中文摘要：

剪切波速和相对密度是评价无黏性土力学性能的重要参数指标。以砾性土的剪切波速测试技术为出发点，通过在特制的钢制承模筒上整合弯曲元的剪切波速测试技术，利用竖向振动台的驱动以改变筒内试样的相对密度，自主研发一套无黏性土剪切波速与相对密度联合测试系统，并对弯曲元剪切波速测试中的初至时间进行修正。该系统用于测试最大粒径小于50mm的无黏性土的剪切波速，建立无黏性土剪切波速与相对密度的哭系。针对标准砂试样、花岗岩圆砾试样、两者按含砾量60％配制的砾性土试样及根据汶川地震中液化砾性土平均级配配制的砾性土试样进行了剪切波速与相对密度联合测试，并与GDS大三轴剪切波速系统的测试结果进行对比。试验结果显示，所研发的系统与GDS系统对土样的测试结果相似，但适用范围更广，测试更简便；相同相对密度下，砾性土的剪切波速比砂土大；试样的剪切波速随相对密度的增加而呈现幂函数形式增长。

英文摘要：

Shear-wave velocity and relative density are important parameters to assess the properties of cohesionless soil. To measure the shear wave velocity of gravelly soil, a combined test system of shear-wave velocity and relative density was developed. The system was established on a specific steel bearing cylinder combining bending-element technique, and then applied on soil samples with different relative densities prepared by a vertically vibrating table. The first-arrival time of shear-wave in bending-element technique is corrected. The system is designed to test shear-wave velocity of gravel with maximum particle diameter less than 50 mm, and then to build relationships of shear-wave velocity with respect to relative density of cohessionless soil. Four types of samples, i.e., standard sand samples, granite samples, 60% gravel content samples constituting of standard sand and granite, and samples prepared according to the mean grading of gravelly soil that liquefied in Wenchuan earthquake, are tested and the results indicate that shear-wave velocity of gravelly soil is large than sand under same relative density. Shear-wave velocity of gravelly soil increases exponentially with respect to increasing relative density. Comparing to GDS apparatus, the testing shear-wave velocity of gravelly soil are similar yet the design system is more applicable and more convenient.