How many levels of integrated pipe gallery engineering waterproofing can be suit

The inevitable and important mission of waterproofing is to prevent the infiltration of all-pervading environmental water into the multi-phase porous system such as reinforced concrete, to avoid causing steel corrosion, concrete corrosion (carbonization, calcium loss and neutralization), to extend the durability of the structure, and to protect the life of the main structure. With the support of the "comprehensive pipe corridor" by the Party and state leaders and multiple departments, the construction is in full swing, and the policy of the "Urban comprehensive pipe corridor Engineering Technical Specifications" issued by the state has been implemented. It is clearly stipulated in the provisions of the code that the structural design service life of the integrated pipe corridor project should be 100 years; The integrated pipe corridor should be waterproof based on climatic conditions, hydrogeological conditions, structural characteristics, construction methods and use conditions and other factors, and the waterproof grade standard should be level 2, and meet the structural safety, durability and use requirements.


So, how many levels can the engineering waterproofing of the integrated pipe gallery meet the policy requirements?
First of all, from the perspective of underground engineering waterproof standards and scope of application, the pipe gallery belongs to the structure, classified as other underground engineering tunnels is suitable, such as the integrated pipe gallery only includes water supply, drainage, gas pipelines (gas alarm system), to meet the level two waterproof standards: do not allow water leakage, the structure surface can have a small amount of wet stains, the total wet area is not greater than the total waterproof area of 2/1000; No more than 3 wet spots on any 100㎡ waterproof area, and the maximum area of a single wet spot is not greater than 0.2㎡; Tunnel engineering also requires the average water seepage is not more than 0.05L/ (M2 × d), any 100㎡ waterproof area of water seepage is not more than 0.15L/ (M2 × d), enough to meet the requirements of use, that is, this kind of comprehensive pipe corridor from the waterproof standard, the design requirements of the second level of fortification is appropriate. However, the integrated pipe gallery usually covers high-voltage cables and weak current cables, and should be set up separately. In the case of wet or water seepage in the integrated pipe gallery structure, it means that the integrated pipe gallery is wet, which is easy to cause corrosion and ignition of high-voltage cables and weak current cables, seriously affecting the normal operation of the equipment at the load end and the safe operation of the project. Therefore, from the point of view of the scope of application and use function, the waterproof forproofing level of the integrated pipe gallery including high-voltage cables and weak current cables should be a level, so that the setting is more scientific, reasonable and safe.


Secondly, from the perspective of the structural design service life of the integrated pipe corridor, article 8.1.3 of the Technical Code for Urban Integrated Pipe Corridor Engineering clearly stipulates that the structural design service life of the integrated pipe corridor project should be 100 years. According to the Ministry of Construction "Concrete structure durability design and construction Guide", according to the durability requirements, the structural design life is divided into 100 years, 50 years, 30 years 3 grades, civil building underground engineering design life is generally 50 years, comprehensive pipe corridor structure design life should be 100 years, should be particularly important, at least important buildings. While the basement of civil buildings is still fortified in accordance with the requirements of waterproof level 1, the waterproof of comprehensive pipe corridor is obviously low in terms of defensive level and does not meet the structural durability requirements.


Thirdly, the durability of underground engineering largely depends on the quality control, quality assurance and maintenance and management during the construction process of the structure, for which the Ministry of Construction published the "Concrete Structure Durability Design and Construction Guide". The guide divides the design service life of the structure into three grades of 100 years, 50 years and 30 years according to the durability requirements, and the design life of underground engineering is generally more than 50 years, so this article adds the provision that "should be based on the durability of the structure". And waterproof design should be accurate, durable and applicable; The waterproof scheme of underground engineering should be determined according to the structural design, material selection and structural durability. Underground engineering should be waterproof design, and should be accurate grading, reliable scheme, simple construction, durable and applicable, economic and reasonable. The waterproof scheme of underground engineering should be determined according to engineering planning, structural design, material selection, structural durability and construction technology.


Due to the porous and multi-phase characteristics of reinforced concrete, it is theoretically a permeable water body with small permeability coefficient. Considering the structural ultimate load design and site construction factors, it is more permeable water body in engineering practice. The erosion and destruction of concrete structures and steel bars by groundwater in underground engineering has become a problem that cannot be ignored. Reliable underground engineering waterproof layer effectively isolate the impact of groundwater on the structure, to ensure the durability of the structure, and the reliability and durability of the waterproof system is from the waterproof grade, waterproof material selection, waterproof layer number of waterproof tracks, waterproof layer thickness, flexible waterproof layer and rigid waterproof full adhesive composite effect, in order to achieve the structure design life of 100 years, Waterproofing shall be fortified according to the first class standard.


In addition, the underground integrated pipe gallery project should be based on the contemporary international standard, and the durability design should be carried out according to the design service life of 100 years and the environmental category during construction, and the seismic design and seismic construction of Class B buildings should be achieved in accordance with the seismic disaster reduction requirements of urban lifeline projects. According to the requirements, the pipeline corridor construction should be good raw material quality, to ensure that the project construction meets the quality acceptance standards; Reduce maintenance and repair costs during operation by taking into account the requirements of optimal life cycle costs.


However, according to the national building leakage survey released by the China Building Waterproof Association, the basement has an average leakage rate of 57.51%, and the underground tunnel has more "ten tunnels and nine leaks", "ten cracks and nine leaks", and the waterproof industry also has embarrassing and humiliating "three 65%", and the underground leakage phenomenon is getting worse. The annual cost of leakage repair is much higher than the cost of new waterproofing. The difference between theory and practice often leads to things not satisfying people's wishes, so it is imperative to improve the waterproof fortification level of the integrated pipe corridor. It is understood that due to the lack of attention to the waterproof project of the integrated pipe corridor, the current leakage phenomenon has occurred in the integrated pipe corridor project in some areas, and the new project has changed into a maintenance project.


To sum up, the waterproof fortification level of the integrated pipeline corridor project should be level 1. It is hoped that the relevant construction units will pay attention to improve the waterproof durability requirements of the integrated pipe corridor, and provide systematic and special waterproof solutions for specific projects to ensure that the "century-old foundation" is evergreen.