成都地铁盾构滞后沉降的探地雷达波场数值模拟研究

发布时间：2018-04-29 18:31

本文选题：探地雷达 + 成都地铁　；参考：《西南交通大学》2015年硕士论文

【摘要】：随着城市地铁不断修建,由修建产生的众多地表塌陷问题也越来越严重。在监测地表沉降问题上,可以使用探地雷达作为探测手段,具有很好的效果。成都地铁地表具有特殊地质背景,地表下伏的是富水的砂卵石地层。成都地铁施工全部采用盾构施工法,该施工方法施工时,会引起地面机械振动、地下土与砂石流失等,很容易产生地表沉陷。从成都地铁1号线探地雷达探测资料来看,成都地铁地表所产生的地面沉陷并不是瞬时的即时沉陷,而是具有一定的“滞后性”。这种特殊的滞后沉降很难确定沉降时间,因此具备很大的不可预见性,给预防治理工作带来不便。时域有限差分法(Finite-Domain Finite-Time Method, FDTD)作为一种成熟的电磁数值计算方法,具有精度高,计算准确等特点。本论文从成都地铁特殊地质背景出发,建立了以空隙率、空隙大小和空隙流体介质为表征的三个数值模型来模拟成都地铁地下介质不密实带特征,运用FDTD法对其进行数值模拟,并通过MATLAB绘图显示、直达波去除和色标值统一等处理,分析对比各组模型探地雷达波场结果,得到了不同参数下的探地雷达波场响应特征。由于成都地铁地表沉降具有明显的滞后性,对其监测具有时长性。通过建立成都地铁2号线滞后沉降的监测方案,运用探地雷达进行滞后沉降探测。结合探地雷达数值模拟,分析对比四期雷达监测结果,得出成都地铁滞后沉降变化规律,为地铁滞后沉降防治提供理论基础和解决方案。
[Abstract]:With the continuous construction of urban subway, many problems of surface collapse caused by construction are becoming more and more serious. The ground penetrating radar can be used as a detection method to monitor the surface subsidence, and it has a good effect. The surface of Chengdu Metro has a special geological background. The shield construction method is used in the construction of Chengdu metro, which will cause ground mechanical vibration, soil and sand loss and so on, which can easily cause ground subsidence. From the ground penetrating radar data of Chengdu Metro Line 1, the ground subsidence caused by Chengdu Metro is not an instantaneous subsidence, but has a certain "lag property". This special delayed settlement is difficult to determine the settlement time, so it has great unpredictability and brings inconvenience to the prevention and treatment work. Finite-Domain Finite-Time method (FDTD) is a mature electromagnetic numerical method with high accuracy and accuracy. In this paper, based on the special geological background of Chengdu Metro, three numerical models, which are characterized by porosity, pore size and void fluid medium, are established to simulate the characteristics of undense zone of underground media in Chengdu Metro. The numerical simulation is carried out by using FDTD method. The results of direct wave removal and color calibration are analyzed and compared by MATLAB drawing. The response characteristics of GPR wave field under different parameters are obtained by analyzing and comparing the results of each group of model GPR wavefields. Because of the obvious lag of ground subsidence in Chengdu Metro, the monitoring time is long. Through the establishment of the monitoring scheme of delayed settlement of Chengdu Metro Line 2, the ground penetrating radar is used to detect the delayed settlement. Combined with the numerical simulation of ground penetrating radar, this paper analyzes and compares the results of four phases of radar monitoring, and obtains the variation law of the delay settlement of Chengdu metro, which provides the theoretical basis and solution for the prevention and treatment of the delay settlement of the subway.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U231.3;U456.3

【参考文献】