The three faces of geological computer contouring

Three aspects of successful contouring with the computer are geologic interpretation, data, and the program or algorithm. All of these are important and must be considered jointly to combine good procedures with appropriate software, but interpretation is a critical requirement for mapping geologic variables. Several acceptable, though different, maps could be drawn with a given program and set of observations, so the map that best honors geologic concepts and interpretation is most desirable. Many computer-mapping projects are flawed because one of these three aspects is ignored.This paper points out how data handling and choice of an algorithm should be affected by geologic knowledge and interpretation, including: (a) data consisting of mixtures of populations should be handled with special methods, (b) the algorithm should allow calculation of values beyond the range of observed values, (c) mapping thickness of a unit that pinches out requires projection to negative values and special handling of zero-thickness data, and (d) mapping structure on two related horizons requires that the surfaces be dealt with jointly.     

闽北地质灾害的分布特征及其成因分析

通过分析闽北地质灾害与降水特征表明:闽北地质灾害时间分布与降水、尤其是与暴雨的分布一致。其空间分布与地质条件的分布一致,而与年降雨量、3~8月降雨量的分布相反。地质灾害发生数的74.9%均在针叶林及经济林中,95.7%发生在坡度>20°的陡坡处。地质灾害与岩土性质以及岩土结构有一定的关系。当浮土厚度在5m或以上时极易发生地质灾害。因此,闽北地质灾害的发生的主要因素是地质条件,强降雨则是其重要的触发条件,人类活动也是诱发地质灾害的因素之一。文章根据地质条件将闽北的地质灾害按易发程度分为:高易发区、中易发区及低易发区。     

Computer-composite mapping for geologists

A computer program for overlaying maps has been tested and evaluated as a means for producing geologic derivative maps. Four maps of the Sugar House Quadrangle, Utah, were combined, using the Multi-Scale Data Analysis and Mapping Program, in a single composite map that shows the relative stability of the land surface during earthquakes. Computer-composite mapping can provide geologists with a powerful analytical tool and a flexible graphic display technique. Digitized map units can be shown singly, grouped with different units from the same map, or combined with units from other source maps to produce composite maps. The mapping program permits the user to assign various values to the map units and to specify symbology for the final map. Because of its flexible storage, easy manipulation, and capabilities of graphic output, the composite-mapping technique can readily be applied to mapping projects in sedimentary and crystalline terranes, as well as to maps showing mineral resource potential.     

地质图形处理系统设计

介绍了地质图形计算机处理系统的系统功能、系统结构、图形数据库结构以及图形生成与编辑;讨论了在开发地质图形计算机辅助设计或绘图系统时,应如何体现专业特点,如何在数据中表达地质现象的地层和构造意义,如何在地质模型建立中融入专业人员的地质背景知识,以及怎样设计出实际有效的地质图形处理软件系统等问题。      

An empirical coverage test for the g -sample problem

A nonparametricg-sample empirical coverage test has recently been developed for univariate continuous data. It is based upon the empirical coverages which are spacings of multiple random samples. The test is capable of detecting any distributional differences which may exist among the parent populations, without additional assumptions beyond randomness and continuity. The test can be effective with the limited and/or unequal sample sizes most often encountered in geologic studies. A computer program for implementing this procedure, G-SECT 1, is available.     

金伯利岩型金刚石找矿准则和找矿判别模型

本文在深入研究金伯利岩型金刚石矿床成矿规律的基础上,总结了此类矿床的找矿准则并建立了找矿判别模型。模型共包含16个变量,其中地质因素3个,特征矿物5个,岩石化学8个。模型临界值为24.1—65.5。得分大于65.5的岩体为寻找金刚石的重要对象;得分小于24.1的岩体据目前认识水平为不含金刚石岩体;介于两者之间者为可疑岩体。此判别模型综合吸收了前人寻找此类矿床的经验,并将其抽象为定量预测。我们已将此方法用 BASIC 语言编成计算机程序,这将有助于在较大范围内,较迅速、较准确地寻找金刚石矿床。     

An empirical coverage test for theg-sample problem

A nonparametricg-sample empirical coverage test has recently been developed for univariate continuous data. It is based upon the empirical coverages which are spacings of multiple random samples. The test is capable of detecting any distributional differences which may exist among the parent populations, without additional assumptions beyond randomness and continuity. The test can be effective with the limited and/or unequal sample sizes most often encountered in geologic studies. A computer program for implementing this procedure, G-SECT 1, is available.     

长春-吉林输油管道工程建设用地地质灾害危险性分析

长春—吉林输油管道敷设区地质环境条件复杂性为中等复杂,现状地质灾害种类有崩塌、不稳定斜坡和水土流失,主要分布在低山丘陵区,规模均属小型。地质灾害危险性小,无可能引发或加剧的地质灾害。可能遭受的地质灾害主要为由于地震或断裂构造引起的地层错动或不均匀地面沉降,导致管线开裂。     

地质图机助制图相关的几个问题

对地质图机助制图过程中地质信息数据库的建立、地质要素数字化、制图综合自动化、地质符号计算机管理４个方面作了详细论述。并重点提出了区调图幅数字化时的图层划分方案。     

边坡岩体结构的三维失稳形式及稳定性分析研究

由两组结构面控制的四面体块体是岩体中最基本的结构体, 其稳定性取决于块体所受荷载及结构面上的摩阻力。正确判定边界面上摩阻力分布是评价块体稳定性的关键。本文提出的块体稳定性分析适用于岩体所受荷载为三维非共点力系。在不同外力作用下块体可产生平动、转动、翘扭及倾倒等各种三维失稳组合形式, 从而得到更为合理的块体稳定性评价。     

Approximation of a near-vertical boundary in the problems of pulsed electromagnetic soundings

We analyze the results of a mathematical simulation of pulsed electromagnetic fields in geologic media with dipping near-vertical boundaries as well as interpretations within approximating block models and a layered homogeneous conducting model. We consider the possibilities and limitations of these approaches to the inversion of data from pulsed soundings of actual geologic media.     

闽北地区常见几种地质灾害及防治措施

闽北地区广泛分布变质岩、沉积岩和岩浆岩,其岩层风化程度差异较大,诱发滑坡、崩塌、泥石流地质灾害的环境地质条件变化较大,是福建省地质灾害多发区。通过对闽北山区10县、市(区)所发生的地质灾害进行归类统计,总结出该区地质灾害易发的空间地理分布规律,提出防治措施。     

广西某大桥桩基方案三维弹塑性有限元分析

通过三维弹塑性有限元计算程序对处于复杂地质条件中某大桥桩基进行分析,考虑了初始地应力的影响,计算出了承台、桩顶和桩底的位移,以及承台、桩、土及岩石的应力值,并绘出了相应的应力等值线图,对基岩受力后的稳定性给出了评价。     

用空间解析几何法绘制矿脉迹线

利用空间解析几何法展绘地质设计中的中段及剖面地质图上的矿脉的理想迹线,将传统的图解推测矿脉法上升到定量计算推测法,为用计算机绘制地质设计图件打下基础。     

MAIN FEATURES OF PHILOSOPHICAL MATERIALISM IN GEOLOGICAL WORKS OF M. V. LOMONOSOV

This tribute praises Lomonosov for his purported employment of the dialectic concept to the evolution of the earth. The claim that Lomonosov's interpretations of the earth are materialistic is absolutely true, as are all other scientific interpretations. Whether he is the father of materialism in Russian science is of little importance because all sound science is materialistic.

Twelve partly substantiated claims about Lomonosov's work are summarized. The statements that he first applied historical analysis to explain geologic phenomena and that he established the principle of actualism 70 years before LyeII should be brought to the attention of those unfamiliar with the contributions of the great Russian scientist. The tribute contains a good bibliography.--B. N. Cooper.     

东安金矿开采技术条件

东安金矿区地下水以构造裂隙水为主,未来开采矿坑涌水量不大;矿体及围岩坚硬稳固,工程地质条件简单;区域地块稳定,地貌地质条件不易引发地质灾害,也无其它不良环境地质现象,矿床开采技术条件为简单型。     

岩体结构稳定性的块体力学分析

引言 岩石块体的稳定分析在岩体工程地质力学研究中已经逐渐形成一个重要的课题,很多文献在这方面进行了探讨。 在岩石块体的稳定分析时,由于多组结构面的约束,往往遇到超静定问题而不好解决。即使是四面体这样一种岩体中最基本的结构体,它的稳定分析也很不完善。迄今为止,大部分文献都把块体的初始受力当作共点力系来研究。     

MathCAD在地质模拟的数据分析和处理中的应用

地质模拟正从一维、二维技术向三维技术发展,需要分析和处理的数据成倍甚至上百倍增长.随着计算机技术的快速发展,数据分析和处理的速度也随之快速增长,但运用常规的编程来分析和处理这些数据费时又费力.而MathCAD具有解决这一问题的强大的数据分析、处理功能和仿真功能,将MathCAD应用于地质模拟的数据分析和处理中是十分必要的和可行的.本文简要介绍了MathCAD的功能和其在各类地质模拟的数据分析和处理中的应用.     

Environmental benefits vs. costs of geologic mapping

Boone and Winnebago Counties, Illinois, U.S.A., were selected for this study, required by the Illinois State Senate, because mapping and environmental interpretations were completed there in 1981. Costs of geologic mapping in these counties in 1990 dollars were $290,000. Two estimates of costs of statewide mapping were made, one extrapolated from Boone and Winnebago Counties ($21 million), the other estimated on the basis of differences between the Boone/Winnebago program and proposed mapping program for the State of Illinois ($55 million).Benefits of geologic information come in the form of future avoided costs for environmental cleanup. Only the quantifiable data, available from a few sites, were included.Data collection, based on 55 personal interviews in Boone and Winnebago Counties, were grouped into four cumulative categories with increasing variability. Geologic maps alone cannot account for all avoided costs of future cleanup. Therefore, estimated benefits were reduced by 50, 75, and 90 percent in three scenarios. To account for delays in proper utilization of knowledge gained from a mapping program, a 10-yr delay in benefit realization was assumed. All benefits were converted to 1990 dollars.In benefit category 4, benefit-cost ratios for Boone/Winnebago Counties ranged between 5 and 55. Statewide projection of benefits was based on county areas and an aquifer contamination potential score for each county. Statewide benefit-cost ratio in benefit category 4 ranged from 1.2 to 14 ($21 million mapping costs) and from 0.5 to 5.4 ($55 million mapping costs).     

岩体结构稳定分析原理和方法

工程实践表明,在边坡、地基或地下工程岩体中几组地质结构面和临空面的组合往往构成可能失稳的岩石结构体、存在向临空面运动的可能性、影响到工程岩体的稳定性。这时必须针对这种可能失稳的结构体进行分析,采取必要的加固或处理。关于岩石结构体的稳定分析,文献中已有一些报导,但偏重于图解和计算方法、一般是针对特定单一块体的解析,仅应用于边坡工程。