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1.
地层孔隙水含量的计算主要受地层孔隙度与孔隙含水饱和度的影响.通过实验室煤层及其顶底板岩芯物理测试与孔隙度测量,可以获得煤系地层岩芯的孔隙度与岩芯纵、横波速度的经验公式;结合三分量地震勘探获得的纵波与横波速度,能够计算出煤系地层的孔隙度;含水饱和度的计算通过实验室岩电参数测试和阿尔奇公式可以计算得到.结合淮南某矿区三维三分量地震勘探和地球物理测井及岩样的岩电试验,实现了三维空间煤系地层孔隙含水体积百分比的精确计算.该预测方法与传统的、钻孔控制的地下水评价方法相比可以提供相对精细的、三维空间的、定量化的煤系地层孔隙相对含水量,对煤炭与煤层气资源开采中所涉及的地下水分布规律预测有一定的参考意义. 相似文献
2.
S. H. Luk 《地球表面变化过程与地形》1979,4(3):241-255
This paper describes laboratory testing of 148 samples collected from Southern Alberta for erosion by wash and splash. Rainfall intensity was held constant during these tests. Soil aggregation was the most significant variable explaining soil loss. The significance of other soil properties, such as organic carbon and clay content is variable, depending on the interrelationships among aggregate stability, organic content, and clay content of particular soils. Variations in erodibility of the major soils examined are explained by the resistance of aggregates to compaction and dispersion. Splash detachment and wash transport are the dominant erosion mechanisms in inter-rill areas. 相似文献
3.
饱和砂土最大动剪切模量的不同试验对比研究 总被引：1，自引：0，他引：1
对233个饱和砂土土样室内试验确定的最大动剪切模量和同一位置现场原位试验确定的最大动剪切模量进行了对比研究。结果表明：两者相差很大,室内试验结果基本上小于现场试验结果,埋藏深的土样相差更大;室内试验的最大动剪切模量与深度符合幂函数规律,且与砂土的密实度有关,与砂土的颗粒成分关系不大。通过工程实例,比较了2种试验最大动剪切模量对地震反应分析的影响,得到了室内试验最大动剪切模量与现场剪切波速的统计经验关系式。该经验关系式对工程场地地震反应分析具有一定的参考应用价值。 相似文献
4.
Peter Nozharov Nikolai Petkov Slavcho Yanev Vladimír Kropáček Miroslav Krs Petr Pruner Reviewer J. Pícha 《Studia Geophysica et Geodaetica》1980,24(3):252-284
Summary In order to obtain basic palaeomagnetic data on Upper Carboniferous, Permian and Triassic sediments collected from the NW Bulgaria, laboratory stability tests were extended from A.C. and thermal treatments to studies of mineral phase changes and to investigations of changes of magnetic anisotropy during laboratory procedures. Laboratory criteria were found which permitted to distinguish samples suitable for palaeomagnetic analyses from those representing rocks totally or almost totally chemically reworked during their history. Palaeomagnetic directions and pole positions derived from Stephanian, Lower Permian and Triassic rocks from the southern margin of the Moesian Platform are compatible with the values obtained for the tectonically stable North-European Platform. 相似文献
5.
L. Joseph Bachman 《Ground water》1984,22(4):460-467
Field and laboratory analyses of pH, alkalinity, and specific conductance from water samples collected from the Columbia aquifer on the Delmarva Peninsula in eastern Maryland were compared to determine if laboratory analyses could be used for making regional water-quality interpretations. On the basis of 170 field pH and specific conductance measurements, 165 laboratory pH and specific conductance measurements, and 86 field and 135 laboratory alkalinity measurements, a significant difference at the 0.1-percent level was found between laboratory and field analyses of pH and specific conductance. No significant difference was found between laboratory and field analyses of alkalinity. In most samples, laboratory pH was greater than field pH, laboratory specific conductance was less than field specific conductance, and laboratory alkalinity was equally likely to be less than, the same as, or greater than field alkalinity. Kruskal-Wallis tests of field and laboratory data grouped by north-south and east-west coordinates and by land use indicate that the difference between field and laboratory values is usually not enough to affect the outcome of the statistical tests. Thus, laboratory measurements of these constituents may be adequate for making certain regional water-quality interpretations, although they may result in errors if used for geochemical interpretations. 相似文献
6.
The analyses which have so far been made of volcanic gases have only given instantaneous measurements of the composition of the gas phase which, however, is likely to be variable during periods of eruptive activity. A first step towards the continuous measurement of fluctuations in the composition of the gas phase during eruptions was made in 1963, by the use of sampling tubes permitting the rapid determination in the field of individual components of gaseous emanations. Since then, a technique has been developed of collecting samples of volatile constituents and preserving them for subsequent analyses in the laboratory. On the other hand, a technique has been developed for continuous sampling with a distant recording mechanism, which permits the study of the dynamics of eruptive phenomena. The first results of observations on several different types of emanations (submarine, high and low temperature fumaroles, and gas discharges from basalt flows) may considered satisfactory. The present paper is intended to encourage volcanologists concerned with the study of eruptive phenomena to employ new methodes for the study of this problem. The analysis of the eruptive mechanisms should start with a simultaneous observation and recording of the greatest possible number of parameters. The gas phase is of fundamental importance in the eruptive phenomena. It is therefore indispensable to understand its variations with time, both rapid and slow. It is very important to be able to show, on the same diagram, curves representing the simultaneous variations of all the measurable parameters, chemical, physical, and mechanical. 相似文献
7.
In situ denitrification relies on indigenous microorganisms to reduce nitrate to N(2) gas. However, when initial nitrate concentrations are large, produced gas volumes also can be very large, potentially resulting in reduced water saturation and hydraulic conductivity in the treatment zone. In this study, we investigated the fate of N(2) and other gases produced during denitrification in a laboratory flow cell containing packed sediment. Denitrifying activity was stimulated by additions of nitrate and ethanol. Microbial activity was monitored by measuring nitrate, nitrite, and ethanol concentrations; gas saturations were measured during the experiment using a gamma imaging system. Biomass was measured using phospholipid fatty acid analysis of sediment samples. Bioenergetic calculations calibrated to measured nitrate consumed and biomass produced predicted that 1.2 L N(2) gas/L water should have been produced following the addition of 100 mM nitrate. However, the maximum measured gas saturation was only 23%, indicating substantial gas loss from the sediment pack. Temporal gamma images and visual observations confirm that small gas bubbles formed in the sediment pack coalesced into larger bubbles and migrated upward through gas-filled channels to the sediment pack surface. Although gas saturations increased, there was no significant change in sediment pack hydraulic conductivity. These results suggest that in permeable reactive barriers used for in situ denitrification, gas production will not necessarily lead to unlimited gas accumulation in the pore space and that the effects of gas production on water saturation and hydraulic conductivity may be relatively minor. 相似文献
8.
S. Vinciguerra C. Trovato P.G. Meredith P.M. Benson C. Troise G. De Natale 《Pure and Applied Geophysics》2006,163(10):2205-2221
We report laboratory measurements of P- and S-wave velocities on samples of tuff from Campi Flegrei (Italy), and a new tomographic
velocity map of the Campi Flegrei caldera. Laboratory measurements were made in a hydrostatic pressure vessel during both
increasing and decreasing effective pressure cycles. Selected samples were also thermally stressed at temperatures up to 600°C
to induce thermal crack damage. Acoustic emission output was recorded throughout each thermal stressing experiment, and velocities
were measured after thermal stressing. Laboratory P- and S-wave velocities are initially low for the tuff, which has an initial
porosity of ~45%, but both increase by between 25 and 50% over the effective pressure range of 5 to 80 MPa, corresponding
to a decrease of porosity of ~70%. Marked velocity hysteresis, due to inelastic damage processes, is also observed in samples
subjected to a pressurization-depressurization cycle. Tomographic seismic velocity distributions obtained from field recordings
are in general agreement with the laboratory measurements. Integration of the laboratory ultrasonic and seismic tomography
data indicates that the tuffs of the Campi Flegrei caldera can be water or gas saturated, and shows that inelastic pore collapse
and cracking produced by mechanical and thermal stress can significantly change the velocity properties of Campi Flegrei tuffs
at depth. These changes need to be taken into account in accurately interpreting the crustal structure from tomographic data. 相似文献
9.
Todd A. McAlary Paul Nicholson Hester Groenevelt David Bertrand 《Ground Water Monitoring & Remediation》2009,29(1):144-152
Soil-gas sampling and analysis is a common tool used in vapor intrusion assessments; however, sample collection becomes more difficult in fine-grained, low-permeability soils because of limitations on the flow rate that can be sustained during purging and sampling. This affects the time required to extract sufficient volume to satisfy purging and sampling requirements. The soil-gas probe tubing or pipe and sandpack around the probe screen should generally be purged prior to sampling. After purging, additional soil gas must be extracted for chemical analysis, which may include field screening, laboratory analysis, occasional duplicate samples, or analysis for more than one analytical method (e.g., volatile organic compounds and semivolatile organic compounds). At present, most regulatory guidance documents do not distinguish between soil-gas sampling methods that are appropriate for high- or low-permeability soils. This paper discusses permeability influences on soil-gas sample collection and reports data from a case study involving soil-gas sampling from silt and clay-rich soils with moderate to extremely low gas permeability to identify a sampling approach that yields reproducible samples with data quality appropriate for vapor intrusion investigations for a wide range of gas-permeability conditions. 相似文献
10.
Jan Vilhelm Vladimír Rudajev Roman Živor Tomáš Lokajíček Zdeněk Pros 《Geophysical Prospecting》2010,58(6):1099-1110
The purpose of this paper is the comparison of P‐wave velocity and velocity anisotropy, measured at different scales under laboratory and field conditions. A shallow seismic refraction survey with shot/receiver spacing of up to 10 m was carried out on a flat outcrop of lhertzolite in the southern part of the Balmuccia massif. Oriented rock samples were also obtained from the locality. The particular advantage of the laboratory method used is the possibility of measuring velocity in any direction under controlled conditions. Laboratory tests were made on spherical peridotite samples, 50 mm in diameter, by ultrasonic velocity measurements in 132 directions (meridian and parallel networks) under confining stress ranging from atmospheric to 400 MPa. The mean P‐wave velocity of the field and laboratory data differed by between 20–30%. In addition, P‐wave velocity anisotropy of 25% was detected in the field data. Whereas the anisotropy in the laboratory samples in the same orientation as the field surveys was less than 2%. This observed scaling factor is related to the different sampling sizes and the difference in frequencies of applied elastic waves. With an ultrasonic wavelength of 10 mm, laboratory samples represent a continuum. The field velocities and velocity anisotropy reflect the presence of cracks, which the laboratory rock samples do not contain. Three sub‐vertical fracture sets with differing strikes were observed in the field outcrop. Estimates of fracture stiffness from the velocity anisotropy data are consistent with other published values. These results highlight the difficulty of using laboratory velocity estimates to interpret field data. 相似文献
11.
Vladimír Čermák Věra Vaňková Milan Matolín Jiří Bartošek Reviewer A. Janáčková 《Studia Geophysica et Geodaetica》1977,21(1):70-80
Summary The paper discusses the obvious experimental relation between the laboratory determinations of total gamma-ray activity, expressed in equilibrium uranium concentration, and heat production due to radioactive decay. The heat production data were calculated by means of the concentrations of uranium, thorium and potassium determined spectrometrically, together with the conversion factors into the rate of heat generation. The obtained relation may help define the typical heat production for characteristic surface rocks and estimate their contribution in heat flow study. Between the gamma-ray activity recorded during aeroradiometric mapping and the laboratory radiometric measurements of surface rock samples, there is also an experimental relation, which can be used further in estimating the value of surface heat production at a chosen locality. 相似文献
12.
Contamination of Hospital Wastewater with Hazardous Compounds as Defined by § 7a WHG In total, 45 samples of hospital wastewater obtained from different origins (total wastewater, nursing, and laboratories) were investigated using chemical analyses as well as biological testing methods. In parallel, the consumption of several product groups relevant to the wastewater has been calculated. The water consumption strongly influenced the quality of the corresponding wastewater. Most of the values of the chemical parameters determined were found within a range as would have been expected for municipal wastewater. The AOX concentrations were distinctly elevated (0.41 mg/L in total wastewater and 0.95 mg/L in nursing wastewater). As could be shown by the calculated consumption of different compounds, the iodoferous X-ray contrast media represented a predominant proportion of the total AOX load of the clinical wastewaters tested. The values of some of the total wastewater samples and the laboratory wastewater samples showed a high toxicity as determined using the daphnia and luminescent bacteria tests. Using Ames and hamster cell tests, 5 out of 23 samples in the clinical area and 7 out of 9 samples from the laboratories turned out to be mutagenic. The origin of this mutagenic potential could not be determined though. 相似文献
13.
A. V. Kiryukhin E. P. Kaymin E. V. Zakharova 《Journal of Volcanology and Seismology》2007,1(6):429-438
Thermal-hydrodynamic modeling was used to reproduce laboratory tests involving sandstone samples collected from a deep radionuclide
repository site at the Siberia Chemical Plant, Seversk (Russia). Laboratory tests included injection of alkaline fluids into
sandstone samples at 70°C. Some minerals were forced in the model to precipitate or dissolve, according to laboratory test
results. Modeling results were compared with observed test data (mineral phase changes, transient concentration data at the
outlet of a sample column). Reasonable agreement was obtained between calculated and measured mineral phases (Na-smectite
and kaolinite precipitation; quartz, microcline, chlorite, and muscovite dissolution). After the cation exchange option used
in the model, the most abundant secondary mineral generated was dawsonite, which corresponds to sodium carbonates observed
in the sample after the injection test. Time-dependent chemical concentrations (transient chemical concentration data) at
the outlet of the sample column were qualitatively matched to the data observed.
The text was submitted by the authors in English. 相似文献
14.
A model for presentation of seismic pore water pressures 总被引：3，自引：0，他引：3
Tomislav Iv&#x;i&#x; 《Soil Dynamics and Earthquake Engineering》2006,26(2-4):191-199
A model for presentation of pore water pressures induced in sand samples during cyclic undrained testing is described. The proposed model belongs to a class of so-called ‘damage parameter models’, which correlate the pore pressure rise with a parameter based on an accumulated variable during testing. The concept of threshold strain is also incorporated in the model. The model has been verified on several series of published cyclic test data. Its parameters lie in a narrow band for a wide range of sand properties. The empirical functions that represent the common shape of individual curves for interpreted pore pressure data are also suggested. The proposed procedure has been adapted for presentation of other cyclic soil tests, and examples of interpretation of cyclic stress-controlled as well as cyclic drained tests are included. 相似文献
15.
The heterogeneous distribution of fluids in patchy-saturated rocks generates significant velocity dispersion and attenuation of seismic waves. The mesoscopic Biot–Rayleigh theory is used to investigate the relations between wave responses and reservoir fluids. Multiscale theoretical modeling of rock physics is performed for gas/water saturated carbonate reservoirs. Comparisons with laboratory measurements, log and seismic data validate the rock physics template. Using post-stack and pre-stack seismic inversion, direct estimates of rock porosity and gas saturation of reservoirs are obtained, which are in good agreement with oil production tests of the wells. 相似文献
16.
Sergei Stanchits Jerome Fortin Yves Gueguen Georg Dresen 《Pure and Applied Geophysics》2009,166(5-7):843-868
We investigated initiation and propagation of compaction bands (CB) in six wet and four dry Bentheim sandstone samples deformed in axial compression tests with strain rates ranging from 3.2 × 10?8 s?1 to 3.2 × 10?4 s?1. Circumferential notches with 0.8-mm width and 5-mm depth served to initiate CB at mid-sample length. Wet samples were saturated with distilled water and deformed at 195 MPa confining pressure and 10 MPa pore pressure. Dry samples were deformed at 185 MPa confining pressure. Twelve P-wave sensors, eight S-wave sensors and two pairs of orthogonally oriented strain-gages were glued to the sample surface to monitor acoustic emission (AE), velocities and local strain during the loading process. Nucleation of compaction bands is indicated by AE clusters close to the notch tips. With progressive loading, AE activity increased and AE hypocenters indicated propagation of a single CB normal to the sample axis. CB propagation from the sample periphery towards the centre was monitored. Microstructural analysis of deformed samples shows excellent agreement between location of AE clusters and CBs. In both dry and wet samples the lateral propagation of CBs was about 100 times faster than axial shortening rates. At the slowest displacement rate, AE activity during band propagation was reduced and CB nucleation in wet samples occurred at 20% lower stresses. This may indicate an increasing contribution of stress corrosion processes to the formation of the compaction bands. In dry and wet samples inelastic compaction energy per area ranged between 16 and 80 kJ m?2. This is in good agreement with previous estimates from laboratory and field studies. 相似文献
17.
Robert C. Buchmiller 《Ground Water Monitoring & Remediation》1989,9(3):126-130
A portable gas chromatograph was used to screen 32 ground water samples for volatile organic compounds. Seven screened samples were positive; four of the seven samples had volatile organic substances identified by second-column confirmation. Four of the seven positive, screened samples also tested positive in laboratory analyses of duplicate samples. No volatile organic compounds were detected in laboratory analyses of samples that headspace screening indicated to be negative. Samples that contained volatile organic compounds, as identified by laboratory analysis, and that contained a volatile organic compound present in a standard of selected compounds were correctly identified by using the portable gas chromatograph. Comparisons of screened-sample data with laboratory data indicate the ability to detect selected volatile organic compounds at concentrations of about 1 microgram per liter in the headspace of water samples by use of a portable gas chromatograph. 相似文献
18.
Softening and strength loss of sands with increasing excess pore water pressure under repeated loads is well-known. However, extensive damage to the built environment also occurs at the sites underlain by fine grained soils during seismic shaking. The primary objective of this study is to investigate the factors affecting cyclic behavior of saturated low-plastic silt through laboratory testing. For this purpose, an extensive laboratory testing program including conventional monotonic and cyclic triaxial tests was carried out over reconstituted silt samples. The effects of the inherent soil properties and the effects of loading characteristics on the cyclic response of saturated low-plastic reconstituted silt samples were examined separately. Based on the test results, a model was introduced to estimate the effect of initial shear stress on the cyclic response. Besides, liquefaction susceptibility of the samples was examined via current liquefaction susceptibility criteria. 相似文献
19.
Settlements under consecutive series of cyclic loading 总被引：1，自引：0，他引：1
Hüseyin Y&#x;ld&#x;r&#x;m Hayreddin Eran 《Soil Dynamics and Earthquake Engineering》2007,27(6):577-585
In this study, consolidation settlements of soft clay caused by cyclic loading and the affecting factors such as number of cycles and stress level were experimentally investigated. A group of samples prepared in slurry consolidometer in the laboratory were tested using cyclic simple shear testing device. Normally consolidated samples were subjected to five consecutive series of cyclic loading and drainage for 60 min were applied between each cyclic loading stages. Cyclic tests were performed with stress controlled two-way sinusoidal wave loading with different stress levels and number of cycles. Frequency of cyclic loading was constant as 0.1 Hz. As a result of this study, it can be concluded that soft clays subjected to undrained cyclic loading and drainage cycles exhibit more resistance against subsequent cyclic shear stresses. The consolidation settlements, pore pressures and shear strains decrease after each stage of cyclic loading. 相似文献