Subway Tunnel

Tunnel waterproof board products are a new type of special product recently developed by the company that is suitable for the tunnel waterproof construction process. The production process of this product adopts the domestic advanced three-layer co-extrusion blow molding method. The raw material resin EVA or HDPE is added with a small number of functional additives, and the membrane material formed after heating, melting, plasticization, inflation, ring-blowing cooling, and traction is thermally synthesized with the geotextile (signal layer) with slings to form a composite waterproof board. The extrusion calendering method can also be used, that is, the resin extruder is melted and plasticized, and the molten sheet is extruded from the die of the die head integrated with the sling, and then cooled by roller calendering to form a light film, or it is integrated with the geotextile (signal layer) with slings, and then cooled by roller calendering to form a waterproof roll (waterproof board).

According to the construction method, it is divided into self-adhesive construction; waterproof membrane construction with hot melt or hot melt adhesive
1、Concealed buckle tying and hanging (tie suspension method).
2、Anchor gasket fixing method (hot melt gasket anchor welding) and concealed buckle tying and hanging method (tie suspension method);

1、Welding method of waterproofing roll
For the uneven parts existing in the initial support surface, use cement mortar to smooth them.

2、Welding before hanging
Put the narrow rolls of factory-made products flat on the ground and weld them into large rolls that are easy to transport and hang. When welding, the geotextiles of two geosynthetics should be welded together. The geotextile board surface and geotextile should not be welded together to prevent the crack water from penetrating through the geotextile at the joint and causing leakage.

3、Hanging of waterproofing materials
Adopt the hanging method of “from top to bottom” and “trial positioning”. “From top to bottom” means that the waterproofing material is first laid from the ground at the edge of the net to the top, and then the top is closed. This method is more suitable for large-section tunnels, high clearance, large amount of waterproofing materials required, and large rolls.

4、Post-laying connection
Weld the joints between the laid waterproof materials.

5、Protection of waterproof materials
When the lining is excavated immediately, protective measures should be taken for the reserved waterproof materials at the ends of the lining to prevent flying stones from breaking the waterproof materials when the support surface is blasted. The installation of lining reinforcement steel bars, the installation of various embedded parts, the installation of the head membrane plate, the placement of concrete delivery pipelines and the pouring of concrete are likely to cause the waterproof board to be broken, punctured or burned. Once the waterproof board is damaged, it should be repaired immediately.

Before welding the coil, the weld should be kept clean, and free of oil, sand, and clear water. If there is any, it should be cleaned before welding. To ensure the quality of the weld, the requirements for creeping welding machines and manual welding are the same.

Manual welding: is divided into pre-welding, trial welding, and final welding. Manual welding is the high-temperature hot air generated by a handheld electric heating welding gun to melt the surface layer of the overlap of the waterproof coil and roll it with a roller to fuse the two coils into one.

The laying of the waterproof board should be ahead of the construction of the inner lining concrete, the spacing should be 5-20m, and a temporary baffle should be set to prevent mechanical damage and electric sparks from scalding the waterproof board.