黏土-砂混合物三轴压缩超声波特性研究
Investigation on Ultrasonic Wave Properties of Clay-Sand Mixture under Triaxial Compression Condition
刘桃根 1李玲 1王伟 2谢敬礼 3刘造保4
作者信息
- 1. 南昌工程学院土木与建筑工程学院,南昌 330099
- 2. 河海大学岩土力学与堤坝工程教育部重点实验室,南京 210098;河海大学岩土工程科学研究所,南京 210098
- 3. 核工业北京地质研究所,北京 100029
- 4. 东北大学深部金属矿山安全开采教育部重点实验室,沈阳 110819;东北大学深部工程与智能技术研究院,沈阳 110819
- 折叠
摘要
为研究核废料缓冲回填材料的超声波特征,本文利用岩石三轴压缩伺服仪和超声波测试系统,开展侧限压缩和常规三轴压缩2种应力路径和2种超固结比状态OCR=0.83和2.9的压实黏土-砂混合物的三轴压缩试验和超声波测试.结果表明:侧限压缩试验的纵、横波波速(Vp、Vs)曲线表现出与轴压-轴向应变曲线相似的3阶段特征,但Vp曲线具有滞后效应;常规三轴压缩试验的Vp增加,Vs降低,Vp和Vs变化与围压有关.动剪切模量和动泊松比(Gd和μd)的曲线分别与Vs和Vp的曲线相似,围压主要影响动剪切模量的大小;Vp和Vs与有效平均压力(p)有关,Vp和Vs与p的关系可用二次函数较好描述;横波信号的主频逐渐增大,主振幅先减小后增大,主频变得不易分辨,围压越大,横波信号衰减越强;Ⅰ和Ⅱ区随偏压加载而逐渐融合,横波分裂效应减弱.研究结果可为核废料缓冲回填材料的配比设计提供参考.
Abstract
In order to investigate the ultrasonic wave characteristic of buffer/backfilled material of the geological disposal for high level radioactive nuclear waste with highly buried depth,triaxial compression test including two different stress loading paths and OCRs,complying with ultrasonic test,are carried out by using the rock triaxial compression servo-controlled testing apparatus and the ultrasonic wave testing device.The stress loading paths performed correspond respectively to confining compression test and convention triaxial compression test.The OCR is set to be 0.83 and 2.9.The results show that the curves of velocity of compression wave and shear wave Vp and Vs can be also divided into three phases similar to that of stress-strain curve obtained from confined compression test.However,a hysteresis phenomenon can be observed from the curve of Vp.In the condition of deviatoric loading,the Vp increases with a gradually attenuation rate,the Vs seems to decreases linearly.The changes of both Vp and Vs are related to confining pressure.The evolutions of dynamic shear modulus and Poisson rate (Gd and μd) are similar to those of Vs and Vp,respectively.The Gd depends on confining pressure.A square polynomial correlation is proposed to describe the correlation between Vp and Vs and effective mean pressure p',which can reveal the influence of p on Vp and Vs.In terms of the analysis on spectrum and time-frequency spectrograph of the result obtained from the conventional triaxial compression test with effective confining pressure equal to 7.0 MPa,the main frequency of S-wave signal raises increasingly,but the main amplitude decrease firstly and then increases.It becomes ambiguity to identify the main frequency.The higher confining pressure,the stronger the attenuation of S-wave signal.A coalescence between the Ⅰ and Ⅱ time intervals can be observed,which refers to the abatement of the S-wave splitting effect.The findings obtained in this study can provide the basis for the design of buffer/backfilled material,and can also be used as a reference in other engineering projects.
关键词
压实黏土-砂混合物/三轴压缩/应力路径/超声波波速/小波变换/时-频谱Key words
compacted clay-sand mixture/triaxial compression/stress loading path/velocity of ultrasonic wave/wavelet transform/time-Frequency spectrograph引用本文复制引用
基金项目
江西省青年科学基金(20202BAB214028)
江西省教育厅科技项目(GJJ190979)
出版年
2024
NETL
NSTL
万方数据