Use of rock classification to estimate roof caving span in oblong workings     

P. R. Sheorey 《Geotechnical and Geological Engineering》1984,2(2):133-140

Summary Indian coal measures have widely varying caving characteristics. The maximum roof span of a longwall or depillaring panel at the time of nether roof collapse is shown to have a direct relation withRQD from a study of 12 case histories. A similar relation between maximum unsupported span of openings and rock mass quality as defined by theQ-system was also demonstrated. A simple nomogram is presented to predict the face advance required to cause roof collapse when theRQD or rock mass quality is known.  相似文献   

Roof bolting in underground mining: a state-of-the-art review   总被引：1，自引：1，他引：1  

Syd S. Peng  D. H. Y. Tang 《Geotechnical and Geological Engineering》1984,2(1):1-42

Conclusions With continuing investigations and developments, roof bolting today can in most cases successfully reinforce the mine roof in underground mining. In order to cope with the increasing use of roof bolts, efforts should be made to maximize the safety and minimize the cost. With regard to mechanical bolting, two important parameters need more advanced improvements and study, namely, optimum design of the shape and type of expansion shell and optimum bolt tension for a specific bolt pattern. For the fully grouted resin bolt, the most critical requirement is to develop a fast-setting, low-cost, intoxic, inflammable grouting material that can be used in the high speed mining cycle. It should be noted that geological conditions such as the strata type, rock properties,in situ stress, and planes of weakness play an important role in the successful application of any roof bolting system. These factors should be specified as accurately and quantitatively as possible in the design of any roof bolting system. Finally, proper and careful installation and continuous monitoring are imperative for the success of any roof bolting system.  相似文献   

碳同位素与早元古代地层对比   总被引：2，自引：0，他引：2  

钟华  马永生 《地层学杂志》1995,19(1):30-35

本文首次较详细地研究了早元古代碳酸盐地层的碳同位素组成，样品采自华北早元古代标准地层单元──山西五台地区滹沱群，结果表明碳同位素组成随地质时代有明显的变化，并与地层层位有很好的对应关系。作者认为，碳同位素对于早元古代碳酸盐地层的对比是很有用的。  相似文献   

松辽分水岭东段白土山组成因与时代   总被引：3，自引：1，他引：3  

王庆  杨景春 《地层学杂志》1995,19(4):287-290

综合考虑松辽分水岭东段地区白土山组的地层分布、沉积特征、地貌部位及第四纪以来松辽分水岭的演化过程、松辽水系的变迁，认为其为河流冲积物，形成时代为早更新世早期。  相似文献   

The stability of underground workings in the soft rocks of the Coal Measures   总被引：2，自引：1，他引：2  

A. H. Wilson 《Geotechnical and Geological Engineering》1983,1(2):91-187

Summary The characteristics of soft rocks typical of the British Coal Measures are defined and a series of working hypotheses are developed to provide improved design methods for underground roadway and face supports and pillars in coal mines. Proposed design equations are tested against case history data.  相似文献   

青藏高原渐新世晚期隆升的地质证据   总被引：26，自引：1，他引：26       下载免费PDF全文

吴珍汉吴中海  胡道功叶培盛 周春景 《地质学报》2007,81(5):577-587

国内外学者普遍认为,地壳缩短增厚是青藏高原隆升的主要原因,青藏高原隆升对环境变迁和东亚季风具有重要影响,但对青藏高原隆升时代存在不同认识。通过统计分析青藏高原中段新生代不同时期的地层倾角,表明区域褶皱变形主要发生于古近纪,中新世湖相沉积地层产状平缓,挤压构造变形微弱,说明地壳缩短增厚主要发生于中新世前。湖相沉积地层的孢粉分析结果表明,青藏地区热带亚热带阔叶林植被自始新世中期开始逐步减少,至中新世早期濒临消亡;暗针叶林植被自渐新世早中期开始逐步增加,至中新世早中期达到繁盛程度甚至居主导地位。根据这些地质证据,结合全球气候变化、古气温及年代学资料,综合推断青藏高原渐新世晚期隆升高度达到海拔4000m左右。  相似文献   

断陷湖盆碳酸盐与陆源碎屑混合沉积——以东营凹陷金家地区古近系沙河街组第四段上亚段为例   总被引：3，自引：0，他引：3       下载免费PDF全文

张金亮  司学强 《地质论评》2007,53(4):448-453,I0001

混合沉积是一种特殊的沉积类型,研究程度较低。金家地区处于东营凹陷的斜坡带,该区古近系沙河街组第四段上亚段发育了碳酸盐与陆源碎屑的混合沉积,研究认为该混合沉积为古湖泊内的混合沉积,可划分为混积砂滩亚相、混积砂坝亚相及半深湖混积亚相,混合沉积物既包括同层混合沉积物（灰质砂岩、砂质灰岩、泥质灰岩等）,又包括互层混合沉积物（砂岩与颗粒灰岩互层沉积等）,研究区的混合沉积受当时构造运动、碎屑物质供给量、湖平面的变化等诸多因素控制。  相似文献   

黑龙江鸡东盆地中中新世湖盆演变和植被变化研究     

舒军武  王伟铭  尹德顺  王金山 《地层学杂志》2007,31(3):247-254

黑龙江鸡东盆地是受古、新近纪敦密断裂带作用而形成的断陷含煤盆地。依据该盆地91-205钻孔永庆组的岩性变化特点和盆地构造演化阶段,识别和阐述了中中新世湖盆发育的3个阶段,即早期湖泊形成发展阶段、中期湖泊扩张最大阶段和晚期湖泊收缩衰退阶段,并揭示湖泊阶段性发展的旋回性特征。根据孢粉资料,恢复湖盆各个不同发育阶段的古植被面貌,重建当时的古气候。结果表明植被经历了北亚热带含常绿阔叶成分的落叶阔叶林、暖温带—北亚热带落叶阔叶林以及含亚高山针叶树种的暖温带—北亚热带落叶阔叶林阶段,鸡东盆地中中新世湖泊的演变和植被更替存在着潜在的关联。  相似文献   

Morphology and geological setting of Iseo Lake (Lombardy) through multibeam bathymetry and high-resolution seismic profiles     

Alfredo Bini  Daniele Corbari  Paolo Falletti  Mauro Fassina  Cesare R. Perotti  Andrea Piccin 《Swiss Journal of Geoscience》2007,100(1):23-40

  相似文献   

Dominant factors in controlling marine gas pools in South China     

Xu Sihuang  W. Lynn Watney 《Frontiers of Earth Science》2007,1(4):491-497

In marine strata from Sinian to Middle Triassic in South China, there develop four sets of regional and six sets of local source rocks, and ten sets of reservoir rocks. The occurrence of four main formation periods in association with five main reconstruction periods, results in a secondary origin for the most marine gas pools in South China. To improve the understanding of marine gas pools in South China with severely deformed geological background, the dominant control factors are discussed in this paper. The fluid sources, including the gas cracked from crude oil, the gas dissolved in water, the gas of inorganic origin, hydrocarbons generated during the second phase, and the mixed pool fluid source, were the most significant control factors of the types and the development stage of pools. The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale. Owing to the multiple periods of the pool formation and the reconstruction, the distribution of marine gas pools was complex both in space and in time, and the gas in the pools is heterogeneous. Pool elements, such as preservation conditions, traps and migration paths, and reservoir rocks and facies, also served as important control factors to marine gas pools in South China. Especially, the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale. According to several dominant control factors of a pool, the pool-controlling model can be constructed. As an example, the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up.  相似文献