探地雷达在地铁盾构施工滞后沉降监测中的应用研究

Application of ground penetrating radar in the subsidence monitoring caused by the subway shield construction disturbance

在成都地铁2号线盾构施工过程中,由于成都地层特有的砂卵石层地质结构,产生地表滞后沉降问题.论文首先对此问题,建立了以空隙率为表征的地下介质扰动随时间发展的四个阶段的数值模型,应用有限差分数值模拟方法论研究和分析了源于滞后沉降的地下扰动不同发展时期的探地雷达反射波特征.然后结合成都地铁2号线盾构施工滞后沉降监测的对应的四个阶段探地雷达数据,分析了实际的滞后沉降地下扰动不同发展时期的雷达特征和灌浆治理效果的评价.论文通过数值模拟与实际雷达资料的对比研究结果,可为类似的城市地铁地表滞后沉降的探测和检测方法提供理论和技术的支持.

During the Chengdu Metro Line 2 shield construction,delayed settlements often arises due to construction disturbance to the special underground sand and gravel strata structure. At first,this paper conducts a numerical simulation using four models with various void ratio to study the GPR reflected wave images in the different periods of development of the underground disturbances caused by the shield construction. Then,the paper analyze the real radar image characteristics of delayed settlement measured from the four phases in the subsidence monitoring of Chengdu Metro Line 2delayed settlement and grouting evaluation. The research results can provide a theoretical and method support to the similar problems during City metro construction.