Abstract 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 proposes 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 polyurea 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-applied 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, indicating that the bonding strength between the spray-applied polyurea membrane and the concrete surface of the tunnel 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.
Abstract：
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 proposes 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 polyurea 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-applied 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, indicating that the bonding strength between the spray-applied polyurea membrane and the concrete surface of the tunnel 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.
WANG Song1 YANG Changyu2 XU Xingwu1 LI Chuanfu1 WANG Jushan1 YUAN Xun2 WANG Fang2CHEN Ang2 YANG Yi1 WANG Hui1 GUO Jijun1 GUAN Qiang3 WANG Fuhai3 LIU Qiang1SUN Cheng4 ZHANG Yongqin4
.An Experimental Study on the Application of Spray-applied Polyurea Membrane in Remediation of Tunnel Lining Spalling[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(2): 282-292
2023, Vol. 60 