Hetaoyu Coal Mine, Huaneng Qingyang Coal and Electricity Co., Ltd.
General Prospecting Institute of China National Administration of Coal Geology
Huaneng Coal Technology Research Co. , Ltd.

鄂尔多斯盆地南部诸多百万吨以上矿井，主采煤层为侏罗系延安组。由于煤层厚度大，煤层导水裂隙带高度导通了煤层上覆巨厚白垩系洛河组砂岩孔隙裂隙含水层，造成矿井涌水量巨大，严重威胁矿井生产。为了对厚层顶板水进行有效控制，该地区开展了一系列顶板注浆堵水工程试验，但由于常规水泥注浆仅对较大裂隙填充效果明显，因此开发了电化学注浆试验加强对砂岩中微细孔隙裂隙的封堵效果。选取宁正矿区洛河组砂岩作为研究对象，利用河沙及水泥根据洛河组岩石类型比例制作了砂岩模型材料，采用CaCl2和Na2SiO3浆液在砂岩模型材料中进行了2组电动化学注浆试验，浆液在阴极注入，各次注浆采用的电压均为40 V，浆液注入速度保持恒速，约10 mL/min，试验运行时间均超过了2 h。该试验验证了电动化学注浆在裂隙孔隙砂岩中的可行性。研究发现：相比胶体态的Na2SiO3浆液，溶液态的CaCl2浆液更适宜应用在孔隙砂岩电动化学注浆过程中；CaCl2溶液中的Ca2+离子在电场作用下迁移发生化学反应，在砂岩微细孔隙中形成了胶体；单位体积CaCl2溶液注浆需要的能耗为0.09 (kW·h)/L；金属电极在注浆过程中损耗严重，且会对含水层造成Fe污染，未来需针对如何选择环境友好且损耗较小的电极开展研究。

In the southern part of Ordos Basin, the main coal seam is Jurassic Yan 'an Formation. Due to the large thickness of coal seam the water-conducting fracture zone of the coal seam leads to the pore-fissure aquifer of the Cretaceous Luohe Formation sandstone overlying the coal seam, resulting in a huge amount of water inflow in the mine, which seriously threatens the mine production. In order to effectively control roof water in thick sandstone layer, a series of roof grouting and water plugging engineering tests have been carried out in this area. However, since conventional cement grouting can only fill large cracks, electrochemical grouting tests have been developed to strengthen the sealing effect of micro-pore cracks in sandstone. Luohe Formation sandstone in Ningzheng Mining area is selected as the research object, and sandstone model materials are made by using river sand and cement according to the proportion of rock types in Luohe Formation. Two sets of electrochemical grouting tests are carried out in the sandstone model materials with calcium chloride and sodium silicate grout. The grout is injected at the cathode, and the voltage used for each grouting is 40 V, and the grout injection rate is maintained at a constant speed 10 mL/min, the test running time exceeded 2 h.The feasibility of electro-chemical grouting in fractured pore sandstone is verified. It is found that calcium chloride grout in solution is more suitable for electrochemical grouting of porous sandstone than collidal sodium silicate grout. The calcium ions in the solution of calcium chloride migrate under the action of electric field and have chemical reactions, forming colloid in the micropores of sandstone. Energy consumption per unit grouting volume of calcium chloride solution needed for 0.09 (kW·h)/L. Metal electrode loss is serious in the grouting process, and will cause Fe pollution to aquifer. In the future, it is necessary to carry out research on how to select environmentally friendly electrodes with low loss.

华能集团总部科技项目资助（HNKJ20-H49）

杨小全，李　媛，郑洁铭，等. 孔隙砂岩电动化学注浆试验研究[J]. 煤炭科学技术，2023，51（S1）：328−333.

YANG Xiaoquan，LI Yuan，ZHENG Jieming，et al. Experimental study on electrochemical grouting of porous sandstone[J]. Coal Science and Technology，2023，51（S1）：328−333.