针对某300 m级特高土石坝防渗砾石土料,配制了不同P₅含量的试验料,对P₅含量对土料击实特性、强度特性、变形特性和渗透特性的影响开展了试验研究。确定了该工程防渗砾石土料的第一、第二含砾量特征值分别为37%和60%。最大干密度、最优含水率分别随着P₅含量的增加而逐渐增加、降低,但当P₅含量在60%~75%之间时,最大干密度出现持平,直至P₅含量增加到80%后才出现降低,最大干密度出现持平段的原因可能与颗粒破碎有关。随着P₅含量增加,土料的压缩模量、抗剪强度参数、变形参数、渗透系数逐渐增加,渗透特征坡降逐渐降低,土料渗透变形破坏模式发生改变。

In this study, soil samples with varying P₅ content were prepared for the impervious gravel soil of a 300 m ultra-high earth-rockfill dam. Tests were conducted to investigate the influence of P₅ content on the compaction, strength, deformation, and permeability characteristics of the soil samples. The characteristic values of the primary and secondary gravel content for the project were determined as 37% and 60%, respectively. With increasing P₅ content, the maximum dry density gradually increased while optimum moisture content decreased. When P₅ content ranged from 60% to 75%, the maximum dry density remained stable and did not decrease until the P₅ content reached 80%. This stable stage can be attributed to particle breakage. Additionally, as P₅ content increased, the compression modulus, shear strength parameters, deformation parameters, and permeability coefficient of the soil gradually increased, while the characteristic hydraulic gradient gradually reduced, and consequently changing the seepage failure mode of the soil.