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91.
AbstractWith the large-scale development and utilization of ocean resources and space, it is inevitable to encounter existing submarine facilities in pile driving areas, which necessitates a safety assessment. In this article, by referring to a wharf renovation project as a reference, the surrounding soil response and buried pipe deformation during pile driving in a near-shore submarine environment are investigated by three-dimensional (3D) numerical models that consider the pore water effect. Numerical studies are carried out in two different series: one is a case of a single pile focusing on the effect of the minimum plane distance of the pile–pipe, and the other is a case of double piles focusing on the effect of the pile spacing. 相似文献
92.
本文使用1960—1980年春季的水文资料,以温度和盐度作为主要指标,根据聚类分析逼近温盐图解,结合对该海域地理环境特征的分析,对烟台、威海及石岛近海春季的水团结构演变及其和渔场、渔期的关系进行综合分析。结果表明,北黄海及青岛外海的冷水团,以及黄海暖水团的强度与位置的变动,对春季渔期的早迟以及渔场位置的变动,都有很大的影响。 相似文献
93.
现代黄河三角洲粉土触变性研究及其应用 总被引:5,自引:0,他引:5
通过对现代黄河三角洲砂质粉土和粉质粘土触变性的对比试验研究,阐述了黄河口粉土的触变性。试验结果对解释粉土的失稳机制、解决工程地基的稳定性和防止地质灾害等具有重要的现实意义。 相似文献
94.
山东全新世滨海软土与工程地质灾害的研究 总被引:2,自引:0,他引:2
吴建政 《海洋地质与第四纪地质》1995,15(3):43-54
山东全新世滨海软土分布在海湾、泻湖、河口区,厚度1-10m。海湾、泻湖软土为淤泥、淤泥质土,陆源物质供应丰富的浅水区,软土颗粒偏粗,强度相对较高,触变性对建筑物危害性大,陆源物质供应少的深水区,软土颗粒偏细,低强度、高压缩性、沉降变形大和蠕变性是危及建筑物稳定的主要因素。海湾、泻湖软土位于地下水位下,具低透水性,掩埋后短期不易排水固结,软土下为强度较高的冲积物,对一般建筑物,利用强夯、粉喷搅拌桩、 相似文献
95.
Most of the existing relevant materials have been obtained from experiments, in which evaluating the added mass at the resonant frequency corresponding to the peak of a frequency-response curve obtained from the “forced” vibration analysis is the most popular technique. In this paper, a simple experimental method was presented where the “free” vibration responses instead of the “forced” ones were used to determine the values of mah and Iap. The main part of the experimental system is composed of a floating body (model) and a spring–shaft shaker. The “free” vibration of this main part was induced by imposing on it an initial displacement (and/or an initial velocity), and from the time histories of displacements information such as the “damped” natural frequencies, damping ratios, sectional added mass coefficients (CV and CP) were obtained. Since the displacements of the spring–shaft shaker are “translational” and those of the floating body due to pitch motions are “angular”, a technique for the transformation between the associated parameters of the two components of the main part was presented. 相似文献
96.
97.
Long-term variability in the intermediate layer of the eastern Japan Basin has been investigated to understand the variability
of water mass formation in the East Sea. The simultaneous decrease of temperature at shallower depths and oxygen increasing
at deeper depths in the intermediate layer took place in the late 1960’s and the mid-1980’s. Records of winter sea surface
temperatures and air temperatures showed that there were cold winters that persisted for several years during those periods.
Therefore, it was assumed that a large amount of newly-formed water was supplied to the intermediate layer during those cold
winters. Close analysis suggests that the formation of the Upper Portion of Proper Water occurred in the late 1960’s and the
Central Water in the mid-1980’s. 相似文献
98.
1Introduction TheIndianCentralWater (ICW) ,formedandsubductedintheSubtropicalConvergenceintheSouthIndianOcean ,occupiesasignificantportionofthethermoclineintheIndianOcean[1,2 ] (Fig .1 ) .TheSubantarcticModeWater(SAMW)isformedinthe 2 6.5-2 7.1σθrangenorthoftheSub antarcticFront—thesouthernboundaryofthesubtropicalgyres[3] .InthesoutheastIndianO cean ,theSAMWisthethickest,ventilatedasathicklayerofhighoxygenextendingtothetropicalIndianOcean[4 ,5 ] . Watermasstransformation… 相似文献
99.
A comprehensive numerical study on the three-dimensional structure of a turbulent jet in crossflow is performed. The jet-to-crossflow velocity ratio (R) varies in the range of 2 - 16; both vertical jets and inclined jets without excess streamwise momentum are considered. The numerical results of the Standard two-equation k-ε model show that the turbulent structure can be broadly categorised according to the jet-to-crossflow velocity ratio. For strong to moderate jet discharges, i.e. R> 4, the jet is characterized by a longitudinal transition through a bent-over phase during which the jet becomes almost parallel with the main freestream, to a sectional vortex-pair flow with double concentration maxima; the computed flow details and scalar mixing characteristics can be described by self-similar relations beyond a dimensionless distance of around 20-60. The similarity coefficients are only weakly dependent on R. The cross-section scalar field is kidney-shaped and bifurcated, vvith distinct double concentr 相似文献
100.
种植盐地碱蓬修复滨海盐渍土效果的研究 总被引:25,自引:0,他引:25
利用盐生植物——盐地碱蓬进行天津河口滨海盐碱地的生物修复。通过比较种植盐地碱蓬土壤和对照土壤的电导率、有机质和微生物数量的差异等研究了其修复效果。结果表明,种植区碱蓬根际土壤的电导率与对照土壤相比下降了13%;有机质和总氮与对照土壤相比分别增加43%和18%;根际土壤的微生物数量明显增加,放线菌和真菌分别比对照增加了5倍和16倍。根际微生物优势种群的盐耐受性结果显示,部分根际土壤的优势种群的盐耐受性明显下降,耐盐性较低的微生物种群已成为优势种群。以上结果表明,种植盐地碱蓬对改善滨海盐碱地的生态有明显的效果。 相似文献