Waterproof board is the key to waterproof composite lining of tunnel
The waterproof board is the key to the waterproof composite lining of the tunnel, and its quality directly affects the waterproof function. With the increasing awareness of environmental protection, the importance of tunnel waterproofing is self-evident. The waterproof level of a high-speed railway tunnel is required to be level one: the lining is impervious and not wet. For road tunnels, the traffic function has higher requirements for waterproofing. With the continuous development of society, the requirements for waterproofing will become higher and higher.
During the laying process of the tunnel waterproof board, level the surface of the first sprayed concrete, take measures to drain the moisture of the paving base surface and lay the cushion (geotextile) to make the waterproof board have good laying conditions. The waterproof board is laid by hot-melt welding technology, and an automatic welding machine is used to make the weld seam well-sealed and high in strength, thereby ensuring the integrity and waterproofness of the waterproof board.
Since there is a smooth surface waterproof board between the primary support shotcrete and the secondary lining formwork concrete, it can eliminate and weaken the friction constraint of the primary support shotcrete to the secondary lining concrete, make it freely deform or reduce the binding force, The tensile stress generated by the secondary lining concrete is less than the tensile strength of the concrete, and the secondary lining formwork concrete will not produce tensile strain cracks, thereby ensuring the overall waterproof performance of the tunnel. Therefore, the laying quality of the waterproof board not only affects its own waterproof effect but also directly affects the overall waterproof effect of the later secondary lining concrete.