重庆秀山县岩溶地区公路边坡溶洞治理方案

岩溶地区公路边坡具有地面坡度陡峭,基岩破碎程度高,坡积及残坡积层分布复杂,地下水活跃以及边坡治理施工条件困难等特点。其加固处理不但要考虑溶洞本身的受力情况,更需要考虑边坡的整体稳定性。通过对重庆秀山县岩溶地区边坡中出现的垂直于滑坡面的溶洞受力分析,从边坡的整体稳定性出发,研究岩溶地区公路边坡坍塌的应急加固治理方案。     

Stable isotope study of precipitation and cave drip water in Florida (USA): implications for speleothem-based paleoclimate studies†

Stable isotopes of hydrogen and oxygen were used to examine how the isotopic signal of meteoric water is modified as it travels through soil and epikarst into two caves in Florida. Surface and cave water samples were collected every week from February 2006 until March 2007. The isotopic composition of precipitation at the investigated sites is highly variable and shows little seasonal control. The δ¹⁸O vs. δ²H plot shows a mixing line having a slope of 5.63, suggesting evaporation effects dominate the isotopic composition of most rainfall events of less than 8 cm/day, as indicated by their low d-excess values. The δ¹⁸O values of the drip water show little variability (<0.6‰), which is loosely tied to local variations in the seasonal amount of precipitation. This is only seen during wintertime at the Florida Caverns site.

The lag time of over two months and the lack of any relationship between rainfall amount and the increase in drip rate indicate a dominance of matrix flow relative to fracture/conduit flow at each site. The long residence time of the vadose seepage waters allows for an effective isotopic homogenisation of individual and seasonal rainfall events. We find no correlation between rainfall and drip water δ¹⁸O at any site. The isotopic composition of drip water in both caves consistently tends to resemble the amount-weighted monthly mean rainfall input. This implies that the δ¹⁸O of speleothems from these two caves in Florida cannot record seasonal cycle in rainfall δ¹⁸O, but are suitable for paleoclimate reconstructions at inter-annual time scales.? Revised version of a paper presented at the 9th, Symposium of the European Society for Isotope Research (ESIR), 23 to 28 June 2007, Cluj-Napoca, Romania.      

双河油田VII油组油层的灰色关联评价

本文将双河油田Ⅶ油组油层视为-个灰色系统,以各油层的评价参数构造-个标准的最佳油层。由灰色关联分析方法计算各油层与最佳油层间的关联度,根据关联度的大小对各油层进行分类评价。评价结果与实际情况吻合甚好。     

基于碳酸盐岩缝洞系统的孔网模型构建与流动模拟研究

针对缝洞发育丰富的碳酸盐岩介质,基于孔隙网络构建理论,构建了两种不同的孔隙网络模型,并基于能量守恒与达西公式分别对两种模型进行流动模拟,通过与基于数字岩心流动模拟的结果对比,表明目前两种主要孔网建模的方法均不能准确描述缝洞特征显著的碳酸盐岩介质,但由于基于中轴线法构建的孔网中会产生数量众多的孔隙与吼道,因此该方法可以被用来表征缝洞介质,但需要从缝洞系统特征入手对其加以改进,以期在未来可以准确的描述缝洞型介质。     

洞桩法导洞开挖方案分析与优化

为了研究开挖方案对地表变形的影响,以北京17号线东大桥地铁车站为例,根据Peck公式采用地表沉降量和沉降槽宽度表征地表变形,采用Midas结合正交设计和回归分析研究采用对称开挖施工时,开挖顺序和开挖错距与地表变形的函数关系,最终得到最优开挖方案。结果表明：先开挖上层后开挖下层,先开挖边导洞后开挖中导洞时,沉降槽宽度最小;先开挖上层后开挖下层,上层采用先中后边,下层采用先边后中的开挖顺序时,地表最大沉降量最小。层间开挖顺序对地表最大沉降量的影响较为显著,上层开挖顺序是沉降槽宽度的主要影响因素。采用沉降槽宽度最小的开挖顺序,综合得出开挖错距与地表变形的函数关系;同时对沉降槽宽度进行优化,得到层间、上层、下层开挖错距依次为4、20、20 m。     

洞穴环境与洞穴旅游

喀斯特洞穴是喀斯特地貌的重要组成部分,在地质营力溶蚀,侵蚀和崩塌作用下形成。由于地质构造,岩性及气候的复杂性,地表、地下洞穴形态复杂,类型多样,构成高品位的旅游资源,具有重要开发价值。从洞穴的地质地貌,大气圈、生物圈、水文方面讨论,评价洞穴资源的价值。     

基于束波变换的叠后缝洞精细成像处理技术

碳酸盐岩储层中溶蚀孔洞和断裂的精确成像是地震油气勘探和开发的关键。以塔里木盆地塔河油田某区块奥陶系碳酸盐岩缝洞型储层为例,在精细的叠前预处理和逆时偏移的基础之上,利用束波变换技术,对研究区的地震数据进行了不同尺度的分解和重构,并对处理结果进行了对比分析。结果表明:束波变换技术可以有效改善溶蚀孔洞和断裂的成像效果,小尺度的束波变换适用于溶蚀孔洞信息的提取,而大尺度的束波变换更有利于增强断裂的清晰度,实际应用中应根据地质体的大小来选择合理的尺度参数。     

Apports de la colorimétrie et de la spectroradiométrie à la caractérisation in situ des peintures paléolithiques de la grotte Chauvet (Ardèche,France)

The colour of the Palaeolithic paintings on cave walls has been studied primarily in a qualitative way and, more rarely, from the physical angle. Our approach is based on the production of colorimetric measurements in caves, by means of the acquisition of energy radiance spectra with a portable spectroradiometer that can function without contact, several metres away from the decorated walls being studied, thus respecting the constraints of conservation. The colour of parietal works is an element that needs to be taken into account for their archaeological study and conservation. But observation is insufficient and only the measurement of colour makes it possible to compare distant works on rocky supports with different colourings and surface conditions.This article shows the methodology used, and it takes stock of the experience acquired in the research programme on the Chauvet Cave. It also attempts to show the benefits of taking spectroradiometric measurements on prehistoric artworks. However, the in-situ study of their colour cannot be a substitute for chemical and mineralogical analyses and the characterization of the materials, either sampled or in place. Its interest lies in its capacity for detecting even minimal changes in condition and composition. So our objective has been to establish comparisons between the graphic entities to identify the origins of the variations detected in their optical signatures. These variations can be linked to the nature of the colouring materials, but also to their position on the wall, a consequence of the application methods and sometimes also of later removals through taphonomic processes such as water run-off. Alterations (patinas) and coverings (notably veils of calcite or clay) have also been taken into account in our analysis of the data. Hence, we carried out experiments in calcification of surfaces to evaluate the case – quite frequent in caves – of calcite covering a coloured surface, outside of any other phenomenon of alteration. The first results lead us assume that it is possible to identify the signature of a veil of calcite on given colouring materials and also to present hypotheses about the nature of colouring materials covered by a veil of calcite.     

一种元卷积网络和持续学习融合的洞库类目标识别方法

洞库类目标是高价值识别目标,针对洞库类目标样本数据难以获得、样本内部数据相似度较高、人工设计识别特征方法局限性较大、普通深度网络需要海量数据等问题,提出了结合元学习和深度卷积网络的元-卷积网络（MCNN）,并融合持续学习理论的洞库类目标识别方法（MCNN-LLS）.首先结合深度卷积网络、元学习的理论建立元-卷积网络,该网络可利用旧知识指导新知识的训练,利用小样本数据即可训练得到识别能力较高的深度洞库模型;然后融合持续学习理论,建立持续学习系统（LLS）,设计专家审核模型判别深度洞库模型的识别结果,并引入潜在任务、模型异步更新等方法,达到模型持续学习、持续更新的效果.实验表明,本文方法所需样本数量少,对洞库类目标识别准确率高,且识别能力可随识别过程中新数据的积累逐步提高.      

Three-dimensional fluorescence spectral characteristics of dissolved organic carbon in cave drip waters and their responses to environment changes: Four cave systems as an example in Guizhou Province,China

Understanding the responses of fluorescence spectral characteristics of cave drip waters to modern environment and climate changes is key to the reconstructions of environmental and climatic changes using fluorescence spectral characteristics of speleothems. The fluorescence spectral characteristics of dissolved organic carbon （DOC） in four active cave systems were analyzed with a three-dimensional （3D） fluorescence spectral analysis method. We found that the fluorescence types of DOC were mainly of fulvic-like and protein-like fluorescences, both in soil waters and cave drip waters. The intensity of fulvic-like fluorescence was positively correlated with the concentrations of DOC, suggesting that the DOC of cave drip waters was derived from the overlying soil layer of a cave system. Compared with the other cave systems, the variation range of the excitation and emission wavelengths for fulvic-like fluorescence of cave drip waters in Liangfeng cave system that had forest vegetation was smaller and the excitation wavelength was longer, while its fluorescence intensity varied significantly. By contrast, the excitation and emission wavelengths and fluorescence intensity for that in Jiangjun cave system that had a scrub and tussock vegetation showed the most significant variation, while its excitation wavelength was shorter. This implies that the variation of vegetation overlying a cave appears to be a factor affecting the fluorescence spectral characteristics of cave drip waters.