Active and passive combined anti-floating method and device based on pressure-limiting overflow

Abstract

The invention belongs to the technical field of underground structure construction, and particularly relates to an active and passive combined anti-floating method and device based on pressure-limiting overflow. A plurality of drainage ditches are arranged in a foundation below the foundation bottom plate, permeable pipes are arranged in the drainage ditches, the pressure-limiting overflow assembly comprises a pressure-limiting pipe, the pressure-limiting pipe is arranged in a structural column, the permeable pipes penetrate into the structural column through the drainage pipes and are connected with the water inlet end of the pressure-limiting pipe, and the water outlet end of the pressure-limiting pipe extends out of the structural column. The water outlet end of the pressure limiting pipe is connected with an overflow elbow, height difference exists between an inlet and an outlet of the pressure limiting pipe, and the overflow elbow is connected with a sump through a drainage pipe. According to the method, the uncertain underground water level can be defined as the anti-floating fortification water level capable of being used for calculation, the using amount of passive uplift piles can be greatly reduced, the manufacturing cost is reduced, and unification of safety and economical efficiency of an underground structure is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of underground structure construction, and in particular relates to an active and passive combined anti-floating method and device based on pressure-limited overflow. Background Art

[0002] With the development of urbanization, the development of underground space has attracted people's attention. Underground shopping malls, underground parking lots, underground pipe galleries, subways, etc. have become powerful means to solve urban problems. Due to factors such as deep burial depth, less superstructure and small deadweight, the above-mentioned underground structures need to be designed with necessary anti-floating measures during construction to avoid floating. However, as the hydrogeological environment becomes more and more complex, especially with the frequent unpredictable extreme rainstorms, anti-floating design methods and measures are difficult to achieve the unity of safety and economy, which has become a key and difficult problem that needs to be solved urgently in the construction of underground structure engineering.

[0003] The existing anti-floating technology for underground structures is mainly passive anti-floating technology such as anti-pullout piles, anti-pullout anchors and counterweights. Passive anti-floating technology is designed based on a fixed anti-floating defense water level. Since the anti-floating defense water level often needs to take the highest historical groundwater level of the site, the amount of anti-pullout piles used in the design increases dramatically, and the project cost is very high. In addition, the frequent unpredictable extreme rainstorms in recent years have caused a sudden increase in water levels, which poses a severe challenge to the anti-floating of underground structures. That is, under the sudden increase in water levels, traditional passive anti-floating measures cannot resist buoyancy. In addition, the existing active anti-floating technology requires holes to be opened in the foundation slab to store water, and then the water is pumped out by water pumps. The holes in the foundation slab bring inconvenience to the waterproofing and construction of underground structures, and excessive drainage can easily lead to settlement and cracking of surrounding buildings and roads, which limits the scope of technology promotion.

[0004] In summary, even with high-cost passive anti-floating measures, it is difficult to cope with the severe challenges posed by unpredictable extreme rainstorms to the floating of underground structures, and there is also the problem of inconvenience in the construction of underground structures. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides an active and passive combined anti-floating method and device based on pressure-limited overflow, which can clearly define the uncertain groundwater level as an anti-floating defense water level that can be used for calculation, while reducing damage to the foundation slab.

[0006] To achieve the above object, the technical solution provided by the present invention is as follows:

[0007] In the first aspect, the present application provides an active and passive combined anti-floating device based on pressure-limited overflow, including a foundation bottom plate, which is connected to the foundation through a pile foundation, a plurality of structural columns are arranged on the foundation bottom plate, a cushion layer is provided under the foundation bottom plate, a plurality of drainage ditches are provided in the foundation under the cushion layer, a permeable pipe is provided in the drainage ditch, and also includes a pressure-limiting overflow component, the pressure-limiting overflow component includes a pressure-limiting pipe, the pressure-limiting pipe is arranged in the structural column, the permeable pipe penetrates into the structural column through the drainage pipe and is connected to the water inlet end of the pressure-limiting pipe, the water outlet end of the pressure-limiting pipe extends out of the structural column, the water outlet end of the pressure-limiting pipe is connected to an overflow elbow, there is a height difference between the inlet and outlet of the pressure-limiting pipe, and the overflow elbow is connected to a sump through a drainage pipe.

[0008] Optionally, the plurality of drainage grooves are arranged in a cross-arrangement, the plurality of drainage grooves are connected, the corresponding plurality of water-permeable pipes are connected, and the drainage grooves are arranged at the mid-span position of the structural columns on both sides thereof.

[0009] Optionally, the distance between two adjacent drainage ditches in the same direction does not exceed 20 meters.

[0010] Optionally, an outer wall is arranged on the foundation slab, structural columns are arranged inside the outer wall, drainage grooves are arranged between the outer wall and its inner adjacent structural columns, and the drainage grooves between the outer wall and its inner adjacent structural columns form a closed loop.

[0011] Optionally, an emergency pressure relief valve is provided on the pressure limiting pipe.

[0012] Optionally, the permeable pipe is provided with a seepage hole, and the drainage ditch introduces the water in the seepage ditch into the permeable pipe through the seepage hole.

[0013] Optionally, the cross-section of the drainage ditch is trapezoidal, the width of the top surface of the drainage ditch is greater than the width of the bottom surface, a water-filtration geotextile is laid around the drainage ditch, the water-filtration geotextile is filled with hydrophobic gravel, the hydrophobic gravel is arranged on the outer periphery of the permeable pipe, and the top of the hydrophobic gravel is overlapped and wrapped with the water-filtration geotextile.

[0014] Optionally, a water-isolating membrane is arranged above the hydrophobic groove, the water-isolating membrane is connected to the cushion layer, and the width of the water-isolating membrane is greater than the width of the top surface of the hydrophobic groove.

[0015] Optionally, the width of the water-blocking membrane on both sides of the drainage ditch is not less than 1 meter.

[0016] Optionally, the overflow elbow includes a horizontal section and a vertical section connected in sequence, the horizontal section is vertically connected to the water outlet end of the pressure limiting pipe, the vertical section is connected to the drain pipe, and the height of the vertical section is not less than 0.3 meters.

[0017] In a second aspect, the present application further provides an anti-floating method of the above-mentioned active and passive combined anti-floating device based on pressure-limited overflow, comprising the following steps:

[0018] S1. Determine the anti-buoyancy bearing capacity of passive measures based on the deadweight of all buildings above the pile foundation and the anti-buoyancy of the pile foundation, and define the pressure limit water level accordingly. The pressure limit water level is the installation height of the pressure limit pipe;

[0019] S2. construct a pile foundation in the foundation; dig a drainage ditch, lay a permeable pipe in the drainage ditch, and connect the permeable pipe with the drainage pipe;

[0020] S3. Cast the cushion layer and the foundation slab in sequence above the drainage ditch; connect the drainage pipe with the pressure limiting pipe when constructing the foundation slab;

[0021] S4. construct a structural column on the foundation slab, cast the lower part of the pressure limiting pipe in the structural column, and then extend the upper end of the pressure limiting pipe out of the structural column;

[0022] S5. Connect the overflow elbow at the top of the pressure limiting pipe, and the overflow elbow is connected to the drainage pipe and then connected to the sump;

[0023] S6. During use, when the groundwater level is lower than the pressure-limiting water level, the pressure-limiting overflow assembly does not work, and the passive measures consisting of the pile foundation and the deadweight of all buildings resist the buoyancy under the actual water level; when the groundwater level is higher than the pressure-limiting water level, the pressure-limiting overflow assembly starts, and the groundwater seeps into the permeable pipe under the action of water pressure, and is discharged through the pressure-limiting pipe and the overflow elbow, and the groundwater above the water level is discharged into the sump; at the same time, the passive measures continue to resist the buoyancy below the pressure-limiting water level, that is, active and passive combined anti-buoyancy.

[0024] Compared with the prior art, this application has at least the following beneficial effects:

[0025] The present invention comprehensively considers the self-weight of all buildings and the anti-buoyancy factors of the pile foundation to determine the pressure-limiting water level. For the groundwater level that is higher than the pressure-limiting water level, it is reduced through the active measures of the pressure-limiting overflow component, forming an active and passive combined anti-floating method that combines the active measures of the pressure-limiting overflow component with the passive measures composed of the self-weight of all buildings and the anti-buoyancy of the pile foundation. The pressure-limiting overflow component not only controls the water level below the pressure-limiting water level line, but also limits the amount of drainage and does not cause the settlement of surrounding buildings and roads; at the same time, the passive anti-floating measures designed according to the pressure-limiting water level line can greatly reduce the amount of anti-pullout piles and reduce the cost. Therefore, the present invention can not only clarify the uncertain groundwater level as an anti-floating defense water level that can be used for calculation, but also greatly reduce the amount of passive anti-pullout piles and reduce the cost, thereby achieving the unity of safety, stability and economy of underground structures and solving the shortcomings of existing anti-floating technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a structural schematic diagram of an active and passive combined anti-floating device based on pressure-limited overflow according to Example 2 of the present application;

[0028] Figure 2 for Figure 1 A partial enlarged view of

[0029] Figure 3 for Figure 2 Schematic diagram of the AA section structure;

[0030] Figure 4 This is a schematic structural diagram of the pressure limiting overflow assembly of the intermediate structural column of Example 2 of the present application;

[0031] Figure 5 This is a structural schematic diagram of a pressure-limiting overflow assembly at an external wall of Example 2 of the present application;

[0032] Figure 6 Schematic diagram of the cross-sectional structure of the hydrophobic groove of Example 2 of the present application;

[0033] Description of reference numerals:

[0034] 1. Superstructure; 2. Pile foundation; 3. Drain ditch; 4. Permeable pipe; 5. Drain pipe; 6. Pressure limiting pipe; 7. Overflow elbow; 8. Drain pipe; 9. Sump; 10. Structural column; 11. Cushion; 13. External wall; 14. Emergency pressure relief valve; 15. Closed loop; 16. Elbow; 17. Geotextile; 18. Hydrophobic gravel; 19. Water-proof membrane; 20. Foundation slab. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use.

[0036] Example 1

[0037] The invention discloses an active and passive combined anti-floating device based on pressure-limited overflow, comprising a base plate 20, which is connected to the foundation through a pile foundation 2, a plurality of structural columns 10 are arranged on the base plate 20, and the number of the structural columns 10 can be set as required, a cushion layer 11 is arranged below the base plate 20, a plurality of drainage ditches 3 are arranged in the foundation below the cushion layer 11, a permeable pipe 4 is arranged in the drainage ditches 3, and a pressure-limited overflow component is also included, the pressure-limited overflow component comprises a pressure-limiting pipe 6, the pressure-limiting pipe 6 is arranged in the structural column 10, the permeable pipe 4 penetrates into the structural column 10 through the drainage pipe 5 and is connected to the water inlet end of the pressure-limiting pipe 6, the water outlet end of the pressure-limiting pipe 6 extends out of the structural column 10, the water outlet end of the pressure-limiting pipe 6 is connected to the overflow elbow 7, there is a height difference between the inlet and outlet of the pressure-limiting pipe 6, and the overflow elbow 7 is connected to the sump 9 through the drainage pipe 8.

[0038] The top of the structural column 10 is generally connected to the superstructure 1. It should be noted that the superstructure 1 may be a building or a roof (when there is no building on the upper floor).

[0039] The anti-floating method of the active and passive combined anti-floating device based on pressure-limited overflow comprises the following steps:

[0040] S1, determine the anti-buoyancy bearing capacity of the passive measures according to the deadweight of all buildings above the pile foundation and the anti-buoyancy of the pile foundation 2, and thereby define the pressure limiting water level, which is the setting height of the pressure limiting pipe 6;

[0041] All buildings above the pile foundation include the part above the pile foundation in the anti-floating device of the present application (cushion, foundation slab, structural columns, exterior walls), and also include superstructures.

[0042] The design method of the pressure limiting pipe height is as follows: the self-weight of all buildings above the pile foundation is recorded as G, the anti-buoyancy provided by the pile foundation is recorded as P, and the anti-buoyancy bearing capacity is F=G+P;

[0043] The area of ​​the foundation slab is recorded as A, and the water density is recorded as , then the limit water pressure .

[0044] S2, constructing a pile foundation 2 in the foundation; digging a drainage ditch 3, and laying a permeable pipe 4 in the drainage ditch 3, and connecting the permeable pipe 4 with the drainage pipe 5;

[0045] S3, pouring the cushion layer 11 and the foundation slab 20 in sequence above the drainage ditch 3; connecting the drainage pipe 5 with the pressure limiting pipe 6 when constructing the foundation slab 20;

[0046] S4, constructing a structural column 10 on the foundation slab 20, pouring the lower part of the pressure limiting tube 6 into the structural column 10, and then extending the upper end of the pressure limiting tube 6 out of the structural column 10;

[0047] S5, the overflow elbow 7 is connected to the top of the pressure limiting pipe 6, and the overflow elbow 7 is connected to the drain pipe 8 and then connected to the sump 9;

[0048] S6. When in use, when the groundwater level is lower than the pressure-limiting water level, the pressure-limiting overflow component does not work, and the passive measures composed of the pile foundation 2 and the deadweight of all buildings resist the buoyancy under the actual water level; when the groundwater level is higher than the pressure-limiting water level, the pressure-limiting overflow component starts, and the groundwater infiltrates into the permeable pipe 4 under the pressure difference caused by the water level height of the inlet and outlet, and is discharged through the pressure-limiting pipe 6 and the overflow elbow 7, and the groundwater above the water level is discharged to the sump 9; at the same time, the passive measures continue to resist the buoyancy below the pressure-limiting water level. This application does not require the participation of human or external forces, and can achieve active and passive combined anti-floating, so that the building can effectively cope with the severe test brought by unpredictable weather.

[0049] Example 2

[0050] like Figure 1-Figure 5 As shown, the difference between this embodiment and the first embodiment is that the foundation slab 20 is connected to the outer periphery of the upper building 1 through the outer wall 13, the structural column 10 is located on the foundation slab 20 in the outer wall 13 and between the outer walls 13, the structural column 10 is arranged in a vertical and horizontal cross arrangement, the drainage ditch 3 is also arranged in a vertical and horizontal cross arrangement in the outer wall 13, the drainage ditch 3 located between two structural columns 10 is arranged at the mid-span position of the structural columns 10 on both sides thereof, the drainage ditch 3 can be arranged between every two adjacent rows of structural columns 10, or can be arranged at intervals of several rows of structural columns 10, and the distance between two adjacent drainage ditches 3 in the same direction does not exceed 20 meters. The drainage ditches 3 are connected, and the corresponding permeable pipes 4 are also connected.

[0051] Taking into account that the self-weight stress of the underground structure of one floor is about 20Kpa (can withstand a water head of 2m), the vertical height of the pressure-limiting pipe in the structural column is designed to be ≤1.5m. Based on this vertical height + the thickness of the bottom plate, the emergency pressure head is within 2 meters, which can ensure that the building will not float up even in extreme cases.

[0052] A drainage ditch 3 is also arranged between the outer wall 13 (on which a structural column 10 is also arranged) and the inner adjacent structural column 10. The drainage ditch 3 between the outer wall 13 and the inner adjacent structural column 10 forms a closed loop 15, and the closed loop 15 is also connected with other drainage ditches 3. The pressure limiting pipe 6 can also be arranged on the structural column 10 in the outer wall 13. The number of pressure limiting overflow components can also be set as needed, and the pressure limiting pipe 6 can be arranged on only one structural column 10, or on multiple columns.

[0053] The pressure limiting pipe 6 is provided with an emergency pressure relief valve 14, which can release the pressure in an emergency to avoid floating accidents.

[0054] A water-blocking membrane 19 is provided above the drainage ditch 3, and the water-blocking membrane 19 is connected to the cushion layer 11, and the width of the water-blocking membrane 19 is greater than the width of the top surface of the drainage ditch 3. The width of the water-blocking membrane 19 on both sides of the drainage ditch 3 should be no less than 1 meter, so as to effectively prevent cement slurry from flowing into the drainage ditch when the cushion layer is poured above.

[0055] The cross section of the drainage ditch 3 is a trapezoid, the width of the top surface of the drainage ditch 3 is greater than the width of the bottom surface, and a water-filtering geotextile 17 is laid around the drainage ditch 3. The water-filtering geotextile 17 is filled with hydrophobic gravel 18. The hydrophobic gravel 18 is arranged on the outer periphery of the permeable pipe 4, and the top of the hydrophobic gravel 18 is overlapped and wrapped with the water-filtering geotextile 17. During the layout, the water-filtering geotextile 17 is laid in the drainage ditch 3, the hydrophobic gravel 18 is filled, the permeable pipe 4 is buried, and then the plastic waterproof film 19 is arranged, and the cushion layer 11 and the foundation bottom plate 20 are poured above the plastic waterproof film 19. Groundwater infiltrates into the drainage ditch 3 and is filtered by the water-filtering geotextile 17 and the hydrophobic gravel 18, ensuring smooth flow of liquid in the subsequent pipe to avoid blockage.

[0056] The permeable pipe 4 is provided with a seepage hole, and the drainage ditch 3 is connected to the water flow inside the permeable pipe 4 through the seepage hole. o The elbow 16 is connected to the pressure limiting pipe 6, and the upper part of the limit pipe is also connected by two 135 o The elbow 16 is led out of the structural column 10, so as to facilitate the smooth flow of water;

[0057] The overflow elbow 7 includes a horizontal section and a vertical section connected in sequence. The horizontal section is vertically connected to the outlet end of the pressure limiting pipe 6, and the vertical section is connected to the drain pipe, so that the water flow direction in the vertical section is opposite to the water flow direction in the hydraulic pipe 6. The height of the vertical section is not less than 0.3 meters, thereby effectively preventing water from flowing between the outlets of different pressure limiting pipes and directly discharging it from the overflow elbow.

[0058] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0059] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. Active and passive combined anti-floating device based on pressure-limited overflow, characterized in that: It includes a foundation base plate, which is connected to the foundation through a pile foundation, a plurality of structural columns are arranged on the foundation base plate, a cushion layer is arranged under the foundation base plate, a plurality of drainage ditches are arranged in the foundation under the cushion layer, a permeable pipe is arranged in the drainage ditches, and also includes a pressure limiting overflow component, the pressure limiting overflow component includes a pressure limiting pipe, the pressure limiting pipe is arranged in the structural column, the permeable pipe penetrates into the structural column through the drainage pipe and is connected to the water inlet end of the pressure limiting pipe, the water outlet end of the pressure limiting pipe extends out of the structural column, the water outlet end of the pressure limiting pipe is connected to an overflow elbow, there is a height difference between the inlet and outlet of the pressure limiting pipe, and the overflow elbow is connected to the sump through a drainage pipe.

2. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 1 is characterized in that: The plurality of drainage ditches are arranged in a cross-sectional manner, the plurality of drainage ditches are connected, the corresponding plurality of water-permeable pipes are connected, and the drainage ditches are arranged at the mid-span position of the structural columns on both sides thereof.

3. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 1 is characterized in that: An outer wall is arranged on the foundation bottom plate, and structural columns are arranged inside the outer wall. A drainage ditch is arranged between the outer wall and its inner adjacent structural columns, and the drainage ditch between the outer wall and its inner adjacent structural columns forms a closed loop.

4. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 1 is characterized in that: The pressure limiting pipe is provided with an emergency pressure relief valve.

5. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 1 is characterized in that: The permeable pipe is provided with a seepage hole, and the drainage ditch introduces the water in the drainage ditch into the permeable pipe through the seepage hole.

6. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 1 is characterized in that: The cross section of the drainage ditch is trapezoidal, the width of the top surface of the drainage ditch is greater than the width of the bottom surface, a water-filtration geotextile is laid around the drainage ditch, the water-filtration geotextile is filled with hydrophobic gravel, a permeable pipe is buried in the hydrophobic gravel, and the top of the hydrophobic gravel is wrapped with a water-filtration geotextile.

7. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 1 is characterized in that: A water-isolating membrane is arranged above the hydrophobic groove, the water-isolating membrane is connected to the cushion layer, and the width of the water-isolating membrane is greater than the width of the top surface of the hydrophobic groove.

8. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 1 is characterized in that: The overflow elbow comprises a horizontal section and a vertical section connected in sequence, the horizontal section is vertically connected to the outlet end of the pressure limiting pipe, the vertical section is connected to the drain pipe, and the height of the vertical section is not less than 0.3 meters.

9. The active and passive combined anti-floating device based on pressure-limited overflow according to claim 7 is characterized in that: The width of the water-blocking membrane on both sides of the drainage ditch shall not be less than 1 meter.

10. The anti-floating method of the active and passive combined anti-floating device based on pressure-limited overflow according to any one of claims 1 to 9, characterized in that: The steps include: S1. Determine the anti-buoyancy bearing capacity of passive measures based on the deadweight of all buildings above the pile foundation and the anti-buoyancy of the pile foundation, and define the pressure limit water level accordingly. The pressure limit water level is the installation height of the pressure limit pipe; S2. construct a pile foundation in the foundation; dig a drainage ditch, lay a permeable pipe in the drainage ditch, and connect the permeable pipe with the drainage pipe; S3. Cast the cushion layer and the foundation slab in sequence above the drainage ditch; connect the drainage pipe with the pressure limiting pipe when constructing the foundation slab; S4. construct a structural column on the foundation slab, cast the lower part of the pressure limiting pipe in the structural column, and then extend the upper end of the pressure limiting pipe out of the structural column; S5. Connect the overflow elbow at the top of the pressure limiting pipe, and the overflow elbow is connected to the drainage pipe and then connected to the sump; S6. During use, when the groundwater level is lower than the pressure-limiting water level, the pressure-limiting overflow assembly does not work, and the passive measures consisting of the pile foundation and the deadweight of all buildings resist the buoyancy under the actual water level; when the groundwater level is higher than the pressure-limiting water level, the pressure-limiting overflow assembly starts, and the groundwater seeps into the permeable pipe under the action of water pressure, and is discharged through the pressure-limiting pipe and the overflow elbow, and the groundwater above the water level is discharged into the sump; at the same time, the passive measures continue to resist the buoyancy below the pressure-limiting water level, that is, active and passive combined anti-buoyancy.

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