多源卫星遥感的湖南矿山违法开采时空变化

近年来不合理的开发利用矿产资源一直是备受关注的问题,对违法开采矿产资源的时空分布特征研究显得尤为重要.为解决大范围矿产资源违法开采信息获取难、精度低,数据零散、缺乏长时序的问题,本文提出了基于多源卫星遥感数据与克立金数据分析相结合的矿山违法开采时空分布特征研究方法.首先以湖南省为研究区域,采用2010年—2017年多时...     

A probabilistic framework for quantification of aftershock ground‐motion hazard in California: Methodology and parametric study

This paper presents a proposed method of aftershock probabilistic seismic hazard analysis (APSHA) similar to conventional ‘mainshock’ PSHA in that it estimates the likelihoods of ground motion intensity (in terms of peak ground accelerations, spectral accelerations or other ground motion intensity measures) due to aftershocks following a mainshock occurrence. This proposed methodology differs from the conventional mainshock PSHA in that mainshock occurrence rates remain constant for a conventional (homogeneous Poisson) earthquake occurrence model, whereas aftershock occurrence rates decrease with increased elapsed time from the initial occurrence of the mainshock. In addition, the aftershock ground motion hazard at a site depends on the magnitude and location of the causative mainshock, and the location of aftershocks is limited to an aftershock zone, which is also dependent on the location and magnitude of the initial mainshock. APSHA is useful for post‐earthquake safety evaluation where there is a need to quantify the rates of occurrence of ground motions caused by aftershocks following the initial rupture. This knowledge will permit, for example, more informed decisions to be made for building tagging and entry of damaged buildings for rescue, repair or normal occupancy. Copyright © 2008 John Wiley & Sons, Ltd.     

Coupled shear‐bending formulation for seismic analysis of stacked wood shear wall systems

A summary of the development of a new coupled shear‐bending model for analysis of stacked wood shear walls and multi‐story wood‐frame buildings is presented in this paper. The model focuses on dynamic response of light‐frame wood structures under seismic excitation. The formulation is intended to provide a more versatile option than present pure shear models in that the new model is capable of accurately capturing the overall lateral response of each story diaphragm and separates the inter‐story shear deformation and the deformation associated with rotation of the diaphragm due to rod elongation, which is an analogue to the bending deformation in an Euler–Bernoulli beam model. Modeling the coupling of bending and shear deformation is shown to provide more accurate representation of stacked shear wall system behavior than a pure shear model, particularly for the upper stories in the assembly. The formulation is coupled with the newly developed evolutionary parameter hysteretic model for wood shear walls. Existing data from a shake table test of an isolated three‐story wood shear wall were used to verify the accuracy of the model prediction. The numerical results agreed very well with shake table test measurements. The influence of a continuous rod hold‐down system on the dynamic behavior of the three‐story stacked wood shear wall was also successfully simulated. Copyright © 2009 John Wiley & Sons, Ltd.     

A substructure shaking table test for reproduction of earthquake responses of high‐rise buildings

When subjected to long‐period ground motions, high‐rise buildings' upper floors undergo large responses. Furniture and nonstructural components are susceptible to significant damage in such events. This paper proposes a full‐scale substructure shaking table test to reproduce large floor responses of high‐rise buildings. The response at the top floor of a virtual 30‐story building model subjected to a synthesized long‐period ground motion is taken as a target wave for reproduction. Since a shaking table has difficulties in directly reproducing such large responses due to various capacity limitations, a rubber‐and‐mass system is proposed to amplify the table motion. To achieve an accurate reproduction of the floor responses, a control algorithm called the open‐loop inverse dynamics compensation via simulation (IDCS) algorithm is used to generate a special input wave for the shaking table. To implement the IDCS algorithm, the model matching method and the H_∞ method are adopted to construct the controller. A numerical example is presented to illustrate the open‐loop IDCS algorithm and compare the performance of different methods of controller design. A series of full‐scale substructure shaking table tests are conducted in E‐Defense to verify the effectiveness of the proposed method and examine the seismic behavior of furniture. The test results demonstrate that the rubber‐and‐mass system is capable of amplifying the table motion by a factor of about 3.5 for the maximum velocity and displacement, and the substructure shaking table test can reproduce the large floor responses for a few minutes. Copyright © 2009 John Wiley & Sons, Ltd.     

机载激光雷达系统的应用与数据后处理技术

综述了机载激光雷达系统的组成、工作原理、应用和数据后处理技术,着重介绍机载激光雷达数据中的信息提取的有关算法,这些算法包括DEM、DTM提取、房屋提取与房屋几何模型的3D重建、道路网提取、森林参数的获取等。     

灰关联与人工神经网络在建筑物震害预测中的应用

基于灰关联识别方法,解析了各震害影响因子对多层砖房抗震性能的影响程度;并利用BP人工神经网络非线性模型对震害实例样本进行了训练。结果表明:利用灰关联分析,可得出各因子对多层砖房抗震性能影响程度的大小排序,有利于实际的工程抗震设计;基于BP人工神经网络模型的多层砖房的震害预测结果与震害实例的实际情况比较吻合,其思路和方法可推广于其他不同类型的建筑结构的震害预测。     

唐山高层建筑发展方向的思考

唐山地震至今30年来,唐山市建设了一定数量的高层建筑,包括高层公共建筑、高层住宅。本文对已建的主要高层建筑进行了总结,主要的结构体系为高层住宅以钢筋混凝土抗震墙结构为主,高层公共建筑以钢筋混凝土框架抗震墙为主;并分析了高层建筑形式、基础类型等方面的特点。结合建筑理论和技术的发展主要针对结构设计方面提出了唐山市高层建筑建设方面的思考与建议。     

基于BP神经网络模型的多层砖房震害预测方法

针对传统的基于地震烈度的建筑物震害预测方法的不足,本文以地震动峰值加速度作为建筑物震害预测的地震动指标,结合几次大地震中多层砖房的震害实例,提出了一种基于BP神经网络模型的建筑物震害预测方法,模型的输入为反映结构抗震性能的各类物理参数,输出为给定地震动峰值加速度下建筑物破坏状态的概率。研究表明:基于BP网络模型的多层砖房的震害预测结果与震害实例的实际情况比较吻合,本文的思路和方法可推广于其他不同类型的建筑结构的震害预测。     

泉州市区桩基应用的类型与特点

通过对泉州市区岩土工程勘察、设计、施工及检测资料统计,总结了泉州市区桩基应用的类型与特点,并结合典型的实例说明桩基类型的选择应在安全的基础上,选择经济和合理的基础类型。     

Passive and active control of three‐dimensional buildings

The majority of the recent research effort on structural control considers two‐dimensional plane structures. However, not all buildings can be modelled as plane structures, thus limiting the capability of the proposed procedures only to regular and symmetrical structures. A new procedure is developed in this paper to analyse three‐dimensional buildings utilizing passive and active control devices. In the building model, the floors are assumed rigid in their own plane resulting in three degrees of freedom at each floor. Two types of active control devices utilizing an active tuned mass damper and an active bracing system are considered. The effect of passive mass dampers and active control force in the equations of motion is incorporated by using the Hamilton's principle. The passive parameters of the dampers as well as the controller gain is then optimized using a genetic based optimizer where the H₂, H_∞ and L₁ norms are taken as the objective functions. Copyright © 2000 John Wiley & Sons, Ltd.