聚脲喷膜材料在隧道衬砌掉块病害整治中的试验研究

An Experimental Study on the Application of Spray-applied Polyurea Membrane in Remediation of Tunnel Lining Spalling

针对传统掉块病害整治工艺施工工序复杂、劳动强度大、施工速度慢、工效低和费用高等缺点,提出采用聚脲喷膜材料对隧道衬砌掉块病害进行整治。通过对聚脲喷膜材料承受掉块自重和空气动力学荷载的理论分析,以及现场建立隧道衬砌模型的实测试验,重点研究了聚脲喷膜材料的粘结强度和拉伸强度。试验表明,在试块自重和空气动力学效应约14 t荷载的共同作用下,厚度为5 mm的聚脲喷膜材料未发生拉伸断裂破坏,能够承托住衬砌掉块;加载过程中试块周边一定范围内的喷膜材料发生了剥离,表明剥离范围内喷膜聚脲材料与隧道衬砌混凝土表面之间粘结强度逐步降低。为防止隧道衬砌拱部掉块,可采取增加喷膜材料与混凝土之间的粘结强度或增加喷膜材料厚度等措施。

In view of the shortcomings of the traditional remediation process of spalling failures,such as complex construction process,high labor intensity,slow construction speed,low efficiency,and high cost etc.,this paper pro⁃poses to use spray-applied polyurea membrane to remediate spalling failures of tunnel lining.The study carries out a theoretical analysis of the spalling block weight and aerodynamic load accommodated by the spray-applied poly⁃urea membrane and establishes an on-site tunnel lining model for an actual measurement test,with a focus on the bonding strength and tensile strength of the spray-applied polyurea membrane.The test shows that the spray-ap⁃plied polyurea membrane with a thickness of 5 mm does not break in tension under the joint action of the weight of the test blocks and the aerodynamic effect with a load of about 14 t,and is able to support the spalling of the lining.During the loading process,the spray-applied membrane peels within a certain range around the test blocks,indi⁃cating that the bonding strength between the spray-applied polyurea membrane and the concrete surface of the tun⁃nel lining within the peeling range gradually decreases.It is recommended to take different measures to prevent the spalling of the tunnel vault lining,such as increasing the bonding strength between the spray-applied membrane and concrete or raising the thickness of the spray-applied membrane.