Foundation pit lowering and drainage measures, six commonly used foundation pit dewatering methods

The six commonly used foundation pit precipitation methods are as follows:

1. Open ditch plus water collection well precipitation.

The open ditch plus the precipitation of the water collection well is a kind of artificial drainage method. It mainly excludes underground diving, construction water and rainfall from the ground. In the area where the groundwater is abundant, if only this method is used for precipitation, the construction of anchor spray net support is more difficult due to the more water seepage on the foundation pit slope.

Therefore, this precipitation method is generally not applied alone to foundation pit slope support in high water level areas.

2. Light well precipitation.

Light well point precipitation is suitable for occasions where the foundation pit area is not large and the water level is not deep. The method reduces the depth of the water level generally between 3 6 meters, if the precipitation depth is required to be greater than 6 meters, the multi-stage well point system can theoretically be adopted, but it is required that enough space is required outside the foundation pit to facilitate grading or trenching.

3. Precipitation at the injection well point.

The injection well point system can produce a vacuum of 250 mm mercury column at the bottom of the well point, and its depth of water level reduction is large, generally in the range of 8 20 meters. It is applicable to the same soil permeability coefficient as light well points, generally meters per day. However, its pumping system and jet well pipe are very complex, the operation failure rate is high, and the energy loss is large, and the cost is higher than that of other well point methods.

4. Electroosmosis well branches are stuffy and search for precipitation.

Electroosmotic well points are suitable for fine-grained soils with very small permeability coefficients, such as clay, sub-clay, silt and silty clay. The permeability coefficient of these soils is less than the daily meter, and it needs to be applied in combination with light wells or jet wells, and the depth of their water level reduction is determined by the light wells or jet wells.

5. Precipitation at tube well points.

Tube well points are suitable for formations with large permeability coefficients, formations with abundant groundwater, and occasions where light wells are not easy to solve. The effluent flow rate of each tube well can reach 50 100 cubic meters per hour, and the permeability coefficient of the soil is in the range of 20-200 meters per day, which is generally used for precipitation in the subsescent layer.

6. Precipitation at deep wells.

Deep well point precipitation is a more widely used precipitation method in foundation pit support, and its advantages are large drainage, large precipitation depth, and large precipitation range. For the occasion where the permeability coefficient of the gravel layer is large and the thickness of the permeable layer is large, the methods such as light well points and injection well points are generally ineffective, and this method is the most suitable to cover the world.

Hello dear, I'm glad that Sun Yi answered for you. How should the foundation pit drainage be used, 1. Open ditch drainage: The so-called open ditch drainage is to collect the groundwater flowing into the trench or foundation pit into the collection well, and then pump it away.

When excavating a trench or foundation pit with a low foundation or a small amount of water, the method of open ditch drainage is usually adopted. The groundwater seeping out from the pit wall and pit bottom is collected into the Kaixin well through the drainage ditch and discharged out of the pit by the pump. 2. Seepage and drainage

The so-called seepage drainage is to concentrate the water seeping out of the water layer into the collection well through a scattered pipe, and then use a pump or other machinery to drain the water. According to the size of the drainage, the water collection pipe of seepage drainage can be selected with sand-concrete pipe or hard plastic pipe. The design slope of the scattered pipe for seepage drainage is generally not more than 1%, and the spacing is 5 10m for laughing wheels.

3. Blind ditch drainage: Blind ditch is generally located around buildings or structures, and is composed of sand and pebbles. The blind ditch and the excavation of the foundation pit should be combined as much as possible.

The spacing of the blind ditch should be determined according to the engineering geological conditions. 4. Collecting well precipitation: it is gravity precipitation, generally digging drainage ditches around the bottom of the pit, and setting up collection wells at certain intervals, and then discharging the foundation pit with a pump.

5. Well point precipitation method: there are light well points, jet well points, electroosmosis well points, tube well method and deep well pump method. Hope mine is helpful to you!

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When it comes to foundation pit dewatering measures, relevant construction people are still relatively unfamiliar, a reasonable foundation pit excavation process, how to deal with foundation pit dewatering? What are the main measures? The following is the basic content of foundation pit excavation for builders by Zhongda Consulting, the specific content is as follows:

Foundation pit support is to ensure the safety of the underground structure construction and the surrounding environment of the foundation pit, the side wall of the foundation pit and the surrounding environment of the use of support, reinforcement and protection measures.

Through the combing of relevant content, what are the commonly used foundation pit dewatering measures for the smooth progress of various foundation pit excavation projects of construction enterprises? Through the collation of relevant contents, the main contents are as follows:

1) Quality standards.

The body of the precipitation well should be round and vertical;

The diameter of the well bore should be at or greater than the design diameter;

The deviation between the actual well depth and the well depth should be less than 50cm;

The deflection of the apex angle shall not exceed h%;

When the well pipe is lowered, it should be upright in the center of the well, and its deflection should be less than h%.

2) Control measures.

When the construction of the precipitation well encounters an underground obstacle, the obstacle is manually removed, and the hole construction is carried out after the casing is lengthened;

After the installation of the well pipe is completed, the filter material should be filled evenly and continuously along the perimeter of the well pipe in time, and when it is found that there is a large difference between the filling amount and the depth and the calculation, the reason should be found out and discharged;

After the well is filled with filter material to close the periphery, the well should be washed with compressed air in time;

After the well is washed, the pumping test should be carried out, and the water output should not be less than the design water output of the tube well. Let the state sparrow.

Hello, I have helped you find the result; When carrying out foundation pit drainage, the following precautionary measures can be taken to ensure construction safety and effective drainage:1Well-designed drainage system:

When designing foundation pits, a reasonable drainage system should be considered, including drainage pipes, drainage wells and other facilities. Ensure that the drainage system can effectively remove the stagnant water in the foundation pit. 2.

Clean drainage facilities regularly: Clean drainage pipes and drainage wells regularly to prevent blockages and water accumulation. 3.

Install a drainage pump: If the water in the foundation pit cannot be removed by natural drainage, you can consider installing a drainage pump to improve drainage efficiency. 4.

Strengthen foundation pit waterproofing: Before the construction of the foundation pit, the foundation pit waterproofing treatment can be carried out, and waterproof materials or construction technology can be used to prevent groundwater from seeping into the foundation pit. 5.

Regularly inspect the ground around the foundation pit: regularly check whether the ground around the foundation pit is sinking or deformed, and take timely measures to repair it to prevent the ground around the foundation pit from collapsing. 6.

Do a good job in on-site management: strengthen the management of the current cover pants yard to ensure that the construction personnel operate in accordance with the specifications, abide by the safety operation procedures, and improve the construction safety. The above is all my reply, I hope to be able to help you, I wish you a happy life <>

The method of foundation pit precipitation, the relevant construction people are still relatively unfamiliar, what are the calculation methods of foundation pit precipitation? The following is the basic information of the method of foundation pit dewatering for construction professionals, which is as follows:

The methods of foundation pit precipitation mainly include: water collection and open drainage, light well points, jet well points, electroosmosis well points and other foundation pit precipitation methods, in which the content of decompression precipitation is as follows:

The purpose of decompression and precipitation: to reduce the confined water head height of the lower confined aquifer in time to prevent the occurrence of sudden surge at the bottom of the foundation pit and ensure the stability of the foundation pit floor during construction.

a) The confined aquifer in the pit is semi-closed.

b) Suspended waterproof curtains.

c) The confined aquifer in the pit is fully enclosed.

Schematic diagram of decompression and precipitation structure outside the pit.

The precipitation operation control method is briefly described as follows:

1) The principle of "decompression and precipitation on demand" should be strictly observed, and the relationship between environmental factors, the buried depth of the safe confined water level and the construction conditions of the foundation pit should be comprehensively considered, and the phased confined water level control standards of each construction section should be determined, and a detailed decompression and dewatering operation plan should be formulated.

2) In the process of precipitation operation, the decompression precipitation operation plan should be strictly implemented. If the foundation pit construction conditions change, the precipitation operation plan should be adjusted or modified in time.

3) The water pumped out of all pressure reduction wells should be discharged into natural water bodies outside or near the influence area of the foundation pit. The on-site drainage capacity should take into account the amount of water discharged from all pressure relief wells (including backup wells) when the Quanjing Silver Department is in operation. The water pump outlet of each pressure reducing well should be equipped with a water quantity metering device and a check valve.

4) After the construction of the pressure reducing well is completed and the on-site drainage system is installed, a group well pumping test or pressure reduction precipitation test should be carried out, and a comprehensive inspection should be carried out on the power system (including backup power supply), drainage system, well pumping pump, measurement system, automatic monitoring system, etc.

5) The operation of precipitation should be monitored continuously without interruption. For major deep foundation pit projects, the automatic water level monitoring system should be considered to track and monitor the confined water level throughout the whole process, so that the changes in the confined water level inside and outside the foundation pit during the precipitation operation process can be monitored at any time.

6) The environmental background value should be measured within 1 week before the official start of precipitation operation, and the monitoring content includes the initial confined water level inside and outside the foundation pit, the initial value of the adjacent ground settlement around the foundation pit, the initial deformation of the protection object and the deformation of the foundation pit enclosure and the collapse body, etc., and the monitoring project that repeats the design requirements of the foundation pit can use the foundation pit monitoring data. In the process of precipitation operation, the data of the supervision and lighting should be sorted out in time, the relevant curves should be drawn, and the problems that may occur should be dealt with in a timely manner.

7) When the environmental conditions are complex and the surface settlement of the foundation pit caused by precipitation is greater than the environmental control standard, the precipitation amplitude, artificial groundwater recharge or other effective environmental protection measures can be taken.

8) After the precipitation is stopped, reliable sealing measures should be taken for the precipitation tube well.