【作者】 唐海兵；

【导师】 凡友华； 耿光旭；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2008， 硕士

【摘要】 瑞雷面波勘探法是一种新型的工程地球物理勘探方法。由于该方法具有操作简便,探测速度快、对检测场地要求不高且能一次获得与深度相关的地层瑞雷面波速度参数的特点,因而在工程地质勘察和工程质量检测领域得到了广泛的应用。应用瞬态瑞雷面波法对公路工程的质量检测,具有非破损性、高代表性的优点,能很好的适应公路工程快速发展的需求。了解复杂公路路基中瑞利波的传播规律,对于分析研究复杂公路路基介质结构具有指导性作用。本文以公路路基中瑞利波的传播特性为基础,用有限元方法模拟实际公路路基中可能存在的缺陷情况,并对这些公路路基中的频散曲线进行了深入的分析与研究,本文研究的主要内容及成果如下:(1)基于公路路基各方面的参数资料,通过反复调整模型参数进行有限元计算和结果的对比分析,设计了符合实际公路完整路基情况的地层模型。(2)计算了公路路基第二层存在横向存在硬软分区的有限元模型,讨论了两种情况下横向软弱层波速、厚度、埋深和软硬分界线的位置的改变对频散曲线的影响,并进行了分析,发现公路路基中存在第二层存在硬软型横向分层与软硬型横向分层有明显的区别,并且频散曲线能反映出软区的波速、厚度以及软硬分界线的位置。(3)计算了公路路基第二层存在空洞的有限元模型,研究了空洞位于检测系统中不同水平位置时的频散曲线,指出了当空洞位于检波器下时,检测系统能最好地检测出空洞的特征。研究了空洞位于检波器下时长度、宽度、高度和埋深对公路路基频散曲线的影响,发现频散曲线次高频被拉出和频散曲线低频部分呈现出明显的“阶梯”形是公路路基存在空洞的重要特征,并且空洞的长度、宽度、高度与埋深的大小与“阶梯”形频散曲线有明显的对应关系。(4)通过研究了空洞的四个参数的雅克比矩阵Js并分析计算出它们的敏感性曲线,得出了空洞各个参数对频散曲线的敏感性大小。(5)本文将数值模拟计算结果与实测结果进行了比较,进一步验证了数值方法研究瑞雷波地基检测过程的可行性。本研究得出的结论,为工程技术人员用瑞利波法对公路路基进行检测提供了可靠的依据。更多还原

【Abstract】 The Rayleigh surface wave prospecting is a new method of the engineering geophysical exploration.It has been widely used in the domains of engineering geological exploration and engineering quality testing, since it is very easy and quick to operate and directly gets surface wave velocity relating to the depth of the strata.The method using transient Rayleigh surface wave has advantages of non-destructive test and good representation to meet the needs of the highly-developed highway engineering.The propagation disciplinarian of Rayleigh wave plays a guiding role in the analysis of complex roadbed structure. Based on Rayleigh wave propagation nature in roadbed, we have used the finite element method to simulate actual roadbed which is exist soft layer and cavity. Afterwards, dispersion curve of the roadbed have been analyzed and researched.The main content and conclusions are as follows:(1) The highway roadbed model which is in according with the actual situation has been designed, by consulting parameters’information of the roadbed and adjusting parameters of finite element.(2) The finite element model of the highway roadbed containing hard and soft district in the second layer has been calculated. The two situations have been discussed about different weak layer’s wave velocity, thickness, burying depth, the soft and hard boundary position changed, and the influences of these changes on frequency dispersion curve have been researched. We discover the result as follows: obvious differences are exist between the two situations’dispersion curve, and the dispersion curve can reflect the soft layer’s wave velocity, height and the position of the soft and hard boundary.(3) The roadbed model has been calculated in which the second layer containing cavity. The dispersion curves have been discussed when the horizontal location of cavity change, the result indicated that the examination system can get the best examination of empty characteristic when cavity is under the detector.When the cavity is under detector, the dispersion curve’s characteristics have been discussed when the cavity’s length, width, height and burying depth are changed.The result indicate that the high frequency of dispersion curve is pulled out and“steps and ladders”dispersion curve are the important characteristic when highway’s roadbed exists cavity, and“steps and ladders”dispersion curve can reflect the cavity’s length,width,height and burying depth.(4) The Jacobian matrixs Js of the cavity’s parameter have been studied, and the parameter’s sensitive curves have been analyzed.Finally, the value of parameter’s sensitivity to the frequency dispersion curve have been obtained.(5) This article also compares numerical simulation results with actual dispersion curve, and the feasibility of processing of Rayleigh wave stratum exploration by numerical simulation is verified.The conclusions of this paper provide reliable reference for engineer and technician to detect the roadbed using Rayleigh wave method.更多还原