盾构隧道注浆质量地质雷达检测技术研究与应用

Research and Application of the Detection Technology for the Grouting Quality of the Shield Tunnel by the Ground Penetrating Radar

由于盾构隧道预制管片内部钢筋分布致密,致使管片背后注浆密实度地质雷达法检测的效果一直存在争议。为消除争议,拟通过对地质雷达技术原理的详细分析和不同钢筋间距对雷达波传播影响的数值模拟,阐释其是否具备探测盾构隧道管片壁后缺陷体的理论基础;依据盾构隧道实体情况,构建含有充水空洞、充气空洞、砂含水及泥含水缺陷体的数值模型和具有不同尺寸充水空洞的数值模型,以模拟不同缺陷体的波形特征;依托含有缺陷的1∶1盾构隧道物理模型,检验地质雷达对其缺陷体的探测效果;最后罗列了三处某在建盾构隧道的钻孔取芯实例。结果表明,从理论原理、数值模拟、物理模型及工程实例验证,均说明地质雷达法对于盾构隧道管片壁后缺陷体的探测效果良好,整体论断出地质雷达法是当前检测盾构隧道注浆质量的最佳方法。

Due to the dense distribution of steel bars inside the prefabricated segments of the shield tunnel,the effectiveness of the ground penetrating radar method for detecting the density of grouting behind the segments has always been controversial.To eliminate dispute,through analysing the principle of the ground penetrating radar technology and numerical simulation of the impact of different steel bar spacing on radar wave propagation,the theoretical basis for detecting defect bodies behind the segment of the shield tunnel is explained;based on the physical condition of the shield tunnel,the numerical model containing the cavity filled by water,the cavity filled by air,and the sand containing water and the mud containing water,as well as the numerical model with different sizes of cavities filled by water,are constructed to simulate the waveform characteristics of different defect bodies;based on the 1∶1 physical model with defect bodies of the shield tunnel,the detection effect of the ground penetrating radar on the defect bodies is tested;finally,three drilling and coring examples of a shield tunnel under construction are illustrated.The results indicate that the ground penetrating radar method has a good detection effect on the defect bodies behind the segment of the shield tunnel,as demonstrated by the theoretical principle,numerical simulations,physical model and engineering examples.The overall conclusion is that the ground penetrating radar method is currently the best method for detecting the quality of grouting in shield tunnels.