高放废物地质处置库选址中的水文地质调查

本文根据国内外研究经验,讨论了高放废物地质处置库选址中水文地质调查的目的、过程、方法和作用,同时对水文地质参数的获取进行了阐述,旨在为今后研究工作提供参考。     

高放废物处置库预选场地地学信息库的建立

本文以高放废物处置库预选场地甘肃北山玉门镇地学信息库的建立为例,详细阐述了地理信息系统在高放废物地质处置中的应用,并在此基础上分析了其应用前景,为不同层次的管理、科研人员提供了全新思路;介绍了将地理信息系统技术引入图件和资料管理的优点。     

高放废物处置库甘肃北山预选区地下水位动态特征

阐明了甘肃北山预选区地下水位动态特征及其与当地大气降水的关系,并对其动态类型进行了剖析,由此得出北山地区地下水源自当地大气降水补给的认识。为处置库预选区场址评价提供了水文地质依据。     

冰雪灾害条件下地质灾害应急抢险处置知识构成分析

知识库是冰雪灾害条件下地质灾害应急抢险决策支持系统的核心,知识库中的知识构成则是整个研究的基础。本文按照产生式规则法的知识表示方式,分别分析了冰雪灾害条件下地质灾害应急抢险处置知识的前提及结论部分的主要构成内容,并总结了应急抢险处置措施选择应该遵循的基本原则,另外还给出了根据知识构成抽取具体知识的范例,为冰雪灾害条件下地质灾害应急抢险知识库及决策支持系统的建立提供了基础性研究成果。     

Early Estimation of Seismic Hazard for Strong Earthquakes in Taiwan

A shakemap system providing rapid estimates of strong ground shaking could be useful for emergency response providers in a damaging earthquake. A hybrid procedure, which combines site-dependent ground motion prediction models and the limited observations of the Real-Time Digital stream output system (RTD system operated by Central Weather Bureau, CWB), was set up to provide a high-resolution shakemap in a near-real-time manner after damaging earthquakes in Taiwan. One of the main factors that affect the result of ground motion prediction analysis is the existence of site effects. The purpose of this paper is to investigate the local site effects and their influence in the ground shaking and then establish an early estimation procedure of potential hazard for damaging earthquakes. Based on the attenuation law, the site effects of each TSMIP station are discussed in terms of a bias function that is site and intensity-level dependent function. The standard deviation of the site-dependent ground motion prediction model can be significantly reduced. The nonlinear behavior of ground soil is automatically taken into account in the intensity-level dependent bias function. Both the PGA and the spectral acceleration are studied in this study. Based on the RTD data, event correctors are calculated and applied to precisely estimate the shakemap of damaging earthquakes for emergency response.     

An elastoviscoplastic constitutive model for geomaterials: Application to hydromechanical modelling of claystone response to drift excavation

An isotropic elastoviscoplastic constitutive model based on a generalized Hoek-Brown criterion is proposed. The plastic mechanism is characterized by a positive and a negative hardening, and a specific non-associated flow rule allows to take into account the evolution of the dilatancy. Several hydromechanical finite element simulations corresponding to realistic configurations of drift excavations in the underground research laboratory of Bure are presented. Regularization techniques are required to avoid localization phenomena due to softening. A second gradient formulation has been used as it is well suited for dilatant materials such as claystone. Numerical results are discussed and compared with experimental measurements.     

Stability at high-pressure,elastic behaviour and pressure-induced structural evolution of CsAlSi<Subscript>5</Subscript>O<Subscript>12</Subscript>, a potential host for nuclear waste

The elastic and structural behaviour of the synthetic zeolite CsAlSi₅O₁₂ (a = 16.753(4), b = 13.797(3) and c = 5.0235(17) Å, space group Ama2, Z = 2) were investigated up to 8.5 GPa by in situ single-crystal X-ray diffraction with a diamond anvil cell under hydrostatic conditions. No phase-transition occurs within the P-range investigated. Fitting the volume data with a third-order Birch–Murnaghan equation-of-state gives: V ₀ = 1,155(4) ų, K _T0 = 20(1) GPa and K′ = 6.5(7). The “axial moduli” were calculated with a third-order “linearized” BM-EoS, substituting the cube of the individual lattice parameter (a ³, b ³, c ³) for the volume. The refined axial-EoS parameters are: a ₀ = 16.701(44) Å, K _T0a = 14(2) GPa (β_a = 0.024(3) GPa^?1), K′ _a = 6.2(8) for the a-axis; b ₀ = 13.778(20) Å, K _T0b = 21(3) GPa (β_b = 0.016(2) GPa^?1), K′ _b = 10(2) for the b-axis; c ₀ = 5.018(7) Å, K _T0c = 33(3) GPa (β_c = 0.010(1) GPa^?1), K′ _c = 3.2(8) for the c-axis (K _T0a:K _T0b:K _T0c = 1:1.50:2.36). The HP-crystal structure evolution was studied on the basis of several structural refinements at different pressures: 0.0001 GPa (with crystal in DAC without any pressure medium), 1.58(3), 1.75(4), 1.94(6), 3.25(4), 4.69(5), 7.36(6), 8.45(5) and 0.0001 GPa (after decompression). The main deformation mechanisms at high-pressure are basically driven by tetrahedral tilting, the tetrahedra behaving as rigid-units. A change in the compressional mechanisms was observed at P ≤ 2 GPa. The P-induced structural rearrangement up to 8.5 GPa is completely reversible. The high thermo-elastic stability of CsAlSi₅O_12, the immobility of Cs at HT/HP-conditions, the preservation of crystallinity at least up to 8.5 GPa and 1,000°C in elastic regime and the extremely low leaching rate of Cs from CsAlSi₅O₁₂ allow to consider this open-framework silicate as functional material potentially usable for fixation and deposition of Cs radioisotopes.