冻结井壁解冻过程中突水溃砂机理及防治技术

Mechanism and prevention technology of water inrush and sand inrush occurred in thawing process of mine freezing shaft wall

为了解决富水砂层冻结井壁解冻过程中突水溃砂灾害问题,通过理论分析、室内试验和现场测试,研究富水砂层冻结壁解冻过程中突水溃砂形成机理,低温环境下浆液的凝结特性和强度变化特征,注浆驱水、固砂技术和方法。研究结果表明:解冻过程中渗水通道为施工冷缝和混凝土收缩裂缝,涌水量随着解冻范围的扩大而增大,缝隙亦随之扩大,最终导致突水溃砂灾害;袖阀管注浆可有效充填井筒周围裂缝、驱水、固砂,添加水泥质量5%的工业盐可显著缩短水泥浆凝结时间,并且抗压、抗折强度增长明显。注浆后,井筒涌水量由400 m^3/h下降到70 m^3/h,达到封堵通道、减少物源、降低水头的目的。

In order to solve a water inrush and running sand problems occurred in the thawing process of the freezing shaft wall in the watery sand layer,with the theoretical analysis,indoor test and site test,a study was conducted on the formation mechanism of the water inrush and running sand occurred in the thawing process of the freezing shaft wall in the watery sand layer,the grout setting features under the low temperature environment and the technology and method of the grouting and water dispersed as well as the sand consolidation. The study results showed that during the thawing process,the water permeable channel would be the construction cold joints and the concrete shrinkage cracks. The water inflow would be increased with the thawing scope expanded,the cracks also would be expanded and finally a disaster of the water inrush and running sand would be caused. A grouting with a sleeve valve pipe could effectively backfill the cracks around the mine shaft liner,could disperse the underground water and could consolidate the sand. With the grout mixed with 5 % industrial salt,the mud slurry setting time would be obviously shortened and the compressive strength and bending strength both would obviously increased. After the grouting completed,the water inflow in the mine shaft was decreased from 400 m^3/h to 70 m^3/h and reached the targets to seal the channel,reduce the material sources and decrease the water head.