铁含量对滑石脱水动力学的影响及其地质意义

在常压下研究了2种不同铁含量滑石的原位X射线衍射高温脱水反应。选取粒径2~5μm的2种不同铁含量的滑石样品,在常压、空气氛围下进行了同步辐射原位X射线衍射脱水实验。实验结果表明,铁含量高的滑石脱水温度明显偏低,2个滑石样品在常压下发生明显脱水反应的温度相差达127℃以上。滑石在常压下的脱水动力机制为随机成核和生长机制,符合Avrami方程。将实验数据拟合Avrami方程得出:n=1.669。由实验结果可以推测,不同铁含量的滑石脱水深度可能有几十到上百千米的差别,研究铁含量与滑石脱水动力的相关性对于了解俯冲带浅-中源地震的成因机制具有重要意义。     

陕西泾阳南塬滑坡干湿黄土快速大剪切力学特性

借助于先进的多功能大型高速高压环剪试验机,针对陕西泾阳南塬滑坡中的饱和黄土、干燥黄土在快速大剪切位移条件下的力学响应特性进行了环剪试验研究。研究结果表明:1)在相同试验条件下,与干燥状态黄土相比,泾阳南塬黄土在饱和条件下抗剪强度指标降低。2)在连续快速剪切条件下,泾阳南塬滑坡饱和与干燥黄土均表现出应变软化特征,饱和黄土比干燥黄土的软化特征更加显著。3)在相同法向应力条件下,剪切速率对饱和和干燥黄土峰值强度均有显著影响,但两种状态下土体峰值强度随剪切速率变化特征不同。饱和黄土峰值强度随剪切速率的增大而增大,而干燥黄土峰值强度随剪切速率的增大而减小。4)在不同含水状态下,泾阳南塬滑坡黄土剪切力学特性变化规律具有不同的产生机理。其中,干燥黄土抗剪强度在连续剪切过程中主要受黏土颗粒间摩擦(阻)力、颗粒运移与定向排列以及剪切面形态的控制。与干燥黄土相比,饱和黄土峰值抗剪强度变化主要受土黏聚力的控制并受水的影响;土体内水的作用能够加剧其应变软化程度并可形成光滑平整的剪切面形态,进而对其峰后剪切应力变化产生影响。     

Lithofacies paleogeography mapping and reservoir prediction in tight sandstone strata: A case study from central Sichuan Basin,China

Sand-rich tight sandstone reservoirs are potential areas for oil and gas exploration. However, the high ratio of sandstone thickness to that of the strata in the formation poses many challenges and uncertainties to traditional lithofacies paleogeography mapping. Therefore, the prediction of reservoir sweet spots has remained problematic in the field of petroleum exploration. This study provides new insight into resolving this problem, based on the analyses of depositional characteristics of a typical modern sand-rich formation in a shallow braided river delta of the central Sichuan Basin, China. The varieties of sand-rich strata in the braided river delta environment include primary braided channels, secondary distributary channels and the distribution of sediments is controlled by the successive superposed strata deposited in paleogeomorphic valleys. The primary distributary channels have stronger hydrodynamic forces with higher proportions of coarse sand deposits than the secondary distributary channels. Therefore, lithofacies paleogeography mapping is controlled by the geomorphology, valley locations, and the migration of channels. We reconstructed the paleogeomorphology and valley systems that existed prior to the deposition of the Xujiahe Formation. Following this, rock-electro identification model for coarse skeletal sand bodies was constructed based on coring data. The results suggest that skeletal sand bodies in primary distributary channels occur mainly in the valleys and low-lying areas, whereas secondary distributary channels and fine deposits generally occur in the highland areas. The thickness distribution of skeletal sand bodies and lithofacies paleogeography map indicate a positive correlation in primary distributary channels and reservoir thickness. A significant correlation exists between different sedimentary facies and petrophysical properties. In addition, the degree of reservoir development in different sedimentary facies indicates that the mapping method reliably predicts the distribution of sweet spots. The application and understanding of the mapping method provide a reference for exploring tight sandstone reservoirs on a regional basis.     

Submersion simulation in a typical debris flow watershed of Jianzhuangchuan catchment,Loess Plateau

Debris flow is one of the most serious and frequent geological disasters that occur in the Loess Plateau. The outbreak of a debris flow is sudden, ferocious, swift, and destructive. The characteristics and mechanism of debris flow were explored in this study via survey, numerical simulation, and simulation analysis in a Loess Plateau area (Huangling County, Shaanxi Province, China). Numerical models and formulas corresponding to the occurrence and movement mechanism were established based on the HEC-RAS, HEC-GeoRAS, and SWAT results. The range of debris flow deposition was determined through capturing the debris flow free surface. A hydrological model and critical rainfall threshold were determined in order to provide technical support for debris flow forecasting in the Loess Plateau. The results suggest that 10-year floods do not submerge any portion of the basin. One village area was affected by the 100-year flood (total area of 0.648 km²) while four villages areas were submerged by the 1000-year flood (total area of 1.39 km²). The method presented here may provide a reliable scientific basis for mitigating loss due to debris flow hazards.     

地面激光扫描技术在建筑变形测量中的应用探讨

已有不少文献针对激光扫描在建筑变形测量中的应用进行了研究,但是国家和行业尚无三维激光扫描技术规程出台。本文通过应用调研、扫描仪的标称精度统计分析,以及具有针对性的试验,明确了激光扫描测量建筑变形的作业方法,确立了选用仪器精度、扫描测量的测回数、标靶入射角度等技术指标,为激光扫描技术在建筑变形测量中的工程应用提供了参考依据。     

中国天山积雪对气候变化响应的多通径分析

基于天山山区1961-2013年60个气象站点实测气温、降水、相对湿度、日照时数和积雪深度等气候资料,结合时间序列分析、空间分析以及通径分析等方法,全面精确地获取了天山山区气候变化特征以及气候变化对积雪的通径影响。结果表明：天山山区气候变化显著,主要表现为整体增暖、局部变湿与黯化;气候变暖导致天山山区固态降水（降雪）保证率明显降低,尤其是低海拔区域。各气象要素对积雪不仅存在直接的单因素影响而且各气象要素之间还存在间接的相互交叉、相互联结的多因素影响。单因素影响通径分别为气温、降水和日照时数对积雪深度的3条直接影响通径;多因素影响通径分别为气温、降水和日照时数通过相互之间的内在关系对积雪深度产生的6条间接影响通径。最终结果表明气温是积雪变化的主要影响因素,其影响效应远远大于降水和日照时数的影响。     

遥感聚合图像的快速拓扑矢量化方法

鉴于当前遥感图像矢量化效率普遍不高,提出了一种遥感聚合图像的快速拓扑矢量化方法。该方法对聚合图像中的聚合对象进行唯一性标号,并将这个标号作为属性赋予生成的矢量多边形,通过矢量多边形的标号间映射关系便可以快速建立复杂岛屿多边形的拓扑包含关系。试验表明,该方法能够精确地完成斑块对象边界追踪及复杂岛屿多边形处理,并显著提高矢量化的速度。     

Comparison of P‐wave attenuation models of wave‐induced flow

Wave‐induced oscillatory fluid flow in the vicinity of inclusions embedded in porous rocks is one of the main causes for P‐wave dispersion and attenuation at seismic frequencies. Hence, the P‐wave velocity depends on wave frequency, porosity, saturation, and other rock parameters. Several analytical models quantify this wave‐induced flow attenuation and result in characteristic velocity–saturation relations. Here, we compare some of these models by analyzing their low‐ and high‐frequency asymptotic behaviours and by applying them to measured velocity–saturation relations. Specifically, the Biot–Rayleigh model considering spherical inclusions embedded in an isotropic rock matrix is compared with White's and Johnson's models of patchy saturation. The modeling of laboratory data for tight sandstone and limestone indicates that, by selecting appropriate inclusion size, the Biot‐Rayleigh predictions are close to the measured values, particularly for intermediate and high water saturations.     

多测线变偏移距VSP地震各向异性反演

本文从一般弱各向异性介质参数反演中得到了使用两条相互正交的变偏VSP测线计算弱各向异性(WA)参数的反演公式. 如果仅仅使用qP波, 则可以确定9个独立的WA参数, 这9个WA参数可以完全地描述井中接收点在两个剖面内介质的各向异性性质. 通过对走时曲线进行最小二乘条件下的三次样条光滑, 可以获得慢度矢量的垂直分量和水平分量. 如果介质是横向非均匀介质, 则水平分量仅仅被用作反演时的约束条件. 为了获得偏振矢量, 本文引入质心计算方法, 该方法计算简单、 稳定, 而且不存在解的奇异问题. 在寻找与一般各向异性介质最接近的高对称性正交各向异性介质和TTI各向异性介质时, 使用qP波各向异性坐标变换方法和最小二乘求解方法, 得到了与一般各向异性介质最接近的正交各向异性和TTI各向异性参数及其对称轴方向参数的计算公式. 使用这些方法, 对瓜哇海地区布设的两条相互正交的变偏VSP测线数据进行各向异性反演, 获得了井中10个接收点处介质的WA参数. 数值计算和实际资料反演表明, 本文所使用的反演方法能够准确地得到VSP井中接收点处介质的WA参数, 这是地震勘探中研究地壳介质各向异性性质最直接和最可靠的方法.      

身体、身体观以及人文地理学对身体的研究

1970年代以来,伴随着消费主义和女权运动,身体研究在人文社会学科中兴起,一个被布莱恩·特纳（Bryan Turner）称之为“身体社会崛起”的时代来临了。身体研究成为西方人文与社会科学研究的“新大陆”,众多哲学家、社会理论学家纷纷投身于身体研究,重新解读了身体在认识世界和知识生产中的重要性。身体转向作为文化转向的一部分,同样受到了人文地理学家的关注。许多批判地理学家,如女性主义、马克思主义、反种族主义、后殖民主义、酷儿地理学家认为,身体研究是改善社会、文化、经济关系的可能途径。在“身体转向”的影响下,身体研究逐渐渗入到情感地理学、旅游地理学、乡村地理学等众多研究领域。与此同时,人文地理学家从人文社会科学中引入多种理论,如表演理论、精神分析法、非表征理论等对身体研究进行了探讨和阐释。基于这样的背景,梳理了西方人文地理学中有关身体研究的文献,归纳了人文地理学中身体研究的主要议题和理论,以及由此而展开的一系列具体的研究成果,此工作具有切实的学术意义并对后续相关研究的展开具有指导意义。