Hydrogeological and Engineering Geological Characteristics of Mangbang Formation Soft Rocks in Mangshi Basin,Western Yunnan Province：A Case Study of the Mangjiu Coal Mine

详细信息   

• 责任者：LV Yong (Institute of Karst Geology ; CAGS ; Guilin 541004 ; China) ; WANG Yu
• 刊名：Geological Bulletin of China
• 出版年：2012
• 卷期：31(2)
• 关键词：软弱岩石 ; weak rocks ; 煤岩 ; coal rocks ; 岩体力学 ; rock mechanics ; 云南 ; Yunnan Province
• 页码：p.382-388
• 图表：3 illus., 2 tables, 13 refs.
• 分类号：1702
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

摘要

The Mangshi basin is a continental sedimentary basins formed on the tectonic background of episode II of Himalaya Movement,with the primary filling substance being the river-lacustrine sedimentary system of Mangbang Formation.According to mining and drilling data,the engineering geological consolidation classification of Mangbang Formation is semi-soft rock,which can be divided into sandstone-sandy conglomerate soft rock group,siltstone weak rock group and carbonaceous mudstone-coal weak rock group.The coal seam is of low ash（15%-25%）,low sulfur（0.5%-2.5%）,semi-dark-half light brown type,and there exists a certain degree of self-ignition,The strength of the rock groups are in order of Psand-gravel Psilt Pmud-charcoal,the logging data and curves show that the coal seam has intermediate apparent resistivity,and the radioactive anomaly curve is obviously different from that of other rocks.The pumping test results show that the permeability coefficient k is in the range of 0.1-0.01,and the radius of the cone of depression is between 77 and 119 m.Although the distance from the Mangshi River to the drilling position is rather short,there is no obvious hydraulic connection,and the poor permeability rock possesses the major part.Mining exploration in the past 50 years has formed a number of mined-out areas and abandoned mined-out areas.Because these gobs are far away from the railway,the mined areas will not pose a threat to railway construction.