侏罗系煤田土-风化带-基岩型顶板导水裂隙带高度预计

Prediction of Height of Water-conducting Fissure Zone in Soil-Weathered Zone-Bedrock Roof of Jurassic Coalfield

为研究侏罗系煤田顶板基岩、风化带和土层对导水裂隙带高度的影响,利用钻孔探查了导水裂隙带在完整基岩中的发育高度和形态,模拟分析了厚土层、厚风化带和厚基岩3种类型顶板导水裂隙带发育特征和高度。根据相似地质条件矿井的导高实测资料,研究了土基比(土层和基岩的厚度比)与裂采比的关系。研究结果表明:侏罗系煤田导水裂隙带在完整基岩中发育的形态为拱形;风化带对导高的影响主要表现在能量被风化带内原有裂隙耗散,从而抑制了导水裂缝的继续向上发育,同时在完整基岩顶部会出现下行裂隙,随着基岩厚度比例减小导水裂隙带形态由拱形逐渐向马鞍形过度。当土基比小于0.4时,裂隙发育至土岩接触面附近,土层对导高发育有抑制作用;当土基比大于0.4,裂隙进入土层后裂采比明显增大,土层中发育上行裂隙,甚至切落至地表;根据实测资料拟合得到了土基比与裂采比的关系式。研究成果为侏罗系煤田导高合理预计提供了参考。

In order to study the mining fracture evolution characteristics of soil-weathered rock-bedrock roof in Jurassic coalfield,the development height and shape of the water-conducting fracture zone in the complete bedrock were investigated by drilling holes.The development characteristics and heights of three types of roof water-conducting fracture zones of thick soil layer,thick weathered zone and thick bedrock are simulated and analyzed.According to the measured data of the lead height of the mine with similar geological conditions,the relationship between soil-base ratio(thickness ratio of soil layer and bedrock)and crack-to-production ratio is studied.Research indicates:the actural form of the water flowing fractured zone developed in the complete bedrock is arched in the Jurassic coalfield.Energy is dissipated by the original fissures in the weathered rock,which inhibits the continued upward development of water flowing fractures,downward fissures will appear on top of the unweathered rock,as the proportion of bedrock thickness decreases,the shape of the water flowing fractured zone gradually change from arch to saddle.When soil-base ratio is less than 0.4,and the fissures developed near the soil-rock contact surface,soil layer inhibits fissures development,When soil-base ratio is greater than 0.4,crack-to-production increases significantly when the fissure enters the soil layer;ascending cracks develop in the soil layer,even cut to the ground surface.According to the collected data,the relationship between soil-base ratio and crack-to-production was obtained.The research results provide a reference for the reasonable estimation of the conduction height of the Jurassic coalfield.