隧道穿越填充型溶洞超前帷幕注浆技术研究

Study on Advanced Curtain Grouting Technology for Tunnel Passing Through Filled Karst Cave

针对贵南高铁永兴一号隧道的填充型溶洞,采用多种超前地质探测技术探明溶洞的规模和填充状态;对溶洞导致的突泥涌水问题,选用洞渣换填方式进行处治。鉴于溶洞规模大且填充物丰富,选用超前帷幕注浆方案对隧道拱墙范围的溶洞充填物及围岩进行加固。结合地质探测结果确定注浆参数和范围,采用定量定压相结合的方法控制注浆过程。钻孔取样结果显示,当设计注浆填充率为15%~20%时,加固体各处的抗压强度均大于5.5 MPa,钻心采样率均高于85,达到较好的注浆效果,有效防治了隧道突泥涌水等问题,对帷幕注浆方案的选用和实施效果提出了参考与建议。

Based on the project of filled karst cave in Yongxing No.1 Tunnel of Guiyang-Nanning High-speed Railway,a variety of advanced geological detection technologies were used to verify^the scale and filling status of the karst cave.For the problems of mud outburst and water gushing caused by karst cave,the hole slag replacement method was adopted for the treatment.Due to the large scale of the karst cave and the rich filling material,the advanced curtain grouting method was used to strengthen the cave filling material and surrounding rock in the area of the tunnel arch wall.The grouting parameters and ranges were determined based on the geological survey results,and the grouting process was controlled by the combination of quantitative and constant pressure.The test results of the borehole sampling show that when the design grouting filling rate is 15%-20%,the compressive strengths of the solid of different positions are above 5.5 MPa,and the core sampling rate is higher than 85,achieving a better grouting performance and effectively preventing the potential disasters of mud outburst and water gushing.The suggestions and references are put forward for the selection and implementation of curtain grouting scheme.