Comparative Study on Calculation Methods of Blasting Vibration Velocity

Due to the extreme complexities in rock blasting and difficulties in theoretical or numerical analysis, and the enormous consumption of explosives in mining and construction operations, empirical or semi-empirical formulae for blasting vibration velocity (BVV) were obtained from observations and measurements in field blast tests and are still widely used all over the world. This paper investigates the fitting degree and characteristics of several calculation methods for BVV based on 34 sets of data samples from 27 projects belonging to 4 types. The results indicate that both the cube-root scaling formula and the square-root scaling formula have relatively good fitting degree, while the multiple regression analysis can give the best fitting outcome if the sample space satisfies certain requirements. Whether the cube-root scaling formula or the square-root scaling formula is chosen to analyze the relationship between BVV and scaled distance depends on the average scaled distance under cubic-root scaling. If the average scaled distance is over 0.1, the cube-root scaling formula should be used; otherwise, the square-root scaling formula should be used. Bigger samples integrated from data samples of different projects but in the same type were then analyzed to get the empirical relations for different types of projects. The correlation coefficients of these relations are quite good, thus these relations can be used for reference in other similar projects. This paper then discusses the physical meanings of parameters in different formulae, sample selection and parameter choice for BVV. It suggests that the current calculation methods for explosive charge, blasting-to-monitoring distance and scaled distance need to be improved. It also concludes that the integrated BVV from velocity components in three-dimensions is more reasonable on a theoretical basis. It can yield good results in predicting the blasting vibration, and should be used as widely as possible.     

The controlling effect of thick-hard igneous rock on pressure relief gas drainage and dynamic disasters in outburst coal seams

Intrusive igneous rock is usually found in the overlying strata above mining stopes, and its occurrence, lithology, and distribution play important roles in coal mining safety. Of the numerous coal mine disasters in China, a large number have been caused by magma intrusion. Magmatic activity is intense and widely distributed in the Haizi Coal Mine which has suffered eleven coal and gas outburst accidents and one water inrush accident under a thick-hard igneous rock with 120-m-thick. Based on theoretical analysis, laboratory testing and field observations, we found that under the effect of thermal evolution and entrapment of the igneous rock, the coal pore structure developed, the gas adsorption capacity was enhanced, and the risk of gas outburst increased. The igneous rock, as the main key stratum, will not subside or break for a long time after mining. The closing time of fractures and separations is also prolonged and provides good conditions for gas drainage. The distant penetration borehole for draining pressure relief gas is proposed which can ensure effective gas drainage and reduce the number of rock laneways. However, with the continuous mining of a large area, the igneous rock could suddenly break, instantly releasing a tremendous amount of elastic strain energy, which will easily induce the occurrence of complex dynamic disasters, such as rock bursts, water inrush, gas outbursts, and surface subsidence. Based on the cause analysis of dynamic disasters, a reasonable goaf filling height is proposed for fully eliminating mine disasters under the special geological condition.     

富县地区延长组储层特征及其非均质性

富县地区延长组主要发育三角洲和湖泊沉积体系,其中分流河道和水下分流河道骨架砂体呈北东-南西向条带状展布,纵向上连续性好,是主要储集体。岩性主要为灰色-灰绿色细-中粒岩屑长石砂岩和长石砂岩,填隙物主要是胶结物,以方解石、绿泥石膜为主。主要受沉积和成岩作用两个因素控制,储层物性较差,纵向上和横向上非均质性均较强。层内非均质性主要影响因素为垂向上粒度分布的韵律性、层理构造、层内夹层和层内裂缝等,层内渗透率非均质参数表现为中等-强的非均质性;分层系数和砂岩密度长8、长6、长3和长2油层组较大,长7和长4+5油层组较小;层间渗透率非均质参数长8、长6及长3较大,为强非均质性,长7和长2较小,非均质性相对较弱,为中等非均质性。     

煤层气储层注入/压降试井可靠性判识方法探讨

注入/压降试井作为获取煤储层参数的一个重要手段,近年来获得了广泛的应用.但由于施工设计不合理、现场操作不规范、模型选择不正确等问题,导致测试过程异常和测试结果失真,针对这些问题提出了几种判识方法:利用储层压力值与末点压力值的关系来检验测试结果是否可靠;利用井储系数计算值与实测值的关系及双对数曲线上出现的异常点来检验封隔器是否密封及井下关井是否成功.为了提高注入/压降试井测试过程和结果的可靠性,建议采用推荐的检验方法对试井资料及解释结果进行分析判断,以便合理指导后续勘探开发工作.     

Soil erosion monitoring and its implication in a limestone land suffering from rocky desertification in the Huajiang Canyon, Guizhou, Southwest China

Over the past decades, the vast limestone mountain areas in southwestern China have suffered greatly from karst rocky desertification (KRD), which is a unique type of desertification caused by irrational land-use practices and has drawn increasing attention of international academic community. Characterizing soil erosion in this region is the key to understanding the escalating KRD problem and finding solution to it. The authors applied leveling method to study soil erosion process in the Huajiang Karst Canyon area between 1999 and 2003, and tried to relate it to KRD expansion. The monitoring data indicate that soil in the study area was losing at an alarming rate, which is much higher than soil formation rate and has already resulted in severe KRD problem. Soil loss under different land-use conditions varied greatly during the monitoring period. The highest soil erosion rate occurred in bare and newly abandoned cropland, followed by sparse grass land, forest land, and dense grass land. In addition, soil erosion could be significantly different under different micro-topographic conditions. Because soil erosion rate in the studied karst mountain areas is surprisingly high, it is urgent to take quick actions to fight against the ongoing KRD problems in Southwest China before an irreversible situation occurs. However, the traditional way to combat KRD by abandoning current cropland needs to be carefully reconsidered, since a bare newly abandoned cropland may suffer more from rapid soil loss than before.     

一种分析台风路径预报误差的新方法

台风路径预报误差应包括距离误差和方向误差两个方面,而在以往的业务应用和科学研究中偏向于只考虑对应时刻预报和观测位置点间的距离误差。本文对评估台风路径误差的方法进行了改进,在距离误差基础上建立了一种新的表征台风路径误差的方法——多因子误差法。本文以中国气象局整编的热带气旋最佳路径数据为标准,对2008和2009年中国气象局、美国台风联合预警中心和日本气象厅预报的西北太平洋热带气旋路径,采用新的表征热带气旋路径预报误差的多因子误差法进行分析,并与普遍采用的距离误差法进行对比,结果表明:多因子误差分析方法和距离误差分析方法存在比较明显的差异,多因子误差法优势比较明显。本文是对更科学的台风路径预报误差评定方法的有益探索,有一定的参考价值。     

交通行业应急管理空间数据库研制

建立交通行业应急管理空间数据库,可为重大突发自然灾害事件时交通应急提供有效的数据支持。本文面向重大突发自然灾害事件的应急管理,从功能需求上对交通行业应急管理所需数据进行了分类,将空间数据库划分为文件数据库、应急专题数据库和元数据库3个子库,采用Oracle,ArcSDE和文件编目管理相结合的方式进行管理,并建立了交通行业应急管理空间数据库。最后以公路重大自然灾害监测评估为例,说明了该数据库对灾害应急中所开展的快速监测评估分析的应用价值。     

中国荒漠主要植物群落调查的意义、现状及方案

荒漠是中国北方的重要生态系统,约占中国陆地总面积的1/5。植物群落是荒漠生态系统的有机组成部分,是构建中国北方绿色生态屏障、实施国家重大生态工程、落实“一带一路”倡议和建设生态文明的重要基础资源,在国家社会、生态和经济活动中发挥着重要作用。以塔里木-准噶尔盆地荒漠区、青藏高原高寒荒漠区、阿拉善高原-河西走廊荒漠区、西鄂尔多斯高原-阴山北麓荒漠区、内蒙古中东部半干旱荒漠区为主要调查区域,共布设2 300个调查点,以查清中国北方荒漠植物群落类型、种类组成、群落学特性、空间分布、利用现状及生境特征,测定荒漠植物DNA条形码。获取荒漠植物样本8 300份,生境数据5万份,植物DNA条形码2 300份。以此为基础,编写中国荒漠植物群落类型、特征与现状调查报告,编制荒漠植物群落类型分布图集,建立中国荒漠植物群落资源监测体系。通过构建荒漠植物群落的数据库,利用国家科技基础条件平台,实现荒漠植物群落特征数据的联网共享,可为中国荒漠治理、植物资源保护与可持续利用提供数据支撑。     

引入影像重构的边缘检测算子性能评估方法

首先,利用待评估边缘检测算子进行边缘检测;然后,根据检测边缘支撑区融合边缘位置信息与灰度信息,并利用改进的灰度反距离分区加权均值法实现影像重构;最后,设计反映原始影像与重构影像之间特征相似度的性能评估综合指标,完成边缘检测算子的性能评估。实验结果表明,该评估方法的结论与人工判读的结果相吻合,并且不需要先验参考信息,有一定的工程应用性。