高寒地区高速铁路全断面沥青混凝土防水封闭层抗裂措施研究

为了减小轨道板伸缩缝处温度应力对高速铁路全断面沥青混凝土封闭结构耐久性的影响,本文在京张高速铁路现场试验段采用了2种工程措施:在轨道板伸缩缝和沥青混凝土上面层之间设置复合土工膜;在沥青混凝土层与级配碎石层间设置钢钉。研究了轨道板温度应力对沥青混凝土拉伸应变的影响,并验证了2种措施的有效性。试验结果表明:无工程措施时伸缩缝处沥青混凝土弯拉应变约为600×10-6;在沥青混凝土上面层设置两布一膜后弯拉应变约为400×10-6,在此基础上对沥青混凝土下面层施作钢钉,则弯拉应变减小为140×10-6。

Study on Anti-crack Measures of Asphalt Concrete Waterproof Sealing Layer for High Speed Railway in Alpine Region

In order to reduce the inf luence of temperature stress at expansion joint of track slab on the durability of whole section asphalt concrete sealing structure of high speed railway,two engineering measures were adopted in the f ield test section of Beijing-Zhangjiakou high speed railway,including setting composite geomembrane between expansion joint of track slab and upper layer of asphalt concrete,and setting steel nails between asphalt concrete layer and graded crushed stone layer.The effect of temperature stress of track slab on tensile strain of asphalt concrete was studied,and the validity of the two measures was verif ied .The test results show that the f lexural tensile strain of asphalt concrete at expansion joint is about 600×10^-6 without engineering measures,and that the f lexural tensile strain of asphalt concrete is about 400×10^-6 after two cloth and one membrane are laid on the upper layer of asphalt concrete.On this basis,when steel nails are applied to the lower layer of asphalt concrete,the f lexural tensile strain decreases to 140×10^-6 .