广东湛江陨击混杂堆积层的发现及其意义

通过野外地质调查和取样分析,首次在广东湛江地区中更新统早期的北海组地层中发现了一层罕见的陨击混杂堆积层,它是陨击作用下的特殊产物,是北海组含砾砂、粘土质砂在陨击高温作用下烧结、抛射堆积而形成的。陨击混杂堆积层主要分布在湛江坡头的部分地区,有的出露地表,有的为第四系所覆盖,厚度大约为0·1~4m。陨击混杂堆积层中共生玻璃陨石(雷公墨)。陨击混杂堆积层中的击变岩砾石与原岩相比较,Si O2的含量明显减少,Fe2O3的含量明显增加,其他化学成分及含量与原岩近于一致。陨击混杂堆积层的发现可能对澳大利亚—东南亚微玻璃陨石场陨击源坑的寻找和探讨该期玻璃陨石和微玻璃陨石与靶岩之间的关系有重要意义。     

湛江强结构性黏土强度特性的应力路径效应

为探讨湛江强结构性原状土与相应重塑土在不同应力路径下的强度特性及其与结构性的关联性,开展了在不同固结条件下的主动压缩、被动压缩、主动伸长3种应力路径试验,分析了该强结构性黏土在不同应力条件下的力学性状与强度特性。结果表明,湛江黏土的剪切破坏形态主要是单一型、双交叉剪切带与“腰鼓”型3类,应力-应变特性主要为轻度应变软化、强烈应变软化、轻度应变硬化、强烈应变硬化4类;偏压固结下试样破坏应变小于等压固结相应值,破坏强度及初始弹性模量比后者大;不同应力路径下土的强度差异主要反映在结构屈服前有效黏聚力的不同,结构屈服前,原状土的黏聚力高于重塑土的黏聚力,内摩擦角小于后者;结构屈服后,黏聚力逐渐减小,内摩擦角略有增大。原状土到重塑土的转变过程是黏聚力与内摩擦力在土体内部相互消长的过程,强结构性黏土在结构屈服前的强度指标具有较强应力路径依赖性。     

方桩H型桩尖在湛江地区老粘土中的应用

湛江地区老粘土分布广泛,呈硬塑-坚硬状,粘聚力大,力学强度高,对沉桩有一定影响。针对湛江地区较多工程高桩码头方桩沉桩施工中出现裂损或入土过浅的现象,结合湛江奥里油电厂油改煤项目码头工程,设计对方桩锥形桩尖优化为H型桩尖,施工中没有出现桩破损现象,最终贯入度、桩尖标高达到设计要求;施工完成后经检测,桩身质量和承载力满足设计要求,效果良好,可供湛江地区类似工程借鉴参考。     

厦门港深水航道整治工程潮流模型试验和泥沙回淤分析

对厦门港深水航道潮汐水流试验研究和泥沙回淤分析研究结果表明 ,58km长深水航道范围内泥沙总回淤量为 2 80× 1 0 4 m3 a,其中海沧进港航道的墓前礁浅段和猴屿南的嵩鼓水道仍然是回淤率较大的区段 .此外 ,海沧港区的西端由于码头突出原岸线 70 0多米 ,落潮流被挑离码头 ,形成大尺度回流 ,不仅增加了回淤量 ,对船舶靠泊也不利 .对强波浪条件下泥沙集中淤积问题的研究计算结果表明 ,一次大风浪可能造成的回淤率并不大 ,外航道范围内一次大风浪过程 ( 2d)的回淤率不大于 9.0cm d ,内航道不大于 5.0cm d ,港内不大于 2 .5cm d .     

Observation of edge waves trapped on the continental shelf in the vicinity of Makurazaki Harbor, Kyushu, Japan

Sea-bottom pressure gauges were used to measure sea levels at two points on the shelf off the southern coast of Satsuma Peninsula, Kyushu, Japan. Spectral analysis of the observed records and the tide-gauge record of Makurazaki Harbor revealed several predominant common peaks. At the same time, the eigenmodes for the trapped waves on the shelf and inside Makurazaki Bay were obtained numerically using a two-dimensional model, and the periods and the spatial distribution of amplitudes of the proper modes were obtained. A comparison of the calculated modes with the periods and phase patterns of the observed peaks clarified that peaks with periods of 19.5, 16, 13.3, and 12.2 minutes in the shelf region were the modes of standing-edge waves, and the peak with the period of 16 minutes in Makurazaki Harbor was the fundamental mode of the harbor. Among the modes of standing-edge waves, the mode of the period 16 minutes on the shelf had nearly the same period as that of the fundamental mode of Makurazaki Harbor. An analysis of changes of spectral densities of these two modes confirmed that the fundamental mode of the Makurazaki Harbor was induced by this standing-wave mode.     

Changes in the metal content of surficial sediments of Boston Harbor since the cessation of sludge discharge

Temporal trends of metals in surficial sediments (1991-1998) at two sites in Boston Harbor were analyzed to evaluate the effect of stopping sludge dumping in December 1991. Metal contents of sediments from the old sludge disposal site were higher than those of a station in the central Harbor. Since 1991, carbon, copper, and lead contents have significantly decreased in sediments from the disposal site. Chromium and Zn have shown smaller decreases while Fe, and Mn, have remained relatively constant. Metal content in the central Harbor station, located in an area of sediment reworking, has been quite variable, but, with the exception of Zn which has shown a large decrease relative to iron, the changes seemed to be well correlated with changes in the organic carbon content at this site due to resuspension. Ratios of metals in the sediments are fairly similar at both sites and similar to those of sewage-derived particles, with the exception of Cr, which appears to be enriched in the sediments.     

湛江湾填海工程对海床冲淤的影响预测

建立了湛江湾泥沙数学模型,模拟了湛江湾海床冲淤演变,模拟结果表明,湛江湾海床较为稳定,年冲淤强度小,模拟冲淤分布与历史海图资料得出的长期演变趋势符合。模型用于湛江湾围填工程对海床冲淤变化的影响预测,结果表明工程后海床冲淤强度没有明显的改变。另外,优选了围填方案,估计了港池的淤积强度。     

象山港,三门湾潮间带生态学研究：Ⅰ.种类组成与分布

象山港和三门湾地处浙江沿岸带中部，这两个半封闭型港湾的软相潮间带底栖动物种类组成均以广温广布性种占多数，其次为亚热带性种。种类的分布与盐度、潮流流速、悬沙含量以及港湾屏蔽程度等环境因子有关。象山港种类多于三门湾，同一港湾种类呈现湾底多于湾中多于湾口的特点。     

基于模糊综合评判法的湛江市区地下水水质变化分析

地下水在饮用水、灌溉农田和工业生产供水中占有重要地位,湛江市的发展离不开对地下水的开发利用．随着人口增长和经济的发展,湛江市的地下水受到一定程度污染,水的供需矛盾日益突出．本研究应用模糊综合评判法对湛江市市区在2001年和2011年丰水期期间中浅层地下水水质监测点的水质状况进行评价分析,探讨了10年间湛江市地下水水质状况的变化,从评价结果可以看出,2001年Ⅰ类水仅占13％,Ⅴ类水比重高达67％,2011年接近一半的监测点属于Ⅴ类水,超过六成的监测点处于Ⅳ、Ⅴ类水．对比2001年和2011年可以看出,2001-2011年期间湛江市市区中浅层地下水水质状况未有明显变化,地下水受污染程度严重,主要污染物为NH4＋,NO2-和Fe．     

General multidimensional cloud model and its application on spatial clustering in Zhanjiang,Guangdong

Traditional spatial clustering methods have the disadvantage of “hardware division“, and can not describe the physical characteristics of spatial entity effectively. In view of the above, this paper sets forth a general multi-dimensional cloud model, which describes the characteristics of spatial objects more reasonably according to the idea of non-homogeneous and non-symmetry. Based on infrastructures’ classification and demarcation in Zhanjiang, a detailed interpretation of clustering results is made from the spatial distribution of membership degree of clustering, the comparative study of Fuzzy C-means and a coupled analysis of residential land prices. General multi-dimensional cloud model reflects the integrated characteristics of spatial objects better, reveals the spatial distribution of potential information, and realizes spatial division more accurately in complex circumstances. However, due to the complexity of spatial interactions between geographical entities, the generation of cloud model is a specific and challenging task.