国省干线养护工程大粒径级配碎石基层承载性能研究

Research on the bearing capacity of large particle graded crushed stone base in National and Provincial mainline maintenance projects

通过现场承载力检测,研究了大粒径级配碎石基层承载性能。分析了重载交通量对大粒径级配碎石承载力形成机理及影响规律:承载力随重载交通作用次数分为明显增长阶段、增长缓慢阶段、无变化或降低阶段;研究了大粒径级配碎石承载力均质化提升机理:从全线整体弯沉情况分析,降低全线旧路弯沉离散程度,减缓旧路承载力的不均匀性。从局部变形进行研究,荷载作用区域,其顶面弯沉盆曲线斜率要小于旧路顶弯沉曲线斜率,加强路面变形协调性及对荷载传递扩散性,减缓应力集中现象;现场实测反算得到了大粒径级配碎石基层回弹模量约在700 MPa~850 MPa水平之间,较普通级配碎石模量回弹模量增长约在20%~320%,承载能力有较大幅度提升。

This article researched the bearing capacity of large particle size graded crushed stone base through on-site bearing capacity testing.Analyzed the mechanism and influence of heavy traffic volume on the bearing capacity of large particle graded crushed stones:the bearing capacity can be divided into three stages with the number of heavy traffic actions:a significant increase stage,a slow increase stage,and no change or decrease stage;researched the homogenization improving mechanism of the bearing capacity of large particle graded crushed stones:from the overall deflection situation analysis of the entire line,to reduce the deflection dispersion of the old road and slow down the unevenness of the bearing capacity of old road.From the perspective of local deformation,in the load application area,the curve slope of of top curved basin should be smaller than that of the old road top,in order to enhance the coordination of pavement deformation and the load transmission and diffusion,and alleviate the stress concentration phenomena;On site measurement and back calculation showed that the rebound modulus of large particle size graded crushed stone base is between 700 MPa and 850 MPa,which is about 20%to 320%higher than that of ordinary graded crushed stone,the bearing capacity has been greatly improved.