Petrology of two diamondiferous eclogite xenoliths from the Lahtojoki kimberlite pipe, eastern Finland

Diamondiferous Group A eclogites constitute a minor portion of the mantle-derived xenoliths in the eastern Finland kimberlites. They have been derived from the depth interval 150–230 km where they are inferred to occur as thin layers or small pods within coarse-grained garnet peridotites. The chemical and isotopic composition of minerals suggest that they represent (Proterozoic?) mantle-derived melts or cumulates rather than subducted oceanic lithosphere. During magma ascent and emplacement of the kimberlites, the eclogite xenoliths were mechanically and chemically rounded judging from the types of surface markings. In addition, those octahedral crystal faces of diamonds that were partially exposed from the rounded eclogite xenolith became covered by trigons and overlain by microlamination due to their reaction with the kimberlite magma. The diamonds bear evidence of pervasive plastic deformation which is not, however, evident in the eclogite host. This suggests that annealing at ambient lithospheric temperatures has effectively recrystallised the silicates while the diamond has retained its lattice imperfections and thus still has the potential to yield information about ancient mantle deformation. One of our samples is estimated to contain approximately 90,000 ct/ton diamond implying that some diamonds occur within very high-grade pods or thin seams in the lithospheric mantle. To our knowledge, this is one of the most diamondiferous samples described.     

数字化形变资料分析处理流程

根据形变数字化数据和前兆特征。主要对EIS000中提供的数据处理及异常判定方法进行了使用分析。针对固体潮成分和非固体潮成分。提出了在日常分析和会商中较为适用的方法和步骤。     

液化场地桩-土-桥梁结构动力相互作用振动台试验研究进展

本文在全面归纳与总结液化场地桩－土－桥梁结构动力相互作用振动台试验及与之相关领域的国内外研究进展基础上，直接针对我国桥梁工程中的主要震害问题，提出在我国开展液化场地桩－土－桥梁结构动力相互作用振动台试验研究的必要性，并阐述作者对液化场地桩－土－张桥梁结构动力相互作用振动台试验中若干问题的认识。     

Nonlinear earthquake response analysis and energy calculation for seismic slit shear wall structures

Based on the concept of structural passive control, a new type of slit shear wall, with improved seismic performance when compared to an ordinary solid shear wall, was proposed by the authors in 1996. The idea has been verified by a series of pseudo-static and dynamic tests. In this paper a macro numerical model is developed for the wall element and the energy dissipation device. Then, nonlinear time history analysis is carried out for a 10-story slit shear wall model tested on a shaking table. Furthermore, the seismic input energy and the individual energy dissipated by the components are calculated by a method based on Newmark-β assumptions for this shear wall model, and the advantages of this shear wall are further demonstrated by the calculation results from the viewpoint of energy. Finally, according to the seismic damage criterion on the basis of plastic accumulative energy and maximum response, the optimal analysis is carried out to select design parameters for the energy dissipation device.     

The Advances and Prospects of Research on Earthquake Engineering at IEM

This paper describes briefly the recent advances and acievements of the research projects conducted by the Institute of Engineering Mechanics(IEM) in the period of the Ninth Five-Year Plan(1995-2000) with the support of the China Seismological Bureau(CSB),These projects are related with key problems in the field of earthquake engineering.They are:development of the methods for determining earthquake resistant design load level,study on mechanisms of earthquake damage to buildings.development of new technology of base isolation,and study on earthquake damage prediction and seismic losss assessment methods.Through these studies,quite a number of problems have een solved and some of them have een applied in earthquake engineering design and practice.     

滇西北石鼓片岩变质变形特征及其划分

滇西北金沙江结合带东侧的石鼓变质岩系，可划分为石鼓岩群和巨甸岩群。石鼓岩群受区域动力热流变质作用改造，主期变形环境为中、深部构造相；巨甸岩群受区域低温动力变质作用改造，与之相伴的构造形迹属中、浅部构造相。石鼓岩群包含羊坡岩组和露西岩组，巨甸岩群可进一步划分为陇巴岩组和塔城岩组。同一岩群的岩组，变质作用、构造变形特征相同，但变质岩石组合及原岩特征却有明显差别。     

基于应变模态法识别刚架桥梁的损伤

基于应变模态方法，对刚架桥的损伤识别进行了研究。通过对某刚架桥在不同损伤工况下的数值仿真计算，探讨了应变模态方法用于刚架桥损伤识别的能力。计算结果表明：利用应变模态差曲线能比较准确地识别出刚架桥的损伤位置；应变模态差曲线在刚架桥损伤单元处的跳跃幅值随单元损伤程度的增加而增大，依此可定性地识别出刚架桥的损伤程度。     

高密度电法勘探在岩溶查找中的应用

介绍了武汉市汤逊湖污水处理厂厂址的地质概况和地球物理特征，以及高密度电法勘探的施工方案，分析了视电阻率异常特征，并说明了其异常验证情况。高密度电法勘探结果表明该区存在溶洞，为施工提供了决策依据，建议在有溶洞的地段采取相应措施，以防止工程建设后发生地质灾害。     

A neural network approach for structural identification and diagnosis of a building from seismic response data

This work presents a novel procedure for identifying the dynamic characteristics of a building and diagnosing whether the building has been damaged by earthquakes, using a back‐propagation neural network approach. The dynamic characteristics are directly evaluated from the weighting matrices of the neural network trained by observed acceleration responses and input base excitations. Whether the building is damaged under a large earthquake is assessed by comparing the modal parameters and responses for this large earthquake with those for a small earthquake that has not caused this building any damage. The feasibility of the approach is demonstrated through processing the dynamic responses of a five‐storey steel frame, subjected to different strengths of the Kobe earthquake, in shaking table tests. Copyright © 2002 John Wiley & Sons, Ltd.     

2-D deformation analysis of a half-space due to a long dip-slip fault at finite depth

Closed form analytical expressions of stresses and displacements at any field point due to a very long dip-slip fault of finite width buried in a homogeneous, isotropic elastic half-space, are presented. Airy stress function is used to derive the expressions of stresses and displacements which depend on the dip angle and depth of the upper edge of the fault. The effect of dip angle and depth of the upper edge of the fault on stresses and displacements is studied numerically and the results obtained are presented graphically. Contour maps for stresses and displacements are also presented. The results of Rani and Singh (1992b) and Freund and Barnett (1976) have been reproduced.