含砾量对饱和砂砾土液化特性的影响

Effect of Gravel Content on Liquefaction Characteristics of Saturated Sandy Gravels

摘要:

利用GDS循环三轴仪进行一系列饱和砂砾土不排水动三轴液化试验,研究其在循环荷载作用下的液化特性,分析含砾量对饱和砂砾土动强度和动孔压的影响规律。研究表明:含砾量对砂砾土液化性能影响较大,随着含砾量的增加砂砾土抗液化强度呈单调增加趋势;随循环周次的增加孔隙水压力不断升高,增长速率与所施加的循环应力幅值有关,同一固结压力下,振次比相同时循环动应力幅值越大动孔压比越大;破坏振次对动孔压增长模式存在影响,破坏振次较小时砂砾土动孔压增长模式呈双曲线型发展,破坏振次较大时砂砾土的动孔压增长模式可用反正弦函数来表示,且含砾量越大循环荷载引起的孔隙水压力越高;含砾量对砂砾土液化特性的影响可从砂砾土的微细观结构特征得到阐释,并借助其粒间状态参量进行分析。

Abstract:

Using a GDS dynamic triaxial system,undrained dynamic triaxial tests on saturated sandy gravel were performed,the liquefaction characteristics of the saturated sandy gravel were analyzed,and the effects of gravel content on the dynamic liquefaction strength and dynamic pore pressure were analyzed.Results show that gravel content has a large influence on the liquefaction strength of saturated sandy gravel,monotonically increasing with increasing gravel content.The dynamic pore water pressure increases with the increase of cyclic times.When the consolidation ratio is the same,the dynamic pore water pressure ratio increases with increasing dynamic stress amplitudes under the same cycle ratio.The failure time of vibration affects the development pattern of pore water pressure significantly.The dynamic pore water pressure develops in the hyperbolic-type with lower failure time of vibration and can be expressed by the arcsine function for greater failure time of vibration.The dynamic pore water pressure increases with increasing gravel content.Effect of gravel content on the liquefaction characteristics of saturated sandy gravel can be explained from the microstructure features of the sandy gravel and can be analyzed through the inter-particle state parameters.