采空塌陷区地表建筑物变形特征分析及破坏机理研究

采空区建筑物的变形特性研究,一直是采空塌陷灾害的一个重要方向。本文以北京市房山区史家营乡大村涧村采空塌陷为背景,在充分分析采空区上方建筑物砖墙上裂缝形态及分布规律的基础上,从建筑物受力方面探讨了裂缝产生的原因,并采用数值模拟方法对采矿影响下建筑物的变形破坏机理进行浅析,研究结果不仅可为建筑物加固和维修提供依据,还可为采空塌陷区治理提供参考。     

陕西省明长城文物保护监测

结合地理国情普查试点工作的技术和方法,详细阐述了陕西省明长城文物保护监测生产过程中地理国情要素信息提取方法,获取明长城监测数据,对监测成果进行统计分析,总结明长城文物保护监测生产技术方法,并提出保护明长城的建议.     

地面固定式激光扫描点云中建筑物墙面信息的识别提取

地面固定式激光扫描系统能够获取大面积高分辨率的被测对象表面三维数据,本研究通过对固定式LiDAR激光数据做初分类,从地面点中粗提取具有少量噪声的建筑墙面数据,然后利用平面区域分割算法和立面约束条件提取建筑物墙面数据。在对两份固定式三维激光扫描点云的实验中,通过对不同分辨率的数据利用本文所提算法都取得了较好的墙面提取效果,实验证明了该方法的有效性。     

Displacement transfer from fault-bend to fault-propagation fold geometry: An example from the Himalayan thrust front

The leading edge of the ENE-trending Himalayan thrust front in Pakistan exhibits along-strike changes in deformational style, ranging from fault-bend to fault-propagation folds. Although the structural geometry is very gently deformed throughout the Salt Range, it becomes progressively more complex to the east as the leading edge of the emergent Salt Range Thrust becomes blind. Surface geology, seismic reflection, petroleum well, and chronostratigraphic data are synthesized to produce a 3-D kinematic model that reconciles the contrasting structural geometries along this part of the Himalayan thrust front. We propose a model whereby displacement was transferred, across a newly-identified lateral ramp, from a fault-bend fold in the west to fault-propagation folds in the east and comparable shortening was synchronously accommodated by two fundamentally different mechanisms: translation vs. telescoping. However, substantially different shortening distribution patterns within these structurally contrasting segments require a tear fault, which later is reactivated as a thrust fault. The present geometry of this S-shaped displacement transfer zone is a combined result of the NW–SE compression of the lateral culmination wall and associated tear fault, and their subsequent modification due to mobilization of underlying ductile salt.     

Stained Glass and Climate Change: How are they Connected?

As expressions of regional architecture, sacred (Christian) Gothic structures often possess several adaptations to their prevailing climate regime. The late medieval (Gothic) period in northern Europe is also, according to the evidence presented here, marked by a transition from warm and sunny to cooler and cloudier conditions. It is within the context of this climate change that we consider one of the most important features in Gothic churches—interior daylighting—during the transitional period (the thirteenth to the end of the fifteenth centuries) between the Medieval Warm Period (MWP) and the Little Ice Age (LIA). This paper seeks to determine whether increasingly cloudy conditions over northern continental Europe, in part due to a shift in North Atlantic Oscillation (NAO) phase, may have influenced the use of more white glass in the fourteenth century. To the best of our knowledge, this is the first time an extensive daylighting dataset has been collected in medieval sacred interiors. From an analysis of these illuminance and luminance data collected in European churches and cathedrals, we find that high-translucency glazing is associated with limited lighting gains compared to full-colour programs under sunny conditions but substantial lighting improvements (up to an order of magnitude) for cloudy conditions. Additionally, we find that backlighting from direct sunlight produces significant obscuration of some of the iconographical glass when interiors are dominated by high-translucency glazing, further suggesting that these interiors are not ideal for sunny conditions.

[Traduit par la rédaction] Étant donné que les cathédrales gothiques (chrétiennes) sont des expressions de l'architecture régionale, plusieurs adaptations au climat de l’époque y ont souvent été apportées. À la fin du Moyen Âge (période du gothique), le climat chaud et ensoleillé en Europe du nord continentale a fait place à un climat plus froid et plus nuageux, d'après les preuves que nous présentons ici. C'est donc dans la perspective de ce changement climatique que nous nous penchons sur l'un des éléments les plus importants de l'architecture des églises gothique, l’éclairage naturel intérieur, durant la transition (du XIII^e siècle à la fin du XV^e siècle) entre la période chaude médiévale (MWP) et le petit âge glaciaire (LIA). Dans le présent article, nous voulons notamment évaluer si l'utilisation de plus en plus fréquente du vitrail blanc au XIV^e siècle s'expliquerait par les conditions plus nuageuses en Europe du nord continentale, attribuables en partie à un changement dans l'indice d‘oscillation nord-atlantique (NAO). À notre connaissance, c'est la première fois qu'une série élaborée de données a été recueillie sur l’éclairage à l'intérieur des cathédrales gothiques. L'analyse des données sur l’éclairement lumineux et la luminance lumineuse dans les églises et les cathédrales d'Europe nous permet de constater que le verre très translucide présente peu d'avantages comparativement au verre plein coloré dans des conditions ensoleillées, mais qu'il améliore considérablement l’éclairage dans des conditions nuageuses (jusqu’à 10 fois). De plus, nous constatons que l’éclairage en contre-jour produit par l'ensoleillement direct obscurcit une partie des pièces de verre ornées d'icônes lorsque le verre très translucide domine à l'intérieur, ce qui confirme une fois de plus qu'il ne s'agit pas d'un aménagement idéal pour les conditions ensoleillées.     

基于层次分析法与频率比模型的采空塌陷危险性评价

采空塌陷危险性评价是编制地质灾害防治规划、开展地质灾害防治与监测预警工作的重要依据。本文采用层次分析法与频率比模型相结合构建了采空塌陷危险性评价模型（AHP-PF组合模型）。以沈阳市蒲河-清水矿区为例,考虑了地质条件、地表特征、开采条件等3方面影响因素,选取了第四纪覆盖类型、第四纪松散层厚度、地质构造复杂程度、可采煤层顶板强度指标、煤层倾角、地表沉陷速率、采深采厚比、采空区叠置层数等8个评价指标,利用AHP-PF组合模型计算各指标权重及频率比,最后进行采空塌陷危险性分区。评价结果表明,采空塌陷危险性高区主要集中在采深采厚比小、沉陷速率大及目前仍在开采的区域,该区域是地质灾害防治、搬迁避让的重点区域。     

Modelling mechanical behaviour of limestone under reservoir conditions

High porosity and low permeability limestone has presented pore collapse. As fluid is withdrawn from these reservoirs, the effective stresses acting on the rock increase. If the strength of the rock is overcome, pore collapse may occur, leading to irreversible compaction of porous media with permeability and porosity reduction. It impacts on fluid withdrawal. Most of reservoirs have been discovered in weak formations, which are susceptible to this phenomenon. This work presents a study on the mechanical behaviour of a porous limestone from a reservoir located in Campos Basin, offshore Brazil. An experimental program was undergone in order to define its elastic plastic behaviour. The tests reproduced the loading path conditions expected in a reservoir under production. Parameters of the cap model were fitted to these tests and numerical simulations were run. The numerical simulations presented a good agreement with the experimental tests. Copyright © 2006 John Wiley & Sons, Ltd.     

榆林地区黄土窑洞崩塌灾害的多发性原因及其防治对策研究

本文通过对榆林地区米脂、绥德、子洲、清涧、吴堡和榆林市黄土窑洞建窑环境进行考察,总结分析了在黄土介质中修建的土窑洞崩塌灾害多发性原因,并提出了可操作性的防治对策。该对策可广泛适用于我国黄土窑洞分布区。