盾构隧道壁后注浆的探地雷达探测模拟试验

针对现阶段软土盾构隧道壁后注浆过程中存在的问题及其可能引起后果的基础上,通过对隧道管片后的探地雷达探测目标的模拟试验研究,充分展示了隧道壁后充填“探测对象”时电磁波的传播规律。结合室内实体管片壁后注浆体和砂层的探地雷达无损探测模拟试验的研究成果,和基于FDTD法的GPR数据二维正演结果,对隧道壁后注浆体的分布形态进行了准确的识别。结果表明:隧道壁后注浆材料的龄期、分布形态以及组成材料配比对GPR探测的剖面图具有显著的影响。试验对探地雷达准确探测和解释盾构隧道盾尾壁后注浆效果具有十分重要的作用。

Simulation of GPR detecting of grouting materials behind shield tunnel segments

In recent years,there were some defects in the grouting behind the lining of shield tunnels which might cause some heavy aftermaths.When some were filled in the gap behind shield tunnel segments,the propagation rules of electromagnetic waves were summed up through a lot of simulation examinations of detecting of grouting materials behind shield tunnel segments with GPR(Ground Penetrating Radar).Combining simulation examination results with the two-dimensional model based on the finite difference time domain method(FDTD),the distribution of the grouting materials could be identified accurately.It was shown that the profile of GPR might be affected evidently by three factors: the curing period,different mixture ratios and distribution of gaps and grouting materials.Meanwhile,this simulation examination was important for GPR to interpret grouting effect behind shield tunnel segments.