海底MT信号采集电路的设计

设计海底大地电磁信号采集电路，需考虑海底信号特征、海上作业以及海底环境等各种因素。分析表明，除遵循电路设计的一般原则外，海底大地电磁测量要重点解决微弱信号检测、智能化数据采集、海底环境监测和同步记录等4个方面的问题。在设计方案中，电路灵敏度达到微伏级；使用嵌入式计算机实现采集控制；对方位、倾斜、振动、温度等参数进行巡回记录；仪器的时钟精度精准到微秒。所研制的电路经过了室内模拟测试和海洋试验。首次采集到中国海域的大地电磁数据。     

Nonlinear Rate Dependent Model of High Damping Rubber Bearing

The accurate analysis of the response of isolated structures requires the application of appropriate models of isolation devices. The purpose of this paper is to analyse a nonlinear strain rate dependent model of a high damping rubber bearing which simulates the horizontal behaviour of the device under specified vertical load using a nonlinear elastic spring-dashpot element. The effectiveness of the model is checked by fitting the experimental data concerning three different rubber bearings. The results of the study show that the model can simulate the bearing behaviour over a wide shear strain range with small simulation errors. This revised version was published online in July 2006 with corrections to the Cover Date.     

Efficiency of base isolation systems in structural seismic protection and energetic assessment

This paper concerns the seismic response of structures isolated at the base by means of High Damping Rubber Bearings (HDRB). The analysis is performed by using a stochastic approach, and a Gaussian zero mean filtered non‐stationary stochastic process is used in order to model the seismic acceleration acting at the base of the structure. More precisely, the generalized Kanai–Tajimi model is adopted to describe the non‐stationary amplitude and frequency characteristics of the seismic motion. The hysteretic differential Bouc–Wen model (BWM) is adopted in order to take into account the non‐linear constitutive behaviour both of the base isolation device and of the structure. Moreover, the stochastic linearization method in the time domain is adopted to estimate the statistical moments of the non‐linear system response in the state space. The non‐linear differential equation of the response covariance matrix is then solved by using an iterative procedure which updates the coefficients of the equivalent linear system at each step and searches for the solution of the response covariance matrix equation. After the system response variance is estimated, a sensitivity analysis is carried out. The final aim of the research is to assess the real capacity of base isolation devices in order to protect the structures from seismic actions, by avoiding a non‐linear response, with associated large plastic displacements and, therefore, by limiting related damage phenomena in structural and non‐structural elements. In order to attain this objective the stochastic response of a non‐linear n‐dof shear‐type base‐isolated building is analysed; the constitutive law both of the structure and of the base devices is described, as previously reported, by adopting the BWM and by using appropriate parameters for this model, able to suitably characterize an ordinary building and the base isolators considered in the study. The protection level offered to the structure by the base isolators is then assessed by evaluating the reduction both of the displacement response and the hysteretic dissipated energy. Copyright © 2003 John Wiley & Sons, Ltd.     

高温高压下含水矿物脱水对斜长岩纵波速度的影响

在1GPa、室温至880℃条件下对斜长岩的纵波速度进行了测量，并对实验产物进行了鉴定分析，讨论了含水矿物脱水对岩石纵波速度的影响。实验结果表明，在680℃左右，由于斜长岩中的含水矿物绢云母和黝帘石开始脱水，矿物脱水产生的流体及其所引起岩石结构的变化可使岩石纵波速度降低10％左右。这意味着通过矿物脱水这一机制可以形成壳内低速层。     

高填方路堤互锚式薄壁挡土墙土压力试验研究

在山区修建高等级公路工程中，挡土墙结构广泛应用于高填方路堤工程。在提出一种新型互锚式薄壁挡土墙结构的基础上，通过埋设土压力盒的方法对该种挡土墙的结构型式进行了力学模型试验，并进行了模型土压力强度特性分析。试验及分析表明，该挡土墙结构成本低廉，施工方便，结构合理，可以应用于高填方路堤实际工程。     

高精度推求正高的两种方法

论述了高精度推求正高的两种方法 ,并对正高精度的推估及其在模型上的试算也作了讨论 ,对于海拔为 5 0 0 0m的高山 ,正高的误差一般不超过± 1 0cm ,这与距青岛水准原点达数千公里的西部高山 (原 )处正常高的精度也比较接近     

珠峰高程测定中的有关问题及思考

对珠峰高程的精度、雪层的厚度、高程基准——大地水准面的精度、地壳的垂直运动以及如何将似大地水准面转换到大地水准面进行了讨论。结果显示，采用正常高加转换公式中的重力或地形资料求取珠峰正高比较合适。     

GPS-OEM在精准农业领域中的应用实例

介绍了我中心开发的内置有GPS—OEM板的农田信息采集系统，指出了GPS—OEM在精准农业领域发展潜力。     

GPS滑坡监测专用的Gquicks软件

介绍了Guicks软件的数学模型,Gquicks软件的结构和功能.经实测检测检验,当基准点与监测点之间距离在3km内,用20分钟GPS观测值,Gquicks软件解算的水平精度可达±2-3mm,垂直精度可达±4-6mm.Gquicks软件不仅适用于GPS滑坡变形监测,也可应用于其他变形监测领域.     

武汉市高层建筑岩土工程问题分析

武汉市是华中地区最大的城市,改革开放以来,兴建了许多高层建筑。高层建筑尤其是超高层建筑的主要特点是高度大、重心高、基底压力大及基础埋深大等。而武汉地区的地质条件又比较复杂,就第四纪地层而言,从最新沉积的各类软土如人工填土、淤泥类土、软塑状粘性土等,到全新世(Q4)沉积的各类砂土与卵砾石,直至晚更新世(Q3)及其以前沉积的老粘土均有分布。各类土层的厚度、深度及性质均变化较大。因此武汉地区高层建筑的岩土工程问题就显得复杂与多样,在众多复杂的岩土工程问题中,本文主要分析了比较突出的基础持力层与基础类型的确定,深基坑开挖中的边坡滑移、基坑涌水、流砂、突涌以及基坑防护等。通过对这些问题的分析,从中可以得出一些规律,对今后高层建筑的兴建具有一定的指导作用。