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根据莱州湾沉积物的实验室分析资料,从物理性质和力学性质特征对海底沉积物的工程地质特征进行了综合研究,结果显示:研究区沉积物主要为淤泥质黏土,其次为淤泥、黏土、粉土,另含有极少量的粉砂,整体呈现为含水量低、天然密度大、孔隙比小、可塑性低、压缩性低、剪切强度高、贯入阻力大。从海底地形、物质来源、水动力特征、物质组成等方面对沉积物的工程特性进行了成因分析。莱州湾地势平坦,水体与外海交换能力差,沉积物的分布受地形和水动力特征的影响显著,淤泥主要出现于黄河入海口南北侧海域,黏土、粉土主要出现于莱州浅滩附近海域,粉砂分布于刁龙咀北部近岸海域,其他区域以淤泥质黏土分布为主。莱州湾沉积物主要来源于黄河携带的黄土高原物质,碳酸盐含量高,黏粒和亲水性黏土矿物含量较低,沉积物主要以胶结物和粉粒级碎屑的形式存在,导致湾内沉积物含水量低、天然密度大、塑性低、强度高。 相似文献
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海底峡谷是陆源沉积物向深海运移的主要通道,也是陆架/陆坡区重要的地貌单元。随着多波束测深技术的发展,如何快速而准确地从海量数据中识别并提取海底峡谷的特征要素,是一个亟待解决的重要热点问题。文中根据海底峡谷谷底下切、谷壁高而陡等地形特征,基于水文分析法和坡度分析等原理,通过ArcGIS中的数据建模工具建立了一种从数字高程模型(DEM)数据快速识别和提取海底峡谷特征要素的方法。以南海北部陆坡神狐峡谷区为例进行算例分析,结果表明,该方法在快速了解海底峡谷的发育位置和特征要素等方面是可行的,并可以获得峡谷头尾部水深、轴线长度、峡谷范围等特征信息。为获得该方法适用于研究区的最优参数组,文中讨论分析了峡谷形态、重分类阈值及数据分辨率等影响峡谷识别的因素。结果分析表明,峡谷形态会在一定程度上影响识别结果的准确性,但不影响对峡谷的总体了解;零值汇流累积量重分类阈值和DEM数据的空间分辨率是影响峡谷识别结果准确度的两个重要因素,在神狐峡谷群区,空间分辨率200 m且重分类阈值0.4时,海底峡谷识别和特征要素提取效果最佳。 相似文献
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The upper part of the continental slope in the northern South China Sea is prone to submarine landslide disasters,especially in submarine canyons. This work studies borehole sediments, discusses geotechnical properties of sediments, and evaluates sediment stability in the study area. The results show that sediment shear strength increases with increasing depth, with good linear correlation. Variations in shear strength of sediments with burial depth have a significantly greater rate of change in the canyon head and middle part than those in the canyon bottom. For sediments at the same burial depth, shear strength gradually increased and then decreased from the head to the bottom of the canyon, and has no obvious correlation with the slope angle of the sampling site. Under static conditions, the critical equilibrium slope angle of the sediments in the middle part of the canyon is 10° to 12°, and the critical slope angle in the head and the bottom of the canyon is 7°. The results indicate that potential landslide hazard areas are mainly distributed in distinct spots or narrow strips on the canyon walls where there are high slope angles. 相似文献
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浙闽近岸与南黄海中部沉积物物理力学性质的差异性分析 总被引：1，自引：0，他引：1
本文对浙闽近岸和南黄海中部泥质区沉积物的物理力学性质，分别从基本物理性质、水理性质及力学性质进行对比分析，发现两个区域沉积物均以淤泥为主，含水率与密度、压缩系数与压缩模量均呈良好的幂函数负相关性，液限与塑限呈良好的幂函数正相关性，含水率与孔隙比呈较好的线性正相关，十字板剪切强度与微型贯入阻力呈较好的多项式函数关系。总体来说，南黄海中部泥质区沉积物相对于浙闽近岸泥质区沉积物具有含水率高、孔隙比大、密度小、塑性高，压缩性大，抗剪强度低等特征。从地形特征、物质来源、水动力条件、沉积速率和物质组成等方面进行两个区域沉积物物理力学性质差异性的成因分析。结果显示，与浙闽近岸相比，南黄海中部离陆较远、地势低洼、水动力条件较弱，能够扩散至此的物质较少并以极细的粘粒物质为主，沉积物中的蒙脱石和有机质含量高。这些因素使得南黄海中部沉积物的含水率高，塑性大，密度低，强度低。 相似文献
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通过无人机和滩面高程监测等技术手段，获取了1909号台风“利奇马”过境山东省海阳市前后的海滩监测数据，分析海滩在台风前后的整体形态和剖面冲淤变化，探讨了海滩演化对台风的响应规律。结果表明，台风过境后海滩整体形态以风成沙丘面积略有扩大、高?中潮带滩面发生下蚀和微地貌消失等现象为主。台风对海滩的影响以侵蚀为主，造成了约2.43×104 m3的侵蚀量，且主要发生在高潮带滩面；风成沙丘以弱淤积为主，但部分岸段发生严重冲蚀；后滨则受大风和冲越流携沙堆积后以弱淤积为主；中低潮带冲淤主要受其滩面坡度控制，表现为高坡度滩面冲蚀，低坡度滩面弱淤积，且台风过后形成多个小型水下沙坝。整体而言，台风“利奇马”对山东海阳海滩演化造成一定的影响，沉积物收支愈发亏损，进一步加重了海阳海滩的侵蚀程度。 相似文献
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现代黄河三角洲钓口叶瓣体沉积相及其沉积动力环境特征 总被引：1，自引：0，他引：1
The Huanghe River captures the Diaokou River in 1964 and forms a deltaic lobe in the subsequent 12 a. The progradational process of the Diaokou lobe is in associated with complicated evolution of riverine sheet flooding,merging, and swinging. On the basis of 11 borehole cores and 210 km high resolution seismic reflection data set,the sedimentary sequence and dynamic environment of the Diaokou lobe(one subdelta lobe of the modern Huanghe River Delta) are studied. The stratigraphy of the lobe is characterized by an upward-coarsening ternary structure and forms a progradational deltaic clinoform. Totally six seismic surfaces are identifiable in seismic profiles, bounded six seismic units(SUs). These SUs correspond to six depositional units(DUs) in the borehole cores, and among them, SUs 4–6(DUs D to F) consist of the modern Diaokou lobe. Lithological and seismic evidences indicate that the delta plain part of the Diaokou lobe is comprised primarily by fluvial lag sediments together with sediments from sidebanks, overbanks, fluvial flood plains and levees, while the delta front part is a combination of river mouth bar sands(majority) and distal bar and deltaic margin sediments(minority). As a result of the high sedimentation rate and weak hydrodynamic regime in the Huanghe River Delta, the sediments in the delta front are dominated by fine-grained materials. The grain size analysis indicates the Huanghe River hyperpycnal-concentrated flow shows the suspension, transportation and sedimentation characteristics of gravity flow, and the sediment transportation is primarily dominated by graded suspension, while uniform suspension and hydrostatic suspension are also observed in places. The strength of the hydrodynamic regime weakens gradually offshore from riverbed, river mouth bar, sidebank, distal bar subfacies to delta lateral margin and flooding plain subfacies. 相似文献
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在辽东湾北部的LH01孔岩心进行高分辨率取样的基础上,测定了沉积物中的14个地球化学指标。通过对各元素与Al2O3含量的比值、特征元素比值在岩心中的垂向变化规律的分析,结合粒度、测年和R型因子分析方法,可将岩心至上而下划分为4层,分别反映了4种沉积环境:100~889cm为全新世河口滨海现代沉积,889~1330cm为全新世中期浅海沉积,1 330~1 913cm为全新世早期海陆交互相沉积,1 913~2 455cm为晚更新世末期的陆相沉积。化学元素的变化所反映的地层特征与晚更新世以来的气候和海平面变化具有较好的对应关系。 相似文献
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