,初步分析了温度和有效应力对砂岩渗透率及其水力传导系数的影响。试验结果表明,砂岩的渗透率及其水力传导系数都是温度和有效应力的函数:在温度一定的条件下,砂岩的渗透率和水力传导系数均随有效应力的增加而呈负指数规律减小;在有效应力一定的条件下,砂岩的渗透率随温度的升高而减小,但水力传导系数与温度之间的关系函数并非单调函数。因此,在工程实践中不考虑温度和有效应力对岩石 (体)渗透性的影响是不合适的。 相似文献
10.
Stress-induced breakouts in vertical boreholes are failure zones caused by excessive compressive stress concentration at the borehole wall along the springline of the least horizontal far-field stress. Wellbores are sometimes drilled into aquifers or oil reservoirs that are weak, poorly consolidated, and highly porous sandstone formations, which are often conducive to breakout formation. Breakouts are an expression of borehole instability and a potential source of sand production. On the other hand, the breakout phenomenon can be used advantageously in obtaining an estimate of the in situ stress condition. The average orientation of breakouts, as identified by borehole geophysical logging, is a reliable indicator of in situ stress directions. It has also been suggested that breakout dimensions could potentially be used as indicators of in situ stress magnitudes. The research reported here has concentrated on the unique type of breakouts observed for the first time in high-porosity Berea sandstone. Drilling experiments in rock blocks subjected to critical far-field true triaxial stress regimes, simulating in situ conditions, induced breakouts that were unlike the ‘dog-ear’ ones previously observed in granites, limestones, and low-porosity sandstones. The newly observed breakouts were thin, tabular, and very long, resembling fractures that counterintuitively extended perpendicular to the maximum principal stress. We found that a narrow zone ahead of a fracture-like breakout tip underwent apparent localized grain debonding and compaction. In the field, such zones have been termed ‘compaction bands’, and are a source of concern because in oil fields and aquifers they constitute curtains of low permeability that can impede the normal flow of oil or water. In order to determine whether a correlation exists between fracture-like breakouts and in situ stress, we conducted several series of tests in which the minimum horizontal and vertical stresses were held constant and the maximum horizontal stress (σH) was increased from test to test. These tests showed strong dependence of the breakout length on far-field stress, signaling that potentially the ability to assess fracture-like breakout length in the field could be used to estimate in situ stress magnitudes in conjunction with other indicators. Another series of tests revealed that breakout length increased substantially when borehole diameter was enlarged. This result suggested that in the field, where wellbore size is considerably larger, fracture-like breakout could extend to sizable distances, creating a sand production hazard. Two series of tests, one to evaluate the effect of drill-bit penetration rate, and the other to verify the drilling-fluid flow rate effect on breakout formation and dimensions yielded inconsistent results and showed no unique trends. Remarkably, fracture-like breakouts maintained a consistent narrow width of about 5–10 grain diameters, irrespective of the test conditions. This characteristic supports the suggestion that fracture-like breakouts are emptied compaction bands. 相似文献
11.
In recent years, the study of low-permeability geological formations has undergone considerable development. This is mainly due to the use of natural geological barriers to confine waste disposals, preventing leaking water from bringing contaminants into contact with the biosphere and the groundwater resources.In that context, the Spanish Geological Survey (IGME, Spanish acronym), supported by the National Radioactive Waste Management Agency (ENRESA, Spanish acronym) and with the technical advice of the Swedish Nuclear Fuel and Waste Management Company (SKB) designed and built a Mobile Hydrogeological Unit (UMH, Spanish acronym) for low-permeability formations characterization, which has been operational since 1997 and has been used for different purposes. Among other possibilities, the UMH allows conducting: constant transient-state flow-rate injection tests, constant-head transient-state injection tests, pseudo-stationary state injection tests, pressure fall-off tests, slug tests and pulse tests.The main objectives of this article are to describe the hydraulic characterization methodology used by IGME to carry out hydraulic tests in low permeability environment, to compare different testing methods and to summarize the results that have been obtained when characterizing the leucogranites of Cadalso de los Vidrios in Spain.The study area presents an increasing interest for granite production inside the Community of Madrid. The petrological and structural characteristics of the granite rocks and the core-samples extracted from a 200 m deep borehole investigation are described. The packer tests are conducted with the Mobile Hydrogeological Unit.The tests are interpreted with the help of analytical solutions. The main software used is Hytool, an open source matlab toolbox that provides a library of analytical solutions and a set of routines to facilitate hydraulic tests interpretation.The results allow the elaboration of a comparative analysis of the applied hydraulic tests and to define the hydraulic conductivity optimum application interval most suited for each of the used methods.Hydraulic conductivity values obtained varies from 3.20·10− 7 m/s, for the upper weathered layer, to 2.80·10− 12 m/s, for the test section from 97.36 to 116.15 m depth.Finally, the hydraulic conductivity values obtained in this area are compared with other case studies of granite formations around the world. 相似文献
12.
A. Arulrajah M. W. Bo H. Nikraz A. S. Balasubramaniam 《Geotechnical and Geological Engineering》2007,25(6):647-656
In situ dissipation tests provide a means of evaluating the in situ coefficient of consolidation due to horizontal flow and
hydraulic conductivity in horizontal direction in marine clays formation. Dissipation tests by means of piezocone were utilised
in the characterisation of the coefficient of consolidation due to horizontal flow and the hydraulic conductivity in horizontal
direction of Singapore marine clay at Changi. Piezocone dissipation tests were carried out prior to reclamation as well as
after ground improvement with vertical drains to compare the changes in the coefficient of consolidation due to horizontal
flow and hydraulic conductivity in horizontal direction prior to and after ground improvement. The quasi-static piezometric
pressures from the dissipation tests were compared with piezometric pressures from piezometers to determine their possibility
of future use as an alternative to piezometers. Post-improvement CPTU dissipation tests were carried out in the treated “Vertical
Drain Area” as well as in an adjacent untreated “Control Area” for comparison purposes. This study provides support for the
use of piezocone dissipation testing methods for the determination of the coefficient of consolidation due to horizontal flow
and hydraulic conductivity in horizontal direction of marine clays in the region as well as an alternative to piezometer instrumentation
for monitoring of piezometric pressure during consolidation. 相似文献
13.
Determination of the anisotropy of an upper streambed layer in east-central Nebraska, USA 总被引：1，自引：0，他引：1
Chengpeng Lu Xunhong Chen Gengxin Ou Cheng Cheng Longcang Shu Donghui Cheng Emmanuel Kwame Appiah-Adjei 《Hydrogeology Journal》2012,20(1):93-101
Information on the anisotropy of streambed hydraulic conductivity (K) is a necessity for analyses of water exchange and solute transport in the hyporheic zone. An approach is proposed for the determination of K, developed from existing in-situ permeameter test methods. The approach is based on determination of vertical and horizontal hydraulic conductivity of streambed sediments on-site and eliminates the effects of vertical flow in the hyporheic zone and stream-stage fluctuation, which normally influence in situ permeameter tests. The approach was applied to seven study sites on four tributaries of the Platte River in east-central Nebraska, USA. On-site permeameter tests conducted on about 172 streambed cores for the determination of vertical hydraulic conductivity (K v) and horizontal hydraulic conductivity (K h) at the study sites indicate that the study sites have relatively small anisotropic ratios, ranging from 0.74 to 2.40. The ratios of K h to K v from individual locations within a study site show greater variation than the anisotropic ratios from the mean or median K at each of the study sites. 相似文献
14.
为评价滨海地区海（咸）水入侵区不同类型地层渗透性,提出振荡试验适宜模型选择方法。利用Geoprobe系统对不同平面位置地层实施了气压式振荡试验,部分点位进行了分层测试;利用配线法计算地层渗透系数。结果表明:当试验目标层为承压含水层时,利用Butler模型分析欠阻尼振荡试验,KGS模型分析过阻尼振荡试验,均可获得良好的计算结果;当试验目标层为弱透水层时,KGS模型可用于过阻尼振荡试验的数据分析,但计算结果会受到相邻高渗透性含水层以及钻孔编录不准确的影响。地层渗透性等级未知条件下,需根据地层类型、介质岩性、测试井结构和水位恢复过程曲线特征选择适宜的振荡试验分析模型,以准确获取地层渗透系数值。 相似文献
15.
Sellafield in West Cumbria was a potential site for the location of the UK's first underground repository for radioactive, intermediate level waste (ILW). The repository was to lie around 650 m beneath the ground surface within rocks of the Borrowdale volcanic group (BVG), a thick suite of SW dipping, fractured, folded and metamorphosed Ordovician meta-andesites and ignimbrites. These are overlain by an onlapping sequence of Carboniferous and Permo-Triassic sediments. In situ borehole measurements showed that upward trending fluid pressure gradients exist in the area of the potential repository site, and that there are three distinct fluid types in the subsurface; fresh, saline and brine (at depth, to the west of the site). Simulations of fluid flow in the Sellafield region were undertaken with a 2D, steady-state, coupled fluid and heat flow simulation code (OILGEN). In both simplified and geologically complex models, topographically driven flow dominated the regional hydrogeology. Fluids trended persistently upwards through the potential repository site. The dense brine to the west of the site promoted upward deflection of topographically driven groundwaters. The inclusion in hydrogeological models of faults and variably saline sub-surface fluids was essential to the accurate reproduction of regional hydraulic head variations. Sensitivity analyses of geological variables showed that the rate of groundwater flow through the potential repository site was dependent upon the hydraulic conductivity of the BVG, and was unaffected by the hydraulic conductivity of other hydrostratigraphic units. Calibration of the model was achieved by matching simulated subsurface pressures to those measured in situ. Simulations performed with BVG hydraulic conductivity 100 times the base case median value provided the “best-fit” comparison between the calculated equivalent freshwater head and that measured in situ, regardless of the hydraulic conductivity of other hydrostratigraphic units. Transient mass transport simulations utilising the hydraulic conductivities of this “best fit” simulation showed that fluids passing through the potential repository site could reach the surface in 15 000 years. Simple safety case implications drawn from the results of the study showed that the measured BVG hydraulic conductivity must be less than 0.03 m year−1 to be simply declared safe. Recent BVG hydraulic conductivity measurements showed that the maximum BVG hydraulic conductivity is around 1000 times this safety limit. 相似文献
16.
Solvus curves under both ‘dry’ and ‘hydrothermal’ (PH2O = 1 kbar) conditions have been determined for two microperthitic alkali feldspar starting materials from the Loch Ailsh syenite complex, Assynt, Scotland. One sample (Ab74 Or24 An2) possessed a K-phase showing dominant monoclinic symmetry to both powder and single-crystal X-ray methods, the other (Ab88Or30An2) had maximum microcline as K-phase. These materials gave essentially identical solvi for both types of experiment, interpreted as indicating similar degrees of local order in the K-phase, but with differing domain size, leading to the different X-ray properties. The ‘dry’ solvus curves confirm the determination of the microcline-low albite solvus of Bachinski & Müller. The hydrothermal curves are used to estimate PH1O <3.5 kbars, T > 755 °C for emplacement of the Loch Ailsh syenites. 相似文献
17.
裂隙岩体渗透系数确定方法研究 总被引：3，自引：0，他引：3
裂隙岩体渗透系数以及渗透主方向的确定对研究岩体渗透性大小及各向异性具有重要意义。高放废物地质处置库介质岩体的渗透性能将直接影响其使用安全性。本文运用离散裂隙网络模拟的方法对我国高放废物处置库甘肃北山预选区3#钻孔附近裂隙岩体进行了渗透性质分析。通过对3#钻孔171.5~178.0m段压水试验数据的反演,标定了离散裂隙网络渗流模型中的裂隙渗透参数(导水系数T)。利用标定的离散裂隙网络模型对场区裂隙岩体进行了渗流模拟,确定了该区域裂隙岩体的渗流表征单元体(REV)的尺寸大小以及渗透主值和主渗透方向。运用离散裂隙网络模型计算得出的渗透主值的几何均值与现场压水试验计算结果较接近,证明了计算结果的有效性。 相似文献
18.
韩城矿区碎软煤层发育,煤层透气性差,本煤层钻孔钻进困难,瓦斯抽采效果差。顶板梳状孔水力压裂技术结合了水力压裂技术和定向钻进技术二者的优势,是解决碎软低渗煤层瓦斯抽采难题的有效技术途径。在韩城矿区王峰煤矿3号煤层顶板粉砂岩中施工长钻孔并向煤层开分支,采用套管+封隔器座封的整体压裂方式进行水力压裂工程试验。钻孔总长度344 m,有效压裂长度284 m,累计注水量874.79 m3,最大泵注压力9.4 MPa。试验结束后对钻孔瓦斯抽采相关参数连续监测86 d,钻孔瓦斯抽采体积分数27%~51%,平均42.11%,钻孔瓦斯抽采纯量8.25~21.41 m3/min,平均17.02 m3/min,钻孔累计抽采瓦斯量约210万m3。与常规的穿层钻孔水力冲孔技术相比,该技术百米钻孔瓦斯抽采量提高了11.48倍,初步证明了该技术在碎软煤层瓦斯强化抽采领域的适用性。 相似文献
19.
In this research, the hydraulic conductivity changes in uniformly graded sands, due to injection pressure increase, were experimentally evaluated using a cell-type radial model. Conducted tests, simulating variation of media permeability at different depths along a recharge well, were monitoring variations of the samples’ hydraulic conductivity at predetermined three different overburden pressures. The startup low pressure inflow was afterward altered by increasing the injection pressure up to the point at which hydraulic conductivity started to change at each run; we called it the threshold injection pressure. The corresponding hydraulic conductivity at such pressure was measured. As the increased permeability was a function of distance to the simulated recharge, it was deemed too beneficial to develop an equation to enable predicting this new hydraulic conductivity at different distances. Findings indicate that in uniformly graded sands under overburden pressure up to 68.64 kPa, the hydraulic conductivity in the threshold injection pressure—compared to its primary amount up to 45 cm from borehole wall—show a remarkable growth. However, this growth rate for greater distances up to 60 cm is negligible. Furthermore, in the threshold injection pressure, the hydraulic conductivity seems not to be time dependent. But, in constant injection pressures above the threshold injection pressure, the hydraulic conductivity shows some sort of time dependency. 相似文献
20.
Garth van der Kamp 《Hydrogeology Journal》2001,9(1):5-16
Shallow clay-rich aquitards limit groundwater recharge to underlying aquifers, but they also protect the aquifers from contamination.
The bulk hydraulic conductivity of such shallow aquitards can range from less than 1 mm/year to more than 100 m/year and may
be much greater than the hydraulic conductivity of small intact samples of the aquitard material. This enhanced hydraulic
conductivity diminishes the qualities of the aquitards for the protection of underlying aquifers but allows a higher rate
of recharge. For aquifers that are overlain by aquitards, management and protection of groundwater resources may be critically
dependent on reliable determinations of aquitard permeability.
A variety of methods for determining bulk hydraulic conductivities of shallow clay aquitards is available; each has drawbacks
and advantages, and each is based on simplifying assumptions. These methods include slug tests, pumping tests, response of
the aquitard to mechanical loading, and analysis of natural pore-pressure fluctuations. Several of the commonly used methods
require an independent measurement of specific storage. Laboratory methods for determining specific storage are probably not
representative of in situ conditions and may lead to overestimation of aquitard permeability. Much of the theory developed
to date depends on the assumption that horizontal displacement of the solid material is negligible, and this may not be a
valid assumption for highly deformable media such as clay aquitards. However, with judicious selection of the most suitable
methods for a particular site, good test design, careful instrumentation, and respect for the underlying assumptions, reliable
determinations of aquitard permeability can be obtained.
Electronic Publication 相似文献