南海双峰盆地的形成演化及其对构造样式的约束

南海北部深水区已逐渐成为我国南海北部油气资源调查的热点区域,开展南海北部双峰盆地构造样式及成因分析研究对进一步认识南海北部沉积盆地的形成演化和评价油气资源潜力具有重要的借鉴意义。利用广州海洋地质调查局已有的二维地震资料,在对双峰盆地地震层序和构造精细解释的基础上,厘定了双峰盆地主要的构造样式;采用平衡剖面技术,重建了双峰盆地的构造演化史;结合南海北部区域构造背景,分析了双峰盆地的性质和成因。研究认为,双峰盆地为与洋壳热沉降有关的坳陷沉积盆地。从神狐运动开始,双峰盆地经历了大陆破裂—大陆裂解—海底扩张完整的构造演化旋回,在持续伸展构造应力场的作用下,形成了双峰盆地,主要发育伸展构造样式、转换-伸展构造样式、重力滑动构造样式和火成构造样式4类,其中伸展构造和火成构造较为发育。     

黄河三角洲潮间带大型底栖无脊椎动物群落结构与分布特征

为了解黄河三角洲潮间带大型底栖无脊椎动物现状,于2019年5月分别对建国后黄河入海口4个流路区域20个潮间带站位进行了采样调查.调查共采集到大型底栖无脊椎动物5纲16目37科60种,主要优势种有托氏（虫昌）螺(Umbonium costatum)、泥螺(Bullacta exarata)、光滑河篮蛤(Potamocor...     

Efficiency analysis of open trench for impact pile driving through a single-variable method

Abstract

The ground vibrations during pile driving operation have a drastic potential to undermine the surrounding structures both in land and reclaimed land. Particularly, reclaimed land necessitates ample application of pile driving due to the weak land condition. To prevent the structural damage, attenuation of the ground vibrations to an allowable level through active isolation of circular open trench is the scope of this study. In this research, finite element simulations of continuous impact pile driving process from the ground surface was executed with particular attention to the pile-soil interaction, and thereby, the efficiency of open trench application in attenuation of the unsafe distance of different structures was surveyed using the vibration sensitivity degree. Regarding the crucial parameters of an open trench (depth, width, and location), it was concluded that a sufficient high depth can attenuate the unsafe distance up to 68%, the trench width variations are less effective, and an average pile-trench distance is the most efficient option. The excavation volume was also concluded as another crucial parameter in open trench design which takes all three parameters into account. The trench depth equal to the pile’s maximum critical depth of vibration was inferred for an optimum design.     

Behavior of soil plugs in open‐ended model piles driven into sands

Calibration chamber tests were conducted on open‐ended model piles driven into dried siliceous sands with different soil conditions in order to clarify the effect of soil conditions on load transfer mechanism in the soil plug. The model pile used in the test series was devised so that the bearing capacity of an open‐ended pile could be measured as three components: outside shaft resistance, plug resistance, and tip resistance. Under the assumption that the unit shaft resistance due to pile‐soil plug interaction varies linearly near the pile tip, the plug resistance was estimated. The plug capacity, which was defined as the plug resistance at ultimate condition, is mainly dependent on the ambient lateral pressure and relative density. The length of wedged plug that transfers the load decreases with the decrease of relative density, but it is independent of the ambient pressure and penetration depth. Under several assumptions, the value of earth pressure coefficient in the soil plug can be calculated. It gradually reduces with increase in the longitudinal distance from the pile tip. At the bottom of the soil plug, it tends to decrease with increase in the penetration depth and relative density, and to increase with the increase of ambient pressure. This may be attributed to (1) the decrease of friction angle as a result of increase in the effective vertical stress, (2) the difference in the dilation degree of the soil plug during driving with ambient pressures, and (3) the difference in compaction degree of soil plug during driving with relative densities. Based on the test results, an empirical equation was suggested to compute the earth pressure coefficient to be used in the calculation of plug capacity using one‐dimensional analysis, and it produces proper plug capacities for all soil conditions.     

海洋中硼的研究

硼是海水中的常量元素,也是自然水体中重要的生物、地质、化学元素。海洋中的硼含量、Ｂ／Ｃｌ 比常用于指示水团,研究大洋环流。海洋粘土中的硼含量作为古盐度的指标。硼也对海洋浮游生物的生长起重要的作用。本文综述了海洋中硼的研究,讨论了海洋中硼的迁移。     

正韵律厚油层剩余油的水平井开发技术研究

与直井相比,水平井开发具有缩短油井井距,扩大泄油面积,提高临界锥流量,更好地控制注入流体、改善波及效率等优势。在相同采液量的情况下,水平井可以降低采液强度,减缓含水上升速度。特高含水期河流相储集层的顶部是剩余油富集区,利用水平井技术挖掘正韵律厚油层顶部剩余油,取得了很好的开发效果,最终采收率较直井开发提高了14个百分点。     

九龙江口水体中1995年有机物的转移

1995年3个航次调查研究结果表明,九龙江口水体总有机物的含量受悬浮物含量控制。在S＜5的低盐度区,悬浮泥沙和有机物产生明显的絮凝沉降;在S＞5的广阔海域,它们的迁移接近于理想混合。估算得出九龙江河流的入海通量约：悬浮泥沙为9．8×105t／a;总COD为3．2×104t／a,其中溶解态COD为2.1×104t／a,约占2／3,为水体有机物的主要形态,如换算为溶解有机碳,则DOC的平均通量为3．2×104t／a。     

CC区多金属结核分布特征及其与地质地理环境因素之间的关系

根据１９８７、１９８８、１９９０年东北赤道太平洋ＣＣ区的３个航次多金属结核调查资料的统计分析，结果表明，ＣＣ区自西向东，从北向南，多金属结核丰度，覆盖率、形态、粒径和化学组分等具明显的区域分布规律，但在这一区域性分布背景上，结核的局部分布很复杂。     

Elastic response of catamaran wetdeck to liquid impact

The impact of an elastic plate onto the compressible fluid without free surface deformation is considered. The ability of the liquid volume to be deformed is geometrically limited which leads to severe impact conditions. The present analysis is focused on the stresses in the plate and the hydrodynamic loads under the impact. The motivation for this research comes from ship hydrodynamics, where the hulls of a catamaran restrict the liquid outflow and the water impacts onto the wetdeck. The influence of the air on the impact process is investigated. The analysis did not reveal any great advantage of utilizing the air-cushion effect or ejection of air into the water near the impact region to prevent high stresses in the elastic plate. It was found that in the problem considered, the stress peaks far from the plate centre and the one-mode approximation does not provide correct information about the stress level.     

Estimating the underwater light field from remote sensing of ocean color

We present a new approach that incorporates two models to estimate the underwater light field from remote sensing of ocean color. The first employs a series of analytical, semi-analytical, and empirical algorithms to retrieve the spectrum of inherent optical properties (IOPs), including the absorption and the backscatter coefficients, from the spectrum of remote sensing reflectance. The second model computes the profile of photosynthetically available radiation E _0,PAR (z) for a vertically homogeneous water column using the information of the retrieved IOPs and the ambient optical environment. This computation is based on an improved look-up table technology that possesses high accuracy, comparable with the full solution of the radiative transfer equation, and meets the computational requirement of remote sensing application. This new approach was validated by in situ measurements and an extensive model-to-model comparison with a wide range of IOPs. We successfully mapped the compensation depth by applying this new approach to process the SeaWiFS imagery. This research suggests that E _0,PAR (z) can be obtained routinely from ocean-color data and may have significant implications for the estimation of global heat and carbon budget.