Impacts of Soil.Water Conservation in Jialing River on Sedimentation of the Three Gorges Reservoir

The Jialing River is one of the main tributaries of the Yangtze River. The average annual runoff accounts for 16 % and the sediment load 26% of the total at Yichang therefore it＇s one of the main contributors of sediment to the Three Gorges Reservoir. Ever since 1989, our country has implemented ＂Yangtze River soil and water conservation＂ project, Till the end of 1996, altogether 25.8 % of erosion area in Jialing River has been improved after large scale conservation has taken effect. The analysis and comparison between records taken before and after the implementation of soil and water conservation on runoff and sediment yield indicated that the sediment load soil erosion in Jialing river basin has been taken under control to some extent. Amount of annual runoff in main conservations have generally dropped by exponential function. Obvious result has been achieved in Jialing River, efficiency of sand reduction is about 10%-25%. Therefore, sediment to Three Gorges Reservoir is decreased accordingly, and it will be beneficial to take advantage of reser- voir＇s synthetic benefit.     

浅谈长江上游经济带的地位和作用

在经济全球化的条件下,区域经济一体化是全面推进工业化与城市化进程的必然选择.谁能在区域经济一体化的发展进程中占有先机,谁就能在经济全球化的竞争中获胜.在此背景下,准确把握长江上游经济带的地位和作用显得尤为重要.本文通过对长江上游经济带特征的分析,从全国生产力布局、西部大开发战略和长江流域经济开发三个方面对长江上游经济带的地位和作用进行了论述.     

Abnormal high pressure in Kuqa foreland thrust belt of Tarim basin: Origin and impacts on hydrocarbon accumulation

Following analyses of the abnormal high pressure distribution characteristics, based on the geological characteristics, tectonic stress field and physical simulation, we investigated the formation mechanisms of abnormal high pressure and its impacts on hydrocarbon accumulation in the Kuqa foreland thrust belt. The abnormal high pressure appears at the bottom of the Paleogene and obviously exists in the Triassic and Jurassic. However, the pressure coefficient in the Triassic and Jurassic is lower than that in the Cretaceous and at the bottom of the Paleogene. Horizontally, the abnormal high pressure distribution is characterized by E-W orientation zoning. The maximum pressure coefficient lies in the Kelasu-Dongqiu-Dina tectonic zones in the center of the Kuqa foreland thrust belt and decreases away from the tectonic zones. The formation of abnormal high pressure was mainly related with the intense tectonic compression in the Early Pleistocene time, and tectonic uplifting, undercompaction and hydrocarbon generation were secondary factors contributing to abnormal high pressure. Under the rapid and intense tectonic compression in the Early Pleistocene, the rock framework firstly undertook 1/4 of the compression stress and the other was borne by the pore fluids. Due to the presence of great seal of gypsum-salt or gypsum-mudstone beds in the Paleogene, the pressure of pore fluids increased rapidly and led to the abnormal high pressure in the Kuqa foreland thrust belt. The abnormal high pressure has important impacts on hydrocarbon accumulation. It is one of the necessary conditions for formation of large oil and gas fields in the Kuqa foreland thrust belt.     

舞阳河特大桥预制箱拱吊装设计和安装

考虑舞阳河特大桥由于桥梁高、跨径大、河水深及环境保护等因素,原设计主拱圈支架现浇施工方案难以实施,经多方共同研究决定采用分段预制主拱圈箱拱吊装,统筹考虑全桥的施工场地及施工进度计划,主要介绍缆索吊装设备及缆索吊装系统、缆索吊装的施工工艺等内容.     

黄河流域水生态的现状及防治对策

结合黄河流域水生态的现状,分析了影响当今水生态环境问题的自然和人为因素,提出了保护黄河流域水生态环境的对策。     

黄河断流成因与对策研究

从地球科学“人为地质作用理论”出发 ,分析了黄河下游断流的严重性与危害性后认为 ,黄河下游断流不仅对黄河流域及整个中国生态环境产生重大影响 ,而且对社会经济发展以及可持续发展产生严重后果。在探讨了黄河下游断流的成因后认为 ,黄河下游断流有自然的原因和人为的原因 ,其中人类活动、人类工程活动及其人为地质作用的负面影响是黄河断流最主要的原因之一 ,从而提出解决黄河下游断流的科学对策 ,包括科学保护、科学开发、科学利用水资源以及暂缓实施南水北调中、西线工程等的若干建议     

琼东南盆地第三纪高分辨率层序地层划分特征

通过对南海北部琼东南盆地第三纪地震、测井曲线和岩相资料的3综合分析，进行了高分辨率层序地层划分。盆地充填序列按古构造运动面划分为5个超层序，分别与盆地演化的阶段性相当。在其内部可进一步划分为19个Ⅲ级层序和42个Ⅳ级层序。并以基准面旋回为基础，长周期基准面旋回为周期，短周期为成因地层单元，论述了不同结构和叠加样式的短期旋回型式及在中长期旋回中的分布规律，基准面变化与层序发育特征、层序分布模式、沉积体系类型和盆地充填演化序列，以及与油气储盖组合的关系。     

广东封开河儿口盆地的古地理环境初探

渔涝河的上游干流—七星河长 4 2km ,在中更新世中期至晚期形成。峒中岩、黄岩洞和罗沙岩等洞穴的动物群化石测龄 14 8～ 2 2 4kaBP ,时间跨度约 13万a而该化石堆积层的厚度仅 1m余 ,且与七星河的第一级阶地类高 ,反映晚更新世早期至中期该盆地底部的构造升降基本上稳定。这是同期广东许多河谷地段没有构造抬升的一个重要信息 ,而且可将今日广东第一阶地沉积的最老年龄从目前已知的 5 1 9kaBP推延伸到 15 0kaBP。     

汾河下游三万年来沉积环境演化

根据汾河下游岩性特征、沉积物粒度、粘土矿物和孢粉分析，探讨了汾河下游3万年来环境演化规律。30－11Ka.B.P为晚更新世末次冰期盛冰期，气修干寒；11Ka以来，经历了3个气候旋回，变化周期为3.5Ka左右，黄河中游早期文明起源及人类生产活动，与本区气候关系有很好的耦合性。     

长江流域进口铁矿石水运系统研究

分布于长江流域的钢铁企业，每年需要从国外进口大量的铁矿石，这部分铁矿石进口的水运过程需要跨越远洋，沿海和内河3个不同的航,不及航线，中转方式以及船型等众多不确定因素，为了求解这样一个复杂的水运大系统，对这些钢铁企业钢铁矿石原料的进口需求进行了分析和预测，建立了长江流域进口铁矿石水运网络模型，利用运筹学和最优系统规划的方法，以1年内进口铁矿石运输的总费用为目标函数，对水运网络中各条航线的运量分配，航段划分，运输方式和运输船舶的选择等系统要素进行整体综合优化，并对运输线路和，运输船型，航线运时等进行了全面规划。