Elastic solutions for stresses in a transversely isotropic half‐space subjected to three‐dimensional buried parabolic rectangular loads

In many areas of engineering practice, applied loads are not uniformly distributed but often concentrated towards the centre of a foundation. Thus, loads are more realistically depicted as distributed as linearly varying or as parabola of revolution. Solutions for stresses in a transversely isotropic half‐space caused by concave and convex parabolic loads that act on a rectangle have not been derived. This work proposes analytical solutions for stresses in a transversely isotropic half‐space, induced by three‐dimensional, buried, linearly varying/uniform/parabolic rectangular loads. Load types include an upwardly and a downwardly linearly varying load, a uniform load, a concave and a convex parabolic load, all distributed over a rectangular area. These solutions are obtained by integrating the point load solutions in a Cartesian co‐ordinate system for a transversely isotropic half‐space. The buried depth, the dimensions of the loaded area, the type and degree of material anisotropy and the loading type for transversely isotropic half‐spaces influence the proposed solutions. An illustrative example is presented to elucidate the effect of the dimensions of the loaded area, the type and degree of rock anisotropy, and the type of loading on the vertical stress in the isotropic/transversely isotropic rocks subjected to a linearly varying/uniform/parabolic rectangular load. Copyright © 2002 John Wiley & Sons, Ltd.     

Quaternary stratigraphy of the buried valleys of the lower Red Deer River,Alberta, Canada

The Quaternary fills of the buried valleys of southern Alberta and Saskatchewan have provided a wealth of information for the reconstruction of the glacial-interglacial record of the western plains of Canada, and this paper reports on the previously unstudied stratigraphy of the buried Calgary Valley and its former tributaries in the lower Red Deer River area. We attempt to differentiate Empress Group sediments, which potentially relate to pre-glacial, interglacial/ interstadial and post-glacial lake and river deposition, using sedimentology, stratigraphy and palaeoecology. Twenty-nine stratigraphical logs indicate that Empress Group sediments have infilled a considerably large area of badlands and tributary coulees that once drained into the Calgary Valley, located 15 km to the north of Dinosaur Provincial Park. Radiocarbon dates of 52.4 ka, 27.4 ka and > 42.4 ka and glacially modified quartz grains suggest that at least some of the valley fills date to interglacial or interstadial periods and may be mid-Wisconsinan in age. However, outcrops of an older till overlying other valley fills suggest that the buried valleys were only partially excavated during interglacials/interstadials and that older (even pre-glacial) sediments could have survived. Subglacial channels, recognisable on air photographs, largely coincide with buried valley positions due to the preferential excavation of the Quaternary sediment by meltwater and are filled with post-glacial lake sediment from which a radiocarbon date of 16 ka BP was obtained. Pre-glacial and glacial/post-glacial Empress Group sediments are lithologically indistinct but cover a large time span in southern Alberta.     

辽河断陷大民屯凹陷静北潜山孢粉化石新发现

静北潜山的油气勘探始于上世纪70年代初,并将钻井揭示的未见化石的碳酸盐岩和石英砂岩沉积划归中元古界长城系,沿用至今.2002年在对该区的地层研究中,首次发现了晚古生代孢粉化石,从而证实静北潜山存在晚古生代地层.本文以孢粉化石为主要依据,对潜山地层进行了重新划分,并与邻区进行对比.在此基础上对本区的构造和沉积作一讨论.     

东营凹陷王家岗地区王古1潜山构造特征及油气成藏条件

进一步了解王古1潜山的构造特征及成藏条件,利用渤海湾盆地济阳坳陷东营凹陷王家岗地区的大量三维地震剖面和一些钻井资料,并结合东营凹陷南坡缓坡带区域构造背景及成藏条件分析认为,王古1潜山初始发育于印支期,后经燕山期拉张断陷,切割为断块并抬升,最后于燕山期定型,为典型的缓坡盆倾残丘潜山。该潜山被NW向和NE向断裂切割,潜山高部位侵蚀风化严重,上覆孔店组盖层及沙河街组烃源岩,油气通过断层和不整合面运移至潜山顶部形成侵蚀残丘型油气藏。     

断阶型潜山带地质模型的建立及储层预测--以CG20潜山为例

以 CG2 0潜山为例 ,从建立地质模型入手 ,包括地层模型、构造模型、储集模型、储盖组合模型、速度模型等 ,认识到各套地层分布和储层物性的差异均与地震响应密切相关 ,因此可以利用地震波的信息 ,预测潜山储层的发育及分布情况。在对 CG2 0潜山进行精细全三维构造解释的基础上 ,探讨性地应用了测井约束反演、吸收系数、相干分析及三维模式识别等技术 ,对潜山储层进行了预测 ,从而提高了潜山勘探的效益 ,并为类似断阶型潜山带的勘探提供了成功的经验 ,具有一定的指导意义。     

甚低频电磁法在哈尔楚鲁图银-多金属矿区控矿构造特征分析中的应用

以哈尔楚鲁图银-多金属矿床为例,阐述了甚低频电磁法(VLF-EM)在覆盖区控矿构造特征分析及隐伏矿体找矿预测中的应用。VLF-EM测量和地质解释成果表明:矿区内断裂构造主要有NWW、NNW及NE三个方向。其中,NNW和NWW向断裂为主要含矿构造,二者构成菱形网格状或雁列式控矿构造基本格局,断裂交汇地段为形成较大矿体的有利地段;NE向断裂未见工业矿体产出,对矿体起到错断和破坏作用。     

对河南省栾川县大练沟泥石流治理的经验总结

随着国民经济迅速发展,对矿产资源的需求日益增多,20世纪七、八十年代的开采只追求产量和经济效益,而忽视了对环境的保护,开采的矿渣乱排乱放现象非常严重,严重破坏了环境,象这样的矿山在全国各地有很多,随着时间的发展,松散堆积的矿渣在洪水的作用下顺着沟道倾泻而下,形成泥石流,对下游的人民生命财产造成严重的破坏和威胁,矿山泥石流逐步发展,进入发展期和活跃期,必将造成更大的危害。因此对这样的泥石流沟进行研究和治理是很有必要的。在对河南省栾川县大练沟泥石流的治理过程中,得出以下几点体会,现总结归纳出来,希望对类似泥石流沟的治理提供借鉴。     

渤海湾盆地埕岛油田缝洞型潜山油气藏构造及储层特征

埕岛油田古潜山油气藏为典型的缝洞型碳酸盐岩油气藏。埕岛地区经历了多期次的构造运动,并经受了多期次的断裂与剥蚀作用,为油气成藏创造了良好条件。埕岛油田古潜山可以划分为三个构造单元,即埕北20断层下降盘的西排山,上升盘的中排山和东排山,三个潜山带成帚状敛于凸起最南端,为几个二级构造单元交汇处,构造应力较发育。埕岛油田有三种储集空间类型:晶间孔隙、溶蚀孔洞和裂缝。     

渤海湾西部声纳探测发现全新世埋藏槽谷

声波探测具有很高的分辨率和信号发射频度，可以获得高品质浅地层剖面，显示出沉积地层的结构与构造细节、斜层理等三角洲沉积标志特征。展示了渤海湾西部浅地层声纳探测原始记录。探测发现，在大沽口以东27km处存在一个以前不为人知的埋藏槽谷，涉及地层的时代为晚更新世末期与全新世中期。宽达几百米到1km，深约30m，走向北北西，形成时代距今约5000-6000a，可能代表了某种重大地质事件，其成因有溺谷充填和构造断陷2种可能。     

厚层覆盖区综合物化探方法找金试验研究——以广西兴安金石金矿为例

在兴安金石金矿外围 4号分散流异常区 ,通过地电化学提取金测量法 ,查明测区存在 5个走向规模小于 5 0 m的金异常区 ,W( Au) 最大值为 72 .4× 10 - 9,高出背景值十几倍 ,并藉综合土壤吸附汞测量 ,高精度磁测和激发极化法等多种物化探方法来确定这些异常区的地质、地球化学和地球物理特征 ,提出金矿成矿的有利部位在金的地电提取高异常区、高汞量异常区、高磁性异常区、低视电阻率异常区和中等视极化率异常区的“三高一低一中”的找矿模式。确定测区的北北东角 (右下角 )一带具备有利的金矿成矿条件