现场剪切波速测试误差及其对地震动影响研究

发布时间：2018-02-25 18:33

本文关键词： 剪切波速测试误差分布偏差量地震动　出处：《中国地震局工程力学研究所》2015年博士论文　论文类型：学位论文

【摘要】：剪切波速是岩土体介质一个重要参数,由于测试结果直观、操作简单易行,现场剪切波速实验已经成为工程中常用的实验之一。对任何一个可以重复测量科学数据,其误差水平、置信区间都是必须回答的问题,但迄今为止现场剪切波速测试误差专门研究基本为空白。这就导致工程和科研人员对现有剪切波速测试技术的精度争论很大,对其结果的可靠性心存疑虑,也无法制订相关标准并改进技术。同时,场地波速离散性对地震动的影响一直是一项重要的研究课题,但由于波速实测误差未知,以往的研究只能采用假定的波速离散程度研究其对地震动的影响。这就导致分析结果缺乏依据,也无法从波速对地震动影响的角度评价现有波速实验的精度和技术水平。本文紧密结合工程和科研工作需求,设计了剪切波速测试误差专项实验并获得了较为系统的实验结果;对测试误差的分布进行了统计建模并对其进行了评价;采用实测的剪切波速测试误差计算分析了其对地震动的影响,依据统计结果给出了不同概率水平的波速测试误差对地震动的影响程度评价。本文通过大量的现场工作以及计算分析,研究了现场剪切波速测试误差及其对地震动的影响,完成了以下工作:组织了国内55家具有代表性的单位,在中国大陆8个地区的20个不同类别的场地上,第一次完成了现场剪切波速测试误差专项实验,获取了600组实测数据。数据分析表明测试结果符合统计学理论,实验设计合理、结果可靠。通过实测数据,分析了测试环境对剪切波速测试误差的影响,指出其中影响较大的是实验场地的环境噪音。噪音较大的场地波速测试的离散性较大,而土性、地下水埋深等因素对波速测试误差基本没有影响。建立了现场剪切波速测试误差的分布模型并进行了统计检验,第一次给出了现场剪切波速测试误差的分布特征,得到了不同场地类别、不同测试深度的剪切波速测试误差水平基本相当的重要结论,给出了评价波速测试技术水平的初步建议。通过实测数据,研究了在不同地震波输入时,不同类别场地上的波速测试误差对地震动的影响;以PGA和SI为指标,提出了不同概率水平的剪切波速测试误差对地震动影响的评价结果。
[Abstract]:Shear wave velocity is an important parameter in rock and soil media. Because of the intuitionistic test results and simple operation, the field shear wave velocity experiment has become one of the commonly used experiments in engineering. The error level and confidence interval are all the questions that must be answered, but so far the research on the field shear wave velocity measurement error is basically blank. This has led to a great controversy between engineering and scientific researchers on the accuracy of the existing shear wave velocity measurement technology. There are doubts about the reliability of the results, and it is impossible to formulate relevant standards and improve the technology. At the same time, the influence of wave velocity dispersion on ground motion is always an important research topic, but the error of wave velocity measurement is unknown. Previous studies can only use the assumed dispersion of wave velocity to study the effect of wave velocity on ground motion, which leads to the lack of basis for the results of the analysis. It is also impossible to evaluate the accuracy and technical level of the existing wave velocity experiment from the point of view of the influence of wave velocity on ground motion. In this paper, a special experiment of measuring error of shear wave velocity is designed in combination with engineering and scientific research work, and more systematic experimental results are obtained. The distribution of measurement error is modeled and evaluated, and the influence of the error on ground motion is calculated and analyzed by using the measured shear wave velocity measurement error. According to the statistical results, the influence degree of wave velocity measurement error at different probability levels on ground motion is evaluated. Through a lot of field work and calculation and analysis, the field shear wave velocity measurement error and its influence on ground motion are studied. The following work has been accomplished: 55 representative units in China have been organized, and a special experiment on the measurement error of field shear wave velocity has been completed for the first time on 20 different sites in 8 regions of mainland China. 600 sets of measured data are obtained. The data analysis shows that the test results are in accordance with the statistical theory, the experimental design is reasonable and the results are reliable. Through the measured data, the influence of test environment on the error of shear wave velocity measurement is analyzed. It is pointed out that the environmental noise of the experimental site is the most important one, and the dispersion and the soil property of the measurement of the wave velocity of the experimental site are larger than those of the experimental site. The distribution model of in-situ shear wave velocity measurement error is established and the statistical test is carried out. The distribution characteristics of the field shear wave velocity measurement error are given for the first time. An important conclusion is obtained that the error level of shear wave velocity measurement is basically equal for different site types and different testing depths, and a preliminary suggestion for evaluating the technical level of wave velocity testing is given. Through the measured data, it is studied that when different seismic waves are input, The influence of wave velocity measurement error on ground motion in different types of sites is presented, and the evaluation results of shear velocity measurement error at different probability levels on ground motion are presented using PGA and SI as indicators.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU435

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