东海油气资源区海底稳定性评价研究

海洋灾害地质因素是影响海洋开发活动安全的重要因素。通过提取东海油气资源区的地球物理和工程地质资料中的灾害地质因素和对东海油气资源区灾害地质环境的充分研究,以灾害地质因素为评价因子,应用GIS技术,采用加权统计模型对研究区的海底稳定性进行分区定量评价。利用评价结果,确定了东海油气资源区基于地貌类型区划的海底稳定性级别。     

河北七里海外海岸沙丘群成因新探

七里海有中国第一大潟湖之称,多数学者认为七里海外的海岸沙丘群是在滨外沙坝的基础上发育形成的。研究认为,七里海外的海岸沙丘群是在末次冰期时期风成沙丘群的基础上演化形成的继承性沙丘综合体。七里海也不是科学意义上的潟湖,它没有形成海岸沙坝这一潟湖形成的过程,其前身是晚更新世末期由风暴活动形成的风蚀洼地。应加强七里海外海岸沙丘群的形成、发育类型及演化过程的研究,从多角度探究七里海外海岸沙丘群的演化机理和发育趋势。     

A method for simulating sediment incipient motion varying with time and space in an ocean model(FVCOM):development and validation

We modified the sediment incipient motion in a numerical model and evaluated the impact of this modification using a study case of the coastal area around Weihai, China. The modified and unmodified versions of the model were validated by comparing simulated and observed data of currents, waves, and suspended sediment concentrations(SSC) measured from July 25~(th) to July 26~(th), 2006. A fitted Shields diagram was introduced into the sediment model so that the critical erosional shear stress could vary with time. Thus, the simulated SSC patterns were improved to more closely reflect the observed values, so that the relative error of the variation range decreased by up to 34.5% and the relative error of simulated temporally averaged SSC decreased by up to 36%. In the modified model, the critical shear stress values of the simulated silt with a diameter of 0.035 mm and mud with a diameter of 0.004 mm varied from 0.05 to 0.13 N/m~2, and from 0.05 to 0.14 N/m~2, respectively, instead of remaining constant in the unmodified model. Besides, a method of applying spatially varying fractions of the mixed grain size sediment improved the simulated SSC distribution to fit better to the remote sensing map and reproduced the zonal area with high SSC between Heini Bay and the erosion groove in the modified model. The Relative Mean Absolute Error was reduced by between 6% and 79%, depending on the regional attributes when we used the modified method to simulate incipient sediment motion. But the modification achieved the higher accuracy in this study at a cost of computation speed decreasing by 1.52%.     

山东庙岛群岛海水入侵成因初探

本研究分析了庙岛群岛的气候、地质构造、地貌形态和地下水补给以及赋存环境,初步探讨了庙岛群岛海水入侵的成因机制和影响因素,为我国海岛海水入侵的调查与监测提供理论依据,对于海岛地质灾害的防治具有重要研究意义.     

海底地质灾害对社会经济发展影响的理论分析与普适性对策

海底地质灾害是一类对人类社会经济发展影响较大的海洋灾害。其主要通过制造资本、人力资本、自然资本和社会资本的损害而影响人类福利水平的提高。为了降低或避免海底地质灾害对人类社会经济发展产生的不利影响,沿海国家和地区应该具备合理的经济行为,超前的科学研究,科学的工程防治,普及式的防灾教育以及"四位一体"的防灾减灾体系。     

循环荷载作用下粉土的动力学特征

选用近海分布广泛的粉土为研究对象,利用动三轴压缩试验结果得到了动荷载作用下粉土的应力-应变关系、孔压发展模式及动强度与临界循环次数之间的关系;探讨固结围压和固结比对粉土动力学性质的影响。动力学试验结果表明,动剪切模量随着固结围压的增大而增大,动阻尼比随动剪应变幅的变化关系受围压影响不大;不同围压对动剪应力的比值影响很小,同一围压下随着固结比的增大,动剪应力比也会随之增大;不同围压及不同固结比对以Nf表示的峰值孔隙水压力发展模式影响很小。     

全新世大暖气广西钦州湾红树林衰退的红树林源有机质贡献示踪及其对亚洲季风的响应

The response of mangrove ecosystems to the Asian monsoon in the future global warming can be understood by reconstructing the development of mangrove forests during the Holocene climatic optimum(HCO), using proxies preserved in coastal sediments. The total organic matter in sediments of a segmented core, with calibrated age ranges between 5.6 and 7.7 cal. ka BP and corresponding to the HCO, from the Qinzhou Bay in Guangxi, China, is quantitatively partitioned into three end-members according to their sources: mangrove-derived, terrigenous,and marine phytoplanktonic, using a three-end-member model depicted by organic carbon isotope(δ13Corg) and the molar ratio of total organic carbon to total nitrogen(C/N). The percentage of mangrove-derived organic matter(MOM) contribution is used as a proxy for mangrove development. Three visible drops in MOM contribution occurred at ca. 7.3, ca. 6.9, and ca. 6.2 cal. ka BP, respectively, are recognized against a relatively stable and higher MOM contribution level, indicating that three distinct mangrove forest degradations occurred in the Qinzhou Bay during the HCO. The three mangrove forest degradations approximately correspond to the time of the strengthened/weakened Asian winter/summer monsoon. This indicates that even during a period favorable for the mangrove development, such as the HCO, climatic extremes, such as cold and dry events driven by the strengthened/weakened Asian winter/summer monsoon, can trigger the degradation of mangrove forests.     

福建东山岛地质灾害区划

近年来随着福建东山岛经济的发展,各种海岛开发工程活动和自然因素的共同作用下引发的地质灾害也呈上升趋势,威胁着岛上居民生命财产安全和海岛的生态环境.为更有效地对东山岛进行保护性的规划与开发,通过对东山岛的地质灾害的现状及分布规律的调查,在GIS技术支持下,把研究区划分为高易发区、中易发区、低易发区3类,并全面分析了地质灾害易发区的安全性及其控制机理,认为人类活动是引发地质灾害产生的主要因素之一.     

南黄海油气资源区海底沉积物的工程地质特征

根据HY126-04项目1998年9月的航次调查及随后的沉积物样品的实验室分析资料，从物理性质和力学特征各方面对南黄海海底沉积物进行了综合工程地质特征研究，发现本区沉积物结构、剪切特征、含水量和液盖子发随深度的变化而变化；本区样品主要为粒径较细的软沉积物，具有高含水量、中-高塑限、高压缩性和抗剪切强度小的物理力学特性，并对样品的物理性质和力学特征二者关系进行回归分析，得出回归方程。     

焦家断裂带深部抽水试验成井止水方法探索

焦家断裂带是我国著名的金矿聚集带,分布有新城金矿、焦家金矿、朱郭李家金矿、寺庄金矿等多个深部大型矿山,多年来围绕该带提交的详查报告很多,矿床水文地质条件研究程度较高。为了能更加确切、清晰地反映焦家断裂带下盘地下水水文地质特征,围绕抽水试验技术方法稍作改进,应用过程中效果明显。