压实度和围压对路基压实黏质土抗剪强度的影响

Effect of confining pressure and degree of compaction on shear strength of compacted clayey soil

为了研究压实度和应力状态对路基承载能力的影响,以某工程压实黏质土为研究对象,通过三轴压缩试验研究了抗剪强度随压实度和围压的变化规律,利用水膜理论探讨了规律性变化的内在原因,并分别回归分析得到了抗剪强度与压实度及围压的函数关系式。结果表明:压实度和围压对路基压实黏质土抗剪强度的影响显著,其中抗剪强度随压实度的增加呈指数函数规律递增,随围压的增加线性递增,其影响程度均为密实状态比疏松状态明显,偏干状态比偏湿状态明显。适当提高施工压实标准、采取必要的侧限措施可显著提高路基承载能力。

In order to study the effect of stress state and degree of compaction on bearing capacity of subgrade,the engineering compacted clayey soil was taken as the subject investigated,regulation of shear strength changing with degree of compaction and confining pressure were analyzed through triaxial compression test,and the essential reason for the regulation were discussed by adopting the aqueous film theory,also function relationships between shear strength and degree of compaction and stress state were fitted based on the test data.Results show that effects of degree of compaction and confining pressure on shear strength properties of subgrade compacted clayey soil are all remarkably.The shear strength increases in accordance with an exponential function with the increase of the degree of compaction,and increases linearly with the increase of confining pressure.Effects of degree of compaction and confining pressure on shear strength are all more obvious when the compacted clayey soil in a more compacted or drier state.Improving the construction compaction standard properly and adopting the essential lateral confinement measure of the subgrade in service can improve the bearing capacity and stability of the highway subgrade.