A quantitative approach to deep-water sedimentation in the South China Sea: Changes since the last glaciation     

Wei Huang  Pinxian Wang 《中国科学D辑(英文版)》1998,41(2):195-201

The first attempt is made to evaluate quantitatively the changes of accumulation rates in the South China Sea during the last glaciation and Holocene, based on the data of 72 sediment cores taken from six areas deeper than 100 m. As shown from the calculations, the accumulation rate during the last glaciation is much higher than that during the Holocene. The southern and northern continental slopes are distinguished from other areas by the highest accumulation rates, with different features of sedimentation for aifferent stages: The Glacial-Holocene contrast in accumulation rate of terrigenous material is more distinct in the southern slope, while the contrast in biogenic sedimentation rate is more remarkable in the northern slope. Project supported by the National Natural Science Foundation of China (Grant No. 49576268).  相似文献   

新疆克孜尔水库形变前兆异常的初步研究   总被引：8，自引：4，他引：4  

杨志荣 《内陆地震》1998,12(2):152-160

对克孜尔水库蓄水前１８ 年的水准、基线测量资料进行研究认为：水准高差正常年变形态的消失是趋势性前兆异常的表现;震前半年左右测值曲线出现较大幅度的上下跳动,或呈台阶状大幅度下降,或出现直线状的“静止不变”异常,则是短临异常的主要特点。研究中发现：（１）异常的形态可能与断层运动的方式和状态有关;（２）异常幅度、异常持续时间与之后发生的中强震的强度及频度有一定关系;（３）近距离强震发生前,断层垂直位移有明显异常,而较远处强震发生前则地表倾斜异常较明显。基线测量没有观测到与水准相呼应的前兆异常  相似文献   

The introduction of neural network system and its applications in rock engineering   总被引：3，自引：0，他引：3  

Yi Huang  Stefan Wnstedt 《Engineering Geology》1998,49(3-4):253-260

The neural network system has been developing very fast recently. It has been widely used in many industries such as automation, nuclear power plant, chemical industry, etc. Neural network systems have a great advantage in dealing with problems in which many factors influence the process and result, and the understanding of this process is poor, and there are experimental data or field data. In rock engineering, many problems are of this nature. In this paper, a brief introduction to neural network systems is given. Problems such as what is a neural network, how it works and what kind of advantages it has are discussed. After this, several applications in rock engineering, made by us, are presented. Case 1 is ore boundary delineation. In this case, the rock are divided into three classes, i.e.: (1) waste rock; (2) semi-ore; and (3) ore for mining purposes. The neural network system built can judge whether it is ore, semi-ore or waste rock along the borehole according its corresponding geophysical logging data, such as gamma-ray, gamma-gamma, neutron and resistivity. Case 2 is aggregate quality prediction. In this case, the quality parameters: (1) impact value; (2) abrasion value I; and (3) abrasion value II are predicted by using a neural network system based on density, point load, content of quarts and content of brittle minerals. Case 3 is rock indentation depth prediction. In this case, the rock indentation depth under indentation load is predicted by the established neural network system based on the indentation load on rock, indenter type and rock mechanical properties, such as uniaxial compressive strength, Young's modulus. Poisson's ratio, critical energy release rate and density. In all these cases, the neural network systems have been applied successfully. The testing results are satisfactory and better than the existing techniques.  相似文献   

含硬包体试样在破裂孕育过程中波速场的变化   总被引：2，自引：2，他引：0  

王彬  胡毅力 《地震研究》1998,21(3):256-260

含硬包体混凝土试样在底面支撑侧面双轴加压至主破裂的情况下波速场的变化图象为：加压初期,试样上的纵波平均速度在４１７５～４６１５ｍ／ｓ之间变化,随着压力升高,出现小于４１７５ｍ／ｓ的低速区,但范围甚小,位置在两个包体之间。随后出现大于４６１５ｍ／ｓ的高速区,范围大致与包体位置一致。随着σ１的增加,低速区在逐渐变大,高速区逐步减小后又重新变大,高速区与低速区在平面上相互重叠,在空间上看,高速区被低速区包围着。临近主破裂时,低速区变小并逐步形成条带,高速区也变小,主要集中在靠近未来出现破裂的一个包体位置上。最终的破裂面出现在此高速区与低速条带交界附近,包体也局部破裂了。  相似文献   

某些测震学指标与地震相关性研究   总被引：3，自引：0，他引：3  

张军  黄显良 《地震》1998,18(2):171-176

通过对１０项测震学指示宾１０ａ的大范围时空扫描得出的有震和无震“预报”进行了与５．０级以上的地震的相关性研究,结果证明这１０项指标当显性水平较低时,均可通过统计检验,表明是有效的提取异常指标。作还依统计检验结果对１０项测震学指标与地震相关性好坏进行了排序,并通过分析得到各指标今后优化方向．  相似文献   

论桩基动力检验法   总被引：3，自引：1，他引：2  

黄龙生  黄勇  李昭芳  巩立军  黄万春 《地震工程与工程振动》1998,18(2):124-133

本文扼要地论述桩基动力检验方法中桩质量诊断及单桩承载力确定的理论,依据及其适用范围,有助于正确运用这一检验方法为工程建设服务。  相似文献   

滁州市会峰大厦桩基垂直静荷载试验研究     

黄永浩  秦厚慈  沈国英 《安徽地质》1998,(1)

本文根据滁州市会峰大厦人工挖孔扩底桩的垂直静荷载试验成果,分析研究了滁州市红砂岩地基嵌岩桩的荷载有受力特征。  相似文献   

淮北煤田上石盒子组花斑泥岩中的粘土矿物研究     

岳梅 《安徽地质》1998,(1)

淮北煤田上石盒子组花斑泥岩中的粘土矿物组合以高岭石为主,伊利石次之。高岭石的结晶度较好。伊利石均表现有混层现象。研究表明,花斑泥岩经历了较强的成岩作用。  相似文献   

试论工程场地砂土液化的综合评判——以福-泉高速公路长乐营前三汊港特大桥为例     

黄莉菁  王善雄 《福建地震》1998,(2)

本文以对营前特大桥桥位区的砂土液化的综合评判为例子,提出砂土液化必须运用定值准则的概念与方法并结合各种宏观液化势判定手段进行综合评判,文中还针对水下孔的水位取值进行了讨论。  相似文献   

甘肃敦煌地区太古宙孔兹岩系特征   总被引：5，自引：0，他引：5  

于海峰  梅华林  李铨 《华北地质》1998,21(1):19-25

本文根据甘肃敦煌地区广泛出露在太古宙TTG杂岩中的一套副变质岩系的岩石组合、典型矿物组合、变质相特征和岩石化学特征的分析,认为它们是一套中深变质的碎屑岩-泥质岩-泥灰岩-碳酸盐建造,其中夹有少量的变质基性火山岩。原岩形成于具有基性火山作用的活动大陆边缘滨海-浅海环境。经过太古宙的区域高角闪岩相变质作用,形成孔兹岩系。  相似文献