How can we try to make the reinforcement time shortest, it is the most important factor we have to consider.
Excavate is impossible, because of it big cost and long time for construction. The best way is repair the tunnel inside of the tunnel, and have to guarantee the strength of the new structure.
The corrugated steel tunnel liner plate is just for the projection like this. It is easily to assemble inside of tunnel, because it is a steel structure, and only connected by bolts and nuts, so we can finish assembling in short time, not like concrete, it needs to wait days as curing period, and it is also be affected easily by whether.
So the corrugated steel tunnel liner plate can make sure the reinforcement job to be finished in short time.
Another factor we have to consider is the strength of the steel structure. On top of tunnel, it is back filling materials, the live load and dead load is on the top of the tunnel. So if we make tunnel reinforcement, we have to consider the load on the top of the old tunnel, and we have to consider the load on the top of new structure.
For each projection, we have to know the details of it, like the span, rise and filling back height, is there any heavy truck or train pass on the top of the tunnel. After getting all details, we can calculation and design the tunnel line plate, we make sure the profile shape, thickness, and calculate its strength again. Then we can start to produce and ship to the job site.
Construction of tunnel liner plate
There are two construction method for corrugated tunnel liner
First is a new tunnel or culvert projection, we can excavate and then assemble the tunnel liner plate on the foundation. After assembling, we fill back the soil or other filling back material layer by layer, compact layer by layer, as same as corrugated steel culvert pipe.
Another way is assemble the tunnel liner plate inside of old tunnel or culvert. Some time, ,maybe one section of the tunnel has disease, then we just repair the damage section is ok. It is easier, just assemble the tunnel liner plate to be a steel structure inside of the damage section, after that we injection the concrete into the gap between the old tunnel and the new corrugated steel tunnel. The repair job is complete.
Some time, we will reinforce the whole existed tunnel. It will take a little long time. We can repair section by section. Every day, we stop the traffic hours, maybe at night, just choose the time that only have few traffics to start assemble the tunnel liner structure. The construction is as same as section repair, but noted that, we have to leave a hole for injection concrete on the top of the tunnel liner structure, maybe 2 rings with one hole, maybe 1 rings with one hole. Because if long section, we can not injection the concrete from outside of the tunnel liner structure, we can injection concrete by the holes, normally the holes diameter is 45mm.
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