【作者】 单红仙；

【导师】 杨作升； 黄润秋；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2003， 博士

【摘要】 本学位论文以国家自然科学基金面上项目“黄河口水下斜坡硬壳的形成与破坏”(项目号：141720888)为依托，旨在研究波浪作用导致的黄河三角洲表层工程地质环境要素，即形貌特征、物质组成、物理力学性质的动态变化过程。 在黄河水下三角洲开发的工程活动中，尽管设计都是针对具体场地的工程地质勘察资料进行的，但在设计方案实施和工程构筑物实际运行中，常因始料未及的工程地质事件发生，造成巨大的损失。胜利油田在1984年-1987年、1994年、1998年多次发生海上插桩失败和暴风浪下采油钻井平台倾斜、输油管破裂漏油。这些地质灾害事件的发生虽然不能完全排除人为误差所致；但同样不能排除的另一类可能，是黄河水下三角洲的工程地质环境处在高度的动态变化中，尤其在极端海况时，工程地质环境要素随时间和空间可能发生剧烈变化。以致对一个拟建工程场地，很难有一个一成不变的地基土体力学指标供设计人员采用。本学位论文研究试图回答这一至今悬而未决的问题，这是本文的立论依据之一。 本文的研究属于波土相互作用中土体对波浪的动力响应范畴。正如在前言中对此方面研究评述所提及，目前的研究被与实际迥异的实验边界条件和过分理想化理论模型制约，迫切需要了解真实的时间和空间尺度下，真实的土体在真实的波浪荷载作用下将发生怎样的变化，以验证和引导我们进行的理论与模拟研究。本学位论文在黄河口选择典型研究区作为天然试验室，从1999年至2002年进行系统的现场和室内试验，试图发现土体对波浪作用的变化响应过程，这是本论文的另一立论依据。 本论文对研究领域进行了评述，包括海床对波浪动力响应研究现状和黄河水黄河水下三角洲表层工程地质环境动态变化研究下三角洲地质环境研究的现状，然后介绍了黄河水下三角洲工程地质环境，交代研究区的背景。之后介绍了现场开展的研究工作，包括工作内容、工作方法、实施过程、结果资料。现场开展的工作有典型研究区选择确定，地形测量，粒度与矿物成分分析样品的采集，钻探及用于土工测试和微结构观测的原状土样的采集，轻型静力触探试验，静力触探试验，动力触探试验，十字板剪切实验，土体振动实验和水动力测量。随后介绍了实验室内开展的研究工作，包括测试项目、测试方法、结果资料。室内测试分析主要有土样动三轴实验，矿物组成X衍射分析，土样微结构扫描电镜观测，土样粒度成分分析和常规土工实验分析。在此基础上，针对现场和室内实验取得的结果资料，采用一系列统计分析方法，定量描述水动力作用导致的黄河口典型研究区工程地质环境要素随时间和空间的变化，包括形貌特征对水动力条件响应、沉积物的粒度与矿物成分及结构对水动力条件的响应、沉积物的静力与动力学指标对水动力条件的响应。 典型研究区选择的标准是，能反应出在真实的时间尺度和空间尺度下，显著差异的波浪作用条件导致的工程地质环境的变化。选定的研究区位于黄河1964一1976年由刁口流路入海时沉积形成的三角洲叶瓣潮坪上，低潮时出露水面，高潮时水深1.5米左右。1995年为极浅海石油开采在其上构筑的一条道路，形成了一个水动力屏障。道路北侧处于迎浪向，具有强的水动力条件:道路南侧处于背浪向，水动力条件弱。现场水动力实测结果表明，在平静海况时道路北侧典型区I的有效波高15厘米，道路南侧典型区H的有效波高6厘米。极端海况时两者的差异将更加显著。相同的初始工程地质环境条件，显著差异的水动力作用条件，足够长的作用时间，以及退潮时变成陆地的工作条件，使得其成为研究波浪作用导致海床工程地质环境动态变化理想天然实验室。 大量密集的现场原位土工测试工作和样品采集工作，于1999年和2002年在道路南北两侧所划定的典型区工和典型区H重复进行，以研究比较水动力差异作用导致的海床工程地质环境要素随空间和时间的变化。同时，为了在更大的范围研究差异性波浪作用可能导致的沉积物的次生变化，沿着黄河三角洲的周边，从 2黄河水下三角洲表层工程地质环境动态变化研究具有中等水动力作用强度的三角洲西北部埋子口，到强水动力作用的三角洲北部刁口，到弱水动力作用的三角洲东南部广利港，进行原位土工测试，研究潮坪沉积物力学强度指标变化。 研究发现，黄河水下三角洲工程地质环境要素对水动力作用具有显著响应，不同的波浪作用强度导致水下斜坡形貌特征、物质组成与结构、物理力学性质发生了一系列的差异变化，研究结论如下。 1、首次采用分维值对不同水动力条件的潮坪区底坡形貌特征、沉积物粒度组成和沉积物强度动态变化进行定量性评价，为研究黄河水下三角洲的工程地质环境动态变化提出了新的评价指标和评价方法。 2、通过对波浪荷载作用下不同水动力潮坪区工程地质环境要素动态响应特征的研究发现，潮坪区滩面分维值、沉积物粒度分维值、沉积物矿物成分、沉积物结构、沉积物强度等值曲面分维值对波浪荷载作用有强烈的?更多还原

【Abstract】 The dissertation was relied on the project of National Nature Science Foundation Project Formation and failure of hard crust on the subaqueous delta of Yellow River(Contract No. 141720888), and objective to research dynamic variation of engineering geological environmental factors i.e., topographic and morphologic features, composition and structure, physical and mechanical properties on the subsurface of Yellow River Delta, that was induced by wave loading action.Because of the engineering geological happening, the magnitude losing have often taken place on the process of design actualizing and engineering building practicality running though the designing is provided with engineering geological investigation measure of the field on engineering exploitation activity of the Subaqueous Delta of Yellow River. It occurred many times on the ocean of Shengli Oil Field that driving piles were defeated, artesian well flat roof leaned, oil transport pipe brook and oil leaked in the year of 1984, 1987, 1994 and 1998. It wasn’t be obviated by man-made error and dynamic variations of engineering geological environment on the Subaqueous Delta that these geological hazard events occurred. Especially in the extreme of marine condition, the element of engineering geological environment was acutely variation in time and space. It is difficult to design a series invariable mechanics index of soil for designer adoption in a plan constructed engineering field. The dissertation will want to answer this unsolved question so for. It is one point of the dissertation.The dissertation research question belongs to the response of soil changing induced by dynamic wave load in the interacted area of soil and wave. So for, because of the restriction of experiment boundary condition that different original condition and over ideal theorization model that is mentioned in the preface, it is imminence needs to understand the changing of reality soil on the true wave loading in true time and space so that validated and lead next research in theory and simulation. The suitable study area that is natural laboratory and has representative will be selected in the dissertation, a series tests of in-site and laboratory have been carried through in the year of 1999 and 2002, the response process of soil in wave load are tried to be disappeared. This is the other one point of the dissertation.In the preface, review on relative research fields was given, included reviews of sea bed dynamic reaction to wave action research and engineering geological environment research of subaqueous delta of Yellow River, brief instruction about the thesis’s idea was presented also. The body of dissertation can be divided into 12 chapters. The chapter 1 resumed the engineering geological environment of subaqueous delta of Yellow River, China. The chapter 2 instructed field work, including content, method, procedure and results. The conducted work in field contained case study area selection, topo survey, sample collection for grain size and mineral composition analysis, bore hole drilling and catching undisturbed soil samples for soil test and microstructure observation, portable cone penetration test, cone penetration test, dynamic penetration test, vane shear test, soil vibration test and hydrodynamic measurement. The chapter 3 instructed laboratory work, including test content, method and results. The lab tests contained soil dynamic triaxial test, X ray diffraction, scanning electronic microscope observation, grain size analysis and routine soil tests. From Chapter 4 to Chapterl 1, a serial of comparable methods were adapted to analyze the obtained results in Chapter 2 and Chapter 3, in order to describe quantitatively the changing of engineering geological environmental factors with time and space that is induced by different waveloading action, including reaction of topo and morphologic features to hydraulic condition, reaction of grain size and mineral composition to it and reaction of static and dynamic mechanical index to it. The Chapter更多还原