阅读说明：本技术 一种泄水降压的地下抗浮水池及其泄水降压方法 (Underground anti-floating water pool capable of draining and reducing pressure and draining and reducing pressure method thereof ) 是由 张瑞松 朱翔 骆敏 于 2021-07-22 设计创作，主要内容包括：本发明公开了一种泄水降压的地下抗浮水池,包括水池,所述水池内部且位于水池钢筋砼底板下方设置集水坑,所述集水坑上方设有与集水坑相连通的监测井,所述监测井顶部标高大于等于水池标高,保证水池与监测井之间相互隔绝；所述水池钢筋砼底板底部设置复合反滤层,所述复合反滤层内设置排水管,所述排水管与集水坑相连通；所述监测井内设有液位调控系统,并通过液位调控系统对监测井内液位进行自动控制。本发明通过在水池底部设置常规建筑材料组成的复合反滤层,将地下水收集汇入集水坑中,消除了水池底板的水浮力,而且渗流出来的水属于清水不会带走原状土的土颗粒,不会污染环境,因此本发明属于一种经济环保的水池抗浮技术。(The invention discloses an underground anti-floating water tank capable of draining and reducing pressure, which comprises a water tank, wherein a water collecting pit is arranged in the water tank and below a reinforced concrete bottom plate of the water tank, a monitoring well communicated with the water collecting pit is arranged above the water collecting pit, and the elevation of the top of the monitoring well is greater than or equal to the elevation of the water tank, so that the mutual isolation between the water tank and the monitoring well is ensured; the bottom of the reinforced concrete bottom plate of the water pool is provided with a composite inverted filter layer, a drain pipe is arranged in the composite inverted filter layer, and the drain pipe is communicated with the sump; and a liquid level regulating and controlling system is arranged in the monitoring well, and the liquid level in the monitoring well is automatically controlled through the liquid level regulating and controlling system. According to the invention, the composite inverted filter layer made of conventional building materials is arranged at the bottom of the pool, so that underground water is collected and gathered in the water collecting pit, the water buoyancy of the bottom plate of the pool is eliminated, and the leaked water belongs to clear water, does not take away soil particles of undisturbed soil, and does not pollute the environment, so that the invention belongs to an economic and environment-friendly anti-floating technology for the pool.)

1. The underground anti-floating water pool capable of draining and reducing pressure comprises a water pool (22) and is characterized in that a water collecting pit (15) is arranged inside the water pool (22) and below a water pool reinforced concrete bottom plate (9), a monitoring well (19) communicated with the water collecting pit (15) is arranged above the water collecting pit (15), and the elevation of the top of the monitoring well (19) is greater than or equal to that of the water pool (22), so that the water pool and the monitoring well are isolated from each other; a composite inverted filter layer is arranged at the bottom of the pool reinforced concrete bottom plate (9), a drain pipe (14) is arranged in the composite inverted filter layer, and the drain pipe (14) is communicated with a sump (15); and a liquid level regulating and controlling system is arranged in the monitoring well (19), and the liquid level in the monitoring well (19) is automatically controlled through the liquid level regulating and controlling system.

2. The underground anti-floating water pool with the water drainage and pressure reduction functions as claimed in claim 1, wherein the composite inverted filter layer sequentially comprises a bamboo grate plate (2), a fine sand layer (3), a medium-coarse sand layer (4), non-woven geotextile (5), a gravel layer (6) and polyethylene color strip cloth (7), a water pool plain concrete cushion layer (8) is arranged above the polyethylene color strip cloth (7), and the water pool reinforced concrete bottom plate (9) is arranged above the water pool plain concrete cushion layer (8).

3. The underground anti-floating water tank capable of draining and reducing pressure according to claim 2, characterized in that the bamboo grate plates (2) are in direct contact with the protected soil layer (1), and are connected in a staggered lap joint manner by adopting steel wire binding.

4. The underground anti-floating water pool with the water drainage and pressure reduction functions as claimed in claim 1, wherein a vertical concrete water-stopping retaining wall (11) is arranged at the periphery of the projection range of the reinforced concrete bottom plate (9) of the water pool, and the side face of the composite reverse filter layer is limited on the vertical concrete water-stopping retaining wall (11).

5. The underground anti-floating water pool with the water drainage and pressure reduction functions as claimed in claim 1, wherein a horizontal concrete water-stopping retaining wall (12) is arranged around the projection range of the water pool reinforced concrete bottom plate (9), one end of the horizontal concrete water-stopping retaining wall (12) is connected with the water pool reinforced concrete bottom plate (9), and the other end of the horizontal concrete water-stopping retaining wall is connected with the water pool foundation pit enclosure structure (13).

6. The underground anti-floating water pool for draining and depressurizing as claimed in claim 1, wherein one end of the stainless steel tube (14) is open and extends into the water collecting pit (15), the other end is closed and is embedded into the gravel layer (6), the stainless steel tube (14) is provided with water seepage holes, and the water seepage holes are arranged along the circumferential direction of the stainless steel tube (14), and the diameter of the water seepage holes is 1/3-1/2 of the particle size of the gravel layer (6).

7. A sluicing and depressurising underground anti-floating pond according to claim 1, characterised in that the sumps (15) are arranged in the middle of the pond and the sumps (15) are communicated with each other and share one monitoring well (19).

8. A water drainage and pressure reduction underground anti-floating water pool according to claim 1, wherein when the composite inverted filter layer is isolated by the water pool structure (10), holes are formed in the water pool structure (10), and water flows on the left side and the right side of the water pool structure (10) are smooth.

9. A sluicing and depressurizing underground anti-floating water pool as claimed in claim 1, wherein the liquid level regulating and controlling system comprises a liquid level meter (16), a water pump (17) with a control valve and a rainwater ditch (18), the liquid level meter (16) is arranged in the monitoring well (19) and used for monitoring the water level of the monitoring well (19) and draining accumulated water in the water collecting pit (15) into the rainwater ditch (18) through the water pump (17) with the control valve.

10. A method for depressurizing a drain of an underground anti-floating water pool according to any one of claims 1 to 9, comprising the steps of:

1) the normal using state of the pool is that when water exists in the pool:

considering that when the normal use state of the pool is that water exists in the pool, the maximum water head pressure which can be borne by the underground pool without integral floating is taken as the highest water level of the monitoring well; the maximum water level Hw of the monitoring well should meet the following formula:

Hw≤(H₁+αH₂+βH₃)/Kw

H₁-water level in the pool;

H₂-the thickness of the pool concrete floor and roof;

H₃-the thickness of the casing above the top deck of the pond;

alpha-the ratio of concrete to water specific gravity;

beta is the ratio of the specific gravity of the backfill soil to the specific gravity of the water;

kw is an anti-floating stability safety factor, wherein Kw of a class A anti-floating pool is 1.10, and Kw of a class B anti-floating pool is 1.05; 1.00 Kw of a class-C anti-floating water pool;

2) when the normal using state of the pool is that no water exists in the pool:

considering that the maximum water head pressure which can be borne by the underground water pool without generating integral floating can be used as the highest water level of the monitoring well under the normal use state that the water pool is an empty pool; the highest water level Hw of the monitoring well is in accordance with the regulation of the following calculation formula:

Hw≤(αH₂+βH₃)/Kw

kw in the formula is the anti-floating stability safety coefficient;

H₂-the thickness of the pool concrete floor and roof;

H₃-the thickness of the casing above the top deck of the pond;

alpha-the ratio of concrete to water specific gravity;

beta is the ratio of the specific gravity of the backfill soil to the specific gravity of the water;

3) the liquid level meter monitors the water level of the monitoring well, and when the liquid level in the monitoring well is higher than the highest water level, the water pump with the control valve is automatically started to discharge seepage water in the water collecting pit into the rainwater ditch; when the liquid level meter detects that the water level is lower than the water suction opening elevation of the water pump, the water pump with the control valve is automatically closed to stop pumping water.

Technical Field

The invention relates to the technical field of construction engineering construction, in particular to an underground anti-floating water pool for draining and reducing pressure and an anti-floating method.

Background

The common design method of the anti-floating of the water pool comprises three methods of a ballast weight anti-floating method, a structural anti-floating method and an anchoring anti-floating method, and the anti-floating design safety of the water pool is met by increasing the structural counterweight or increasing the anti-pulling bearing capacity.

Weight-pressing and float-resisting: the anti-floating dead weight load comprises the dead weight of the bottom plate of the underground structure and the dead weight of the upper part of the bottom plate of the underground structure, the dead weight of a structural plate which is picked out of the bottom plate of the underground structure and the dead weight of upper part earthing, the dead weight of upper part earthing of the underground structure or anti-floating bearing capacity provided by a top dead weight structure and the like. The ballast material comprises soil, gravel, grouted blockstone, concrete and the like, and is suitable for the water pool with smaller capacity and small difference of anti-floating bearing capacity.

And (3) structural float resistance: the vertical resistance is increased by increasing the rigidity of the bottom plate or the structure and the uplift bearing capacity or by utilizing a foundation pit maintenance structure. The method is suitable for projects with small anti-buoyancy distribution and uneven rigidity of the bottom plate of the underground structure, and the effective anti-buoyancy action range of the structure is small.

Anchoring and resisting the floating method: the anti-pulling bearing capacity of the anti-floating anchor rod or the anti-floating pile is utilized to ensure the safety of anti-floating design. The method has the advantages of high early construction cost, simple later maintenance and reasonable structural stress.

The ballast weight anti-floating method, the structural anti-floating method and the anchoring anti-floating method all have water buoyancy, then the anti-floating of the water pool is solved by increasing the structural resistance, the safety of the water pool is ensured by inevitably adding the structural ballast weight or anti-floating measures, and the defects of long construction period and high investment cost exist.

Therefore, the anti-floating design method of the water pool in the prior art is not perfect and has obvious defects.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides an underground anti-floating water pool for draining and reducing pressure and an anti-floating method.

The technical scheme of the invention is as follows:

the underground anti-floating water pool comprises a water pool, wherein a water collection pit is arranged inside the water pool and below a water pool reinforced concrete bottom plate, a monitoring well communicated with the water collection pit is arranged above the water collection pit, and the elevation of the top of the monitoring well is greater than or equal to the elevation of the water pool, so that the water pool and the monitoring well are isolated from each other; the bottom of the reinforced concrete bottom plate of the water pool is provided with a composite inverted filter layer, a drain pipe is arranged in the composite inverted filter layer, and the drain pipe is communicated with the sump; and a liquid level regulating and controlling system is arranged in the monitoring well, and the liquid level in the monitoring well is automatically controlled through the liquid level regulating and controlling system.

Furthermore, the composite inverted filter layer sequentially comprises a bamboo grate plate, a fine sand layer, a medium-coarse sand layer, non-woven geotextile, a gravel layer and polyethylene color stripe cloth, the bamboo grate plate is in direct contact with a protected soil layer, a pool plain concrete cushion layer is arranged above the polyethylene color stripe cloth, and a pool reinforced concrete bottom plate is arranged above the pool plain concrete cushion layer.

Furthermore, the bamboo grate plates are in direct contact with the protected soil layer, and the bamboo grate plates are connected in a staggered joint lap joint mode through steel wire binding.

Furthermore, a vertical concrete water stop retaining wall is arranged at the periphery of the projection range of the pool reinforced concrete bottom plate, and the side face of the composite reverse filter layer is limited on the vertical concrete water stop retaining wall. The periphery of pond reinforced concrete bottom plate projection scope sets up the level and links to each other to concrete stagnant water barricade one end and pond reinforced concrete bottom plate, and the other end links to each other with pond foundation ditch envelope. Reduce the seepage of surface water around the pool and flow into the water collecting pit through the permeable and water guiding layer.

Furthermore, one end opening of the stainless steel pipe extends into the water collecting pit, the other end is closed and is buried in the gravel layer, the stainless steel pipe is provided with water seepage holes, the water seepage holes are arranged along the annular direction of the stainless steel pipe, and the diameter of each water seepage hole is 1/3-1/2 of the particle size of the gravel layer.

Furthermore, the water collecting pits are arranged in the middle of the water pool, are communicated with each other and share one monitoring well; when the water collecting pits are difficult to be intensively arranged, the water collecting pits can be connected with a common monitoring well by using water pipes.

Furthermore, when the composite inverted filter layer is separated by the water pool structure, holes are formed in the water pool structure, and water flows on the left side and the right side of the water pool structure are smooth.

Further, the liquid level regulation and control system includes the level gauge, takes the water pump and the rainwater ditch of control valve, the level gauge sets up in the monitoring well for monitoring well water level, and the rainwater ditch is discharged to the ponding in with the sump pit through the water pump of taking the control valve.

A water drainage and pressure reduction method for an underground anti-floating water pool capable of draining water and reducing pressure is characterized by comprising the following steps:

1) the normal using state of the pool is that when water exists in the pool:

considering that when the normal use state of the pool is that water exists in the pool, the maximum water head pressure which can be borne by the underground pool without integral floating is taken as the highest water level of the monitoring well; the maximum water level Hw of the monitoring well should meet the following formula:

Hw≤(H₁+αH₂+βH₃)/Kw

H₁-water level in the pool;

H₂-the thickness of the pool concrete floor and roof;

H₃-the thickness of the casing above the top deck of the pond;

alpha-the ratio of concrete to water specific gravity;

beta is the ratio of the specific gravity of the backfill soil to the specific gravity of the water;

kw is an anti-floating stability safety factor, wherein Kw of a class A anti-floating pool is 1.10, and Kw of a class B anti-floating pool is 1.05; 1.00 Kw of a class-C anti-floating water pool;

2) when the normal using state of the pool is that no water exists in the pool:

considering that the maximum water head pressure which can be borne by the underground water pool without generating integral floating can be used as the highest water level of the monitoring well under the normal use state that the water pool is an empty pool; the highest water level Hw of the monitoring well is in accordance with the regulation of the following calculation formula:

Hw≤(αH₂+βH₃)/Kw

kw in the formula is the anti-floating stability safety coefficient;

H₂-the thickness of the pool concrete floor and roof;

H₃-the thickness of the casing above the top deck of the pond;

alpha-the ratio of concrete to water specific gravity;

beta is the ratio of the specific gravity of the backfill soil to the specific gravity of the water;

3) the liquid level meter monitors the water level of the monitoring well, and when the liquid level in the monitoring well is higher than the highest water level, the water pump with the control valve is automatically started to discharge seepage water in the water collecting pit into the rainwater ditch; when the liquid level meter detects that the water level is lower than the water suction opening elevation of the water pump, the water pump with the control valve is automatically closed to stop pumping water.

By adopting the technology, compared with the existing common anti-floating technology, the invention has the following beneficial effects:

1) according to the invention, the composite inverted filter layer made of conventional building materials is arranged at the bottom of the pool, so that underground water is collected and gathered in the water collecting pit, the water buoyancy of the bottom plate of the pool is eliminated, and the leaked water belongs to clear water, does not take away soil particles of undisturbed soil, and does not pollute the environment, so that the invention belongs to an economic and environment-friendly anti-floating technology for the pool.

2) Because the bearing capacity characteristic value of the uplift pile is far smaller than that of the compression pile, when the conventional anti-floating method is adopted for design, the number of the pool piles is often controlled by the number of piles designed for the uplift bearing capacity. After the water drainage and pressure reduction technology is adopted, the anti-floating head pressure of the bottom plate of the water pool can be not considered during the normal use of the water pool, and the uplift pile is not considered in the water pool. Therefore, the number of piles is saved, the construction period of the piles is shortened, and the balance weight of the water pool is reduced. The economic benefit is obvious.

3) After the water drainage and pressure reduction technology is adopted, the anti-floating head pressure of the bottom plate of the water pool can be not considered during the normal use of the water pool, and the thickness and the reinforcing bars of the bottom plate of the water pool have optimized space.

4) After the water drainage and pressure reduction technology is adopted, the shear wall which is required to be arranged in the underground water pool in the conventional design due to the anti-floating rigidity of the water pool can be omitted, only the frame column is reserved, the length of the cantilever plate required by the anti-floating counterweight at the periphery of the bottom plate of the water pool can be greatly shortened, only the anchoring lap joint length of the reinforcing steel bars of the water pool can be met, and the consumption of engineering materials for designing the water pool is greatly reduced.

5) After the water drainage and pressure reduction technology is adopted, the pool is insensitive to the change of underground water in rainy season, and the phenomena of pool floating or pool structure damage and the like caused by rainstorm can be avoided.

Drawings

FIG. 1 is a diagram of a sump arrangement according to the present invention;

FIG. 2 is a schematic view of a sump structure according to the present invention;

FIG. 3 is a view of a monitoring well arrangement of the present invention;

FIG. 4 is a schematic view of the horizontal and vertical water-stopping retaining wall structure of the present invention;

FIG. 5 is a schematic view of the structure of the composite inverted filter of the present invention;

in the figure: 1-protected weak permeable soil layer, 2-bamboo grate plate, 3-first layer of inverted filter layer-fine sand layer, 4-second layer of inverted filter layer-middle coarse sand layer, 5-non-woven geotextile, 6-third layer of inverted filter layer-gravel layer, 7-polyethylene color strip cloth, 8-pool plain concrete cushion layer, 9-pool reinforced concrete bottom plate, 10-pool structure, 11-vertical concrete water-stop wall, 12-horizontal concrete water-stop wall, 13-pool enclosure foundation pit structure, 14-stainless steel pipe with drain holes, 15-water collection pit, 16-liquid level meter, 17-water pump with control valve, 18-rain gutter, 19-monitoring well, 20-inner frame column in water pool, 21-pool wall and 22-pool.

Detailed Description

The invention will be further described with reference to the accompanying drawings in which:

as shown in fig. 1-5, the underground anti-floating water tank for draining and reducing pressure is provided with a composite inverted filter layer at the bottom of the water tank, and the method from bottom to top is as follows: the water-saving and water-saving composite material comprises a protected weak permeable soil layer 1, a bamboo grate plate 2, a first layer of inverted filter layer-fine sand layer 3, a second layer of inverted filter layer-medium coarse sand layer 4, non-woven geotextile 5, a third layer of inverted filter layer-gravel layer 6, polyethylene color strip cloth 7, a water tank plain concrete cushion layer 8 and a water tank reinforced concrete bottom plate 9. Except that the protected weak permeable soil layer 1, the pool plain concrete cushion layer 8 and the pool reinforced concrete bottom plate 9 are original soil layers or a pool structure body, other layers are specific components of the composite inverted filter layer.

Wherein the first layer of the inverted filter layer-the fine sand layer 3 and the second layer of the inverted filter layer-the medium coarse sand layer 4 are called as the permeable layer, the minimum thickness of the permeable layer is generally not less than 300mm, the third layer of the inverted filter layer-the gravel layer 6 is a water guide layer, and the stainless steel pipe 14 with the water drainage hole is arranged in the water guide layer. The total thickness of the permeable layer and the water guide layer is not less than 500 mm. The water-releasing depressurization method is suitable for the foundation soil with weak water permeability and generally requires the vertical permeability coefficient K of the weak permeable layer_V<1x10^-5cm/s, the thickness of the weakly permeable layer is not less than 1/5 of the bottom head of the water-resisting layer and not less than 2 meters.

When the composite inverted filter layer is separated by the pool structure 10 (pool ground beam or bearing platform), holes need to be formed on the ground beam to ensure that water flows of the water guide layers on the left side and the right side of the ground beam are smooth, and holes do not need to be reserved on the bearing platform due to the fact that the bearing platform has small plane projection area and has limited influence on blocking of the water flows. The open-pore ground beam or the bottom of the bearing platform 10 does not need to be provided with a composite inverted filter layer.

And a vertical concrete water-stopping retaining wall 11 and a horizontal concrete water-stopping retaining wall 12 are arranged at the periphery of the projection range of the pool reinforced concrete bottom plate 9, one end of the horizontal concrete water-stopping retaining wall 12 is connected with the pool reinforced concrete bottom plate 9, and the other end of the horizontal concrete water-stopping retaining wall is connected with a pool foundation pit support structure 13. Wherein the side of the II-type reverse filter layer (composite reverse filter layer) is folded on the vertical concrete water-stop retaining wall 11, the I-type reverse filter layer (common reverse filter layer) with the seepage direction vertical to the gravity direction is avoided, and the seepage of the surface water around the pool is reduced and the seepage flows are converged into the water collecting pit through the permeable water guide layer by increasing the seepage path of the surface water of the pool and reducing the permeability coefficient.

A horizontal water collecting system is formed by a stainless steel pipe 14 with water seepage holes, one end of the stainless steel pipe 14 with the water seepage holes is opened and extends into a water collecting pit 15, and the other end is closed and is buried in a third layer of inverted filter layer, namely a gravel layer 6 of a water guide layer; the diameter of the water seepage holes on the stainless steel pipe 14 is preferably 1/3-1/2 with smaller particle size of the crushed stone layer, and is determined according to the calculated particle grading range of the diameter of the crushed stone layer, and the water seepage holes are arranged along the circular direction of the stainless steel pipe and are preferably arranged in a quincunx shape.

When the number of the water collecting pits 15 is large, the water collecting pits 15 are preferably arranged in a centralized mode to share the monitoring well as much as possible, and when the water collecting pits are difficult to arrange in a centralized mode, the water collecting pits can be connected with the shared monitoring well through water pipes. Except the water collecting pits 15 of the monitoring wells 19, concrete slabs are arranged on the tops of the rest water collecting pits 15, and the water collecting pits 15 are communicated with each other and share one monitoring well 19. The monitoring well 19 is arranged at the upper part of one of the water collecting pits 15, the monitoring well 19 is made into a top plate of the pool from a bottom plate of the pool by using a reinforced concrete wall, the fact that seepage water collected to the water collecting pit 15 from the bottom of the pool in the monitoring well 19 and pool water outside the monitoring well 19 are not interfered with each other is guaranteed, and rainwater and sewage are guaranteed to be discharged respectively.

The method for making the composite inverted filter layer from bottom to top is as follows:

1) a bamboo grate plate:

the bamboo grate plate is in direct contact with the weak permeable layer of the protected soil layer, is suitable for silt clay with strong flow plasticity of the protected soil layer, and requires steel wire binding staggered joint lap joint connection. The bamboo grate plate is beneficial to ensuring the flatness of the working surface when people and small machinery are constructed, and preventing the protected soil layer from being mixed with the sand layer of the inverted filter layer.

2) First layer inverted filter-fine sand layer:

according to a particle grading curve of a protected soil layer provided in a geotechnical engineering investigation report ' foundation soil physical and mechanical index mathematical statistics table ', and according to requirements in appendix B of SL 274 and 2020 of rolling type earth and rockfill dam design specification ', calculating a particle grading range of a first inverted filter layer and a fine sand layer, namely an upper envelope-fine particle range line and a lower envelope-coarse particle range line.

3) Second-layer inverted filter-medium coarse sand layer:

and taking the first inverted filter layer-fine sand layer as a protective layer, and calculating the grain grading range of the second inverted filter layer-medium coarse sand layer, namely an upper envelope-fine grain range line and a lower envelope-coarse grain range line according to the requirements in appendix B of SL 274-and 2020-of rolling type earth-rock dam design specification.

4) Non-woven geotextile:

the non-woven geotextile is arranged above the permeable layer and below the water guide layer. The main purpose is to prevent the soil or piping from flowing due to the large pressure of underground water; the performance of the nonwoven geotextile material is regulated in GB/T17638 and GB/T17639, and the unit area mass of the nonwoven geotextile is preferably 300g/m²-500g/m²The tensile strength is not preferably less than 6 kN/m. The lapping length of the non-woven geotextile is not less than 500mm, and the flatness of the layer surface is not more than 10 mm/m.

5) Third layer inverted filter-rubble layer:

and (3) taking the second inverted filter layer, namely the medium coarse sand layer, as a protective layer, and calculating the grain grading ranges of the third inverted filter layer, namely an upper envelope-fine grain range line and a lower envelope-coarse grain range line according to the requirements in appendix B of SL 274-one 2020 of rolling earth-rock dam design specification.

6) Polyethylene color strip cloth:

the polyethylene color strip cloth is arranged mainly for preventing cement paste from permeating into the water guide layer when the pool bottom plate plain concrete cushion layer is poured, so that the water guide performance of the gravel layer is influenced.

Specifically, the standard of filling sand and crushed stone in the composite reverse filter layer is that relative density is used as a design control index, and the relative density of the type II reverse filter layer (composite reverse filter layer) is preferably 0.70.

Specifically, the filter material in the composite reverse filter layer adopts sand gravel and hard rock, the particles are graded continuously, and the content of the particles with the particle size of less than 0.075mm is not more than 5%.

Specifically, the filter material in the composite reverse filter layer has good water permeability, and the content of organic materials and mud in the filter material is not more than 5%.

Specifically, the gradation of the filter material in the composite reverse filter layer can be adjusted within the range of the upper envelope and the lower envelope. If the filtering soil is more important, the grading curve is closer to the characteristic grain diameter of the upper envelope; if drainage is more important, the grading curve is closer to the lower envelope characteristic particle.

An anti-floating method of an underground anti-floating water pool for draining and reducing pressure comprises the following specific steps:

the underground water pool is divided into two conditions, one is that the water is in the pool in a normal use state, and the maximum water head pressure which can be borne by the underground water pool without generating integral floating is taken as the highest water level of the monitoring well (when the water is in the pool, the weight of the water in the pool is required to be considered). The maximum water level Hw (from the bottom of the pool floor) of the monitoring well should meet the following formula:

Hw≤(H₁+αH₂+βH₃)/Kw

H₁-water level in the pool;

H₂-the thickness of the pool concrete floor and roof;

H₃-the thickness of the casing above the top deck of the pond;

alpha-the ratio of concrete to water specific gravity;

beta is the ratio of the specific gravity of the backfill soil to the specific gravity of the water;

kw is an anti-floating stability safety factor, wherein Kw of a class A anti-floating pool is 1.10, and Kw of a class B anti-floating pool is 1.05; 1.00 Kw of a class-C anti-floating water pool;

wherein alpha is generally 2.4, beta is generally 1.8; if it is considered that the specific gravity of the backfill soil is not as dense as the undisturbed soil, beta may be 1.6.

The other is that the normal using state of the water pool is an empty pool, and no water exists in the water pool at ordinary times. Only in the case of an accident in the production plant is the fire-fighting waste water collected into the basin by the waste water collection system. In the normal use state of the water pool, the underground water pool does not generate the maximum water head pressure capable of bearing the integral floating upward and is used as the highest water level of the monitoring well (when the water pool is empty, the weight of the additive does not consider the weight of water in the water pool). The maximum water level Hw of the monitoring well (from the bottom of the pool floor) should meet the specifications of the following calculation formula:

Hw≤(αH₂+βH₃)/Kw

kw in the formula is the anti-floating stability safety coefficient;

H₂-the thickness of the pool concrete floor and roof;

H₃-the thickness of the casing above the top deck of the pond;

alpha-the ratio of concrete to water specific gravity;

beta is the ratio of the specific gravity of the backfill soil to the specific gravity of the water;

in both cases the water in the ground water reservoir is sewage and the rainwater in the monitoring well 19 need to be isolated from each other and discharged separately. And the highest water level in the underground tanks is not the same as the highest water level in the monitoring well 19.

When the liquid level meter 16 detects that the water level of the monitoring well is higher than the highest water level, the water pump 17 with the control valve automatically starts to discharge seepage water in the water collecting pit 15 into the rainwater ditch 18. When the liquid level meter 16 detects that the water level is lower than the water suction opening height of the water pump, the water pump 17 with the control valve is automatically closed to stop pumping water.

In addition, in the conventional pool design, besides the pool walls 21 of the pool at the periphery of the pool, shear walls required by the anti-floating rigidity of the pool are required to be arranged between the frame columns 20 in the pool, and cantilever plates required by anti-floating balance weights are arranged at the periphery of the pool bottom plate 9. After the underground anti-floating water pool with the water drainage and pressure reduction function is adopted, the shear walls in other water pools except the pool walls 21 around the water pool and the shear walls of the monitoring wells 19 can cancel the frame columns 20 only in the reserved water pool; the length of the overhanging plate at the periphery of the pool bottom plate 9 only needs to meet the anchoring and lapping length of the pool reinforcing steel bars, so that the material consumption of the pool body can be greatly saved.

The invention eliminates the water buoyancy at the bottom of the pool by a method of draining water and reducing pressure. By means of the arrangement of the composite inverted filter layer in the hydraulic structure, the water buoyancy is avoided from the source with a small amount of investment, and the length of the cantilever plate required by the anti-floating counterweight at the periphery of the pool bottom plate is reduced by canceling the shear wall required by the anti-floating rigidity of the pool. The purposes of saving construction period and greatly saving the investment of the underground water pool are achieved.