Evaluation of freezing state of sandstone using ultrasonic time-frequency characteristics
作者机构：University of Science and Technology BeijingBeijing100083China Permafrost LaboratoryDepartment of GeographyUniversity of SussexBrightonBN19QJUK Beijing Key Laboratory of Urban Underground Space EngineeringUniversity of Science and Technology BeijingBeijing100083China Department of Earth SciencesIndian Institute of Technology KanpurKanpurIndia North China University of TechnologyBeijing100041China
出 版 物：《Journal of Rock Mechanics and Geotechnical Engineering》 (岩石力学与岩土工程学报（英文版）)
年 卷 期：2023年第15卷第3期
页 面：584-599页
核心收录：
学科分类：08[工学] 080104[工学-工程力学] 0815[工学-水利工程] 0801[工学-力学（可授工学、理学学位）]
基 金：supported by the National Natural Science Foundation of China(Grant Nos.51804157,51774183,and 11702094) the University of Sussex,UK.Both are gratefully acknowledged
主 题：Frozen sandstone Uniform freezing Upward freezing Ultrasonic testing Freezing state
摘 要：Common problems in engineering projects that involve artificial ground freezing of soil or rock include inadequate thickness,strength and continuity of artificial frozen *** is difficult to evaluate the freezing state using only a few thermometer holes at fixed positions or with other existing *** we report a novel experimental design that investigates changes in ultrasonic properties(received waveform,wave velocity V_(p),wave amplitude,frequency spectrum,centroid frequency f_(c),kurtosis of the frequency spectrum KFS,and quality factor Q)measured during upward freezing,compared with those during uniform freezing,in order to determine the freezing state in 150 mm cubic blocks of Ardingly *** content,porosity and density were estimated during upward freezing to ascertain water migration and changes of porosity and density at different *** period of receiving the wave increased substantially and coda waves changed from loose to compact during both upward and uniform *** trend of increasing V_(p) can be divided into three stages during uniform *** upward freezing,V_(p) increased more or less *** frequency spectrum could be used as a convenient and rapid method to identify different freezing states of sandstone(unfrozen,upward frozen,and uniformly frozen).The continuous changes in reflection coefficient r_(φ),refraction coefficient t_(φ) and acoustic impedance field are the major reason for larger reflection and refraction during upward freezing compared with uniform *** velocity V_(p),wave amplitude A_(h),centroid frequency f_(c) and quality factor Q were adopted as ultrasonic parameters to evaluate quantitatively the temperature T of uniformly frozen sandstone,and their application within a radar chart is *** of V_(p) provides a convenient method to evaluate the freezing state and calculate the cryofront height and frozen section thickness of upward frozen sandstone,with
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