What is a caisson, what is the meaning of a caisson, what is the meaning of a caisson

Open caisson. The code definition is a structure in which soil is taken from the inside of the well after the surface is fabricated, and the well is lowered to a predetermined elevation.

Generally, when the depth of the underground pool or pump room is deep and the construction of large excavation is difficult, caisson construction is adopted.

Buy this specification and take a look, the specification number is CECS137:2002

It's a way to push someone into a well and kill them.

In addition, it is also an engineering term.

A device for collecting sewage, built on the foundation pit, sinking to a certain elevation with a long-arm excavator, and then connecting it with a pipe jacking pipe, doing a good job of launder, covering the lid can be, the cover is generally cast-in-situ, the compactness is good, and the prefabrication period is short.

Caisson foundation is a type of underground structure and deep foundation constructed by caisson method. It is to make a well-barrel-like structure (caisson) on the surface of the ground, and then under the enclosure of the well wall, through continuous excavation from the well, the caisson gradually sinks under the action of its own weight, and after reaching the predetermined design elevation, the bottom is sealed to construct the internal structure.

It is widely used in the foundation of bridges, chimneys and water towers; Pump rooms, underground oil depots, pool shafts and other deep well structures and shield or pipe jacking working wells.

Technically it is more stable and reliable, the amount of excavation is less, the impact on the adjacent buildings is relatively small, the caisson foundation is deeply embedded, the stability is good, and it can support a larger load.

A well without water can also be called a dry well.

The main structure of the caisson includes: well wall, cutting edge, partition wall, groove, bottom seal, and top cover.

Shaft wall: The outer wall of the caisson is the main part of the caisson, which should have sufficient strength to withstand the load during the sinking process and during the use of the caisson; At the same time, it is also required to have enough weight so that the caisson can sink smoothly under its own weight.

Cutting edge: The lower end of the shaft wall is generally made into a blade-shaped "cutting edge", and its function is to reduce the sinking resistance.

Partition wall: arranged in the caisson wellbore, its main function is to increase the stiffness of the caisson in the sinking process, and at the same time, the whole caisson is separated into a plurality of construction wells (taking soil wells), so that the excavation and sinking can be carried out more evenly, and it is also convenient for the deviation correction when the caisson is deflected.

Groove: Arranged on the inside of the wall above the cutting edge, its function is to make the bottom concrete and the bottom plate and the wall have a better connection to transmit the base reaction force.

Bottom sealing: When the caisson sinks to the design elevation, after technical inspection and the bottom of the well is cleaned and leveled, the bottom can be sealed to prevent groundwater from seeping into the well.

Top cover: the top of the well is poured with reinforced concrete top cover, and the top cover can be built only after the top cover reaches the design strength.

Open caisson.

It is a well-barrel-shaped structure, which is excavated in the well, relying on its own gravity to overcome the friction resistance of the well wall and then sinking to the design elevation, and then passing through the concrete bottom and filling the well hole, making it the foundation of the bridge pier or other structures. It is generally used in the construction of foundation pits of large bridge piers, sewage pumping stations, large-scale equipment foundations, civil air defense shelters, shield assembly shafts, underground lanes and station hydraulic foundation construction enclosure devices

Features of caisson foundations:

Advantages The embedding depth can be very large, the integrity is strong, the stability is good, there is a large bearing area, and it can bear large vertical and horizontal loads; The caisson is not only the foundation, but also the retaining and water-retaining structure during construction, and there is no need to set up pit wall support or sheet pile wall in the sinking process, which simplifies the construction; The caisson has little impact on adjacent buildings during construction.

Disadvantages: Long construction period;

High construction technical requirements;

Quicksand is prone to occur during construction, resulting in caisson tilting or sinking difficulties.

According to its cross-sectional contour, caissons are divided into three categories: circular, rectangular and round-ended. The flow resistance of the circular caisson is small, and compared with other types in the same area, the circumference is the smallest, and the frictional resistance is reduced accordingly, which is convenient for sinking; The borehole is only subject to axial pressure, and there is no problem of deviation around the axis. Compared with the circular caisson of the same area, the moment of inertia and core radius of the rectangular caisson are larger, which is beneficial to the base force. Under the action of side pressure, the outer wall of the caisson is subjected to greater flexural stress.

The round-end caisson has good adaptability to the supporting building, and can also make full use of the masonry of the foundation, and the stress of the shaft wall is also improved compared with the rectangular, but the construction is more complicated.

The textbook of a first-class municipal professional builder says that caissons are generally composed of the following parts.

a.Borehole wall bCutting edge cGroove.

d.The bottom beam is composed of e-partition walls and other parts.

Open caisson. It is the foundation of bridge piers or other structures.

The caisson is a wellbore-shaped structure, which is excavated in the well, relying on its own gravity to overcome the frictional resistance of the well wall and then sinking to the design elevation, and then passing through the concrete bottom and filling the well hole, making it the foundation of the bridge pier or other structures. Generally, in the construction of large bridge piers foundation pits, sewage pumping stations, large equipment foundations, civil air defense shelters, shields.

It is used in the construction of enclosure devices for assembling wells, underground lanes and station hydraulic foundations.

Advantages of caissons.

1. The embedding depth can be very large, with strong integrity, good stability, large bearing area, and can bear large vertical and horizontal loads.

2. The caisson is not only the foundation, but also the retaining and water-retaining structure during construction, and there is no need to set up pit wall support or sheet pile wall during the sinking process, which simplifies the construction.

3. The caisson construction has little impact on the adjacent buildings.

Disadvantages of caissons.

1. The construction period is long.

2. High construction technical requirements.

3. Quicksand is prone to occur during construction, causing caisson tilting or sinking difficulties.

What is the difference between a working well and a caisson A working well is a caisson with pipe jacking equipment installed and jacked; The receiving well is the well from which the pipe on top leads through. The caisson is a construction method, that is, at the wellhead position, the caisson blade foot and a section of the well wall are prefabricated, sinking while digging, and then pouring on the ground, connecting the long well wall, and continuing to sink. This method began to be mostly used in water conservancy projects, the process is simple, usually using brick well wall, manual excavation, self-weight sinking.

The term caisson is explained as: a well-barreled underground structure. First, build a section (or all) of the well on the ground, dig out the soil in the well, and let it sink gradually.

After that, the well body is lengthened section by section until it sinks to a predetermined depth. It can be used as an underground pump house and pool, or filled with concrete, as the foundation of large bridges and heavy buildings.

The term caisson is explained as: a well-barreled underground structure. First, build a section (or all) of the well on the ground, dig out the soil in the well, and let it sink gradually.

After that, the well body is lengthened section by section until it sinks to a predetermined depth. It can be used as an underground pump house and pool, or filled with concrete, as the foundation of large bridges and heavy buildings. The structure is:

Shen (left and right structure) wells (single structure). Pinyin is: chénjǐng.

What is the specific explanation of caisson, we will introduce it to you through the following aspects:

Verses about caissons.

If the text is not reported, it is like a caisson and a pepper mud sunken well and a saprolite sink at the bottom of a well.

Idioms about caissons.

Dizzy and dazed, the night is drowsy, and the dusk is well-organized.

Words about caissons.

Avoid wells. Sentence formation about Hengshan staring at the caisson.

1. The flow regime and flow velocity changes in the caisson sinking process during the pier construction period were carried out through the indoor sink test.

2. Caisson technology is a commonly used method in deep foundation construction.

3. The article introduces the construction method of steel plate caisson and the measurement control and deviation correction measures in the process of pipe jacking.

4. In this paper, the sinking process of caisson is analyzed by physical and mechanical methods, and the analysis theory and construction method of the process are proposed, which have been verified in practice.

5. It is mainly used to measure the diameter and wellbore deflection of pile foundation boreholes, and can also be used for curtain and caisson wellbore measurement, as well as downhole cavity measurement for coastal engineering and salt water dissolution mining.