浅淡长江江西段堤岸的治理与保护

从分析江西长江堤防建设的历史过程出发，探讨了长江堤岸存在的洪涝灾害、岸线崩塌、人为影响等问题，并提出了治理、保护长江堤岸的几项措施。     

江河水位升降对堤岸边坡稳定性的影响

针对洪水期江河堤岸溃堤,溃坝问题、研究了水位变化对堤岸边坡稳定性的影响,考虑堤岸体的透水性和地下水浸润造成堤岸体软等因素的影响,通过数值计算,初步论证了因堤岸体中潜水位变化的滞后引起的快速退水的危害性质,同时发现了不管是退水还是涨水,都存在一个使堤岸边坡的稳定系数最小的水位值。这一结论对堤岸边坡的设计和防护具有指导意义。     

水道堤岸复合体的沉积构型研究

水道堤岸复合体是深海区域重要的沉积单元,同时也是深水油气勘探的重要储层类型。水道堤岸复合体的研究有利于揭示该深水沉积单元的沉积构型特征。本文利用高分辨率三维地震资料和测井资料,结合区域地质资料和地震正演模拟技术,对水道堤岸的复合体的外部形态、内部结构、物理属性及其演化进行了研究。研究表明：1）水道堤岸复合体外部形态呈＂海鸥＂翼状,由＂U＂形或＂V＂形水道和楔形堤岸组成,其堤岸又可以分为内堤岸和外堤岸两部分;2）堤岸沉积的岩性主要受重力流的岩性影响,堤岸岩性由内向外逐渐变细。而相应的水道充填沉积物的岩性则比较复杂,可能与重力流的岩性、持续时间以及海平面升降等因素有关。水道堤岸复合体沉积构型的研究为深水储层预测及评价提供理论依据,可以提高储层预测精度。     

广州国际生物岛生态型堤岸工程建设

以广州国际生物岛堤岸工程为例,介绍了生态堤岸包括防洪、保护岸坡的稳定性,同时具有生态、景观、旅游等多层次的功能,探讨了生态堤岸设计的原则及工程设计及施工的细节和特点。     

水利水电工程中堤防护岸工程施工技术分析

水利水电工程中的堤岸防护施工技术是保证堤岸坚固，从而提高水利水电工程质量的重要措施。堤岸防护工程要针对堤岸存在的实际问题，分析具体原因，并提出有效的解决措施。水利工程的堤防护岸施工技术关系着水利工程的安全及其作用的发挥，必须高度重视。     

长江中游下荆江段漫滩系统土壤氮空间分布特征研究

【目的】对比研究河段尺度土地利用方式与水文地貌单元不同组合模式下土壤氮分布的差异性。【方法】选取长江中游下荆江段7种典型组合模式下的15个样地,0~20cm土层每隔5cm环刀采样,然后测定土壤的全氮含量及容重,并计算土壤氮密度和储量。【结果】0~20cm土层的土壤全氮含量及氮储量在芦苇地中较在薏杨林地中高,且在江心洲人工芦苇地中最大,在堤岸薏杨林地最小。不同地貌单元0~20cm土壤全氮含量及氮储量的对比则是同为芦苇地以在江心洲最高,然后依次是河漫滩、堤岸;同为薏杨林地以在故道中最高,然后依次是河漫滩、堤岸。在土壤全氮含量及氮密度的垂向分布上,农林活动增强了0~10cm土层土壤氮的相对富集、加大了垂向变异,江心洲人工芦苇地的垂向分布特征体现了大洪水间歇期土壤氮的阶段性累积过程,不同组合模式下土壤氮的差异性在0~10cm土层较大、10~20cm土层较小。【结论】河流漫滩系统土壤氮不仅受到土地利用的影响,还与水文地貌性质如洪水脉冲、侵蚀与堆积特性等有关。     

长江中游下荆江段漫滩系统土壤氮空间分布特征研究

【目的】对比研究河段尺度土地利用方式与水文地貌单元不同组合模式下土壤氮分布的差异性。【方法】选取长江中游下荆江段7种典型组合模式下的15个样地,0~20cm 土层每隔5cm环刀采样,然后测定土壤的全氮含量及容重,并计算土壤氮密度和储量。【结果】0~20cm土层的土壤全氮含量及氮储量在芦苇地中较在薏杨林地中高,且在江心洲人工芦苇地中最大,在堤岸薏杨林地最小。不同地貌单元 0~20cm土壤全氮含量及氮储量的对比则是同为芦苇地以在江心洲最高, 然后依次是河漫滩、堤岸;同为薏杨林地以在故道中最高,然后依次是河漫滩、堤岸。在土壤全氮含量及氮密度的垂向分布上,农林活动增强了0~10cm土层土壤氮的相对富集、加大了垂向变异,江心洲人工芦苇地的垂向分布特征体现了大洪水间歇期土壤氮的阶段性累积过程,不同组合模式下土壤氮的差异性在0~10cm 土层较大、>10~20cm土层较小。【结论】河流漫滩系统土壤氮不仅受到土地利用的影响, 还与水文地貌性质如洪水脉冲、 侵蚀与堆积特性等有关。
     

河流冲刷作用下人工堤岸稳定性研究

针对河流冲刷造成堤岸坡脚及坡面缺损的情况建立了将冲刷预测和边坡稳定分析相结合的耦合分析方法。首先基于实测资料建立人工神经网络预测模型,对冲刷作用下堤岸及河床的变形进行预测分析,以获得堤岸坡脚被冲刷后的几何形态,然后在此基础上对边坡进行稳定分析和应力-应变分析,得出被冲刷后的边坡的整体稳定评价和变形特征。通过北江大堤某河段典型断面的计算,验证了所建立的模型和所采用的方法的有效性,对于人工堤防的运行管理具有理论意义和重要的实用价值。     

大直径盾构切穿抗滑桩对堤岸的变形影响分析

为研究大直径盾构切穿护岸抗滑桩对堤岸的扰动影响,确保盾构隧道穿越过程中大堤的安全性与稳定性,采用有限元分析软件建立了隧道-桩基-堤岸三维数值模型,重点分析了盾构切穿施工时堤岸及桩体的变形规律,并对比了不同盾构推力下桩体的变形差异.研究结果表明:盾构切削护岸抗滑桩将导致大堤迎水面边坡产生较大扰动,坡顶出现最大纵向位移,被切桩周围土体出现明显下沉;在盾构推力以及迎水面滑坡推力的双重影响下,抗滑桩以挠曲变形为主,整体形成一条倾斜的“S”形曲线,盾构刀盘抵近桩体时的抗滑桩挠曲变形最为明显;盾构推力由0.7倍静止土压力增至0.9倍,桩身水平位移大幅增加,盾构刀盘抵近桩基时的桩底位移增幅高达162%.综上可知,盾构切削穿越抗滑桩时应严格控制推进速度、泥水压力等施工参数,以减小盾构推力对堤岸及桩体的不利影响.     

堤岸防护中抛石护脚施工方法

本文主要介绍了水上水下抛石在堤岸防护中的施工方法和质量控制。     

长江中游洪灾的历史地理考察

从历史地理角度考察，长江中游洪灾是其他形水系缺陷，流域环境恶化，堤防修筑草率共同作用的结果，与历史时期相比，现代大型水库一定程度上弥补了其地形水系的缺陷，但与此同时，流域生态环境进一步恶化，堤防抗洪能力依然薄弱，人类环境管理失败所致的流域生态环境恶化依然是长江中游洪灾的根本原因，实施流域综合治理战略是减轻长江中游洪灾的必然选择。     

鲁西岩墙群侵位机制的磁组构研究

在华北克拉通东部鲁西地区广泛发育大规模的中元古代基性岩墙群, 侵位于早前寒武纪结晶基底内, 以近南北走向为主。通过岩墙群的岩石和地球化学特征分析, 认为鲁西地区岩墙群属于轻稀土略富集型, 岩墙群的岩浆源自富集型地幔, 形成于大陆裂谷环境。岩墙群的构造形态和流动构造表明鲁西基性岩墙群是基性岩浆侵位到先存的张性破裂中的产物, 岩墙自北部向南部侵入。磁组构的最大长轴方向与岩墙中线的夹角指示岩墙流动方向为自北向南, 进一步说明鲁西岩墙群是向南侵位的。另外, 结合鲁西岩墙群与燕辽拗拉谷的时空关系分析, 鲁西岩墙群很可能是来自中元古代燕辽-中条拗拉谷底部富集地幔型岩浆从北向南侵位到先存破裂中形成的。     

Magma flow inferred from magnetic fabrics in Wanning gabbro pluton and diabase dykes, Hainan

Measurements of anisotropy of magnetic susceptibility (AMS) were performed on a gabbro pluton and 7 diabase dykes in the Wanning area, southeast Hainan Island. Rock magnetism showed that pseudo-single domain (PSD) to multidomain (MD) Ti-poor magnetite carries the magnetic fabric in the gabbro pluton whereas MD Ti-poor magnetite carries the magnetic fabric in the diabase dykes. The corrected anisotropy degree (Pj ) in most specimens was found to be less than 1.2 which is indicative of a possible flow-related magnetic fabric. The AMS eigenvectors within each site are generally well grouped. The maximum susceptibility axes (K1 ) of the gabbro pluton are inclined towards the north at low angles (< 30°). K1 axes of the diabase dykes are inclined towards the NNW and SSE with dip angles of ≤ 30°. From this study, it appears that the emplacement mode of the gabbro pluton was characterized by intrusion from the north to the south at a low angle whereas the diabase dykes were emplaced from the NNW to the SSE at low to moderate angles. This was verified by comparison of the rock fabric to the magnetic fabric. All of this evidence leads to the conclusion that the Wanning gabbro pluton and diabase dykes were the products of pulsative intrusion from the same magma chamber in the area far to the north of Wanning, which suggests that basic rocks may exist beneath the Indosin- ian granite in the area to the north of Wanning.     

广西沿海红树林养护海堤的生态模式及其效益评估

传统维护海堤的模式周期性地破坏红树林、红树林滩涂及光滩的沉积物，加剧台风暴潮时海堤的险情。从围垦地取土方加固海堤，堤外滩涂便于红树林的恢复和营造，在堤内挖掘形成的养殖沟可发展半咸淡水养殖。这种生态维护模式极大地增强了海堤抗台风暴潮的功能，产生的效益比传统模式的高１０倍。生态维护模式的规模是恢复红树林５９．２４ｋｍ，面积５２９．４ｈｍ２；营造红树林３９４．６ｋｍ，面积３９４５．８ｈｍ２；养殖４５３．８４ｋｍ，面积２２６．９２ｈｍ２。对生态养护模式建设中的一些管理问题提出建议。     

Age of Bangong Lake SSZ ophiolite constraints the time of the Bangong Lake－Nujiang Neo-Tethys

The Bangong Lake ophiolite is located in the westernmost part of the Bangong Lake-Nujiang River suture zone. It is a tectonic mélange consisting of numerous individual blocks of peridotite, pillowed and massive lavas and mafic dykes with SSZ-type ophiolitic geochemical affinity formed at the end of a Wilson circle. The SHRIMP U-Pb ages of the co-magmatic zircon domains from one gabbroic dyke (Sample 01Y-155) range from 162.5±8.6 Ma to 177.1±1.4 Ma with an average of 167.0±1.4 Ma (n = 12, MSWD = 1.2), suggesting that the subduction of the Bangong Lake Neo-Tethyan Ocean started before the Middle Jurassic. It is inferred that the tectonic transform from spreading to subduction of the Neo-Tethyan Ocean began before the Middle Jurassic in the Bangong Lake area.     

Inconsistent correlation of seismic layer 2a and lava layer thickness in oceanic crust

At mid-ocean ridges with fast to intermediate spreading rates, the upper section of oceanic crust is composed of lavas overlying a sheeted dyke complex. These units are formed by dykes intruding into rocks overlying a magma chamber, with lavas erupting at the ocean floor. Seismic reflection data acquired over young oceanic crust commonly image a reflector known as 'layer 2A', which is typically interpreted as defining the geologic boundary between lavas and dykes. An alternative hypothesis is that the reflector is associated with an alteration boundary within the lava unit. Many studies have used mapped variability in layer 2A thickness to make inferences regarding the geology of the oceanic crust, including volcanic construction, dyke intrusion and faulting. However, there has been no link between the geologic and seismological structure of oceanic crust except at a few deep drill holes. Here we show that, although the layer 2A reflector is imaged near the top of the sheeted dyke complex at fast-spreading crust located adjacent to the Hess Deep rift, it is imaged significantly above the sheeted dykes section at intermediate-spreading crust located near the Blanco transform fault. Although the lavas and underlying transition zone thicknesses differ by about a factor of two, the shallow seismic structure is remarkably similar at the two locations. This implies that seismic layer 2A cannot be used reliably to map the boundary between lavas and dykes in young oceanic crust. Instead we argue that the seismic layer 2A reflector corresponds to an alteration boundary that can be located either within the lava section or near the top of the sheeted dyke complex of oceanic crust.     

华北克拉通中元古代岩墙群形成的构造应力场数值模拟

华北克拉通中部广泛发育中元古代镁铁质岩墙群。这些岩墙群未变形和未变质,侵位于先存破裂中,成为恢复华北克拉通中部中元古代构造应力场的显著标志。克拉通北部地块的镁铁质岩墙群为张剪性,而中部和南部地块为张性。根据华北克拉通中部中元古代镁铁质岩墙群的分布和成因机制分析,来恢复模拟中元古代的构造应力场。数值模拟结果表明镁铁质岩墙群在中元古代形成于伸展的大地构造背景,与横穿华北克拉通中部的燕辽-中条拗拉槽系的伸展作用有一定的联系。     

模袋砂堤防沉降量预测的分数阶灰色模型

为获得更优的模袋砂堤防沉降预测结果,基于灰色模型,提出一种分数阶灰色模型。运用MATLAB语言编写了相关程序,实现微分阶次到分数阶的改变,并运用该模型对模袋砂滩涂围垦测试的沉降结果进行实例分析。分数阶灰色模型与灰色Verhulst模型、残差GM模型、GM(1,1)模型对比分析表明:(a)分数阶灰色模型预测结果更精确,其不仅具有GM(1,1)模型前期预测效果好的优点,而且具有灰色Verhulst模型后期预测效果好的优点;(b)分数阶灰色模型的中长期预测结果稳定性比残差GM模型好。     

解决泉州港口淤积问题的探讨

本文分析了泉州港的泥沙来源,淤积原因和水深变化的情况,提出了治理淤积问题的途径,并研究其可行性。     

Epitaxy of rare earth element fluorcarbonate minerals from carbonatite dyke at Bayan Obo, Inner Mongolia, China

Rare earth element fluorocarbonate minerals such as bastnaesite and parisite are firstly discovered in carbonatite dykes from Bayan Obo, Inner Mongolia, China. Bastnaesite rarely occurs as homogeneously single crystal, but contains microfine phase of parisite. They form regular intergrowth along (0001) plane net, which is identified as epitaxy. This eptactic texture results from the variation of chemical composition of crystallizing agents of those minerals that crystallize directly from carbonatite magma.