天津近海海底地质灾害类型及声学特征     

赵卫  熊元凯  宫少军  詹华明  乔吉果 《海洋科学》2021,45(2):119-126

作者利用浅地层剖面资料研究了天津近海海域存在的主要海底地质灾害。研究发现:浅层气、埋藏三角洲前缘、水下潮流沙脊、陡坎、沙波等地质灾害发育。浅层气主要分布在研究区北部海域的近岸附近,南部海域远离海岸浅层气逐渐增多;埋藏三角洲前缘分布区北至涧河口,南至南港工业区东部海域;水下沙脊分布于北部海域5 m~7 m水深的近岸带,地层内部前积斜层理发育;沙波区延伸长度约3 km,整体上在天津海域分布较少;海底表层陡坎出现在天津港及以南海域,其成因主要是航道两侧边缘陡坎或因吹填而抽走的泥沙造成的,近岸及远海地区均有分布。  相似文献   

Elastic solutions for a transversely isotropic half-space subjected to buried asymmetric-loads     

C. D. Wang  J. J. Liao 《国际地质力学数值与分析法杂志》1999,23(2):115-139

Elastic closed-form solutions for the displacements and stresses in a transversely isotropic half-space subjected to various buried loading types are presented. The loading types include finite line loads and asymmetric loads (such as uniform and linearly varying rectangular loads, or trapezoidal loads). The planes of transverse isotropy are assumed to be parallel to its horizontal surface. These solutions are directly obtained from integrating the point load solutions in a transversely isotropic half-space, which were derived using the principle of superposition, Fourier and Hankel transformation techniques. The solutions for the displacements and stresses in transversely isotropic half-spaces subjected to linearly variable loads on a rectangular region are never mentioned in literature. These exact solutions indicate that the displacements and stresses are influenced by several factors, such as the buried depth, the loading types, and the degree and type of rock anisotropy. Two illustrative examples, a vertical uniform and a vertical linearly varying rectangular load acting on the surface of transversely isotropic rock masses, are presented to show the effect of various parameters on the vertical surface displacement and vertical stress. The results indicate that the displacement and stress distributions accounted for rock anisotropy are quite different for those calculated from isotropic solutions. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

A small-scale field check on the Fisher–Lehmann and Bakker–Le Heux cliff degradation models     

J. N. Hutchinson 《地球表面变化过程与地形》1998,23(10):913-926

The paper considers the development of initially straight, steep rock cliffs, bounded above and below by horizontal surfaces, in which basal debris removal is zero and degradation occurs by the weathering away of fine debris from the cliff face to form a scree at its foot. Of the slope degradation models available, the two earliest and simplest, namely the Fisher–Lehmann and the Bakker–Le Heux models, are regarded as most relevant and are briefly summarized. The main purpose of the paper is to check the predictions of these models, particularly with regard to the shape of the rock surface buried beneath the scree, against field data. Such data are sparse. It is concluded that the best field case currently available, despite its small scale, is that provided by the 1·75 m deep ditch which forms part of the experimental earthwork in the chalk on Overton Down, Wiltshire. The predictions of the two models are checked against field measurements made of the stage of degradation reached on each face of the ditch by July 1968, eight years after its excavation. These stages were influenced to different degrees by the presence of a surface turf layer. For the NE face, where this influence was least, the agreement of the predictions of the Fisher–Lehmann model with the actual rock profile is excellent and that of the Bakker–Le Heux model only marginally less so. For the SW face, as expected, the agreements are somewhat less close. These results may be to some extent fortuitous because of the influence of the turves and because the scree slopes tend to be concave rather than rectilinear, as assumed. Also, the free faces decline with time in a manner intermediate between those assumed in the two models. Larger scale field checks are clearly desirable before firm general conclusions can be drawn. Rates of crest recession for the Overton Down ditch are logarithmic with time after a very rapid initial phase. Extrapolation from the early phase of this logarithmic behaviour leads to a close estimate of the time needed for the slope to develop fully. The associated ultimate crest recession is also closely predicted by equations derived from both models. © 1998 John Wiley & Sons, Ltd.  相似文献   

水井测温在地热普查中的应用          下载免费PDF全文

杨斌  牛保祥 《山东国土资源》2005,21(9):65-66,70

利用水井测温方法确定恒温层温度,以恒温层的温度值作为湖顶地热异常区的下限值,用内插法勾绘温度等值线图,高于该下限值范围的即为地热异常区。曹县庄寨地区的地热普查证明该方法是快速有效的。  相似文献   

Behaviour of continuous pipeline subject to transverse PGD     

Xuejie Liu  Michael J. O'Rourke 《地震工程与结构动力学》1997,26(10):989-1003

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古近系半成岩地铁车站深埋隧道矿山法施工变形规律     

王炳华  王中华  高涛  廖鹏  陈维  潘洪义 《测绘通报》2020,(9):12-17

本文以南宁轨道交通3号线青秀山站为例，研究了古近系半成岩地铁车站深埋隧道矿山法施工变形规律及施工方法，设计了专项监测方案，对矿山法大断面施工的各项监测数据进行分析研究，重点分析了CD法和三台阶法等不同工法的初支结构变形情况。研究表明，做好地下水的控制可以保障深埋隧道安全开挖和控制周边环境变形；CD法和三台阶法在古近系半成岩粉砂岩、泥质粉砂岩，局部粉（细）砂岩等地层中均可以满足初支结构变形要求；CD法和三台阶法均可以选择的情况下，三台阶法更为经济。  相似文献   

东秦岭地区浅隐花岗岩体遥感识别模式     

张天义  朱嘉伟 《河南国土资源》1996,(4)

在含金地层分布区，研究揭示隐伏岩浆热源活动特征及基底导岩导矿构造特征是寻找隐伏金矿床的技术关键。本文依据花岗岩体侵位动力学及热力学机制，阐明了线、环同现构造影像的形成机理及其所揭示的地质内涵，指出了环形影像构造成因的多解性，提出了如何从纷杂的“环、线”影像构造中提取出反映岩体侵位这一特定影像构造的原则及其重要性，以遥感技术为主导，综合应用地质、物化探技术，建立了“环状影像构造－斜磁化场－重力亏损场－岩浆期后热液活动中心的多元信息同现”隐伏成矿花岗岩体的遥感综合判读模式，实现了遥感解译由模糊—定性—定量化的综合解译判读过程。论证了东秦岭一些地区存在着规模宏大的燕山期浅隐伏成矿花岗岩体，并定量解译了隐伏花岗岩体的形态、产状及规模，指出金及其伴生元素的含矿热液活动受隐伏岩浆活动及基底导岩导矿构造双重因素控制  相似文献   

Morphostructures and Cenozoic deposits on the right bank of the Kizir River (East Sayan)     

N.N. Popova  A.V. Matsera 《Russian Geology and Geophysics》2008,49(5):332-336

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脉动激励下的浅埋管道轴向应力分析     

任建亭  侯庆志 《岩土力学》2008,29(3):645-650

考虑土体-结构-流体耦合作用,研究流体脉动对浅埋输液管道轴向应力的影响.基于流固耦合、管-土耦合理论,建立了浅埋管道动力学分析模型,应用力平衡条件,推导了浅埋管道的静力及动力方程,并利用行波方法求取了动力方程的解析解.在此基础上,研究了管道应力特性.结果表明:流固耦合对浅埋管道应力有较大影响,较小幅值的压力脉动可使管道应力大幅增加.同时,讨论了管道埋深、土质条件及管道半径对管道应力的影响.在相同流体脉动激励下,管道应力随覆盖层厚度、土体刚度、管道半径增加而减小.  相似文献   

济阳坳陷孤西负反转断层形成演化定量研究及其油气地质意义   总被引：1，自引：0，他引：1  

雷超  任建业  吴梅莲  祁鹏  胡德胜 《大地构造与成矿学》2008,32(4)

以高精度三维地震资料和钻井资料为基础,对研究区断裂构造进行精细解释,确定孤西断层为"薄底型"的、且表现为北段缓而南段陡、并向西倾的负反转构造;通过回剥技术和平衡剖面等定量分析技术对垂直穿越孤西断层的典型地震剖面研究揭示,孤西断层在J3-K1时期断层性质发生改变,由逆断层反转变为正断层,且在印支、J3-K1和Ek-Es4时期剖面拉伸率分别为-4%,17.2%和18.5%;沿孤西断层走向方向不同位置计算其断层活动速率表明该断层整体经历了负反转运动。以上述分析为基础,论文从烃源岩、圈闭、储集岩和油气运移角度,探讨了孤西负反转断层在孤岛潜山油气成藏方面的重要意义。  相似文献