The Application of PIBI Waterproof Roll in Subway Engineering

Relative to railway, highway, them belong to the new building in China, Metro waterproofing compared with ground waterproofing has the following characteristics :I, formation stress, deformation is constantly adjusted in the period of subway construction and operation , due to the inhomogeneity of the Strata, resulting in stress and deformation along the tunnel with longitudinal and circumferential distribution is not uniform. II，subway structure usually built below the Underground water level, the structure is surrounded by pressure of groundwater, waterproof materials are slightly damaged may cause leakage, seepage and leakage under water pressure gradually increased. III， Subway excavation and lining irregular, leading to deployment of rugged waterproof layer, which requires waterproofing material must have a large deformation capacity to adapt to irregular structures. IV, primary supporting and secondary lining under rock, be in a State of constant deformation too, waterproof layers must have the capacity to adapt to its deformation. Therefore, Metro waterproofing compared with ground waterproofing， is more complex, more controllable.So, subway construction waterproofing work requirements are higher than ground.

Metro needs the very high-waterproof, generally they are primary or secondary, in the process of subway construction ,waterproof material is crucial. And PIBI waterproofing membrane is precedent, Be used in such as tiananmendong ,dabeiyao, thermal power plant of Beijing subway station ,and in Shenzhen subway station and Tianjin subway station, after many years with no leakage.Easy to see ,the technology is mature, reliable, especially suitable for waterproof project of Metro.

Technical advantages of our company: We did Metro engineering as research projects, through a large number of investigations and experiments in the field, developed a subway special butyl rubber waterproofing membrane and adhesives, combined with years of experience in waterproofing ,And summed up a mature and reliable methods of the underground waterproofing engineering.

Construction specification for butyl rubber waterproofing membrane in underground railway project

Causes of leakage:

1. poor finished product protection.Acquisition of underground sealing material or finished plugging layer,due to the negligence, construction accidentally cause damage and is not patched in time resulting in leakage.

2. insufficient concrete cover thickness.According to the specifications should be thick concrete protective cover, but often because you cannot guarantee the construction cracks, resulting in leakage.

3. No attention to detail structure.Expansion joints and construction joints, after-pouring belt, reserved interface, the underground main structure of concrete and other parts be taken improper sealing measures.

4. Concrete mixture ratio in the construction of underground sealing is inaccurate ,particularly water-cement ratio increases, results in concrete shrinkage, leakage cracks.

5. Concrete curing poor causes early water loss serious, results in leakage.

6. No use underground leakage concrete on concrete retaining structure, and only flexible sealing layer.

Design requirements:

1.Underground waterproof engineering programme, Taking the fundamental principles of prevention as main, discharge as supplement ,should be followed local conditions, advanced design, waterproof, reliable, economical and reasonable.According to the requirements for design of underground waterproof project security table.

2.General design of underground waterproof works, main pressure-resistant for exterior wall or self-waterproof , then do volume material waterproofing applied outside (surface treatment), waterproofing practice, compliance with the relevant provisions of the State construction.

3.Underground works is Complex, we must understand the underground soil, water quality and groundwater, designing with effective security, guarantees waterproof qualities.

4.Underground,when the maximum  water level higher than the ground surface, underground reinforced concrete structure design should take into account the overall, ensure the waterproofing effect.

5.Underground security level determines, based on survey information to provide maximum water level elevation, coupled with the 500mm security elevation, moisture treatment can be done in the upper, surface water follows Security design of waterproofing of underground.

6.Underground water, according to the actual situation, to be used in flexible waterproof or rigid waterproof, rigid-Flex waterproofing programme can be used if necessary.Under the special requirements, you can use multiple fortification programme such as overhead, double wall.

7.When underground waterproofing applied outside face, external control Interface method can be used, there are conditions to prevent externally bonded construction.

8.Underground waterproofing protection, can take a soft layer ,like polystyrene Board and so on.

9.For special parts, like vulnerability parts such as expansion joints,construction joints ,wall pipe and buried , must be carefully designed as required for detailed treatment.

Basic requirements of construction :

(A) preparation

1. before the construction,review the draw , understand underground construction technology of waterproofing details and requirements, prepare underground waterproof project construction plan and technical measures.

2. Underground waterproofing construction procedure shall be governed one by one for acceptance,After passing the next procedure construct.

3. Waterproofing material which be used must has the factory certificate of competency, and waterproof materials certificate.Materials must comply with the design requirements.Waterproof material enters the scene ,each samples  qualified before used according to the regulations.

4. Underground waterproofing works must be Constructed by waterproofing professional team, its technical director and team leaders must have a waterproof construction induction certificate.

5. Construction using the recommended practices must comply with the provisions relating to fire safety and environmental protection in force in the country.

(B) working conditions

1.Base 15-20mm thick 1:3 leveling layer of cement mortar should be sufficient strength.Screeds should erase the calender, solid, firm, not sand, without embossing, loose, bulging, cracking, pockmark and other phenomena. 2m long ruler to check the flatness, gaps between the screed and a ruler should not exceed 5mm.

2.The surface of screeds must be clean, dry, the moisture content is not more than 9%.

3.Floor screeds and vertical wall junction, screeds and water pits, pit junction between Yin and Yang KOK should be made into an arc.Radius should be selected according to type of roll material.

4.Screed slope should be designed to complies with the relevant requirements and provides conditions ,no local water.

(C) considerations

1. Construction materials and auxiliary materials are flammable materials, warehouse and store materials must comply with the national provisions relating to fire safety at construction site.Using solvents such as xylene should have appropriate anti-virus measures.

2. Underground waterproof engineering job, the operators must wear a safety helmet.

3.  Construction environment temperature of PIBI waterproof material is not lower than -10 ℃,In rain, snow, or up five-level wind no construction .

4. Attention to the finished product protection.Waterproof construction and related processes operational collaborate, waterproofing professional team and construction personnel to protect the waterproof layer not be damaged.Do not wear shoes with nails on waterproof layer.

5. labor organization can be adjusted according to construction works,5-8 persons per group in Generally .

Acceptance and warranty:

(A) underground waterproof engineering quality should meet the following requirements.

1. There should be no leakage and stagnant water in the completed waterproofing layer.

2. All material must comply with the quality standards and design requirements.

3. Waterproof layer paving method and roll lap sequence should Comply with the construction technology requirements,  Lapped seam muse be Glue, accurate and strict,The seam edge be Stopping sealed. Be sure that ,Cover bead be bonded solidly, Lapped seam be sealed Coated,Roll surface is Smooth and end head is firmly.

4.  Detail construction practices must comply with the design requirements.

5. Each procedure should have someone to check, In particular concealed works to reach qualified,, Upon acceptance, move on to the next procedure.

6. After the Completion of construction of underground waterproof works, should be finish all the technical information in timely and do the work of archiving.

(B) the warranty period

The warranty period of Underground waterproofing engineering shall be not less than 3 years.Construction unit signed a contract with used units ，when leakage occurs during the warranty period, the construction units are responsible for repair 。the costs borne by the responsible party.