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1.
韩宗珠 《中国海洋大学学报(自然科学版)》1993,(Z1)
论述了中国岩体型石榴石橄榄岩的空间分布、岩石类型、岩石化学特征,形成机制及其构造意义。提出这类岩石形成于三叠纪早期扬子陆块与华北陆块的碰撞造山事件。 相似文献
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收集埕岛海域地区近十余年的地质勘察资料,汇总该区地质灾害的类型及其分布情况,发现该区存在着凹坑、冲沟、滑塌、泥流舌、海底穿刺、粗糙海底和埋藏古河道等地质灾害,在海域西北、中部和东南部均有分布,简要探讨形成机理,计算波浪循环荷载在海床中产生的循环应力比,以及根据标贯击数和黏粒含量建立土体的循环阻抗比,然后,计算不同风浪等级下每个钻孔1m深度处土体抗液化安全系数,采用surfer8.0软件绘制安全系数等值线图。发现抗液化性能较好的区域主要分布在海域中部三块地区,随着风浪等级增大,整个区域内液化面积也逐渐扩大,海域东南地区有少量油井和管线分布,区地质灾害发生频率较高,土体抗液化性能较差,工程设施应重视较大风浪期间土体液化对其安全性能的影响。 相似文献
3.
福建沿海暨台湾海峡地质灾害初探 总被引：7，自引：1，他引：7
本文系统全面地论述了福建沿海及台湾海峡主要地质灾害类型的分在特征，发育规律及危害情况，对地质灾害的控制因素和相互的成因联系与其对于综合防治的意义进行了初步的分析，提出以成因与域因素相结合的地质灾害类型的划分原则。 相似文献
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5.
论敦煌莫高窟的环境地质灾害 总被引：1，自引：0，他引：1
环境地质灾害是敦煌莫高窟主要的环境灾害之一，其涉及范围广，类型多、成因复杂。本文初步分析研究了莫高窟环境地质灾害作用的性质、机制和强度，并提出了科学防护的主要措施和途径。 相似文献
6.
在靠近墨西哥湾下斜坡与深海平原的交接处的阿特沃特海下谷(AT)425火山喷块区，水深约1920～1930m处的海底有Ⅱ型结构天然气水合物(甲烷-乙烷水合物)和原油。该处位于墨西哥湾下伏含盐盆地界线内清楚的构造区——东密西西比扇体(MFF)中。热成因烃类的存在证实了在东MFF深部存在活动的石油系统。MFF中天然气水合物含的C2-C5烃类气体的^13C极低，使得其与上斜坡和中斜坡其它气体明显不同。AT425处石油中的生物标志物(m／z=191及217)同样与上墨西哥湾斜坡及Smackover斜坡的原油的标志物明显不同。AT425处原油的生物标志物与具有强烈的含硅粘土流体区沉积的、可能有高等植物有机质沉积的海洋源岩一致。墨西哥湾下陷带内存在的页岩或泥岩源岩引起了诸如源岩沉积时的古地理等新问题。墨西哥湾含盐盆地下陷带南部和东部在中生代突然出现的高地可以解释AT425处产生原油和天然气的页岩或泥岩源岩产状。 相似文献
7.
《海洋地质与第四纪地质》2017,(3)
以下刚果盆地M区块Madingo组烃源岩为研究对象,通过X-射线衍射、薄片鉴定、背散射、能谱分析、主量元素及有机地化测试等技术手段,分析了烃源岩的矿物组成、古生物与岩相特征,并讨论了烃源岩有机质富集机制。结果表明:Madingo组烃源岩矿物组成以黏土矿物和硅质矿物为主,方解石和长石次之,含有少量的白云石和黄铁矿;有孔虫、放射虫等微古生物发育;根据矿物组成、古生物特征和磷酸盐含量,并结合显微岩石构造,共识别出富有孔虫细粒岩、富放射虫细粒岩、磷质细粒岩、黏土质细粒岩、长英质细粒岩和灰质细粒岩6种岩相类型。研究区Madingo组烃源岩的发育受海平面升降、上升流、古地理和古气候的控制:Madingo组共识别出3期海侵/海退旋回,海平面升降通过控制水体深度、氧化还原条件和沉积物类型,进而控制岩相和烃源岩的发育;富放射虫细粒岩、磷质细粒岩和富有孔虫细粒岩有机质含量较高,推测为两期不同规模的上升流沉积;Madingo组沉积时期,研究区发育与盐底辟活动相关的陆架内部洼陷,相对封闭的水体环境有利于有机质的保存;古气候经历了干旱气候、相对湿润气候和湿润气候3个阶段,通过控制海洋中陆源有机质输入在一定程度上影响烃源岩有机质丰度和有机质类型。 相似文献
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香港平洲组有机地球化学特征 总被引：1，自引：0，他引：1
根据香港平洲组三块地化样品的分析成果,讨论其有机质丰度、可溶有机质族组分以及生物标志化石特征,结果表明：平洲组有机质丰度较高,有机质类型主要为混合型;源岩目前处于成熟阶段,具备生成一定数量油气的能力。 相似文献
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新疆干旱区地质灾害研究 总被引：1，自引：0，他引：1
本文详尽叙述了新疆干旱区突发性较强的地震、崩塌、滑坡、泥石流灾害以及具牵延性特点的土地沙漠化、盐渍化、水土流失等为主要类型地质灾害的活动规律和时空分布特征；根据灾害强度，进行了灾害等级区域划分；结合新疆干旱区特点，提出了减轻新疆地质灾害的主要对策和措施。 相似文献
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过去海平面变化特征对认识现代海平面变化过程和预估未来情景具有重要科学和现实意义。海滩岩作为热带和亚热带地区海岸潮间带特有的沉积岩，是海岸变迁和古海平面高程的重要标志物。然而，由于存在海滩岩形成后动力条件发生变化、采用的测年方法不同以及海平面高程估算和分析误差等问题，基于海滩岩的过去海平面重建结果依然存在较大争议和不确定性。我们分析和总结了南海北部中晚全新世海滩岩重建海平面的进展，以及在海平面研究中存在的问题和潜在机遇，从海滩岩的形成年代与海滩岩形成后高程产生变化等方面进一步量化研究海滩岩重建海平面变化的不确定性。同时，通过对南海北部海南岛东部沿岸的3块原生珊瑚礁（1块大型块状滨珊瑚和2块滨珊瑚微环礁）进行高精度高程测量和铀系测年，共获得6个海平面数据，结合冰川均衡调整模型（Glacial Isostatic Adjustment,GIA）和ICE-5G模型结果，对基于海滩岩重建的南海北部中晚全新世海平面的可靠性进行比较和评估。以上不确定性分析和研究结果表明，通过年代与高程校正后，海平面重建结果准确性进一步提高。研究结果可为以其他海平面标志物重建的过去海平面的不确定性分析和可靠性分析提供... 相似文献
11.
综合分析岩体块度、抗压强度、完整系数、软化系数、结构面性态、地下水及裂隙张开度等影响岩体质量的因素，提出一种岩体质量评定方法，使青岛地铁工程岩体质量评定趋于定量化、准确化。 相似文献
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为比较准确地模拟二重孔隙介质地下水溶质运移 ,本文依据二重孔隙介质法 ,分别对孔隙岩块和裂隙介质建立相应的溶质运移模型 ,将孔隙岩块视为作用于裂隙介质的源或汇 ,对反映岩块和裂隙介质之间物质交换的耦合项进行了数学推导。应用本文方法在济南地区建立起二重孔隙介质溶质运移模型。研究结果表明 ,此方法更实际地反映出裂隙对溶质较强的传导能力和孔隙岩块对溶质较强的贮存能力 相似文献
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针对采用定值相对极限位移判定隧道围岩稳定性时存在的问题,提出了采用模糊概率理论判定隧道围岩稳定的计算方法.结合厦门翔安海底隧道工程实际,利用曲线回归和模糊概率方法对海底隧道围岩稳定性概率进行了计算分析.参考现行规范并根据海底隧道各个开挖步的变形量综合确定极限相对位移上下限,采用指数函数对海底隧道CRD1部和CRD3部的拱顶下沉收敛曲线进行了回归分析.根据回归参数及实测结果,应用模糊概率公式对隧道围岩的稳定性概率进行了计算,从而为根据某个时刻的相对位移来判断海底隧道稳定性提供了参考. 相似文献
14.
根据钻孔实测资料运用趋势面分析法研究青岛地铁沿线岩体风化规律，发现岩体各风化带界面标高及风化壳厚度呈波状起伏。指出：这主要受构造、岩性控制。岩体各风化带界面标高的变化与地表形态变化表现基本一致。 相似文献
15.
Shu-Guang Song Shu-Cai Li Li-Ping Li Qian-Qing Zhang Kai Wang Yi Zhou 《Marine Georesources & Geotechnology》2016,34(4):376-383
During tunnel excavation, the deformation of surrounding rock due to the unloading of rock mass will vary with time. However, the measured displacement of surrounding rock is only a part of the actual longitudinal deformation profile. There is a need to analyze the longitudinal deformation profile to identify the deformation state and evaluate the stability of surrounding rock mass. In the present article, the variation of pre-deformation of surrounding rock due to excavation was analyzed, and the release coefficient was obtained from the measured results. For the Qingdao subsea tunnel, the measured crown settlement of surrounding rock was analyzed using the regression analysis method, and the longitudinal deformation profile of rock mass was simulated using the numerical calculation method. Moreover, based on the conditions of the subsea tunnel, a solid-fluid coupling model test was carried out to check the reliability of the numerical calculation results. The results of the model test were consistent with the numerical calculation results. 相似文献
16.
以往的海底管道落锚撞击防护数值模拟主要为单一保护层模型,这里则针对块石+混凝土排垫复合方案建立模型并开展防护性能研究。基于ABAQUS建立有限元数值模型,模拟了落锚、海底管道、海床土体、块石层和混凝土排垫组成的复杂系统相互作用,研究了管道壁厚、内压,落锚质量和撞击速度等因素对管道应变极值和管体凹陷变形的影响。与单纯块石层保护方案相比,采用的块石+混凝土排垫方案具有更优良的防护效果。研究结果表明：在撞击点处,管道的轴向应变和环向应变均达到最大值,且随着与撞击点距离的增加沿管道轴向逐渐减小;撞击结束后,管道上仍然残留一定的塑性应变。随着管道壁厚的增加,管道的最大应变和凹陷深度也随之减小;随着内压的增加,管道上最大拉伸应变变大,而最大压缩应变和凹陷深度减小。随着落锚速度或者质量的增加,管道上最大应变和凹痕深度均变大;在相同动能情况下,管道上的最大应变和凹陷值基本相同,也表明落锚动能是影响管道变形响应的控制因素。本文研究成果可为海底管道防护方案设计提供科学依据。 相似文献
17.
Yiguo Xue Binghua Zhou Daohong Qiu Maoxin Su Chuanqi Qu Xueliang Zhang 《Marine Georesources & Geotechnology》2013,31(10):1267-1276
AbstractThe overlying rock thickness of a subsea tunnel controls its vertical line. It not only ensures the safety and stability of tunnel construction period and operation period, but also ensures the economy of subsea tunnel. In the current research, few papers give full consideration to the complex indicators of prediction the overlying rock thickness. However, in this study, a hybrid intelligent system was established to predict the overlying rock thickness of a subsea tunnel based on Qingdao Kiaochow Bay Subsea Tunnel, China. The sea depth, basic quality index of rock mass, soft soil layer thickness, permeability coefficient, and construction management level were selected as the main factors influencing the overlying rock thickness. Using the data obtained from project site exploration, objective weight factors were calculated using rough set theory, and subjective weight factors were calculated using the analytic hierarchy process. Furthermore, the combination of weights was obtained for each factor. Finally, the weight of influencing factors was incorporated into the extension model, and the overlying rock thickness of pending section was calculated. The results of overlying rock thickness prediction model are consistent with the actual value, indicating that the model has good engineering applicability and application value. 相似文献
18.
Arnold H. Bouma 《Geo-Marine Letters》1987,7(2):63-67
Terminology should facilitate communication; however, inaccuracies can lead to misunderstanding; new and revived terms normally add to the confusion. Megaturbidite is a rather common term in Europe used to identify a thick, extensive deposit from an exceptionally large mass flow. Their grain size can vary from large blocks to clay size.If the term megaturbidite is used, is should be restricted to layers that: (1) are thick compared to the host rock; (2) are laterally extensive; (3) differ in composition from the host rock; and (4) lack submarine fan geometries. They are excellent markers for stratigraphic and seismic correlations, and useful in basin analyses. 相似文献
19.
Unlike response of seismometers resting on hard rock where the seismometer case moves with the rock to high frequencies, the response of ocean bottom seismometers (OBS) can be strongly affected by the low mechanical strength of ocean sediments. The motion as measured by the seismometer will not follow the expected relationships between pressure and particle motion for different wave types. Cross coupling between horizontal and vertical motions can occur, especially when there is differential motion between water and sediment. Resonant amplification and attenuation of higher frequencies also occur. Secondary seismic arrivals are especially subject to distortion. Overall response is strongly dependent upon the mass and configuration of the OBS and the rigidity and density of the bottom material. Tests at Lopez Island, Puget Sound using both directly applied mechanical transients and seismic signals with various instrument configurations demonstrate the above effects and provide some guidance for improved designs.Hawaii Institute of Geophysics Contribution No. 1172. 相似文献
20.
The long-term integrity of CO2 storage in deep saline aquifers has become uncertain due to the unsteady character of surrounding factors, and the time-dependent nature of the aquifer's overburden load (the vertical stress imposed on the aquifer by the weight of overlying materials (rock/soil layers), which may vary over time as a result of natural incidents such landslides and earthquakes) is critical. The aim of this study is to identify the influence of overburden load variations on the long-term integrity of the CO2 storage process in deep saline aquifers. High-pressure tri-axial strength and permeability tests, along with acoustic emission (AE) and scanning electron microscopy (SEM) analyses, were conducted on Hawkesbury sandstone obtained from the Gosford basin.According to the results, the injection of CO2 into the Hawkesbury formation may dissolve aquifer rock minerals, enhancing aquifer flow performance and reducing aquifer strength. Increasing the stress applied on the aquifer causes aquifer flow ability to reduce to some extent due to pore matrix compaction. Further increase of the overburden pressure may accelerate the aquifer's flow performance due to dilation-induced pore opening. This permeability transition point occurs earlier at greater CO2 injection pressures and overlaps with the crack formation point of the aquifer rock mass. Therefore, weakening of the rock mass after the transition point can be expected. Importantly, this permeability transition point occurs at lower overburden loads after longer interaction of CO2 with the saline aquifer. This exhibits the long-term risk associated with CO2 sequestration in saline aquifers. Permeability enhancement after the transition point may also produce environmental disasters, such as sudden leakages of injected CO2 from the reservoir to surrounding fresh water aquifers (Evans et al. 2004; Little and Robert 2010), exceeding the specific rates proposed by many regulatory frameworks. Therefore, it is essential to study the long-term integrity of the sequestration process in order to develop a regulatory structure to meet the demands of deep saline sequestration projects. 相似文献