探地雷达属性分析技术及其在隧道地质预报中的应用研究

发布时间：2018-05-20 09:56

本文选题：岩溶隧道 + 地质预报　；参考：《广西大学》2017年硕士论文

【摘要】：目前西南岩溶地区高速公路处于快速发展阶段,许多隧道需要在复杂多变的地质条件下修建,然而隧道工程是一项隐蔽工程,在施工过程中会面临各种不同地质灾害。探地雷达具备采样快速、无损、操作简便、分辨率高等特点,作为一种有效的短距离地质预报手段,被广泛应用于隧道不良地质探测。本文在收集大量相关资料以及现场调研基础上,采用物理模型试验及数值分析等方法研究了典型岩溶不良地质探地雷达属性提取技术,并进行了典型岩溶不良地质探地雷达属性特征分析,研究成果有助于完善探地雷达岩溶隧道地质预报解译方法体系。本文主要研究内容如下:(1)在广泛搜集已开挖岩溶隧道地质资料、分析总结常见岩溶不良地质体形态特点及充填物质类型基础上设计室内模型试验,通过物理模型试验模拟了岩溶地区隧道施工经常遇到的典型不良地质体,分别获得不同深度、不同尺寸、不同形状以及不同填充物质的探地雷达数据。(2)引入基于属性分析的探地雷达信号解译技术,以物理模型试验数据为基础,分别分析了不同异常充填物时探地雷达探测剖面三瞬属性及反射波谱属性。研究结果表明:瞬时相位的分辨率最高,瞬时相位剖面图会在异常的位置表现为同相轴不连续,尤其当异常体为水时表现为相位反转180°;瞬时振幅特征随异常充填物和模型本身介质的相对介电常数的差异大小而变化,相对介电常数相差越大,表现越明显;瞬时频率特征表现不明显,可以辅助瞬时振幅特征进行目标识别;幅度谱能反映充填不同异常物时反射波的峰值特征及其与探地雷达天线主频值之间的差异;-3dB带宽的平均相位值有助于识别异常目标是否富水。(3)为更好地刻画探地雷达信号时频局部特征,引入基于广义S变换的探地雷达信号时频分析方法,该方法可以通过改变时间域及频率域调节因子k、p值获取不同时间域或频率域分辨率的时频变换结果,为岩溶不良地质探地雷达信号特征分析提供一种新思路。(4)以广西来马高速那黎二号隧道为工程依托,采用本文的方法对现场探测数据进行分析,取得了较好的应用效果,所提取的属性包括三瞬属性、频谱属性及时频属性。
[Abstract]:At present, the expressway in the karst area of southwest China is in a rapid development stage, and many tunnels need to be built under complicated and changeable geological conditions. However, the tunnel engineering is a hidden project and will face various geological disasters during the construction process. Ground penetrating radar (GPR) has the characteristics of fast sampling, nondestructive, simple operation and high resolution. As an effective short-range geological prediction method, GPR is widely used in tunnel poor geological exploration. On the basis of collecting a great deal of relevant data and field investigation, this paper studies the technology of extracting the attributes of typical karst geological prospecting radar by means of physical model test and numerical analysis. The analysis of the attribute characteristics of typical karst poor geological ground penetrating radar is carried out, and the research results are helpful to perfect the geological prediction and interpretation method system of the karst tunnel under the ground penetrating radar. The main contents of this paper are as follows: (1) on the basis of widely collecting geological data of excavated karst tunnels, analyzing and summarizing the morphological characteristics of common karst poor geological bodies and the types of filling materials, the model tests in the design room are designed. Through the physical model test, the typical bad geological bodies often encountered in tunnel construction in karst area are simulated, and different depths and sizes are obtained respectively. GPR data with different shapes and different fillers are introduced into GPR signal interpretation technology based on attribute analysis, which is based on physical model test data. The three instantaneous attributes and the reflectance spectrum attributes of the GPR detection profile with different abnormal fillings are analyzed respectively. The results show that the resolution of instantaneous phase is the highest, and the instantaneous phase profile is discontinuous in the anomalous position. Especially when the anomalous body is water, the phase inversion is 180 掳, the instantaneous amplitude characteristic changes with the difference of the relative dielectric constant between the abnormal filling and the medium of the model itself, the greater the difference of the relative dielectric constant is, the more obvious the performance is. The instantaneous frequency feature is not obvious and can assist the target recognition with instantaneous amplitude feature. The amplitude spectrum can reflect the peak characteristic of reflected wave and the difference between the peak value of reflected wave and the main frequency value of ground penetrating radar antenna. The average phase value of 3dB bandwidth can help to identify whether the abnormal target is rich in water. Time and frequency local features of radar signals, A time-frequency analysis method for ground penetrating radar signals based on generalized S-transform is introduced. The time-frequency transform results of different time-domain or frequency-domain resolutions can be obtained by changing the time domain and frequency domain adjustment factor kapp. This paper provides a new way of thinking for the analysis of the signal characteristics of karst poor geological ground penetrating radar. Based on the Nali No.2 Tunnel of Laima High-speed in Guangxi, the method in this paper is used to analyze the field detection data, and good application results have been obtained. The extracted attributes include three instantaneous attributes and frequency spectrum attributes.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U452.11

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