Author:Site Editor Publish Time: 2021-02-04 Origin:Site
Manholes are generally used in passable or semi-passable tunnels and channels for laying cables or pipelines. When various pipes enter the building through tunnels or semi-passable channels, manholes should be provided in the entry area. It is used a lot in municipal administration, and there are channels for various cables and pipes. Manholes are used for overhauling, threading, or extending cables as cable heads. Manholes should be set at cable turns and joints. In some cases, a manhole well is set up at a distance, and the well is connected by concrete pipes, and cables are laid in it.
People can go down the manhole for inspection and maintenance. Under the common manhole cover is a manhole, a vertical passage from the ground to the underground. The sewer system and underground piping of the underground cable room are constructed. These underground facilities need regular maintenance, inspection and cleaning. People use manholes to access underground pipe systems and other parts. The manhole can be used to connect pipeline equipment to facilitate the cleaning, inspection, and maintenance of underground passages.
Manholes are designed with manhole covers, which can be opened. There are holes on the wall of the manhole to connect pipeline equipment. The earliest manholes were made of brick and concrete, and they are now very common. With the progress of the times, the safety and functionality of manholes are constantly improving. Plastic manholes and glass fiber reinforced manholes are also being used more and more. Manholes made of these composite reinforced materials have better anti-corrosion and anti-seepage performance and are easier to handle and assemble on site.
According to the material classification, it is mainly divided into two categories: non-brick concrete manhole and brick concrete manhole.
Brick concrete manholes include reinforced concrete manholes, cement prefabricated manholes, brick cement manholes, etc.
Non-brick concrete manholes include plastic manholes and glass fiber reinforced manholes.
At present, it is very time-consuming and labor-intensive to use concrete for manholes. Traditional manholes built with cement or other commonly used materials are no longer reasonable and outdated. They have many disadvantages.
According to the purpose of classification, it is divided into three categories: shallow manholes, normal manholes and deep manholes.
Shallow Manholes are mainly installed at the branch of the sewer where there is not much traffic.
Normal Manholes: The most common manholes, usually located in the pipelines of sewers and underground pipes. Cover the manhole cover, usually rectangular or square.
Deep Manholes: The depth is deep, and there are generally ladders inside, with heavy manhole covers.
Assemble the manhole and disassemble it into parts during transportation. Greatly save the space and cost of transportation and loading. The manhole does not need to be lifted by large machinery, and there is no risk of breaking or falling.
Composite manhole chamber is very light, generally only one-tenth the weight of concrete. Easy to transport and install. Installation and construction personnel will not cause dangerous accidents due to the weight of the manhole. The production uses less materials and is more environmentally friendly.
Composite manholes have lower maintenance costs, smooth surfaces, and easier flushing of prefabricated manholes.
It is more resistant and stable to various chemicals caused by sewage or soil. Non-conductive, anti-corrosion, stronger toughness.
The sealing is better, and the facilities in the manhole room are more protective.
The prefabricated composite manhole requires accessories such as ladders, which can be set in advance, without adding other accessories after the manhole and manhole cover are installed.
Traditional brick manholes will have a large use site, remaining residual bricks, and difficulty in disposing of cement waste during the construction process. This has a serious impact on the environment. Brick manholes must be laid before optical cables or cables, which will cause poor positioning of manholes. Accuracy makes the fiber optic cable tray inaccurate and the loss increases. Traditional manholes need mortar covers, and the mortar covers need to be reused during maintenance, which requires long maintenance time and a heavy workload.
The practice has proved that composite manholes are lighter than traditional manholes, are easy to transport, have strong toughness, strong bearing capacity, and have high adaptability. In the construction of communication pipelines, organic composite manholes greatly simplify the construction steps and eliminate the need for bricks. The construction process and space measurement are difficult, and the construction difficulty is high, which greatly saves construction costs, effectively reduces the impact of construction waste on the environment, and also saves time and costs to ensure that the optical cable construction and manhole construction are carried out simultaneously. The composite manhole well solves the problems of water leakage and non-freezing and high-temperature resistance of the brick manhole well.
If it is a traditional pouring manhole, the amount of concrete must be calculated in advance before pouring. Prepare the material for pouring. Dig the reserved pit, and traditional pouring requires a pit several times the size of the composite manhole. During excavation, the mainline of the manhole seat should be on the same axis as the pipeline in the trench. In this regard, the pouring method is time-consuming and laborious. After digging the hole, use the model to pour it. After it is dry, remove the template. Some connecting holes need professional tools to drill and polish.
Pouring manholes need to be kept dry after pouring, and must be kept clean after pouring. Before drying and hardening, prevent any sewage and rain from entering. It is necessary to cut or reserve holes before installing cables and other pipes.
The installation of additional joints should be based on the size of the wellbore and the diameter of the connecting pipeline, using special tools to make holes on the manhole wall, and the circumference of the hole should be flat. Finally, connect the pipeline and lay the upper manhole cover. The steps are cumbersome and take a long time.
If it is a brick manhole, many raw materials such as bricks, sand and cement are needed. It also requires more manpower. It takes a long time to build manholes, and the positions of reserved holes and pipe connections also require more technology and operation time. The installation of the manhole circle also requires large-scale mechanical lifting. After the manhole ring is installed, the outer ring of the manhole needs to be poured to reinforce it to prevent leakage in the gap.
After everything is done, backfill the soil. Traditional pouring, brickwork, or concrete manhole installation is completed.
After assembling the composite manhole, digging a hole of the corresponding size directly, it can be assembled and installed. The material is light, the combination is simple, and there is no need for operations such as pouring and cutting. It saves many tedious steps and provides a faster and safer manhole installation program for construction.
Excavation of manhole foundation pit. Accurately stake out the vertical and horizontal axis of the manhole position, and determine the edge of the manhole according to the position of the vertical and horizontal axis to determine the excavation range.
Excavate the manhole according to the sideline of the manhole. The slope of the excavation side slope should be smooth, and after leveling, use a small rammer to compact the base.
Place the assembled manhole, install the manhole well on the brick manhole base according to the design of the drawing, and pour the curb with concrete to fix the manhole well on the well base. Then install the pipes at the connection. Finally, backfill the soil and install the manhole cover.
Most of the underground communication wells used in communication projects are made of bricks. This requires construction personnel to use bricks and cement on site. Therefore, it takes a long time from the communication well to the actual construction of cables. Valuable manpower and material resources are also wasted. In addition, due to the long-term underground, the communication well built with bricks is very likely to be damaged or collapsed, so the later inspection personnel cannot repair the cables.
Jinmeng inspection manhole chambers realize preset modular communication manholes, including floor, manhole body, manhole cover and bolts, and other accessories required for assembly. Jinmeng inspection manhole chambers support customization.
The preset communication manhole well of the utility model has fast on-site installation and construction speed, simple construction, small road surface destruction, and low maintenance difficulty and cost in the later period; in addition, when the reserved through-hole of the joint is connected through a pipe plug and is connected without a pipe For blocking purposes.
Before installing the manhole chamber, digging a pit needs to survey the site, and the foundation soil must not be disturbed. If the groundwater level is higher, a precipitation level treatment measure is required.
The installation depth should be calculated in advance, and the manhole should be installed vertically. When installing the pipe connection, do not use a heavy hammer to hit, and should use professional tools.
The installation sequence of the manhole must be strictly followed.
Silt, garbage, frozen soil, etc. shall not be used for backfilling, and stones, bricks and other hard objects with edges and corners shall not be mixed. Backfilling should be manually layered and symmetrical backfilling, mechanical backfilling is strictly prohibited, its density is consistent with the pipeline backfilling, and the shaft must not be displaced or tilted.