土壤干密度和含水率对2种紫色土抗剪强度的影响

选择广泛分布于重庆丘陵山区的钙质紫色土和中性紫色土2种土壤,通过室内三轴剪切试验测定含水率和干密度交互作用对土壤抗剪强度指标的影响。结果表明:(1)在相同干密度情况下,2种土壤粘聚力(c)随着含水率增加呈现出先增加后减小的趋势,在相同土壤含水率水平下,土壤粘聚力(c)随干密度增大而增大;2种土壤内摩擦角(φ)在各干密度条件下均随着含水率增加呈明显减小的趋势。(2)含水率和干密度的交互作用对粘聚力(c)有显著影响,粘聚力(c)随着干密度的增大而增大,且每一个干密度都有一个含水率与之对应,并在此交互条件下c达到最大。钙质紫色土粘聚力(c)在干密度为1.7g/cm3,含水率为11%时达到极大值,此时粘聚力(c)为154.59kPa,中性紫色土粘聚力(c)在干密度为1.6g/cm3,含水率为8%时达到极大值,此时粘聚力(c)为126.38kPa。(3)含水率和干密度的交互作用对内摩擦角(φ)影响相对较小,同一干密度下,其φ值差异不大,随干密度的增大缓慢增大,相对而言,含水率对内摩擦角(φ)的影响更明显。钙质紫色土内摩擦角(φ)随含水率的增大呈曲线下降,中性紫色土内摩擦角(φ)随含水率增大有一个短暂的增大过程,而后随之迅速减小。

Effect of Soil Water Content and Dry Density on Soil Shearing Strength for Calcareous Purple Soil and Neutral Purple Soil

Based on the triaxial shearing test in laboratory,effect of soil water content and dry density on soil shearing strength was determined for calcareous purple soil and neutral purple soil.Experimental data indicated that the soil cohesive force firstly increased and then decreased with the increasing of soil water content under the same soil dry density,and it increased with the increasing of soil dry density under the same soil water content.The internal frictional angle of two types soil fleetly decreased with the increasing of soil water content.There was close relation between the interaction of soil water content and dry density and soil cohesive force,and the soil cohesive force reached to the maximum under the interaction of soil water content and dry density that each soil dry density matched the specifically soil water content.The maximum of soil cohesive force for calcareous purple soil was 154.59 kPa under soil dry density 1.7 g/cm3 and water content 11%,for neutral purple soil was 126.38 kPa when soil dry density was 1.6 g/cm3 and water content was 8%.The interaction of soil water content and dry density was small relatively on the internal frictional angle,and the internal frictional angle tardily increased with the increasing of soil dry density.The internal frictional angle of calcareous purple soil nonlinearly decreased with the increasing of soil water content and there was the transitory increasing and then fleetly decreasing for the internal frictional angle of neutral purple soil.