Multi-stage vacuum drainage construction method for pit-in-pit
Through the multi-stage vacuum drainage construction method, using vacuum pumps and water collection tank systems, the problems of sediment loss and equipment damage in pit-in-pit drainage are solved, efficient and environmentally friendly foundation pit drainage is achieved, and construction costs and maintenance difficulties are reduced.
Patent Information
- Application Number
- CN202510879802.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-27
- Publication Date
- 2025-09-23
AI Technical Summary
The existing pit-in-pit drainage method has problems such as sediment loss, slope landslide, precipitation affecting foundation construction, well sealing affecting anti-seepage function, and increased cost of equipment and facilities disposal, which leads to increased difficulty and cost of foundation pit dewatering and does not meet the requirements of environmental protection, energy conservation and green construction.
A multi-stage vacuum drainage construction method is adopted. By installing a vacuum pump, a vacuum tank and a water collecting tank in each layer of the foundation pit, the vacuum pump is used to adjust the pressure of the water collecting tank. Combined with the water absorption structure and flocculant stirring, multi-stage foundation pit mud and water separation and automatic slag removal are achieved, avoiding submersible sewage pumps and temporary electricity use, and simplifying the maintenance process.
It achieves efficient drainage of multi-level foundation pits, avoids silt blockage and equipment damage, reduces construction costs, meets environmental protection and energy-saving requirements, and simplifies repair and maintenance work.
Smart Images
Figure CN120683877A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of building construction, and in particular to a multi-stage vacuum drainage construction method for a pit within a pit. Background Art
[0002] With the rapid development of the construction market, more and more super-high-rise buildings are rising from the ground, and the excavation depth of foundation pits is getting deeper and deeper. Pit-in-pit drainage has become a common phenomenon. In coastal areas, the rainy season is long and the rainfall is heavy. A large amount of surface water flows into the foundation pit, and the groundwater is also extremely abundant, which affects the smooth progress of underground projects. Water blocking and water retaining cofferdams cannot achieve ideal results. Usually, open ditch drainage method is required, but this method has serious disadvantages of sediment loss and slope collapse.
[0003] Existing patented technologies also have many problems that are not in line with environmental protection, energy conservation and green construction, such as dewatering affecting foundation construction, sealing wells affecting anti-seepage functions, and discarding equipment and facilities seriously increasing costs. These problems have led to increasing difficulty and cost in foundation pit dewatering. Summary of the Invention
[0004] In order to improve the existing pit-in-pit drainage, which requires the installation of submersible sewage pumps and temporary electricity connection in each foundation pit, thus affecting the foundation construction, the present application provides a multi-stage vacuum drainage construction method for pit-in-pit.
[0005] The present application provides a multi-stage vacuum drainage construction method for a pit within a pit, which adopts the following technical solutions: A multi-stage vacuum drainage construction method for a pit-in-pit, comprising the following steps: S1. Be familiar with the geological survey report and drawings, analyze the relevant geological conditions and water level of the pit-in-pit location, and ensure that the height difference of each foundation pit layer does not exceed 7 meters based on the geology and water level of the pit-in-pit; S2. After each foundation pit is constructed, the bottom plate should be sloped as required and a drainage ditch should be set around the perimeter. S3. A vacuum pump, vacuum tank, and first water collection tank are installed on the ground floor. A second water collection tank connected to the first water collection tank is installed on the first floor below ground level. Drain pipes are used to connect the pipes. Solenoid valves are installed at each joint of the drainage pipes. A water absorption structure connected to the second water collection tank is installed in the water collection pits on the first and second floors below ground level. S4. Start the vacuum pump to evacuate the vacuum tank; S5. Open the solenoid valves between the first water collecting tank and the vacuum tank and between the first water collecting tank and the second water collecting tank, reduce the air pressure in the second water collecting tank to -0.05 to -0.07 MPa, and then open the solenoid valve between the second water collecting tank and the water absorption structure; S6. The sewage pumped into the second water collection tank is allowed to settle, and the supernatant is pumped into the first water collection tank; S7. Adjust the first water collecting tank to normal pressure and drain the water into the drainage ditch.
[0006] Furthermore, the water absorbing structure in step S3 includes: Spring hose, connected to the end of the drain pipe; a pipeline float connected to the bottom end of the spring hose; The water suction cylinder has a closed bottom end and an open top end and is communicated with the pipeline float. A plurality of water suction holes are opened on the outer peripheral wall of the water suction cylinder.
[0007] Furthermore, the outer peripheral wall of the water suction cylinder is covered with wire mesh at intervals.
[0008] Furthermore, a mixing tank is connected to the drainage pipe connected to the water absorption structure of the second water collecting tank. The mixing tank is provided with an agitator and a dosing box for adding flocculant to the mixing tank.
[0009] Furthermore, a sewage pipe is provided at the bottom of the second water collecting tank, a sewage valve is provided on the sewage pipe, and a slag removal box is provided below the second water collecting tank.
[0010] Furthermore, a liquid level sensor is provided in the second water collecting tank, and a weighing sensor is provided outside the second water collecting tank, and both the liquid level sensor and the weighing sensor are controllably connected to the sewage valve; When the net weight of the sewage in the second water collecting tank detected by the weighing sensor exceeds 30% of the total weight of the volume of water corresponding to the liquid level detected by the liquid level sensor, the sewage valve is controlled to open; When the net weight of the sewage in the second water collecting tank detected by the weighing sensor is close to the total weight of the volume of water corresponding to the liquid level detected by the liquid level sensor, the sewage valve is controlled to close.
[0011] Furthermore, a slag discharge port connected to the sewage pipe is provided at the bottom of the second water collecting tank, and a guide slope docking with the slag discharge port is provided on the inner bottom wall of the second water collecting tank, and the side of the guide slope close to the slag discharge port is the lower end.
[0012] Furthermore, both the first water collecting tank and the second water collecting tank are provided with a vent valve.
[0013] Furthermore, a slope plate is provided on the inner bottom wall of the first water collecting tank, and the lower end of the slope plate is close to the drainage ditch.
[0014] Furthermore, a fixing clip is fixedly connected to the outer peripheral wall of the drain pipe connected to the spring hose, and the drain pipe is suspended and fixed on the sump manhole cover through the fixing clip.
[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. By installing a vacuum pump on the ground floor of the site, using a vacuum tank to connect and adjust the internal pressure of each water collection tank, and connecting the water collection tank to the water absorption structure through a drainage pipe, muddy water from each foundation pit layer can be collected and discharged. This can meet the requirements of multi-level foundation pit relay drainage, avoid the disadvantages of the traditional method of installing a submersible sewage pump and pulling temporary electricity in each foundation pit collection pit, and has the characteristics of easy repair and maintenance; 2. The arrangement of the pipe float and spring hose in the water absorption structure ensures that the water absorption cylinder is always submerged below the liquid level in the sump, while the corresponding drainage pipe is always above the liquid level. The positions of the two are dynamically adjusted as the liquid level in the sump changes. This overcomes the defect of the bottom drainage method where the water absorption port is easily blocked by debris and dirt, thus affecting drainage efficiency. In addition, the water absorption structure can be raised and lowered as the liquid level changes. 3. The addition of flocculants and rapid stirring by adding a dosing box in the drainage pipe and the filtration and slag removal method at the bottom of the water collecting tank can avoid the accumulation of sediment inside the equipment and damage to the equipment, and achieve rapid sewage sedimentation and mud-water separation. 4. By setting a weighing sensor on the base of the water tank and using a liquid level sensor to detect the liquid level in the second water collecting tank, and then based on the weight difference of the same volume of sewage containing sediment and clean water, the mud content in the water can be judged by the weight change of the net weight of the liquid in the second water collecting tank. Then, according to the opening and closing control logic of the sewage valve, the opening of the sewage valve is controlled, or the sewage valve is started at a fixed time to clean the sediment at the bottom of the tank, avoiding the inconvenience of manual cleaning and realizing the automatic slag removal function of the system. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0017] Figure 1 This is a schematic diagram of the system structure of an embodiment of the present application; Figure 2 This is a schematic diagram of the system structure layout of the embodiment of the present application; Figure 3 Schematic diagram of the structure of the water absorption structure of the embodiment of the present application; Figure 4 This is a simplified structural diagram of the mixing tank, agitator, and dosing box of an embodiment of the present application; Figure 5 This is a simplified structural diagram of the second water collecting tank and related components of an embodiment of the present application.
[0018] Reference numerals: 1. Drainage ditch; 21. Vacuum pump; 22. Vacuum tank; 31. First water collecting tank; 311. Slope plate; 32. Second water collecting tank; 33. Vent valve; 41. Spring hose; 42. Pipe float; 43. Water suction cylinder; 44. Wire mesh; 45. Fixing clip; 51. Mixing tank; 52. Agitator; 53. Dosing box; 61. Drain pipe; 62. Drain valve; 63. Slag removal box; 64. Slag discharge port; 65. Guide slope; 71. Liquid level sensor; 72. Weighing sensor; 81. First solenoid valve; 82. Second solenoid valve; 83. Third solenoid valve; 84. Fourth solenoid valve; 85. Fifth solenoid valve. DETAILED DESCRIPTION
[0019] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0020] Reference Figure 1 The present invention discloses a multi-stage vacuum drainage construction method for a pit-in-pit, which comprises the following steps: S1. Be familiar with the geological survey report and drawings, analyze the relevant geological conditions and water level of the location of the pit within the pit, and ensure that the height difference of each layer of the foundation pit does not exceed 7 meters based on the geology and water level of the pit within the pit.
[0021] S2. After the construction of each foundation pit, the bottom plate is sloped as required, and a 300×300mm drainage ditch 1 is set around the perimeter to ensure that it can intercept water during rainfall. The accumulated water in the drainage ditch 1 will eventually converge into the collection pit of that layer.
[0022] S3. A vacuum pump 21, a vacuum tank 22, and a first water collection tank 31 are installed on the ground floor. A second water collection tank 32 connected to the first water collection tank 31 is installed on the basement level. Drain pipes are used to connect all pipes, and solenoid valves are installed at each joint of the drain pipes. Water absorption structures connected to the second water collection tank 32 are installed in the basement level and basement level 2 water collection pits. Specifically, a first solenoid valve 81 is installed between the vacuum tank 22 and the first water collection tank 31, a second solenoid valve 82 is installed at the drain outlet of the first water collection tank 31, a third solenoid valve 83 is installed between the first water collection tank 31 and the second water collection tank 32, a fourth solenoid valve 84 is installed between the second water collection tank 32 and the water absorption structure in the basement level 1 water collection pit, and a fifth solenoid valve 85 is installed between the second water collection tank 32 and the water absorption structure in the basement level 2 water collection pit.
[0023] S4. During operation, the first electromagnetic valve 81 is first closed, and the vacuum pump 21 is started to evacuate the vacuum tank 22 until the air pressure in the vacuum tank 22 is between -30 kPa and -70 kPa.
[0024] S5. When draining the basement level 2 sump pit is necessary, the first and third solenoid valves 81 and 83 are opened to reduce the pressure in the second header tank 32 to -0.05 to -0.07 MPa. The fifth solenoid valve 85 is then opened to pump out the water from the basement level 2 sump pit. If draining the basement level 1 sump pit is necessary, the fourth solenoid valve 84 is opened to pump out the water from the basement level 1 sump pit after the pressure in the second header tank 32 drops to the set value.
[0025] S6. The sewage pumped into the second water collecting tank 32 is allowed to settle. After the mud and water are separated, the first solenoid valve 81 and the third solenoid valve 83 can be opened to pump the supernatant in the second water collecting tank 32 into the first water collecting tank 31. Specifically, the supernatant in the second water collecting tank 32 is pumped out after the sediment in the second clean water tank is discharged.
[0026] S7. Adjust the first water collecting tank 31 to normal pressure, open the second solenoid valve 82 and drain the water to the drainage ditch 1.
[0027] The water absorbing structure in step S3 includes: The spring hose 41 is connected to the end of the drain pipe extending into the sump, and a fixing clamp 45 is fixed to the outer peripheral wall of the drain pipe connected to the spring hose 41. The drain pipe is suspended and fixed on the sump manhole cover through the fixing clamp 45.
[0028] The pipeline float 42 is connected to the bottom end of the spring hose 41 and is specifically hollow.
[0029] The water suction cylinder 43 has a closed bottom end and an open top end and is connected to the pipeline float 42. A plurality of water suction holes are opened on the outer peripheral wall of the water suction cylinder 43, and the outer peripheral wall of the water suction cylinder 43 is covered with diamond-shaped wire mesh 44 at intervals.
[0030] In addition, a sealed stirring tank 51 is connected to the drainage pipe connected to the water absorption structure of the second water collecting tank 32 . The stirring tank 51 is provided with an agitator 52 and a dosing box 53 for adding flocculant to the stirring tank 51 .
[0031] Furthermore, a sewage pipe 61 is provided at the bottom of the second water collecting tank 32, on which a sewage valve 62 is provided. A slag removal box 63 is provided below the second water collecting tank 32. A slag discharge port 64 connected to the sewage pipe 61 is provided at the bottom of the second water collecting tank 32. A guide slope 65 is provided on the inner bottom wall of the second water collecting tank 32, which interfaces with the slag discharge port 64. The side of the guide slope 65 closest to the slag discharge port 64 is the lower end. A liquid level sensor 71 is provided inside the second water collecting tank 32, and a weighing sensor 72 is provided outside the second water collecting tank 32. The second water collecting tank 32 is installed on the foundation pit water tank foundation via the weighing sensor 72. Both the liquid level sensor 71 and the weighing sensor 72 are controlled and connected to the sewage valve 62. The specific control logic is as follows: When the net weight of sewage in the second water collecting tank 32 detected by the weighing sensor 72 exceeds 30% of the total weight of the volume of water corresponding to the liquid level detected by the liquid level sensor 71, the sewage valve 62 is controlled to open; When the net weight of the sewage in the second water collecting tank 32 detected by the weighing sensor 72 is close to the total weight of the volume of water corresponding to the liquid level detected by the liquid level sensor 71, the sewage valve 62 is controlled to close.
[0032] In addition, refer to Figure 1 and Figure 2 The first and second water collecting tanks 31, 32 are both provided with vent valves 33 to adjust the air pressure in the first and second water collecting tanks 31, 32. A slope plate 311 is provided on the bottom wall of the first water collecting tank 31, with the lower end of the slope plate 311 close to the drainage ditch 1 to ensure that the water at the bottom of the tank flows to one place for discharge.
[0033] Therefore, by setting up a vacuum pump 21 on the first floor plane on site, using the vacuum tank 22 to connect and adjust the internal pressure of each water collecting tank, the second water collecting tank 32 is connected to the water absorption structure through the drainage pipe, which can collect mud and water from each layer of the foundation pit and then discharge it; it can meet the requirements of multi-level foundation pit relay drainage, avoid the disadvantages of installing a submersible sewage pump and pulling temporary electricity in each layer of the foundation pit collection pit under the traditional method, and has the characteristics of easy repair and maintenance.
[0034] Moreover, by setting up the pipe float 42 and the spring hose 41 in the water absorption structure, it can be ensured that the water absorption cylinder 43 can always be immersed below the liquid surface of the sump, while the corresponding drainage pipe is always above the liquid surface, and the positions of the two are dynamically adjusted with the changes in the liquid level in the sump, which can overcome the defect that the water absorption port is easily blocked by debris and dirt under the bottom drainage method, thereby affecting the drainage efficiency, and can also meet the function of the water absorption structure being able to rise and fall with the changes in the liquid level.
[0035] In addition, by installing a dosing box 53 in the drain pipe to add flocculants and perform rapid stirring, and by providing a water filtration and deslagging system at the bottom of the water collection tank, the equipment can be prevented from silt accumulation and sedimentation inside the equipment, which could damage the equipment, thereby achieving rapid sewage sedimentation and mud-water separation. Furthermore, by installing a weighing sensor 72 at the base of the water tank and using a liquid level sensor 71 to detect the liquid level in the second water collection tank 32, the weight difference between the same volume of sewage containing sediment and clean water can be used to determine the mud content in the water by the change in the net weight of the liquid in the second water collection tank 32. The drain valve 62 can then be opened or activated periodically based on its opening and closing control logic to clean the sediment at the bottom of the tank, eliminating the inconvenience of manual cleaning and achieving the system's automatic deslagging function.
[0036] The implementation principle of a multi-stage vacuum drainage construction method for a pit in a pit in the present application is as follows: By setting up a vacuum pump 21 on the first floor plane on site, using the vacuum tank 22 to connect and adjust the internal pressure of each water collecting tank, the second water collecting tank 32 is connected to the water absorption structure through the drainage pipe, which can collect mud and water from each layer of the foundation pit and then discharge it; it can meet the requirements of multi-level foundation pit relay drainage, avoid the disadvantages of installing a submersible sewage pump and pulling temporary electricity in each layer of the foundation pit collection pit under the traditional method, and has the characteristics of easy repair and maintenance.
[0037] After the sewage in the sump is pumped out to the second collecting tank 32, a weighing sensor 72 is set on the base of the water tank, and the liquid level in the second collecting tank 32 is detected with the help of a liquid level sensor 71. Then, according to the weight difference of the same volume of sewage containing sediment and clean water, the mud content in the water can be judged by the weight change of the net weight of the liquid in the second collecting tank 32. Then, the opening of the sewage valve 62 is controlled according to the opening and closing control logic of the sewage valve 62, or the sewage valve 62 is started at a fixed time to clean the sediment at the bottom of the tank, thereby avoiding the inconvenience of manual cleaning and realizing the automatic slag removal function of the system.
[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.
Claims
1. A multi-stage vacuum drainage construction method for a pit in a pit, characterized in that: The following steps are involved: S1. Be familiar with the geological survey report and drawings, analyze the relevant geological conditions and water level of the pit-in-pit location, and ensure that the height difference of each foundation pit layer does not exceed 7 meters based on the geology and water level of the pit-in-pit; S2. After each foundation pit is constructed, the bottom plate should be sloped as required and a drainage ditch should be set around the perimeter. S3. A vacuum pump, vacuum tank, and first water collection tank are installed on the ground floor. A second water collection tank connected to the first water collection tank is installed on the first floor below ground level. Drain pipes are used to connect the pipes. Solenoid valves are installed at each joint of the drainage pipes. A water absorption structure connected to the second water collection tank is installed in the water collection pits on the first and second floors below ground level. S4. Start the vacuum pump to evacuate the vacuum tank; S5. Open the solenoid valves between the first water collecting tank and the vacuum tank and between the first water collecting tank and the second water collecting tank, reduce the air pressure in the second water collecting tank to -0.05 to -0.07 MPa, and then open the solenoid valve between the second water collecting tank and the water absorption structure; S6. The sewage pumped into the second water collection tank is allowed to settle, and the supernatant is pumped into the first water collection tank; S7. Adjust the first water collecting tank to normal pressure and drain the water into the drainage ditch.
2. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 1, characterized in that: The water absorbing structure in step S3 includes: Spring hose, connected to the end of the drain pipe; a pipeline float connected to the bottom end of the spring hose; The water suction cylinder has a closed bottom end and an open top end and is communicated with the pipeline float. A plurality of water suction holes are opened on the outer peripheral wall of the water suction cylinder.
3. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 2, characterized in that: The outer peripheral wall of the water suction cylinder is covered with wire mesh at intervals.
4. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 1, characterized in that: The drainage pipe connecting the second water collecting tank and the water absorption structure is connected to a stirring tank, and the stirring tank is provided with a stirrer and a dosing box for adding flocculant to the stirring tank.
5. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 1, characterized in that: A sewage pipe is provided at the bottom of the second water collecting tank, a sewage valve is provided on the sewage pipe, and a slag removal box is provided below the second water collecting tank.
6. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 5, characterized in that: A liquid level sensor is provided inside the second water collecting tank, and a weighing sensor is provided outside the second water collecting tank, and both the liquid level sensor and the weighing sensor are controllably connected to the sewage valve; When the net weight of the sewage in the second water collecting tank detected by the weighing sensor exceeds 30% of the total weight of the volume of water corresponding to the liquid level detected by the liquid level sensor, the sewage valve is controlled to open; When the net weight of the sewage in the second water collecting tank detected by the weighing sensor is close to the total weight of the volume of water corresponding to the liquid level detected by the liquid level sensor, the sewage valve is controlled to close.
7. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 6, characterized in that: The bottom of the second water collecting tank is provided with a slag discharge port connected to the sewage pipe, and the inner bottom wall of the second water collecting tank is provided with a guide slope docking with the slag discharge port, and the side of the guide slope close to the slag discharge port is the lower end.
8. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 1, characterized in that: The first water collecting tank and the second water collecting tank are both provided with a vent valve.
9. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 1, characterized in that: The inner bottom wall of the first water collecting tank is provided with a slope plate, and the lower end of the slope plate is close to the drainage ditch.
10. The multi-stage vacuum drainage construction method for a pit in a pit according to claim 2, characterized in that: A fixing clip is fixedly connected to the outer peripheral wall of the drainage pipe connected to the spring hose, and the drainage pipe is suspended and fixed on the sump manhole cover through the fixing clip.