Correction of the Buckingham–Darcy Law for flow of high strength salts in variably saturated porous media     

Erick R. Burns  Maria I. Dragila  John S. Selker  Ronald B. Guenther  Jean-Yves Parlange  Noam Weisbrod 《Advances in water resources》2007

The Buckingham–Darcy Law is used to describe fluid flow in unsaturated porous media at low Reynolds number. In order to provide a priori corrections to this law, a process thermodynamic approach is utilized to ascertain the functional dependence. Using this knowledge, corrections to the hydraulic conductivity coefficient are proposed and compared with available data. The proposed corrections substantially predict the observed behavior of flow of high concentration (saturated) sodium chloride solutions in porous media. During the derivation, physical principles consistent with the thermodynamics of the system were utilized. A review of these principles and their results provides an alternative form of the generalized Gibbs–Duhem Relation for continuous processes, indicating that the identical equivalence to zero is unlikely to occur for dissipative processes. Further, the postulated Gibbs and Gibbs–Duhem Relations indicate that special differential operators need to be used for continuous processes rather than the usual use of a generic differential.  相似文献   

Contribution of stable isotopes to the understanding of the unsaturated zone of a carbonate aquifer (Nerja Cave, southern Spain)     

Francisco Carrasco  Bartolom Andreo  Cristina Lin  Jacques Mudry 《Comptes Rendus Geoscience》2006,338(16):1203-1212

We analysed the stable isotopes (¹⁸O and ²H) of rainwater and drip water within a cave (Nerja Cave) located in the unsaturated zone of a carbonate aquifer. Rainfall is more abundant and presents lower isotopic content in winter, while the volume of drip water is greater and its isotopic content is lower in summer. The flow analysis of ¹⁸O through the unsaturated zone confirms the seasonal lag between rainfall and the appearance of drip water in the cave and reveals that the unsaturated zone of the aquifer, in the sector of the cave, behaves like an inertial system with a strong capability to modulate the input signal. To cite this article: F. Carrasco et al., C. R. Geoscience 338 (2006).  相似文献   

Analysis of the landslide triggering mechanism during the storm of 20th–21st November 2000, in Northern Tuscany     

N. Casagli  S. Dapporto  M. L. Ibsen  V. Tofani  P. Vannocci 《Landslides》2006,3(1):13-21

A severe rainstorm of high intensity occurred on 20th–21st November 2000, in the region of Pistoia, Tuscany, Italy, which triggered, within the entire province, over 50 landslides. These landslides can be broadly defined as complex earth slides—earth flows, originating as rotational slides that develop downslope into a flow. In this paper, two such landslides have been investigated by modelling the process of rainwater infiltration, the variations in both the positive and negative pore water pressures and their effect on slope stability during the storm. For both sites, results from morphometric and geotechnical analyses were used as a direct input to the numerical modelling. A modified Chu, 1978 approach was used to estimate the surface infiltration rate by adapting the original Green and Ampt, 1911 equations for unsteady rainfall intensity in conjunction with the surficial water balance. For transient conditions, a finite element analysis was used to model the fluctuations in pore water pressure during the storm, with the computed surface infiltration rate as the surface boundary condition. This was then followed by the application of the limit equilibrium Morgenstern and Price, 1965 slope-stability method, using the temporal pore water pressure distributions derived from the seepage analysis. From this methodology, a trend for the factor of safety was produced for both landslide sites. These results indicate that the most critical time step for failure was a few hours following the rainfall peak.  相似文献   

A 2‐D constitutive model for cyclic interface behaviour     

Giuseppe Mortara  Marc Boulon  Vito Nicola Ghionna 《国际地质力学数值与分析法杂志》2002,26(11):1071-1096

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砂砾性低渗气层水锁效应及减轻方法的试验研究   总被引：4，自引：0，他引：4  

张琰  崔迎春 《地质与勘探》2000,36(1):92-95

采用来自胜利油田的岩样,通过水锁效应对岩样渗透率影响的试验研究证实了水锁效应是导致砂砾性低渗气层损害的主要原因之一。然后对油田常用的表面活必地表面张力的测定,并在此基础上进行了优选,最后对用表面活性剂减轻岩样水锁效应的效果进行了评价试验。  相似文献   

Unconventional Energy Resources and Geospatial Information: 2006 Review   总被引：1，自引：1，他引：0  

American Association of Petroleum Geologists  Energy Minerals Division 《Natural Resources Research》2007,16(3):243-261

This article contains a brief summary of some of the 2006 annual committee reports presented to the Energy Minerals Division (EMD) of the American Association of Petroleum Geologists. The purpose of the reports is to advise EMD leadership and members of the current status of research and developments of energy resources (other than conventional oil and natural gas that typically occur in sandstone and carbonate rocks), energy economics, and geospatial information. This summary presented here by the EMD is a service to the general geologic community. Included in this summary are reviews of the current research and activities related to coal, coalbed methane, gas hydrates, gas shales, geospatial information technology related to energy resources, geothermal resources, oil sands, and uranium resources.

American Association of Petroleum Geologists, Energy Minerals DivisionEmail:

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某铜矿尾矿砂力学特性研究和稳定性分析   总被引：11，自引：4，他引：7  

张超  杨春和  孔令伟 《岩土力学》2003,24(5):858-862

在揭示某铜矿尾矿坝坝体材料空间分布状态及其力学特性的基础上,利用自动搜索的电算程序STED,分析计算了尾矿坝的整体与局部稳定性,得出一些结论,可为治理方案提供科学依据和技术指导。  相似文献   

喷浆桩技术在粗砂砾砂地层中的应用     

罗长军  任泽垠  卢冰 《岩土力学》2003,24(5):786-789

白河第三级橡胶坝直接座于河床上,饱水、强透水性。鉴于该坝水毁教训,在加长的混凝土水平防渗铺盖前缘,新增悬挂式帷幕垂直防渗措施,以便进一步达到防渗抗冲的目的。通过喷浆桩的试验及施工,说明该项技术应用于粗砂、砾砂地层中是可行的。针对施工中遇到的大量跑浆、冒浆、夹砂等难题亦进行了探讨。  相似文献   

Snow hydrology of a constructed watershed in the Athabasca oil sands region,Alberta, Canada          下载免费PDF全文

Scott J. Ketcheson  Jonathan S. Price 《水文研究》2016,30(14):2546-2561

Wetlands are now being integrated into oil sands mining landscape closure design plans. These wetland ecosystems will be constructed within a regional sub‐humid climate where snowfall represents ~25% of annual precipitation. However, few studies focus on the distribution of snow and, hence, the storage of winter precipitation in reclaimed oil sands landscapes. In this study, the distribution, ablation and fate of snowmelt waters are quantified within a constructed watershed in a post‐mining oil sands environment. Basin‐averaged peak SWE was 106 mm, with no significant difference between reclaimed slopes with vegetation and those that were sparsely vegetated or bare. Snow depth was greatest and more variable near the toe of slopes and became progressively shallower towards the crest. Snow ablation started first on the vegetated slope, which also exhibited the maximum observed ablation rates. This enhanced melt was attributed to increased absorption of short‐wave radiation by vegetation stems and branches. Recharge to reclaimed slopes and a constructed aquifer during the snowmelt period was minimal, as the presence of ground frost minimized infiltration. Accordingly, substantial surface run‐off was observed from all reclaimed slopes, despite being designed to reduce run‐off and increase water storage. This could result in increased flashiness of downstream watercourses during the spring freshet that receive run‐off from post‐mining landscapes where large reclaimed slopes are prolific. Run‐off ratios for the reclaimed slopes were between 0.7 and 0.9. Thus, it is essential to consider snow dynamics when designing landscape‐scale constructed ecosystems. This research demonstrates that the snowmelt period hydrology within reclaimed landscapes is fundamentally different from that reported for natural settings and represents one of the first studies on snow dynamics in constructed watershed systems in the post‐mined oil sands landscape. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Predicting the initiation of static liquefaction of cross‐anisotropic sands under multiaxial stress conditions          下载免费PDF全文

Xilin Lü  Maosong Huang  José E. Andrade 《国际地质力学数值与分析法杂志》2017,41(17):1724-1740

Experimental evidence has shown that the liquefaction instability of sands can be affected by its material density, stress state, and inherent anisotropy. In order to predict the initiation of the static liquefaction of inherent cross‐anisotropic sands under multidimensional stress conditions, a rational constitutive model is needed. An elastoplasticity model able to capture the influences of intermediate principal stress ratio (b  = (σ ₂ ? σ ₃)/(σ ₁ ? σ ₃)) and loading direction on stress–strain relationships and volumetric properties was proposed. The yield function was formulated to be controlled by Lode angle, loading direction, and material state; the stress–dilatancy was a material state‐dependent function. After using the existing drained hollow cylinder tests to validate the proposed model, this model was used to simulate the existing undrained hollow cylinder tests. During this simulation, the second‐order work criterion was used to determine the initiation of static liquefaction. The results showed that an increase in both the intermediate principal stress ratio and the loading angle induces a decrease in the second‐order work. Static liquefaction is initiated more easily at a stress state with a large intermediate principal stress ratio and a large loading angle, and the mobilized friction angle at the instability points decreases with the intermediate principal stress ratio and the loading angle. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献