十多年来我国沿用着以弯沉为指标的柔性路面设计方法。众所诸知,弯沉只是表征路面整体强度的一个综合性指标。只一个弯沉指标并不能充份表征路面在车轮荷载下的应力状态。如图1的两种路面结构,弯沉值相同,但弯曲程度(用层底拉应力或曲率半径表示)不同,路面1比路面2就处于更不利的应力状态(σ_(r_1)>σ_(r_2))。 For more than a decade, our country follows the design method of flexible pavement with deflection as an index. As we all know, deflection is only a comprehensive indicator of the overall strength of the pavement. Only one deflection indicator does not fully characterize the road surface under the wheel load stress state. The two pavement structures in Fig. 1 have the same deflection values ​​but the degree of bending (indicated by the tensile stress or radius of curvature of the bottom layer) is different from that of pavement 2 in that it is in a more unfavorable stress state (σ_ (r_1)> σ_ r_2)).