嵌锁块路面受力特性与设计方法

为了提高传统路面嵌锁块尺寸与嵌锁块竖向嵌锁能力, 开发了大尺寸企口连接嵌锁块, 分析了其受力特性。以有限元方法建立了嵌锁块路面整体模型, 以弹簧单元模拟嵌锁块间传荷能力, 分析了嵌锁块尺寸、嵌锁块传荷能力、碎石基层厚度与路基强度对路表弯沉和路基顶面竖向压应变的影响。以路基顶面永久应变为控制指标, 建立了路基顶面应变水平与标准累计轴次的关系。计算结果表明: 在相同地基和基层条件下, 嵌锁块尺寸由30cm×20cm增大到50cm×30cm时, 路表弯沉可减小25%~30%, 路基顶面压应变可减小25%~45%。当接缝弹簧弹性系数由102 N·m^-1增加至108 N·m^-1时, 路表弯沉降低50%~55%, 路基顶面压应变降低65%~75%。可见, 采用较大尺寸的嵌锁块与加强嵌锁块的传荷能力对提升路面性能有显著作用, 路面设计时应依据道路的交通水平查图确定路基顶面的压应变水平, 据此确定合理的基层厚度和嵌锁块尺寸, 使路基顶面竖向压应变满足要求。

Mechanical characteristics and design method of interlocking concrete block pavement

In order to improve the sizes and vertical interlocking ability of interlocking concrete block for traditional pavement, the larger-size interlocking concrete block with rabbet joint was developed, and its mechanical characteristics were studied. The finite element model of interlocking concrete block pavement was set up, the load transfer efficiency between interlocking concrete blocks was simulated by using spring element, and the influences of block sizes, load transfer ability, thickness of granular base and subgrade strength on permanent settlement and vertical strain at the top of subgrade were analyzed.The permanent deformation of subgrade was adopted as control index, and the relationship between normative accumulated axle-load acting number and vertical strain at the top of subgrade was established.Computation result shows that based on the same conditions of base and subgrade, when block sizes increase from 30cm×20cm to 50cm×30cm, pavement deflection decreases by 25%-30%, and subgrade strain decreases by 25%-45%.When the elastic coefficient of rabbet joint increases from 102 N·m-1 to 108 N·m-1, pavement defection decreases by 50%-55%, and subgrade strain decreases by 65%-75%.So the larger-size block with stronger load transfer ability can greatly improve the mechanical characteristics of pavement.In pavement design, the stain level at the top of subgrade can be determined according to the traffic condition of road, based on which the thickness of base layer and the sizes of interlocking concrete block are reasonably designed so that the stain level meets the requirement.