滇西芒市盆地芒棒组软岩的水文、工程地质特征及其对工程的影响——以芒究煤矿为例
Hydrogeological and engineering geological characteristics of Mangbang Formation soft rocks in Mangshi basin, western Yunnan Province: a case study of the Mangjiu coal mine
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摘要: 滇西芒市盆地是在喜马拉雅构造运动第Ⅱ幕基础上形成的陆相沉积盆地，该盆地中的上新世芒棒组为河湖相沉积体系。根据矿区钻孔资料，芒棒组在工程地质岩组划分上属半固结软岩，可分为砂岩-砂砾岩软弱岩组、粉砂岩软弱岩组和炭质泥岩-煤层软弱岩组3类，各岩组强度依次为P砂-砾＜P粉砂＜P泥-炭。煤层为低—中灰分（15%~25%）、低硫—中硫（0.5%~2.5%）的半暗淡—半亮褐煤，有一定的自燃性。测井数据和曲线显示,煤层视电阻率中等，放射性异常曲线明显与其它围岩不同；抽水试验结果表明，渗透系数k在0.1~0.01m/d 之间 ，降落漏斗影响半径77~119m，煤矿虽然距离芒市河很近，但却无明显的水力联系，证实芒棒组整体透水性较差。矿山勘探、开采持续时间近50年，已形成了一些采空区和废弃采空区，由于距铁路优选线较远（1.5~2km），不会对大理-瑞丽铁路建设产生明显的影响。Abstract: 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
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Key words:
- western Yunnan Province /
- continental basin /
- coal rock /
- logging curve /
- weak rock group /
- depression funnel
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