级配碎石混合料及其基层的抗剪性能

Shear characteristics of graded aggregate materials and graded aggregate base

为了研究级配碎石基层在路面结构中能否发生剪切破坏,对级配碎石基层材料抗剪强度及在路面结构中的剪应力进行了对比研究;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,采用有限元分析典型路面结构在标准荷载作用下剪应力的大小,明确级配碎石基层发生剪切破坏的可能性;三轴试验表明振动成型级配碎石过渡层的抗剪强度为0.17 MPa,击实成型的为0.14 MPa,振动成型试样比击实的抗剪强度提高20%;剪应力分析表明：水平荷载在级配碎石基层中产生的最大剪应力在0.04-0.05 MPa;级配碎石的抗剪强度是最大结构剪应力的3.5倍,级配碎石基层在高等级沥青路面结构中产生剪切破坏的可能性很小.

In order to study the breakage possibility of graded aggregate base in asphalt pavement structure, the shear strength of graded macadam materials and the shear stress of graded macadam base were researched. By applying a medium scale triaxial apparatus, the shear performances of grade macadam were carried out, the influence of different compaction methods on shear strength was proclaimed; through the structural shear strength analysis, the breakage possibility of grade aggregate base in asphalt pavement structure was made clear. Triaxial test results show that the shear strength of vibrating compaction specimen is 0. 17 MPa, that of modified proctor compaction specimen is 0. 14 MPa, the vibrating compaction specimen＇ s shear intensity increases by 20% than that of the modified proctor compaction specimen, the maximum structural shear strength of grade macadam base is from 0.04 MPa to 0. 05 MPa. The conclusions indicate that the grade macadam shear strength is 3.5 times of the maximum structural shear strength and the shear breakage possibility of the graded aggregate base in asphalt pavement structure is very small.