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(V_(p)、V_(s))曲线表现出与轴压-轴向应变曲线相似的3阶段特征,但V_(p)曲线具有滞后效应;常规三轴压缩试验的V_(p)增加,V_(s)降低,V_(p)和V_(s)变化与围压有关。动剪切模量和动泊松比(G_(d)和μ_(d))的曲线分别与V_(s)和V_(p)的曲线相似,围压主要影响动剪切模量的大小;V_(p)和V_(s)与有效平均压力(p)有关,V_(p)和V_(s)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。
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 V_(p)and V_(s)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 V_(p).In the condition of deviatoric loading,the V_(p)increases with a gradually attenuation rate,the V_(s)seems to decreases linearly.The changes of both V_(p)and V_(s)are related to confining pressure.The evolutions of dynamic shear modulus and Poisson rate(G_(d) and μ_(d))are similar to those of V_(s)and V_(p),respectively.The G_(d) depends on confining pressure.A square polynomial correlation is proposed to describe the correlation between V_(p)and V_(s)and effective mean pressure p',which can reveal the influence of p on V_(p)and V_(s).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 Ⅰand 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.
作者
刘桃根
李玲
王伟
谢敬礼
刘造保
Liu Taogen;Li Ling;Wang Wei;Xie Jingli;Liu Zaobao(School of Civil and Architectural Engineering,Nanchang Institute of Technology,Nanchang 330099,P.R.China;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210098,P.R.China;Institute of Geotechnical Engineering,Hohai University,Nanjing 210098,P.R.China;Beijing Research Institute of Uranium Geology,Beijing 100029,P.R.China;Key Lab of Ministry of Education on Safe Mining of Deep Metal Mines,Northeastern University,Shenyang 110819,P.R.China;Institute of Deep Engineering and Intelligent Technology,Northeastern University,Shenyang 110819,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2024年第S01期119-127,共9页
Chinese Journal of Underground Space and Engineering
基金
江西省青年科学基金(20202BAB214028)
江西省教育厅科技项目(GJJ190979)。
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
compacted clay-sand mixture
triaxial compression
stress loading path
velocity of ultrasonic wave
wavelet transform
time-Frequency spectrograph
