干密度和细粒含量对砂卵石及碎石抗剪强度的影响

Effects of dry density and percent fines on shearing strength of sandy cobble and broken stone

通过对河床砂卵石及爆破碎石的无黏性粗粒土直接剪切试验,对比分析了在不同试验状态下两种粗粒土的细粒含量和干密度分别对其抗剪强度参数的影响以及抗剪强度参数变化规律;试验结果表明,两种粗粒土的抗剪强度参数基本是随着干密度的增大而增大,摩擦角在细粒含量较小时稳定在某一特定值,随着细粒含量的增加而迅速减小;而当干密度增加到一定程度后不同试料在不同试验状态下,咬合力各自都将趋于某一稳定值。从两种试料的试验状态来看,非饱和固结抗剪强度参数相应地比饱和固结的大,河床砂卵石的抗剪强度参数比爆破碎石的大;对同一级配的河床砂卵石在不同相对密度下进行的直接剪切试验结果表明,其抗剪强度参数随着干密度的增大而增大,最终有趋于某一稳定值的趋势。

By means of direct shear test of the riverbed sandy cobble and broken stone, the sheafing strength parameters variation regular pattern are comparatively analyzed under different test conditions; and dry density or percent fines adjust sandy cobble and broken stone sheafing strength. The results of test indicated that the sheafing strength parameters are increased if dry density are improved for the two kinds of coarse grained soil; the fricton angles are stable amount in little percent fines, the sheafing strength parameters are reduced when percent fines are increased. The interlocking force are tended to stable amount when dry density are much improved in different test conditions for different coarse grained soil. The test results indicated that the sheafing strength parameters of the unsaturated consolidation direct shear test are larger than the saturated consolidation and riverbed sandy cobble shearing strength are larger than broken stone＇s too. The sheafing strength parameters are increased if dry density are improved and finally to steady tendency for the same riverbed sandy cobble.