Ultra-High Escape Pipe Ultra-High MolecularDN800Outer Diameter Escape Pipe

The escape pipe is located at the second lining end of the tunnel, and the distance from the second lining end shall not exceed 5 meters, arranged from the lining working face to an appropriate position within 30m from the excavation face, with the pipe laid along one side of the initial support towards the face. A working rope is reserved inside the pipe for easy escape, rescue, and communication. How to choose an escape pipe? Currently, the commonly used escape pipes on the market are made of steel and ultra-high molecular DN800 escape pipes. The differences between the two are as follows:

1. Ultra-high molecular is a new type of impact-resistant escape pipe, while steel is the traditional escape pipe used in tunnels.

2. When subjected to external forces, the ultra-high molecular escape pipe can absorb impact energy and return to its original shape without deformation, while the steel escape pipe deforms.

3. The weight of the ultra-high molecular escape pipe is one-eighth of that of the steel pipe, making it easier to transport and install.

4. The price is relatively moderate, with a very high cost-performance ratio, gradually replacing traditional steel escape pipes.

Luoyang Guorun New Materials has adopted a new material for the first time (the new type of tunnel escape pipe is made of ethylene and butadiene monomers polymerized under a catalyst, with an average molecular weight of over 2,000,000 and a linear structure thermoplastic engineering plastic.) Design research has been conducted on emergency rescue passages for highway tunnel construction. Combining ergonomic principles with the Hertz contact mechanics theory, the dimensions of the structure of the new type of tunnel escape pipe were optimized, and the connection method of the passage was designed. Through impact resistance tests, the reliability of the new type of tunnel escape pipe for emergency rescue in highway tunnel construction was verified.

The reliability of the new type of tunnel escape pipe was verified through the following 4 basic methods

1. Design of structural dimensions of the escape pipe (new material) in Sichuan tunnels

    According to the research results of ergonomics by the American expert Alvin R. Tilly, it is known that when crawling, the most comfortable crawling height is 725mm and the crawling length is 1520mm, as shown in Figure 2.

Figure 2 Ergonomic Requirements During Crawling. Alvin R. Tilly pointed out that when crawling through the circular opening of the full-body entrance and exit, the small diameter of the circular pipe must be 585mm. Therefore, the inner diameter of the new emergency rescue passage for highway tunnel construction must be ≥585mm to ensure normal passage of the human body. At the same time, considering the actual situation of the highway tunnel construction site, the outer diameter of the emergency rescue passage should not be too large, otherwise it will have a significant impact on construction. Hence, the outer diameter of the ultra-high molecular weight polyethylene pipe is set at 636mm.

2. Design of wall thickness and diameter of the new type of escape pipe in Sichuan tunnels

    Thin-walled circular pipes experience minor overall bending deformation during lateral impacts from large energy blocks on the top of the tunnel, with deformation primarily localized at the impact point. The values of different wall thicknesses H were calculated; as the wall thickness of the circular pipe increases, the deformation caused by the falling block decreases. When the height of the falling block h = 7m, and the wall thickness H = 24mm, the deformation value of the Sichuan tunnel escape pipe is Δ = 0.048m, which is about 8% of the diameter of the circular pipe; when the height of the falling block h = 5m, and the wall thickness H = 24mm, the deformation value Δ = 0.038m, which is even smaller. At this time, after deformation, the passage space inside the escape pipe is 740mm, satisfying ergonomic requirements for safe passage. When the wall thickness is small, the deformation value increases, which may be unsafe; when the wall thickness is larger, although safety increases, the weight of the pipe also increases, leading to higher costs and difficulties in handling. Therefore, a wall thickness of 30mm for the escape pipe is appropriate in the design.

3. Design of connection components for Sichuan tunnel escape pipes

     The main body of the tunnel escape pipe uses a new type of tunnel escape pipe, with a reinforced protective layer at the end. The connection components include steel wire ropes, iron chains, and hooks at the ends. To facilitate climbing in the escape pipe during tunnel collapse accidents, a climbing rope is tied every 120° around the passage. Following the principle of easy assembly and disassembly, the connection method between the highway tunnel escape pipes is a clamp connection. Thus, it is convenient during installation; for the first installation, simply align and secure the two pipes with a clamp, then drill holes through the pipe at existing holes of the clamp for bolts. The ends of the steel wire rope and iron chain are hooks; the length of the iron chain can be freely adjusted based on the tightness at the position where the hook fastens on the iron chain's ring.

4. Reliability verification of the tunnel escape pipe

    The thin-walled circular pipe used for tunnel escape is freely placed on a flat cushion. When subjected to impact loads from falling rocks, the bottom of the circular pipe is primarily constrained by vertical and horizontal friction from the cushion. The distance from the impact specimen to the top of the circular pipe mainly depends on the excavation height of the tunnel section. This experiment takes the extreme height H from the center of the tunnel top to the top of the circular pipe as 10m. The falling block is released freely, and impacts are conducted on both the tunnel escape pipe and the steel pipe. The experimental results show that after impact, the stone is ejected from the tunnel escape pipe, which sustains almost no damage and demonstrates good impact resistance; the steel pipe, however, gets crushed and deformed upon impact.

Conclusion of Certification:

Because the tunnel escape pipe is lightweight, easy to assemble and transport; the pipe has good toughness and high impact strength. When subjected to strong external impacts, it instantaneously deforms, absorbing a large amount of impact energy, and then quickly returns to its original shape, providing extremely safe protection for emergency rescue in highway tunnel construction; the pipe has high ring stiffness, good pressure resistance, and is not easily deformed. In the event of a collapse during highway tunnel construction, its load-bearing capacity and resistance to environmental damage far exceed that of ordinary pipes, including steel pipes.

Luoyang Guorun New Material Technology Co., Ltd., welcomes customers to visit and inspect the factory!

Sales Manager: Manager Sun (Technical Consultation＋Factory Services 

Contact Information:136 9888 7149   0379-65227507   

Factory Address: China.Luoyang Airport Industrial Cluster.Zhejiang Business Industrial Park