TBM施工隧道管片衬砌段回填注浆质量检测综合物探方法研究及应用

Research and Application of Comprehensive Geophysical Methods for Quality Testing of Backfill Grouting behind Lining Segment of TBM Construction Tunnel

针对目前无损检测方法应用于管片壁后回填注浆质量检测的局限性,综合地质雷达和地震映像法的优点对注浆质量进行可靠性检测。首先利用有限差分数值模拟方法分别对2种方法在管片后注浆质量的检测进行模拟,验证方法的理论检测效果。在该结果基础上,采用预测反褶积滤波技术对2种方法结果中的多次波进行有效滤除,以提高检测结果的准确性及可靠性。最后根据数值模拟实验结果,将数据滤波技术及最优探测参数在西藏某公路双护盾TBM施工隧道回填注浆质量检测中进行实际应用,并结合钻孔内窥结果对检测结果进行评价。结果表明:预测反褶积滤波技术能够有效滤除管片内钢筋模所产生的多次反射波,并能提高2种方法的分辨率;地质雷达法探测结果分辨率高,但受限于管片内钢筋模的影响,400MHz天线有效探测深度约为1m,地震映像法探测深度能达到5m左右,但分辨率低于地质雷达法,2种物探方法优劣互补;综合利用2种方法能够有效解决管片衬砌段回填注浆质量检测的难题,保障隧道建设安全。

For limitations of the present non-destructive detection methods in testing the quality of backfill grouting,by integrating the advantages of ground penetrating radar (GPR) method and seismic imaging method,reliability test of the grouting quality is carried out.The finite difference numerical simulation method is used to simulate the grouting quality testing of the two methods respectively,which verifies the theoretical detection effect of the methods.On the basis of the theoretical detection results,the predictive de-convolution filtering method is to effectively filter multiple waves in the results of two methods,which improves the accuracy and reliability of the detection results.Finally,according to the numerical simulation results,the comprehensive geophysical methods and data filtering technology is applied to the quality testing of backfill grouting behind lining segment of a double shield TBM construction tunnel in Tibet and are evaluated with the results of the borehole endoscopy.The testing results show that:(1) Predictive de-convolution filtering method can efficiently filter multiple waves caused by reinforcing bars,and increase resolutions of methods;(2) GPR method has a high resolution but limited to the dense steel mould contained in the lining segment,the effective detection depth is about 1 meter with 400 MHz antenna.While the depth of the seismic imaging method can reach about 5 meters,but the resolution is lower than the GPR method.These two geophysical methods are complementary to each other.(3)The comprehensive use of the two methods can effectively solve the quality testing of backfill grouting behind lining segment of TBM construction tunnel,and ensure safety of tunnel construction.