公路隧道位移智能反演与稳定性分析

阐明了公路隧道位移反演的重要性及公路隧道监控量测方法,在此基础上介绍了公路隧道智能反演的原理及过程。通过隧道工程实践证明了隧道位移智能反演的可行性、正确性与实用性,对隧道围岩稳定性分析评价、智能化施工有重要意义。     

成因层序地层学的回顾与展望

回顾了以成因地层层序为基础的成因层序地层学的形成、发展与研究现状,对成因地层层序及其内部构成、高分辨率成因地层层序、成因地层层序的旋回性、非海相成因地层层序、成因地层层序与沉积物堆积速率等主要观点作了简略评述,并结合我国陆相沉积特征对成因层序地层学未来研究前景作了初步展望。     

Response surface and genetic method of deformation back analysis for high core rockfill dams

High core rockfill dams exhibit complex deformation mechanisms because of complicated geological conditions, many material partitions and severe weather conditions. When realistic parameters cannot be obtained through laboratory tests or engineering analogies because of effects of size or time, back analysis is necessary to predict deformation characteristics. This paper proposes a method of deformation back analysis based on the response surface method and genetic optimization theory. The parameters of the creep and Duncan–Chang models for the Pubugou gravelly soil core rockfill dam are sequentially calculated. Back analysis performed using this method efficiently yields more precise results than those obtained from laboratory-determined parameters.     

Present-day sediment dynamics of the Sanaga catchment (Cameroon): from the total suspended sediment (TSS) to erosion balance

ABSTRACT

Total suspended sediment (TSS) data for 1960–1970 and from recent investigations (1990–2000) are used to evaluate the variability in sediment yield of the Sanaga catchment (Cameroon) and the equivalent rates of erosion. At the annual and seasonal time scales, total suspended sediment concentrations for the Mbam sub-catchment are three to four times higher than for the Sanaga basin, reflecting the higher sensitivity of the former to erosion. Classical clockwise hysteresis loops are observed in both sub-catchments, despite a significant increase in human-induced catchment changes. At the multi-year time frame (over a 40-year period), it appears that the second half of the 1990s is marked by a downward trend in TSS. This shift is due to the control infrastructures (river impoundments and ponds) installed in certain parts of the whole catchment, combined with a drop in annual rainfall and river discharge.

Editor Z.W. Kundzewicz; Associate editor not assigned     

一种地物关系约束下的线阵影像坐标反投影计算方法

坐标反投影计算是线阵影像基于严格模型几何校正的关键步骤。本文在分析线阵摆扫式影像的成像方式及其特点的基础上,针对传统基于像方的顺序或迭代搜索方法效率低下的问题,提出了一种利用地物关系约束的坐标反投影计算方法。首先将当前相邻点的最佳扫描行作为先验值,估算其与当前点最佳扫描行的距离,定位初始最佳扫描行;然后以初始最佳扫描行为中心构建搜索窗口,进行最佳扫描行精确搜索;最后根据最佳扫描行对应的外方位元素进行坐标反投影计算。通过对机载线阵摆扫式模拟影像数据和推扫式真实影像数据的试验,验证了该方法的可行性、准确性和高效性。     

西太平洋岛弧-弧后盆地热液活动与硫化物特征

基于国内外研究成果对西太平洋岛弧-弧后盆地热液活动的分布规律、扩张速率、水深以及热液硫化物的矿物组成与金属品位等特征进行探讨。西太平洋岛弧-弧后盆地热液硫化物区以活动型热液区为主,受扩张速率的影响明显主要分布在20～60 mm/a地区;水深分布规律主要受所处构造单元的水深特征控制,而非由热液硫化物区的形成特征所决定;研究区内的热液产物主要为富Zn-Cu、富Ba-Zn以及富Fe-Cu型硫化物;热液硫化物中冲绳海槽具有最高的Ag、Pb含量,劳海盆具有最高的Zn含量,马努斯海盆和伊豆-小笠原-马里亚纳海槽具有较高的Au含量,北斐济海盆具有最高的Cu含量。本研究将进一步为西太平洋岛弧-弧后盆地地区热液硫化物资源的勘探与潜在资源量的估算提供参考。     

舟山岱山水道西部海床冲淤演变分析

根据1979,1996和2009年3个时期水深地形数据,利用GIS软件分析了岱山水道西部潮滩、水下岸坡和深槽区2个时段的冲淤变化。结果显示:1979-1996年的17 a间,研究区大部分区域冲淤幅度-般在±1 m以内,只有深槽局部区域冲刷大于2 m;1996-2009年的13 a间,潮滩区冲淤变化与1979-1996年间类似,有±1 m冲淤变化,而水下岸坡和深槽区的冲刷幅度明显加大,水下岸坡平均冲刷幅度达2 m,深槽区平均冲刷幅度达3 m。据分析, 1996年以后,水下岸坡和深槽区冲刷幅度明显加大的主要原因有两个:-是岱山水道水流流速较快,粘土质的底质容易遭受冲刷;另-个是在潮滩区至水下岸坡间建设了码头和栈桥,浅水区水流部分受阻,导致深水区域流速加大,从而加剧了水下岸坡和深槽区域的冲刷幅度。     

漳州港码头岸线规划潮流及泥沙问题研究

本文在实测资料的基础上，全面分析了漳州港海域的波浪要素，潮流动力，泥沙运移特性和水深演变等，计算了漳州港码头工程前后潮流分布场，并在此基础上预报了漳州港起步工程的３．５万吨级码头泊位、港池、航道的泥沙冲淤幅度。结果表明，漳州港海域的水深维护主要与上游纳潮面积大小有关，海域潮差大，潮流强，水深大，波浪小，海域泥沙主要来源于上游的九龙江，年输沙量为２７７万ｔ，海域年平均含沙量也不大，港池航道水深可由水流动力来维持、泊位和淤积很小，这些情况表明，漳州港屿仔尾海区建港的自然条件是优越的。     

Deposition of hydrogenetic and hydrothermal manganese minerals in the Ogasawara (Bonin) Arc Area,Northwest Pacific

A widespread distribution of hydrothermal and hydrogenetic manganese deposits is described in the results of the Hakurei‐Maru cruises conducted in the Bonin Arc areas of the West Pacific from 1984 to 1989. Manganese deposits occur in the active volcano chains, back‐arc basins, remnant back‐arc ridges, and oceanic seamounts.

The hydrogenetic iron‐manganese deposits commonly form earthly black crusts and nodules on the topographic highs of inactive ridges and old seamounts, sometimes as thick as 10 cm. They are always composed of the iron‐manganese mineral vernadite. Co and Ni contents are relatively high in the crusts from the seamounts in the open Pacific Ocean (up to 1.1% Co and 1.0% Ni). Two generations of distinct chemistry and texture are typical of these crusts, which can be compared to reported thick crusts from the Central Pacific seamounts.

The hydrothermal deposits, characterized by dense, submetallic, and gray appearance, are dominant in the recent and also in past submarine volcanoes of the island‐arc systems. Evidence of past hydrothermal activity was ascertained as fossil hydrothermal manganese deposits inside the hydrogenetic nodules or beneath the hydrogenetic crusts over the Tertiary island arc. Their component minerals are considered to be todorokite and bimessite (stable and contractible upon dehydration), having almost negligible amounts of Fe, Si, Al, Ni, Co, Zn, Pb, Cu, etc. In the small model site, the Kaikata Seamount hydrothermal area, the presumably recent hydrothermal activity has yielded thin slabs of pure manganate deposits growing downward within volcanic and sand layers.

Early diagenetic influence is negligible on nodules of this area.     

基于BP神经网络的西北太平洋柔鱼资源丰度时空变化研究

西北太平洋柔鱼(Ommastrephes bartramii)是我国鱿钓船队重要捕捞对象,其资源分布的时空变化对资源的可持续开发和利用有重要影响。本文以2000−2015年7−10月西北太平洋柔鱼渔业数据的单位捕捞努力量渔获量作为应变量,以年份、月份、经度、纬度、海表面温度、海表盐度、海面高度、叶绿素a浓度作为自变量,构建BP神经网络模型,推测该段时间西北太平洋柔鱼丰度时空变化规律,并探究环境因子对柔鱼资源丰度的影响。通过比较,确定输入层为年份、月份、经度、纬度、海表面温度和海表盐度,隐含层神经元数量为8的模型均方误差最小,模型最优。结果表明,单位捕捞努力量渔获量年间波动明显,每年的7月、10月柔鱼资源丰度较低,且空间分布分散在整个作业渔场,8月、9月资源丰度较高,并集中在41.5°～43.5°N, 155°～160°E局部区域。研究认为,海表面温度和海表盐度对柔鱼资源丰度时空变动有较大影响,在今后柔鱼资源评估与管理中予以考虑。