客运专线基床底层砾石土填料物理力学性质试验研究

对取自武汉—广州客运专线路基基床底层的砾石土填料开展颗粒分析、相对密度、多种击实、大型剪切/压缩/渗透等粗粒土特种土工试验。得到以下结论:(1)粗细颗粒含量适当的无黏性砾石土填料,较易形成密实骨架结构,从而获得优良力学性能,并表现出较好的可压实性;(2)良好级配的砾石土填料,对应规范要求孔隙率的压实系数偏低,采用压实系数作为控制指标更为严格、可靠;(3)运用构建的"模量折减率法"和"卸载回弹率法"分析发现,压实系数0.90和0.95分别对应骨架疏松和密实土体结构状态,并在强度、变形和渗透性能等方面差异明显。

Experimental Research on Physical and Mechanical Properties of Gravelly Soil Filling the Base Course of the Subgrade Bed of Passenger Dedicated Line

Particle analysis,relative density tests,multi-type compaction tests,large-size shear tests,large-size compression tests and large-size permeability tests were made with the gravel filler taken out from the base course of the subgrade bed Wuhan-Guangzhou Passenger Dedicated Line.The results were as follows: Gravel filler with suitable amounts of coarse and fine particles is easier to form dense skeleton structures and to achieve excellent mechanical properties and good compaction features;for the well-graded gravel filler,the compaction coefficient corresponding to the porosity specified in norms is low,so it is more appropriate and reliable to use the compaction coefficient as the control index;using the method of reduction factor of initial tangent shear modulus and the method of unloading rebound rate presented by the author,it is found that the compaction factor k=0.90 and k=0.95 correspond to the dense skeleton structure and loose skeleton structure respectively,and the two types of soil structures behave significantly different in strength,deformation and permeability.