An active anti-buoyancy device for basement drainage and pressure reduction and its design method

Abstract

This invention provides an active anti-buoyancy device for basement drainage and pressure reduction. The drainage ditch is located in the basement, with drainage holes within the ditch. A filter pipe, made of seamless steel, is installed in the drainage hole. Water inlets are evenly distributed along the pipe wall to form a screen. The filter pipe is surrounded by wire mesh and filled with quartz sand filter media. The filter pipe has an openable bottom plate, and its top plate is welded to the pipe and its handle. Water outlets are evenly distributed along the circumference of the top plate. A rubber pad is added at the contact point between the top plate and the drainage ditch. The drainage ditch is covered with a grate cover. This invention offers advantages such as simple construction, low cost, short construction period, easy maintenance, and easy replacement. It can be implemented simultaneously with the main project in new construction projects or used to treat basement buoyancy issues in existing projects. It solves the buoyancy problem and avoids secondary problems such as foundation voids caused by drainage and pressure reduction.

Description

Technical Field

[0001] This invention relates to an active anti-buoyancy device and design method for basement drainage and pressure reduction, belonging to the field of building anti-buoyancy technology. Background Technology

[0002] With the continuous development of urban construction and the constant changes in site hydrogeological conditions due to environmental factors, the problem of building buoyancy is becoming increasingly serious. Passive anti-buoyancy construction is difficult, has a long construction period, and is costly. The key is that the design and construction are based on the hydrogeological conditions during the construction period. When the hydrogeological conditions change later and anti-buoyancy problems occur, it is necessary to strengthen passive anti-buoyancy measures or add active anti-buoyancy measures. The operation, maintenance, and post-construction treatment are difficult and costly, which are a kind of passive static anti-buoyancy measures with insufficient dynamic adjustment capabilities. Therefore, it is necessary to study a device with low construction difficulty, low cost, short construction period, easy maintenance, and easy replacement from the perspective of active anti-buoyancy. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides an active anti-buoyancy device and design method for basement drainage and pressure reduction. This active anti-buoyancy device and design method for basement drainage and pressure reduction has advantages such as simple construction, low cost, short construction period, easy maintenance, and easy replacement. It belongs to an active dynamic anti-buoyancy measure, and the later operation, maintenance, and treatment of defects are easy. It can be used during the construction period to prevent post-construction anti-buoyancy defects, and can also be used to treat post-construction anti-buoyancy defects in basements with insufficient anti-buoyancy. It solves the basement anti-buoyancy problem and avoids the secondary defect problem of foundation voiding caused by drainage and pressure reduction.

[0004] The present invention is achieved through the following technical solutions.

[0005] This invention provides an active anti-buoyancy device for basement drainage and pressure reduction, comprising a drainage ditch; the bottom of the drainage ditch is provided with multiple drainage holes, each drainage hole being equipped with a filter pipe, the filter pipe being connected to the drainage ditch; the top of the drainage ditch is provided with a grate cover, and the drainage ditch is connected to a basement sump; the filter pipe is wrapped with wire mesh, and the filter pipe is filled with quartz sand filter media; a filter pipe top plate is connected to the top of the filter pipe, the filter pipe top plate is located inside the drainage ditch, and an openable filter pipe bottom plate is connected to the bottom of the filter pipe; multiple filter pipe outlet holes are evenly provided on the filter pipe top plate, and filter pipe handles are welded to both sides of the upper end face of the filter pipe top plate, and a rubber pad is provided at the contact point between the filter pipe top plate and the drainage ditch.

[0006] The total drainage volume of the drainage ditch is greater than or equal to the total outflow volume of the drainage hole; the total water storage and pumping volume of the basement sump is greater than or equal to the total outflow volume of the drainage hole.

[0007] The filter pipe is a seamless steel pipe, and multiple evenly distributed water inlet holes are provided on the pipe wall to form a screen pipe.

[0008] The bottom of the drainage ditch is also provided with additional drainage holes, which are located at the boundary of the basement.

[0009] The drainage ditch is located in the basement. When there is a waterproof layer in part of the basement, the drainage hole extends through the waterproof layer into the aquifer.

[0010] The water outlet of the filter pipe is located within the circumference of the filter pipe.

[0011] The filter pipe, wire mesh, filter pipe bottom plate, filter pipe top plate, and filter pipe handle are all protected against corrosion using anti-corrosion measures.

[0012] The quartz sand filter media has a particle size larger than that of the wire mesh, the inlet hole of the filter pipe, and the outlet hole of the filter pipe, and the particle size is uniform.

[0013] A design method for an active anti-buoyancy device for basement drainage and pressure reduction includes the following steps:

[0014] ①Based on the hydraulic gradient i of a single drainage hole in a semi-infinite space and the anti-buoyancy head height h of the basement. j and the critical head height h of the drainage hole p The radius of influence r of a single drainage hole in the basement is obtained by the following formula:

[0015]

[0016] Where, r is the radius of influence of a single drainage hole in the basement; i is the hydraulic gradient of a single drainage hole in the semi-infinite space; h j h is the anti-buoyancy head height of the basement. p The critical head height at the outlet;

[0017] ② When the drainage holes are arranged in a quincunx pattern, the calculation formula for the spacing is as follows:

[0018]

[0019] d y =1.5r

[0020] Where, d x The spacing between the drainage holes when arranged in a plum blossom pattern; d y is the spacing between the drainage holes when arranged in a quincunx pattern; r is the radius of influence of a single drainage hole on the basement.

[0021] When using a square layout, the formula for calculating the spacing is as follows:

[0022]

[0023] Where d represents the spacing between drainage holes and the spacing between rows when arranged in a square pattern; r represents the drainage influence radius (m) of a single drainage hole in the basement.

[0024] ③ Arrange drainage holes in the basement according to the arrangement and spacing of the drainage holes. Some drainage holes need to be added at the boundary of the basement, so as to obtain the total number n of drainage holes that need to be arranged in the basement.

[0025] ④ Calculate the basement water inflow Q using the following formula:

[0026]

[0027] Where Q is the water inflow volume of the basement; A is the area enclosed by the line connecting the centers of the drainage holes at the basement boundary; H is the thickness of the unconfined aquifer; h p The critical head height at the outlet; k is the aquifer permeability coefficient; l is the length of the filter pipe inlet section; h j The anti-buoyancy head height for the basement;

[0028] ⑤ By combining the basement water inflow Q with the number of filter pipes n, and considering the safety factor λ, obtain the single-pipe outflow q of the drain hole:

[0029]

[0030] Where q is the water flow rate of a single drain hole; n is the number of drain holes; λ is the safety factor, which is taken as 1.0 to 1.2; and Q is the water inflow rate in the basement.

[0031] ⑥ Calculate the length l of the inlet section of the filter pipe according to the following formula:

[0032]

[0033] Where l is the length of the inlet section of the filter pipe; d is the radius of the filter pipe, which is 90-130 mm; n e The effective porosity of the filter pipe is taken as 50% of the porosity of the inlet surface of the filter pipe; k is the aquifer permeability coefficient; q is the single-pipe outflow rate of the drain hole.

[0034] ⑦ Determine the layout of the drainage ditch based on the arrangement of the drainage holes. Determine the drainage volume of the drainage ditch based on the number of drainage holes in the drainage ditch, the water output of a single drainage hole, and the connection of the drainage ditch. Calculate the cross-sectional dimensions using the following formula: First, assume b = h to obtain the cross-sectional area S of the water passage. Then, adjust the values ​​of b and h to make bh = S, thereby determining the cross-sectional dimensions of the drainage ditch:

[0035]

[0036] a = h + c

[0037] Where μ is the drainage ditch coarseness coefficient; m represents the water output of m filter pipes that this section of the drainage ditch needs to absorb; q is the water output of a single drain hole; b is the design net width of the drainage ditch; h is the design water level height; I is the hydraulic slope of the drainage ditch; a is the design net height of the drainage ditch; and c is the distance from the top of the ditch to the design water level, which is taken as 0.2m.

[0038] The basement water inflow volume in step ④ is the basement anti-buoyancy head height h. j Critical head height h at the outlet p The water inflow rate is determined at a given time, and the water head line in the basement at this time is a virtual water head line.

[0039] The beneficial effects of this invention are as follows: it has the advantages of simple construction, low cost, short construction period, easy maintenance and easy replacement. It belongs to a proactive dynamic anti-buoyancy measure, and the operation, maintenance and treatment of defects in the later stage of the project are easy. When applied during the construction period, it can prevent post-construction anti-buoyancy defects, and can also treat post-construction anti-buoyancy defects in basements with insufficient anti-buoyancy. It not only solves the anti-buoyancy problem of basements, but also avoids the secondary defect problem of foundation voiding caused by water drainage and pressure reduction. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the planar layout of the present invention;

[0041] Figure 2 This is a cross-sectional schematic diagram of the present invention;

[0042] Figure 3 This is a simplified diagram illustrating the calculation of the influence radius of the drainage hole in an embodiment of the present invention.

[0043] Figure 4 This is a schematic diagram of the plum blossom-shaped arrangement of drainage holes in an embodiment of the present invention;

[0044] Figure 5 This is a simplified diagram for calculating the basement water inflow in an embodiment of the present invention;

[0045] Figure 6 This is a schematic diagram of the drainage ditch design cross-section in an embodiment of the present invention;

[0046] Figure 7 This is a flowchart of the present invention;

[0047] In the diagram: 1-Drainage ditch, 2-Drainage hole, 3-Filter pipe, 4-Wire mesh, 5-Quartz sand filter media, 6-Filter pipe bottom plate, 7-Filter pipe top plate, 8-Filter pipe handle, 9-Filter pipe inlet, 10-Filter pipe outlet, 11-Rubber pad, 12-Water grate cover, 13-Basement sump, 14-Anti-buoyancy head line, 15-Single-hole drainage head line, 16-Additional drainage hole, 17-Initial water level line, 18-Drainage water level line, 19-Virtual head line, 20-Design water level line of drainage ditch. Detailed Implementation

[0048] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0049] Example 1

[0050] like Figures 1-6 As shown, a basement drainage pressure reduction active anti-buoyancy device includes a drainage ditch 1 arranged in the basement; the bottom of the drainage ditch 1 is provided with multiple drainage holes 2, each drainage hole 2 is provided with a filter pipe 3, and the filter pipe 3 is connected to the drainage ditch 1; the top of the drainage ditch 1 is provided with a grate cover plate 12, and the drainage ditch is connected to the basement sump 13; the filter pipe 3 is wrapped with a wire mesh 4, and the filter pipe 3 is filled with quartz sand filter material 5; the top of the filter pipe 3 is connected to a filter pipe top plate 7, which is located in the drainage ditch 1, and the bottom of the filter pipe 3 is connected to an openable filter pipe bottom plate 6; multiple filter pipe outlet holes 10 are evenly provided on the filter pipe top plate 7, and filter pipe handles 8 are welded on both sides of the upper end face of the filter pipe top plate 7, and rubber pads 11 are provided at the contact point between the filter pipe top plate 7 and the drainage ditch 1.

[0051] The total drainage volume of the drainage ditch 1 is greater than or equal to the total outflow volume of the drainage hole 2; the total water storage and pumping volume of the basement sump 13 is greater than or equal to the total outflow volume of the drainage hole 2.

[0052] The filter pipe 3 is a seamless steel pipe, and multiple evenly distributed filter pipe inlet holes 9 are provided on the pipe wall of the filter pipe 3 to form a screen pipe.

[0053] The bottom of the drainage ditch 1 is also provided with an additional drainage hole 16, which is located at the boundary of the basement.

[0054] The drainage ditch 1 is located in the basement. When there is a waterproof layer in part of the basement, the drainage hole 2 extends through the waterproof layer into the water-bearing layer.

[0055] The water outlet 10 of the filter pipe is located within the circumference of the filter pipe 3.

[0056] The filter pipe 3, wire mesh 4, filter pipe bottom plate 6, filter pipe top plate 7, and filter pipe handle 8 are all protected against corrosion using anti-corrosion measures.

[0057] The particle size of the quartz sand filter media 5 is larger than that of the wire mesh 4, the water inlet hole 9 of the filter pipe, and the water outlet hole 10 of the filter pipe, and the particle size is uniform.

[0058] like Figure 7 As shown, a design method for an active anti-buoyancy device for basement drainage and pressure reduction includes the following steps:

[0059] ①Based on the hydraulic gradient i of a single drainage hole in a semi-infinite space and the anti-buoyancy head height h of the basement. j and the critical head height h of the drainage hole p The radius of influence r of a single drainage hole in the basement is obtained by the following formula:

[0060]

[0061] Where, r is the radius of influence of a single drainage hole in the basement; i is the hydraulic gradient of a single drainage hole in the semi-infinite space; h j h is the anti-buoyancy head height of the basement. p The critical head height at the outlet;

[0062] ② When the drainage holes are arranged in a quincunx pattern, the calculation formula for the spacing is as follows:

[0063]

[0064] d y =1.5r

[0065] Where, d x The spacing between the drainage holes when arranged in a plum blossom pattern; d y is the spacing between the drainage holes when arranged in a quincunx pattern; r is the radius of influence of a single drainage hole on the basement.

[0066] When using a square layout, the formula for calculating the spacing is as follows:

[0067]

[0068] Where d represents the spacing between drainage holes and the spacing between rows when arranged in a square pattern; r represents the drainage influence radius (m) of a single drainage hole in the basement.

[0069] ③ Arrange drainage holes in the basement according to the arrangement and spacing of the drainage holes. Some drainage holes need to be added at the boundary of the basement, so as to obtain the total number n of drainage holes that need to be arranged in the basement.

[0070] ④ Calculate the basement water inflow Q using the following formula:

[0071]

[0072] Where Q is the water inflow volume of the basement; A is the area enclosed by the line connecting the centers of the drainage holes at the basement boundary; H is the thickness of the unconfined aquifer; h p The critical head height at the outlet; k is the aquifer permeability coefficient; l is the length of the filter pipe inlet section; h j The anti-buoyancy head height for the basement;

[0073] ⑤ By combining the basement water inflow Q with the number of filter pipes n, and considering the safety factor λ, obtain the single-pipe outflow q of the drain hole:

[0074]

[0075] Where q is the water flow rate of a single drain hole; n is the number of drain holes; λ is the safety factor, which is taken as 1.0 to 1.2; and Q is the water inflow rate in the basement.

[0076] ⑥ Calculate the length l of the inlet section of the filter pipe according to the following formula:

[0077]

[0078] Where l is the length of the inlet section of the filter pipe; d is the radius of the filter pipe, which is 90-130 mm; n e The effective porosity of the filter pipe is taken as 50% of the porosity of the inlet surface of the filter pipe; k is the aquifer permeability coefficient; q is the single-pipe outflow rate of the drain hole.

[0079] ⑦ Determine the layout of the drainage ditch based on the arrangement of the drainage holes. Determine the drainage volume of the drainage ditch based on the number of drainage holes in the drainage ditch, the water output of a single drainage hole, and the connection of the drainage ditch. Calculate the cross-sectional dimensions using the following formula: First, assume b = h to obtain the cross-sectional area S of the water passage. Then, adjust the values ​​of b and h to make bh = S, thereby determining the cross-sectional dimensions of the drainage ditch:

[0080]

[0081] a = h + c

[0082] Where μ is the drainage ditch coarseness coefficient; m represents the water output of m filter pipes that this section of the drainage ditch needs to absorb; q is the water output of a single drain hole; b is the design net width of the drainage ditch; h is the design water level height; I is the hydraulic slope of the drainage ditch; a is the design net height of the drainage ditch; and c is the distance from the top of the ditch to the design water level, which is taken as 0.2m.

[0083] The basement water inflow volume in step ④ is the basement anti-buoyancy head height h. j Critical head height h at the outlet p The water inflow rate is determined at a given time, and the water head line in the basement at this time is a virtual water head line.

[0084] Example 2

[0085] like Figures 1-6As shown, a basement drainage pressure-reducing active anti-buoyancy device mainly includes a drainage ditch, drainage holes, and filter pipes. The drainage ditch is located in the basement, and multiple drainage holes are evenly distributed within the drainage ditch. The filter pipes are installed within the drainage holes. The drainage ditch is connected to the basement sump, and the drainage ditch cover is a grate cover. The filter pipes are made of seamless steel pipes, with filter pipe inlet holes evenly distributed on the pipe wall to form a screen pipe. The filter pipes are wrapped with wire mesh, and the inside of the pipes is filled with... The filter pipe is filled with quartz sand filter media. The bottom plate of the filter pipe can be opened. The top plate of the filter pipe is welded to the filter pipe and the handle. The filter pipe outlet holes are evenly distributed on the top plate within the circumference of the filter pipe. A rubber pad is added at the contact point between the top plate of the filter pipe and the drainage ditch. The filter pipe, wire mesh, bottom plate, top plate and handle are protected against corrosion. The quartz sand has a particle size larger than the inlet and outlet holes of the filter pipe and the pore size of the wire mesh and the particle size is uniform.

[0086] Furthermore, the drainage volume of the drainage ditch is greater than or equal to the total outflow of the drainage holes in the drainage ditch, and the water storage and pumping volume of the basement sump are greater than or equal to the total outflow of the drainage holes in the basement.

[0087] Preferably, when there is a waterproof layer in a part of the basement, the drainage hole should penetrate the waterproof layer and extend into the aquifer to meet the single-hole water output requirement.

[0088] like Figure 7 As shown, a design method for an active anti-buoyancy device for basement drainage and pressure reduction involves the following steps:

[0089] Step 1: Based on the hydraulic gradient i of a single drain hole in a semi-infinite space and the anti-buoyancy head h of the basement... j and the critical head height h of the drainage hole p The radius of influence r of a single drain hole in the basement can be calculated using the following simplified formula.

[0090]

[0091] In the formula, r is the radius of influence of a single drainage hole in the basement (m); i is the hydraulic gradient of a single drainage hole in a semi-infinite space; h j The anti-buoyancy head height of the basement (m); h p The critical head height (m) at the outlet.

[0092] Step 2: The recommended arrangement of the drainage holes is a quincunx pattern, and the spacing between them should be calculated using the following formula.

[0093]

[0094] d y =1.5r

[0095] In the formula dx When arranged in a quincunx pattern, the spacing between the drainage holes (m); d y The spacing between the drainage holes in a quincunx pattern (m); r is the radius of influence of a single drainage hole in the basement (m).

[0096] When using a square layout, the spacing between the elements is calculated using the following formula.

[0097]

[0098] In the formula, d represents the spacing between drainage holes and the spacing between rows when the layout is square (m); r represents the radius of influence of a single drainage hole in the basement (m).

[0099] Step 3: Arrange drainage holes in the basement according to the layout and spacing of the drainage holes. Some drainage holes need to be added at the boundary of the basement. This will give the total number n of drainage holes that need to be arranged in the basement.

[0100] Step 4: Calculate the basement water inflow Q using the following formula.

[0101]

[0102] In the formula, Q represents the basement water inflow (m³ / d); A represents the area enclosed by the line connecting the centers of the drainage holes at the basement boundary (m²). 2 H is the thickness of the unconfined aquifer (m); h p is the critical head height at the outlet (m); k is the aquifer permeability coefficient (m / d); l is the length of the filter pipe inlet section (m); h j The anti-buoyancy head height (m) of the basement.

[0103] Step 5: Calculate the single-pipe outflow rate q of the drainage hole by using the basement water inflow rate Q, the number of filter pipes n, and considering the safety factor λ.

[0104]

[0105] In the formula, q is the water output of a single drain hole (m / d); n is the number of drain holes; λ is the safety factor, which is generally taken as 1.0 to 1.2; and Q is the water inflow of the basement (m / d).

[0106] Step 6: Calculate the length l of the water inlet section of the filter pipe according to the following formula.

[0107]

[0108] In the formula, l is the length of the inlet section of the filter pipe (m); d is the radius of the filter pipe (m), generally taken as 90-130mm; n eThe effective porosity of the filter pipe is taken as 50% of the porosity of the inlet surface of the filter pipe; k is the aquifer permeability coefficient (m / d); q is the single-pipe outflow rate of the drain hole (m / d).

[0109] Step 7: Determine the layout of the drainage ditch according to the arrangement of the drainage holes. Determine the drainage volume of the drainage ditch based on the number of drainage holes in the drainage ditch, the water output of a single drainage hole, and the connection of the drainage ditch. Calculate the optimal cross-section using software or estimate the cross-sectional dimensions using the following formula. You can first assume b = h to calculate the cross-sectional area S, and then adjust the values ​​of b and h to make bh = S, thereby determining the cross-sectional dimensions of the drainage ditch.

[0110]

[0111] a = h + c

[0112] In the formula, μ is the drainage ditch coarseness coefficient; m represents the amount of water that the drainage ditch needs to absorb from m filter pipes; q is the single-pipe water discharge of the drainage hole (m / d); b is the design net width of the drainage ditch (m); h is the design water level height (m); I is the hydraulic slope of the drainage ditch; a is the design net height of the drainage ditch; and c is the distance between the top of the ditch and the design water level, which is generally taken as 0.2m.

[0113] Specifically, in step four, the water inflow in the basement is the basement's anti-buoyancy head height h. j Critical head height h at the outlet p The calculated inflow volume is slightly larger than the actual inflow volume, meaning the design is slightly conservative.

Claims

1. A design method for an active anti-buoyancy device for basement drainage and pressure reduction, characterized in that: The device includes a drainage ditch (1), characterized in that: the bottom of the drainage ditch (1) is provided with a plurality of drainage holes (2), each drainage hole (2) is provided with a filter pipe (3), the filter pipe (3) is connected to the drainage ditch (1); the top of the drainage ditch (1) is provided with a grate cover plate (12), and the drainage ditch (1) is connected to the basement sump (13); the filter pipe (3) is wrapped with a wire mesh (4), and the filter pipe (3) is filled with quartz sand filter material (4). 5) The top of the filter pipe (3) is connected to a filter pipe top plate (7), which is located in the drainage ditch (1). The bottom of the filter pipe (3) is connected to an openable filter pipe bottom plate (6). The filter pipe top plate (7) is evenly provided with multiple filter pipe outlet holes (10). Filter pipe handles (8) are welded to both sides of the upper end face of the filter pipe top plate (7). Rubber pads (11) are provided at the contact point between the filter pipe top plate (7) and the drainage ditch (1). The method includes the following steps: ①Based on the hydraulic gradient of a single spillway in a semi-infinite space Basement anti-buoyancy head height and the critical head height at the outlet. Obtain the radius of influence of a single drain hole in the basement. The formula is as follows: in, The radius of influence of a single drain hole in the basement; The hydraulic gradient for a single drain hole in a semi-infinite space; The anti-buoyancy head height for the basement; The critical head height at the outlet; ② When the drainage holes are arranged in a quincunx pattern, the calculation formula for the spacing is as follows: in, The spacing between the drainage holes when arranged in a plum blossom pattern; The spacing between the drainage holes when arranged in a plum blossom pattern; The radius of influence of a single drain hole in the basement; When using a square layout, the formula for calculating the spacing is as follows: in, When the layout is square, the spacing between the drainage holes and the spacing between the drain holes should be considered. The radius of influence of a single drain hole in the basement; ③ Install drainage holes in the basement according to the layout and spacing of the drainage holes. Additional drainage holes are required at the basement boundary. This will determine the number of filter pipes that need to be installed in the basement. ; ④ Calculate the basement water inflow using the following formula. : in, This refers to the water inflow volume in the basement. The area enclosed by the line connecting the centers of the drainage holes at the boundary of the basement; This refers to the thickness of the unconfined aquifer. The critical head height at the outlet; The aquifer permeability coefficient; This refers to the length of the inlet section of the filter pipe. The anti-buoyancy head height for the basement; ⑤ Water flow through the basement With the number of filter pipes And taking safety factor into account Obtain the water output of a single drain hole. : in, This refers to the water output of a single drain hole; This refers to the number of filter pipes; For safety, a factor of 1.0 to 1.2 is used; This refers to the water inflow volume in the basement. ⑥ Calculate the length of the inlet section of the filter pipe according to the following formula. : in, This refers to the length of the inlet section of the filter pipe. The radius of the filter pipe is 90–130 mm. The effective porosity of the filter pipe is taken as 50% of the porosity of the water inlet surface of the filter pipe; The aquifer permeability coefficient; This refers to the water output of a single drain hole; ⑦ Determine the layout of the drainage ditch based on the arrangement of the drainage holes. Determine the drainage volume of the drainage ditch based on the number of drainage holes, the water output per drainage hole, and the connection details. Calculate the cross-sectional dimensions using the following formulas, assuming... Obtain the cross-sectional area of ​​the water passage Adjust again , The value of makes This allows us to determine the cross-sectional dimensions of the drainage ditch. in, This refers to the roughness coefficient of the drainage ditch. This indicates that the section of the drainage ditch needs to be treated. The water output of the filter pipe; This refers to the water output of a single drain hole; Design the net width of the drainage ditch; Design water level height; The hydraulic slope of the drainage ditch; The clearance height for drainage ditches should be designed accordingly; The distance between the top of the ditch and the design water level is taken as 0.2m.

2. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The total drainage volume of the drainage ditch (1) is greater than or equal to the total outflow volume of the drain hole (2); the total water storage and pumping volume of the basement sump (13) is greater than or equal to the total outflow volume of the drain hole (2).

3. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The filter pipe (3) is a seamless steel pipe, and multiple evenly distributed filter pipe inlet holes (9) are provided on the pipe wall of the filter pipe (3) to form a screen pipe.

4. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The bottom of the drainage ditch (1) is also provided with additional drainage holes (16), which are arranged at the boundary of the basement.

5. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The drainage ditch (1) is located in the basement. When there is a waterproof layer in part of the basement, the drainage hole (2) extends through the waterproof layer into the aquifer.

6. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The water outlet (10) of the filter pipe is located within the circumference of the filter pipe (3).

7. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The filter pipe (3), wire mesh (4), filter pipe bottom plate (6), filter pipe top plate (7), and filter pipe handle (8) are all protected against corrosion using anti-corrosion measures.

8. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The particle size of the quartz sand filter media (5) is larger than that of the wire mesh (4), the water inlet hole (9) of the filter pipe, and the water outlet hole (10) of the filter pipe, and the particle size is uniform.

9. The design method of the active anti-buoyancy device for basement drainage and pressure reduction as described in claim 1, characterized in that: The basement water inflow volume in step ④ is the basement's anti-buoyancy head height. Critical head height at the outlet The water inflow rate is determined at a given time, and the water head line in the basement at this time is a virtual water head line.

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