丰城洛市地区推,滑覆构造特征及其成因探讨

介绍了洛市地区推、滑覆构造特征、运动学标志及其形成时期、成因模式。     

Seismic Ground Motion Expected for the Eastern District of Naples

The seismic ground motion of a test area in the eastern district of Naples is computed with a hybrid technique based on the mode summation and the finite difference methods. This technique allows us the realistic modelling of source and propagation effects, including local soil conditions. In the modelling, we consider the 1980 Irpinia earthquake, a good example of strong shaking for the area of Naples, which is located about 90 km from the epicenter.The detailed geological setting is reconstructed from a large number of drillings. The sub-soil is mainly formed by alluvial (ash, stratified sand and peat) and pyroclastic materials overlying a pyroclastic rock (yellow neapolitan tuff), representing the neapolitan bedrock. The detailed information available on mechanical properties of the sub-soil and its geometry warrants the application of the sophisticated hybrid technique.As expected, the sedimentary cover causes an increase of the signal's amplitudes and duration. If thin peat layers are present, the amplification effects are reduced, and the peak ground accelerations are similar to those observed for the bedrock model. This can be explained by the backscattering of wave energy at such layers, that tend to seismically decouple the upper from the lower part of the structure.For SH-waves, the influence of the variations of the S-wave velocities on the spectral amplification is studied, by considering locally measured velocities and values determined from near-by down-hole measurements. The comparison between the computed spectral amplifications confirms the key role of an accurate determination of the seismic velocities of the different layers.The comparison performed between a realistic 2-D seismic response and a standard 1-D response, based on the vertical propagation of waves in a plane layered structure, shows considerable difference, from which it is evident that serious caution must be taken in the modelling of expected ground motion at a specific site.     

端头扩大型土层锚杆技术

锚固力是土锚重要的工作性指标，端头扩大型土层锚杆技术作为提高锚固力的一种有效手段虎来越得到人们的重视，为此，在这着重介绍国内外土层锚杆端头扩大技术的原理及应用发展情况。     

Separate Analysis of Remote Sensing Information of Structures of Different Geological Periods and Quantitative Study of Corresponding Tectonic Stress Fields

The structural feature shown on a remote sensing image is a synthetic result ofcombination of the deformations produced during the entire geological history of an area.Therefore, the respective tectonic stress field of each of the different stages in the complexdeformation of an area can be reconstructed in three steps: (1) geological structures formed atdifferent times are distinguished in remote sensing image interpretation; (2) structuraldeformation fields at different stages are determined by analyzing relationships betweenmicrostructures (joints and fractures) and the related structures (folds and faults); and (3)tectonic stress fields at different stages are respectively recovered through a study of the featuresof structural deformation fields in different periods. Circular structures and related circlular and radial joints are correlated in space to con-cealed structural rises. The authors propose a new method for establishing a natural model ofthe concealed structural rises and calculating the tectonic stress field by using quantitative dataof the remote sensing information of circular structures and related linear structures.     

青藏高原Pn波研究进展及问题

简要总结了青藏高原地区Pn波速度结构、各向异性研究进展；介绍了Pn波速度结构、各向异性等在岩石圈结构、构造背景反映等方面的应用研究进展。分析了目前青藏高原Pn波研究中存在的一些问题。     

基于复模态的有限元模型修正算法

针对地下结构地震响应分析中无限地基辐射阻尼问题，引入复模态情况下的具有非简化的堆积阻尼矩阵的阻尼模型，并针对具有集中质量阵的阻尼模型提出了合并与质量有关的阻尼和堆积阻尼的思想，并据此提出了一种修正此类有限元模型的两步法，首先从复模态参数中提取实模态参数，采用基于模态残余力的识别算法修正刚度矩阵，然后根据复模态参数和已得的刚度矩阵来识别阻尼模型中的刚度参与系数和质量阻尼堆积阻尼联合矩阵。     

带"人字"支撑的新型复合结构体系动力特征研究

探讨了一种新型复合结构——带“人字”支撑的梁柱体系的动力特征问题。在满足静力荷载作用下承载力要求的基础上，根据结构动力学原理，推导了该结构体系的动力特征方程，分析了复合结构体系的支撑截面和型式的变化对动力特征的影响，计算显示，增加支撑对提高结构的频率即抗侧刚度有明显作用，且随支撑截面尺寸增大，固有频率单调增加。支撑倾角在一定范围内变化时，对频率影响较大，而超过该范围时，其影响明显减小，由此说明“人字”支撑为较合理的支撑型式。结果表明，所研究的具有“人字”支撑的复合结构体系具有较高的抗侧能力。     

某中学教学楼的抗震鉴定与加固设计

按老规范设计的砌体结构未考虑抗震，使用年代过长会出现承载力不足的问题，需对原结构按新规范进行全面检测和抗震鉴定，若鉴定结果表明该结构不符合抗震要求，则需进行加固，结合一实际工程对检测程序和加固方法做一全面论述，供工程实际中参考。