CN111236284A - A method and structure for groundwater drainage at the bottom of a basement and surrounding areas - Google Patents

Abstract

The invention discloses a groundwater drainage method and structure at the bottom and surrounding areas of a basement. In the invention, vertical and horizontal intersecting drainage culverts are arranged around and at the bottom of the basement, and a water collection well is set at the intersection point to temporarily collect the water from the drainage culvert and then divert it. To the dewatering well located at the four corners of the basement exterior wall, the water in the dewatering well is pumped to the outdoor water storage sedimentation tank through the submersible pump in the dewatering well, and the precipitated water is reused as construction water. The invention effectively solves the problem of drainage during foundation pit construction, accelerates construction speed, converts construction waste water into reclaimed water for comprehensive utilization of water resources, saves water and reduces construction costs, reduces groundwater pressure, and avoids basement floor and basement. The leakage risk of the external wall ensures the quality of the project.

Description

A method and structure for groundwater drainage at the bottom of a basement and surrounding areas

technical field

The invention relates to a groundwater drainage method and structure at the bottom and surrounding areas of a basement, and belongs to the technical field of bridge engineering prefabricated component construction.

Background technique

With the rapid expansion of modern buildings, construction land is gradually lacking. The site selection of engineering projects is often complex and diverse, the depth of the foundation pit is deep, the area of the foundation pit is large, and there is still a large amount of groundwater and rainwater in the foundation pit. As a result, groundwater drainage is difficult during the construction of the foundation pit, and the construction progress is slow. After the building is put into use, there will be a large number of leakage points on the bottom plate and outer wall, and the later anti-seepage and plugging will be quite difficult. Using the existing technology for water drainage cannot ensure the orderly development of the construction surface during the construction process. When the groundwater level rises during the flood season, the groundwater will exert pressure on the floor, which will damage the basement infrastructure and cause leakage of the floor and outer walls. In addition, using the existing technology to discharge the water body in the foundation pit, especially the deep foundation pit, into the municipal sewage pipe network after treatment, the cost is high, the construction is difficult, and it is not conducive to the utilization of water resources. Therefore, the existing technology still has shortcomings and needs to be improved.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a groundwater drainage method and structure at the bottom of the basement and surrounding areas, so as to solve the problems such as the difficulty of groundwater drainage during the construction of the foundation pit, the excessive water pressure of the bottom plate and the outer wall of the basement, resulting in leakage and affecting the quality of the infrastructure. problems, thereby overcoming the deficiencies of the prior art.

To achieve the above object, the present invention adopts the following technical solutions:

The present invention provides a groundwater drainage method at the bottom of a basement and its surrounding areas. The method is to set up vertical and horizontal drainage underdrains around and at the bottom of the basement, and set up a collection well at the vertical and horizontal intersection points to temporarily collect the water from the drainage underdrain and lead it to the basement located in the basement. For the dewatering wells at the four corners of the outer wall, the water in the dewatering well is pumped to the water storage sedimentation tank on the outdoor ground through the submersible pump in the dewatering well, and the precipitated water is reused as construction water.

In the above-mentioned basement bottom and surrounding groundwater drainage method, the construction steps of the above method are as follows:

a. When excavating the basement foundation pit, excavate the foundation pit to less than 200mm below the bottom surface of the basement floor;

b. Continue to dig a deep pit 3m below the basement floor elevation at the four corners of the basement exterior wall, and then use reinforced concrete to pour a drainage well in the deep pit;

c. Compact the bottom of the foundation pit to form a plain soil compaction layer; pour a layer of 100mm thick concrete cushion on the top surface of the plain soil compaction layer;

d. Use gray bricks to build water collection wells on the concrete cushion, and the water collection wells are arranged in rows and columns on the concrete cushion of the basement floor to be poured and the outside of the basement exterior wall;

e. Lay the lower geotextile on the concrete cushion, and lay the anti-filter layer on the lower geotextile;

f. Install a drainage underdrain on the top surface of the reverse filter layer, and connect all the water collection wells and the dewatering wells located at the four corners of the basement exterior wall into one through the drainage underdrain to form a drainage grid;

g. Lay the upper layer of geotextile on the top surface of the reverse filter layer and the drainage ditch; backfill the cover soil layer on the top of the upper layer of geotextile to the elevation of the bottom surface of the basement floor and compact it;

h. Complete the concrete pouring construction of the basement floor and basement exterior wall on the top surface of the covering soil layer; backfill soil on the outside of the basement exterior wall to the outdoor ground level and compact it;

i. Build a water storage sedimentation tank on the side of the wellhead of the dewatering well; and install a floating ball valve and a submersible pump at the bottom of the dewatering well.

In the above-mentioned groundwater drainage method at the bottom of the basement and surrounding areas, the drainage ditch is laid with a finished ∩-shaped groove; the width of the lower opening of the ∩-shaped groove is 400mm and the height is 500mm; the bottom of the two side walls of the ∩-shaped groove is provided with a semicircular hole with a radius of 200 mm. as a water inlet.

In the above-mentioned groundwater drainage method at the bottom of the basement and surrounding areas, when the drainage underdrain is laid, the connection between each ∩-shaped groove and the catchment well or dewatering well shall be connected by M10.0 cement mortar; the drainage underdrain shall be kept at the middle height. The four corners are laid low to form a drainage slope of 0.5%.

In the above-mentioned groundwater drainage method at the bottom of the basement and surrounding areas, the reverse filter layer is composed of a pebble layer and a gravel layer; when the gravel layer is laid, the gravel layer forms an oblique triangle at the bottom of both sides of the drainage ditch; triangle The top height of the pile should cover the water inlet holes on both sides of the drainage culvert.

In the above-mentioned groundwater drainage method at the bottom of the basement and surrounding areas, when laying the upper layer of geotextile on the gravel layer and the top surface of the drainage culvert, the geotextile should be laid close to the top surface of the drainage culvert and the triangular pile.

In the above-mentioned groundwater drainage method at the bottom of the basement and surrounding areas, the pouring of the dewatering well adopts the staged pouring method, and the steel ladder is pre-buried on the well wall on one side of the dewatering well during pouring; the height of the first pouring is higher than the elevation of the basement floor to be poured; to be completed After the plain soil compaction layer, the concrete cushion layer, the water collecting well, the lower geotextile, the filter layer and the upper geotextile are constructed, the upper dewatering well shall be poured to the ground level.

A basement bottom and surrounding groundwater drainage structure of the present invention constituted by the above-mentioned basement bottom and surrounding groundwater drainage methods, including dewatering wells located at the four corners of the basement and a group of water collection wells located below the basement floor and outside the basement exterior wall; one The group collecting wells and the dewatering wells in the four corners of the basement are connected by drainage underdrains; the dewatering wells are provided with submersible pumps and floating ball valves, and the submersible pumps are located on the bottom of the dewatering wells; the submersible pumps are connected to the outdoor water storage sedimentation tank through the suction pipe .

In the groundwater drainage structure at the bottom of the basement and surrounding areas, the drainage underdrain is a connecting piece composed of a group of ∩-shaped grooves; the lower mouth of the ∩-shaped groove is 400mm wide and 500mm high; mm water inlet.

In the above-mentioned basement bottom and surrounding groundwater drainage structure, the upper layer of geotextile is arranged between the top of the drainage ditch and the bottom surface of the basement bottom in order from bottom to top, and the top surface of the upper layer of geotextile is provided with a covering soil layer; the bottom of the drainage ditch is from top to bottom. A gravel layer, a pebble layer, a concrete cushion layer and a plain soil compaction layer are arranged in sequence; wherein, the gravel layer is provided with a triangular pile on the outside of the drainage underdrain to cover the water inlet hole of the drainage underdrain.

Due to the adoption of the above technical solution, compared with the prior art, the present invention collects the groundwater and rainwater under the bottom plate and around the basement exterior wall into blocks and collects them into the dewatering well, and then the water body is pumped out of the outdoor water storage sedimentation tank through the dewatering well. In the process, the idea of "combining and comprehensive utilization of REDD" is effectively used. This solves the problem of drainage during foundation pit construction, speeds up construction, converts construction wastewater into reclaimed water for comprehensive utilization of water resources, saves water and reduces construction costs, reduces groundwater pressure, and avoids basement floor and basement exterior walls. Leakage risk ensures project quality.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Figure 2 is a cross-sectional front view of a blind drainage blind ditch;

Figure 3 is a schematic diagram of the structure of the ∩-shaped groove.

The markings in the figure are as follows: 1- Drainage underdrain, 2- Water collection well, 3- Dewatering well, 4- Water storage sedimentation tank, 5- Basement floor, 6- Basement exterior wall, 7- Outdoor floor, 8- Concrete cushion, 9 - Pebble layer, 10- Lower geotextile, 11- Plain soil compaction layer, 12- Overburden soil layer, 13- Submersible pump, 14- Float valve, 15- Pumping pipe, 16- Steel ladder, 17- Dewatering well cover, 18 - Well wall, 19- Dewatering well bottom plate, 20- Water inlet hole, 21- Upper geotextile, 22- Crushed stone layer, 23- Triangular accumulation.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

The present invention is a groundwater drainage method at the bottom of a basement and surrounding areas, as shown in Figures 1 to 3, the method is to set up vertical and horizontal drainage underdrains 1 around and at the bottom of the basement, and set up a collection well 2 at the vertical and horizontal intersection points. The water from the drainage ditch 1 is temporarily collected and then led to the precipitation wells 3 located at the four corners of the basement outer wall 6, and the water in the precipitation well 3 is pumped to the water storage sedimentation tank 4 of the outdoor ground 7 through the submersible pump 13 in the precipitation well 3. , the precipitation water is reused as construction water.

The construction steps of the above-mentioned groundwater drainage method at the bottom of the basement and surrounding areas are as follows:

a. When excavating the basement foundation pit, excavate the foundation pit to 200mm below the bottom surface of the basement floor 5;

b. Continue to dig a deep pit 3m below the basement floor 5 at the four corners of the basement outer wall 6, and then use reinforced concrete to pour the dewatering well 3 in the deep pit;

c. Compact the bottom of the foundation pit to form a plain soil compaction layer 11; pour a layer of 100mm thick concrete cushion 8 on the top surface of the plain soil compaction layer 11;

d, on the concrete cushion 8, adopt grey brick masonry to build the water collecting well 2, and the water collecting well 2 is arranged on the concrete cushion 8 on the outside of the basement floor 5 and the basement outer wall 6 to be poured in rows and columns;

e, laying the lower geotextile 10 on the concrete cushion 8, and laying a reverse filter layer on the lower geotextile 10;

f, install the drainage underdrain 1 on the top surface of the anti-filter layer, and connect all the water collection wells 2 and the dewatering wells 3 at the four corners of the basement outer wall 6 through the drainage underdrain 1 to form a drainage grid;

g. Lay the upper geotextile 21 on the top surface of the anti-filter layer and the drainage ditch 1; backfill the cover soil layer 12 on the top surface of the upper geotextile 21 to the bottom surface elevation of the basement floor 5 and compact it;

h, complete the concrete pouring construction of the basement floor 5 and the basement exterior wall 6 on the top surface of the covering soil layer 12; backfill soil to the exterior ground 7 elevation on the outside of the basement exterior wall 6 and compact it;

i. Build a water storage sedimentation tank 4 on the side of the wellhead of the dewatering well 3; and install a floating ball valve 14 and a submersible pump 13 at the bottom of the dewatering well 3, and the submersible pump 13 pumps the water in the dewatering well 3 to the water storage through the water pump 15 The sedimentation tank 4 is reused after sedimentation.

In the above method, the drainage ditch 1 is laid with a finished ∩-shaped groove; the lower opening of the ∩-shaped groove is 400mm wide and 500mm high; When the drainage ditch 1 is laid, the connection between each ∩-shaped groove and the catchment well 2 or dewatering well 3 shall be connected by M10.0 cement mortar; % drainage slope. The reverse filter layer is composed of a pebble layer 9 and a gravel layer 22; when laying the gravel layer 22, the gravel layer 22 forms an oblique triangle stack 23 at the bottom of both sides of the drainage ditch 1; the top height of the triangular stack 23 The water inlet holes 20 on both sides of the drainage ditch 1 should be covered. When laying the upper geotextile 21 on the gravel layer 22 and the top surface of the drainage culvert 1, the geotextile should be laid close to the top surface of the drainage culvert 1 and the triangular pile 23. The pouring of the dewatering well 3 adopts the staged pouring method. During the pouring, the steel climbing ladder 16 is pre-buried on the well wall 18 on the side of the dewatering well 3; the first pouring height is higher than the basement floor 5 to be poured; After the concrete cushion layer 8, the water collecting well 2, the lower geotextile 10, the filter layer and the upper geotextile 21 are constructed, the upper dewatering well 3 is poured to the ground level.

A groundwater drainage structure at the bottom of the basement and surrounding areas of the present invention constructed according to the above method, as shown in FIGS. 1 to 3 , the structure includes dewatering wells 3 located at the four corners of the basement, and located below the basement floor 5 and outside the basement exterior wall 6 A group of water collection wells 2; a group of water collection wells 2 and the precipitation wells 3 in the four corners of the basement are connected through the drainage ditch 1; the precipitation well 3 is provided with a submersible pump 13 and a floating ball valve 14, and the submersible pump 13 is located on the bottom plate 19 of the precipitation well ; The submersible pump 13 is connected with the water storage sedimentation tank 4 to the outdoor ground 7 through the pumping pipe 15 . Drainage underdrain 1 is a connecting piece composed of a group of ∩-shaped grooves; the lower mouth of the ∩-shaped groove is 400mm wide and 500mm high; the bottom of the two side walls of the ∩-shaped groove is provided with a water inlet hole 20 with a radius of 200 mm. Between the top of the drainage ditch 1 and the bottom surface of the basement floor 5, an upper layer of geotextile 21 is arranged in sequence from bottom to top, and the top surface of the upper layer of geotextile 21 is provided with a covering soil layer 12; the bottom of the drainage ditch 1 is sequentially provided with a gravel layer 22 from top to bottom. , pebble layer 9, concrete cushion layer 8 and plain soil compaction layer 11; among them, the gravel layer 22 is provided with a triangular pile 23 on the outside of the drainage underdrain 1 to cover the water inlet hole 20 of the drainage underdrain 1.

Example

The structure of this example is shown in Figures 1 to 3, including: drainage underdrain 1, water collection well 2, dewatering well 3, water storage sedimentation tank 4, foundation pit groundwater and rainwater are distributed on the basement floor in a grid shape through the drainage underdrain 1 5 below and along the periphery of the basement exterior wall 6 for drainage, and then temporarily collect the water body through the water collection well 2 hidden at the intersection of the drainage underdrain 1, and then gradually drain the water body through the drainage underdrain 1 and the water collection well 2. In the dewatering well 3 at the four corners of the basement outer wall 6, the water level is controlled by a submersible pump 13 set in the dewatering well 3 to take a float valve 14, and then the water is pumped by the pumping pipe 15 in the dewatering well to the water storage and sedimentation tank on the outdoor ground 7 for the water body. Comprehensive utilization of recycling. Drainage underdrain 1 adopts the finished ∩-shaped groove, which is excavated in the foundation pit according to the actual situation of the site and pre-excavated and buried. On both sides of the excavation surface at the bottom of the ∩-shaped groove beyond the ∩-shaped groove by 200mm, mechanically or artificially compact the underlying soil, and pour a layer of 100mm thick concrete cushion 8 on the plain soil compaction layer 11, covered with a layer of geotextile as a A layer of pebble layer 9 and a layer of crushed stone layer 22 are laid at the bottom of the ∩-shaped groove as a reverse filter layer, and then the ∩-shaped groove is placed, and the connection of the ∩-shaped groove is fixed with M10.0 cement mortar. The vertical drainage gradient of the ∩-shaped groove is 0.5%. The pebble layer 9 and the gravel layer 22 are laid on both sides of the ∩-shaped groove to form a triangular pile 23 and covered with a layer of geotextile as a mud-separating sand layer. Then fill the cover soil layer 12 in the ∩-shaped groove, and then carry out the construction of the basement floor. The groundwater and rainwater of the foundation pit enter the drainage underdrain 1 through blocks to be led to the collection well 2. The side wall of the water collecting well 2 is built with lime-sand bricks, and the cover plate is made of reinforced concrete prefabricated slabs. The size of the hidden water collecting well 2 is 1.0m high, 1.0m wide and 1.5m long. A dewatering well 3 is arranged around the basement exterior wall 6. The dewatering well 3 adopts a reinforced concrete structure, and the inner side uses the side wall of the basement shear wall. Decrease the floor level by 3m to the outdoor ground level. The dewatering well 3 is constructed synchronously with the connected basement exterior wall 6 . The groundwater and rainwater of the foundation pit are diverted and drained into the precipitation well 3 through the drainage ditch 1 and the water collecting well 2 . The bottom of the dewatering well 3 is equipped with a submersible pump 13 of the type according to the water volume. The dewatering well 3 is provided with a DN100 galvanized steel pipe as the water pumping pipe 15 to pump the water body from the dewatering well 3 to the water storage sedimentation tank 4 on the outdoor ground 7. The ball valve 14 controls the water level in the dewatering well 3 . After the water body pumped to the storage sedimentation tank 4 is subjected to sedimentation treatment, the water body can be comprehensively utilized for water resources according to the actual construction on site.

The invention effectively utilizes the idea of "combination of reduction and discharge, comprehensive utilization" by draining and collecting groundwater and rainwater under the bottom plate and around the basement outer wall into the dewatering well, and then extracting the water body into the outdoor water storage sedimentation tank through the dewatering well. This solves the problem of drainage during foundation pit construction, speeds up construction, converts construction wastewater into reclaimed water for comprehensive utilization of water resources, saves water and reduces construction costs, reduces groundwater pressure, and avoids basement floor and basement exterior walls. Leakage risk ensures project quality.

Claims (10)

1. A basement bottom and periphery underground water drainage method is characterized in that: the method is that criss-cross drainage blind ditches are arranged at the periphery and the bottom of the basement, water collecting wells are arranged at criss-cross intersection points to temporarily collect water from the drainage blind ditches and then lead the water to precipitation wells positioned at four corners of the outer wall of the basement, water in the precipitation wells is pumped to a water storage sedimentation tank on the outdoor ground through submersible pumps in the precipitation wells, and the water after sedimentation is reused as construction water.

2. The underground water drainage method at the bottom and the periphery of the basement according to claim 1, characterized in that: the construction steps of the method are as follows:

when the basement foundation pit is excavated, excavating the foundation pit to be below 200mm of the bottom surface of the basement bottom plate;

continuously digging down to a deep pit 3m below the elevation of the basement bottom plate at four corners of the basement outer wall, and then pouring a precipitation well in the deep pit by adopting reinforced concrete;

tamping the bottom of the foundation pit to form a soil ramming layer; pouring a concrete cushion layer with the thickness of 100mm on the top surface of the plain soil rammed layer;

building water collecting wells on the concrete cushion layer by using gray bricks, wherein the water collecting wells are arranged on the concrete cushion layer on the outer side of the basement bottom plate and the basement outer wall to be poured in a row-column mode;

laying a lower layer of geotextile on the concrete cushion layer, and laying a reverse filter layer on the lower layer of geotextile;

installing drainage underdrains on the top surfaces of the inverted filter layers, and connecting all the water collecting wells and precipitation wells positioned at four corners of the outer wall of the basement into a whole through the drainage underdrains to form drainage grids;

laying an upper geotextile layer on the top surfaces of the inverted filter layer and the drainage blind ditch; backfilling a covering soil layer on the top surface of the upper geotechnical cloth to the elevation of the bottom surface of the basement bottom plate and tamping;

completing concrete pouring construction of the basement bottom plate and the basement outer wall on the top surface of the covering soil layer; backfilling outside the basement outer wall to the outdoor ground elevation and tamping;

constructing a water storage sedimentation tank on one side of a wellhead of the dewatering well; and a ball float valve and a submersible pump are arranged at the bottom of the precipitation well, and the submersible pump pumps water in the precipitation well to a water storage sedimentation tank through a water pumping pipe and then the water is reused after sedimentation.

3. The underground water drainage method at the bottom and the periphery of the basement according to claim 2, wherein the drainage blind ditches are laid by using ∩ -shaped grooves, the bottom opening of the ∩ -shaped groove is 400mm in width and 500mm in height, and semicircular holes with the radius of 200mm are arranged in the middles of the bottoms of the two side walls of the ∩ -shaped groove and are used as water inlet holes.

4. The underground water draining method for basement bottom and periphery according to claim 3, wherein when the drainage underdrains are laid, the connection between each section of ∩ -shaped groove and the connection between the collection well or the dewatering well are connected by M10.0 cement mortar, and the drainage underdrains are laid in a mode of keeping the middle high and the four corners low, so that a drainage slope of 0.5% is formed.

5. The basement bottom and periphery groundwater drainage method according to claim 2, characterized in that: the inverted filter layer consists of a pebble layer and a crushed stone layer; when the crushed stone layer is laid, the crushed stone layer forms inclined triangular piles at the bottoms of the two sides of the drainage blind ditch; the triangular piled top height covers the water inlet holes at the two sides of the drainage blind ditch.

6. The underground water drainage method at the bottom and around the basement according to claim 5, characterized in that: when the upper geotextile is laid on the gravel layer and the top surface of the drainage blind ditch, the geotextile is tightly attached to the top surface of the drainage blind ditch and piled up in a triangular shape for laying.

7. The basement bottom and periphery groundwater drainage method according to claim 2, characterized in that: the pouring of the dewatering well adopts a sectional pouring mode, and a steel ladder stand is embedded in the well wall on one side of the dewatering well during pouring; the first pouring height is higher than the elevation of the basement bottom plate to be poured; and pouring an upper section dewatering well to the ground elevation after the construction of the plain soil tamping layer, the concrete cushion layer, the water collecting well, the lower geotextile, the reverse filter layer and the upper geotextile is completed.

8. The basement bottom and surrounding underground water drainage structure formed by the basement bottom and surrounding underground water drainage method according to any one of claims 1 to 7 comprises dewatering wells (3) positioned at four corners of the basement and a group of water collecting wells (2) positioned below a basement bottom plate (5) and outside a basement outer wall (6); the method is characterized in that: the water collecting wells (2) are connected with dewatering wells (3) at four corners of the basement through drainage blind ditches (1); a submersible pump (13) and a ball float valve (14) are arranged in the dewatering well (3), and the submersible pump (13) is positioned on a dewatering well bottom plate (19); the submersible pump (13) is connected with a water storage sedimentation tank (4) on the outdoor ground (7) through a water pumping pipe (15).

9. The underground water drainage structure at the bottom and the periphery of the basement according to claim 8, wherein the drainage blind ditch (1) is a connecting piece formed by a group of ∩ -shaped grooves, the width of the lower opening of the ∩ -shaped groove is 400mm, the height of the lower opening of the ∩ -shaped groove is 500mm, and the middle of the bottoms of two side walls of the ∩ -shaped groove is provided with a water inlet hole (20) with the radius of 200 mm.

10. The basement bottom and periphery groundwater drainage structure of claim 8, characterized in that: an upper geotextile (21) is sequentially arranged between the top of the drainage blind ditch (1) and the bottom surface of the basement bottom plate (5) from bottom to top, and a covering soil layer (12) is arranged on the top surface of the upper geotextile (21); a gravel layer (22), a pebble layer (9), a concrete cushion layer (8) and a plain soil tamping layer (11) are sequentially arranged below the drainage underdrain (1) from top to bottom; wherein, the gravel layer (22) is provided with a triangular pile (23) outside the drainage blind ditch (1) to cover the water inlet hole (20) of the drainage blind ditch (1).

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