摘要
超声波波速测试作为一种无损检测已经广泛应用到岩土工程行业,该测试方法也是获得岩土体物理力学参数的有效方法.目前鲜有关于冻土的声波测试的技术和方法的报导,已有的冻土声波测试都是在垂直方向上忽略换能器的质量并在常温下快速测试声波通过时间,难以满足测试精度.鉴此,在购置常温声波测试主机的基础上,充分考虑冻土对温度敏感的特性、换能器在水平方向的测试以及土样与换能器之间的耦合程度,设计了一种适用于多种类型的冻土超声波换能器支架和恒温箱的测试系统,恒温箱意在提供适合不同温度下土体的测试环境(-30℃^+30℃),换能器支架可供低温、提供多种尺寸冻土试样的横波和纵波的测试平台.为避免垂直测试中换能器和土样自身对测试的影响,除了支架提供水平测试平台外,在调节换能器与土样接触距离的螺杆顶端放置应变片测试冻土样与换能器之间的接触程度以提高冻土声波波速的测试精度.利用该测试系统对不同负温下冻土样品进行测试,数据结果证明了该测试系统的实用性和良好的测试精度.
The ultrasonic detecting technique is highly efficient,handy and non-destructive,and reflects the physical properties of the tested object,which is widely used in geotechnical engineering testing. A little work has been done particularly on the techniques and methods of obtaining the ultrasonic velocity of frozen soil,and the current testing work is unable to meet the testing accuracy. So based on the mainframe of ultrasonic detecting,its operating temperature is- 5 ℃- ＋ 40 ℃,a test system for measuring ultrasonic wave velocity of frozen soil has been designed and developed sufficiently considering the frozen soil properties that it is sensitive to the temperature,the mass of energy transduce to the test object and the coupling between the testing object and the energy transduces. The system which can used to test the ultrasonic wave of the frozen soil with various sizes includes a constant temperature oven and the support for the energy transduces. The constant temperature oven offer the measurement environment with the temperature range from- 30 ℃ to ＋ 30 ℃,and the support for the energy transduces can be put into the oven during testing. To avoid the influence of the energy transduce mass on the test in vertical measuring,the support offers the horizontal testing platform,and a strain gage have been placed to monitor the coupling extent between the energy transduces and the testing objects to improve the testing accuracy. The testing results of the frozen soil with various temperatures using the system indicate the feasibility of the test system.
出处
《冰川冻土》
CSCD
北大核心
2016年第4期937-942,共6页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(41371090
41672310)
甘肃省科技重大专项计划项目(143GKDA007)
冻土工程国家重点实验室自主课题(SKLFSE-ZT-08)资助
关键词
冻土
超声波
换能器
温度
frozen soil
ultrasonic wave
energy transduce
temperature
