Geology of the New Orleans Area and the Canal Levee Failures

The geologic history of the New Orleans area significantly influences the engineering properties of the foundation soils beneath the levees. Geologic and engineering data gathered from the levee breaches identify a spatially complex geomorphic landscape, caused by Holocene sea level rise, lateral changes in depositional environments, development of Mississippi River delta lobes, and the distributary channels associated with delta development. Overlying the Pleistocene surface beneath New Orleans are predominantly fine-grained, shallow water sediments associated with bay sound (or estuarine), nearshore-gulf, sandy beach, lacustrine, interdistributary, and paludal (marsh and swamp) environments. These environments define the New Orleans area history during the Holocene and comprise the levee foundation beneath the failure areas. A barrier beach ridge is present in the subsurface along the southern shore of Lake Ponchartrain, which blocked the filling of the lake with fluvial-deltaic sediments. This buried beach impacted the supply and texture of sediment being deposited by advancing distributary channels and influenced the engineering properties of these soils. Marsh and swamp soils beneath the failure area at the 17th Street Canal are much thicker in comparison to those beneath the London Avenue Canal failures because of the influence of the beach complex, and are thickest in the Industrial Canal area. Additionally, human activities in the New Orleans area during historic time contributed to the spatial complexity and affected the engineering properties of the foundation soils. These activities include construction of drainage and navigation canals, groundwater pumping, hydraulic filling of the Lake Ponchartrain lake front, and construction of levees to prevent river flooding. Human activities, combined with the geologic setting and subsidence in this region, are responsible for the unique landscape that was impacted by Hurricane Katrina.     

Principles and methodology of design for excavations in geologic media

One of the greatest design endeavours of present time involves a design project to be constructed not in steel or concrete but in geologic media — deep underground in rock — and it will cost over $40 billion when completed around the year 2010. This will be America's first high-level radioactive waste storage repository, currently planned at the Yucca Mountain site in Nevada. Yet at this stage there is no clear design methodology for this project, in spite of some $2 billion having been spent in the past ten years. This paper attempts to answer why this is so and to propose a solution.The paper presents the principles of engineering design and the main stages of the design process methodology developed for excavations in geologic media. From problem formulation, through analysis and synthesis, to evaluation and optimization, the design process is seen as the use of six specific design principles within a systematic but flexible design methodology, leading to innovative problem-solving.     

万家寨引黄工程南干7~#洞膨胀岩洞段工程地质特性

膨胀岩易吸水膨胀、失水崩裂 ,其稳定性差。对隧洞的设计、施工和运行将产生综合性的影响。引黄工程南干 7号隧洞 2 895m长的洞段穿过膨胀岩地层。本文介绍了膨胀岩的特性及对引黄工程的影响。     

SGN气田SC1井～S15井间马四段白云岩化岩性分析

本文根据ＳＧＮ气田的地震资料，结合钻井，地质资料对ＳＣ１井到Ｓ１５井间马四段的岩性变化进行了分析研究，根据其沉积环境和成岩特点，寻找出它们之间的岩性变化带，进而指出油、气储层的分布规律。     

长春市城区岩土工程地质分区

本次地层岩性分区是通过收集目前长春地区以完成的地质勘察的钻孔资料,再结合专家们对长春地区的实际工作经验,对研究区进行工程地质分区。运用GMS软件对长春市城区地下进行可视化分析．为充分合理利用岩土地基提供依据。     

黑龙江东安金矿床地质地球化学特征初探

东安金矿床是黑龙江省新近发现的具大－特大型远景的浅成热液金矿床，受断裂和隐爆角砾岩带控制，赋存于中生代中酸性火山－侵入岩及晚印支期碱长花岗强硅化带中，成矿与火山－侵入岩作用有密切成生关系。成矿物质主要来源于火山－侵入岩，成矿温度144－348℃，成矿深度约0.2-1.0km，成矿时代为中燕山晚期。     

综合录井地质分析平台

针对目前上交综合录井资料利用率不高的现状,该文提出了开发“综合录井地质分析平台”意见,并系统介绍了研制目的、开发环境和技术关键等内容。以期实现功能强、界面友好、操作灵活,真正成为录井地质师的有效工具。结合录井资料信息量大、随钻实时性和第一性的特点,采用多用户管理等方式,面向用户开放,有利于扩大、提高录井资料的综合利用水平,实现录井资料的广泛应用和信息共享。     

Uncertainties in Geologic Profiles versus Variability in Pile Founding Depth

How the design and actual founding depths of foundations correspond to the variability of geological conditions has long been a concern. This paper evaluates the spatial variability characteristics of as-built and estimated founding depths of driven steel H piles with reference to the spatial variability characteristics of geologic profiles at a weathered soil site in Hong Kong. Spatial variability characteristics are evaluated in terms of variance and scale of fluctuation. The variability of three founding depth indicators, i.e., the depth of Grade-III bedrock, the depth of standard penetration test blow count “N” of 200 blows/0.3 m (SPT-200), and the depth of completely decomposed granite over the site was estimated. It is found that pile founding depths exhibit greater variations than those of the geologic profiles due to the presence of design model errors, judgment errors, and construction effects. The as-built founding depths are mostly between the SPT-200 profile and the Grade-III bedrock profile. The variances of as-built pile length are similar to those with depth of SPT-200 but less than those with depth of Grade-III bedrock. The scale of fluctuation of as-built pile length is on the order of 20 m when kriging is used and 10 m when kriging is not used, which are less than those with depths of SPT-200 and Grade-III bedrock.     

�й�ú����������������̽������

根据中国石油天然气股份有限公司煤层气10年勘探经验教训，借鉴国外成功实例，总结了中国煤层气生气、成因、成藏模式，进行了煤层气勘探目标评价参数分类；提出了不同煤阶区的煤层气勘探新认识；梗概阐述了利用以上理论认识发现沁水煤层气田和大宁含气区的基本地质条件。最后分析了煤层气未来勘探新领域。     

矿产资源评价理论与方法评述

矿产资源评价是一项结构繁杂、功能综合、因素众多的复杂系统工程，矿产资源地质评价是基础，矿床技术经济评价、矿产资源经济评价是企业生产和社会主义市场经济规律所必需进行的，矿产资源环境评价是进行环境管理的重要手段，矿产资源综合评价是一种评价指标相对全面的评价方法。系统评述了矿产资源评价理论和方法的研究状况，预测了矿产资源评价的发展方向。