CN115162388B - Foundation pit parallel siphon dewatering device and dewatering construction method - Google Patents
Foundation pit parallel siphon dewatering device and dewatering construction method Download PDFInfo
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- CN115162388B CN115162388B CN202210962959.8A CN202210962959A CN115162388B CN 115162388 B CN115162388 B CN 115162388B CN 202210962959 A CN202210962959 A CN 202210962959A CN 115162388 B CN115162388 B CN 115162388B
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- 238000010276 construction Methods 0.000 title claims abstract description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 398
- 238000002347 injection Methods 0.000 claims abstract description 71
- 239000007924 injection Substances 0.000 claims abstract description 71
- 238000000034 method Methods 0.000 claims abstract description 34
- 230000008569 process Effects 0.000 claims abstract description 33
- 238000001914 filtration Methods 0.000 claims abstract description 11
- 238000001556 precipitation Methods 0.000 claims description 68
- 239000007788 liquid Substances 0.000 claims description 20
- 230000001276 controlling effect Effects 0.000 claims description 18
- 238000007599 discharging Methods 0.000 claims description 7
- 239000012530 fluid Substances 0.000 claims description 6
- 230000007246 mechanism Effects 0.000 claims description 6
- 230000001105 regulatory effect Effects 0.000 claims description 5
- 238000004140 cleaning Methods 0.000 claims description 4
- 238000013461 design Methods 0.000 claims description 4
- 238000005086 pumping Methods 0.000 claims description 3
- 238000004064 recycling Methods 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 16
- 239000002689 soil Substances 0.000 abstract description 6
- 238000012544 monitoring process Methods 0.000 abstract description 4
- 238000009412 basement excavation Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000013049 sediment Substances 0.000 description 4
- 238000011161 development Methods 0.000 description 3
- 230000000149 penetrating effect Effects 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000009825 accumulation Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 238000013022 venting Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000003673 groundwater Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D19/00—Keeping dry foundation sites or other areas in the ground
- E02D19/06—Restraining of underground water
- E02D19/10—Restraining of underground water by lowering level of ground water
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D29/00—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor
- B01D29/50—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition
- B01D29/52—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in parallel connection
- B01D29/54—Filters with filtering elements stationary during filtration, e.g. pressure or suction filters, not covered by groups B01D24/00 - B01D27/00; Filtering elements therefor with multiple filtering elements, characterised by their mutual disposition in parallel connection arranged concentrically or coaxially
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04F—PUMPING OF FLUID BY DIRECT CONTACT OF ANOTHER FLUID OR BY USING INERTIA OF FLUID TO BE PUMPED; SIPHONS
- F04F10/00—Siphons
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- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Hydrology & Water Resources (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Structural Engineering (AREA)
- Mechanical Engineering (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
Abstract
The invention discloses a foundation pit parallel siphon dewatering device and a dewatering construction method, and belongs to the field of foundation pit engineering construction. The basic component of the foundation pit parallel siphon dewatering device comprises a water collecting well, a siphon pipe network, a drainage device, a water injection and exhaust device and a gas collecting tank, and is used for synchronously dewatering a plurality of dewatering wells in the foundation pit. The siphon dewatering device utilizes the water level difference to siphon dewatering, has stable water flow, can reduce soil loss in the dewatering process, is provided with the filter at the end part of the siphon branch pipe, adopts a denser filter screen, has better filtering effect and can be cleaned and replaced. The invention can treat the drainage of a plurality of dewatering wells simultaneously, only one water pump is needed to be arranged in the water collecting well as power, and the water level elevation of each dewatering well is similar due to the siphon effect. Therefore, the invention can achieve the effect of controlling a plurality of dewatering wells simultaneously by controlling one water pump and monitoring the water level of one dewatering well, reduces the complexity of dewatering control, saves cost and has easy control of the water level.
Description
Technical Field
The invention belongs to the field of construction devices, and particularly relates to a foundation pit parallel siphon dewatering device and a dewatering construction method.
Background
With the development of urban areas, underground space development is more and more, and foundation pit dewatering is often involved in the underground space development process. The foundation pit dewatering mode commonly used at present is pipe well dewatering. The dewatering of the pipe well is achieved by digging the well inside and outside the foundation pit, placing the well pipe and the filter in the well, and then placing the water pump into the well pipe to pump water, so that the aim of reducing underground water is fulfilled.
The pipe well precipitation has the following problems in the use process: (1) The filter has poor reliability and is easy to damage, and the filter is damaged and is difficult to repair or replace; (2) As the water level changes, the water pump needs to be started and stopped frequently in the dewatering process, when the water pump is started and stopped, larger vortex is generated, fine particles in the soil are easily carried out along with water flow, and soil loss is caused; (3) A water pump is arranged in each precipitation well, the water level of each precipitation well is independent, the control of the precipitation water level in the precipitation process is complex, the workload is large, and the condition of superdrop or underdrop is easy to occur.
Disclosure of Invention
The invention aims to overcome the defects of complex foundation pit dewatering control and low filtering reliability in the prior art, and provides a foundation pit parallel siphon dewatering device and a dewatering construction method.
The specific technical scheme adopted by the invention is as follows:
the invention provides a foundation pit parallel siphon dewatering device, which comprises a water collecting well, a siphon pipe network, a drainage device, a water injection and exhaust device and a gas collecting tank, wherein the water injection and exhaust device and the gas collecting tank are used for synchronously dewatering a plurality of dewatering wells in the foundation pit;
the siphon pipe network comprises a main siphon pipe and a plurality of siphon branch pipes; the siphon main pipe is arranged on the ground of the foundation pit edge where each dewatering well is located, the first end part of the siphon main pipe is connected with the water injection and exhaust device, and the second end part of the siphon main pipe is positioned below the liquid level of the water collecting well after penetrating through the wall of the water collecting well; each siphon branch pipe corresponds to one dewatering well respectively, the first end part of each siphon branch pipe is connected with a siphon main pipe, and the second end part of each siphon branch pipe stretches into the dewatering well and is sequentially connected with a check valve and a filter; the filter is used for carrying out secondary impurity removal and filtration on underground water entering the siphon branch pipe, and the check valve is a one-way valve and is used for controlling water in the siphon branch pipe to flow unidirectionally into the siphon main pipe but not flow reversely into the dewatering well;
the bottom, the top and the side parts of the gas collection tank are respectively provided with an opening, and are respectively provided with a gas inlet bottom valve, a gas outlet top valve and a water injection side valve for controlling the opening to be opened and closed; the gas collection tank is arranged at the position of the siphon main pipe penetrating through the front end of the wall of the water collection well, and the highest water injection liquid level allowed by the water collection well is higher than the top of the gas collection tank; the siphon main pipe between the water injection and exhaust device and the gas collection tank is in inclined arrangement with gradually increased elevation, and the gas collection tank is communicated with the highest elevation position of the siphon main pipe through the bottom opening where the air inlet bottom valve is positioned, so that all the other pipe sections can be collected into the gas collection tank when the air exists;
The water injection and exhaust device is used for injecting water into the siphon main pipe under pressure, and assisting bubbles in the siphon main pipe to be discharged from the second end part or enter the gas collection tank along with high-speed water flow;
the drainage device is used for draining water accumulated in the water collecting well.
According to the technical scheme, the problem that the siphon flow speed or the flow break is affected due to the fact that bubbles at the top of the pipe are easy to accumulate in the siphon operation process is solved, the convenience of water level control in the dewatering process is improved, the workload of water level control is reduced, and meanwhile the occurrence of the condition of over-drop or under-drop is reduced.
As a preferable mode of the first aspect, the water injection and exhaust device includes a pressure water source and a water injection valve, the pressure water source outlet is connected with the first end of the siphon main pipe, and the water injection valve is used for controlling the water path on-off between the pressure water source and the siphon main pipe.
As a preferable aspect of the first aspect, the check valve is a semi-closed check valve, and includes a valve body, a valve plate, a first positioning member, a second positioning member, and a guide rod; the valve plate, the first positioning piece, the second positioning piece and the guide rod are all arranged in the valve body; the first positioning piece and the second positioning piece are arranged on two cross sections in the inner cavity of the valve body in parallel and are respectively positioned on two sides of the valve seat; the guide rod vertically passes through the center of the valve plate and is fixedly connected with the valve plate, and two ends of the guide rod respectively form a sliding pair used for ensuring the guide rod to move along the axial direction with the first positioning piece and the second positioning piece; the valve plate and the valve seat form an opening and closing mechanism guided by a guide rod; when fluid flows from the first valve port to the second valve port, the valve plate is separated from the valve seat, and a valve inner flow passage is opened; when fluid flows from the second valve port to the first valve port, the valve plate is pressed on the valve seat, and the valve inner flow passage is closed; capillary holes with diameters not exceeding 1mm are formed in the valve plate.
As a preferable aspect of the first aspect, the first positioning member and the second positioning member are both water-permeable discs with a guide hole in the center, and two ends of the guide rod respectively penetrate into the two guide holes to form the guide mechanism.
Preferably, the filter comprises a framework and a filter screen, wherein the filter screen is sleeved outside the framework in a surrounding manner, so that a filter structure for wrapping the valve port of the check valve is formed.
As a preferable aspect of the above first aspect, the drainage device includes a water pump, a sump, and a drain; the pump body of the water pump is positioned below the liquid level of the water collecting well, and an output pipe at the outlet of the pump body extends into the water collecting pit connected with the drainage ditch and is used for pumping water collected in the water collecting well into the water collecting pit and discharging the water outside through the drainage ditch.
As a preferred aspect of the first aspect, all dewatering wells in the foundation pit are divided into a plurality of groups, and each group of dewatering wells is provided with a separate siphon network, a water injection and exhaust device and a gas collection tank.
As a preferable aspect of the above first aspect, the screen is a 300 mesh or more screen.
In a second aspect, the present invention provides a construction method for parallel siphon precipitation of a foundation pit based on the device for parallel siphon precipitation of a foundation pit in the first aspect, which includes the following steps:
S1, excavating a dewatering well in a foundation pit to be subjected to dewatering, excavating a water collecting well, a water collecting pit and a drainage ditch outside the foundation pit, and then installing the siphon pipe network, a drainage device, a water injection exhaust device and a gas collecting tank to form the foundation pit parallel siphon dewatering device;
s2, opening an air inlet bottom valve and an air outlet top valve of the air collection tank, and closing a water injection side valve of the air collection tank; injecting water into the water collecting well through an external water source and keeping the water level in the water collecting well higher than the highest point of the siphon main pipe, so that the water in the water collecting well flows into the siphon main pipe and further flows into each siphon branch pipe, and valve plates in check valves at the tail ends of the siphon branch pipes are pressed on the valve seats under the pressure in the pipes, so that the flow paths in the valves are closed; in the water injection process, water in the siphon branch pipe cannot directly flow into the dewatering well, part of original air in the siphon net is driven by water flow to be discharged from a check valve at the bottom end of the siphon branch pipe, and the other part of the air is reversely upwards and is collected in the gas collecting tank through the siphon pipe network and is discharged from an exhaust top valve of the gas collecting tank; when the siphon pipe network is filled with water, the water overflows from the exhaust top valve of the gas collecting tank, at the moment, the exhaust top valve of the gas collecting tank is closed, and the water injection of the siphon pipe network is completed, so that siphons are formed;
S3, after the siphon net is filled with water, starting a water pump in the water collecting well, continuously discharging the water in the water collecting well into the water collecting pit, when the water level of the water collecting well is lower than that of any dewatering well, automatically flowing the water in the corresponding dewatering well into the water collecting well through a siphon principle, and discharging the water in the water collecting pit through a drainage ditch after precipitation;
in the siphon dewatering process, the water level difference between the liquid level in the water collecting well and the liquid level of each dewatering well is regulated by controlling the flow of the water pump, so that the dewatering depth in each dewatering well is controlled to meet the design requirement;
in the siphon dewatering process, an air inlet bottom valve on the air collection tank is initially kept in an open state, and a water injection side valve and an air exhaust top valve are in a closed state, so that bubbles in the pipe are continuously collected into the air collection tank along with the flow of water flow; when the space occupied by air in the air collection tank reaches a set value, closing an air inlet bottom valve of the air collection tank, disconnecting the air collection tank and a siphon pipe network, then opening an air outlet top valve of the air collection tank, and then filling water into the air collection tank through a water filling side valve to replace the internal air; after the water is filled in the gas collecting tank, the water filling side valve and the exhaust top valve are closed, the gas inlet bottom valve is opened again, the gas collecting tank and the siphon pipe network are communicated, and the gas collecting function of the gas collecting tank is recovered;
In the siphon dewatering process, the water injection and exhaust device operates regularly, the flow velocity of water in the siphon main pipe is increased by pressure water, and bubbles which are accumulated at the top of the pipe wall in the siphon main pipe and influence normal operation of the siphon are taken away;
s4, after precipitation is finished, recycling the siphon pipe network, the drainage device, the water injection and exhaust device and the gas collection tank, and backfilling the precipitation well and the water collection well.
As a preferable aspect of the second aspect, when the filter is clogged during siphon precipitation, the filter is taken out for cleaning or replacement, and then the filter is replaced to the original position, and the siphon is restarted S2 to continue siphon precipitation.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention can treat the drainage of a plurality of dewatering wells simultaneously, only one water pump is needed to be arranged in the water collecting well as power, and the water level elevation of each dewatering well is similar due to the siphon effect. Therefore, the invention can achieve the effect of controlling a plurality of dewatering wells simultaneously by controlling one water pump and monitoring the water level of one dewatering well. The complexity of precipitation control is reduced, the labor cost of precipitation and the water level monitoring cost are saved, and the water level is easy to control.
2. The invention only needs to put a siphon branch pipe with smaller diameter into the dewatering well, and the diameter of the dewatering well can be small under the condition that the dewatering well meets the water inlet requirement. The common pipe well is used for dewatering, and the diameter of the dewatering well is larger because a water pump needs to be placed in the pipe well. The diameter of the dewatering well is greatly reduced, and the cost of pore forming, backfilling and the like of the dewatering well are greatly reduced.
3. The invention utilizes the water level difference to carry out siphon precipitation, the water flow is stable, and the soil loss in the precipitation process can be reduced.
4. Besides the filter screen wrapped outside the well pipe, the invention arranges a filter at the bottom end of the siphon branch pipe, and the filter is placed in water and is not easy to be blocked; the filter screen can be 300 meshes or more, and the filter effect is good; the filter screen can be cleaned and replaced, and the filtering effect is reliable.
5. The invention adopts two measures of water injection, air exhaust and air collection of the air collection tank, maintains the normal long-time running of the siphon, reduces the risk of siphon break, reduces the frequency of siphon restart, and is convenient for maintenance in the dewatering process.
Drawings
FIG. 1 is a schematic plan view of a siphon dewatering device connected in parallel with a foundation pit;
FIG. 2 is a schematic diagram of siphon start of a foundation pit parallel siphon precipitation apparatus;
FIG. 3 is a schematic view of a vapor collection canister;
FIG. 4 is a schematic diagram of the precipitation process of the foundation pit parallel siphon precipitation device;
FIG. 5 is a schematic plan view of a siphon dewatering device with two groups of dewatering wells staggered in foundation pit parallel;
FIG. 6 is a schematic diagram of a semi-closed check valve;
FIG. 7 is a schematic plan view of the first and second positioning members of the semi-closed check valve;
fig. 8 is a schematic diagram showing the state of opening (a) and closing (b) of the semi-closed check valve.
Reference numerals in the drawings are as follows: the water collection well 1, the dewatering well 2, the siphon 3, the siphon main pipe 31, the siphon branch pipe 32, the check valve 33, the filter 34, the drainage device 4, the water pump 41, the sump 42, the drainage ditch 43, the exhaust device 5, the water injection valve 51, the pressurized water source 52, the gas collection tank 6, the gas intake bottom valve 61, the gas discharge top valve 62, the water injection side valve 63, the water flow direction 7, the liquid level 8, the valve body 331, the valve plate 332, the first positioning member 333, the second positioning member 334, the guide rod 335, the first valve port 336, and the second valve port 337.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below. The technical features of the embodiments of the invention can be combined correspondingly on the premise of no mutual conflict.
In the description of the present invention, it will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected with intervening elements present. In contrast, when an element is referred to as being "directly connected" to another element, there are no intervening elements present.
In the description of the present invention, it should be understood that the terms "first" and "second" are used solely for the purpose of distinguishing between the descriptions and not necessarily for the purpose of indicating or implying a relative importance or implicitly indicating the number of features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature.
As shown in fig. 1, in a preferred embodiment of the present invention, a parallel siphon dewatering device for a foundation pit is provided, and its basic components include a water collecting well 1, a siphon pipe network 3, a drainage device 4, a water injection and exhaust device 5 and a gas collecting tank 6, where the parallel siphon dewatering device for a foundation pit is mainly used for synchronously dewatering a plurality of dewatering wells 2 in the foundation pit.
It should be noted that, the specific arrangement position and excavation form of the dewatering well 2 in the foundation pit need to be determined according to the design scheme and construction organization scheme of the foundation pit, and the specific arrangement position and excavation form can be adjusted according to the related existing specifications and actual engineering requirements, which are not described in detail. In this embodiment, the dewatering well 2 is excavated at the side of the foundation pit, and the depth of the dewatering well is required to be determined according to the requirement of dewatering of the foundation pit. The dewatering well 2 does not need to be provided with a water pump, and the diameter can be smaller than that of a conventional dewatering well as long as the water inlet requirement is met. The water collecting wells 1 can be excavated separately at the sides of the foundation pit, and the purpose of the water collecting wells is to make the height difference to collect the underground water in each dewatering well 2 by utilizing the siphon principle. The water collecting well 1 is deeper and larger in diameter than the dewatering well 2, so that the water level difference of siphon operation and the convenience of temporary water storage are ensured. Of course, if the corresponding water collection well 1 is present in the actual foundation pit engineering itself, separate excavation may not be required. As shown in fig. 2, siphon network 3 includes a main siphon pipe 31 and a plurality of branch siphon pipes 32. Siphon main pipe 31 serves as a main pipe section of whole siphon network 3 for collecting siphon branch pipes 32. Siphon main pipe 31 may be disposed on the ground of the foundation pit side where each dewatering well 2 is located, and its disposition path should be as close to the disposition site of each dewatering well 2 as possible, so as to avoid the flow resistance caused by the excessively long pipe side. For ease of description, the two ends of siphon main pipe 31 are referred to as the first end and the second end of siphon main pipe 31, respectively. The first end of the siphon main pipe 31 is connected to the water injection and exhaust device 5, and the siphon main pipe 31 extends downward in the depth direction of the water collection well 1 by one bend after passing through the wall of the water collection well 1 from the side, so that the second end extends below the liquid surface of the water collection well 1. To ensure reliability, the second end of siphon main 31 should be located at an elevation as low as possible below the elevation of the bottom of dewatering well 2. Each siphon branch pipe 32 corresponds to one dewatering well 2, i.e. each dewatering well 2 is connected to the siphon main pipe 31 by one siphon branch pipe 32. Also, for convenience of description, the two ends of the siphon branch pipe 32 are referred to as a first end and a second end of the siphon branch pipe 32, respectively. The first end of the siphon branch pipe 32 is connected with the siphon main pipe 31, the second end stretches into the dewatering well 2 and is sequentially connected with the check valve 33 and the filter 34, the top end of the check valve 33 is connected with the second end of the siphon branch pipe 32, and the bottom end of the check valve 33 is connected with the filter 34. The filter 34 is used to perform secondary decontaminating filtration of the well groundwater entering the siphon leg 32. And the check valve 33 is a check valve for controlling the water in the siphon branch pipe 32 to flow unidirectionally into the siphon main pipe 31 but not reversely into the dewatering well 2. The purpose of the check valve 33 in the present invention is to enable the siphon branch 32 to be filled with water during the siphon start phase.
The specific structure of the filter 34 in the present invention is not limited, and is based on the capability of trapping sediment in water. Considering reliability and cost problems in engineering application, as an implementation form of the embodiment of the present invention, the filter 34 may be composed of a framework and a filter screen, wherein the framework may be bent by a steel wire mesh to form a cylinder shape with an open top and a sealed bottom, and the filter screen is sleeved on the outer side wall and the bottom of the framework in a surrounding manner, so as to form a filtering structure for filtering sediment. If the bottom valve port of the check valve 33 is not connected to the external pipe, the entire filter 34 cylinder is wrapped at the bottom valve port of the check valve 33, and if the bottom valve port of the check valve 33 is connected to the external pipe, the entire filter 34 cylinder is wrapped at the opening of the external pipe of the check valve 33. In order to ensure the reliability of sediment filtration, a 300 mesh or more filter screen is used as the filter screen. Therefore, besides the filter screen wrapped outside the ordinary dewatering well pipe, the invention realizes double filtration by arranging the filter with a denser filter screen at the bottom end of the siphon branch pipe, thereby better avoiding the loss of water and soil, and facilitating the cleaning and replacement when the filter is blocked.
In addition, in the siphon operation process, the water in the siphon pipe network 3 is in a negative pressure state, so that the higher the lift, the larger the negative pressure. The water contains a large amount of air, and under the negative pressure state, the air can be separated out from the water to form bubbles. The accumulation of these bubbles can destroy the siphon effect, and thus require venting measures.
In the embodiment of the invention, the air is exhausted by arranging the air collecting tank 6 on the siphon main pipe 31. As shown in fig. 4, the bottom, top, and side portions of the gas collection tank 6 are provided with openings, respectively, referred to as a bottom opening, a top opening, and a side opening, respectively, for convenience of description. The bottom opening, the top opening and the side opening are respectively provided with an air inlet bottom valve 61, an air outlet top valve 62 and a water injection side valve 63 for controlling the opening to be opened and closed. The vapor collection tank 6 is installed at a front end position before the siphon main pipe 31 passes through the wall of the water collection well 1, and the highest water injection liquid level allowed by the water collection well 1 is higher than the top of the vapor collection tank 6. In order to ensure the gas collecting effect, the siphon main pipe 31 between the water injection and gas exhaust device 5 and the gas collecting tank 6 adopts an inclined arrangement with gradually increased elevation, and the gas collecting tank 6 is communicated with the highest elevation position of the siphon main pipe 31 through the bottom opening where the gas inlet bottom valve 61 is positioned. That is, the siphon main pipe 31 has a certain arrangement gradient, the elevation of the end part of the siphon main pipe 31 connected with the water injection and exhaust device 5 is the lowest, and the elevation of the position of the siphon main pipe 31 connected with the gas collection tank 6 is the highest, so that when bubbles exist in the siphon main pipe 31, the gas in each siphon branch pipe 32 automatically moves to the position of the gas collection tank 6, after entering the siphon main pipe 31, the gas in each siphon branch pipe 32 is gathered to the highest position of the siphon main pipe 31 along the water flow, and is gathered to the gas collection tank 6 in the state that the gas inlet bottom valve 61 is opened, so that the damage to the siphon is avoided.
The intake bottom valve 61, the exhaust top valve 62 and the water injection side valve 63 in the gas collection tank 6 may be respectively opened and closed in different stages. In the normal gas collection process, the gas collection tank 6 is initially filled with water, the gas inlet bottom valve 61 is opened, the other two valves are closed, and bubbles gradually enter the gas collection tank 6 to replace the water therein, so that the top of the siphon main pipe 31 is maintained in a bubble-free state. When the bubbles in the gas collection tank 6 are close to be full, the gas inlet bottom valve 61 is required to be closed, the gas exhaust top valve 62 is opened, then the water injection side valve 63 is connected with an external water injection pipe, the water injection side valve 63 is opened, water is injected into the gas collection tank 6 for gas exhaust, and therefore the gas collection tank 6 is filled with water again, and then normal gas collection is continued. Of course, the gas collection tank 6 may be manually or automatically controlled. The automatic control can be equal-interval automatic control with reasonable time intervals set according to actual gas collection conditions, or intelligent automatic control according to water level conditions by detecting the water level in the gas collection tank by adopting a sensor.
Further, water injection/evacuation device 5 at the end of main siphon pipe 31 serves to perform pressure water injection into main siphon pipe 31, and assist in evacuating air bubbles in main siphon pipe 31 by high-speed water flow, or assist in introducing air bubbles in main siphon pipe 31 into gas collection tank 6. Because of viscous resistance to bubbles in the inner wall of main siphon tube 31, the flow rate of water generated by the siphon may not be sufficient to allow all bubbles to be discharged from the second end of main siphon tube 31 or smoothly flow into vapor collection tank 6 by the water flow in the case where the difference in height is small. Therefore, if necessary, the pressure water can be injected into siphon main pipe 31, and the external water source having a high head pressure can be used to increase the flow rate in the pipe, thereby taking away the bubbles attached to the pipe wall. The majority of the entrained bubbles will be carried directly into the water collection well 1 and possibly a small part will be carried into the gas collection tank 6.
As an implementation form of the embodiment of the present invention, the water injection and exhaust device 5 includes a pressurized water source 52 and a water injection valve 51, an outlet of the pressurized water source 52 is connected to the first end of the siphon main pipe 31, and the water injection valve 51 is used for controlling the water path between the pressurized water source 52 and the siphon main pipe 31 to be opened and closed. When a water injection and venting operation is desired, water injection valve 51 between pressurized water source 52 and main siphon tube 31 may be opened to introduce high pressure water into main siphon tube 31.
The pressure water source 52 of the air discharging device may be tap water with water pressure, or may be other water sources on site, and if the pressure required for discharging the air bubbles in the pipe is insufficient, the air may be pressurized by a device such as a water pump and then introduced into the siphon main pipe 31.
In addition, the water accumulated in the water collection well 1 needs to be discharged through the drainage device 4, and the liquid level in the water collection well 1 needs to be regulated and controlled according to the actual precipitation requirement. In siphon precipitation, the liquid level in the water collection well 1 must be lower than the liquid level in the precipitation well 2, and the greater the difference in height between the two, the greater the siphon precipitation rate. Thus, the drainage means 4 may be provided as a device capable of controlling the amount of drainage in order to vary the level of liquid in the water collection well 1 by the difference in-and-out water flow.
As an implementation form of the embodiment of the present invention, the above-described drainage device 4 includes a water pump 41, a sump 42, and a drain 43. Wherein the water pump 41 is provided with a flexible output pipe in addition to the submersible pump body. The pump body of the water pump 41 is positioned below the liquid level of the water collecting well 1, and an output pipe at the outlet of the water pump 41 extends into a water collecting pit 42 connected with a drainage ditch 43 and is used for pumping water collected in the water collecting well 1 into the water collecting pit 42 and discharging the water through the drainage ditch 43. The purpose of the sump 42 is to prevent clogging of the drain 43 and adverse effects on the external environment, in order to perform sediment precipitation in advance before draining. To reduce the impact, the bottom of the pit 42 may be pebbled or cured with concrete.
The siphon network 3 is free from water in the initial state, and thus needs to be started by water injection in advance, so that a siphon effect of automatic drainage can be formed. The water in the siphon network 3 is injected into the water collection well 1 to fill the siphon main pipe 31 and each siphon branch pipe 32 in the reverse direction. Generally, if the pipe diameters of the main siphon pipe 31 and the branch siphon pipes 32 are large, a full pipe flow is not formed in the pipe during water injection, the original air in the pipe can be normally discharged through the space above the pipe, and the water gradually replaces the air in the pipe. However, in practical use, the pipe diameter of the siphon pipe network 3 is adjusted according to the precipitation requirement, and in order to ensure the formation of the siphon effect, a pipe with a smaller pipe diameter may be adopted. In particular, for the siphon branch 32, only a thin pipe of about 2cm is often used in most practical engineering. For such fine pipes, when the water in the water collection well 1 is pressed into the pipe network, a full pipe flow tends to be formed. If the lower part of the siphon branch pipe 32 still has air, and the top of the siphon branch pipe 32 is filled with water, the air in the pipe cannot be automatically discharged due to the unidirectional conduction limitation of the bottom check valve 33, which easily causes that the siphon branch pipe 32 is difficult to be filled with water, and thus the siphon process cannot be started normally.
To solve such a problem, as one implementation form of the embodiment of the present invention, the check valve 33 is designed as a semi-closed check valve. As shown in fig. 6, the semi-closed check valve includes a valve body 331, a valve plate 332, a first positioning member 333, a second positioning member 334, and a guide rod 335. The valve 331 is internally provided with a hollow flow passage, and both ends of the valve 331 are respectively provided with a first valve port 336 and a second valve port 337 which are communicated with the flow passage in the valve. The valve plate 332, the first positioning member 333, the second positioning member 334 and the guide rod 335 are disposed inside the valve body 331. The flow passage in the valve body 331 is provided with a valve seat, the position of the valve seat is a step surface, and the section of the upper flow passage is larger than that of the lower flow passage. The valve plate 332 plays a role of a valve core in the valve, and can be matched with a valve seat under the matching of the guide rod 335, the first positioning piece 333 and the second positioning piece 334 to play a role of controlling the opening and closing of the valve. Specifically, the first positioning member 333 and the second positioning member 334 are disposed in parallel on two cross sections in the valve body cavity and are located on both sides of the valve seat, respectively, the first positioning member 333 is above the valve seat, and the second positioning member 334 is below the valve seat. The guide rod 335 vertically passes through the center of the valve sheet 332 and is coupled to the valve sheet 332, and the guide rod 335 is disposed along the inner flow path axis of the valve body 331, so that the valve sheet 332 is perpendicular to the inner flow path axis of the valve body 331. The two ends of the guide rod 335 form sliding pairs with the first locating piece 333 and the second locating piece 334 respectively, so as to ensure that the guide rod 335 moves along the axial direction. As shown in fig. 7, the first positioning member 333 and the second positioning member 334 are water permeable discs with a guide hole in the center, the outermost part of the discs is a peripheral ring matching with the cross section, an inner ring is arranged in the center of the peripheral disc, the center of the inner ring is used as the guide hole, and the inner ring is supported on the peripheral ring of the disc through three support rods which form an angle of 120 degrees with each other. The outer diameter of the guide rod 335 is slightly smaller than the aperture of the upper and lower guide holes, and two ends of the guide rod 335 respectively penetrate into the two guide holes of the first positioning piece 333 and the second positioning piece 334 to form a guide mechanism. The valve plate 332 and the valve seat form an opening and closing mechanism guided by a guide rod 335, and the working principle is as follows: when fluid flows from the first valve port 336 to the second valve port 337, the valve plate 332 is pushed to be separated from the valve seat, and a valve flow passage is opened; when fluid flows from the second valve port 337 to the first valve port 336, the valve plate 332 is pushed to press against the valve seat, and the flow path in the valve is closed. The semi-closed check valve is the most different from the common check valve in that the valve plate 332 is provided with a plurality of breathable micro-permeable capillary holes, the reverse flow of water can be effectively prevented through the semi-closed check valve, but air with certain pressure is allowed to freely circulate, and the efficiency of water injection and air exhaust when full pipe flow occurs in a pipe is improved. In practical application, the diameter of the capillary holes is generally less than 1mm, so as to realize the effect of ventilation and micro water permeation. The breathable micro-permeable water refers to that gas is allowed to pass through capillary holes, but water is not allowed to pass through preferably, that is, the valve plate is in an optimal state to only allow gas to pass through and not allow water to pass through, but in practical application, water is not required to be absolutely forbidden to flow through, and if some water passes through, the realization of the functional effect of the invention is not affected remarkably.
When the semi-closed check valve is adopted, even if the top of the siphon branch pipe 32 is full pipe flow in the siphon starting process, air at the lower part of the siphon branch pipe 32 is compressed to a certain pressure and then discharged through capillary holes on the valve plate 332, so that the siphon branch pipe 32 is filled with water, and the water injection efficiency and the normal realization of the siphon function are ensured.
In addition, it should be noted that the dewatering wells 2 at the bottom of the foundation pit in the present invention may be arranged in only one group, or may be grouped, for example, into 2 groups or more groups. As shown in fig. 5, taking two sets of dewatering wells 2 as an example, each set of dewatering wells 2 is provided with a separate set of siphon pipe network 3, water injection and exhaust device 5 and gas collection tank 6. If the siphon pipes of one group of dewatering wells 2 fail, the siphon pipes of other groups of dewatering wells 2 can still normally operate, so that the whole foundation pit dewatering effect is prevented from failing immediately, and the maintenance time is strived for.
Therefore, the foundation pit parallel siphon dewatering device can be used for dewatering at the side of the foundation pit, because each dewatering well is communicated through the siphon, the water level elevation of each dewatering well is similar, the effect of simultaneously controlling a plurality of dewatering wells can be achieved by only controlling the water pump in the water collecting well and monitoring the water level of one dewatering well, and the complexity of dewatering control is reduced.
In order to better understand the concrete dewatering control process of the invention, the foundation pit parallel siphon dewatering construction method is further provided based on the foundation pit parallel siphon dewatering device.
In a preferred embodiment of the present invention, a construction method for siphon precipitation in parallel of a foundation pit based on the siphon precipitation apparatus in parallel of a foundation pit includes the following steps:
s1, excavating a dewatering well 2 in a foundation pit to be subjected to dewatering, excavating a water collecting well 1, a water collecting pit 42 and a drainage ditch 43 outside the foundation pit, and then installing a siphon pipe network 3, a drainage device 4, a water injection exhaust device 5 and a gas collection tank 6 to form the foundation pit parallel siphon dewatering device.
It should be noted that the construction of dewatering well, water collecting pit and drainage ditch can refer to the prior art, and the concrete excavation size and mode can be adjusted according to the actual engineering condition. The specific installation of the siphon network 3, the drainage device 4, the water injection and exhaust device 5 and the gas collection tank 6 is described with reference to fig. 1 to 4, and a specific connection form will not be described again. During construction, the siphon main pipe 31 can be horizontally arranged near the mouth of each precipitation well 2, one end of the siphon main pipe is connected with the exhaust device 5, the other end of the siphon main pipe penetrates through the wall of the water collecting well 1, and the siphon main pipe is bent ninety degrees to extend downwards into the water collecting well 1, and the pipe orifice is located at a certain depth below the water surface, so that the pipe orifice can be located in water in the whole precipitation process. The siphon main pipe 31 is horizontally provided with a bracket or a lower soil block to keep a small gradient, so that the elevation of the position where the gas collection tank 6 is arranged is highest, and the gas collection tank 6 is facilitated to be filled with bubbles. The gap of the siphon main pipe 31 penetrating through the wall of the water collecting well 1 is blocked by glass cement, and the water leakage prevention measure is made. The exhaust device 5 is normally closed and is opened when exhaust is required. And a siphon branch pipe 32 is respectively arranged in each precipitation well 2, the top end of the siphon branch pipe 32 is connected to the siphon main pipe 31, the siphon branch pipe 32 is connected with a check valve 33 and a filter 24 at the bottom end in advance before sinking into the precipitation well 2, and the bottom pipe orifice is required to be positioned below the lowest precipitation height during pipe sinking, so that the pipe orifice can be positioned in water in the whole precipitation process. A submersible pump in the drainage device 4 is installed in the water collection well 1, and an output pipe for drainage is connected to the water collection pit 42, and a water level control device can be installed in the water collection well 1, so that automatic control can be realized.
S2, opening an air inlet bottom valve 61 and an air outlet top valve 62 of the air collection tank 6, and closing a water injection side valve 63 of the air collection tank 6; the water is injected into the water collecting well 1 through an external water source, the water level in the water collecting well 1 is kept higher than the highest point of the siphon main pipe 31, so that the water in the water collecting well 1 flows into the siphon main pipe 31 and further flows into each siphon branch pipe 32, and the valve plate 332 in the check valve 33 at the tail end of the siphon branch pipe 32 is pressed on the valve seat under the pressure in the pipe, so that the flow passage in the valve is closed. During the water injection process, the water in the siphon branch pipe 32 cannot directly flow into the dewatering well 2, and a part of the original air in the siphon pipe network 3 is expelled from the check valve 33 at the bottom end of the siphon branch pipe 32 by water flow, and the other part of the air is upwards reversely collected in the gas collection tank 6 through the siphon pipe network 3 and is expelled from the gas outlet top valve 62 of the gas collection tank 6. When the siphon pipe network 3 is filled with water, the water overflows from the exhaust top valve 62 of the gas collecting tank 6, at this time, the exhaust top valve 62 of the gas collecting tank 6 is closed, and the water injection of the siphon pipe network 3 is completed, so that siphons are formed.
S3, after the siphon network 3 is filled with water, the water pump 41 in the water collecting well 1 is started, the water in the water collecting well 1 is continuously discharged into the water collecting pit 42, and when the water level of the water collecting well 1 is reduced to be lower than the water level of any dewatering well 2, the water in the corresponding dewatering well 2 starts to automatically flow into the water collecting well 1 through the siphon principle. The water discharged into the sump 42 is discharged through the drain 43 after being precipitated.
During siphon precipitation, water level control and siphon operation control need to be performed.
The water level is controlled as follows:
in the siphon dewatering process, the water level difference between the liquid level in the water collecting well 1 and the liquid level of each dewatering well 2 is regulated by controlling the flow of the water pump 41, so that the dewatering depth in each dewatering well 2 is controlled to meet the design requirement. Specifically, after precipitation begins, along with the water level of the water collecting well, a water level difference is generated between the water collecting well and each precipitation well, water in each precipitation well flows into the water collecting well by a siphon principle, and the precipitation process is related to the flow of the water pump. When the flow of the water pump is smaller, the water level in the water collecting well drops slowly, the water level difference between the dewatering well and the water collecting well is small, the siphon flow rate is slower, the water level in each dewatering well drops slowly, the water level is stabilized there after a certain dropping depth, the designed dewatering depth can not be reached, and the water pump with large flow is needed to be used at the moment. When the flow rate of the water pump is large, the water level in the water collecting well drops faster, the siphon flow speed is accelerated along with the increase of the water level difference of the precipitation well and the water collecting well, water in each precipitation well quickly flows into the water collecting well, after the water level of the precipitation well reaches the designed descending depth, the water pump is stopped for drainage, and after the water level of each precipitation well is restored to the set water level, the water pump is started for drainage again, so that circulation is performed. The water level depth can be monitored through an automatic water level control system, and the automatic starting and stopping of the water pump can be controlled. The water pump with proper flow is selected, so that the starting and stopping period of the water pump can be reduced, and the service life of the water pump can be prolonged.
The siphon operation is controlled as follows:
in the siphon operation process, the water in the siphon is in a negative pressure state, and the higher the lift is, the larger the negative pressure is. The water contains a large amount of air, and under the negative pressure state, the air can be separated out from the water to form bubbles. When the flow rate is high, bubbles are taken away along with the water flow, but when the water flow is low, bubbles are accumulated at the top of the siphon pipe, more bubbles are accumulated, the flow rate is affected, and if more bubbles are accumulated, flow interruption is caused. After the current is cut off, the siphon needs to be restarted to continue precipitation. Therefore, to ensure proper operation of the siphon, two measures are taken: 1. the gas collection function is regulated by switching a valve of a gas collection tank through the gas collection tank arranged at the highest point of the siphon main pipe; 2. and injecting high-flow pressurized water into the siphon main pipe at regular time through the exhaust device to form water flow with a certain flow speed, and taking away bubbles accumulated in the siphon main pipe. Therefore, the specific control mode of the two measures in actual construction is as follows:
during siphon precipitation, the air inlet bottom valve 61 on the air collection tank 6 is initially kept in an open state, and the water injection side valve 63 and the air exhaust top valve 62 are in a closed state, so that air bubbles in the pipe are continuously collected into the air collection tank 6 along with water flow. When the space occupied by the air in the air collection tank 6 reaches a set value, the air inlet bottom valve 61 of the air collection tank 6 is closed, and the air collection tank 6 and the siphon pipe network 3 are disconnected, wherein the set value can be generally set to be basically full of the air; then the exhaust top valve 62 of the gas collection tank 6 is opened, and then water is injected into the gas collection tank 6 through the water injection side valve 63 to replace the internal air; after the water is filled in the air collection tank 6, the water filling side valve 63 and the exhaust top valve 62 are closed, the air inlet bottom valve 61 is opened again, the air collection tank 6 and the siphon pipe network 3 are communicated, and the air collection function of the air collection tank 6 is recovered.
In the siphon dewatering process, the water injection and exhaust device 5 operates regularly, the flow speed of water in the siphon main pipe 31 is increased by pressure water, and bubbles which are accumulated at the top of the inner pipe wall of the siphon main pipe 31 and influence normal operation of the siphon are taken away. The specific operation time of the water injection and exhaust device 5 can be determined according to the accumulation condition of bubbles in the pipe, and the operation interval can be optimized according to the actual condition.
S4, after precipitation is finished, recycling the siphon pipe network 3, the drainage device 4, the water injection and exhaust device 5 and the gas collection tank 6, backfilling the precipitation well 2 and the water collection well 1, and completing the whole precipitation construction process.
In addition, it should be noted that, in the siphon precipitation process, if the filter 34 is blocked, the filter 34 is taken out for cleaning or replacement of the filter screen, then the filter 34 is replaced to the original position, and the siphon is restarted in S2, so as to continue the siphon precipitation.
The above embodiment is only a preferred embodiment of the present invention, but it is not intended to limit the present invention. Various changes and modifications may be made by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present invention. Therefore, all the technical schemes obtained by adopting the equivalent substitution or equivalent transformation are within the protection scope of the invention.
Claims (10)
1. The siphon dewatering device is characterized by comprising a water collecting well (1), a siphon pipe network (3), a drainage device (4), a water injection and exhaust device (5) and a gas collecting tank (6), and is used for synchronously dewatering a plurality of dewatering wells (2) in the foundation pit;
the siphon pipe network (3) comprises a main siphon pipe (31) and a plurality of branch siphon pipes (32); the siphon main pipe (31) is arranged on the ground of the foundation pit side where each dewatering well (2) is located, the first end part of the siphon main pipe (31) is connected with the water injection and exhaust device (5), and the second end part of the siphon main pipe (31) penetrates through the wall of the water collecting well (1) and then is positioned below the liquid level of the water collecting well (1); each siphon branch pipe (32) corresponds to one dewatering well (2), the first end part of each siphon branch pipe (32) is connected with a siphon main pipe (31), and the second end part extends into the dewatering well (2) and is sequentially connected with a check valve (33) and a filter (34); the filter (34) is used for carrying out secondary impurity removal and filtration on underground water in a well entering the siphon branch pipe (32), and the check valve (33) is a one-way valve and is used for controlling water in the siphon branch pipe (32) to flow unidirectionally into the siphon main pipe (31) but not flow reversely into the dewatering well (2);
the bottom, the top and the side parts of the gas collection tank (6) are respectively provided with an opening, and are respectively provided with a gas inlet bottom valve (61), a gas outlet top valve (62) and a water injection side valve (63) for controlling the opening to be opened and closed; the gas collection tank (6) is arranged at the position where the siphon main pipe (31) passes through the front end of the well wall of the water collection well (1), and the highest water injection liquid level allowed by the water collection well (1) is higher than the top of the gas collection tank (6); the siphon main pipe (31) between the water injection and exhaust device (5) and the gas collection tank (6) is arranged in an inclined way with gradually increased elevation, and the gas collection tank (6) is communicated with the highest elevation position of the siphon main pipe (31) through the bottom opening of the air inlet bottom valve (61), so that gas in the rest pipe sections can be collected into the gas collection tank (6);
The water injection and exhaust device (5) is used for injecting water into the siphon main pipe (31) under pressure, and assisting bubbles in the siphon main pipe (31) to be discharged from the second end part or enter the gas collection tank (6) along with high-speed water flow;
the drainage device (4) is used for draining water accumulated in the water collecting well (1).
2. The foundation pit parallel siphon precipitation device according to claim 1, wherein the water injection and exhaust device (5) comprises a pressure water source (52) and a water injection valve (51), an outlet of the pressure water source (52) is connected with the first end part of the siphon main pipe (31), and the water injection valve (51) is used for controlling water path on-off between the pressure water source (52) and the siphon main pipe (31).
3. The siphon dewatering device in parallel for foundation pit according to claim 1, wherein the check valve (33) is a semi-closed check valve, comprising a valve body (331), a valve plate (332), a first positioning member (333), a second positioning member (334) and a guide rod (335); the two ends of the valve body (331) are respectively provided with a first valve port (336) and a second valve port (337) which are communicated with the flow passage in the valve, and the valve plate (332), the first positioning piece (333), the second positioning piece (334) and the guide rod (335) are all arranged in the valve body (331); the first positioning piece (333) and the second positioning piece (334) are arranged on two cross sections in the inner cavity of the valve body in parallel and are respectively positioned on two sides of the valve seat; the guide rod (335) vertically passes through the center of the valve plate (332) and is fixedly connected with the valve plate (332), and two ends of the guide rod (335) respectively form a sliding pair for ensuring the guide rod (335) to move along the axial direction with the first positioning piece (333) and the second positioning piece (334); the valve plate (332) and the valve seat form an opening and closing mechanism guided by a guide rod (335); when fluid flows from the first valve port (336) to the second valve port (337), the valve plate (332) is separated from the valve seat, and a valve flow path is opened; when fluid flows from the second valve port (337) to the first valve port (336), the valve plate (332) is pressed on the valve seat, and the flow passage in the valve is closed; capillary holes with diameters not exceeding 1mm are formed in the valve plate (332).
4. A siphon dewatering device in parallel for foundation pit according to claim 3, wherein the first positioning member (333) and the second positioning member (334) are water-permeable discs with a guiding hole in the center, and two ends of the guiding rod (335) respectively penetrate into the two guiding holes to form a guiding mechanism.
5. The device for siphon precipitation in parallel of foundation pit according to claim 1, wherein the filter (34) comprises a framework and a filter screen, the filter screen is sleeved outside the framework in a surrounding manner, and a filtering structure wrapping the valve port of the check valve (33) is formed.
6. The pit parallel siphon precipitation device according to claim 1, wherein the drainage device (4) comprises a water pump (41), a sump (42) and a drain (43); the water pump (41) is positioned below the liquid level of the water collecting well (1), and an output pipe at the outlet of the water pump (41) extends into a water collecting pit (42) connected with a drainage ditch (43) and is used for pumping water collected in the water collecting well (1) into the water collecting pit (42) and discharging the water outside through the drainage ditch (43).
7. The foundation pit parallel siphon precipitation device according to claim 1, wherein all precipitation wells (2) in the foundation pit are divided into a plurality of groups, and each group of precipitation wells (2) is provided with a separate set of siphon pipe network (3), water injection and exhaust device (5) and gas collection tank (6).
8. The pit parallel siphon precipitation apparatus according to claim 5, wherein the filter screen is 300 mesh or more.
9. A construction method of parallel siphon precipitation of foundation pit based on the parallel siphon precipitation device of claim 3, comprising the following steps:
s1, excavating a dewatering well (2) in a foundation pit to be subjected to dewatering, excavating a water collecting well (1), a water collecting pit (42) and a drainage ditch (43) outside the foundation pit, and then installing a siphon pipe network (3), a drainage device (4), a water injection and exhaust device (5) and a gas collection tank (6) to form the foundation pit parallel siphon dewatering device;
s2, opening an air inlet bottom valve (61) and an air outlet top valve (62) of the air collection tank (6), and closing a water injection side valve (63) of the air collection tank (6); injecting water into the water collecting well (1) through an external water source and keeping the water level in the water collecting well (1) higher than the highest point of the siphon main pipe (31), so that the water in the water collecting well (1) flows into the siphon main pipe (31) and further flows into each siphon branch pipe (32), and a valve plate (332) in a check valve (33) at the tail end of each siphon branch pipe (32) is pressed on the valve seat under the pressure in the pipe, so that a valve inner flow passage is closed; in the water injection process, water in the siphon branch pipe (32) cannot directly flow into the dewatering well (2), part of the original air in the siphon pipe network (3) is expelled from the check valve (33) at the bottom end of the siphon branch pipe (32) by water flow, and the other part of the original air is upwards reversely collected in the gas collection tank (6) through the siphon pipe network (3) and is expelled from the gas outlet top valve (62) of the gas collection tank (6); when the siphon pipe network (3) is filled with water, the water overflows from the exhaust top valve (62) of the gas collection tank (6), at the moment, the exhaust top valve (62) of the gas collection tank (6) is closed, and the water injection of the siphon pipe network (3) is completed to form siphons;
S3, after the siphon network (3) is filled with water, a water pump (41) in the water collecting well (1) is started to continuously discharge water in the water collecting well (1) into the water collecting pit (42), when the water level of the water collecting well (1) is lower than the water level of any dewatering well (2), water in the corresponding dewatering well (2) starts to automatically flow into the water collecting well (1) through a siphon principle, and the water discharged into the water collecting pit (42) is discharged through a drainage ditch (43) after precipitation;
in the siphon precipitation process, the water level difference between the liquid level in the water collecting well (1) and the liquid level of each precipitation well (2) is regulated by controlling the flow of the water pump (41), so that the precipitation depth in each precipitation well (2) is controlled to meet the design requirement;
in the siphon dewatering process, an air inlet bottom valve (61) on the air collection tank (6) is initially kept in an open state, and a water injection side valve (63) and an air exhaust top valve (62) are in a closed state, so that bubbles in the pipe are continuously collected into the air collection tank (6) along with water flow; when the space occupied by the air in the air collection tank (6) reaches a set value, closing an air inlet bottom valve (61) of the air collection tank (6), disconnecting the air collection tank (6) and the siphon pipe network (3), then opening an air outlet top valve (62) of the air collection tank (6), and filling water into the air collection tank (6) through a water filling side valve (63) to replace the internal air; after the water is filled in the air collection tank (6), the water filling side valve (63) and the exhaust top valve (62) are closed, the air inlet bottom valve (61) is opened again, the air collection tank (6) and the siphon pipe network (3) are communicated, and the air collection function of the air collection tank (6) is recovered;
In the siphon dewatering process, the water injection and exhaust device (5) operates regularly, the flow speed of water in the siphon main pipe (31) is increased by pressure water, and bubbles which are accumulated at the top of the inner pipe wall of the siphon main pipe (31) and influence normal operation of the siphon are taken away;
s4, after precipitation is finished, recycling the siphon pipe network (3), the drainage device (4), the water injection and exhaust device (5) and the gas collection tank (6), and backfilling the precipitation well (2) and the gas collection well (1).
10. The method for constructing the parallel siphon precipitation of the foundation pit according to claim 9, wherein in the siphon precipitation process, if the filter (34) is blocked, the filter (34) is taken out for cleaning or replacing the filter screen, then the filter (34) is replaced to the original position again, the siphon is restarted in S2, and the siphon precipitation is continued.
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| CN202210962959.8A CN115162388B (en) | 2022-08-11 | 2022-08-11 | Foundation pit parallel siphon dewatering device and dewatering construction method |
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| CN202210962959.8A CN115162388B (en) | 2022-08-11 | 2022-08-11 | Foundation pit parallel siphon dewatering device and dewatering construction method |
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| CN202210962959.8A Active CN115162388B (en) | 2022-08-11 | 2022-08-11 | Foundation pit parallel siphon dewatering device and dewatering construction method |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011236876A (en) * | 2010-05-13 | 2011-11-24 | Tatsumi Morimoto | Drainage device |
| CN105256818A (en) * | 2015-11-18 | 2016-01-20 | 徐中山 | One pump-multi well deep foundation pit tube well synchronous pumping and drainage drawdown device |
| CN110616795A (en) * | 2019-10-24 | 2019-12-27 | 北京市市政工程设计研究总院有限公司 | Backflow pool device applying siphon drainage and operation method thereof |
| CN111237261A (en) * | 2020-03-17 | 2020-06-05 | 中国地质科学院水文地质环境地质研究所 | Siphon drainage structure and using method thereof |
| CN211852309U (en) * | 2020-03-17 | 2020-11-03 | 中国地质科学院水文地质环境地质研究所 | Siphon drainage structure |
| CN114808864A (en) * | 2021-01-18 | 2022-07-29 | 淮安市水利勘测设计研究院有限公司 | Method for solving rear drainage failure of water gate wing wall |
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011236876A (en) * | 2010-05-13 | 2011-11-24 | Tatsumi Morimoto | Drainage device |
| CN105256818A (en) * | 2015-11-18 | 2016-01-20 | 徐中山 | One pump-multi well deep foundation pit tube well synchronous pumping and drainage drawdown device |
| CN110616795A (en) * | 2019-10-24 | 2019-12-27 | 北京市市政工程设计研究总院有限公司 | Backflow pool device applying siphon drainage and operation method thereof |
| CN111237261A (en) * | 2020-03-17 | 2020-06-05 | 中国地质科学院水文地质环境地质研究所 | Siphon drainage structure and using method thereof |
| CN211852309U (en) * | 2020-03-17 | 2020-11-03 | 中国地质科学院水文地质环境地质研究所 | Siphon drainage structure |
| CN114808864A (en) * | 2021-01-18 | 2022-07-29 | 淮安市水利勘测设计研究院有限公司 | Method for solving rear drainage failure of water gate wing wall |
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