浅析长沙市地质灾害发育特征及防治对策

长沙市是湖南省地质灾害的多发区之一。地质灾害不仅造成生命财产的巨大损失,而且对当地的投资环境乃至社会的持续发展都构成严重威胁。在介绍了长沙市的区域自然地理与地质环境,阐述了研究区内的滑坡、崩塌、不稳定斜坡、地面塌陷、泥石流等地质灾害的发育特征和形成条件的基础上,全面分析研究地质灾害的发展趋势,并结合当地经济条件与地质灾害现状,给出了较为切实可行的地质灾害防治对策,为长沙市的防灾、减灾和促进区域经济社会可持续发展提供科学依据。     

Early Mesozoic deformations of the eastern Yanshan thrust belt, northern China

The Yanshan thrust belt (YTB) is located at the northern edge of the North China plate. Because of the intense thicking and subsequent delamination of the lithosphere in north China, geologists have been focused on the Late Mesozoic deformation in the Yanshan belt. The Yanshan belt has been regarded as part of a stable craton from the Proterozoic to the early Mesozoic. In this paper, the authors present that the Yanshan area was deformed during the early Mesozoic. This deformation could be related to ocean basin closure along the northern margin of North China, or related to the collision between the north China and Yangtze Plates along the Qinling-Dabie ultrahigh pressure belt. Three stages of early Mesozoic deformation are identified in the eastern Yanshan at Lingyuan County. The first stage is characterized by westward thrusting (D1), the second stage comprises a top-to-east thrust system (D2), and the third stage comprises extensional gravity-induced collapse and landsliding (D3). The timing of these evens is constrained by both the crosscutting relationships of faults and the isotopic dating of volcanic rocks and gravels. The D1 and D2 events took place in the Late Triassic and Early Jurassic, whereas D3 event occurred at the end of the Middle Jurassic. The Dengzhangzi formation was deposited during the D1–D2 period and recorded a rapid uplift, erosion, and deposition sequence. These early Mesozoic contractional deformations in the YTB were probably related to the closure of ancient Asian ocean and ancient Qinling ocean. The later crustal extension was caused by gravitational collapse of the eastern China plateau during early Mesozoic.     

中亚地区阿姆河盆地查尔朱、布哈拉阶地构造特征及演化

阿姆河盆地是中亚地区重要的含油气盆地,位于阿姆河北岸的查尔朱阶地和布哈拉阶地为盆地的二级构造单元,其油气资源量占全盆地的一半。油气主要富集于阶地的局部背斜构造和生物礁圈闭中,这些圈闭与该区构造形成演化密不可分。利用常规地质资料,通过精细地层对比和地震资料解释,识别出两个关键界面:侏罗纪末的断拗转换面和早第三纪末的区域角度不整合面,并结合板块构造理论确定了构造变形时期。研究认为,侏罗纪以来两阶地经历了侏罗纪—白垩纪断陷—拗陷期和早第三纪抬升—改造期两个重要演化阶段,形成了上、中、下三大构造层。断陷—拗陷阶段的沉积控制了该区的构造格局;中构造层膏盐层的发育丰富了后期的构造样式。早第三纪—晚第三纪的构造运动使该区构造发生了强烈变革,形成了典型的逆断裂、走滑断裂带和不对称复合背斜构造带。     

Impact assessment of the "Grain for Green Project" and discussion on the development models in the mountain-gorge regions

To restore China’s degraded ecological environment, the government has launched an environmental restoration project named the “Grain for Green Project” (GGP) in 1999. From 1999 to 2010, the government will spend 40 billion dollars to convert 147 million ha of croplands and 173 million ha of wastelands into forestlands and grasslands in 25 provinces, municipalities and autonomous regions. A primary goal is to replace cropping and livestock grazing in fragile areas with trees and grass. Given the tremendous scale and great number of participants in the project, the attitudes of the affected farmers and the future development in the area where GGP is implemented have a direct influence on the success of the project. To gain a clear idea about the farmers’ attitudes towards the project and put forward the development models for the forestlands converted from croplands, two case sites in the mountain-gorge region in Nujiang River are selected as the study areas, and the methods of field survey and semi-structured interview are adopted to make interviews with more than 100 households in 2002 and 2003 in order to quantify the farmers’ opinions about the GGP and how it has affected their livelihood, socio-cultural and industrial structures, etc. The results are as follows: 1) the project has a certain influence on the farmers with better economic basis and exerts greater influence on the farmers living in the low-elevation regions than on those living in the regions with middle-high elevation; 2) the production models of the local farmers has changed from cultivation and animal husbandry to forestry and sidelines due to the project and the income structure has changed from animal husbandry as main income source to state subsidy and sideline as main income sources; 3) the reduction in the grain income and decrease in the quantity of livestock because of the project have led to the diminution in the total income of the farmers; 4) the project has resulted in changes in the lifestyles and architecture styles of the local farmers, and the traditional “huotang” culture has gone away after the implementation of the project; 5) energy utilization has changed from firewood to methane and electricity in the wake of the implementation of the project. The above-mentioned study results have indicated that the GGP has truly exerted influence on the livelihood and production of the local farmers. Therefore, it is very necessary to make a research into the development models in the forestlands converted from croplands to resolve the problems of the farmers’ livelihood and production. The study results will provide some references for the sustainable development of the mountain-gorge regions.     

我国煤矿矿井地质工作发展阶段概述

矿井地质是一门探索性、适用性都非常强的技术科学,是在煤田地质勘查的基础上、在矿井建设和生产期间、直接为煤矿建设和生产服务的一项重要技术基础工作。我国的矿井地质工作是随着煤炭工业的迅速发展而建立和发展起来的,并积累了丰富的实践经验,逐步形成了一套比较完整的工作内容和工作方法,它对煤矿建设和生产起着重要的作用,其发展历程可划分为四个阶段:初期创立阶段、曲折发展阶段、开拓前进阶段和发展提高阶段。随着我国经济的快速发展,煤炭需求量也随之持续增长,煤炭开采逐步向深部等难采块段及边缘地区推进,其地质条件日趋复杂,开采难度加大,因此矿井地质工作必须做好基础地质的研究工作,重视高新技术应用,完善地质保障体系,逐步提高勘探精度。     

编制煤炭资源储量报告常见问题及注意事项

《煤、泥炭地质勘查规范》实施以来,因对规范、规定、通知、办法的理解差异,在煤炭资源储量报告评审、备案工作中出现了诸多问题,如矿权范围确定、资源储量估算、煤质分析、探采对比、煤层气综合评价、技术经济评价、报告编制等等,针对该类问题,提出了其相应的界定标准和注意事项,以期提高报告质量。     

高位钻场长钻孔在淮南刘庄煤矿瓦斯抽采中的应用

刘庄煤矿东二采区121102工作面所开采的11-2煤层为非突出煤层,但在工作面回采期间,存在瓦斯突出的可能。为防止工作回风巷尤其是上隅角瓦斯超限,确保工作面的正常生产,同时兼顾瓦斯资源的抽采利用,施工了最大长度496m,钻孔直径133mm的瓦斯抽采孔。实际应用表明,该孔投入使用后,整个工作面回采过程中均未发生过瓦斯超限现象,说明利用大口径长距离钻孔取代巷道抽放瓦斯是完全可行的。本文介绍的高位钻场长钻孔的设计、施工和瓦斯抽采情况,可以为今后同类工作面中长钻孔的施工提供借鉴。     

地震纵波技术预测煤层瓦斯富集区的探讨与实践

基于国内外煤层瓦斯富集的岩石物理及地球物理响应的研究成果,提出了以煤层反射波振幅、频率及衰减等动力学特征变化为主要研究对象的地震纵波预测技术方案;探讨了利用叠后Gamma拟合声波约束反演、频谱分解属性分析和叠前AVO反演、弹性阻抗反演等纵波技术预测煤层瓦斯富集性的理论依据及实现方法。上述技术在沁水盆地进行了预测尝试,其获得的含气性预测成果与探井实测的瓦斯富集情况基本吻合,初步证明了上述纵波预测技术方法在开展煤层瓦斯富集区研究方面的可行性和有效性。     

BP神经网络在基坑变形预测分析中的应用

本文提出了基坑变形预测与分析的BP神经网络方法,建立了基坑变形预测分析的模型,应用MATLAB语言编制计算程序进行计算并与实际工程监测值进行比较,从而验证了神经网络在基坑变形预测分析中的可行性、有效性。     

Spatial patterns and environmental associations of deep scattering layers in the northwestern subtropical Pacific Ocean

The mesopelagic communities are important for food web and carbon pump in ocean, but the large-scale studies of them are still limited until now because of the difficulties on sampling and analyzing of mesopelagic organisms. Mesopelagic organisms, especially micronekton, can form acoustic deep scattering layers (DSLs) and DSLs are widely observed. To explore the spatial patterns of DSLs and their possible influencing factors, the DSLs during daytime (10:00–14:00) were investigated in the subtropical northwestern Pacific Ocean (13°–23.5°N, 153°–163°E) using a shipboard acoustic Doppler current profiler at 38 kHz. The study area was divided into three parts using k-means cluster analysis: the northern part (NP, 22°–24°N), the central part (CP, 17°–22°N), and the southern part (SP, 12°–17°N). The characteristics of DSLs varied widely with latitudinal gradient. Deepest core DSLs (523.5 m±17.4 m), largest nautical area scattering coefficient (NASC) (130.8 m2/n mile2±41.0 m2/n mile2), and most concentrated DSLs (mesopelagic organisms gathering level, 6.7%±0.7%) were observed in NP. The proportion of migration was also stronger in NP (39.7%) than those in other parts (18.6% in CP and 21.5% in SP) for mesopelagic organisms. The latitudinal variation of DSLs was probably caused by changes in oxygen concentration and light intensity of mesopelagic zones. A positive relationship between NASC and primary productivity was identified. A four-months lag was seemed to exist. This study provides the first basin-scale baselines information of mesopelagic communities in the northwest Pacific with acoustic approach. Further researches are suggested to gain understandings of seasonal and annual variations of DSLs in the region.