工作面上覆松散含水层注浆改造及其效果检验

Grouting reconstruction of loose aquifer overlying work face and its effect test

为解放浅部“四含”煤柱资源,以五沟煤矿一采区1010-1工作面为试验对象,采用劈裂注浆法,连续与间歇注浆相结合的注浆工艺对“四含”及其底部基岩风化带进行注浆加固试验。结果表明:“四含”治理区岩性复杂,富水性弱,主要接受侧向区域径流补给,注浆改造工程将采用地面直孔结合定向斜孔逐排施工驱水固沙方案;混合浆液强度受制于粉煤灰掺比比例,且混合浆液强度、结石率均高于水泥净浆,粉煤灰掺量为20%时,结石率最高;浆液在“四含”中扩散极不均一,注浆过程需通过控制注浆量控制浆液扩散范围,注浆对地表影响体现在浆液扩散和压力传导,并以压力传导为主;注后取心孔样品真密度略有增大,含水率略有减小,抗压强度、抗拉强度、抗剪强度略有增大;基岩风氧化带注浆后岩层抗压强度随采样深度增加呈现先增大后减小再增大的趋势,其抗压强度增强约2~5倍。

In order to liberate the shallow quaternary loose aquifer coal pillar resources,taking the 1010-1 working face of the first mining area of Wugou Coal Mine as the test object,the grouting reinforcement test of quaternary loose aquifer and the weathering zone of the bedrock at the bottom was carried out by using the splitting grouting method and the grouting technology combining continuous and intermittent grouting.The results show that:the quaternary loose aquifer control area has complex lithology and weak water content,and mainly receives runoff recharge from the lateral area.The grouting reconstruction project adopts the water displacement and sand fixation scheme of the ground straight hole combined with the directional oblique hole row by row;the strength of the mixed slurry is subject to the ratio of fly ash,and the strength and stone rate of the mixed slurry are higher than those of the cement net slurry.When the fly ash content is 20%,the stone rate is the highest;the diffusion of grout in the quaternary loose aquifer is very uneven,the grouting process needs to control the grout diffusion range by controlling the grouting amount,the influence of grouting on the surface is reflected in the grout diffusion and pressure conduction,and the pressure conduction is the main one;after injection,the true density and water content of the core hole samples slightly increased,while the compressive strength,tensile strength and shear strength slightly increased;with the increase of sampling depth,the compressive strength of the rock layer in the wind-oxidized zone of bedrock increased first,then decreased and then increased,and the compressive strength increased about 2-5 times.