压实条件及细粒含量对压实土动强度的影响研究

为了深入研究压实条件与细粒含量对土动强度的综合影响,对湖南省五种不同级配的土开展了循环荷载三轴试验,探讨了含水率、干密度、饱和度对不排水动强度的影响规律及机理,分析了不同细粒含量压实土所呈现的动强度特征差异,并引入以压实度和饱和度为自变量的方程来定量表述动强度。研究结果表明:在一定的压实能量下,达到最大干密度的土并不一定具有最大的不排水动强度,对于细粒含量较大的土,动强度由压实度和饱和度同时决定,而对于细粒含量较小的土,动强度基本只受压实度的影响;利用动强度预测方程可以在不掌握击实曲线的前提下预测压实土的不排水动强度,并可以在控制饱和度的前提下得出满足目标不排水动强度所需的压实度。

Influence of compaction conditions and fines content on the dynamic strength of compacted soil

To further study the compaction conditions and fines content coupling effect on soil dynamic strength characteristics,a series of cyclic loading tri-axial tests were carried out on five kinds of compacted soil of Hunan province with different gradations.The influence and corresponding mechanism of the moisture content,dry density and saturation on the undrained dynamic strength were discussed.The discrepancy of dynamic strength characteristics caused by fines content difference was analyzed.And a function with compaction degree and saturation degree as independent variables was introduced to quantitatively express the dynamic strength.The results show that under a certain compaction energy,soil with maximum dry density may not reach the maximum undrained dynamic strength.For the soil with high fines content,its dynamic strength is determined by both the compaction and saturation degree,while for the soil with low fines content,its dynamic strength is only affected by the compaction degree.The undrained dynamic strength of compacted soil can be estimated by the function without knowing compaction curves.Meanwhile,the compaction degree needed for achieving the target undrained dynamic strength can be calculated by controlling the saturation degree.