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1.
泰斯模型的统计分析求解 总被引：4，自引：0，他引：4
本文利用统计分析来求解水文地质参数,原理简单,解是唯一的。其基本思想是利用非稳定流抽水试验获得的s-t系列资料,以泰斯公式为参考模型,建立试验系列的非线性统计模型,求解导水系数T和贮水系数μ 。统计模型既可利用目前先进的软件辅助求解,亦可利用一台可编程计算器完成计算。本文借助一个实例,应用MATLAB语言的统计分析工具的多元回归分析模块进行求解,获得了理想的结果。 相似文献
2.
Antonio Possolo 《Mathematical Geosciences》1983,15(1):207-210
The second-degree Taylor polynomial for a ratio is used to derive approximations to the means, variances, and covariances of proportions. 相似文献
3.
B. Van de Steen A. Vervoort J. A. L. Napier R. J. Durrheim 《Rock Mechanics and Rock Engineering》2003,36(2):143-161
Summary This paper investigates whether a micromechanical model developed to investigate the relation between the basic failure processes
at grain-scale and the macroscopic failure pattern can be applied to model the fracturing around large-scale excavations.
The simulated fracture pattern around a vertical shaft is compared to the fracturing around a shaft at a depth of 3400 m.
The simulations suggest that wedge-shaped zones, called dog-ears, are formed by a progressive splitting-like failure of the
rock. The fractures forming these slabs nucleate in the zones subjected to the highest compressive stresses. Both shear and
tensile mechanisms are responsible for the fracturing. The dog-ears deepen and widen as spalling continues.
Received June 5, 2001; accepted September 24, 2002; Published online January 21, 2003
Acknowledgements The simulations presented in this paper form part of the PhD study of B. Van de Steen at the KULeuven. The authors wish to
thank the sponsors of the Deepmine project for the permission to use the information pertaining to the fracturing around the
South shaft at Western Deep Levels.
Authors' address: André Vervoort, Katholieke Universiteit Leuven, Faculty of Engineering, Department of Civil Engineering, Kasteelpark Arenberg
40, B-3001 Leuven, Belgium; e-mail: andre.vervoort@bwk.kuleuven.ac.be 相似文献
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Processes and rates of weathering in representative tuff obtained from a Green Tuff region were directly examined using a new fluorescent approach. This approach was developed to visualize microscopically the microcracks and micropores that contribute to deterioration. The following observations were made. Progression of tuff weathering is caused by a delicate balance between chemical alteration and physical disintegration. Weathering occurs in many hidden microcracks and micropores not detected under natural light, but which can be clearly visualized under ultraviolet light. Water pathways, such as microcracks and cavities, accelerated the chemical alteration by increasing the effective surface area of rocks in contact with water. As the reaction proceeds, the constituent materials loosen and alteration products become widespread in the matrix. Secondary amorphous to poorly crystallized materials, such as iron hydroxide and aluminosilicate, precipitate on the fracture surfaces, slowing the progress of weathering. At the ultimate stage of weathering in tuff, all cracks and most of the micropores are filled with secondary materials. These observations on a microscopic scale during tuff weathering agree with the assessment of weathering obtained by measuring porosity, P-wave velocity and tensile strength. 相似文献
6.
A solution to the King liberation model is proposed and tested against the results of King and liberation of sphalerite, galena and chalcopyrite from a complex sulphide ore. For the King data, good agreement is shown. For the complex sulphide data, the trend is correct, but calibration is required for a close fit. A potentially important use of the model solution is to predict liberation size of an ore at the exploration stage. 相似文献
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Doklady Earth Sciences - 相似文献
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Travis G. Gerwing Diana J. Hamilton Myriam A. Barbeau Katy Haralampides Gordon Yamazaki 《Estuaries and Coasts》2017,40(3):717-725
The spillway gates of the Petitcodiac Causeway, a hydraulic structure ~35 km upstream of the mouth of the Petitcodiac River in New Brunswick, Canada, were permanently opened in April 2010. The short-term effect opening the spillway gates had on downstream intertidal mudflats of the upper Bay of Fundy was investigated. Specifically, a multivariate before-after-control-impact design was used to determine if opening the spillway gates affected the invertebrate community (crustaceans, polychaetes, and molluscs), abiotic sediment conditions (sediment water content, mean particle size, penetrability, and depth of the apparent redox potential discontinuity), or resource availability (sediment chlorophyll a concentration and organic matter content) of five intertidal mudflats (two impacted sites, three reference sites) spanning Chignecto Bay, the northern arm of the upper Bay of Fundy, up to 5 months post-opening. No biologically or statistically meaningful differences were detected between impacted and reference sites for any of the measured variables. This suggests that opening the causeway did not have a quantifiable impact on these intertidal mudflats, at least within half a year of the opening. This is likely a result of the macrotidal nature of the Bay of Fundy that overwhelmed any immediate changes to hydrodynamics that occurred after the opening of the causeway gates. 相似文献
10.
The dynamic response of a mechanically stabilized earth wall to the passing of a high‐speed train is modelled using the finite element method. A three‐dimensional analysis is carried out, using a specific framework that allows performing the analysis with a moderate computational effort. In the first place, a so‐called multiphase approach is used to take into account the reinforcing strips. The moving load is taken into account by performing the calculation in a mobile referential using the properties of symmetry of the train cars and a simplifying assumption of periodicity for the whole train. We also assume a steady state. A partial validation of the approach is obtained by means of a comparison with an analytical solution. The quick increase in displacements induced by the train passing when the speed comes close to the celerity of Rayleigh waves clearly appears in the results. The vertical displacements, vertical stresses in the backfill, tensile forces in the strips and the influence of the stiffness of the soil are discussed. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
11.
L.L. Chyi 《International Journal of Coal Geology》1997,33(4):317-331
The Harlem coal is postulated to have been deposited in raised-bog settings. It was initially deposited as low-sulfur peat, but groundwater of a later origin altered portions of it to high-sulfur coal. The total sulfur content of 172 samples from 31 locations on a moisture- and ash-free basis have a quadrimodal distribution with two major modes at 0.75% S and 2.0%S. Multiple sampling and analyses at specific mine sites indicate that the addition of sulfur of a later origin occurred either laterally adjacent to sandstone channels or vertically adjacent to faults. Significant sulfur addition also occurred above clay partings at these sites. The original low-sulfur nature is preserved where the coal bed is isolated from descending groundwater by a thick impervious layer. Trace-element analyses show high concentrations of mobile elements such as Na and Mn in the high-sulfur coals. 相似文献
12.
C.-L. Chang Y.-T. Lin 《International Journal of Environmental Science and Technology》2014,11(2):303-310
Water quality monitoring stations play critical roles for analyzing the information of water quality conditions in a watershed. The understanding of water quality conditions of a river system is very important for water resource management. This study applied the VIKOR method, a commonly used method in multiple criteria analysis, to evaluate the design of the water quality monitoring network in the Taipei Water Resource Domain (TWRD). Five criteria were selected for multiple criteria analysis: non-point source pollution, green cover ratio, landslide area ratio, over-utilization area ratio of hillsides, and density of water quality monitoring stations. This study recommended several areas where there is a need for sufficient monitoring records of water quality. The result shows that more monitoring stations are needed in the Bei-Shih Creek Basin. Although the Nan-Shih Creek Basin covers larger area than the Bei-Shih Creek Basin and the Sin-Dian Creek Basin, it can accept less density of water quality monitoring stations. 相似文献
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M. C. S. Humphreys M. Edmonds M. Plail J. Barclay D. Parkes T. Christopher 《Contributions to Mineralogy and Petrology》2013,165(1):191-215
The eruption of Soufrière Hills Volcano, Montserrat, has been ongoing since 1995. The volcano is erupting a crystal-rich hornblende-plagioclase andesite with ubiquitous mafic inclusions, indicating mixing with mafic magma. This mafic magma is thought to be the driving force of the eruption, supplying heat and volatiles to the andesite resident in the magma chamber. As well as producing macroscopic mafic inclusions, the magma mixing process involves incorporation of phenocrysts from the andesite into the mafic magma. These inherited phenocrysts show clear disequilibrium textures (e.g. sieved plagioclase rims and thermal breakdown rims on hornblende). Approximately 25 % of all phenocrysts in the andesite show these textures, indicating very extensive mass transfer between the two magma types. Fragments of mafic inclusions down to sub-mm scale are found in the andesite, together with mafic crystal clusters, which are commonly found adhered to the rims of phenocrysts with disequilibrium features. Mineral chemistry also points to the transfer of microlites or microphenocrysts, initially formed in the mafic inclusions, into the andesite. This combined evidence suggests that some of the mafic inclusions disaggregate during mingling and/or ascent, possibly due to shearing, and raises the question: What proportion of the andesite ‘groundmass’ actually originated in the mafic inclusions, and thus, what is the true amount of mafic magma in the magmatic system? We present a new method for quantifying the relative proportions of groundmass plagioclase derived from mafic and andesitic magma, based on analysis of back-scattered electron images of the groundmass. Preliminary results indicate that approximately 16 % of all groundmass plagioclase belongs genetically to the mafic inclusions. Together with the crystal clusters, disequilibrium phenocryst textures and mm-scale inclusions, there is a ‘cryptic’ mafic component in the andesite of approximately 6 % by volume. This is significant compared with the proportion of macroscopic mafic inclusions (typically ~ 1–5 %). The new method has the potential to allow tracking of the mafic fraction through time and thus to yield further insights into magma hybridisation processes. 相似文献
14.
Chris King 《Geology Today》2006,22(6):227-231
In the UK, the National Science week aims to bring exciting science to the public. As explained on the British Association (BA) website: 'National Science Week aims to celebrate science and its importance to our lives, giving people from everywhere in the UK the chance to participate in science activities and experiments and to engage in science discussions in their local area. … We encourage individuals and organisations to take part …' The Prime Minister has said: 'National Science Week is so important. It encourages people to engage with science through informative and fun events, and provides scientists with an opportunity to talk to people about their research and gain an understanding of the public's views.' Science Week provides a wonderful opportunity for geoscientists to bring their science to the public in ways that will inform and inspire. It takes a day, some preparation, and a willingness to 'be in the front line' of interaction with people of all ages. It needs an engaging jargon-free approach and activities that will 'draw in the punters' and provide them with experiences that they won't easily forget. This article shows ways in which it can be delivered. 相似文献
15.
This article describes a method that determines the position of a point relative to a fixed boundary. Its advantage over the other existing algorithms described below is that in most cases it is necessary that only part of the algorithm be executed to determine the position of the point. A possible inconvenience of using this algorithm is that the contour boundary has to be entered as data. For problems where the boundary often changes the algorithm is not suitable in its present form. The applications envisaged here are to cases where the position of a very large number of points have to be determined relative to one fixed polygonal boundary whose shape is known in advance, for example, blanking out of contours in automatic contouring, or selecting drill holes which lie in the particular part of a mineral deposit. 相似文献
16.
《Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy》2000,25(3):277-280
Detailed investigations of the ionospheric and magnetospheric perturbations induced by earthquakes, volcanic eruptions and strong man-made actions such as explosions and special supersonic flights indicated that those phenomena can not be accounted for in the traditional framework of the acoustic-gravity mechanisms. A clue can be found in the particular sensitivity of the electrical conductivity of the D- layer to weak stochastic perturbations of electron concentration. The calculations show that the electron Pedersen conductivity, which is usually small in the homogeneous ionosphere, increases drastically because of ionospheric irregularities.Some refined effects in the Extremely Low Frequency (ELF) and Very Low Frequency (VLF) ranges can be predicted. 相似文献
17.
The mechanical response of earth structures reinforced with steel strips to loads associated with rail traffic is not well known. In order to better understand the deformations induced by train loads, and to improve design methods, a full-scale structure was built, instrumented, and tested near Rouen, France. Finite-element analyses were performed both in plane-strain and three-dimensional conditions, using different approaches to account for the interaction between the strips and the backfill material. After calibration of the soil-strip interface parameters for a load of 90 kN, simulations of the wall response to a load of 850 kN provided results in good agreement with measurements. Numerical models showed that the soil-strip interface parameters have a major influence on the predicted behavior. The proposed approach could be used for further studies of the influence of geometric and mechanical parameters. 相似文献
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In the field of constitutive modelling of soil behaviour, optimisation techniques have been mostly employed as a calibration tool, particularly when several model parameters lack clear physical meaning. In this paper, however, a procedure based on a Hill-Climbing optimisation algorithm is presented as a form of improving the performance of constitutive models. Specifically, a simple cyclic nonlinear elastic model, which is shown to be unable to simulate adequately the damping ratio measured under small and large strain amplitudes, is modified by applying the Hill-Climbing technique to the determination of a new relationship describing the unloading/reloading behaviour of soil under cyclic loading. The performance of the proposed model is assessed by evaluating its parameters based on three distinct sets of empirical damping ratio curves and computing the corresponding error in their simulation. It is shown that the introduction of the new unloading/reloading expression formulated based on the outcome of the optimisation procedure increases substantially the precision of the constitutive model. 相似文献
20.
Miriam Billig 《GeoJournal》2016,81(1):123-137
The objective of this study was to understand the implications of forced displacement and resettlement of a rural community to an extremely different built environment in urban setting. Based on the Inglehart’s theory of cultural shifts we were able to delineate the process by which changes in physical environment caused significant changes in the community social structure and community members’ cultural identities. The collective characteristics that had once united and strengthened the community’s social structure began to dwindle. Meanwhile, a growing tendency towards individualistic characteristics gradually increased, causing the weakening and eventual dissolution of both the community and its social structure. The gradual process of community changes was reflected in the subjective narratives presented by community residents in a series of in-depth interviews conducted 4 years after the evacuation, in their new homes. Till that time, the community finally broke up, most of its members spreading out to live in various other areas. The study findings will be incorporated into a framework for resettlement policy on appropriate housing for resettled communities. 相似文献