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1.
准确确定Kaiser点是研究声发射测量地应力的关键.通过对模拟岩心的水泥块进行单轴受压破坏过程的声发射试验,得到了试件在试验过程中的应力-应变曲线、应力、声发射强度、声发射累积数与时间的关系图.分别对试样用突变点法、最大曲率法、双切线法、重加载法(抹录不尽现象、两次加载相减法)、多方面综合判定法以及声发射强度信号的统计分析法进行了分析.从不同的方面认识了试样的Kaiser点的特性,总结并分析了确定Kaiser点的方法以及各自的适应性,并进行了优选.研究表明,试验确定了试样的物理特性,各种方法都能从不同角度和机理上解释Kaiser点现象,综合判定法能相对更加全面、准确地确定Kaiser点.  相似文献   

2.
The selection of an optimal reclamation method is one of the most important portions of the surface mining design. There are many factors in this problem which seriously influence decision-making. The fuzzy set theory was applied due to the effect of uncertain parameters involved in the decision-making process. Therefore, the fuzzy multi-attribute decision-making method was proposed. The aim of this study is to use the fuzzy technique for order preference by similarity to ideal solution method for ranking the optimal post-mining land-use and the fuzzy analytic hierarchy process method in order to determine the weights of each criterion. This approach is applied to the surface coal mine by employing 28 criteria which influence the decision-making procedure. The TOPSIS and AHP methods have been the most used methods of mining decision-making and demonstrated their ability to make critical decisions. By evaluating the alternatives and considering effective criteria with proposed methods, agriculture is the optimal post-mining land-use.  相似文献   

3.
Dover is located at the mouth of a narrow valley that forms the only significant break in almost 20 km of chalk cliffs along the Kentish Channel coast. This, together with the close proximity of the Continent, has ensured the site's standing as a port since pre-Roman times. However, little is known of the sequence of events associated with the transformation of the area since the later prehistoric period, and in particular the evolution of the harbour which has had at least four different locations. Work to regenerate central Dover has however provided opportunities to address these issues and we report here on geological evidence for harbour development and coastal change from the middle Holocene period to the present day.Foraminifera and ostracods recovered from boreholes and excavations in the town centre allow patterns of sedimentation to be identified and linked to archaeological finds such as the Dover Bronze Age Boat and Roman harbour installations. Radiocarbon dating, and archaeological spot-dating provides a chronological framework for these changes. In particular the later Prehistoric environments and their transformation to estuarine environments by the time of Roman activity in the area are examined (including the role of sea level change and coastal erosion). The history of sedimentation within the Roman harbour and the role played by human activity in accelerating sedimentation in the old valley mouth is also considered. Finally dune formation across former estuarine habitats is documented in the Anglo-Saxon period creating the topographic template on which the modern town is based.  相似文献   

4.
The modern Tianshan Mountains and their surrounding basins have mainly been shaped by the far field effects of the Cenozoic India-Asia collision. However, precollision topographic evolution of the Tianshan Mountains and its impacts on the Junggar and Turpan Basins remain unclear due to the scarcity of data. Detrital zircon U-Pb dating of 14 new and 23 published samples from Permian to Neogene strata in the northern Western Tianshan Mountains, northern and southern Bogda Mountains and Central Turpan Basin, are combined with sedimentary characteristics (lithofacies, petrofacies and paleocurrent data) to investigate the temporal and spatial changes in sediment provenances. Based on the age characteristics of the source rocks in the Tianshan Mountains, the detrital zircons are divided into three groups: pre-Carboniferous zircons, mainly from the Central Tianshan Mountains; Carboniferous to Permian zircons, mainly from the North Tianshan and Bogda Mountains; and Mesozoic zircons, mainly from syn-depositional volcanic activity. The topographic evolution of the Tianshan Mountains and their relation to the Junggar and Turpan Basins can be generally divided into six stages. (1) Positive-relief Tianshan and Bogda Mountains and a rifted marine basin formed during the Early Permian to early Middle Permian following late Carboniferous orogenesis, as evidenced by interbedded alluvial fan conglomerates and postcollisional extension-related volcanic rocks along the basin margins, by marine deposits far from the basin margins and by the predominance of Carboniferous to Permian detrital zircons. (2) Fluvial to lacustrine deposits in the modern southern Junggar and Turpan Basins are characterized by abundant pre-Carboniferous zircons and consistently northward-flowing paleocurrents, indicating the submergence of the Bogda Mountains and a contiguous Junggar-Turpan continental depression basin during the late Middle Permian to the Triassic. (3) The Bogda Mountains began to uplift in the Early Jurassic, resulting in opposing paleocurrent directions, a sudden increase in sedimentary lithic detritus and the dominance of Carboniferous to Permian detrital zircons along the southern and northern margins of this range. (4) In contrast to the uplift of the Bogda Mountains, the other parts of the Tianshan Mountains experienced gradual peneplanation from the Early Jurassic to the Middle Jurassic, as confirmed by widespread fluvial to lacustrine deposits, even inside the modern Tianshan Mountains, and by the dominance of pre-Carboniferous detrital zircons. (5) The dominance of Carboniferous to Permian zircons in the southern Junggar Basin suggests the West Tianshan Mountains were uplifted during the Late Jurassic, while the dominance of pre-Carboniferous zircons in the Central Turpan Basin indicates continuous peneplanation in the Eastern Tianshan Mountains. (6) The initial shape of the Tianshan Mountains-Junggar Basin-Turpan Basin system was constructed in the Late Jurassic but was modified in the Cenozoic by the India-Asia collision, resulting in much higher Western Tianshan and Bogda Mountains, low Eastern Tianshan Mountains and well-developed foreland basins. These Cenozoic changes were recorded by the rapid cooling of apatites, the dominance of Carboniferous to Permian zircons in the southern Junggar Basin and northern Turpan Basin, and the dominance of pre-Carboniferous zircons in the Central Turpan Basin.  相似文献   

5.
本文简单总结与介绍了怀柔—密云境内,石城断裂的规模、性质与活动性。初步认为该断裂属脆韧性剪切带,与云蒙山岩体上侵有关,早期压性,晚期显张性,属非全新世活动断裂,对工程影响程度低。  相似文献   

6.
The commodification of culture has received much attention in social and cultural geography. Based on empirical research in Lijiang, a World Heritage site in China, this paper contributes to an understanding of commodification through a focus on selling ethnic music to tourists. Drawing upon a theoretical framework of tourism commodification and the cultural politics of music, I argue that the commodification of music is embedded in a temporal process in which culture, economy, and politics synthesize to shape place making and identity building. This paper presents three major findings: (1) commodification sustains discourses of identity building and cultural revival that in turn serve to justify the pursuit of profit; (2) commodification is variegated over time and across space; and (3) commodification provides the conditions for local musicians to increase their capacity to produce local narratives of music. By demonstrating the commodification of ethnic music and the cultural politics of musical space in Lijiang, this paper calls for an interconnection of economy, culture, and politics in understanding the materiality of music.  相似文献   

7.
The effectiveness of two geotechnical investigation tools—the piezocone and the dilatometer—to characterize the soils forming the shallowest deposits of the upper quaternary basin of the Venice lagoon soil is examined in this study. For this purpose, the results of a comprehensive site and laboratory investigation carried out recently over a small lagoon area—the Malamocco Test Site—are used to evaluate the applicability of the most widely used charts or correlative equations to characterize soil profile and estimate the main geotechnical properties of these soils, when applied to the interpretation of CPTU and DMT results. The particular interest of this site—apart from its unquestionable historical relevance—is the presence, apparently without any regular pattern in depth and site, of a predominantly silty fraction combined with clay and/or sand, thus forming an erratic interbedding of various types of sediments. This case represents therefore the opposite condition of that which has been normally utilized in the past to calibrate the two devices, namely the presence of particularly homogeneous natural deposits or artificially sedimented homogeneous layers of sand or clay. The Malamocco Test Site may therefore be considered as test benchmark for the applicability of the two devices to characterize highly heterogeneous silty deposits.  相似文献   

8.
地质工程在链子崖危岩治理中的应用   总被引:1,自引:0,他引:1  
面对链子崖浩翰的地质资料,往往使传统的设计人员无从下“海”而地质人员确实不也不能为力按照从如此众多的地质中凝缩出几个所谓的“参数”供设计人员使用,作者深感,从未遇到一个如此要求地质,设计与施工有结合,并以“地质”为主线纵贯始终,以“设计”为桥梁沟通“地质”与“施工”的工程。这就是地质工程。  相似文献   

9.
The National Water Act (Act 36 of 1998) in South Africa recognizes basic human water requirements as well as the need to sustain the country's freshwater and estuarine ecosystems in a healthy condition for present as well as future generations. In this Act, provision is made for a water reserve to be estimated prior to the authorization of water use (e.g., for agriculture, large volume residential and industrial uses) through licensing. This reserve is the water required to satisfy basic human needs (i.e., 25 1 person?1 d?1) and to protect aquatic ecosystems to ensure present and future sustainable use of the resource. This led the Departments of Water Affairs and Forestry and estuarine scientists throughout South Africa to develop a method to determine the freshwater inflow requirements of estuaries. The method includes documenting the geographical boundaries of the estuary and determining estuarine health by comparing the present state of the estuary with a predicted reference condition with the use of an Estuarine Health Index. The importance of the estuary as an ecosystem is taken from a national rating system and together with the present health is used to set an Ecological Reserve Category for the estuary. This category represents the level of protections afforded to an estuary. Freshwater is then reserved to maintain the estuary in that Ecological Reserve Category. The Reserve, the quantity and quality of freshwater required for the estuary, is determined using an approach where realistic future river runoff scenarios are assessed, together with data for present state and reference conditions, to evaluate the extent to which abiotic and biotic conditions within an estuary are likely to vary with changes in river inflow. Results from these evaluations are used to select an acceptable river flow scenario that represents the highest reduction in freshwater inflow that will still protect the aquatic ecosystem of the estuary and keep it in the desired Ecological Reserve Category. The application of the Reserve methodology to the Mtata estuary is described.  相似文献   

10.
赵珊茸  徐畅  张国庆  李坤 《地球科学》2013,38(2):211-217
综合分析了石英、石榴子石、橄榄石、锆石、红柱石的各不同结晶学意义的晶面腐蚀像特点,总结了晶面腐蚀像与晶面对称性及晶面结构特点之间的关系.腐蚀像不仅可以揭示晶面及晶体的对称性,还可以揭示晶面的结晶学意义,即同一晶体上的不同结晶学意义的晶面,尽管对称性相同,也具有不同的腐蚀像;不同晶体之间的具有相同对称性的晶面可能会有相同的腐蚀像;腐蚀像类似于一种宏观晶体形态,主要与晶面的对称性有关,与晶面上原子、离子排列的结构细节关系不大;同一晶体的同一晶面在不同的腐蚀剂中所得的腐蚀像也可能完全不同;有些晶面的腐蚀像可以用晶体生长形态的常见晶面与被腐蚀面的交棱来解释.该研究在揭示晶体溶解形态机理、将溶解形态与晶体生长形态对比、用溶解形态来反映晶体曾经经历的酸-碱环境等方面具有理论与实际意义.   相似文献   

11.
In order to consider a counterplan to preserve an ancient royal tomb in Kongju, Korea, the deformation of the wall structure, the atmospheric temperature in the tomb, and the groundwater level have been monitored. The long-term measurement of biaxial tilting of the tomb walls revealed that the brick-built subsurface opening had been subjected to severe structural instability. The measured deformation of the tomb was consistent with the displacement of soil around the tomb calculated using a numerical analysis. The instability of the tomb structure is closely related to the rainy season as the deformations measured are several times that in the dry season. A sudden change of temperature inside the tomb exerted an influence on the deformation of the tomb structure as well. It is suggested that the excavation be restored for tourists, the quicklime layer for preventing groundwater infiltration is reinforced, and a constant temperature is kept inside the tomb. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

12.
韦兴  黄礼华 《探矿工程》2003,30(2):15-17
介绍了柳钢围炉3号板坯主厂房沉降柱基灌浆加固和因加固引起的柱基抬升、倾斜及倾斜柱子纠偏扶正施工技术,并总结了经验教训。  相似文献   

13.
Mount Pinatubo volcano erupted in June 1991 in the main island of Luzon belonging to the Philippines archipelago. Huge economic losses and population exodus have followed. This major crisis has been relayed with other crises due to rain-fed lahars which have been supplied with eruption deposits. These lahars have occurred every year since 1991 during the rainy season. They will probably last until 2005. After a brief presentation of the Philippine official response system to disasters, this paper draws up a critical analysis of the different kinds of institutional and social responses deployed to manage the different crisis and post-crisis phases of this event. Based on three viewpoints: from population, media and other actors, this analysis attempts to point out the strengths and weaknesses of the official management system, especially by studying the efficiency and the range of the solutions taken. So, it appears that the management of the June 1991 main crisis (eruption) was a success. On the other hand, difficulties have occurred with lahars risk management. Indeed, these lahars have obliged the authorities to protect and relocate thousands of people. In spite of persistent problems, the management system (monitoring/warning/evacuation) of lahar crises improves year after year. Failures appear especially within the rehabilitation program (protection/rehousing). Many direct (lack of means, preparedness, coordination, dialog, etc.) and indirect (politico-administrative, socio-economic, cultural contexts) factors come together to lock the wheels of the institutional response system. They defer the socio-economic start of this vital northern Philippines area. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

14.
生态-水文中无线传感器网络应用研究   总被引:2,自引:0,他引:2  
无线传感器技术的成熟推动了无线传感器网络在环境监测中的广泛应用.但在高寒高海拔极端恶劣环境下,开展无线传感器网络应用的较少.从生态-水文研究出发,选取关注度较高的黑河流域一级支流马粪沟子流域为研究区域,配合现有定点观测系统,提出一种适宜生态-水文模型需要的面上密集数据观测的无线传感器网络系统框架.重点讨论了无线传感器观测网络的实现方案、观测点的选取、传感器节点的部署、节点的网络拓扑构成以及传感器网络的软、硬件组成,实现了已经部署的无线传感器观测网络的数据自动采集、自动传输、自动处理及数据可视化展示等,总结并分析了无线传感器网络在生态-水文应用与研究中存在的问题和经验,并对应用前景进行了展望.  相似文献   

15.
Studies at the macro-scale have indicated that many remote rural areas are for the first time in over a century experiencing population growth while metropolitan areas are losing population. In this paper theories of counterurbanisation directed towards explaining the redistribution of population at a national or regional scale are criticised and a more localised research framework is proposed. Such a framework is constructed for the examination of migration into West Cornwall. Results from a postal questionnaire survey of seven study areas in West Cornwall are used to illustrate differences between three population subgroups, namely, return migrants, non-return migrants and non-migrants. Clear differences emerge not only between the population subgroups but between the study areas as well. In conclusion, it is suggested that this middle-range approach should be adopted more widely in order to gain greater insight into the counterurbanisation process and to increase the prospect of relating macro-processes to local trends and human experience.  相似文献   

16.
Police, politics, and the right to the city   总被引:1,自引:0,他引:1  
Mustafa Dikeç 《GeoJournal》2002,58(2-3):91-98
Space and spatiality have recently been at the core of debates concerning the political possibilities of the city. The arguments advanced in this paper might be seen as an attempt to contribute to these debates through a reflection on the spatiality of (in) justice, politics, and the right to the city. The case of French urban policy, with its focus on distressed urban areas, and the `suburban problem' in France are used as examples to make arguments more concrete.  相似文献   

17.
A relationship is drawn between the surface features of the moon and the surface features of the earth. The comparison implies crustal expansion and digestion where the crust fractures and thins in ocean basins, the old fractured lighter crust, being part of the ancient continuous crust, forms the continents. The continents are formed of lighter chemical fractions which float on the heavier more basic younger crust. A simple mechanical system is given to explain the processes involved and surface evidence is given to strengthen the argument. The paper is an introduction to a new concept in global geology, — the process of crater tectonics.  相似文献   

18.
Barodesy is a new framework for constitutive modelling of soils. The actual version uses a constant value of the coefficient of earth pressure at rest K 0, which contradicts experimental findings. A straightforward modification is presented here to remove this shortcoming. The calibration of the material parameters remains as simple as in the original model.  相似文献   

19.
The true third-law entropies of many minerals are frequently quite different from those values derived from calorimetric measurements. The discrepancy can usually be attributed to neglected residual or unextracted entropies related either to site-mixing and molecular disorders or to the lack of significant magnetic ordering at those temperatures reached by the heat capacity measurements. A literature review indicates that many silicates present site-mixing and vacancies in one or several of their crystallographic sites. The effect on entropy is well known in feldspars, but residual entropies of similar or greater magnitudes are also present in many amphiboles, micas, chlorites, zeolites, scapolites, feldspathoids, and other silicates. Less conspicuously, disorder in water molecules or hydrogen bonding may be responsible for yet another frequently overlooked entropy contribution. Unextracted entropy results from limited heat capacity measurements so that magnetic ordering effects to be expected in minerals with transition metals are either not registered or only incompletely recorded. In some cases, significant magnetic ordering probably only takes place at temperatures well below 15 K.The discussion in this paper centers on the causes resulting in discrepancies between calorimetric and third-law entropies. A set of tables reproduces the crystallographic information for most important rock-forming silicates and indicates the entropy contribution arising from site-mixing and vacancies, and possible magnetic ordering in those substances with transition metals. In addition, most elements appear in several isotopic forms, and it is this effect that gives rise to isotopic site-mixing and thus to another configurational entropy. It can on the whole be neglected. A discussion centered on the system fayalite-iron oxides (wüstite, hematite, magnetite) indicates the uncertainties involved in deriving third-law entropies from either equilibrium data or calorimetric investigations, which is especially relevant when dealing with substances presenting vacancies (wüstite), transition metals, and the possibility of magnetic ordering. The published entropies of many minerals are probably only approximations to true third-law values and should be checked against structural and magnetic information.  相似文献   

20.
危地马拉目前已成为仅次于缅甸的第二大翡翠原料供应地。这两个产地翡翠辨别的需求愈发迫切,且应用意义较大。采用显微镜观察、电子探针分析及背散射电子照相获得危地马拉蓝水料翡翠的矿物成分及结构构造特征,结合两产地翡翠产出的大地构造环境、自然地理环境、原石特征与矿物成分特征等进行对比分析。总体上,危地马拉翡翠次生原石有一定的磨圆,呈次棱角状,“皮”(风化皮)厚度较薄,较少出现翻砂现象,由“皮”向里,极少甚至几乎不存在“红雾”。相对地,缅甸翡翠次生原石发育显著的球状风化,原石通常有较好的磨圆度,棱角状不明显,“皮”厚度可达数厘米,用手压磨有显著的翻砂现象, “皮”“肉”之间偶可见“红雾”。硬玉与绿辉石成分判别图显示危地马拉翡翠中硬玉和绿辉石呈相对富Ca、贫Na的特征,而缅甸翡翠中硬玉和绿辉石整体呈相对贫Ca、富Na的特征。在Fe含量上,危地马拉翡翠中硬玉的Fe含量较缅甸翡翠中硬玉的Fe含量偏低,而危地马拉翡翠中绿辉石的Fe含量较缅甸翡翠中绿辉石的Fe含量偏高。对翡翠外观特征的充分对比和对判别图的综合分析可应用于实际中翡翠产地的区分。  相似文献   

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