Experimental remolding on the caprock''s 3D strain field of the Indosinian-Yanshanian epoch in Tongling deposit concentrating area

Based on field observations and rheology analysis, we perform one analogue experiment and remold the 3D structural frame of Tongling deposit concentrating area firstly. Then we disassemble and dialyze the 3D structures of the model using the methods of "slicing" and "stripping". A series of sliced planes vertical to the fold hinges show similar landscapes of that in the drill hole profiles. Meanwhile, layer stripping analysis indicates that the deformation features of each layer in the model are qualitatively analogical to those obtained from field observations.Through contrasting the 3D structure between the experimental model and the field phenomena,we verify the following 3D deformation features of the caprock in this area: (1) the Tongling area mainly consists of three series of NE S-typed fold groups; (2) in the uniform stress field, the incoherent folds universally develop in different positions, along different axes as well as in different strata; (3) the faults propagate upward which are mostly inter-bedded detachment faults,while the fold amplitudes decrease while going deeper; and (4) the folds and cleavages are highly developed in the Silurian System indicating that the deformation effect of the Indosinian-Yanshanian structural layer terminates at this layer, which suggests that the Silurian System is the crucial layer for the inversion between brittle and plastic deformation domains and the underlying strata are subject to the control of another deformation system with distinct properties.     

平面框架结构抗震易损性的简化分析方法

本文采用静力凝聚技术把平面框架结构简化为一维链状结构，从整体性能上估计结构的抗震易损性，引入状态向量，把结构运动微分方程化为状态方程的形式，地震地面加速度被模拟为均值为零的平稳过滤Ｇａｕｓｓ白噪声过程，在时域内导响应相关函数的解析表达式，通过求解协方差反应矩阵方程直接得到系统的均方响应，考虑变形极限状态，采用首次超越失效准则计算不同ＰＧＡ水平下的结构易损性。最后，用一座位于大庆市的九层框架结构的计     

专家系统与智能系统

为使专家系统技术尽早在地学领域取得突破，应该研制智能系统。在人机交换系统中加入智能模块，管理调度各功能模块，即实现人机交互系统到智能系统的升级。将专家系统、骨架系统加以扩充，增加与数据库管理系统、科学计算等功能子系统的接口，即成为一个研制智能系统的工具—智能骨架系统。文末描述了一个智能骨架系统—ＳＧＥＳ的结构和用法     

钢筋混凝土框架结构计算机仿真与并行计算

介绍了钢筋混凝土框架结构计算机仿真和并行计算的研究现状。数值仿真主要采用有限元、离散元等数学物理模型,而可视化技术及图形仿真基于图形学和图像处理技术,是驾驭计算过程及理解大体积数据的唯一有效途径。有限元并行计算有SBS、EBE两种策略,非线性求解有直接与迭代解法,动力时程分析有显式、隐式和精细时程积分法。最后介绍了并行计算在钢筋混凝土结构分析中的应用。     

Seismic performance and new design procedure for chevron‐braced frames

The paper is concerned with the seismic design of steel‐braced frames in which the braces are configured in a chevron pattern. According to EuroCode 8 (EC8), the behaviour factor q, which allows for the trade‐off between the strength and ductility, is set at 2.5 for chevron‐braced frames, while 6.5 is assigned for most ductile steel moment‐resisting frames. Strength deterioration in post‐buckling regime varies with the brace's slenderness, but EC8 adopts a unique q value irrespective of the brace slenderness. The study focuses on reevaluation of the q value adequate for the seismic design of chevron‐braced frames. The present EC8 method for the calculation of brace strength supplies significantly different elastic stiffnesses and actual strengths for different values of brace slenderness. A new method to estimate the strength of a chevron brace pair is proposed, in which the yield strength (for the brace in tension) and the post‐buckling strength (for the brace in compression) are considered. The new method ensures an identical elastic stiffness and a similar strength regardless of the brace slenderness. The advantage of the proposed method over the conventional EC8 method is demonstrated for the capacity of the proposed method to control the maximum inter‐storey drift. The q values adequate for the chevron‐braced frames are examined in reference to the maximum inter‐storey drifts sustained by most ductile moment‐resisting frames. When the proposed method is employed for strength calculation, the q value of 3.5 is found to be reasonable. It is notable that the proposed method does not require larger cross‐sections for the braces compared to the cross‐sections required for the present EC8 method. Copyright © 2005 John Wiley & Sons, Ltd.     

Beamlet prestack depth migration and illumination： A test based on the Marmousi model

Beamlet sources have strong local and directional character and can easily accomplish local illumination and migration. Besides, they provide better migration results than conventional migration methods. We introduce the basic principles of beamlet prestack depth migration that includes a windowed Fourier transform and frame theory. We explain the Gabor-Daubechies （G-D） frame based on a Gaussian function. Beamlet decomposition provides information on the local space and direction of wavefield. We synthesize the beamlet source and beamlet records in the wavelet domain using both rectangle and Gaussian windows and then extrapolate the synthesized data with a Fourier finite-difference operator. We test the method using the standard Marmousi model. By comparing and analyzing the migration results of single directional beamlet and beamlets with different windows and directions, we demonstrate the validity of the prestack depth migration with Gaussian beamlets method.     

外套框架结构改造设计方案的合理选择

外套框架的结构改造设计中，合理地选择正确的方案是保证结构体系安全、经济和良好使用的重要指标。在地震区更为严格地使用正确的设计方案，是解决外套框架加层设计的良好途径。     

GNSS(GPS)观测研究地壳运动的新进展

介绍了近几年来GNSS(GPS)系统、观测技术和数据处理方法和技术的发展,数据格式标准化的进展,全球参考框架现状,参考框架对地壳运动研究的影响和IGS的产品。介绍利用GNSS观测研究地壳运动的成果,包括大地震前后及震时的地壳运动结果,时间序列观测结果的研究进展等。     

Effect of near‐fault ground motion and damper characteristics on the seismic performance of chevron braced steel frames

This study is aimed at comparing the seismic performance of steel chevron braced frames (CBFs) with and without fluid viscous dampers (FVDs) as a function of the characteristics of the near‐fault (NF) ground motion and FVD parameters. For this purpose, comparative nonlinear time history (NLTH) analyses of single and multiple storey CBFs with and without FVDs are conducted using NF ground motions with various velocity pulse periods scaled to have small, moderate and large intensities. Additionally, NLTH analyses of single‐ and four‐storey CBFs with FVDs are conducted to study the effect of the damping ratio and velocity exponent of the FVD on the seismic performance of the frames. The analyses results revealed that the seismic performance of the CBFs without FVDs is very poor and sensitive to the velocity pulse period and the intensity of the NF ground motion due to brace‐buckling effects. Installing FVDs into the CBFs significantly improved their seismic performance by maintaining their elastic behaviour. Furthermore, FVDs with smaller velocity exponents and larger damping ratio are observed to be more effective in improving the seismic performance of the CBFs subjected to NF earthquakes. However, FVDs with damping ratios larger than 50% do not produce significant additional improvement in the seismic performance of the CBFs. Copyright © 2006 John Wiley & Sons, Ltd.