Large scale buffer material test: Mock-up experiment at CIEMAT     

P.L. Martín  J.M. Barcala 《Engineering Geology》2005,81(3):298-316

FEBEX is a demonstration and research project, which is being carried out by an international consortium led by the Spanish agency ENRESA and simulates components of the engineering barrier system in accordance with the ENRESA's AGP (Deep Geological Disposal) Granite reference disposal concept. The project includes tests on three scales: an “in situ” test at full scale in natural conditions; a “mock-up” test at almost full scale in controlled conditions; and a series of laboratory test to complement the information from the two large-scale test.The components of the mock-up test are similar to those of the “in situ” test: two electric heaters, a clay barrier consisting of highly compacted bentonite blocks, instrumentation, automatic control of heaters, and a data acquisition system for the data generated. The heterogeneities of the natural system (granite formation) are avoided, the hydration process is controlled with unlimited amount of water at constant pressure, and the boundary conditions are better defined than in the “in situ” test.The operational phase -hydration and heating- started in February 1997. It was initially planned to last for three years, but it has been decided to extend the operational phase to get as close as possible complete saturation of the buffer.Fifty-five months after the start of the operational phase, it can be concluded that the synergy achieved from the simultaneous, integrated performance of tests at different scales, is a valuable approach to establishing the viability of the reference concept, and making progress in the understanding and evaluation of the behaviour in the near field, especially the clay barrier.  相似文献   

Study of desaturation and resaturation in brittle rock with anisotropic damage   总被引：1，自引：0，他引：1  

J.F. Shao  N. Ata 《Engineering Geology》2005,81(3):341-352

This paper deals with numerical modelling of anisotropic damage induced by desaturation and resaturation processes in a brittle rock. This study is conducted in the framework of geological barrier safety analysis for deep disposal of nuclear waste. A non-linear poroelastic model coupled with anisotropic damage is proposed for constitutive modelling of unsaturated rock. A fully coupled FEM method is used for modelling of hydromechanical coupling problems. Instantaneous phase change without dissipation between water liquid phase and vapour is included. Parametric studies are performed to investigate influences of main factors involved in such processes. Rock damage induced by excavation, desaturation and resaturation is evaluated. Finally, we analyse the importance of taking into account the correlation between induced damage and rock permeability.  相似文献   

Response of a double‐wedge base‐isolation device     

J. Enrique Luco 《地震工程与结构动力学》2004,33(13):1271-1286

A novel base‐isolation device is described and its performance is compared with that of a friction pendulum bearing. In its simplest form, the device consists of two wedges sliding on a horizontal plane in opposite directions and constrained from retreating by ratchets or bilinear dampers. The superstructure rests at the intersection of the two wedges. For a sufficiently large horizontal acceleration of the base, the structure starts to move up the inclined plane of one of the wedges, which remains fixed while the second wedge is slaved to follow the structure. As the direction of the base acceleration reverses, the process is reversed and the structure starts to climb on the second inclined plane while the first wedge follows. The overall result is that the horizontal acceleration of the structure is reduced with respect to that of the base and that kinetic energy associated with horizontal velocities is systematically transformed into potential energy. In the case of motion in a vertical plane, the device has the following advantages over a friction pendulum: (i) the sliding surface is linear instead of curved, (ii) kinetic energy is systematically transformed into potential energy during the strong ground motion, and (iii) the device is slowly self‐centering. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

高放射性废物深地质处置库预选场址深部花岗岩的同位素地球化学     

罗兴章  闵茂中  郑正  王驹  金远新  郭永海 《地质学报》2004,78(5):689-698

评价高放射性废物深地质处置库安全性能的一个重要方面是研究处置库的远场地球化学环境 ;矿物和岩石同位素地球化学研究可以较客观地重现矿物、岩石形成时的古环境及其演化历史。对中国第一个高放射性废物处置库预选场深部花岗岩不同深度裂隙充填矿物 (方解石、石英 )的 C、O同位素 ,Rb- Sr同位素及铀系核素的研究表明预选场深部花岗岩可分为四种不同的地球化学环境 :1浅部 (0～ 15 0 m ) ,其填隙矿物的δ1 8O(SMOW) =12 .1‰～ 13.0‰ ,δ1 3C(PDB) =- 9.5‰～ - 10 .1‰ ,δ87Sr=- 3.2 4‰～ - 1.0 9‰ ,填隙矿物形成于低温流体环境 ,为大气降水补给。 2中—上部 (15 0～ 35 0 m) ,δ1 8O(SMOW) =13.3‰～ 18.0‰ ,δ87Sr≈ 0 ,δ1 3C(PDB) =- 11.2‰～- 10 .5‰ ,填隙矿物形成时其流体来源较复杂 ,为大气降水和盆地卤水的混合流体 ,且处于弱还原环境 ;铀系核素活度数据也显示此区段地下水环境相对稳定 ,未受到现代大气降水或地下水的影响。 3中—下部花岗岩 (35 0～5 5 0 m) ,填隙矿物形成时的环境由两种不同性质的地下水控制 ,但深部地球化学环境相对稳定。 4深部 (>5 5 0 m) ,岩性相对稳定 ,地下水—花岗岩的反应处于稳定的长期平衡状态。这种地球化学环境对于高放射性废物的永久处置是有利的。  相似文献   

基于CBR勘探平巷掘进范例库的研究与开发     

王树理王成虎  郑秀华吕科验 《华东地质学院学报》2004,27(3):220-224

CBR方法是近年来人工智能领域非常先进和实用的方法，在众多领域中都获得了巨大的成功，为了充分实现勘探平巷掘进施工技术中的人工智能思想，笔者基于CBR方法开发了勘探平巷掘进施工范例库。文章介绍了基于范例推理思想及其设计方法，结合勘探平巷掘进施工技术……工程实例利用CBR的基本原理做成范例库，同时介绍了如何进行范例的搜索、改写与复用以及机器学习等问题。通过该范例库的建立，进一步开发了勘探平巷掘进设计过程中的智能化功能。  相似文献   

似大地水准面确定的B样条拟合     

田晋  暴景阳  刘雁春 《测绘信息与工程》2004,29(5):41-43

通过对比目前常用的似大地水准面函数拟合法,提出了B样条曲面拟合原理,运用矩阵论有关方法对其进行解算,模拟算例表明其在拟合精度及等高线局部表现能力上均优于传统方法.  相似文献   

基于GASA混合策略的BP网络在基准地价测算中的应用   总被引：1，自引：0，他引：1  

赖红松  董品杰  祝国瑞 《武汉大学学报(信息科学版)》2004,29(1):24-28

结合遗传算法的并行搜索结构和模拟退火的概率突跳特性 ,提出了一种用于BP网络权值学习的GASA混合策略。以江西省赣县县城商业用地为例 ,应用基于GASA混合策略的BP网络对其基准地价进行了测算 ,并与回归模型方法作了比较。结果表明 ,混合策略能有效地避免BP算法陷入局部极小和网络单目标学习易产生的过拟合现象。将神经网络用于基准地价的测算 ,精度优于常规的回归模型方法。  相似文献   

Kriging空间分析法及其在地价评估中的应用   总被引：13，自引：0，他引：13  

刘耀林  傅佩红 《武汉大学学报(信息科学版)》2004,29(6):471-474

介绍了Kriging空间分析法在地价评估中的应用，并以武汉市住宅地价评估为例，证明了该方法的可靠性。  相似文献   

国土业务建模中的业务规则研究     

周炎坤 《国土资源信息化》2005,(4):43-44,16

在国土业务建模中引入业务规则库的概念,有利于业务流转的规范和准确。本文从为什么要研究业务规则库、规则库的内涵、如何建立完善的规则库三方面进行了探讨,目的是促进国土资源电子政务更加合理地建设和应用。  相似文献   

Online test using displacement–force mixed control     

Peng Pan  Masayoshi Nakashima  Hiroshi Tomofuji 《地震工程与结构动力学》2005,34(8):869-888

This paper proposes an online test technique that employs mixed control of displacement and force. Two types of mixed control, ‘displacement–force combined control’ and ‘displacement–force switching control’ are proposed. In displacement–force combined control, one jack is operated by displacement‐control, and another is operated by force‐control. Validity of the combined control technique is demonstrated by a series of online tests applied to a base‐isolated structure subjected to horizontal and vertical ground motions simultaneously. The substructuring technique is employed in the tests, and the base‐isolation layer is tested, with the rest of the structure modeled in the computer. Displacement‐control and force‐control were adopted for simulating the horizontal and vertical response, respectively. Both displacement‐ and force‐control were implemented successfully despite interference between the two jacks. Earthquake responses of the base‐isolated structure involving the effects of varying axial forces on the horizontal hysteretic behavior of the base‐isolation layer were simulated. In the displacement–force switching control, the jack was operated by displacement‐control when the test specimen was flexible but switched to force‐control once the specimen became stiff. Validity of the switching control technique was also checked by a series of online tests applied to the base‐isolated structure subjected to vertical ground motions. Switching between displacement‐control and force‐control was achieved when the axial force applied to the base‐isolation layer changed from tension to compression or from compression to tension. Both the displacement‐ and force‐control were successful even with many rounds of switching. The test revealed that large accelerations occurred on the floor immediately above the base‐isolation layer at the instants when the axial force of the base‐isolation layer changed from tension to compression. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献