非饱和土微观结构与粒间吸力的研究进展

吸力是非饱和土研究的重点也是其难点。重点在于自然界中诸多物理现象可以用吸力去解释，难点在于非饱和土吸力的量化测试技术现在还不成熟。非饱和土作为地球表层广泛存在的三相组合材料，其力学性质远远比饱和土复杂，归根结底在于土中水气界面形成的弯液面收缩膜，导致了土体孔隙产生吸力。非饱和土体的强度变形特征就是其内部吸力不断变化的宏观表现形式，其宏观物理力学性质与吸力之间存在一个桥梁——微观结构。对非饱和土微观结构和吸力理论、试验研究的整体把握是完善土力学的一个重要方法。开展对非饱和土液桥动态结构演化及吸力力链分布特性的研究，是全面了解非饱和土力学性能的重要基础之一，也是深入把握和量化非饱和土吸力的重要手段。     

Deep-sea coral geochemistry: Implication for the vital effect

Deep-sea corals hold a great potential as a key to important aspects of paleoceanography for at least two reasons, 1) they offer temporal high resolution records of deep-sea environment, because they have growth banding structures, 2) and they are well suited for studying vital effects, because the deep-sea environment does not change over short time scales. However, the relationship between the chemical composition of deep-sea coral skeletons and environmental factors is not well understood. In this study, the chemical composition of deep-sea corals was measured in bulk individuals and along skeletal micro-structures. Among the bulk individuals, δ¹⁸O value and Sr / Ca ratio show a negative but weak correlation with ambient temperature. On the other hand, the Mg / Ca ratio has a positive, weak correlation with the temperature. Large variations were found among samples collected from similar temperature. The variation is up to 3.8‰ for δ¹⁸O, 0.9 mmol/mol for Sr / Ca ratios, and 0.78 mmol/mol for Mg / Ca ratios among samples with ambient average temperature within 1 °C. This variation may be due to a large vital effect. The centers of calcification (COCs), which were formed at high calcification rate, have lower Sr / Ca, U / Ca and higher Mg / Ca ratios than surrounding fasciculi. This chemical distribution supports the model that elemental incorporation depends on calcification rate. This suggests that calcification rate is a very important factor for the chemical composition in deep-sea corals and is one of the most significant mechanisms of the vital effect. Because of this large vital effect, further investigations are essential to use the deep-sea coral as a temperature proxy.     

Microshear zones in a Miocene submarine dacite dome of southwest Japan

Microscopic shear zones have been found in the groundmass of glassy rocks of a Miocene submarine dacite dome in southwest Japan. Similar textures have been reported previously but only in dykes. These textures give a valuable insight into the deformation of the dome during its emplacement by recording the orientations of the principal strains. Detailed textural analysis indicates that the microshear zones formed as a result of flattening and stretching of the magma simultaneously with quenching. Measured stretching directions are near-parallel suggesting the magma flowed in one dominant direction rather than in a radial pattern. The strain is believed to also be influenced by high magma pressure inside the dome being imposed on the high viscosity outer part of the dome. Present address: Faculty of Resource Science and Management, University of New England-Northern Rivers. P. O.Box 157 Lismore NSW 2480 Australia     

黄河口饱和粉土的电性特征及其工程地质应用

通过对形成于1964年～1976年位于黄河口潮坪区粉土层样品电阻率、井中电阻率和电阻率剖面的测试,分析了土的含水率、孔隙比、饱和度、孔隙水的电阻率、颗粒成分等因素对其导电性的影响。分析结果表明：影响该地区饱和粉土导电性的主要因素为土的孔隙率。随着孔隙率的增大,其含水率升高,电阻率降低,土的电阻率和相应孔隙率的关系可用拟合公式表达。基于此,利用电阻率法成功实现了不同深度粉土沉积层微结构的变化、波浪作用导致密实度不同的粉土层空间分布状况的原位测试。     

列车长持时振动引起黄土滑坡微结构变化研究

通过研究不同试验条件下黄土滑坡滑带土孔隙定向性的变化特征,研究列车振动对黄土滑坡产生的诱发作用.结果表明:滑带黄土承受动荷载作用后,结构发生明显变化,孔隙破碎严重,其结构形态从圆形或椭圆形向长条形变化且呈一定的定向性,从而造成土体压密.在此基础之上,提出一种列车长持时振动荷载下的黄土滑坡形成机理.     

南京市冬季雾的物理化学特征

为研究南京冬季浓雾的宏微观物理结构和物理化学过程,揭示空气污染物与雾水化学结构的关系,2006—2007年冬季,在南京信息工程大学院内进行了雾的综合观测试验。观测项目包括雾的宏微观结构、雾水化学、大气气溶胶粒子谱及化学成分、辐射和热量平衡各分量、湍流以及常规气象和环境监测。在雾的生消过程中,各项目的观测是连续进行的。两年共观测到27次雾过程,并采集到37个雾水样本。按其形成,将南京冬季雾分为辐射雾、平流辐射雾和蒸发雾三类。该文详细分析了各类雾的宏微观结构,研究了强浓雾(能见度小于50m)发展的物理过程。结果指出,南京冬季雾多属暖雾,雾顶高度以平流辐射雾最高,平均顶高851m,辐射雾次之,平均顶高486m,蒸发雾偏低,平均顶高428m;各微物理参数均以平流辐射雾最大,辐射雾次之,蒸发雾最小,平流辐射雾含水量最大时可达1g/m3。通过对微物理参量连续变化分析发现,平流辐射雾和辐射雾进入强盛阶段时,都具有明显的爆发性增强特征。雾水化学分析结果表明,南京雾水离子浓度比较高,酸雾约占43%,属于硫酸型,均与空气污染物SO2、NO2和颗粒物有关。     

夯实地基土的微结构特性及其对工程性质的影响

通过对地基土强夯前后的微观结构进行研究 ,从微结构角度解释了强夯时地基土的变形破坏机理。世纪花园高饱和度地基土由于存在粘粒及集聚体 ,强夯后使土的渗透性变差 ,超孔隙压力难以快速消散 ,致使土发生变形破坏。     

孤岛油田馆陶组油层微型构造研究

通过孤岛油田油层微型构造的编制和研究，将油层顶、底面微型构造归为8种配置模式，提出在生产动态因素一定的条件下，处于双凸型和以顶凸为主的单凸型正向微型构造有利于剩余油富集；而处于双凹为主的单凹型负向微型构造不利于剩余油富集。指出沉积条件，差异压实和沉积古地形是油层微型构造的主要因素，宏观构造背景对油层微型构造类型有一定的影响。     

天台地洼型含金银铅锌矿床定位过程的研究

文中应用微结构物理类比法和成矿实验模拟法,研究了赋于中国东南地洼构造层中含金的银铅锌矿床的定位成矿过程。认为该矿床的形成,可分为两个过程,即大气降水活化、萃取地洼火山岩系中成矿元素的非定位过程和热液爆破角砾化系统定位成矿过程。显示出这类矿床具有:成矿热液是由隐伏深成岩对下渗大气降水的加热,流体源于岩浆水及大气水;近南向高角度断裂制约的双循环体系,以及成矿作用双机制(矿源层中活化、萃取机制和热液爆破沸腾沉淀机制)等特点的多因复成矿床。     

泡沫泥浆泥饼的特性研究

对泡沫泥浆泥进行了大量微观结构分析，揭示出泡沫泥饼具有粘弹性，疏水性等特性，对泡沫泥浆防塌护壁机理进行了论证。