西部地区钻井法凿井壁后充填模拟试验研究

Research on Simulation Backfill Test of Drilling Shaft Sinking Method in Western China

针对西部富水弱胶结地层中深立井钻井井筒壁后充填技术难题,开展了壁后充填模拟试验,对充填效果、充填层抗压强度和抗渗性能进行了分析。以可可盖煤矿中央回风立井钻井井筒为工程原型,基于相似理论原理构建了变态模拟试验系统,采用高性能微膨胀充填材料进行了钻井井筒壁后充填模拟试验。研究结果表明,高性能微膨胀充填材料整体置换护壁泥浆效果好,模拟试验各段置换率均达到97%以上,平均置换率为99.0%;充填层固结体3d抗压强度大于10MPa,28d抗压强度大于30MPa,其强度高、充填固井效果好;在流固耦合作用下,高性能微膨胀充填材料相较于传统水泥浆充填材料有更高的抗压强度和更好的抗渗性能,适宜作为深立井钻井井筒壁后充填材料。但模拟试验也发现,在模型最下部出现少量泥浆沉淀,该段置换效果相对较差。在实际工程充填前,调整泥浆参数、优化泥浆性能可以减少泥浆沉淀,提高工程充填效果。

Given the problem of technical difficulties of backfill in deep drilling shafts in water-rich and weakly consolidated stratum in western China,a simulation backfill test was carried out to analyze the backfill effect,compressive strength,and impermeability of the filling layer.Firstly,taking the central air return shaft of Kekegai Coal Mine as the engineering prototype,based on the principle of similarity theory,a variable shape simulation test system was constructed.Then,the high-performance micro-expansion backfill material was used to carry out the backfill simulation test of the drilling shaft.The results showed that the overall replacement effect of high-performance micro-expansion filling material was good,the replacement rate of all simulated test sections was more than 97%,and the average replacement rate was 99.0%.The 3-day compressive strength of the consolidation body of the filling layer was more than 10MPa,and the 28-day compressive strength was more than 30MPa,which indicated the strength was high and the filling cementing effect was good.Moreover,under the action of fluid-solid coupling,the high-performance micro-expansion filling material had higher compressive strength and better impermeability than the traditional cement slurry filling material,so it was suitable to be used as the backfill material for deep drilling shafts.However,the simulation results also showed that there was a small amount of mud precipitation in the bottom part of the model,and the replacement effect of this section was relatively poor.Therefore,before the actual engineering filling,mud parameters should be adjusted to optimize mud performance to reduce mud precipitation and improve the engineering filling effect.