周期荷载作用下盐岩声发射特征试验研究

通过改变恒幅荷载条件下的上限应力、下限应力以及加载速率等试验条件,基于声发射技术对盐岩疲劳损伤特征进行试验研究。试验发现,盐岩声发射信号出现在加载阶段和卸载初期,而砂岩声发射信号一般集中出现在上限应力处;盐岩疲劳寿命对下限的依赖程度大于砂岩;随着上限应力的增大,盐岩声发射振铃数增多。加载速率的提高会加速盐岩的疲劳破坏。通过对比声发射振铃数累计曲线和应变累计曲线,发现两者有很好的对应关系,说明二者在反映盐岩疲劳损伤时具有一致性。最后对盐岩进行3级变幅荷载试验,发现第3级声发射振铃数比相同上、下限应力的恒幅荷载条件下多,说明变幅荷载造成的盐岩损伤比恒幅荷载条件下严重。     

Seasonal timing of stratospheric final warming associated with the intensity of stratospheric sudden warming in preceding winter

The association of seasonal timing of stratospheric final warming events(SFWs) in spring and the occurrence of major and minor stratospheric sudden warming events(SSWs) in midwinter were investigated through statistical analysis, parallel comparison, and composite analysis, based on the NCEP-NCAR reanalysis dataset covering 1958–2012. It was found that the intensity and occurrence of winter SSW events can largely affect the timing of spring SFWs. Specifically, the SFW onset dates tend to be later(earlier) after the occurrence(absence) of winter major SSWs. However, the occurrence or absence of minor SSWs does not change the frequency of early and late SFWs. A parallel comparison of the temporal evolution of the anomalous circulation and planetary-waves between major SSW and minor SSW winters indicates that the stratospheric polar vortex(polar jet) will keep being anomalously stronger 30 days after major SSW onset. And the associated significant negative Eliassen-Palm(EP) flux anomalies can persist for as long as 45 days after major SSW events. In contrast, the circulation anomalies around the occurrence of minor SSW events can last only a few days. To further verify the possible influence of the occurrence of major SSWs on the seasonal timing of SFWs, composite analysis was performed respectively for the 21 major-SSW years, 15 minor-SSW years, and the 15 non-SSW years. Generally, planetary-wave activity in the extratropical stratosphere tends to be stronger(weaker) and the westerly polar jet is anomalously weaker(stronger) in major-SSW(non-SSW) winters. But in the following spring, the planetary-wave activity is weaker(stronger) accompanied with an anomalously stronger(weaker) stratospheric polar vortex. In spring after minor-SSW years, however, the stratospheric polar vortex and the westerly polar jet exhibit a state close to climatology with relatively gentle variations.     

Ore-forming fluid characteristics and genesis of vein-type lead-zinc mineralization of Xiaohongshilazi deposit,Jilin Province,China

The Xiaohongshilazi mineral deposit in Jilin Province,China,is located in the accretion zone in the northern margin of the North China Block. The deposit contains two types of ore bodies: layered Pb-Zn ore bodies in volcanic rock and vein-hosted Pb-Zn ore bodies controlled by fractures. The vein Pb-Zn ore bodies are strictly controlled by tectonic fracture zones trending in S-N direction,which comprise sulfide veins or sulfidebearing quartz veins distributed along faults or structural fissures. The ores mainly appear mesh-vein and vein structures,and also show solid-solution separation and metasomatic textures. The metal minerals are mainly sphalerite,galena,and pyrite,etc. Wall-rock alteration includes mainly sericitization,chloritization,silicification and carbonatization,etc. Microscope observations and Raman spectroscopy analyses indicate that the oreforming fluid of the vein Pb-Zn ore bodies was mainly magmatic water with low temperature,low salinity,and a shallow depth of metallogenesis( ~ 1.5 km). Sulfur and lead isotope analyses indicate that the sulfide source is mainly formation sulfur or biogenic sulfur,which is similar to the sulfur source of hydrothermal deposit( negative( δ~(34) S values),while the main Pb source was the upper crust with some mantle input. This article argues that the vein Pb-Zn ore body of the Xiaohongshilazi deposit is a low-to medium-temperature hydrothermal vein type related to the formation of a shallow magma chamber.     

渭河断裂窖店浅层地震与钻孔联合剖面研究

为确定渭河断裂中部隐伏段的位置,在咸阳窑店布设了浅层地震勘探测线,在浅层地震勘探资料对断层解译的基础上,进一步开展了窑店和陈家沟钻孔联合剖面勘探工作,详细查明了渭河断裂的精确位置和组合特征,结合钻孔土样光释光(OSL)年龄测试和区域地层资料,深入研究了渭河断裂带最新活动年代和滑动速率等特征。     

青藏高原可可西里卓乃湖溃堤成因及其影响分析

受青藏高原暖湿化趋势的影响,近年来高原湖泊水位普遍上涨,湖泊溃堤时有发生.利用青藏高原可可西里卓乃湖、库赛湖、海丁诺尔湖和盐湖所在区域的TM（ETM+）等历史文献数据和环境减灾卫星（HJ1A/B） CCD数据,结合五道梁气象站气温、降水资料,分析了卓乃湖周边湖泊面积变化情况.结果表明：1961-2014年近54 a来,可可西里地区持续增加的降水是卓乃湖溃堤的基础,2011年8月22日之前的两次强降水过程和之后的持续降水是导致卓乃湖湖水大量外泄,并最终溃堤的主要原因;溃堤前的两次地震可能对卓乃湖的湖盆结构产生了一定的影响,从而加速了溃堤过程.溃堤导致湖岸线退缩,并产生大片的沙化土地,恶化了藏羚羊的产仔环境,对周边草地生态环境和重大工程设施产生了不利影响.     

基于耦合欧拉-拉格朗日法充灌袋挤淤过程的有限元研究

在含水率大、承载能力低的软土地基上,利用充灌砂袋进行挤淤置换的方法工艺简单、施工方便、处理效果明显,已经广泛地应用在建造围埝和修筑道路中。充灌袋下沉到一定深度后,其重量与地基承载力相等,从而达到极限平衡状态。充灌袋挤淤所达到的深度与其高度存在一定的对应关系,在工程中确定此关系十分重要。通过3组不同宽度的挤淤模型试验,得到充灌袋下沉量与充灌袋高度的曲线关系、淤泥的位移特性及隆起量。利用ABAQUS中耦合欧拉-拉格朗日法（CEL法）,将充灌袋和淤泥分别用拉格朗日体和欧拉体描述,模拟充灌袋挤淤下沉的过程,将模拟得到的充灌袋下沉深度和高度的关系、淤泥的位移特点与试验结果以及理论公式进行对比。结果表明,CEL法模拟得到的结果与试验结果、理论解具有很好的吻合性,说明利用CEL法可以较好地模拟充灌袋的挤淤问题。     

基于“尺度”的区域环境管理的几点思考——以中观尺度区域(省域)环境管理为例

当代人类解决环境问题的途径和手段已从环境治理、环境管理到区域环境管理。基于尺度的区域环境管理是区域管理的重要组成部分,尺度是确定时空范围层次归属的综合概念,区域环境管理的尺度有宏观、中观和微观之分,其中中观尺度镶嵌在宏观和微观尺度之间,具有承上启下的作用。中观尺度区域环境管理包括区际、区内和次区域环境管理3个层次。基于上述认识,分析了尺度在区域环境管理中的重要作用,探讨了区域环境管理的"尺度"范围确认依据,重点论述了中观尺度区域环境管理的必要性、特点、层次镶嵌性及其管理模式的创新。     

基于房屋普查数据的房屋增长规律研究

以辽宁省县级以上城镇房屋普查数据、辽宁农村民居房屋普查数据、统计年鉴及抽样调查等房屋数据为基础,对房屋普查数据统计单元进行重新划分及统计计算,实现了房屋普查数据与应急基础数据库房屋数据单元的统一。通过对统计单元各种房屋结构增长率的计算,结合统计分析方法,给出了辽宁省1134个乡镇级统计单元的房屋增长率分类情况。     

测量学实践教学的改革与实践

测量学是一门技术性和实践性很强的专业基础课,实践教学是整个教学过程中的重要环节。近几年来,测绘工程系以土木工程等6个本科专业为试点,从更新实践教学内容和教学方法、加强实践教学基础条件建设、创新实践教学考核评价方法等方面进行了系统的研究和大胆的改革,建立与完善了一套完整的测量学实践教学体系,在培养学生的合作精神和动手能力方面收到了良好效果。     

分形技术在川西坳陷储层裂缝预测中的应用

川西坳陷是四川盆地油气勘探的重点,而须家河组二段又是该区域重要的储层。该储层具有非均质性强、致密化程度高的特点,裂缝发育情况对油气勘探具有决定性作用。通过对分形技术的原理、方法的介绍,并利用该方法对须二段储层的裂缝进行预测。结果表明,油气藏的存在与否与裂缝发育和盖层发育两个因素直接相关。研究区内须二段储层大部分属于裂缝发育区,对油气勘探很有利。