脆弱性的概念及其评价方法

脆弱性研究是全球变化及可持续性科学领域关注的热点问题和重要的分析工具, 随着脆弱性研究受到越 来越多的关注, 对脆弱性的概念和评价方法的研究日益深入。对国内外相关研究中出现的脆弱性概念进行了归纳 总结, 并深入讨论了不同学者就脆弱性概念初步达成的共识及存在的分歧, 在此基础上明确了脆弱性概念的内涵。 依据脆弱性评价的思路, 将国内外脆弱性研究中出现脆弱性评价方法分为五大类, 分析了各种评价方法的优缺点, 指出了脆弱性评价中应遵循的基本原则。最后, 结合脆弱性研究的发展趋势, 指出面向多重扰动的脆弱性评价、耦 合系统的脆弱性评价、复杂系统的不确定问题、脆弱性评价的尺度问题等是目前脆弱性评价研究中亟待开展的研 究内容。     

综合地球物理方法对黄海地区前新生代残留盆地分布的研究

残留盆地由于埋深大、构造复杂等特点,单一的地球物理方法对残留盆地的勘探与解释存在很大的局限性,因此运用综合地质地球物理方法对前新生代残留盆地进行研究,可以充分发挥各种方法的优势,有效地解决油气勘探中的有关问题.本文以黄海地区前新生代残留盆地为研究对象,以"区域控制局部,深层约束浅层"为指导思想,在前人研究的基础上,运用重、磁、地震、钻井和区域地质等资料进行了综合研究,根据研究与计算结果勾绘了黄海地区前新生代残留盆地的宏观构造格架,并分析了残留盆地分布特征.     

与斑岩型铜矿有关的角砾岩(筒)

斑岩型铜矿床是重要的铜矿类型,在已探明的铜储量中斑岩型铜矿居首位.研究认为,在板块构造的敛合带上,斑岩铜矿发育地区,常见有角砾状地质体和角砾岩筒.这些角砾状地质体和角砾岩筒对矿化与富集起着重要作用,是斑岩铜矿的重要找矿标志,有时其本身就是铜矿体.本文中从理论与野外工作相结合的角度,总结了与斑岩型铜矿床有关的角砾状地质体和角砾岩筒的类型及地质特征,通过具体实例介绍了与斑岩铜矿有关的角砾岩筒的找矿思路与方法,适宜野外工作的实际应用.     

综合物探方法在太原市蒙山采空区探测中的应用

针对太原市蒙山煤矿采空区地形起伏较大、需弯线测量等因素制约的特殊场地条件,提出了阵列形式观测的高密度电阻率法和单点测量方式的瞬变电磁法相结合的综合物探方法.前者二维异常反演分辨率较高,可弥补瞬变电磁法浅部探测盲区,后者具有探测深度大的优势,采用一维异常反演方式可弥补高密度电阻率法受剖面折线展布和地形起伏影响的缺点.由此查明了该矿区采空区的位置及分布情况,后期钻探验证表明所采用的综合物探方法是行之有效的.该综合物探方法组合模式实现了两种物探方法的优势互补,可为同类场地条件下探测煤层采空区提供有意义的借鉴.     

利用爆破事件分析不同速度模型下常规定位方法定位结果

地震定位对速度模型的依赖性很强。四川地区地形复杂,常规工作中可选取多种速度模型进行定位。川西龙门山断裂带为东南部四川盆地和西北部青藏高原东部山区的明显分界线,近年在此断裂带上发生多次较大地震。对发生在该断裂带附近的6个爆破事件和15个天然地震重新定位,并对比结果。研究表明,相同台站包围情况下,川滇3D速度模型稳定性最好,但对浅表爆破不太准确。相比HypoSat(一维速度模型)组合,台站分布对Hypo2000(一维速度模型)和Hypo2000(赵珠速度模型)组合的定位结果影响较大。     

工程物探方法在上海城市建设与管理中的应用

工程物探是各学科和地球物理学的交叉学科,是目前应用地球物理领域中的一个重要的分支,它以地球物理学的理论、方法和技术来研究和勘查各种地球物理场的变化,提取人类活动(工程)对地质体原有状态的影响,探测地下目的体,评价工程质量,为工程的选址、建设、施工质量及安全性做出评价。上海城市建设工程物探的应用和相应的方法技术及工作程序,可供非物探专业的工程技术人员参考和借鉴。     

A multiphase approach for evaluating the horizontal and rocking impedances of pile group foundations

This paper advocates the use of a multiphase model, already developed for static or quasi‐static geotechnical engineering problems, for simulating the behaviour of piled raft foundations subject to horizontal as well as rocking dynamic solicitations. It is shown that such a model, implemented in a FEM code, yields appropriate predictions for the foundation impedance characteristics, provided that shear and bending effects in the piles are taken into account, thus corroborating the findings of the asymptotic homogenization theory. Besides, it is notably pointed out that such a multiphase‐based computational tool makes it possible to assess the dynamic behaviour of pile groups in a much quicker way than when using direct numerical simulations, which may face oversized problems when large pile groups are concerned. Copyright © 2016 John Wiley & Sons, Ltd.     

Why asymptotic limit of the acid dissolution capacity can lead to a sharp dissolution front in chemical dissolution of porous rocks?

The use of the asymptotic limit can greatly simplify the theoretical analysis of chemical dissolution front instabilities in fluid‐saturated rocks and therefore make it possible to obtain mathematical solutions, which often play a crucial role in understanding the propagation behavior of chemical dissolution fronts in chemical dissolution systems. However, there has been a debate in recent years that the asymptotic limit of the acid dissolution capacity (i.e., the acid dissolution capacity number approaching zero) alone cannot lead to a sharp dissolution front of the Stefan type in the acidization dissolution system, in which the dissolvable minerals of carbonate rocks are chemically dissolved by the injected acid flow. The acid dissolution capacity number is commonly defined as the ratio of the volume of the carbonate rock dissolved by an acid to that of the acid. In this paper, we use four different proof methods, including (i) direct use of the fundamental concepts; (ii) use of the mathematical governing equations of an acidization dissolution system; (iii) use of the different time scaling approach; and (iv) use of a moving coordinate system approach, to demonstrate that the asymptotic limit of the acid dissolution capacity can indeed lead to sharp dissolution fronts of the Stefan type in acidization dissolution systems on a much larger time scale (than the dissolution time scale). Our new finding is that on the reaction time scale, the condition of the conventional time derivative of porosity approaching zero alone can ensure that the acidization dissolution front has a sharp shape of the Stefan type. Copyright © 2017 John Wiley & Sons, Ltd.     

Bound and mobile soil water isotope ratios are affected by soil texture and mineralogy,whereas extraction method influences their measurement

Questions persist about interpreting isotope ratios of bound and mobile soil water pools, particularly relative to clay content and extraction conditions. Interactions between pools and resulting extracted water isotope composition are presumably related to soil texture, yet few studies have manipulated the bound pool to understand its influence on soil water processes. Using a series of drying and spiking experiments, we effectively labelled bound and mobile water pools in soils with varying clay content. Soils were first vacuum dried to remove residual water, which was then replaced with heavy isotope-enriched water prior to oven drying and spiking with heavy isotope-depleted water. Water was extracted via centrifugation or cryogenic vacuum distillation (at four temperatures) and analysed for oxygen and hydrogen isotope ratios via isotope ratio mass spectrometry. Water from centrifuged samples fell along a mixing line between the two added waters but was more enriched in heavy isotopes than the depleted label, demonstrating that despite oven drying, a residual pool remains and mixes with the mobile water. Soils with higher clay + silt content appeared to have a larger bound pool. Water from vacuum distillation samples have a significant temperature effect, with high temperature extractions yielding progressively more heavy isotope-enriched values, suggesting that Rayleigh fractionation occurred at low temperatures in the vacuum line. By distinctly labelling bound and mobile soil water pools, we detected interactions between the two that were dependent on soil texture. Although neither extraction method appeared to completely extract the combined bound and mobile (total water) pool, centrifugation and high temperature cryogenic vacuum distillations were comparable for both δ²H and δ¹⁸O of soil water isotope ratios.     

基于ArcMap的地图制作研究

随着计算机技术的飞速发展,计算机软件为地图设计和制作提供了更加便捷的操作模式,电子地图的出现摆脱了传统纸张对地图的限制,使其可以更好地为用户服务。ArcMap是一个统一的地理信息平台,在数据库制作、符号制作和地图装饰等方面具有独特的优势,适用范围广泛,在林业、牧业、电力等多行业具有非常好的数据展现效果,方便用户浏览、搜索和定位。本文从ArcMap制图流程入手,研究不同流程中制图方法。