Tunnel Type PVC Membrane

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Tunnel Type PVC Membrane

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WHAT IS CPC?

Tunnel Boring Machine (TBM), which comes from English as the origin of the word, has a structure as you can see in the picture of this technology, which enters the field of excavation mechanization of mining engineering, which is used to shorten distances to eliminate traffic problems, especially in metropolitan areas with high population density.

AVRASYA TUNNEL – TBM
TBM is a circular excavation machine that can drill in various rock and sand formations with a diameter of 1 meter (micro tunneling) up to 19 meters. It is cleaner and faster than the traditionally used drilling and blasting method, and it is also suitable for opening long tunnels. Negative aspects are very high cost.

WHAT IS NATM?
NATM, or The New Austrian Tunnelling Method, is an excavation method using the drilling and blasting method in tunnel projects mentioned in the engineering literature.

Prof. L.v. Rabcewicz gave the following definition for NATM when he applied for a patent in 1948:” “It is the reduction of rock pressure by placing a thin temporary support and allowing deformations and distributing this pressure to the surrounding rock. In this way, the final support will be less loaded and then the final support can be placed in an even thinner structure. Deformations should be monitored by measurements and the results should be evaluated in conjunction with structural analysis and design.” After the completion of drilling and strengthening of the tunnel or underground structure according to the TBM or NATM method, waterproofing should be applied. Before the waterproofing application, the surface should be at least 5 cm thick and the cavities and protrusions formed on the surfaces should be minimized with a shotcrete application with as smooth a surface as possible. After the rough filling on the surface with shotcrete, if necessary, correction should be made with top coat fine aggregate and top coat concrete with the necessary chemical additives. In the entire section to be covered, first of all, after the drainage lines at the base are formed, layers will be formed on the poured grobeton as listed below. Geotextile felt (100% Polypropylene Highways Technical Specifications)
Tunnel Type PVC Membrane with Signal Layer
Geotextile felt (100% Polypropylene Highways Technical Specifications)
After waterproofing is done on the drainage lines, at least 5 cm thick protection concrete should be poured and base concrete production should be started. After the base concretes are completed, tunnel scaffolding should be installed and waterproofing of the tunnel spring should be started. After the surface is made smooth with shotcrete application, minimum 500gr/m2 geotextile felt should be laid in accordance with the Highways Technical Specifications. By making 7-10 cm bini, the entire area to be applied and the geotextile felt from the base should be fixed with the geotextile felt by means of washers and the geotextile felt laying should be completed. After laying on the geotextile felt by welding with the washers used in the placement of the geotextile felt on the inner surface of the tunnel with the help of Tunnel type PVC membrane welding machines, Tunnel type PVC membrane is sewn with double seam welding fusion robot by making 7-10 cm overlap. After careful sewing, it is combined with the material coming from the base and waterproofing is completed. The contractor pours the appropriate dose of coating concrete and the tunnel is finalized. If the spring concrete will be reinforced, the insulation layer should consist of 2 (two) layers of geotextile felt and a single layer of PVC membrane. If it will be unreinforced, the second layer of geotextile felt may not be needed on the inner surface.

1.Why tunnel type membrane with signal layer should be used in tunnel applications? What is the working system of the signal layer?
The signal layer used in the tunnels is a light colored (yellow, white, etc.) layer with a thickness of about 0.7mm laminated on PVC membrane and contributes to the illumination inside the tunnel, as well as ensuring that any tears and punctures that may occur on the membrane can be easily detected by visual inspection. Since tunnels are high volume areas, it is not possible to open and inspect the entire structure up to the insulation layer in case of damage to the insulation material. The signal layer allows for regional renovation by revealing the dark colored membrane in the substrate due to the penetration of the damaged area.

2.How and how often are material conformity tests performed?
Material conformity tests are carried out at the Laboratory of the General Directorate of Highways (Ankara) by taking samples from each shipment sent to the construction site under the control of engineers authorized by the Highways. It is of high importance for the implementing company that the test results are archived until the provisional acceptance and final acceptance are completed and that they can be declared to the relevant authorities when necessary. Otherwise, it will constitute a problem in the registration of the conformity of the material as a result of a damage that may occur.

3.PVC membrane welding is done? Is torch flame a suitable method?
After the ground suitability conditions are met in PVC membrane applications (according to the application technical specifications), a minimum of 500 gr / m2 polypropylene geotextile felt 7-10 cm overlap should be made and the entire area to be applied and the geotextile from the base should be fixed by means of washers. After laying on the geotextile felt by welding with the washers used in the placement of the geotextile felt on the inner surface of the tunnel with the help of Tunnel type PVC membrane welding machines, Tunnel type PVC membrane is made 7-10 cm overlap and sewing process is started with double seam welding fusion robot. After careful sewing, it is combined with the material coming from the base and the insulation is completed. The torch flame is not used because it will burn and melt the material.

4.How is the scaffolding used in tunnel applications different from other scaffolds?
The scaffolds used in building restorations or new constructions that we see around us are standard and are suitable for the use of the same scaffold for different sites, provided that the required width and height are provided as a result of mounting on the building surface and adding the parts to each other. In tunnel scaffolds, static calculations are made according to the arc length of each tunnel and special manufacturing is made.

5.Are the dimensions and roll length of PVC membrane rolls standard?
Tunnel PVC membranes are specially produced in desired lengths according to the arc length of the tunnel, with bini stripes on the edges and axle stripes in the middle for ease of application.

6.What are the advantages of PVC tunnel membrane with signal layer?
The raw materials used in production are 100% original and environmentally friendly products suitable for recycling are offered to the user. In addition to the roll sizes that can be produced in a wide range, rolls can be supplied in desired lengths in accordance with the tunnel diameter, providing fast and economical application.

7.What should be the characteristics of the accessories that should be used in the application?
Washers used in the application must be compatible with PVC geomembrane, metal washers are not used in tunnel linings, washers must be PVC based in order to fix the materials to each other. Geotextile felt should be made of 100% polypropylene material and minimum 500 gr/m2.

8.How should the nail guns used for fixing the washers be?
There are two types of nail guns: pneumatic and gunpowder. The pneumatic nail gun is more preferred than the gunpowder nail gun because it allows efficient operation in humid environments.

Tunnel Type Signal Layer PVC Membrane Application Areas

New tunnel construction Repair of existing tunnels Road tunnels Railway tunnels Cut and cover tunnels NATM construction tunnels Drill and blast tunnels Metro stations Cable tunnels TBM tunnels Tunnel Type Signal Layer PVC Membrane Benefits Simplified tunnel lining
Reduced material and labor costs
Reduced installation requirements
Improved drainage capacity
Reduced calcification risks
Minimal damage from mineral calcification
Underground construction methods can be used for the construction of deep (> 20 m) and shallow tunnels. All construction work in tunnel structures is carried out underground. To protect tunnel structures from the influence of groundwater and to prevent excessive moisture from penetrating into the tunnel interior, a tunnel-type PVC geomembrane is used, which is used as a special waterproofing layer.

Advantages;
High elasticity
Biological stability
Abrasion, tear and water resistance
Durability
Water tight
It has the durability of the soil / water mixture on the surface, including the chemicals it contains.
Bridges spontaneous crack formation without losing its working capacity.
It can be thermally welded
It has low flammability.
Can be laid on damp or wet surfaces
Tightness and mechanical strength of seams can be controlled safely and economically
Simple and safe to repair
Proper waterproofing of tunnels, galleries and shafts is one of the most cost-effective ways to increase the service life of these structures and improve safety and function. Water infiltrating the structure hinders and jeopardizes the work, especially due to freeze/thaw action. Pouring concrete or block, icicles and effluorescence or stalactites are all evidence of a tunnel with no waterproofing or a poorly designed system. PVC waterproofing membranes are particularly favored for their high resistance to aging and excellent elongation and tensile properties. The application and seam requirements ensure a completely secure and sealed installation.

The Most Important Features of PVC Tunnel Membranes are as follows;

Resistance to aging and decay even under the influence of water containing aggressive elements
High mechanical strength and load resistance
Logical and efficient installation