水稳基层水泥路面层间剪切刚度的实测与修正

Interface shear stiffness test and correction for cement concrete pavement with cement stabilized crushed stone base

为准确表征水泥混凝土路面基-面层层间接触参数,研发了可反映层间法向压应力差异的水平剪切试验仪,分2个阶段测定了层间经乳化沥青、土工布和沥青混凝土夹层等3种措施处置的水泥稳定碎石基层水泥混凝土路面的层间粘结-滑移曲线;通过回归分析建立了层间平均剪切刚度和法向压应力的关系模型;采用试算法确定了当量单圆荷载下层间剪切面的大小,并基于简单迭代法对层间平均剪切刚度进行了压应力修正,最终推荐了3种层间处置措施下的层间当量剪切刚度。研究结果表明:Ⅰ阶段的剪切试验中,层间使用乳化沥青处置的试件克服层间粘结所需的剪力最大、土工布次之、沥青混凝土夹层最小,基-面层粘结状态与层间处置措施显著相关,并直接影响着路面的结构行为,层间处置措施选择时需要在降低面层荷载应力和温度应力之间寻求平衡;与Ⅰ阶段的剪切结果相比,Ⅱ阶段的剪切试验中,3种试件的抗剪能力均显著减弱,平均剪切刚度大幅下降,不同使用阶段的路面结构层间剪切刚度差异巨大,路面结构分析时层间抗剪参数的选择须与使用状态相适应。

In order to accurately characterize the i concrete slabs and base, the horizontal shear tester stress. The bond stress-slip curve of cement stabi specimen in which the interface treated with emulsi interlayer was determined in two stages. Then th nterface contact parameter between cement was invented which can simulate the vertical lized crushed stone base concrete pavement fled asphalt, geotextile and asphalt concrete e relationship model between average shearstiffness and vertical compressive stress was established by regression analysis. The size of the interface shear area under the equivalent of a single round load was determined by trial algorithm. Compress stress correction was made for average shear stiffness based on simple iterative method. Equivalent shear stiffness of the three interlayer disposal measures was recommended. The results show that in the first stage of shear test, specimen interface treated with emulsified asphalt requires the maximum shear stress, geotextiles requires little and asphalt concrete is minimum. The interface contact state between slab and base is significantly related to the interface treatment measures, and it has a significant effect on the structural behavior of pavement. So, the interface treatment measure selection needs to find a balance between flexural stress and thermal stress of slab. Compared with the test results of stage one, in the second stage, shear capacity of the three kinds of specimens are significantly weakened and the average shear stiffness decline dramatically. The difference between interface shear stiffness of pavement structure is tremendous in different using stages, so the interface shear parameter selection must adopt the using state of pavement in structural analysis.