电厂港池取水工程泥沙回淤研究

运用半封闭港区水域泥沙回淤研究结果，以及电厂港池取水物理模型试验结果，提出电厂港池取水回淤计算模式。应用此模式对某港拟建电厂各取水工况进行港池航道回淤计算分析。     

核电厂取水明渠泥沙回淤分析

核电厂需用大量冷却水,用水量为工业用水的第一位。明渠取水是核电厂常用的取水方式之一。本文针对电厂取水明渠及口门外水流特点,分析计算了取水明渠内各部位及口门外过渡段的泥沙回淤率,并提出减少明渠泥沙回淤量的措施。     

近海航槽的回淤率计算

本文应用粘性细颗粒泥沙近年实验成果,对近海动力条件进行适当概化,由输沙连续方程导得以悬沙落淤为主的航槽回淤率计算关系式.通过连云港、赤湾港等航道港池实测资料验证,说明本文提出的计算模式可用来预报近海航槽的回淤率.     

青草沙水库工程对附近水域河床冲淤的影响

青草沙水库是长江河口的一个重大工程,显著改变了北港上段的河势。河势的变化会引起流场和泥沙质量浓度的变化,进而影响河床的冲淤。本文应用三维水动力和泥沙数值模式,计算和分析了青草沙水库工程对附近水域流场、泥沙质量浓度和冲淤的影响。青草沙水库工程建设后,北港河道束窄,导致水库北侧河道主槽流速和泥沙质量浓度增加。水库工程使得进入北港的径流量和纳潮量减少,导致青草沙水库以东、北港下段和拦门沙区域流速和泥沙质量浓度下降。应用半理论半经验河床冲淤公式和模式计算的工程前后流速、泥沙质量浓度和水位数据,给出了由水库工程造成的河床冲淤变化分布。在水库以北北港水域发生普遍冲刷,冲刷强度最大可达2~3 m,冲淤分布和量值与工程前后实测水深变化吻合良好。数值模式较好地模拟了青草沙水库工程对附近水域冲淤分布的影响和变化量值。     

渤海湾南港工业区港池航道回淤研究

天津南港工业区位于渤海湾典型的淤泥质海岸,其港区为环抱式有掩护的平面布局,规划建设10万吨级航道。为准确预测港池航道的泥沙回淤状况,采用双向嵌套网格建立波浪潮流共同作用下的泥沙运动数学模型,考虑波浪辐射应力作用,以及波浪引起的紊动和波浪增强海床底部切应力对悬沙输移的影响。模型选取现场实测大潮作为代表潮,以工程海域附近测波资料的能量加权平均结果作为代表波,对邻近的天津港15万吨级航道年均回淤进行了验证,确定数学模型中相关泥沙运动与底床冲淤的计算参数。在此基础上,数学模型预测了南港工业区规划的港池航道总的年均回淤量,与天津港主航道资料类比,计算的南港工业区港区10万吨级航道泥沙回淤分布与淤积总量是合理的。     

淤泥质海岸围垦促淤计算方法研究与应用

海岸围垦工程实施后,将会改变地形及边界条件,并对工程区的水动力及泥沙冲淤产生影响。针对淤泥质海岸的特点,选取适当的经验参数,在平面二维潮流的基础上应用半经验半理论的泥沙冲淤计算方法,并考虑波浪对沉降机率和水流挟沙能力的影响,建立了淤泥质海岸围垦促淤的计算方法。同时,以舟山市钓梁围垦二期工程作为实例进行分析,利用工程区实测水文泥沙资料,确定当地挟沙能力公式参数,并对区内进行冲淤计算,得到冲淤强度的分布,通过实测资料的对比,取得了满意的结果。其中,考虑波浪效应后的计算结果更符合实测资料,波浪对该围垦工程促淤效果的影响比例在0.76%~17.5%之间,不能忽略。     

围海工程对邻近港区泥沙回淤的影响研究—以漳州港招商局中银码头区为例

针对港区附近围海造地造成的港区泥沙回淤量增大问题，以漳州港招商局中银码头区为例，全面分析了漳州港海域的地形地貌、水动力特征、泥沙特性和岸滩自然演变。根据工程建设前后地形变化，结合岸线回填量和九龙江输沙资料，分析了围海造地对岸滩演变及港区码头回淤的影响。研究表明，围海工程实施后，邻近港区的泥沙回淤由自然回淤、滩地抬高和回填引起的浑水回淤三部分组成。当围海工程结束，新岸滩调整达平衡后，泊位及港池的回淤将逐渐降至正常自然回淤强度。     

潮流泥沙数学模型在青岛港挡沙堤工程的应用

考虑波浪辐射应力对潮流场和泥沙运动的影响,建立了青岛港前湾三期码头前沿挡沙堤工程二维潮流泥沙数学模型。在采用实测资料验证的基础上,运用模型对本海域在无挡沙堤及不同挡沙堤长的各种方案的流场变化和泥沙回淤情况进行计算研究。结果表明,无挡沙堤时,由于三期工程的建设缩窄了河口至海区的断面面积,断面西侧的浅水区水流速度增大,容易掀起泥沙输移至断面东侧开挖后的深水区,使泥沙在码头前港池中落淤,码头前沿最大淤积强度约为0.818 m/day;而建设挡沙堤后将显著减小码头前沿的泥沙淤积。经过比较,从挡沙堤附近流场与港池航道回淤情况的角度考虑,认为方案二对码头前沿拦沙的效果较好。     

港池泥沙回淤过程的估算

本文利用作者曾提出的一种理论模式和计算方法,根据泥质弱潮河口的特点对顺岸码头港池泥沙回淤过程问题进行了初步的分析研究,并以汕头渔港“冷库”港池为例,解释了估算的步骤,其结果还得到了实测资料的初步验证。     

日照港煤码头浚深工程回淤分析

采用水动力学三维数学模型对日照港煤码头水域的水动力因素进行了计算,并在此基础上对煤码头浚深工程实施后港池和航道回淤进行了计算分析.计算结果与实测结果比较表明:文中模型较好地重演日照港煤码头水域潮流场,对于港池与航道的回淤分析合理可靠.     

黄河口海域沉积速率的研究

本文根据黄河口海域的特点,提出了一个新的模式描述沉积过程。将岩芯分成几个较大的部份,每一部份都代表一种沉积环境。在一种沉积环境中,输沙量虽有波动,但这种波动是有周期性的。在不同的周期中,可以认为。~(210)Pb的沉积通量是恒定的。计算不同层段之间的沉积时间可以采用公式: 由于输沙量的周期性变化,沉积物的含水量也往往呈现有规律的周期性变化。文中求出了各岩芯含水量W与。~(210)Pb含量之间的回归方程式,发现相关系数普遍较高。     

往复海流作用下桩基局部冲刷及海底沉积物粒度变化

根据胶州湾海湾大桥现场试桩结果,对海流作用下桩基局部冲刷进行了研究。通过对桩柱附近实测海流以及试桩前后桩柱周边海底沉积物粒度变化联合分析,发现桩柱竖立后,桩柱根部优势流迎流面发生局部冲刷,侧面和背流面发生局部淤积。桩柱附近海底沉积物粗化,且根部优势流迎流面海底沉积物粗化最为明显。说明桩柱竖立后,细颗粒物质迁移,使桩柱附近海底发生冲淤变化。     

Physical properties of the shallow sediments in late Pleistocene formations,Ursa Basin,Gulf of Mexico,and their implications for generation and preservation of shallow overpressures

Understanding the evolution of abnormally high fluid pressures within sedimentary formations is critical for analysing hydrogeological processes and assessing drilling risks. We have constructed a two-dimensional basin model and have performed numerical simulations to increase the understanding of the history of fluid flow and shallow overpressures in the Pleistocene and Holocene formations in the Ursa basin, deepwater Gulf of Mexico. We measured physical properties of sediments, such as porosity and permeability, in the laboratory and estimated in situ pore pressures from preconsolidation pressures. We obtained porosity–effective stress relationships from measurements of bulk density, grain density and preconsolidation pressures in the laboratory. Porosity–effective stress relationships were also obtained from downhole density logs and measured pore pressures. The porosity–effective stress and porosity–permeability relationships obtained were applied in two-dimensional basin simulations. Results showed that high pore pressures developed shortly after sediment deposition. Peaks in pore pressure ratios were related to high sedimentation rates of mass transport deposits and the incision of the Ursa channel. Lateral flows from the area where the overburden is thick towards the area where it is thin have occurred at least since 30 ka. Present pore pressure and temperature distributions suggest that lateral flows play a role in re-distributing heat in the basin.     

The Côte d’Ivoire–Ghana transform margin: sedimentary and tectonic structure from multichannel seismic data

We present multi channel seismic data recorded at the transition between the Ivorian (rifted) basin and the Côte d’Ivoire–Ghana marginal ridge (formed in a Cretaceous transform margin). The ridge is made of sedimentary sequences continuous with the synrift sediments of the Ivorian basin. Clinoformal structures suggest synrift progradational sedimentation originating from the Brazilian craton, which was located to the south during the Cretaceous. Subsequent to rifting, southward migration of the transform motion isolated the ridge from the Brazilian shelf. In the western part of the marginal ridge, crustal half-grabens are buried by postrifting progradational sedimentation, suggesting important posttransform subsidence.     

Sedimentation rates and heavy metal pollution of sediments in the Seto Inland Sea

In the Suo-Nada area of the Seto Inland Sea, Japan, sedimentation rates and the sedimentary record of anthropogenic metal loads were determined by combining the Pb-210 dating technique with heavy metal analysis of the sediments. The sedimentation rates vary from 0.11 to 0.27 g cm^–2 yr^–1. Lower sedimentation rates were observed in the eastern part of the basin which is characterized by a bottom with sand and gravel, and fast tidal currents.Anthropogenic and natural loads of copper and zinc into the sediments are 34 and 326, and 65 and 375 ton yr^–1, respectively. The anthropogenic loads are fairly low compared with those of the other main areas of sediment accumulation in the Seto Inland Sea. The highest level of zinc and copper pollution was observed in the western part of the basin because of waste discharge from an old and big ironworks outside basin since the early 1900's.     

山东龙口港口区表层沉积物的粒度分析

通过对龙口港航道附近小范围内表层沉积物的粒度分析,探讨该港口航道附近的表层沉积物的类型和分布特征。结果表明：1）研究海域的表层沉积物类型分为砂、粉砂质砂、砂质粉砂和粘土质粉砂4种。2）研究海域的表层沉积物主体是砂,其主要变化趋势是由岸到海砂的质量分数逐渐减小又逐渐增大。从它们平面分布来看,粉砂粒组与砂粒组含量的平面分布特征正好相反,粘土含量的平面分布特征与粉砂相似。3）研究海域表层沉积物的平均粒径为2．14～12．79Φ,平均为7．7Φ,沉积物颗粒的直径总体上为细砂粒径;分选系数为0．55～2．99,平均为1．82,分选差;偏态为一0．10～O．75,平均为o．20;峰态为0．63～2．76,平均为1．01。     

北黄海盆地与朝鲜安州盆地和中国胶莱盆地的对比

北黄海盆地位于黄海北部,是我国油气地质与勘探开发研究相对最为薄弱的海域,在研究的3个盆地中,北黄海盆地系海域含油气盆地,面积5万km^2,迄今我国尚未钻井;朝鲜安州盆地系跨海陆域盆地,面积最小,但是钻井最多;中国胶莱盆地则为最邻近北黄海盆地的陆域沉积盆地,目前有少量钻井,并是胜利油田外围勘探盆地。在前人研究基础上,利用后两者钻井地质与野外剖面调查的测试研究成果,初步对比了3个沉积盆地地层岩性沉积与含油气性的特征。     

Modern sedimentation rates in the intertidal zone on the west coast of the Bohai Gulf

On the basis of the measurement of ^210Pbcx and ^137Cs activities in the sediment cores taken from the intertidal zone on the west coast of the Bohai Gulf, the average sedimentation rates of modern sediments are calculated. The results indicate that in the sandy area of the intertidal zone (from Daogouzi to the Duliujian River), the sedimentation rate from 1955 to 1963 is 3.43～4.06 cm/a, and is within the range of 0.65～1.59 cm/a since 1963. The average sedimentation rate in the muddy area (around Qikou) is approximately 1.81 cm/a.The results above suggest that the sandy area of the intertidal zone has experienced rapid sedimentation from the 1950s to the 1960s,and the sedimentation slows down after the 1960s, and the sedimentation rates increase from north to south spatially. The rapid sedimentation from the 1950s to the 1960s in the sandy area is due to the fact that North China has plentiful precipitation during this period and the intertidal zone is supplied with abundant matter sources for sedimentation. After the 1960s, the weakened sedimentation may be a result of the reduction of sand transported to the intertidal zone, which is a consequence of diminished rainfall in North China and intensive human activities in the Haihe basin.     

琼东南盆地断裂构造与成因机制

琼东南盆地断裂较为发育,主要发育NE、近EW和NW向的三组断裂,其中NE向和近EW向断裂是主要的控盆断裂。盆地早期发育主要受基底先存断裂的控制,形成了众多裂陷构造;晚期主要受热沉降作用控制,断裂不太发育,对沉积的控制作用较弱,从而使盆地具有典型的裂陷盆地和双层结构特征。琼东南盆地受到太平洋俯冲后撤、印藏碰撞和南海张开等多期构造的作用,盆地的裂陷期可以分为两阶段:始新世—早渐新世的整体强张裂期,晚渐新世—早中新世的弱张裂期。     

福建九龙江和东屿地区全新世微型硅藻的初步研究

利用透射电镜研究了九龙江口现代潮间带表层沉积物、九龙江地区中全新世剖面和东屿中-晚全新世剖面的微型硅藻(细胞大小为2～20μm)的组成和丰度.共计硅藻12属26种(包括变种).对每个种的生态分布作了描述,并提供了相应的壳面电镜照片.Thalassionema nitzschioides是九龙江口现代潮间带表层沉积物中的优势种;九龙江中全新世地层的优势种为Navicula climacospheniae,Thalassionema nitzschioides;东屿中-晚全新世地层中,Cyclotella striata,Thalassionema nitzschioides是优势种.微型硅藻在各个样品中所占比例都相对较高,最高可达86.7%,表明微型硅藻在沉积硅藻中占有重要的地位.