南昆线南那段红土类型划分及微观特征研究   总被引：1，自引：0，他引：1  

文江泉  王贵清 《工程地质学报》1995,3(3):35-42

本文在野外调查的基础上,根据母岩岩性和红土化作用程度对南那段红土作了初步分类,并对几种主要的红土的物质成分和微观结构特征进行了研究。  相似文献   

大青山山前活动断裂变形产物中的微观粘滑与蠕滑标志     

姚大全  汤有标 《中国地震》1995,11(3):231-238

本文通过对大青山山前活动断裂带上的变形产物进行定向采集、原态固结并进行系统微观观测，结合宏观和实验岩石学资料分析，归纳出能反映该断裂运动特性的微观粘滑与蠕滑标志，并对有关问题进行了讨论。  相似文献   

香山天景山断裂带断层泥的微观研究及工程地震评价中的意义     

张秉良  梁小华 《工程地质学报》1996,4(3):47-52

断层运动是复杂多变的, 其运动在一条巨大的断裂带上经常以区段为活动单位, 为服务于工程建设和强震的预测, 划分出活断层运动区段的必要性越来越迫切。本文通过对香山天景山断裂带断层泥的微观特征研究, 结合断裂的几何特征综合分析, 认为该断裂的中段以粘滑活动为主, 东西两段主要是蠕滑。  相似文献   

Acidic Rocks as Aggregates in Concrete: Engineering Properties,Microstructures and Petrologic Characteristics     

A. I. M. Ismail  D. Sadek Ghabrial 《Geotechnical and Geological Engineering》2009,27(4):519-528

In this research, the possibility of replacing different portions of the normally used aggregate by acidic rocks was investigated. These rock types outcrop at the northern part of Eastern Desert, southwest Ras Gharib area where large quantities of good quality acidic rocks are available their. Portland cement concrete is a composite material made up of the hydrated cement matrix, fine aggregate and coarse aggregate. The scanning electron microscope equipped with an energy dispersive X-ray analysis system (EDX) has been applied to investigate several aspects of Portland cement concrete microstructure. The topics investigated so far include the influence of aggregate composition on the development of the cement paste-aggregate interface and the formation of calcium silicate hydrate CSH/calcium silicate aluminate CSA formation. The silicate gel coated the aggregates in the concrete paste and crystallized into well defined needle like shape, cotton shape as well as euhedral to subhedral crystals of silicate/alumiante and ettringite minerals with free lime librated from the hydrolysis process. The free lime can react again with the aggregates leading to the formation of cementing materials which increase strength and durability of the concrete paste by increasing the interfacial bonds between the used aggregates.  相似文献   

应用碱性水泥外掺剂固化天津海积软土的试验研究   总被引：1，自引：0，他引：1  

王宝勋  李夕兵  杜东菊  杨爱武 《工程地质学报》2009,17(3):426-433

天津海积软土具有高含水量、低强度、高压缩性、低pH值等特征,不能直接满足工程建设需要,必须进行人工处理。在水泥土搅拌法中使用适量碱性外掺剂NaOH或Na2CO3,可以提高桩身水泥土强度和复合地基承载力,同时能节省大量水泥,降低工程费用。现场试验中将海积软土与分别掺入0.5%NaOH和0.5%Na2CO3的10%水泥就地搅拌,形成两种新型水泥土,在与原状土及20%纯水泥土进行比较后,发现碱性外掺剂可以促使生成大量针状、棒状或纤维状水化硅酸钙晶体,抑制了能产生膨胀作用的钙矾石的生成,同时,有Ca(OH)2晶体析出,它们共同构成土颗粒间和土颗粒表面的充填物和包裹物,使水泥固化土的孔隙明显减小,密度和强度得到极大提高。检测结果显示水泥土强度提高了20%以上,复合地基承载力不小于120kPa。  相似文献   

黄土震陷研究及相关问题探讨   总被引：2，自引：0，他引：2  

王强  孙军杰  王兰民 《中国地震》2012,28(4):351-359

回顾了30多年来关于黄土震陷的研究工作和成果.黄土震陷已为微结构特征、动三轴和现场爆破试验所证实,成为黄土地震工程研究领域的一项重要课题,但仍缺少典型震例,且停留在饱和土理论研究阶段.应用微结构形态学方法表征土体结构性变得困难,土力学方法将是微结构应用于震陷性研究的有效途径.震陷性判定仅是在多个参变量值区间内的确定性判定,概率性震陷预测应得到开展.震陷系数估算多是基于室内试验数据的经验公式或半经验半理论公式,并未完全解决其物理过程和力学机制问题,比如参变量多、计算繁琐和实用性差等,故应从黄土震陷的物理力学机制出发,厘清影响黄土震陷的主导因素及其表征参变量,建立具有物理力学意义的数学理论估算模型.抗震陷处理技术的关键是消除土体的震陷性,并减缓震陷时土与土工结构物的相互作用.  相似文献   

Protein diagenesis in Patella shells: Implications for amino acid racemisation dating     

《Quaternary Geochronology》2015

The inter- and intra-crystalline fractions of Patella vulgata limpets recovered from archaeological sites in Northern Spain (covering Neolithic, Mesolithic, Magdalenian, Solutrean, and Aurignacian periods) were examined for amino acid composition and racemisation over time. The calcitic apex and rim areas of the shells were found to probably be composed of similar proteins, as the D/L values and amino acids were comparable and varied in the same way with increasing age; however, the mineral structures present in these areas differed. The aragonitic intermediate part of the shell showed a distinctly different amino acid composition and mineral structure. The main protein leaching from the inter-crystalline fraction occurred within the first 6000 yr after the death of the organism. In contrast, the intra-crystalline fraction — comprised of a different protein composition than the inter-crystalline fraction — appeared to behave as a closed system for at least 34 ka, as reflected by the lack of a significant decrease in the amino acid content; however, changes in the amino acid percentages occurred during this period. The concentration of aspartic acid remained almost constant with age both in inter- and intra-crystalline proteins, and its contribution to the total amino acid content increased with age at the expense of other amino acids such as glutamic acid, serine, glycine and alanine. Temperature is thought to play a key role in the amino acid racemisation of P. vulgata and could explain why in the localities belonging to the Gravettian and Solutrean period, which formed during relatively cold conditions, D/L values were similar to those detected in shells from sites formed during the Magdalenian.  相似文献   

Study of Shaking Table Test on Dynamic Response Characteristics and Failure Mechanism of the Loess Slope   总被引：2，自引：1，他引：1  

PU Xiaowu  WANG Lanmin  WANG Ping  CHAI Shaofeng  XU Shiyang 《中国地震研究》2020,34(1):121-135

The natural loess that covers the ground surface has good stability due to its low water content. However, when violent earthquakes occur, the strong dynamic stress generated in the slope may induce landslide disasters with different sizes. In this paper, a large-scale shaking table model test is used to reveal the dynamic response and instability failure process of the loess slope. The test results show that different parts of the slope have different vibration characteristics and the first natural frequency in the model increases with the increase of the slope height. The response acceleration of different parts may change due to the coupling relationship between the spectral characteristics of input wave and the natural frequencies of different parts of slope, suggesting the characteristics of regional differential dynamic response. Under the condition of different dynamic response, stress state and boundary conditions of different parts of slope, a rapid microstructural damage, cumulative residual deformation evolution, and tension-shear coupling instability failure process may appear at the top of the slope with the strong dynamic response associated with the increase of dynamic loading intensity. The S_d values presented in this paper may reflect soil damage and slope instability and failure.  相似文献   

Microstructures of structure I and II gas hydrates from the Gulf of Mexico     

Stephan A. Klapp  Gerhard Bohrmann  Werner F. Kuhs  M. Mangir Murshed  Thomas Pape  Helmut Klein  Kirsten S. Techmer  Katja U. Heeschen  Friedrich Abegg 《Marine and Petroleum Geology》2010

Gas hydrate samples from various locations in the Gulf of Mexico (GOM) differ considerably in their microstructure. Distinct microstructure characteristics coincide with discrete crystallographic structures, gas compositions and calculated thermodynamic stabilities.  相似文献   

电镜图像在黄土结构性研究中应用的几个问题   总被引：1，自引：0，他引：1       下载免费PDF全文

袁中夏  王兰民  邓津 《地震工程学报》2005,27(2):115-121

电镜结构性图像是认识黄土结构特征,分析黄土土力学特性的重要方法。本文对不同研究目的情况下如何利用黄土电镜微结构图像的问题进行了探讨,并指出随着观察放大倍数的不同,黄土的结构性图像显示出明显的尺度效应。定义了黄土结构性的分类以避免因笼统使用“微结构”这一词所带来的指代不准确性。根据土力学研究的需要对黄土孔隙划分标准提出了新的认识,建立一套新的分类标准以便利于研究运用。最后综述了在研究中选用黄土电镜结构性图像的原则。  相似文献