珠海海积软土剪切带微观结构试验研究

天然软土剪切带性状分析一直是岩土力学界的一个研究重点。采用电镜扫描和压汞法对珠海海积软土剪切带内外以及带边缘微观结构进行定量分析,研究结果表明：珠海软土的应力-应变曲线在低围压下表现出明显应变软化特征;软土在剪切破坏后,剪切带内的微观参数变化率最大,其次是剪切带边缘,最后是剪切带外;剪切带边缘上的颗粒逐渐沿着剪切应力的方向呈定向排列,而剪切带内,由于颗粒发生破碎、折断,颗粒排列是随机的,在剪切带外,颗粒的排列受剪切破坏的影响较小;珠海海积软土的孔隙入口孔径分布为主单峰分布,其主峰峰值的位置是沿着剪切带外--带边缘--剪切带内转移;Roscoe理论和Arthur经验公式预测的剪切带倾角与实测值相比都偏小,不适宜黏性土的剪切带倾角预测计算;Mohr-Coulomb理论计算出的倾角与实测值比较一致。     

深圳地区吹填淤泥的工程特征

以深圳南油“３１４”吹淤造陆地区为例，系统分析了吹填淤泥土的物质组成，微观结构特征及其物理力学特征，认为吹填泥土属现代人工堆积淤泥质超软土，具有高含水量，高孔隙比，高压缩性，低承载力的物理力学特征，其物质组成及微观结构与海淤泥有很大差别，在进行造陆加固方案设计时，必须考虑其特殊的工程特征。     

冻结作用对青藏红黏土及兰州粉土微观结构的影响分析

冻土微观孔隙特征是决定冻土体一系列物理、力学性质的基本参数,冻土中存在的冰晶体其体积受温度影响发生变化会影响到冻土的土体微观结构及孔隙特质发生变化。利用可用于负温冻土观测的新型扫描电镜,通过对青藏红黏土及兰州粉土不同初始条件下的土样冻结前后微观结构进行研究分析。结果表明：冻结作用发生后,冰晶生长对周围土颗粒产生挤压作用,导致周围土颗粒的移动和结构破坏,土中大孔隙的数量增多,加之周围小孔隙补给大孔隙中的冰晶进一步生长,出现局部个别大孔隙体积增大,小孔隙体积缩小的现象,表现在孔隙率上为土体在冻结后孔隙率减小;此外,对于粒径级配不同的土体而言,冻结作用对细颗粒土的土体孔隙的尺寸、形态以及排列方式等方面的影响均大于粗颗粒土;同样,初始含水率决定了冻结作用发生后参与改变土体微观结构的冰晶体生长的"量"的大小,在冻结作用对土体结构性破坏的过程中起重要作用。研究成果定量揭示了冻结作用对不同初始条件下的土体微观结构的影响,为研究冻土宏观力学特性和冻胀机制等提供了理论基础与和试验支撑。     

Regional variation in exhumation and strain rate of the high-pressure Sambagawa metamorphic rocks in central Shikoku, south-west Japan

Regional variation in the P–T path of the Sambagawa metamorphic rocks, central Shikoku, Japan has been inferred from compositional zoning of metamorphic amphibole. Rocks constituting the northern part (Saruta River area) exhibit a hairpin type P–T path, where winchite/actinolite grew at the prograde stage, the peak metamorphism was recorded by the growth of barroisite to hornblende and sodic amphibole to winchite/actinolite grew at the retrograde stage. In the southern part (Asemi River area), rocks exhibit a clockwise type P–T path, where barroisite to hornblende core is rimmed by winchite to actinolite. The difference in P–T path could suggest a faster exhumation rate (i.e. more rapid decompression) in the southern than in the northern part. On the other hand, physical conditions of deformation during the exhumation stage have been independently inferred from microstructures in deformed quartz. Recrystallized quartz grains in rocks from the low‐grade (chlorite and garnet) zones are much more stretched in the southern part (aspect ratio ≥ 4.0) than in the northern part (aspect ratio< 4.0), indicating a higher strain rate in the former than in the latter. These facts may indicate that the exhumation and strain rates are correlated (i.e. the exhumation rate increases with increasing the strain rate). The difference in the exhumation rate inferred from amphibole zoning between the northern and southern parts could be explained by an extensional model involving normal faulting, where the lower plate can be exhumed faster than the upper plate due to the displacement along the fault. Furthermore, the model may explain the positive correlation between the exhumation and strain rates, because the lower plate tended to support more stress than the upper plate.     

含煤地层封堵抑制型钻井液添加剂的研究

含煤地层,裂隙发育且复杂多变,在钻进过程中事故频发。针对这一现象,首先从含煤地层微观形貌分析入手,发现含煤地层存在大量微裂缝,且裂缝中多为水敏膨胀型充填物,易导致含煤地层失稳。采用降低钻井液滤失、封堵抑制水分侵入含煤地层的思路,通过理论与实验相结合的方法,优选出具有增黏兼降滤失作用的高聚物黄原胶XC,能封堵地层孔隙的超细惰性材料纳米二氧化硅、超细碳酸钙3种添加剂。通过室内实验分别测试出了加入不同剂量（质量分数）添加剂对钻井液的流变、滤失性能等参数,将实验数据整理分析,发现钻井液的性能参数随这3种添加剂剂量变化的规律。通过膨胀实验佐证了XC聚合物钻井液体系的抑制效果,并从微观结构的角度阐述了这3种添加剂的作用机制。研究成果对含煤地层的钻进提供了理论依据,同时在类似含煤地层的钻进中具有一定的参考价值。     

黏性土力学强度与微结构动态环境能场内在关联分析

通过两组不同含水率的黏性土分别在快浸、慢浸、冻融、不同应力条件下的试验,讨论了黏性土力学强度特性与其微结构动态环境能场的本质关联,分析研究了黏性土微结构动态环境能场、外部环境条件变化与其内在介质环境变化之间的密切关联。结果表明,水的浸入对土的微结构特性影响至关重要,对土的抗剪强度的影响明显高于土的变形特性,偏湿土和受振动的土击数越多,对土的初始结构损伤越厉害,但土的后期结构强度有所提高。分析表明冻融对土的微结构破坏最为严重,其次是慢浸。     

Comparative study of microstructural characteristics and stored energy of mechanically activated hematite in different grinding environments

Hematite concentrate was mechanically treated using different milling machines and experimental conditions in air atmosphere. The changes in phase constitution, particles size, specific surface area, lattice parameters and X-ray amorphous phase fraction of activated hematite were determined. It was found that the agglomeration of the particles take place during extended milling with accessible pores for Nitrogen gas. The higher media surface brought about the largest specific surface area whatever milling devices used. After 9 h of grinding with higher media surface, the maximum and minimum specific surface area resulted from the grinding in the tumbling and vibratory mills, accounting for 6.83 m²/g and 18.42 m²/g, respectively. For the same grinding condition, tumbling mill produced the lowest X-ray amorphous phase. The maximum X-ray amorphous material estimated around 85% from the grinding in the planetary mill with higher media surface for 9 h of milling.     

油气田开发中构造地质成因分析进展

构造地质成因分析,在油气田开发中具有十分重要的作用。文章从国内外研究现状入手,在文献调研基础上详细对 比了油气田开发中构造地质成因分析的优缺点。总结了构造地质成因分析研究内容：（1） 通过构造演化历史分析和地应力 场等研究,确定断裂体系构造地质成因。（2） 井震结合开展精细的构造解释,分析构造地质成因。（3） 对构造地质成因研 究方法进行探索和改进。（4） 综合动静态资料,开展储层地质成因分析。（5） 与沉积相研究和成岩作用研究等紧密结合。 （6） 加强地质成因分析成果应用,为油气田开发提供基础。（7） 裂缝表征和建模。（8） 微构造地质成因分析。油气田开发 中构造地质成因分析的方法主要包括：基础地质研究、野外露头观察描述、岩心观察和描述、镜下薄片观察、物理模拟、 各种测井解释、地震解释、各种分析测试统计、地质建模、动态监测和生产动态分析方法等。结合研究实践,对每一种方 法的优缺点进行分析。在此基础上,指出了油气田开发中构造地质成因分析存在的8方面主要问题和发展趋势。     

前寒武纪干酪根微结构的高分辨电镜研究

本文根据高分辨电镜观察结果,描述了若干前寒武纪干酪根的微结构,讨论了干酪根微结构与母岩变质作用的关系。发现,在变生和变质过程中,干酪根微结构的变化趋势是不同的;层间距(d_(002))不是H/C比值的线性函数;干酪根的微结构可以指示母岩的变质程度。