塔北油区岩石声发射全过程曲线类型及特征

本文讨论了岩石试样在加载全过程中的声发射特征、不同岩石声发射全过程曲线的分类以及类型的确定方法;对新疆塔里木盆地北部油区井下和地表试样进行了统计、分类,确定出该油区泥岩、砂岩声发射全过程曲线存在Ⅰ、Ⅲ两种类型;白云岩、灰岩、玄武岩声发射全过程曲线具有Ⅰ型特征。      

21世纪黄河下游防洪减灾对策

黄河是受人类活动强烈影响的河流,随着人类活动对流域环境的影响日趋增强,进入黄河下游的水沙条件发生了重大改变,防洪出现了许多新情况、新问题。黄河水资源进一步开发利用,下游牵断流及小水时间逐年延长,黄河将无有效输沙水量,如果来沙不能控制,现行河道的行洪能力和寿命将始终是中国的忧患。小浪底水库２００１年投入运用后,对黄河下游又将强烈堆积。２１世纪社会经济发展对黄河下游防洪减灾提出了更高要求,根据多年对黄     

关于中国煤层瓦斯区域分布的几点认识

据１９９４￣１９９６年连续３年的统计,全国煤矿瓦斯灾害伤亡人数占煤矿伤亡总人数的４０％以上,瓦斯涌出规律、瓦斯涌出量预测、瓦斯突出预测仍是煤矿安全技术的难题,在加强对瓦斯灾害综合治理的同时,把瓦斯作为煤层气资源积极进行开发利用,是当前的研究方向,瓦斯区域分布规律研究可以概括为建立在煤层瓦斯生成条件、保存条件基础上的高斯赋存量,高瓦斯涌出量,低瓦斯赋存量,低瓦斯涌出量区域分布规律研究;建立在高瓦斯赋     

初冬季节青藏高原清水河地区甲烷排放率变化(英)

As the globally largest area covered by high altitudinal permafrost, the Qinghai-Tibet Plateau may contribute substantially to atmospheric CH4 budget when global warming. Preliminary observations on CH4 emission at Qingshuihe from November 5 to 14, 1995 show that alpine grassland may be a small source for atmospheric CH4 during early winter. The emission rates of CH4 from moist grassland surface varied from-16. 1 to 23. 9 μg. m-2h-1, with an average of 1. 82 μg. m-2h-1. Emission rates of CH4 from water surface of Qingshuihe River were from -21. 0 to 37. 1 μg. m-2h-1, with an average of 1. 56 μg. m-2h-1. The emission rates of CH at 30 to 200 cm in depth ranged from-69. 0 to 36. 0 μg. m-2h-1, with the average rate at these depths varying from -2. 15 to 2. 04 μg' m-2h-1. The mean emission rates of CH4 in the active layer and permafrost indicate the lower part of active layer tends to release CH4, CH4 is absorbed at low rates in the middle section and in the vicinity of permafrost table, and net fluxes of CH4 is emitted from the soils in the upper part. During the observation periods, the methane concentrations in static chambers and emission rates of grassland and water surface displayed noticeable diurnal variations. The water/ice content may play important role in the spatial variations of methane emission rates. The emission rates of methane is weakly correlated with the ground temperatures at sampling depths and air temperatures. The observed emission rates of methane from the comparatively dry and sandy grassland soils are quite low compared with that observed in the permafrost regions in the high latitudes.     

阳城煤矿瓦斯地质规律研究

运用沉积学、构造地质学、煤地质学、数学分析等相关学科和方法,综合分析瓦斯涌出量的地质构造、顶底板岩性、上覆基岩厚度等地质因素,对阳城地区瓦斯含量、涌出量进行量化预测,并作出其全井田瓦斯含量、涌出量的等值线图。研究表明,阳城井田属低瓦斯矿井,瓦斯含量的变化主要与煤层埋深有关,随着煤层上覆基岩厚度以及煤层埋深的增高,瓦斯含量与涌出量在区内由北向南有增高趋势。     

Implementing low-cost landslide risk reduction: a pilot study in unplanned housing areas of the Caribbean

Landslides pose a serious physical and environmental threat to vulnerable communities living in areas of unplanned housing on steep slopes in the Caribbean. Some of these communities have, in the past, had to be relocated, at costs of millions of dollars, because of major slides triggered by tropical storm rainfall. Even so, evidence shows that: (1) risk reduction is a marginal activity; (2) there has been minimal uptake of hazard maps and vulnerability assessments and (3) there is little on-the-ground delivery of construction for risk reduction. This article directly addresses these issues by developing a low-cost approach to the identification of the potential pore pressure changes that trigger such slides we seek to address these three commentaries directly. A complex 45–60° slope site in St Lucia, West Indies was selected as a pilot for a modelling approach that uses numerical models (FLAC and CHASM) to verify the need for surface water management to effectively reduce landslide risk. Following the model confirmation, a series of drains were designed and constructed at the site. Post-construction evidence indicates the methodology to be sound, in that the site was stable in subsequent 1-in-1 to 1-in-4 year rainfall events. A critical feature of the approach is that it is community-based from data acquisition through to community members participating in construction.     

Electromagnetic emissions during dilating fracture of a rock

A lot of experiments on electromagnetic emissions (EMEs) have been reported under axial compressive fracture, shear fracture, indentation fracture and stick–slip (friction) in lab and blasting in situ, but there are rare reports on the in-lab experimental work on EMEs during dilating fracture of a rock which is helpful in studying and understanding EMEs related to slow earthquakes and the earthquakes due to volcanic activities and water level changes of reservoirs. Therefore, in the present paper in order to check whether there are detectable EMEs during dilating fracture of a rock in lab, dilating fracture experiments were conducted. The dry cuboid specimens of initially intact granodiorite and limestone were tested inside magnetic field free space (MFFS) at room temperature. We arranged evenly 20 EME antennas whose resonance frequencies range from 2.5 kHz to 540 kHz close to rock specimens. Our experimental results strongly indicate that detectable EMEs could generate during dilating fracture of a rock. They were recorded only associated with some but not all phases of fracture. Their waveforms often took on the trend that a peak arrived at first and then attenuated sharply and followed by a series of low-amplitude oscillations. The electromagnetic (EM) signals after eliminating the effects of EME antennae via deconvolution had the maximum peak-to-peak amplitudes of about 80.0 mV and 40.5 mV for granodiorite and limestone, respectively. Their main spectral components often concentrated in the band of several kHz to ∼60 kHz and of several kHz to ∼280 kHz. The emission of electrons and charged particles from fracture surfaces and/or micro-fracture electrification could be possible mechanisms for our experimental results.     

基于小波包变换的不同强度煤样的声发射特性

为了研究在单轴压缩下不同强度煤样的声发射特征,利用RMT-150C型岩石力学伺服试验系统和CDAE-1型声发射检测仪,对硬煤、中硬煤和软煤煤样进行实验研究。为了解决煤样在声发射实验中存在的各种信号干扰和信号处理方面的问题,运用小波包变换对煤样的声发射信号进行了分解、去噪和重构。研究结果表明：经过处理之后的声发射信号能够更清晰地反映硬煤、中硬煤和软煤煤样在单轴压缩下失稳破坏的变化特征。软煤、中硬煤和硬煤的声发射信号特征各不相同,随着煤样强度的增加,煤样失稳破坏时声发射累计能量和累计计数逐渐减小,煤样在受力过程中声发射能量和计数的峰值也逐渐减小,并且在峰值处释放的能量也逐渐减小。     

A Review of the Scientific Assessment and Research on Household Carbon Emission

Household consumption represents an important proportion of all energy consumption,and it is an important source of CO₂ emission. But household consumption and carbon emissions are often overlooked in climate change policies and measures. Through literature review, the research status of household consumption and carbon emissions were reviewed. On this basis, the main aspects and directions of the research are summarized and the main research of household carbon emissions should focus on three aspects in the future: ①The impact of income, consumption levels and other factors on household carbon emission; ②The relationship between direct and indirect carbon emissions of household carbon emission; ③The structure and source of household carbon emission. In future research, there are four issues which need in-depth study: ①Index and models study of household carbon emissions;②Impact of demographic change on household carbon emissions; ③The path of how to achieve sustainable and green urban lifestyle;④The relevant policy research of household carbon emissions.     

Applied geophysics for cover thickness mapping in the southern Thomson Orogen

Abstract

Potentially mineralised Paleozoic basement rocks in the southern Thomson Orogen region of southern Queensland and northern New South Wales are covered by varying thicknesses of Mesozoic to Cenozoic sediments. To assess cover thickness and methods for estimating depth to basement, we collected new airborne electromagnetic (AEM), seismic refraction, seismic reflection and audio-frequency magnetotelluric data and combined these with new depth to magnetic basement models from airborne magnetic line data and ground gravity data along selected transects. The results of these investigations over two borehole sites, GSQ Eulo 1 and GSQ Eulo 2, show that cover thickness can be reliably assessed to within the confidence limits of the various techniques, but that caveats exist regarding the application of each of the disciplines. These techniques are part of a rapid-deployment explorers’ toolbox of geophysical techniques that have been tested at two sites in Australia, the Stavely region of western Victoria, and now the southern Thomson Orogen in northern New South Wales and southern Queensland. The results shown here demonstrate that AEM and ground geophysics, and to a lesser extent depth to magnetic source modelling, can produce reliable results when applied to the common exploration problem of determining cover thickness. The results demonstrate that portable seismic systems, designed for geotechnical site investigations, are capable of imaging basement below 300 m of unlithified Eromanga Basin cover as refraction and reflection data. The results of all methods provide much information about the nature of the basement–cover interface and basement at borehole sites in the southern Thomson Orogen, in that the basement is usually weathered, the interface has paleotopography, and it can be recognised by its density, natural gamma, magnetic susceptibility and electrical conductivity contrasts.