钻孔围岩封堵注浆材料与钻孔群封堵性能研究

Research on sealing grouting material of borehole surrounding rock and sealing performance of borehole group

为优化钻孔围岩封堵注浆材料,采用超细粉煤灰对硫铝酸盐水泥进行改进,分析了超细粉煤灰充填水泥颗粒的物理与化学作用机制,并对改进后的材料性能进行了试验分析,运用COMSOL数值模拟软件分析了材料对钻孔群封堵性能。结果表明:超细粉煤灰的晶核作用与水化产物相键合作用将会使复合材料表面产生更加致密的凝胶层,可以有效的对孔隙结构进行了充填。超细粉煤灰的比例对水泥的强度提升效果与含水量具有正向关系。当水灰比较大时,超细粉煤灰含量的增加将会大幅降低材料的渗透率,当水灰比较小时,超细粉煤灰对渗透率的影响效果不明显。在1.5 m孔间距的钻孔群条件下,应控制注浆压力为2 MPa,水灰比为5∶5,超细粉煤灰的比例为15%,黏度为0.01 Pa·s,可以达到良好的注浆封堵效果。

In order to optimize the sealing grouting material of the surrounding rock of the borehole,ultrafine fly ash was used to improve the sulfoaluminate cement,the physical and chemical mechanism of filling cement particles with ultrafine fly ash was analyzed,and the performance of the improved material was tested and analyzed.The COMSOL numerical simulation software was used to analyze the sealing performance of the material on the borehole group.The results show that the nucleation of ultrafine fly ash and the phase bonding of hydration products will produce a more dense gel layer on the surface of the composite material,which can effectively fill the pore structure.The proportion of ultrafine fly ash has a positive relationship between the strength improvement effect of cement and the water content.When the water-cement ratio is large,the increase of the content of ultrafine fly ash will greatly reduce the permeability of the material.When the water-cement ratio is small,the effect of ultrafine fly ash on the permeability is not obvious.Under the condition of the hole group with 1.5m hole spacing,the grouting pressure should be controlled to be 2 MPa,the water-cement ratio to be 5:5,the proportion of ultrafine fly ash to be 15%,and the viscosity to be 0.01 Pa·s,so as to achieve a good grouting sealing effect.