Underground utility tunnel structure expansion joint Leakage stoppage maintenance treatment method
The company adopts imported high-tech nanometer Micro molecular waterproof materials, accurately prepare a new technology of scientific pressure reducing grouting, and control various underground engineering leakage, especially for tunnel mass concrete crack leakage, settlement expansion joint leakage and plugging, have many years of experience in maintenance and treatment, and fully have the ability to plug the leakage of difficult tunnels.
Refer to:
1. Grouting sealing water filling:
The technology of "short section micro pressure and re grouting" is adopted for the bottom slab of the sprinkler tunnel. The slurry is prepared with composite polymer slurry, with a water cement ratio of 0.8:1. This sodium free dense slurry is used to inject into the culvert bottom slab.
2、 Elevator. Plugging treatment for internal and external walls of the well:
Two pieces of self waterproofing shall be plastered on the inner and outer walls of the elevator shaft mortar , ratio 1:2.5, mortar cement The skin of the part shall be chiseled off, the component shall be wet, and attention shall be paid to cleaning sodium precipitates, impurities, dust, etc. The plastering shall be carried out twice, with a thickness of 1cm each time and an interval of 2h. After the second plastering, it shall be polished and cured for 5 days. The reinforced waterproof agent is an inorganic material with good adhesion and 40% mortar. It has good corrosion resistance and can effectively resist corrosive media in sewage.
3. Water leakage repair of expansion joint:
The original poorly bonded concrete and rubber waterstop shall be chiseled away 6cm wide, the rubber waterstop shall be taken out, R-3 type self waterproof concrete shall be prepared, and the rubber waterstop shall be re bonded. The impermeability grade of concrete is greater than S12, and the bonding strength is 4.3 MPa, which can effectively supplement the damaged expansion joint gap.
The degree of leakage stoppage and maintenance of expansion joints of underground utility pipe gallery structures can be divided into the following situations: leakage of through wall pipes and embedded parts. The main reason is that there are micro cracks on the contact surface between pipeline and embedded parts and concrete.
1. Slight seepage: the concrete surface is wet and wet, and there is water when touching by hand. There is no reflective water trace under the light;
2. Slow seepage: the concrete surface is wet and watermarked, touch the water with your hand, wipe the seepage part dry, and after a period of time, the reflective imprint of running water can be seen;
3. Water leakage: Wipe the leakage surface dry, and it can be seen that there is water seepage immediately on the leakage place. The water drips under the roof or into a line, the water drips on the wall, and the water accumulated on the floor. There is a large amount of water leakage, some of which are in the shape of small cages, and the water leakage is 50/min.
Analysis on the causes of leakage of expansion joints of underground utility tunnel structures for leak stoppage and maintenance:
1. The quality of concrete porcelain building is poor and the workability is not good. The heavy particles in the aggregate are settled and solidified, and the pores in the concrete flow away from water more and concentrate. When the water is continuously flowing, the concrete structure has a large amount of water absorption, which accelerates the internal chemical corrosion and forms a large area of leakage.
2. The alkali content of cement aggregate is high, especially when an admixture with high alkali content is used, when the cement is hydrated, a large amount of N exfoliation will occur, resulting in self corrosion of structures from the inside out, corrosion of steel bars, resulting in concrete surface falling off and continuous water seepage.
3. There is a gap between some reinforcement and concrete, which increases the erosion of water on reinforcement.
4. There are several leakage points at the bottom of the bottom plate, and the uneven settlement occurs after the base plate is soaked, which accelerates the failure of rubber waterstop of some expansion joints, leading to intermittent water leakage.
Technical essentials for leakage stoppage maintenance and repair of expansion joints of underground utility tunnel structures:
1. Surface treatment: according to the location of the crack, the surface of the crack can be coated, bonded, inlaid and sprayed with cement mortar, waterproof quick setting mortar and epoxy mortar;
2. Internal treatment: for shallow joints and cracks that only need seepage prevention and plugging, cement grouting can be generally used. For cracks with an opening less than 0.3 or with a large seepage velocity and affected by temperature changes, chemical grouting should be used;
3. Structural treatment combined with surface treatment: for cracks that affect the integrity of the building or damage the structural strength, in addition to internal treatment, some still need to take structural treatment combined with surface treatment measures to meet the requirements of seepage prevention, structural reinforcement or restoration of integrity;
4. Treatment of surrounding seepage: find out the geological conditions and seepage positions on both sides of the building, and take corresponding measures to deal with them. The treatment methods include excavation and backfilling, drilling and grouting, and deepening the tooth wall.
