the cord fabric Rubber sheet It is a sealing device for the exit of shield machines and pipe jacking machines that are widely used at present, The exit sealing device used in the "double replacement method of box culvert jacking in of underground three-dimensional traffic engineering" is the cord rubber plate. Due to the restriction of the head section shape of the pipe jacking machine, the design of the cord rubber plate of the rectangular pipe jacking machine is different from that of the circular pipe jacking machine and the shield machine. When the shield machine and pipe jacking machine pass through the portal, the portal is annular steel plate There is an annular gap between the shield machine, pipe jacking machine shell or the outer wall of lining segment. If there is no sealing, the external soil and water will easily flow into the working shaft from the gap, which will cause serious soil loss outside the tunnel for a long time, leading to soil settlement. Therefore, a tunnel device must be installed at the portal to ensure construction safety.
（1） The shield tunneling device includes cord rubber plate, annular plate, sector flap and corresponding connections Bolt and Washer : The installation sequence is round plate sector flap of cord rubber plate.
（2） Production of cord rubber plate: the radial nylon lines are densely arranged around the hole of cord rubber plate, and the horizontal cotton lines are sparsely arranged. The cord rubber plate is pressed in blocks by the mold and then connected into a whole frame.
（3） Basic principle of cord rubber plate:
The shield tunnel exit device includes cord rubber plate, circular plate, sector plate and corresponding connecting bolts and washers. The installation sequence is cord rubber plate, circular plate and sector plate. After the installation is completed, the round plate forces the cord rubber plate to cling to the hole through the connecting bolts. In the process of shield propulsion, the cord rubber plate forms a sealing water stop along with the outer wall of the shield. At this time, the sector shaped plate will press against the cord rubber plate after overturning to prevent the reverse overturning of the cord rubber plate caused by excessive water and soil pressure in the front; Under the effect of water and soil pressure in front, the rubber plate will also be close to the sector plate,
This sealing state is relatively reliable.
Construction method of cord rubber plate:
1、 hole door Before the waterproof sealing construction, check the integrity of the materials, especially whether the cord rubber is intact, the radial nylon wires are densely arranged and the bolt holes are intact.
two Before installation, clear the muck at the hole and dredge the hole of embedded steel plate and apply grease.
three Screw the stud bolt into the nut around the pre buried well ring.
4、 Install the cord rubber plate and ring plate, and fix them on the shaft wall with thin nuts.
5、 Put the sector flap on the bolt with thin nut.
6、 Pay attention to adjusting the position of sector steel according to the two stages when the shield passes through the tunnel circle and starts.
Quality assurance measures ：
1. Meet the requirements of design and specifications.
2. The welder must have a work license, and be trained and qualified before work.
3. Check the rubber cord fabric in strict accordance with the specifications to ensure the quality of the cord fabric. During installation, rubber washers are added on both sides of the bolt to achieve better sealing effect. Ensure that all bolts are tightened without omission. After installation, the scaffold shall be restored with quality and quantity guaranteed.
4. Prevent damage to cord rubber plate when installing sector pressing plate
5. Check whether there is any bulge on the surface of the shield head shell. If there is any bulge, clean it up and apply butter on the surface of the head shell to avoid tearing the cord rubber plate and facilitating the jacking of the shield machine
6. The installation size of the rubber curtain cloth plate must be within the control range to effectively stop water 。
7. Since the cord rubber plate and sector pressure plate are closely attached to the segment to prevent the slurry from flowing out during grouting at the back of the segment, the bolt must be tightened twice during installation.
