Application of an optimum design technique for determining the coefficient of consolidation by using piezocone test data

For normally consolidated clay, several researchers have developed a number of theoretical time factors to determine the coefficient of consolidation from piezocone test results. However, depending on assumptions and analytical techniques, it could vary considerably, even for a specific degree of consolidation. In this paper a method is proposed to determine a consistent coefficient of consolidation by applying the concept of an optimum design technique over all ranges of the degree of consolidation. Initial excess pore pressure distribution is assumed to be capable of being obtained by the successive spherical cavity expansion theory. The dissipation of pore pressure is simulated by means of a two-dimensional linear-uncoupled axi-symmetric consolidation analysis. The minimization of differences between measured and predicted excess pore pressure was carried out by the BFGS unconstrained optimum design algorithm with a one-dimensional golden section search technique. By analyzing numerical examples and in-situ test results, it was found that the adopted optimum design technique gives consistent and convergent results.     

A variance-ratio test for supporting a variable mean in kriging

This article discusses the issue of whether to use a variable mean and describes a test that can be used to evaluate whether it is justified to add terms to the drift (deterministic part) of a geostatistical model. The basic model could be the intrinsic one, where the deterministic part is a constant, and the alternate model could be any model that includes a constant term in the expression for the drift. Also, differences between constant- and variable-mean models are discussed.     

Testing an earthquake prediction algorithm

A test to evaluate earthquake prediction algorithms is being applied to a Russian algorithm known asM8 TheM8 algorithm makes intermediate term predictions for earthquakes to occur in a large circle, based on integral counts of transient seismicity in the circle. In a retroactive prediction for the period January 1, 1985 to July 1, 1991 the algorithm as configured for the forward test would have predicted eight of ten strong earthquakes in the test area. A null hypothesis, based on random assignment of predictions, predicts eight earthquakes in 2.87% of the trials. The forward test began July 1, 1991 and will run through December 31, 1997. As of July 1, 1995, the algorithm had forward predicted five out of nine earthquakes in the test area, which success ratio would have been achieved in 53% of random trials with the null hypothesis.     

计算机多媒体技术在地学领域中的某些应用

结合地质工作特点，概述了计算机多媒体技术在地质科研、地质教育、成果汇报演示以及地质信息管理方面的应用成果，展示了多媒体技术在地学领域中的应用前景。     

对企业信息化建设的认识

本文简要介绍了企业信息化的概念、内容及实现企业信息化的关键技术 ;阐述了企业信息化建设过程中应注意的问题 ,认为应坚持从企业实际出发 ,进行整体规划 ,注意开发和利用并重 ,使信息化适合企业个性化需求。     

后遥感应用技术研究与地质实践——以东胜—神木地区铀资源勘查为例

介绍了后遥感应用技术提出的背景及技术构成,阐述了该技术的研究内容及取得的地质成果。实践表明,在地质勘查领域,后遥感应用技术比单一遥感技术具有更大的实用价值和更好的应用效果。     

地理信息技术的发展与应用

地理信息系统是国家信息资源的重要组成部分。地理信息技术经过20多年的飞速发展，已经渗透到社会各个方面，促使人们生产、生活方式发生深刻变化。我国地理信息系统(GIS)技术正在向信息化方向发展，并正在逐步成为面向21世纪的支柱产业一信息产业的重要组成部分。国际GIS技术的发展趋势，主要体现在两个方面，一是综合，二是分化。从空间信息处理的角度看，可将GIS的发展分为空间信息的管理、分析、模拟和调控四个阶段。GIS技术的应用表现在一是面向大型项目，二是面向公众。     

昆明市东川区泥石流信息系统的建立及其应用

根据东川区泥石流的成因、泥石流灾害信息源、各类数据的表达方式及泥石流信息系统的应用等，对东川区泥石流信息系统进行了系统分析，在此基础上利用3S技术，在ARCVIEW的AVENUE开发语言支持下，集成各类数据，建立东川区泥石流信息系统，最后讨论了该系统在泥石流危险度区划及灾害趋势分析中的应用。     

嘉山地震台地电阻率数字化改造

地球科学是一门观测科学,地震观测是研究与应用的基础。地电阻率作为地震前兆观测手段之一,发挥着日益重要的作用,而良好的观测系统是产出连续、可靠、高质量数据的前提。因此,对观测系统的数字化改造工作必须予以高度重视。本文对嘉山台地电阻率数字化改造工作进行了简要介绍,并就一些技术问题进行了论述。     

Stability and accuracy analysis of the central difference method for real‐time substructure testing

The central difference method (CDM) that is explicit for pseudo‐dynamic testing is also believed to be explicit for real‐time substructure testing (RST). However, to obtain the correct velocity dependent restoring force of the physical substructure being tested, the target velocity is required to be calculated as well as the displacement. The standard CDM provides only explicit target displacement but not explicit target velocity. This paper investigates the required modification of the standard central difference method when applied to RST and analyzes the stability and accuracy of the modified CDM for RST. Copyright © 2005 John Wiley & Sons, Ltd.