围压对粉质粘土动力学参数影响的共振柱试验研究

Resonant Column Experimental Study on Influence of Confining Pressure on Dynamic Parameters of Silty Clay

土的最大动剪切模量、剪应变幅和阻尼比是对土层进行动力反应分析的重要力学参数。利用英国GDS公司生产的RCA共振柱仪,研究围压对都江堰地区粉质粘土的上述动力学参数的影响。研究表明:相同围压条件下,最大动剪切模量、剪应变幅和阻尼比随重复次数基本不变,表明该试验过程具有可重复性;最大动剪切模量、剪应变幅和阻尼比均受围压影响较大,随着围压的增大,最大动剪切模量和阻尼比均逐渐增大,而剪应变幅随着围压的增大逐渐减小。据此,建立了都江堰地区粉质粘土动力学参数随围压变化的经验公式。本研究可为土层地震动力反应分析提供参考并积累基础资料。

The maximum dynamic shear modulus, shear strain amplitude and damping ratio of soil are important mechanical parameters for dynamic response analysis of soil layer. The influ- ence of confining pressure on the dynamic parameters of silty clay in Dujiangyan region was re- searched by RCA resonant column apparatus of British GDS Company. Studies show： Under the same confining pressure conditions, the maximum dynamic shear modulus, shear strain ampli- tude and damping ratio are essentially not change with repeat count, which show that the test process is reproducible. The maximum dynamic shear modulus, shear strain amplitude and damping ratio are greatly influenced by confining pressure. The maximum dynamic shear modu- lus and damping ratio are increasing, and the shear strain amplitude is decreasing with confining pressures increasing. The empirical formula of the dynamic parameters of silty clay in Dujiangyan vs. confining pressures is formed. The study can provide a reference to dynamic response analysis of soil seismic and accumulate basic data.