In housing and municipal facilities, underground pipe trenches are usually cast on-site or constructed with masonry. Cast-on-site or masonry construction uses wet work, which depends on the workers' operating level. The construction quality is not easy to guarantee, and it is easy to crack and leak, and rework processing occurs from time to time. The industrialization level is low, and it is easy to cause material waste during the construction process, and the construction period is long, which does not conform to the current development concept of energy conservation and environmental protection.
Precast concrete trenches can be mass-produced according to design specifications, prefabricated in the factory, and installed on-site. Sockets and waterproof mortar connect the prefabricated pipe trench segments to ensure the integrity and waterproof effect of the pipe trench. The flatness, verticality, and appearance quality of the prefabricated components are good, and no secondary plastering is required, which avoids material waste. Prefabricated pipe trench construction can realize industrialized production and mechanized installation, with convenient construction and a high degree of mechanization. It has the advantages of good quality, fast progress, energy saving and environmental protection, and industrialized construction.
Technical Features
1. Precast concrete trenches are composed of U-shaped prefabricated trench segments and prefabricated trench covers. The prefabricated trench segments are connected to form a trench as a whole. Water, electricity, heating, and other pipelines are laid in the prefabricated trench.
2. Precast concrete trenches are processed by fixed length, which can realize factory mass production, with good molding quality, and can achieve the effect of plain concrete, fully meeting the functional requirements.
3. Precast concrete trenches are light in weight and easy to hoist and install as a whole. The precast trench segments are connected by sockets and waterproofed, and the integrity and waterproofing effect of the trench are good.
4. Precast concrete trenches cancel wet construction, avoid plastering, save labor, speed up progress, save energy, and protect the environment.
5. Precast concrete trenches adopt reinforced concrete structure, good durability, and prefabricated component assembly construction, which is easy to maintain.
Operation Steps
Precast concrete trenches location confirmation → Precast trench drawing deepening design → Precast trench production and transportation → Precast trench trench excavation → Precast trench bottom cushion construction → Precast trench hoisting → Precast trench installation → Pipeline laying in trench → Trench cover installation
Precast Trench Location Confirmation
According to the engineering drawings, confirm the construction location and the size of the precast trench. At the same time, the installation error needs to be considered. The length of the precast trench is reduced by 10mm at each end.
According to the lifting capacity of the lifting equipment, determine the size of the precast trench segment to ensure that the weight of the precast component is within the lifting capacity of the lifting equipment.
During the drawing deepening process, it is necessary to consider the lifting, transportation, installation, reinforcement, and other links, set the necessary embedded parts and reserved holes, and carry out the drawing deepening design of the pipeline bracket embedded parts.
Installation Of Precast Concrete Trenches
Use theodolite and level to determine the installation position and elevation of the trench, and then stake out on site. Sprinkle lime lines on both sides of the trench, determine the installation position of the prefabricated trench, and use an excavator to dig the trench.
Construction Of The Bottom Cushion Of The Precast Concrete Trenches
After the installation position of the prefabricated trench is determined, a C15 concrete cushion is poured on the base. The thickness of the cushion is not less than 100mm, and the width of the cushion should be greater than the width of the trench, not less than 300mm on each side.
Precast Concrete Trenches installation
Check whether the lower elevation of the prefabricated pipe trench meets the installation requirements. If not, leveling is required. Prepare the hoisting tools and equipment required for the prefabricated pipe trench.
The prefabricated pipe trench is hoisted to the designated location by special hoists and slings, and then the temporary fixing components are installed. After the temporary fixing components are installed, the crane is unhooked and the prefabricated pipe trench segment is installed in place with the help of measuring instruments.
After the installation of a prefabricated pipe trench segment is completed, the next prefabricated pipe trench segment is installed one by one. The two adjacent prefabricated pipe trench segments are connected by a socket to form a whole, and waterproof mortar is used at the socket position for waterproofing.
Laying Of Pipelines In Trenches
After the trenches are installed, the debris in the trenches is cleaned up. After inspection and acceptance by all parties, pipelines in the trenches are laid. The order of laying pipelines is first the lower part and then the upper part.
Installation Of Trench Cover
After the pipelines in the trench are laid, the trench cover is installed. The trench cover and the trench segment are prefabricated at the same time. The two ends of the trench cover are placed on the top of the prefabricated trench segment. After the cover is hoisted in place, the gap between the two adjacent covers is sealed with waterproof mortar. After the trench cover is installed, the two sides of the trench are filled with backfill soil.
Benefit
Construction period benefit
The prefabricated trench is prefabricated in the factory and directly installed after being transported to the site. After being hoisted to the designated location, the prefabricated trench segments are connected by sockets and waterproofed. Compared with on-site cast-in-place and masonry construction, the construction speed of prefabricated trench construction is fast and can save 1/2 of the working hours.
Economic benefit
The cost of the cast-in-place structure (taking a 2m width as an example) ditch is about 1,800 yuan/cubic meter, and the cost of using a prefabricated trench is about 2,600 yuan/cubic meter. The cost of a prefabricated trench is 800 yuan/cubic meter higher than that of a cast-in-place structure. Due to the small sample volume, the amortization cost of prefabricated trench mold is relatively large, and the cost gap tends to gradually decrease with the increase in usage.
Social benefits
Prefabricated trench adopts industrialized products, with good flatness and verticality, no hollowing and cracking, and good construction quality. Waterproof mortar is used between each prefabricated segment for waterproof treatment, and the waterproof effect is good.
The fixed-length processing of prefabricated trenches can realize industrialized production and mechanized installation, with simple procedures and high construction efficiency. Finished components do not require wet operations such as plastering, less pollution, energy saving, and environmental protection.
Compared with cast-in-place structure and masonry construction, prefabricated trench construction has obvious advantages in terms of construction period, quality, and environmental protection.
