Foundation pit drainage system and construction method

Abstract

The invention relates to the field of foundation pit drainage, and discloses a foundation pit drainage system and a construction method.The foundation pit drainage system comprises a drainage ditch, a water collecting pit, a dewatering well, a drainage ditch and water pumping equipment, the drainage ditch is located around a foundation pit, the water collecting pit is located at the corner of the foundation pit, the drainage ditch is communicated with the water collecting pit, and the drainage ditch and the water collecting pit are filled with pebbles; the dewatering well is arranged at the lowest position in the foundation pit, a plurality of drainage ditches extend on the dewatering well, a circle of backfilling layer is arranged on the well wall of the dewatering well and extends to the drainage ditches, a sealing steel plate is installed at the well mouth of the dewatering well, and the water pumping equipment is installed in the dewatering well. A water outlet of the pumping equipment is connected with the drainage ditch. Waterproof treatment is carried out on the surface of the foundation pit, the drainage ditch and the water collecting pit are machined for collecting surface water, the dewatering well is machined for collecting underground seepage water, and normal operation of a drainage system of the foundation pit is guaranteed.

Description

Technical Field

[0001] The invention relates to the field of foundation pit drainage, and in particular to a foundation pit drainage system and a construction method. Background Art

[0002] The foundation pit is a soil pit excavated at the foundation design location according to the base elevation and foundation plane size. It is the foundation of underground foundation construction. The foundation pit is divided into shallow pits and deep pits according to the depth. Deep pits are mostly built to adapt to the depth of the underground foundation. In order to ensure that the foundation pit can be constructed under dry conditions and prevent the occurrence of slope instability, foundation sand flow, pit bottom uplift, pit bottom pipe burst and foundation bearing capacity reduction, the foundation pit needs to be constructed after the foundation pit is dug. The existing method is to dig drainage ditches and water collection wells in the foundation pit, and then connect the drainage ditch to the water collection well, and install pumping equipment in the water collection well to pump out the accumulated water. However, this situation is suitable for areas with less rain. When encountering rainwater-rich areas, drainage ditches and water collection wells are difficult to be removed in time. For a long time, the groundwater level will surge, causing slope instability, pit bottom pipe burst, foundation bearing capacity reduction, etc., and rainwater will carry a lot of sediment to the drainage ditch and water collection well, causing the pumping equipment to be blocked. In addition, the rise in groundwater level will also affect the drainage effect of the foundation pit, and ultimately affect the underground foundation construction. Therefore, a drainage system is needed that can quickly discharge the accumulated water in the foundation pit and avoid blockage. Summary of the invention

[0003] The purpose of the present invention is to solve the problems in the background technology and provide a foundation pit drainage system and a construction method.

[0004] The objective of the present invention is achieved through the following technical solutions:

[0005] A foundation pit drainage system comprises a drainage ditch, a sump, a drainage well, a drainage ditch and a pumping device, wherein the drainage ditch is located around the foundation pit, the sump is located at a corner of the foundation pit, the drainage ditch is connected to the sump, the drainage ditch and the sump are filled with pebbles, the pebbles are covered with a geotextile, the drainage well is arranged at the lowest point in the foundation pit, a plurality of drainage ditches extend from the drainage well, a circle of backfill layer is arranged on the wall of the drainage well, the backfill layer extends to the drainage ditch, a sealing steel plate is installed at the wellhead of the drainage well, the pumping device is installed in the drainage well, and the water outlet of the pumping device is connected to the drainage ditch.

[0006] A construction method for a foundation pit drainage system comprises the following steps:

[0007] (1) Excavate a foundation pit on the ground according to the design, and excavate drainage ditches and sump pits around the foundation pit. When excavating the drainage ditch, find the slope towards the sump pit;

[0008] (2) Use a sewage pump to pump water out of the sump to ensure that there is no water in the sump and drainage ditch. Then bury the drainage pipe in the drainage ditch, and then pour cement mortar in the drainage ditch. After the cement mortar hardens, backfill the drainage ditch with pebbles;

[0009] (3) Install a branch pipe in the sump, connect the water inlet of the branch pipe to a check valve, then connect the branch pipe to a sewage pump, and connect the water outlet of the branch pipe to the main pipeline;

[0010] (4) Start trial operation. After it can operate normally, cover the pebble backfill area with geotextile and carry out waterproofing construction on sunny days to reduce rainwater penetration;

[0011] (5) A drainage well is drilled at the lowest point of the foundation pit, and a steel pipe is installed in the drainage well. Seepage holes are processed on the steel pipe. After the steel pipe is installed in place, the outside of the steel pipe is backfilled with rice stones to form a filter layer, and waterproofing construction is carried out around the drainage well. Then a submersible pump is installed at the bottom of the steel pipe;

[0012] (6) Install a sealing steel plate at the wellhead of the precipitation well and cut off the excess steel pipe. Then install a fire water pipe and connect it to the drainage pipe on the sealing steel plate. Use grease to seal the sealing steel plate and the precipitation well.

[0013] The main pipeline pumps water to the drainage ditch outside the foundation pit retaining wall.

[0014] The branch pipe is buried underground.

[0015] The foundation pit drainage system and construction method provided by the present invention have the following beneficial effects:

[0016] (1) Waterproof the surface of the foundation pit, construct drainage ditches and sump pits to collect surface water, and construct precipitation wells to collect underground seepage water, thus ensuring the normal operation of the foundation pit drainage system;

[0017] (2) Using a submersible pump to pump groundwater into a drainage pipe and then using a sewage pump to pump the water out can reduce the operating power of the submersible pump and increase its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of the structure provided by an embodiment of the present invention.

[0020] Figure 2A schematic diagram of the structure of a drainage ditch provided in an embodiment of the present invention.

[0021] Figure 3 for Figure 2 Enlarged view of point A in the middle.

[0022] Figure 4 A schematic structural diagram of a precipitation well provided in an embodiment of the present invention.

[0023] Figure numerals: 1. drainage ditch; 2. sump; 3. precipitation well; 4. drainage ditch; 5. pebbles; 6. geotextile; 7. drainage pipe; 8. branch pipe; 9. rice stone; 10. sealing steel plate. DETAILED DESCRIPTION

[0024] Example

[0025] like Figure 1 to Figure 4 As shown, a foundation pit drainage system provided in this embodiment includes a drainage ditch 1, a sump 2, a drainage well 3, a drainage ditch 4 and a pumping device, wherein the drainage ditch 1 is located around the foundation pit, the sump 2 is located at the corner of the foundation pit, the drainage ditch 1 is connected with the sump 2, the drainage ditch 1 and the sump 2 are filled with pebbles 5, and the pebbles 5 are covered with a geotextile 6, the drainage well 3 is arranged at the lowest point in the foundation pit, a plurality of drainage ditches 4 extend from the drainage well 3, a circle of backfill layer is provided on the wall of the drainage well 3, and the backfill layer extends to the drainage ditch 4, a sealing steel plate 10 is installed at the wellhead of the drainage well 3, the pumping device is installed in the drainage well 3, and the water outlet of the pumping device is connected with the drainage ditch 1.

[0026] A construction method for a foundation pit drainage system comprises the following steps:

[0027] (1) Excavate the foundation pit on the ground according to the design. After the foundation pit is excavated, dig drainage ditch 1 and sump 2 around the foundation pit. The drainage ditch 1 is 200×200㎜, and the sump 2 is 400×400×400㎜. When digging the drainage ditch 1, find the slope towards the sump 2;

[0028] (2) Using the excavated drainage ditch 1, the sewage pump is used to pump water in the sump 2 to ensure that there is no water accumulation in the sump 2 and the drainage ditch 1. According to the set position, the trench is excavated in advance, and then the drainage pipe 7 is buried in the drainage ditch 1. Then, cement mortar is poured in the drainage ditch 1. After the cement mortar hardens, pebbles 5 are backfilled into the drainage ditch 1. The backfilled pebbles 5 should be cleaned of mud and sand. The pebbles 5 have a particle size of 25 to 50 mm to prevent mud and sand from clogging the pipe;

[0029] (3) Install a branch pipe 8 in the sump 2. Before burying the branch pipe 8, use a sewage pump to pump out the accumulated water in the sump 2. The branch pipe 8 is buried underground. The water inlet of the branch pipe 8 is connected to a check valve to prevent the water in the pipe from flowing back. Then, connect the branch pipe 8 to the sewage pump, and connect the outlet end of the branch pipe 8 to the main pipe. The main pipe is used to pump water to the drainage ditch 1 outside the retaining wall of the foundation pit.

[0030] (4) After the branch pipe 8 is installed, the test run is started. After it can run normally, the backfill area of ​​the pebble 5 is covered with geotextile 6, and then the branch pipe 8 is plastered and filled with cement mortar with a ratio of 1:3 to make it smooth. The geotextile 6 is laid on the backfill area of ​​the pebble 5. At the same time, waterproofing construction is carried out on sunny days without water accumulation to reduce the downward penetration of rainwater;

[0031] (5) Drill a drainage well 3 at the lowest point of the foundation pit. The diameter of the drainage well 3 is 500 mm, and the hole depth is 3.1 m at the top elevation of the cushion layer. Then install a steel pipe in the drainage well 3. The steel pipe is φ320 and 3 m long. Seepage holes are processed on the steel pipe. After the steel pipe is installed in place, fill the filter layer with rice stone 9 on the outside of the steel pipe, and waterproof construction is carried out around the drainage well 3. Then install a submersible pump at the bottom of the steel pipe; then excavate the earthwork for the second time. Avoid touching the steel pipe during the excavation process, and then cut off the excess steel pipe;

[0032] (6) Cut off the excess steel pipe so that the top of the steel pipe is flush with the top of the cushion layer, install a sealing steel plate 10 at the wellhead of the precipitation well 3, and then install a fire water pipe on the sealing steel plate 10 to connect it to the drainage pipe 7. Use grease to seal the sealing steel plate 10 and the precipitation well 3.

[0033] The above is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any modification and replacement based on the technical solution and inventive concept provided by the present invention shall be included in the protection scope of the present invention. It should be noted that the structures or components illustrated in the drawings are not necessarily drawn to scale, and the present invention omits the description of known components and processing technologies and processes to avoid unnecessary limitation of the present invention.

Claims

1. A foundation pit drainage system, characterized in that: It includes drainage ditches, sump pits, precipitation wells, drainage ditches and pumping equipment. The drainage ditches are located around the foundation pit, the sump pits are located at the corners of the foundation pit, the drainage ditches are connected with the sump pits, the drainage ditches and the sump pits are filled with pebbles, the pebbles are covered with geotextiles, the precipitation wells are set at the lowest point in the foundation pit, a plurality of drainage ditches extend from the precipitation wells, a circle of backfill layer is provided on the wall of the precipitation wells, the backfill layer extends to the drainage ditch, a sealing steel plate is installed at the wellhead of the precipitation well, the pumping equipment is installed in the precipitation well, and the water outlet of the pumping equipment is connected with the drainage ditch.

2. A construction method for a foundation pit drainage system according to claim 1, characterized in that: The following steps are involved: (1) Excavate a foundation pit on the ground according to the design, and excavate drainage ditches and sump pits around the foundation pit. When excavating the drainage ditch, find the slope towards the sump pit; (2) Use a sewage pump to pump water out of the sump to ensure that there is no water in the sump and drainage ditch. Then bury the drainage pipe in the drainage ditch, and then pour cement mortar in the drainage ditch. After the cement mortar hardens, backfill the drainage ditch with pebbles; (3) Install a branch pipe in the sump, connect the water inlet of the branch pipe to a check valve, then connect the branch pipe to a sewage pump, and connect the water outlet of the branch pipe to the main pipeline; (4) Start trial operation. After it can operate normally, cover the pebble backfill area with geotextile and carry out waterproofing construction on sunny days to reduce rainwater penetration; (5) A drainage well is drilled at the lowest point of the foundation pit, and a steel pipe is installed in the drainage well. Seepage holes are processed on the steel pipe. After the steel pipe is installed in place, the outside of the steel pipe is backfilled with rice stones to form a filter layer, and waterproofing construction is carried out around the drainage well. Then a submersible pump is installed at the bottom of the steel pipe; (6) Install a sealing steel plate at the wellhead of the precipitation well and cut off the excess steel pipe. Then install a fire water pipe and connect it to the drainage pipe on the sealing steel plate. Use grease to seal the sealing steel plate and the precipitation well.

3. The construction method of the foundation pit drainage system according to claim 2, characterized in that: The main pipeline pumps water to the drainage ditch outside the foundation pit retaining wall.

4. The construction method of the foundation pit drainage system according to claim 2, characterized in that: The branch pipe is buried underground.

Images