半刚性基层双层连续摊铺层间结合状态
Interlayer combination state of double-layer continuous paving semi-rigid base

为了提高寒冷地区道路基层使用寿命,研究了半刚性基层层间黏结机理,设计了适用于基层试件的直剪模具,对基层层间抗拉强度和抗剪强度进行试验,分析了不同摊铺方法对基层层间结合效果的影响。运用BISAR3.0软件,设定了不同的层间摩擦因数,在不同层间结合状态下计算了各结构层层底拉应力分布情况,提出了适用于北方寒冷地区沥青混合料与水稳碎石混合料的疲劳方程,计算了双层连续摊铺工艺下路面的使用寿命。计算结果表明:采用双层连续摊铺时,基层试件层间抗拉性能较传统试件提高了1.8倍,但仅达到了标准试件抗拉强度的37.9%,双层连续摊铺距离层间结合理想状态(完全连续)还有一定的差距; 在抗剪强度上,双层连续摊铺相比于传统摊铺工艺提高了7.3倍,采用双层连续摊铺施工可以有效改善基层路用性能; 随着层间摩擦因数的提高,各结构层层底拉应力不断减小。可见,双层连续摊铺可以有效提高半刚性基层层间结合效果,改善层底应力分布,使路面结构寿命提高了16.1%～47.4%。
In order to improve the service life of road base in cold area, the bonding mechanism of semi-rigid base was studied, and the direct shear mould for base layer specimen was designed. Based on the tests of tensile strength and shear strength of base layer, the influences of different paving methods on the combination effect of base layer were analyzed. By using software BISAR3.0, different interlayer friction coefficients were set, the distributions of tensile stress at the bottom of each structure were calculated under different interlayer combination states. The fatigue equations of asphalt mixture and water stable crushed stone mixture suitable for northern cold area were put forward, and the service life of pavement under double-layer continuous paving process was calculated. Calculation result indicates that when using double-layer continuous paving, the tensile property of base layer specimen increases by 1.8 times compared with traditional specimen, but only 37.9% of the tensile strength of standard specimen is achieved. There is a certain gap between double-layer continuous paving and ideal state(completely continuous). For the shear strength, the effect of double-layer continuous paving increases by 7.3 times compared with traditional paving process. The performance of road base is effectively improved by using double-layer continuous paving construction. With the increase of interlayer friction coefficient, the tensile stress at the bottom of each structure decreases. Therefore, the combination effect of semi-rigid base layer can be effectively improved by using double-layer continuous paving, which can improve the stress distribution of the bottom of layer and increase the service life of pavement structure by 16.1%-47.4%. 15 figs, 25 refs