基于CASIO fx-5800计算器编制计算曲线桥墩坐标

根据单线铁路曲线桥墩与路线中线之间的设计关系,以及桥梁工作线、桥墩横向偏心、纵向偏心。基于CASIO fx-5800计算器编制计算曲线桥墩坐标,将结合工程实例讨论曲线桥墩上任意点坐标计算,施工中常用方法。     

Prediction of Shale Gas Pressure based on Multi-channel Seismic Inversion in Fuling

The accurate prediction of formation pressure is important in oil/gas exploration and development. However, the achievement of this goal remains challenging, due to insufficient logging data and the low predictive data accuracy from seismic data. In this work, a case study was carried out in the Baima area of Wulong, in order to develop a workflow for accurately predicting shale gas formation pressure. The multi-channel stack method was first used, as well as the inversion of single-channel seismic data, to construct velocity and density models of the formation. Combined with the existing well-logging data, the velocity and density models of the whole well section were established. The shale gas formation pressure was then estimated using the Eaton method. The results show that the multi-channel seismic stacking method has a higher accuracy than the inversion of the formation velocity obtained by the single-channel seismic method. The discrepancies between our predicted formation pressure and the actual formation pressure measurement are within an acceptable range, indicating that our workflow is effective.     

冀中坳陷下第三系构造背斜成因分类

冀中坳陷的下第三系构造背斜主要形成于伸展断陷背景下 ,与正断层系统联系紧密。根据背斜与断层关系 ,基本类型可分为 3种 ,即纵向、横向和复合背斜 ;根据具体构造力学背景 ,这 3种背斜可进一步分为 8类 ,即 :重力滑动型、张扭型、拆离拱张型、逆牵引型、断层线偏转型、侧接型、复杂变换型、复合型。这些背斜是构造演化的产物 ,在一定程度上指示了坳陷内的构造演化规律 ,同时又是形成油气藏的有利圈闭 ,目前已取得显著勘探成效     

基于地震波速度预测岩体物性参数模型与应用

以地震属性和钻孔测井参数为基础,依据试验数据构建数学模型,实现对煤层顶底板岩石物性参数的定量预测。通过试验拟合出纵横波波速之间关系、波速与密度的关系、动静杨氏模量、动静泊松比之间的关系,且相关程度较高。依据试验模拟结果对淮南刘庄区煤层顶底板岩石物性参数及孔隙度进行了预测。结果表明该地区的物性参数分布规律明显,且与实测结果吻合较好。模型计算与实例应用证实地震信息用于预测岩石力学参数具有可行性。     

A method for evaluating the longitudinal functional connectivity of a river–lake–marsh system and its application in China

The longitudinal functional connectivity of a river–lake–marsh system (RLMS) refers to the actual water-mediated transport of material from upstream to downstream areas along a spatial gradient and is fundamental to understand hydrological and biogeochemical cycles. However, due to a lack of consensus on appropriate data and methods, the quantification of connectivity is still a challenge, especially at the catchment scale. We developed a new method to evaluate longitudinal functional connectivity based on fluxes of materials (water, sediment, and chemicals) along a RLMS. The calculation of fluxes is based on the longitudinal pattern of terrain gradient, which influences transport efficiency, and on contributions from hillslopes, which set the initial spatial template of material loading to the RLMS. We evaluate the contributions from hillslopes to RLMS based on a new modified version of the index of sediment connectivity (IC) proposed by Borselli et al. (2008) and revised by Chartin et al. (2017).We applied this method to the Baiyangdian Basin covering an area of 3.4 × 10⁴ km² in China and quantified longitudinal functional connectivity during normal, wet, and dry periods(April, July and December) in year 2016. We found that areas with good structural connectivity exhibited poor functional connectivity during the normal and dry periods. Modelling testing with discharge data from hydrological stations and measured chemicals from Baiyangdian Lake was satisfactory in test periods. We conclude that public data and Digital Elevation Model-derived information can be used to reliably map the longitudinal functional connectivity of RLMSs. The proposed method provides a useful tool for monitoring and restoring the longitudinal functional connectivity of RLMSs and our results indicate that efforts aimed at restoring functional connectivity in RLMSs should take into account landscape patterns that can greatly influence fluxes in the watershed.     

Mapping changes of residence with passive mobile positioning data: the case of Estonia

Similar to every process involving quantitative research, the study of migration heavily depends on the data available for analysis. The available movement data limit the type of questions that can be asked, and as a result, certain aspects of human spatial mobility have yet to be examined. The development of information and communication technologies and their widespread adoption offers new datasets, methods and interpretations that make it possible to study social processes at a new level. For example, mobile positioning data can aid in overcoming certain constraints embedded in traditional data sources (such as censuses or questionnaires) for study of the connections between daily mobility and change of residence. This study presents a framework for mapping changes of residence using data from passive mobile positioning and an anchor point model to better understand the limits of these methods and their contribution to understanding long-term mobility. The study concludes that the most important considerations in monitoring change of residence using passive mobile position data include the continuity of the time-series data, the varying structure of the mobile tower network and the diversified nature of human mobility. The fine spatial and temporal granularities of passive mobile positioning data allow us to study human movement at a detailed scale.     

走廊南山河流纵剖面高海拔裂点的成因

河流水力侵蚀物理模型表明基岩河道纵剖面在均衡状态时表现为平滑上凹的形态,其特征反映了构造、基岩抗侵蚀能力和气候的作用;然而自然界河道纵剖面多呈现以裂点为特征的不均衡形态,不均衡的剖面形态以及裂点的研究同样可以对外力作用的变化起到很好的指示作用。位于北祁连的走廊南山高海拔河道纵剖面普遍呈现不均衡形式且发育海拔较高的裂点。通过对裂点成因分析发现,这些裂点并不主要受控于岩性、气候、构造等因素,而反映了冰川作用遗留地形与河流地形的分界。这一结果说明在对河道纵剖面高海拔裂点进行分析时要考虑到古冰川遗留地形也会对现代河道纵剖面产生重要影响,为进一步认识和理解造山带地貌演化以及控制因素提供了思路。     

重磁等值线与经纬网的分离及其矢量化

本文利用经纬网在局部范围的直线性直线的平均ｆｒｅｅｍａｎ链码等于其上任意一点的链码的这一特性,达到自动分离经纬网与等值线的目的,为实现等值线图的自动矢量化打下了基础。     

无人机航摄相片倾角对立体高程扭曲的影响分析

通过对相片倾角对航测高程误差影响的理论分析,结合无人机低空摄影实际生产出现的问题,提出无人机低空摄影飞行姿态控制的指导性建议。     

Decadal link between longitudinal morphological changes in branching channels of Yangtze estuary and movement of the offshore depo-center

In estuaries, the morphology of inland and offshore areas usually evolves synergistically. This study examines the decadal link between longitudinal changes in morphology of branching channels and movement of the offshore depo-center (where sediment deposition rate is maximum) of the Yangtze River estuary, under intense human interference. Integrated data analysis is provided on morphology, runoff discharge, and ebb partition ratio from 1950 to 2017. Channel-volume reductions and change rates between isobaths in branching channels reflect the impact of estuarine engineering projects. Ebb partition ratio and duration of discharge ≥ 60 000 m³ s^-1 act as proxies for the water excavating force in branching channels and runoff intensity. It is found that deposition occurs in the lower/upper sub-reaches (or further downstream/upstream channels) of the inland north/south branching channels, and the offshore depo-center moves southward or southeastward, as runoff intensity grows; the reverse occurs as runoff intensity declines. This is because the horizontal circumfluence in the Yangtze estuary rotates clockwise as ebb partition ratios of the north/south branching channels increase/decrease for increasing runoff, and conversely rotates anticlockwise for decreasing runoff. Land reclamation activities, the Deepwater Channel Project, and the Qingcaosha Reservoir have impacted greatly on longitudinal changes of morphology in the North Branch and the South Passage and on ebb partition ratio variations in the North/South Channel and the North/South Passage. Dam-induced runoff flattening has enhanced deposition in the upper/lower sub-reaches of the north/south branching channels and caused northward movement of the offshore depo-center, except in areas affected by estuarine engineering projects. Dam-induced longitudinal evolution of branching channel morphology and offshore depo-center movement will likely persist in the future, given the ongoing construction of large cascade dams in the upper Yangtze and the completion of major projects in the Yangtze estuary. © 2020 John Wiley & Sons, Ltd.