偏压隧道偏压应力比特征分析     

于清杨  刘伟  佴磊  代树林 《吉林大学学报(地球科学版)》2018,48(6):1797-1803

偏压隧道是公路和铁路建设中经常遇到的隧道类型,由于其受力的不对称性及设计、施工的特殊性,一直是隧道施工研究的热点。以往针对偏压隧道的研究主要集中在偏压隧道的成因、围岩稳定性、应力应变分布规律及施工影响等方面,但缺少对偏压隧道偏压应力比以及公路、铁路设计规范给出条件的偏压应力比的研究,而且公路和铁路设计规范中给出的偏压隧道对应的坡面倾角和隧道埋置深度缺少相关理论来支撑。本文针对铁路双线隧道设计规范给出的临界坡度和覆盖层厚度条件,采用数值模拟的方法,求出地形偏压隧道对称位置的应力比值,定量分析了规范给定条件下偏压应力比的特征值。结果表明：在保证安全的前提下,当Ⅲ级围岩拱肩应力比大于7.45、Ⅳ（土）级围岩拱肩应力比大于2.23、Ⅳ（石）级围岩拱肩应力比大于3.34、Ⅴ级围岩拱肩处应力比大于1.06时,可将隧道考虑成偏压隧道,从而为定量判别偏压隧道提供理论依据。  相似文献   

中国几个盆地原油轻烃单体和正构烷烃系列分子碳同位素研究   总被引：11，自引：0，他引：11  

张文正  裴戈  关德师  程坤芳 《地质论评》1993,39(1)

本文采用最新的GC/C/MS在线碳同位素分析技术,分析研究了鄂尔多斯、四川、塔里木等盆地原油及凝析油轻烃单体和正构烷烃系列分子碳同位素特征及分布模式。探讨了不同结构烃分子及同结构不同碳数烃分子之间碳同位素分配的某些规律。研究了一些典型成因原油轻烃单体和正构烷烃系列分子碳同位素特征及分布模式,为该项新技术在油气研究与勘探中的应用奠定了基础。同时在一些原油的成因上取得了新认识。  相似文献   

应用列联表方法研究化石群落关联性     

Lin Heping  Yuan Qingyang 《吉林大学学报(地球科学版)》1994,(1)

应用列联表方法研究化石群落间的关联性问题。列联表方法是从变量的独立性出发研究两两变量间的关系。该方法的优，或是不但能用数字表示两变量间的关联程度，而且还对其关联性作显著性检验，使所得结果更为精确。本文介绍的数学原理和计算方法，力求简明易懂。最后选择了实际例子借以说明列联表方法在研究此问题上的良好效果。  相似文献   

小兴安岭孙吴地区下白垩统美丰组火山岩年代学和岩石地球化学研究     

岳洪举  陆胜  于庆洋  翟艳超  张庆 《地质论评》2022,68(6):2138-2146

小兴安岭美丰组火山岩广泛出露,对于研究美丰组火山岩岩石地球化学特征具有重要意义。笔者等通过对小兴安岭孙吴地区美丰组火山岩进行岩相学、锆石U- Pb年代学、全岩主—微量元素地球化学研究,探讨了其形成时代、岩石成因及其构造环境。锆石U- Pb结果表明,美丰组形成于早白垩世（105. 2 ±0. 5 Ma）。美丰组以基性火山岩为主,属高钾钙碱性系列;富集Rb、Ba、Th、U、La、Ce,相对亏损Nb、Ti等元素;δEu=0. 71～0. 94,轻稀土略富集。轻、重稀土分馏不明显。岩石地球化学特征表明,美丰组火山岩的原始岩浆起源于地幔,受地壳物质的混染改造。研究区美丰组火山岩形成于伸展环境,是古太平洋板块向亚洲大陆板块俯冲背景下的产物。  相似文献   

全球气候变化问题的对策之我见     

张庆阳 《气候与环境研究》1998,3(3):275-281

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明确目标 强化措施 推进地震安全农居工程建设     

马志峰  孟晓花  张庆洋 《国际地震动态》2008,(9)

我国是一个农业大国,又是一个多地震国家.近年来随着经济社会的快速发展,农村面貌也发生了根本变化,但是农村民居的抗震设防工作仍十分薄弱.为了贯彻全国农村民居防震保安工作会议精神,枣庄市研究制定了推进农居地震安全工程的意见.本文简述了枣庄市政府推进农居安全工程工作的目标、任务、 实施步骤和措施.  相似文献   

Changes of visceral properties and digestive enzymes in the herbivorous marine teleost Siganus canaliculatus fed on different diets     

XIE Dizhi  XU Shude  WU Qingyang  CHEN Fang  WANG Shuqi  YOU Cuihong  LI Yuanyou 《海洋学报(英文版)》2018,(2)

The rabbitfish Siganus canaliculatus is one of the few cultured herbivorous marine teleosts. To better understand the digestive physiology of this fish and provide data for designing formulated feed using macroalgae as an ingredient, the changes of visceral properties and digestive enzyme activities were investigated after the juveniles were fed on different types of food including raw fish(RF), formulated diet(FD) or macroalgae Enteromorpha prolifra(EP) and Gracilaria lemaneiformis(GL) for eight weeks. The results showed that the hepatosomatic and viscerosomatic indices in the RF and FD groups, as well as the relative intestine length(RIL) in the EP and GL groups, were significantly higher than those in other groups. Additionally, differences in the histological structure of the liver and anterior intestine were also observed among different dietary groups. The hepatic nuclei were displaced to the periphery by lipid inclusions in fish fed RF. The highest levels of mucosal folds were found in the anterior intestines of fish fed macroalgae. Digestive enzyme activity profiles showed obvious fluctuations in the first three weeks, and then leveled off in the following weeks. The levels of protease, lipase and α-amylase in the alimentary tract showed changes related to the levels of dietary protein, lipid and carbohydrate, respectively.Although macroalgae significantly inhibited the activity of protease in the stomach, it increased RIL and the number of mucosal folds in the anterior intestine so as to compensate for the influences on protease activities in the stomach. This study suggests that the digestive tract of rabbitfish can well adapt to different diets, and needs about three weeks to physiologically acclimatize to the nutritional status, thus implying that rabbitfish are somewhat omnivorous.  相似文献   

Alteration and Reformation of Hydrocarbon Reservoirs and Prediction of Remaining Potential Resources in Superimposed Basins   总被引：1，自引：0，他引：1  

PANG Hong  PANG Xiongqi  YANG Haijun  LIN Changsong  MENG Qingyang  WANG Huaijie 《《地质学报》英文版》2010,84(5):1078-1096

<正>Complex hydrocarbon reservoirs developed widely in the superimposed basins of China formed from multiple structural alterations,reformation and destruction of hydrocarbon reservoirs formed at early stages.They are characterized currently by trap adjustment,component variation, phase conversion,and scale reformation.This is significant for guiding current hydrocarbon exploration by revealing evolution mechanisms after hydrocarbon reservoir formation and for predicting remaining potential resources.Based on the analysis of a number of complex hydrocarbon reservoirs,there are four geologic features controlling the degree of destruction of hydrocarbon reservoirs formed at early stages:tectonic event intensity,frequency,time and caprock sealing for oil and gas during tectonic evolution.Research shows that the larger the tectonic event intensity,the more frequent the tectonic event,the later the last tectonic event,the weaker the caprock sealing for oil and gas,and the greater the volume of destroyed hydrocarbons in the early stages.Based on research on the main controlling factors of hydrocarbon reservoir destruction mechanisms,a geological model of tectonic superimposition and a mathematical model evaluating potential remaining complex hydrocarbon reservoirs have been established.The predication method and technical procedures were applied in the Tazhong area of Tarim Basin,where four stages of hydrocarbon accumulation and three stages of hydrocarbon alteration occurred.Geohistorical hydrocarbon accumulation reached 3.184 billion tons,of which 1.271 billion tons were destroyed.The total volume of remaining resources available for exploration is～1.9 billion tons.  相似文献   

柴达木盆地西部狮子沟—英东构造带构造演化及控藏特征   总被引：1，自引：0，他引：1       下载免费PDF全文

隋立伟  方世虎  孙永河  杨春燕  孟庆洋  桂丽黎  陈琰 《地学前缘》2014,21(1):261-270

柴达木盆地西部狮子沟—英东构造带近年来陆续获得重要油气发现,油气探明储量超亿吨,勘探潜力巨大,但复杂构造、沉积演化控制下的油气成藏与油气分布规律有待进一步研究。文中通过对构造带不同构造部位的沉降史模拟、地层缩短率计算及构造样式、构造变形特征的综合分析与对比,结合包裹体测温、埋藏史模拟及主成藏期确定,明确了新生代构造变形特征及其成藏过程与油气分布的控制作用。研究表明:(1)构造带的演化可分为4个阶段。路乐河组(E1+2)—下干柴沟组下段(E13),初始弱断陷期;下干柴沟组上段(E23),快速沉降期;上干柴沟组(N1)—下油砂山组(N12),坳陷期;上油砂山组(N22)至今,构造抬升期。(2)构造带主要经历两次构造活动高峰,其中下干柴沟组(E23)时期构造活动控制了区内主力烃源岩演化。上油砂山组(N22)沉积末期构造变形控制了圈闭的形成及变形规律。(3)英东地区主要是两期成藏,分别发生于下油砂山组(N12)沉积末期和上油砂山组(N22)沉积末期;新生代构造演化及油气匹配关系控制了狮子沟—英东构造带的东、西成藏差异与油气分布。  相似文献   

小兴安岭孙吴地区下白垩统美丰组火山岩年代学和岩石地球化学研究     

岳洪举  陆胜  于庆洋  翟艳超  张庆 《地质论评》2022,68(4):2022072009-2022072009

小兴安岭美丰组火山岩广泛出露,对于研究美丰组火山岩岩石地球化学特征具有重要意义。本文通过对小兴安岭孙吴地区美丰组火山岩进行岩相学、锆石U- Pb年代学、全岩主—微量元素地球化学研究,探讨了其的形成时代、岩石成因及其构造环境。锆石U- Pb结果表明,美丰组形成于早白垩世（105.2 ±0.5Ma）。美丰组以基性火山岩为主,属高钾钙碱性系列;富集Rb、Ba、Th、U、La、Ce,相对亏损Nb、Ti等元素;δEu=0.71～0.94,轻稀土略富集。轻、重稀土分馏不明显。岩石地球化学特征表明,美丰组火山岩的原始岩浆起源于地幔,受地壳物质的混染改造。研究区美丰组火山岩形成于伸展环境,是古太平洋板块向亚洲大陆板块俯冲背景下的产物。  相似文献