探地雷达检测路面含水量和压实度的应用研究

【作者】 黎春林；

【导师】 王复明；

【作者基本信息】 郑州大学 ， 岩土工程， 2003， 硕士

【摘要】 路面的含水量、空隙率和压实度是公路建设中需要严格控制的指标，其如果达不到要求，将极大地影响到公路日后的使用性能。传统的检查方法是阶段性或完工后采用钻孔取芯对工程质量进行抽查检测评定，不仅效率低、代表性差、精度不高，而且对已建成的公路有损坏，已不能满足当前公路飞速发展的需要，为此发展一种快速、简便、高精度、高效率的公路质量无损检测技术是当务之急。 路用探地雷达是近几年发展起来的、应用于公路无损检测的一项新技术，它利用超宽带脉冲电磁波对路面结构层进行探测，当雷达发射天线发射的电磁波在路面结构层中传播时会在介电特性突变处产生反射和透射，反射回来的波经由接收天线接收并转化为数字信号储存起来，通过分析探地雷达回波信号来估计路面结构层的性质、状态和位置等特征。因为雷达技术具有无损、快速、简易的突出优点，在公路质量监控和路基路面检测、特别是高等级公路施工的质量监控以及养护等方面将有着宽广的应用前景。 目前探地雷达在公路上的应用还主要局限于路面结构层厚度的检测，对路基路面物理力学指标的无损检测被广大公路工作者寄予厚望，这一技术的应用还有很多的工作要做，为了使其早日应用于实际，实现探地雷达对路面含水量、空隙率和压实度的快速无损检测，本文具体做了以下的一些工作： (1) 鉴于介电常数对探地雷达检测的重要影响，对路面结构材料的介电特性进行深入分析，为路用探地雷达的实际应用测量提供理论依据。 (2) 鉴于探地雷达的发射频率对其检测的精度和深度都会产生重大影响，对介质的介电常数进行频域分析，分析介电常数随频率的变化趋势，并应用德拜(Debye)模型推导探地雷达用于路面质量检测的频率范围。 (3) 对探地雷达检测路面含水量、空隙率和压实度机理作理论分析，推导由雷达反射波计算含水量、压实度和空隙率等相关公式。 (4) 对路面面层、基层和地基的含水量以及沥青层空隙率对雷达反射波的影响进行分析，并对其特征波形进行模拟，为分析处理实际波形提供参考。 (5) 用探地雷达在实际路面采集数据对路面含水量、空隙率和压实度进行检测，通过对数据的分析处理探讨探地雷达检测路面质量的实用性、科学性和精确性。试验结果表明利用探地雷达检测路面的含水量和压实度是一个行之有效的方法。更多还原

【Abstract】 Water content, the voids and the density of the pavement are important indexes. These indexes have important influence on qualities of road. Traditional method to evaluate road, such as bore and sampling, will not meet the demands, because they have many disadvantages such as low efficiency, low-precision, bad representation and destruction. Therefore, a new, rapid, high-precision, effective and nondestructive technology is required to meet the engineering demand.Ground Penetrating Radar (GPR) is developed recently and is a nondestructive technology for road detection in a few years. GPR works near the surface of the road and transmits electromagnetic (EM) wave to the pavement layers. When the electromagnetic wave propagates in the pavement layers, it will be reflected at the interface of two different kinds of medium. As we know, different medium have different dielectric constant. The reflected wave will be received by the receive antenna and transferred to digital data. We can analyze the data that saved by the computer of GPR to deduce the medium’s property, situation, location and so on. Being a kind of nondestructive, untouched method, it has many advantages such as nondestructive, rapidness, simpleness and high precision, so it will have wide applications in the ways of examination, control and maintenance to road quality, especially for highway.But up to now, Ground Penetrating Radar (GPR) is mainly applied for road thickness detection and has still many jobs need to be completed. Moisture, the voids and the density of the pavement are expected for many operators in the road department. In order to promote the application of GPR to detect pavement quality as quickly as possible, in this paper some research works were zone. The mainly research results includes the following aspects:(1) Since the dielectric constants of pavement medium have important influence on radar detection results, dielectric properties of pavement layers materials are analyzed for the design of practical GPR system and field application.(2) Since central frequency of the antenna have important influence on depth and precision of detection results, frequency-dependence of dielectric constants of pavement medium are analyzed, and the range of central frequency are deduced using debye-model.(3) The principle of GPR to detect Moisture, the voids and the density of the pavement is analyzed and relevant formulae is educed.(4) Influence on reflected wave of the moisture of surface, base and subgrade andvoids of asphalt surface is analyzed and characteristic waves are simulated to offer reference to analyzing actual wave.(5) GPR tests were tried out in actual highway, then the practicability, rationality and accuracy are discussed in the bases of analyzing actual data. The results show that using GPR to survey pavement moisture and voids is an effective method.更多还原