成型方法对级配碎石混合料抗剪性能的影响

研究振动和击实成型方法对级配碎石基层材料的应力应变特性和抗剪性能的影响,并分析强度差别产生的原因;试验中应用高精度静三轴仪对选定的级配碎石进行振动成型和击实成型的抗剪强度研究,揭示不同成型方法对抗剪强度的影响。试验表明,振动成型级配碎石的峰值应力、残余强度和初始模量较击实成型分别提高了22%、20%和90%,破坏应变有所降低,下降的幅度为10%;对强度参数来讲,内摩擦角φ提高2°,振动成型法的粘聚力C比击实法的提高了38%;振动成型试样的抗剪强度比击实的提高20%;振动成型试样的颗粒定向作用明显优于击实成型,使其抗剪强度高于击实成型试样。因此,在工程中要加强级配碎石的振动碾压,以提高级配碎石的抗剪强度潜能。

Influence of Compacting Methods on Grade Macadam Shear Characteristics

The shear strength and stress-strain relation of graded macadam in Vibrating Compaction(VC) and the Modified Proctor Compaction(MPC) were studied and compared,and the reasons of cause those difference were analyzed.Applying medium scale triaxial apparatus,the shear strength of grade macadam were carried out,the influence of different compaction methods on shear strength was proclaimed.Triaxial test results show that,peak stress,residue strength and initial modulus of VC sample increases 22%,20% and 90% respectively comparing with that of MPC sample,while failure strain decreases 10%;for the strength parameters,friction angle increases 2 degree,C value increases 38%,and shear strength increases 20% than that of Modified Proctor Compaction specimen.The granule directional action of Vibrating Compaction is strong than that of Modified Proctor Compaction.So,Vibrating Compaction should be applied widely in projects in order to enhance shear strength of grade macadam.