露天煤矿截水帷幕效果检验方法及截水效果分析

Inspection method and analysis of the effect of water cutoff curtain in open-pit coal mine

  • 摘要: 某露天煤矿为减少矿坑疏排水量,通过施工截水帷幕切断矿坑北侧河流补给通道。根据现场施工条件,采用低强度抗渗混凝土地下连续墙、HDPE防渗膜、超高压角域变速射流注浆、咬合桩4种工艺构建截水帷幕。为检验施工过程中露天煤矿截水帷幕的效果,针对低强度抗渗混凝土地下连续墙、HDPE防渗膜、超高压角域变速射流注浆等3种截水帷幕工艺,进行了4次围井试验。试验结果表明,在露天煤矿深厚砂卵石层动水、低温条件下,低强度抗渗混凝土地下连续墙、HDPE防渗膜、超高压角域变速射流注浆帷幕均具有良好的截水效果,渗透系数分别达到8.34×10-7、6.28×10-7、7.85×10-7 cm/s,与原材料室内实验得出的渗透系数基本吻合。在4种帷幕工艺的共同作用下,露天煤矿矿坑疏排水量显著减少,围井试验在截水帷幕施工过程中具有良好的效果检验作用。

     

    Abstract: In order to reduce the water drainage of the studied open-pit mine, a curtain wall was constructed to cut off the river supply on the north side. According to the site construction conditions, four technologies were applied to construct the water cutoff curtain, such as the low-strength impermeable concrete underground continuous wall, HDPE impermeable film, ultra-high pressure angular variable speed jet grouting, and occluding pile. To test the effect of water cutoff curtain in the open-pit coal mine during construction, four surrounding well tests were carried out for three kinds of water cutoff curtain technologies, including low-strength impermeable concrete underground continuous wall, HDPE impermeable film and ultra-high pressure angular variable jet grouting. The test results show that the three technologies all had good water-blocking effects under the conditions of dynamic water and low temperature in the deep sand and gravel layer of the open-pit coal mine. The permeability coefficients respectively were 8.34×10-7, 6.28×10-7 and 7.85×10-7 cm/s, which were basically consistent with the permeability coefficient obtained from the laboratory test of raw materials. Under the joint action of four curtain technologies, the water discharge was reduced obviously and the water intercepting effect was remarkable. The surrounding well test plays an inspecting role in the process of water cutoff curtain construction.

     

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