露天煤矿烧变岩黏土基注浆帷幕建造技术

Construction of clay-based grouting curtain in burnt rock of open-pit coal mine

为解决西湾露天煤矿东端帮烧变岩涌水问题,提出了在矿坑外侧烧变岩内建造一道截水帷幕的设想,并设计了截水帷幕的空间位置及结构参数;针对露天矿边帮变形、频繁爆破导致的帷幕墙抗渗性受影响问题,综合考虑技术、经济等因素,结合矿坑实际地质及采剥条件,提出了采用黏土基浆液建造露天矿柔性、抗震截水帷幕的新方法;针对烧变岩吃浆量大的问题,提出了黏土浆、黏土-水泥浆、黏土-水泥-水玻璃浆相互配合的黏土浆注浆新工艺,建造了一道长720m、深80m、有效厚度超过7m的截水帷幕墙;最后通过现场测量法、压水试验法、水位动态法检验了帷幕的质量与减水效果。结果表明帷幕墙透水率达到弱透水级别,帷幕墙外侧地下水位升幅明显,治理范围内涌水量由治理前的698m^(3)/h减少至71m^(3)/h,减水率达89%。

In order to solve the problem of water gushing from burnt rock at the east side of Xiwan Open-pit Coal Mine,an idea was proposed to construct a water cut-off curtain in burnt rock outside the mine,and the spatial location and structural parameters of the cut-off curtain were designed.As the impermeability of the curtain wall is impacted by the side wall deformation and frequent blasting,it’s proposed to construct flexible and earthquake-resistant water-cutting curtain for open-pit mine using clay-based grout,with comprehensive consideration of technology,economy,the actual geology and stripping conditions of the pit;in view of the large grout intake of burnt rock,a new clay-based grouting process was proposed using clay grout,clay-cement slurry,clay-cement-water glass slurry.A water-cutting curtain wall with a length of 720 m,a depth of 80 m,and an effective thickness exceeds 7 m was constructed.Finally,the quality of the curtain and the effect of water reduction were tested by field measurement,water pressure test,and dynamic water level test.The results showed that the curtain wall permeability of the curtain wall reached the level of weak water-permeable,the groundwater level outside the curtain wall rose significantly,and the water inflow within the treatment area was reduced by 89%,from 698 m^(3)/h to 71 m^(3)/h.