Numerical modelling of in situ behaviour of the Callovo–Oxfordian argillite subjected to the thermal loading     

Y. Jia  H.B. Bian  G. Duveau  K. Su  J.F. Shao   《Engineering Geology》2009,109(3-4):262-272

To enhance the understanding of thermal impact on the in situ behaviour of the Callovo–Oxfordian argillite, this paper presents an interpretation of an in situ heating experiment carried out in the Meuse/Haute Marne Underground Research Laboratory (M/HM URL). The argillite was heated successively by two constant heating powers: 277 W and 925 W. When subjected to thermal loading, the argillite exhibits an important volume change and a strong pore pressure response that significantly affect its hydraulic and mechanical behaviour. Numerical analysis has been performed by using a coupled theoretical formulation that incorporates a constitutive model especially developed for this material. Based on Biot's theory, this model includes the influence of interstitial pressure on the mechanical behaviour. The simulation obtained reproduces satisfactorily the results of the in situ experiment and the main observed patterns of behaviour. The interpretation and discussion of numerical results provide additional data that can help us to understand the thermo-hydromechanical behaviour concepts of saturated argillite formation.  相似文献   

A comparative simulation study of coupled THM processes and their effect on fractured rock permeability around nuclear waste repositories     

Jonny Rutqvist  Deborah Barr  Jens T. Birkholzer  Kiyoshi Fujisaki  Olaf Kolditz  Quan-Sheng Liu  Tomoo Fujita  Wenqing Wang  Cheng-Yuan Zhang 《Environmental Geology》2009,57(6):1347-1360

This paper presents an international, multiple-code, simulation study of coupled thermal, hydrological, and mechanical (THM) processes and their effect on permeability and fluid flow in fractured rock around heated underground nuclear waste emplacement drifts. Simulations were conducted considering two types of repository settings (1) open emplacement drifts in relatively shallow unsaturated volcanic rock, and (2) backfilled emplacement drifts in deeper saturated crystalline rock. The results showed that for the two assumed repository settings, the dominant mechanism of changes in rock permeability was thermal–mechanically induced closure (reduced aperture) of vertical fractures, caused by thermal stress resulting from repository-wide heating of the rock mass. The magnitude of thermal–mechanically induced changes in permeability was more substantial in the case of an emplacement drift located in a relatively shallow, low-stress environment where the rock is more compliant, allowing more substantial fracture closure during thermal stressing. However, in both of the assumed repository settings in this study, the thermal–mechanically induced changes in permeability caused relatively small changes in the flow field, with most changes occurring in the vicinity of the emplacement drifts.  相似文献   

高放射性核废物地质处置库场址预选和矿产资源勘查的关系     

朱立  王秀娟  曾志  程建平  王永江  王晓亮  王青海 《地质通报》2009,28(203):354-358

据1999—2007年资料的不完全统计,甘肃省地勘部门在北山地区一共投入4488.2万元人民币,矿产资源潜在价值估计为13.28亿元。一旦把甘肃省北山列为高放废物处置库的预选区,则潜在的经济损失将会很大,还可能影响西北地区的土地利用程度和经济发展。核试验场有多种围岩可供处置库地质选址选择,而且远离国境线与居民区,有利于高放废物处置库的安全管理。结合中国国情,在地质和社会条件有利的核试验军事禁区开展国家高放废物处置库的预选场址工作有独特的优势。提出了尽快在中国核试验场址开展高放废物地质处置库场址预选工作的建议。  相似文献   

Circulation of bubbly magma and gas segregation within tunnels of the potential Yucca Mountain repository     

Thierry Menand  Jeremy C. Phillips  R. Stephen J. Sparks 《Bulletin of Volcanology》2008,70(8):947-960

Following an intersection of rising magma with drifts of the potential Yucca Mountain nuclear waste repository, a pathway is likely to be established to the surface with magma flowing for days to weeks and affecting the performance of engineered structures located along or near the flow path. In particular, convective circulation could occur within magma-filled drifts due to the exsolution and segregation of magmatic gas. We investigate gas segregation in a magma-filled drift intersected by a vertical dyke by means of analogue experiments, focusing on the conditions of sustained magma flow. Degassing is simulated by electrolysis, producing micrometric bubbles in viscous mixtures of water and golden syrup, or by aerating golden syrup, producing polydisperse bubbly mixtures with 40% of gas by volume. The presence of exsolved bubbles induces a buoyancy-driven exchange flow between the dyke and the drift that leads to gas segregation. Bubbles segregate from the magma by rising and accumulating as a foam at the top of the drift, coupled with the accumulation of denser degassed magma at the base of the drift. Steady-state influx of bubbly magma from the dyke into the drift is balanced by outward flux of lighter foam and denser degassed magma. The length and time scales of this gas segregation are controlled by the rise of bubbles in the horizontal drift. Steady-state gas segregation would be accomplished within hours to hundreds of years depending on the viscosity of the degassed magma and the average size of exsolved gas bubbles, and the resulting foam would only be a few cm thick. The exchange flux of bubbly magma between the dyke and the drift that is induced by gas segregation ranges from 1 m³ s⁻¹, for the less viscous magmas, to 10⁻⁸ m³ s⁻¹, for the most viscous degassed magmas, with associated velocities ranging from 10⁻¹ to 10⁻⁹ m s⁻¹ for the same viscosity range. This model of gas segregation also predicts that the relative proportion of erupted degassed magma, that could potentially carry and entrain nuclear waste material towards the surface, would depend on the value of the dyke magma supply rate relative to the value of the gas segregation flux, with violent eruption of gassy as well as degassed magmas at relatively high magma supply rates, and eruption of mainly degassed magma by milder episodic Strombolian explosions at relatively lower supply rates.  相似文献   

Geologic site characterization for deep nuclear waste disposal in fractured rock based on 3D data visualization     

S. A. Tirn  P. Askling  S. Wnstedt 《Engineering Geology》1999,52(3-4):319-346

  相似文献   

A Spatial-Temporal/3-D Model for Volcanic Hazard Assessment: Application to the Yucca Mountain Region, Nevada     

Chih-Hsiang Ho  Eugene I. Smith 《Mathematical Geology》1998,30(5):497-510

We present a 3-D Poisson model that permits identification and quantification of volcanic phenomena distributed through space and evolving in time (i.e., spatiotemporal data). Specifically, the model: (1) is volcanologically informative in solving problems of volcanic risk/hazard which depends on the location and time of future events; (2) contains model fitting computation algorithms that are efficient; and (3) is flexible enough to handle a large class of volcanic risk/hazard studies. Furthermore, we apply the model fitting techniques developed in this paper to the volcanic data from the Yucca Mountain project to demonstrate a unified volcanic hazard analysis. This study also evaluates the sensitivity of the statistical models developed by experts who have addressed the volcanic hazard/risk assessment problem near the Yucca Mountain region.  相似文献   

Borehole Sealing Project at the Grimsel Test Site     

Peter Blümling 《Geotechnical and Geological Engineering》2005,23(6):843-858

Within the context of the phase IV (1994–1996) research and development activities at the Grimsel Test Site (GTS), Nagra developed, in collaboration with the Agence Nationale pour la Gestion des Déchets Radioactifs (Andra), an investigation project for the sealing of boreholes drilled from underground. The project had the following goals:

–	sealing of boreholes drilled from underground facilities with a length of up to 500 m,
–	sealing of boreholes with mainly irregular shape (e.g. breakouts of borehole wall),
–	ensuring a hydraulic conductivity of 10−11–10−12 m/s for the seal,
–	ensuring reliable quality control in routine production.

The new concept developed in this project was to use highly compacted bentonite pellets only. The two techniques tested were

(1)	pneumatic injection of pellets into a borehole using a grain size distribution of 4–10 mm,
(2)	emplacement using a modified core barrel for transport and compaction of the pellets.

Both techniques were tested in situ at the GTS to estimate their performance under realistic field conditions. The swelling pressures were monitored for 4 months after seal emplacement until an almost constant value was attained. Finally the hydraulic and mechanical performance of the seal was tested. It was found that the conductivities measured across the seal were equivalent to the matrix properties of the surrounding rock (2–5 × 10⁻¹² m/s). The hydraulic testing also showed no linear preferential flow.  相似文献   

高放废物处置库新疆雅满苏和天湖预选地段地下水同位素特征及其指示意义   总被引：1，自引：0，他引：1  

郭永海  李娜娜  周志超  董建楠  张明  刘淑芬 《地质学报》2016,90(2):376-382

高放废物地质处置是将高放废物与人类环境安全隔离的有效途径。高放废物处置库的围岩通常为低渗透的岩体,其安全性在很大程度上取决于围岩对核废物的屏障功能和作为核素迁移载体的裂隙水运动特征。因此,开展处置库场址水文地质评价工作尤为重要。新疆雅满苏和天湖预选地段是我国高放废物处置库预选地段之一。花岗岩是选定的围岩。在过去的3年里,为了认识该地段地下水的形成机制和更新能力,提供该区处置库场址筛选和评价的依据,在该区开展了区域水文地质调查和地下水样品采集。根据调查结果和样品测试数据,本文主要讨论了该地段地下水同位素特征及其水文地质意义,结果表明,地下水δ~2H值主要分布在10.6‰至-82.5‰之间,平均值-46.1‰;δ~(18)O值主要分布在10.2‰至-9.8‰‰之间,平均值-2.06‰;地下水氚含量在1TU~46.1TU之间。地下水δ~2H和δ~(18)O散点图显示,二者主要落在大气降水线的附近和下方,表明区内地下水主要源自当地现代降水的补给,并经受了强烈的蒸发作用,且深部地下水交替能力明显弱于浅部地下水。这一认识为该区处置库选址和场址评价提供了重要水文地质依据。  相似文献   

地球物理勘探技术在地质处置库选址中的应用     

张华  龚育龄  刘庆成  邓居智 《铀矿地质》2012,(4):244-249

简要介绍了我国高放废物地质处置库选址的发展趋势,说明深部断裂构造、岩体的空间形态以及局部不良地质体是当前处置库选址的主要地质问题,综合论述了高放废物处置库选址中采用的地球物理勘探技术,介绍了重磁勘探、地震勘探、电磁法勘探及地面γ能谱测量等地球物理勘探技术,并且以甘肃北山新场预选区岩体为例,说明地球物理勘探技术解决的主要地质问题以及存在的不足。结果表明,该技术在探测处置库预选区花岗岩深部地质构造特征方面具有明显的优势,为处置库场址的稳定性和完整性评价提供参考。  相似文献   

高放废物处置库北山预选区区域水文地质概念模型     

王海龙  郭永海 《国外铀金地质》2014,(1):27-31,38

地下水流数值模拟是高放废物处置库选址中水文地质评价的重要内容.水文地质概念模型是地下水流数值模拟的基础和前提.在北山预选区水文地质分析基础上,利用DEM数据生成了研究区地表水系,据此确定了模拟范围;借助GMS软件,建立了研究区三维水文地质结构模型;再通过边界条件、流场特征、地下水均衡项和水文地质参数的分析和描述,建立了北山地区水文地质概念模型.  相似文献