In order to solve the borehole sealing technical problems occurred in the gas pressure measuring process under the condition of the subhorizontal passed through strata drilling,based on the conventional borehole sealing technology and the cement self shrinkage effect,a two stage variable diameter pressurized borehole sealing technology was provided.With the two stage variable diameter of the borehole,a baffle welded at the variable diameter location and a distance to the borehole outlet reserved for the second sealing,in combination with the high pressure grouting technology applied to the borehole,a technique method to the borehole sealing and pressure measuring was realized.The technology was applied to the seam pressure measurement in No.1075 gas drainage gateway of Liulong Mine in Baise Group.The site test data were high efficiently and accurately measured and obtained.The study results showed that the two stage variable diameter pressurized sealing technology could effectively seal the top sectional notch of the sealing section of the subhorizontal pressure measuring borehole,could have a high leakproofness hole sealing and could provide the guarantee to accurately measure in-situ gas pressure of the seam.%为解决在近水平穿层钻孔条件下,测定瓦斯压力过程中出现的封孔技术难题,基于传统封孔技术以及水泥自缩效应,提出了钻孔两级变径带压封孔技术,通过钻孔两级变径、变径处焊接挡板及孔口预留距离二次封孔,结合高压注浆技术处理钻孔,实现封堵测压钻孔的工艺方法.应用该技术在百色集团六龙煤矿1075抽采巷进行了煤层瓦斯压力测定,高效、准确地测得了现场试验数据.研究结果表明:两级变径带压封孔技术能够有效封堵近水平测压钻孔封孔段上部的缺口,实现了高严密性封孔,为准确测定煤层原始瓦斯压力提供了保证.
展开▼
