防渗注浆是工程实践中用来解决复杂地质条件下突泥涌水问题的一项重要手段，其注浆封堵效果很大程度上取决于目标含水层基本情况、导水通道发育特征、注浆材料及注浆工艺的选取。粉煤灰作为大宗工业固体废弃物，具有特殊的物理和化学性能，将粉煤灰进行资源化利用，不仅可以减少环境污染、还可以提高粉煤灰经济效益。为了掌握粉煤灰基防渗注浆材料的工程性能，采用正交试验方法对粉煤灰-硅酸盐水泥混合胶凝材料进行了基础性能测试。通过极差与方差分析方法研究了水固比、水泥粉煤灰固相比、激发剂及温度4个因素对浆液的流动度、密度、结石率、析水率、初凝时间及终凝时间6项指标的影响规律。试验结果表明：水固比对浆液6项性能指标均有较大影响；固相比主要影响浆液流动度及凝结时间；掺入适量外加剂可以加快浆液凝结速率；升高温度有利于缩短浆液凝结时间、增大结石率和减小析水率。采用综合平衡分析法得到浆液优选方案：水固比为0.8∶1.0、固相比为30∶70，激发剂掺量为2%，温度尽量控制在15 ℃以上。将该优选方案在国内某露天煤矿地下帷幕截水综合技术研究与示范工程进行了初步应用，结果表明：浆液固结后形成连续完整的帷幕，从根本上切断了矿区地下水渗流补给通道，降低了矿坑水输排工作压力，保障了煤矿运行安全，节约了工程成本。

Impermeable grouting is an important means to solve the problem of mud and water inrush under complex geological conditions in engineering practice. The sealing effect of grouting largely depends on the basic conditions of target aquifer, the development characteristics of water channel, the selection of grouting materials and grouting technology. As a bulk industrial solid waste, fly ash has special physical and chemical properties. The utilization of fly ash as a resource can not only reduce environmental pollution, but also improve the economic benefits of fly ash. In order to master the engineering properties of fly ash-based impervious grouting materials, the basic properties of fly ash-Portland cement mixed cementitious materials were tested by orthogonal experiment method. The influence law of water-solids ratio, cement-fly ash ratio, activator and temperature on fluidity, density, concretion rate, water precipitation rate, initial setting time and final setting time of fly ash based impermeable grouting materials is analyzed by means of range analysis and variance analysis. The results show that the water-solid ratio has great influence on the six performance indexes of the slurry. The solid ratio mainly affects the fluidity and setting time of slurry. The setting rate of slurry can be accelerated by adding activator appropriately. The increase of temperature is beneficial to shorten the setting time, increase the concretion rate and decrease the water extraction rate of slurry. The optimal solution of slurry has been put forward by comprehensive equilibrium analysis method：the water-solids ratio is 0.8∶1, the cement-fly ash ratio is 30∶70, the mixing amount of activator is 2%, and the temperature should be above 15 ℃ as far as possible. The optimal scheme has been preliminarily applied in the research and demonstration project of underground curtain water interception technology in an open pit coal mine in China. The results show that a continuous and complete curtain is formed after the slurry consolidation, which fundamentally cuts off the groundwater seepage supply channel in the mining area, reduces the pressure of water transport and discharge in the mine, ensures the safety of the coal mine operation, and saves the engineering cost.