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1.
多孔矿物介质对有机相变材料导热性能的影响 总被引：1，自引：0，他引：1
通过对制备的基于膨胀多孔石墨和硅藻土两种多孔矿物介质与硬脂酸丁酯有机相变材料的相变蓄热复合材料,采用调制差示扫描量热方法(MDSC)测试复合材料的导热系数,并借助层状复合材料热传导模型分析多孔矿物介质内部结构特征对复合材料的导热性能的影响,其结果表明,采用膨胀多孔石墨制备的相变蓄热复合材料具有明显的层状结构,其压制方向的导热系数更接近层状复合材料热传导模型c轴方向导热系数预测结果;采用硅藻土制备的相变蓄热复合材料的导热系数符合层状复合材料热传导模型的a-b平面方向导热系数预测结果,说明该复合材料内部结构具有非常好的连通性。多孔矿物介质对相变材料导热系数的增强效果不仅受多孔矿物介质导热系数的影响,还会受到复合材料内部结构特征的明显影响,在热传导方向上形成连通性结构有利于增强效果,而形成与热传导方向垂直的层状结构则不利于导热系数的增强,即使多孔矿物介质具有很高的导热系数。 相似文献
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目前水电站建设多采用地下厂房,地下洞室围岩的变形特性是设计和施工关注的关键问题之一。采用有限元程序,结合正交试验设计方法,考虑多因素共同变化的影响,研究了各因素对地下洞室变形特性的影响显著程度．对各因素对洞室特征部位变形影响的显著性分别进行了排序。分析结果表明：拱顶位移受岩层厚度和洞室埋深的影响程度最大,左边墙中点位移受洞室埋深和洞室高度的影响最大．右边墙中点位移主要受洞室埋深的影响最大;洞室最大位移多发生在左边墙中点附近,受岩层厚度、洞室埋深、洞室高度的影响都非常显著。绘出了各因素对洞室特征部位位移的影响趋势。 相似文献
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Chen Yuxue Gao Mingzhong Li Liping Shi Shaoshuai Zhou Zongqing Zhang Mingguang 《Geotechnical and Geological Engineering》2021,39(2):1223-1236
Aiming at the asymmetric deformation of the surrounding rock in deep tunnels, from the perspective of the mechanical environment of the rock layer, the physical characteristics of the surrounding rock and the geometric characteristics of the tunnel, five kinds of influencing factors for the asymmetric deformation of the tunnel surrounding rock were selected, and the change levels of various factors were established. Through orthogonal test methods, 25 sets of orthogonal test simulation schemes were designed to study the asymmetric deformation law of the surrounding rock of deep roadway under the combined action of various factors. Three surface displacements of the surrounding rock are used as indicators to weigh the influence of various factors on the asymmetric deformation of the surrounding rock. Through the Extreme Difference analysis and F Statistics comparison of the indicators, the dominant influencing factors affect the deformation of the surrounding rock are obtained. By studying the distribution of the maximum deformation position of the surrounding rock, we have obtained the asymmetry characteristics of the surrounding rock deformation. In addition, the simplified mechanical analysis of the key influencing factors of the deformation of the surrounding rock is given, and the distribution law of the asymmetric characteristics of the surrounding rock deformation is summarized. The above research can provide a certain theoretical reference for the asymmetric deformation control and supporting scheme design of the surrounding rock in deep roadway.
相似文献4.
本文以板块构造理论为基础,根据全球各大陆陆块和微陆块的相对亲缘性、统一性和独立性,提出晚前寒武纪末一早古生代初泛大陆解体后,整个古生代期间,全球大陆可划分为三大陆块群,即冈瓦纳大陆群、劳亚大陆群,和泛华夏大陆群。论述了三大陆块群,特别是泛华夏大陆群的形成演化及其作为独立大陆群存在的统一性。指出泛华夏大陆群的独立性和统一性表现在:①早古生代末,扬子、华夏(包括黄海一东海一南海古陆)、中朝、柴达木、塔里木、昆仑一北羌塘一昌都一印支等陆块曾一度拼贴在一起,形成统一的大陆;②晚古生代中晚期形成独立的华夏植物群区系;③晚古生代末一早中生代,泛华夏大陆群主体部分的扬子一华夏和中朝陆块向西运移楔入,导致其南北两侧古特提斯洋的同步消亡和全球泛大陆的最终形成。泛华夏大陆群的形成演化历经了晚前寒武纪末一早古生代初各陆块的裂离、割据;早古生代末的拼贴、统一;晚古生代的再次分裂和晚古生代末一早中生代与南北大陆群拼贴4个发展阶段。同时指出在东特提斯构造域内,古特提斯既表现出对原特提斯的继承性,又有新生性;中特提斯不是古特提斯的延续和发展,它是标志泛大陆裂一聚巨旋回演化中另一旋回的开始。最后讨论了显生宙地球上大陆由南聚北散到北聚南散,陆块在总体上向北漂移中旋转、裂、聚和泛大陆重组和立即又解体的可能的动力学机制,即地球内部物质向南半球运移,南半球膨胀,促使泛大陆解体。地球内部物质的南移又迫使软流层物质向北运动,驱动大陆碎块北上。蠕动的软流层中,除具有垂向环流的对流环外,还具有大小不等的水平涡旋运动。正是巨大的水平涡旋运动导致了陆块的旋转、会聚(泛大陆形成)和很快脱离涡旋体面离散(泛大陆解体)。 相似文献
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M. A. Mishkin A. M. Lennikov G. M. Vovna Z. G. Badredinov R. A. Oktyabr’skii 《Geochemistry International》2007,45(6):546-560
The bottom of the stratigraphic sequence of the Dzhugdzhur deep-seated granulite complex was determined to consist of a stratified metabasite-enderbite association. The distributions of major and trace elements indicate that the protoliths of the association were volcanic rocks of the calc-alkaline, komatiite-tholeiite, and picrite series. The model assumed for the genesis of the protolithic volcanics of the metabasite-enderbite association includes two stages. The first of them was responsible for the decompression-induced partial melting of the material of an ascending mantle plume with the derivation of melts of the komatiite-tholeiite series. During the second stage, the volcanics of the calc-alkaline series were produced by the partial melting of the metabasite crust under the effect of the heat of the ascending mantle plume. The protoliths of the metabasite-enderbite association were formed in the Early Proterozoic. 相似文献
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The current study introduces the geological subsurface cross-sections in the southern part of the Gaza Strip to show the structure of the aquifer in the area. The cross-sections give evidence of four subaquifers of the coastal aquifer in the southern part of the Gaza Strip. These cross-sections give the natural reasons for the deterioration of the groundwater in the study area. The results show presence of clay lenses that prevent the replenishment processes of the aquifer of fresh water from the rainfall and returns flow from agricultural activities. Lithological formation was evident as one of the natural causes which accelerate destroying process of the coastal aquifer. The results also show that the structure of the aquifer causes the increase of the groundwater salinity in the Gaza Strip. The cross-sections had shown the shortage of storage capacity of high quantities of fresh water in the coastal aquifer in these areas. The role of lithological formation was evident as one of the natural causes to accelerate the process of destroying the coastal aquifer. 相似文献
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粒子起电问题是解决地球磁场起源中固体地球内部电流形成问题的关键之一。通过引述电化学领域二相流起电机制,建立了有利于分析地球磁场起源的固体地球内部物质流动的双电层模型结构,即液/液界面双电层模型和液/固界面双电层模型,分析了地球外核物质流动及流动起电问题。在地球运动动力和运动定律作用下,地球外核物质的定向移动是形成地下电流、产生磁场的直接原因。研究了形成地磁场电流的一般算法及影响因素,探讨了“静电”的“动电”本质,讨论了双电层模型的适应性、起电电荷电性变化、局部气旋电流、磁异常等问题。指出固体地球内部物质起电电荷电性的改变是地磁场极性倒转主要原因。 相似文献
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在对半挖半填路堤病害及成因分析的基础上,分析了加筋路堤格栅工作机制。通过现场试验,对采用格栅加筋法处理的路堤挖填交界区域进行了原位观测,观测了路堤填土完成时路面沉降、竖向土压力及格栅变形情况。通过建立有限元分析模型,对路堤填筑完成时格栅的拉力及位移进行了分析,并对不同路面荷载和格栅刚度条件下,格栅的拉力与位移进行了计算。结果表明：路堤挖填交界处铺设格栅后,路面局部差异沉降较小。填方区域格栅底部土压力与填土自重应力相当,格栅存在有效加筋长度,在挖填交界面附近产生较大变形和拉力。上层格栅比下层格栅沉降曲线平缓,下层格栅的拉力在交界区域会陡然增大。路面荷载对格栅拉力和位移有一定影响,随埋深增加影响减小,格栅的竖向位移随着荷载增大略有增大,格栅在挖填交界面附近拉力增大。随格栅刚度增大,其拉力也增大,而位移变化很小。 相似文献
9.
为探究土工格室加筋路堤在循环荷载及静载下的各种性能,利用美国GCTS公司的USTX-2000加载装置进行加载,通过改变加筋层数、格室高度,格室焊距对土工格室加筋路堤进行一系列模型试验。对各种工况下加筋路堤极限承载力、长期循环荷载及固定振次循环荷载后极限承载力的变化进行研究。试验表明,土工格室加筋能显著提高地基极限承载力并能显著减小坡顶和坡中临界破坏时的法向累积变形,在加筋间距一定的情况下,加筋层数增加和格室高度增大均可不同程度提高极限承载力并减小临界破坏时坡顶法向累积变形,格室焊距的减小也可在一定程度提高极限承载力,格室焊距对边坡法向变形影响不大;长期循环荷载下固定间距加筋层数对路堤竖向累积沉降量影响不大,而对边坡坡顶法向累积变形有一定影响,格室高度增大和格室焊距减小均可不同程度减小路堤竖向累积沉降量和坡面法向累积变形;越靠近加载点处,路堤土压力值受加筋影响越显著,加筋提高了土体刚度和密实度,使加筋路堤土压力值较无筋路堤明显增大;对于无筋路堤,改变动载幅值和振次均导致振后极限承载力有不同程度的降低,而对于加筋路堤,当动载幅值≥30 kPa或动载振次≥1 000时,振后极限承载力均有不同程度的提高。 相似文献
10.
E. V. Verzhbitskii L. I. Lobkovskii A. F. Byakov M. V. Kononov 《Doklady Earth Sciences》2012,444(2):666-670
In order to specify the origin and evolution of the Alpha-Mendeleev and Lomonosov ridges, profiles of the bottom relief and crustal basement were made. Additionally, the coefficients characterizing the rate of subsidence of the crustal basement in different parts of the ridges for the last 25 Ma were calculated and the depth of the crustal basement prior to the beginning of subsidence in the Early Miocene was estimated. The calculation results were compared with the model of thermal subsidence of the Greenland-Iceland and Iceland-Faroe thresholds, which were also formed by plume-tectonic processes. A large dome rise of the basement was found in the central parts of the Alpha-Mendeleev and Lomonosov ridges. It was also found that the coefficients of thermal subsidence of the crustal basement in the central parts of the Alpha-Mendeleev and Lomonosov ridges are close to those for the Greenland-Iceland and Iceland-Faroe thresholds. It was shown that the depth of the crustal basement prior to the beginning of subsidence in the Early Miocene grew going outwards from the central parts of the ridges, analogous to the present-day pattern. All the information given above indicates the thermal origin of subsidence for the Alpha-Mendeleev and Lomonosov ridges starting from the Early Miocene and the substantial influence of the Arctic Plume on the genesis and evolution of these ridges. 相似文献
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Charles Naville Martine Ancel Paul Andriessen Patrice Ricarte François Roure 《Arabian Journal of Geosciences》2010,3(4):459-475
Near-critical angle and refraction studies were performed at IFP as piggyback studies during a wider programme of crustal imagery operated by WesternGeco on behalf of the Ministry of Energy of the United Arab Emirates. The main objective is to illuminate the base of the Semail Ophiolite along part of a regional transect (D1) crossing the Northern Emirates from the Gulf of Oman in the east up to the Arabian Gulf in the west. Results confirm that the sole thrust of the ophiolite has been folded during the Miocene stacking of the underlying Arabian Platform. The thickness of the ophiolite grades from zero in the core of the Masafi tectonic window, up to a maximum of 1.7 km below the axial part of a successor basin which has been preserved on top of the serpentinite west of the current exposure of the main ultramafic bodies. Apatite grains extracted from plagiogranites of the Semail ophiolite also provide evidences for an early unroofing of the gabbros and plagiogranites during the Late Cretaceous, with cooling ages of 72–76 Ma at the top of the ophiolite in the east (not far from the Fujairah coast line), which are coeval and also consistent with the occurrence of Late Cretaceous paleo-soils, rudists and paleo-reef deposits on top of serpentinized ultramafics in the west. Younger cooling ages of 20 Ma have been also found at the base of the ophiolite near Masafi, in the core of the nappe anticline, thus providing a Neogene age for the refolding of the allochthon and stacking of underlying parautochthonous platform carbonate units. These results, together with the occurrence of a thick sedimentary pile illuminated below the metamorphic sole along the north-trending, strike-profile D2 running parallel to the axis of the Masafi window, should stimulate a renewal of the exploration in the central part of the Emirate foothills, where the ophiolite thickness is currently limited, and was already drastically reduced by the end of its Late Cretaceous obduction. 相似文献
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深部咸水层封存是目前最具前景的CO2地质封存方式。本文通过调研CO2地质封存相关文献，对CO2咸水层封存选址地质评价依据进行分类，总结咸水层封存涉及的定量研究方法并探讨目前CO2地质封存中的不确定性问题。主要认识有：① CO2咸水层封存选址的地质依据可根据在评价中的作用分为两类，第一类是用于可行性评价的通用依据，第二类是用于进一步筛选优选靶区的封存适宜性和安全性指标，其中封存适宜性评价针对的是更加细致的储层特征（相较于可行性评价），而安全性评价则集中在盖层适宜性、场地地震安全性、水文地质条件、地面场地地质条件、储层盖层空间分布和构造六个方面；② 封存潜力评价方面，大范围的可行性评价可首选资料要求较低的面积法进行封存潜力评价，对小范围的优选靶区采取精度更高的容积法和包含更多封存机制的容量系数法；③ 目前CO2地质封存中的不确定性问题主要在于相同依据在不同评价方面产生的不同影响、CO2- 水- 岩反应对储集物性的影响、研究发现的特殊现象、多场耦合模拟研究不系统以及封存潜力计算中参数不确定问题。 相似文献
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地下水潜力评价是资源评价的重要内容之一。本文浅析了全国地下水资源及环境问题调查评价技术要求的地下水潜力的概念和方法,以水文地质盆地为地下水系统单元,对疏勒河流域中下游三大盆地———玉门踏实、安西敦煌和花海盆地地下水潜力进行了评价,分别分析了3个盆地地下水开采潜力、利用潜力的方向,并计算各潜力大小、潜力系数级别、潜力模数大小,为疏勒河流域盆地地下水资源的开发利用、管理和调配提供了科学依据。 相似文献
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为完善中国地质学会会员体系,建立学术和专业认可制度,大力弘扬科学精神,鼓励会员不断攀登科学技术高峰,推动地质科技进步,促进我国地质事业发展,在中国地质学会迎来百年华诞之际,根据《中国地质学会章程》精神,中国地质学会设立了会士制度。按照《中国地质学会会士工作条例（试行）》和《关于开展中国地质学会会士遴选工作的通知》规定,中国地质学会于2022年4月启动了首批会士遴选工作。经会士遴选委员会遴选和中国地质学会第40届理事会第四十一次常务理事会审议通过,窦立荣等10位科学家当选为中国地质学会会士（名单见附件）。 相似文献
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提出一种层状地基中柔性筏板-群桩共同作用分析方法,探讨筏板刚度对桩筏基础沉降的影响,并成功预测了往复荷载下桩筏基础的长期沉降。筏板刚度采用Mindlin板理论的有限单元法分析;桩-土体系的刚度矩阵中,桩顶面-桩顶面、桩顶面-土表面以及土表面-土表面的相互作用分析采用层状剪切位移法借助层状地基的Burmister位移解求得。基于层状地基中柔性筏板-群桩的沉降计算方法以及往复荷载下土体压缩模量的衰减特性得到了桩筏基础的长期沉降预测方法。与已有文献方法和离心模型试验结果的对比分析表明,柔性筏板-群桩共同作用方法得到的沉降值具有较高的精度。 相似文献
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岩心裂饼是钻探过程中特有的岩石力学现象。1958年哈斯特首先报道过岩心裂饼现象,且发现岩饼的厚度与其直径的比值随初始应力的增加而减少,其后,库克则利用钻孔岩心饼化的程度评价岩体中的初始应力状态。 相似文献
19.
铁法盆地阜新组网结河沉积 总被引：5，自引：1，他引：4
铁法盆地为晚中生代半地堑式断陷盆地,阜新组的网结河沉积发育于断裂盆缘内侧冲积扇至湖缘三角洲之间的湖退进积体系域。大量的钻孔和矿井地质资料详尽揭示了网结河道相、河岸相及湿地相的特征,其中,泥石流沉积是网结河道相的一种特殊的成因类型。在有关各成因地层单元中,以网结河沉积体系的繁盛发育为主体,以网结河沉积体系的衰退并伴随大面积泥炭沼泽化而结束。盆缘断裂活动比较活跃、盆地沉降速率大、沉积充填速率高、河道坡降小是网结河发育的重要条件。 相似文献
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基于天津于家堡南地下车库工程扩底桩抗拔极限承载力试验,结合数值模拟手段对扩底桩抗拔承载特性、破坏模式和受力机制开展了分析研究。计算分析表明,扩底桩（有效桩长19 m）相比等截面桩抗拔极限承载力提高约50%,材料增加仅8.5%,扩底桩扩大头周边土体提供的抗力显著提高了抗拔承载力;荷载较小时抗拔力主要由等截面段侧摩阻力提供,扩头段抗拔力占桩顶加载的比值随加载近似呈线性增加;扩底桩等截面段沿桩土界面先发生剪切破坏,扩头段周边土体后发生受压破坏,抗拔承载力达到极限;扩头段位于同一土层时,不同桩长扩头段提供的极限抗拔力相差不大,桩长越长,扩头段抗拔力贡献率越低;扩头段抗拔力主要由自重、扩头段法向力竖向分力和侧摩阻力组成,其中法向力竖向分量提供了扩头段的主要抗拔力,占扩头段总抗拔力约70%。 相似文献