碾压膨胀土波速变化规律及声波技术应用探讨

Discussion on Wave Velocity Change Rules of Compacted Expansive Soil and Application of Sonic Technology

针对百色地区膨胀土,利用TH204非金属超声波测试系统,对以最佳含水率和塑限含水率为控制含水率下的碾压膨胀土进行声波测试,得到了等幅度干湿循环作用后的纵波速度的变化规律.试验研究结果表明,随着循环次数的增加,不同控制含水率下碾压膨胀土试件的平均纵波速度呈非线性衰减,其0～1次循环,衰减程度最大.循环幅度对膨胀土的波速衰减有较大的影响,循环幅度越大,纵波速度衰减越大.结合声波技术在岩体材料中的应用,探讨了声波技术在路基膨胀土中的应用问题.

In relation to the expansive soil in Baise region, TH204 nonmetal ultrasonic testing system was used to conduct sonic test on the compacted expansive soil which takes the optimal and plastic limit moisture contents as the moisture content under control, then the change rules of P-wave velocity after the action of equal-amplitude dry-wet cycles was concluded. The study results show that, as the number of cycles increases, the compacted expansive soil specimen, under different values of moisture content under control, have the average P-wave velocity decayed nonlinearly, wherein the degree of decay was maximum in the 0-1st cycle ; the amplitude of cycle has so great impact on the wave velocity decaying that the larger the amplitude, the greater the decaying. Combining with application of sonic technolog~ in rock material, how this technique is applied to expansive soil of subgrade was discussed.