CN115162388A - 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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- CN115162388A CN115162388A CN202210962959.8A CN202210962959A CN115162388A CN 115162388 A CN115162388 A CN 115162388A CN 202210962959 A CN202210962959 A CN 202210962959A CN 115162388 A CN115162388 A CN 115162388A
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- 238000010276 construction Methods 0.000 title claims abstract description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 412
- 238000001556 precipitation Methods 0.000 claims abstract description 105
- 238000002347 injection Methods 0.000 claims abstract description 69
- 239000007924 injection Substances 0.000 claims abstract description 69
- 238000000034 method Methods 0.000 claims abstract description 35
- 230000008569 process Effects 0.000 claims abstract description 32
- 239000007788 liquid Substances 0.000 claims description 16
- 238000007599 discharging Methods 0.000 claims description 14
- 238000001914 filtration Methods 0.000 claims description 10
- 239000012530 fluid Substances 0.000 claims description 6
- 230000007246 mechanism Effects 0.000 claims description 6
- 238000013461 design Methods 0.000 claims description 4
- 230000000149 penetrating effect Effects 0.000 claims description 4
- 230000002441 reversible effect Effects 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims description 3
- 238000004062 sedimentation Methods 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 14
- 239000002689 soil Substances 0.000 abstract description 6
- 238000012544 monitoring process Methods 0.000 abstract description 4
- 230000001276 controlling effect Effects 0.000 description 13
- 230000006870 function Effects 0.000 description 8
- 238000009825 accumulation Methods 0.000 description 3
- 238000009412 basement excavation Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit 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
- 238000005553 drilling Methods 0.000 description 1
- 238000005429 filling process Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000011521 glass 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
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000008439 repair process Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000013049 sediment Substances 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
- 238000013022 venting Methods 0.000 description 1
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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 precipitation device and a precipitation construction method, and belongs to the field of foundation pit engineering construction. The basic assembly of the foundation pit parallel siphon precipitation 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 carrying out precipitation treatment on a plurality of precipitation wells in the foundation pit. The invention uses the water head to siphon and reduce water, the water flow is stable, the soil loss in the water reducing process can be reduced, the end part of the siphon branch pipe is provided with the filter, and the filter screen is denser, so that the filter effect is better, and the siphon branch pipe can be cleaned and replaced. The invention can simultaneously treat the drainage of a plurality of dewatering wells, 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 close due to the siphonage. Therefore, the invention can achieve the effect of controlling a plurality of precipitation wells simultaneously by only controlling one water pump and monitoring the water level of one precipitation well, thereby reducing the complexity of precipitation control, saving cost and easily controlling 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 urbanization, underground spaces are developed more and more, and foundation pit precipitation is often involved in the underground space development process. The foundation pit dewatering mode commonly used at present is tube well dewatering. The tube well precipitation is to lower the underground water by drilling a well inside and outside a foundation pit, placing a well pipe and a filter in the well, and then putting a water pump into the well pipe to pump water.
The tube well precipitation has the following problems in the using process: (1) The filter has poor reliability and is easy to damage, and the damaged filter is difficult to repair or replace; (2) Along with the change of the water level, the water pump needs to be frequently started and stopped in the precipitation process, when the water pump is started and stopped, a large vortex can be generated, and fine particles in soil are easily brought out along with water flow, so that the soil loss is caused; (3) A water pump is placed 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 over-reduction or under-reduction is easy to occur.
Disclosure of Invention
The invention aims to overcome the defects of complex control of foundation pit dewatering and low filtration reliability in the prior art, and provides a foundation pit parallel siphon dewatering device and a dewatering construction method.
The invention adopts the following specific technical scheme:
the invention provides a foundation pit parallel siphon precipitation 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 collecting well, the siphon pipe network, the drainage device, the water injection and exhaust device and the gas collecting tank are used for synchronously carrying out precipitation treatment on a plurality of precipitation wells in a foundation pit;
the siphon pipe network comprises a siphon main pipe and a plurality of siphon branch pipes; the siphon main pipe is arranged on the ground beside a foundation pit where each dewatering well is located, the first end of the siphon main pipe is connected with the water injection and exhaust device, and the second end 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, the first end of each siphon branch pipe is connected with the main siphon pipe, and the second end of each siphon branch pipe extends into the dewatering well and is sequentially connected with the check valve and the filter; the filter is used for carrying out secondary impurity removal and filtration on underground water in the well 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 in a one-way mode to enter the siphon main pipe but not flow into the dewatering well in a reverse mode;
the bottom, the top and the side part of the gas collecting tank are respectively provided with an opening, and an air inlet bottom valve, an exhaust top valve and a water injection side valve which are used for controlling the opening to be opened and closed are respectively arranged on the bottom, the top and the side part of the gas collecting tank; the gas collection tank is arranged at the position where the siphon main pipe penetrates through the front end of the well wall of the water collecting well, and the highest water injection level allowed by the water collecting 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 obliquely arranged in an increasing height manner, and the gas collection tank is communicated with the highest height position of the siphon main pipe through a bottom opening where the gas inlet bottom valve is located, so that gas in the rest pipe sections can be collected into the gas collection tank;
the water injection and exhaust device is used for injecting water into the siphon main pipe under pressure, and bubbles in the auxiliary siphon main pipe are discharged from the second end part or enter the gas collecting tank along with high-speed water flow;
the drainage device is used for discharging water accumulated in the water collecting well.
Above-mentioned technical scheme has solved siphon operation in-process, and the problem that the siphon velocity of flow or cutout are influenced to the easy accumulation of pipe top bubble has improved the convenience of precipitation in-process water level control, reduces the work load of water level control, reduces the emergence of the super-drop or the undercurrent condition simultaneously.
As a preferable preference of the first aspect, the water injection and exhaust device includes a pressure water source and a water injection valve, an outlet of the pressure water source is connected to the first end of the siphon main pipe, and the water injection valve is used for controlling the on-off of a water path between the pressure water source and the siphon main pipe.
As a preferred preference of the first aspect, the check valve is a semi-closed check valve, and comprises a valve body, a valve plate, a first positioning piece, a second positioning piece and a guide rod; the two ends of the valve body are respectively provided with a first valve port and a second valve port which are communicated with a flow passage in the valve, and the valve plate, the first positioning piece, the second positioning piece and the guide rod are 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 penetrates 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 with the first positioning piece and the second positioning piece for ensuring the guide rod to move along the axial direction; 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 flow passage in the valve 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 flow channel in the valve is closed; capillary holes with the diameter not more than 1mm are formed in the valve plate.
Preferably, the first positioning element and the second positioning element are both water-permeable discs with guide holes at the centers, and two ends of the guide rod respectively penetrate into the two guide holes to form the guide mechanism.
Preferably, the filter includes a framework and a filter screen, and the filter screen is sleeved around the framework to form a filter structure for wrapping the valve port of the check valve.
As a preferable aspect of the first aspect, the drainage means includes a water pump, a sump, and a drainage ditch; 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 water pump extends into the water collecting pit connected with the drainage ditch and is used for pumping the water collected in the water collecting well into the water collecting pit and discharging the water through the drainage ditch.
Preferably, all the dewatering wells in the foundation pit are divided into a plurality of groups, and each group of dewatering wells is provided with a set of siphon network, a water injection and air exhaust device and a gas collecting tank.
Preferably, the screen of the first aspect is a 300-mesh screen or a denser screen.
In a second aspect, the invention provides a foundation pit parallel siphon dewatering construction method based on the foundation pit parallel siphon dewatering device in the first aspect, which comprises the following steps:
s1, excavating a precipitation well in a foundation pit to be subjected to precipitation, excavating a water collecting well, a water collecting pit and a drainage ditch outside the foundation pit, and then installing a siphon pipe network, a drainage device, a water injection and exhaust device and a gas collection tank to form the foundation pit parallel siphon precipitation device;
s2, opening an air inlet bottom valve and an air exhaust top valve of the gas collecting tank, and closing a water injection side valve of the gas collecting 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 a valve plate in a check valve at the tail end of each siphon branch pipe is pressed on the valve seat under the pressure in the pipe, so that a flow passage in the valve is closed; in the water injection process, water in the siphon branch pipe cannot directly flow into the dewatering well, part of the original air in the siphon pipe network is driven by water flow to be discharged from the check valve at the bottom end of the siphon branch pipe, and the other part of the original air is reversely upwards collected in the gas collecting tank through the siphon pipe network and discharged from the exhaust top valve of the gas collecting tank; when the siphon pipe network is filled with water, the water can overflow from the exhaust top valve of the gas collecting tank, the exhaust top valve of the gas collecting tank is closed at the moment, and the siphon pipe network finishes water injection to form siphon;
s3, after the siphon pipe network 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, and when the water level of the water collecting well is lowered to be lower than the water level of any dewatering well, automatically flowing the water in the corresponding dewatering well into the water collecting well through a siphon principle, discharging the water into the water collecting pit, and discharging the water through a drainage ditch after sedimentation;
in the siphon precipitation process, the water level difference between the liquid level in the water collecting well and the liquid level of each precipitation well is adjusted by controlling the flow of the water pump, so that the precipitation depth in each precipitation well is controlled to meet the design requirement;
in the siphon precipitation process, initially keeping an air inlet bottom valve on the gas collecting tank in an open state, and keeping a water injection side valve and an exhaust top valve in a closed state, so that bubbles in a pipe are continuously collected into the gas collecting tank along with the flow of water flow; when the space occupied by the air in the air collecting tank reaches a set value, closing an air inlet bottom valve of the air collecting tank, disconnecting the air collecting tank and a siphon pipe network, then opening an exhaust top valve of the air collecting tank, and injecting water into the air collecting tank through a water injection side valve to replace the internal air; after the gas collecting tank is filled with water, closing the water injection side valve and the exhaust top valve, and then opening the air inlet bottom valve again to communicate the gas collecting tank and the siphon network, so as to recover the gas collecting function of the gas collecting tank;
in the siphon precipitation process, the water injection and exhaust device runs regularly, the flow velocity of water in the siphon main pipe is improved through pressure water, and bubbles which are gathered on the top of the inner pipe wall of the siphon main pipe and influence normal operation of siphon are taken away;
and S4, after precipitation is finished, recovering 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.
Preferably, in the second aspect, in the siphon precipitation process, if the filter is clogged, the filter is taken out and the filter is cleaned or replaced, and then the filter is replaced with the original position again, and S2 is executed again to restart the siphon to continue the siphon precipitation.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention can simultaneously treat the drainage of a plurality of dewatering wells, only needs to arrange a water pump 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 simultaneously controlling a plurality of dewatering wells by only controlling one water pump and monitoring the water level of one dewatering well. The complexity of precipitation control is reduced, the precipitation labor cost 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 in the dewatering well, and the diameter of the dewatering well can be very small under the condition that the dewatering well meets the water inlet requirement. The diameter of the dewatering well is larger due to the fact that a water pump needs to be placed in the common pipe well. The diameter of the dewatering well is greatly reduced, and the costs of pore forming, backfilling and the like of the dewatering well are greatly reduced.
3. The invention uses water head to siphon precipitation, the water flow is stable, and the soil loss in the precipitation process can be reduced.
4. Except for the filter screen wrapped outside the well pipe, the bottom end of the siphon branch pipe is provided with the filter which is placed in water and is not easy to block; the filter screen can be a 300-mesh or denser filter screen, and the filtering effect is good; the filter screen can also be cleaned and replaced, and the filtering effect is reliable.
5. The invention adopts two measures of water injection, air exhaust and air collection in the air collection tank, maintains normal long-time operation of siphon, reduces the risk of siphon flow cutoff, reduces the frequency of siphon restart and is convenient for maintenance of the precipitation process.
Drawings
FIG. 1 is a schematic plan view of a foundation pit parallel siphon water lowering device;
FIG. 2 is a siphon start schematic diagram of a foundation pit parallel siphon water lowering device;
FIG. 3 is a schematic view of a vapor collection canister;
FIG. 4 is a schematic diagram of a precipitation process of a foundation pit parallel siphon precipitation device;
FIG. 5 is a schematic plan view of the foundation pit parallel siphon dewatering devices with two sets of dewatering wells distributed in a staggered manner;
FIG. 6 is a schematic structural view of a semi-closed check valve;
FIG. 7 is a schematic plan view of a first positioning element and a second positioning element of the semi-closed check valve;
fig. 8 is a schematic view of the open (a) and closed (b) states of the semi-closed check valve.
The reference numbers in the figures are as follows: the device comprises a water collecting well 1, a dewatering well 2, a siphon pipe 3, a siphon main pipe 31, a siphon branch pipe 32, a check valve 33, a filter 34, a drainage device 4, a water pump 41, a water collecting pit 42, a drainage ditch 43, an exhaust device 5, a water injection valve 51, a pressure water source 52, a gas collecting tank 6, an air inlet bottom valve 61, an exhaust top valve 62, a water injection side valve 63, a water flow direction 7, a liquid level 8, a valve body 331, a valve plate 332, a first positioning member 333, a second positioning member 334, a guide rod 335, a first valve port 336 and a second valve port 337.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. The technical characteristics in the embodiments of the invention can be correspondingly combined on the premise of no mutual conflict.
In the description of the present invention, it should 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 to the other element, i.e., intervening elements may be 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 is to be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature.
In a preferred embodiment of the invention, as shown in fig. 1, a siphon water-lowering device for foundation pit parallel connection is provided, the basic components of which comprise a water-collecting well 1, a siphon pipe network 3, a water-discharging device 4, a water-filling air-discharging device 5 and a gas-collecting tank 6, and the siphon water-lowering device for foundation pit parallel connection is mainly used for synchronously carrying out water-lowering treatment on a plurality of water-lowering wells 2 in the foundation pit.
It should be noted that the specific arrangement site 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 can be adjusted according to the related existing specifications and actual engineering needs, which are not described again. In this embodiment, the dewatering well 2 is excavated at the side of the foundation pit, and the depth of the dewatering well is determined according to the requirement of the foundation pit dewatering. Need not to place the water pump in the precipitation well 2, as long as satisfy the water demand of intaking, the diameter can be less than conventional precipitation well. The water collecting well 1 can be dug independently at the side part of the foundation pit and has the function of making height difference and collecting the underground water in each dewatering well 2 by using the siphon principle. The water collecting well 1 is deeper and larger in diameter than the dewatering well 2, and water level difference of siphon operation and convenience of temporary water storage are guaranteed. Of course, if there is a corresponding sump well 1 in the actual foundation pit engineering itself, it is also not necessary to separately excavate. As shown in fig. 2, the siphon network 3 includes a main siphon pipe 31 and a plurality of branch siphon pipes 32. The main siphon pipe 31 serves as a main pipe section of the entire siphon network 3 for collecting the siphon branch pipes 32. The siphon main pipe 31 may be disposed on the ground beside the foundation pit where each dewatering well 2 is located, and the path of the siphon main pipe should be as close as possible to the disposition site of each dewatering well 2 to avoid the flow resistance caused by the excessively long pipe pass. For convenience of description, the two pipe ends of the siphon main pipe 31 are referred to as a first end portion and a second end portion of the siphon main pipe 31, respectively. The first end of the siphon main pipe 31 is connected with the water injection and exhaust device 5, and the siphon main pipe 31 passes through the wall of the water collecting well 1 from the side part and then extends downwards along the depth direction of the water collecting well 1 through a bend, so that the second end of the siphon main pipe extends below the liquid level of the water collecting well 1. In order to ensure reliability, the level of the second end of the siphon main pipe 31 should be as lower as possible than the bottom level of the dewatering well 2. Each siphon branch pipe 32 corresponds to one dewatering well 2, namely, each dewatering well 2 is connected with the siphon main pipe 31 through one siphon branch pipe 32. Similarly, for ease of description, the two pipe ends of the siphon leg 32 will be referred to as the first end and the second end of the siphon leg 32, respectively. The first end of the siphon branch pipe 32 is connected with the siphon main pipe 31, the second end extends 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 for secondary impurity removal and filtration of underground water in the well entering the siphon branch 32. And the check valve 33 is a check valve for controlling the water in the siphon branch pipe 32 to flow into the siphon main pipe 31 in a single direction but not flow into the dewatering well 2 in a reverse direction. The check valve 33 is provided in the present invention in order to keep the siphon leg 32 full of water during the siphon start-up phase.
The specific structure of the filter 34 in the present invention is not limited, and is based on the ability to trap silt in water. Considering the reliability and cost problems in engineering applications, as an implementation form of the embodiment of the present invention, the filter 34 may be composed of a framework and a filter screen, the framework may be a cylinder with a top opening and a bottom sealing, and the filter screen is wrapped around the outer sidewall and the bottom surface of the framework to form a filtering structure for filtering sediment. If the bottom port of the check valve 33 is not connected with an external pipeline, the whole filter 34 cylinder is wrapped at the bottom port of the check valve 33, and if the bottom port of the check valve 33 is connected with an external pipeline, the whole filter 34 cylinder is wrapped at the opening of the external pipeline of the check valve 33. In order to ensure the reliability of silt filtration, the filter screen needs to be 300 meshes or more. Therefore, except for the filter screen wrapped outside the common dewatering well casing, the invention realizes double filtration by arranging the filter with a denser filter screen at the bottom end of the siphon branch pipe, better avoids the loss of water and soil, and is convenient to clean and replace when the filter is blocked.
In addition, because the siphon operation in-process, the water in siphon pipe network 3 is in the negative pressure state, and the lift is higher, and the negative pressure is big more. The water contains a large amount of air, and the air is precipitated from the water under a negative pressure state to form bubbles. The accumulation of these bubbles can break the siphon effect and therefore require venting measures.
In the embodiment of the invention, the gas collecting tank 6 is arranged on the siphon main pipe 31 to realize gas exhaust. As shown in fig. 4, the bottom, top and sides of the vapor collection canister 6 are provided with openings, respectively, referred to as bottom, top and side openings, respectively, for ease of description. And an air inlet bottom valve 61, an exhaust top valve 62 and a water injection side valve 63 for controlling the opening and closing of the openings are respectively arranged on the bottom opening, the top opening and the side opening. The gas collection tank 6 is arranged at the front end position of the siphon main pipe 31 before penetrating through the wall of the water collecting well 1, and the highest water injection level allowed by the water collecting well 1 is higher than the top of the gas collection tank 6. In order to ensure the gas collection effect, the siphon main pipe 31 between the water injection and exhaust device 5 and the gas collection tank 6 is obliquely arranged with the elevation gradually increased, and the gas collection tank 6 is communicated with the highest elevation position of the siphon main pipe 31 through the bottom opening where the air inlet bottom valve 61 is positioned. That is, the siphon main pipe 31 has a certain arrangement gradient, the elevation of the end portion of the siphon main pipe 31 connected to the water filling and exhausting device 5 is the lowest, and the elevation of the position of the siphon main pipe 31 connected to the gas collecting tank 6 is the highest, so that when there is a bubble in the siphon main pipe 31, the siphon main pipe will move to the position of the gas collecting tank 6 by itself, and therefore, after the gas in each siphon branch pipe 32 enters the siphon main pipe 31, the gas will be gathered to the highest position of the siphon main pipe 31 along the water flow, and will be gathered to the gas collecting tank 6 in the state that the air inlet bottom valve 61 is opened, thereby avoiding damage to the siphon.
The air inlet bottom valve 61, the exhaust top valve 62 and the water injection side valve 63 in the gas collecting tank 6 can respectively adopt different opening and closing combinations at different stages. During normal gas collection, 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 as to maintain the top of the main siphon pipe 31 in a bubble-free state. When the air bubbles in the gas collecting tank 6 are close to full, the air inlet bottom valve 61 needs to be closed, the exhaust top valve 62 needs to be opened, then the water injection side valve 63 is connected with the external water injection pipe, the water injection side valve 63 is opened, water is injected into the gas collecting tank 6 for exhaust, the gas collecting tank 6 is filled with water again, and then normal gas collection is continued. Of course, the exhaust of the gas collection tank 6 can be controlled manually or automatically. The automatic control can be equal-interval automatic control with reasonable time intervals set according to the actual gas collection condition, and can also adopt a sensor to detect the water level in the gas collection tank and realize intelligent automatic control according to the water level condition.
The water injection and air exhaust device 5 at the end of the siphon main pipe 31 functions to inject water under pressure into the siphon main pipe 31, and assist in discharging bubbles in the siphon main pipe 31 by a high-speed water flow, or assist in introducing bubbles in the siphon main pipe 31 into the gas collection tank 6. Because of the viscous resistance to the bubbles on the inner wall of the siphon main pipe 31, in the case of a small height difference, the flow rate of the water generated by the siphon may not be sufficient to allow all the bubbles to be discharged from the second end of the siphon main pipe 31 or to smoothly flow into the gas collecting tank 6 through the water flow. Therefore, if necessary, the siphon main pipe 31 may be filled with water under pressure, and the external water source having a high head pressure may be used to increase the flow rate of the water in the siphon main pipe, thereby removing bubbles attached to the wall of the siphon main pipe. The entrained gas bubbles are partly carried directly into the sump 1 and possibly partly into the gas collection tank 6.
As an implementation form of the embodiment of the present invention, the water injection and air exhaust device 5 includes a pressure water source 52 and a water injection valve 51, an outlet of the pressure 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 on-off of a water path between the pressure water source 52 and the siphon main pipe 31. When the water filling and air exhausting operation is required, the water filling valve 51 between the pressure water source 52 and the siphon main pipe 31 can be opened to introduce the high-pressure water into the siphon main pipe 31.
The pressure water source 52 of the air discharge device may be tap water with water pressure, or other water sources on site, and if the pressure required for bringing out the air bubbles in the pipe is not sufficient, the pressure may be increased by a water pump or the like and then introduced into the main siphon pipe 31.
In addition, the water accumulated in the water collecting well 1 needs to be discharged outside through the drainage device 4, and the liquid level height in the water collecting well 1 needs to be regulated and controlled according to the actual precipitation requirement. When siphon precipitation is carried out, the liquid level in the water collecting well 1 is required to be lower than that in the precipitation well 2, and the larger the height difference between the two is, the larger the siphon precipitation speed is. Therefore, the drainage means 4 may be provided as a device capable of controlling the amount of water to be drained so as to change the liquid level in the sump 1 by the difference in the amount of inflow and outflow water.
As an implementation form of the embodiment of the present invention, the drainage device 4 includes a water pump 41, a water collection pit 42 and a drainage ditch 43. Wherein the water pump 41 is provided with a flexible output pipe besides 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 extends into a water collecting pit 42 connected with a drainage ditch 43, and is used for pumping the water collected in the water collecting well 1 into the water collecting pit 42 and discharging the water out through the drainage ditch 43. The purpose of the sump 42 is to prevent the drainage ditch 43 from being clogged, and to prevent the external environment from being adversely affected, in order to perform sedimentation of silt in advance before drainage. To reduce impact, the bottom of the sump 42 may be paved with a layer of pebbles or cured with concrete.
The siphon network 3 is empty of water in the initial state, and therefore, it is necessary to start up water injection in advance to form a siphon effect of automatic water discharge. The water in the siphon network 3 is poured into the sump 1 to reversely fill the main siphon pipe 31 and the branch siphon pipes 32. Generally, if the diameters of the main siphon pipe 31 and the branch siphon pipes 32 are large, the full flow of water will not be formed in the pipes during the water filling process, and the air in the pipes can be normally discharged through the space above the pipes, so that the water gradually replaces the air in the pipes. However, in actual use, the pipe diameter of the siphon pipe network 3 is adjusted according to the need of precipitation, and a pipe with a smaller pipe diameter may be adopted in order to ensure the formation of siphon effect. In particular, for the siphon branch 32, most practical projects often use only about 2cm of thin pipe. For such thin pipes, a full pipe flow is often formed when the water in the collector well 1 is pressed into the pipe network. At this time, if air still exists in the lower portion of the siphon branch pipe 32 and the top portion of the siphon branch pipe 32 is filled with water, the air in the siphon branch pipe cannot be discharged automatically due to the one-way 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 an implementation form of the embodiment of the present invention, the check valve 33 is designed as a semi-hermetic 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 body 331 has a hollow flow passage therein, and a first valve port 336 and a second valve port 337 communicating the flow passage in the valve body 331 are provided at both ends of the valve body 331, respectively. 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 has a valve seat, the position of the valve seat is a step surface, and the cross section of the upper flow passage is larger than that of the lower flow passage. The valve plate 332 functions as a valve core in the valve, and can cooperate with a valve seat to perform an opening and closing control function of the valve under the cooperation of the guide rod 335, the first positioning member 333 and the second positioning member 334. Specifically, the first positioning member 333 and the second positioning member 334 are disposed in parallel on two cross sections in the inner cavity of the valve body and located on two 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. Guide rod 335 vertically passes through the center of valve plate 332 and is coupled and fixed with valve plate 332, and guide rod 335 is arranged along the inner flow path axis of valve body 331, so that valve plate 332 is perpendicular to the inner flow path axis of valve body 331. The two ends of the guide rod 335 respectively form a sliding pair with the first positioning part 333 and the second positioning part 334 for ensuring the guide rod 335 to move along the axial direction. Specifically, as shown in fig. 7, the first positioning element 333 and the second positioning element 334 are both water-permeable disks with guiding holes formed in the centers thereof, the outermost portion of each disk is a same outer circular ring matched with the cross section, an inner circular ring is arranged in the center of the outer circular disk, the center of the inner circular ring is used as the guiding hole, and the inner circular ring is supported on the outer circular ring of the disk through three supporting rods which form an angle of 120 degrees with each other. The outer diameter of the guide rod 335 is slightly smaller than the diameters of the upper and lower guide holes, and two ends of the guide rod 335 penetrate into the two guide holes of the first positioning part 333 and the second positioning part 334 respectively to form a guide mechanism. The valve plate 332 and the valve seat form an opening and closing mechanism guided by the 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 away from the valve seat, and the flow passage in the valve is opened; when fluid flows from the second port 337 to the first port 336, the valve plate 332 is pushed to be pressed on the valve seat, and the flow passage in the valve is closed. The semi-closed check valve is different from a common check valve in that a valve plate 332 is the biggest difference, a plurality of air-permeable micro-permeable capillary holes are formed in the valve plate 332 of the semi-closed check valve, the reverse flow of water can be effectively prevented through the semi-closed check valve, air with certain pressure is allowed to freely flow, and the water injection and air exhaust efficiency is improved when full pipe flow occurs in the pipe. In practical application, the diameter of the capillary hole is generally below 1mm, so as to realize the effect of air permeability and micro water permeability. The air-permeable and micro-permeable valve is used for allowing air to pass through capillary holes, but water bodies preferably do not pass through the valve, that is, the valve plate ideally allows air to pass through and does not allow water to pass through, but in practical application, water does not need to be absolutely prevented from flowing through, and if some water bodies pass through, the functional effect of the invention is not significantly influenced.
When the semi-closed check valve is adopted, even if full pipe flow occurs at the top of the siphon branch pipe 32 in the siphon starting process, air at the lower part of the siphon branch pipe 32 is compressed to a certain pressure and then is discharged through the capillary holes in 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 a siphon function are ensured.
In addition, it should be noted that, only one set of dewatering wells 2 at the bottom of the foundation pit may be provided in the invention, or the dewatering wells may be grouped, for example, into 2 or more sets. As shown in fig. 5, two sets of dewatering wells 2 are taken as an example, and each set of dewatering well 2 is provided with a single siphon network 3, a water injection and air exhaust device 5 and a gas collection tank 6. When more than one group, if the siphon of a certain group of precipitation well 2 is invalid, the siphon of other groups of precipitation well 2 can still normally operate, so that the precipitation effect of the whole foundation pit is prevented from being invalid at once, and the maintenance time is strived for.
Therefore, the foundation pit parallel siphon precipitation device can be used for foundation pit side precipitation, as the precipitation wells are communicated through the siphon pipes, the water level elevations of the precipitation wells are close, the effect of simultaneously controlling a plurality of precipitation wells can be achieved only by controlling the water pumps in the water collecting wells and monitoring the water level of one of the precipitation wells, and the precipitation control complexity is reduced.
In order to better understand the concrete precipitation control process of the invention, a foundation pit parallel siphon precipitation construction method is further provided based on the foundation pit parallel siphon precipitation device.
In a preferred embodiment of the present invention, a foundation pit parallel siphon precipitation construction method based on the foundation pit parallel siphon precipitation device includes the following steps:
s1, excavating a precipitation well 2 in a foundation pit to be subjected to precipitation, 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 collecting tank 6 to form the foundation pit parallel siphon precipitation device.
It should be noted that the construction of dewatering wells, collecting pits and drainage ditches can refer to the prior art, and the specific excavation size and the specific excavation mode can be adjusted according to the actual engineering condition. 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 specific connection forms are not described again. During construction, the siphon main pipe 31 can be horizontally arranged near the 2 mouths of each dewatering well, 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 well wall of the water collecting well 1 and bends for 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 dewatering process. The gas collecting tank is arranged on the siphon main pipe 31 close to the water collecting well 1, and the siphon main pipe 31 keeps a small gradient horizontally through erecting a support or filling soil on the lower part, so that the elevation of the position where the gas collecting tank 6 is arranged is the highest, and bubbles can enter the gas collecting tank 6. The gap of the siphon main pipe 31 penetrating through the wall of the water collecting well 1 needs to be sealed by glass cement, and a water leakage prevention measure is made. The exhaust device 5 is in a normally closed state and is opened only when exhaust is required. 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 a 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 a bottom pipe opening needs to be positioned below the lowest precipitation height during pipe sinking, so that the pipe opening can be positioned in water in the whole precipitation process. A submersible pump in the drainage device 4 is installed in the sump 1, and an output pipe for drainage is connected to the sump 42, and a water level control device is also installed in the sump 1, so as to realize automatic control.
S2, opening an air inlet bottom valve 61 and an air exhaust top valve 62 of the air collecting tank 6, and closing a water injection side valve 63 of the air collecting tank 6; 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 main siphon pipe 31, so that the water in the water collecting well 1 flows into the main siphon pipe 31 and further flows into each branch siphon pipe 32, and the valve sheet 332 in the check valve 33 at the tail end of each branch siphon pipe 32 is pressed on the valve seat under the pressure in the pipe, so that the flow channel 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 air in the siphon pipe network 3 is driven by the water flow to be discharged from the check valve 33 at the bottom end of the siphon branch pipe 32, and a part of the air is reversely upwards collected in the gas collecting tank 6 through the siphon pipe network 3 and discharged from the exhaust top valve 62 of the gas collecting 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, the exhaust top valve 62 of the gas collecting tank 6 is closed at this time, and the siphon pipe network 3 completes the water injection to form siphon.
S3, after the siphon pipe 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 automatically flows into the water collecting well 1 through the siphon principle. The water discharged to the sump 42 is precipitated and discharged to the outside through the drainage ditch 43.
In the siphon precipitation process, water level control and siphon operation control need to be executed.
The water level is controlled as follows:
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 adjusted by controlling the flow of the water pump 41, and then the precipitation depth in each precipitation well 2 is controlled to meet the design requirement. Specifically, after precipitation starts, along with the falling of 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 through the siphon principle, and the precipitation process is related to the flow of the water pump. When the flow of the water pump is small, the water level in the water collecting well descends slowly, the water level height difference of the dewatering well and the water collecting well is small, the siphon flow rate is slow, the water level in each dewatering well descends slowly and is stabilized at the certain depth, the designed dewatering depth can not be reached, and the water pump with large flow needs to be used instead. When the flow of the water pump is large, the water level in the water collecting well descends fast, the siphon flow speed is accelerated along with the increase of the height difference of the water levels of the dewatering wells and the water collecting well, water in each dewatering well quickly flows into the water collecting well, after the water level of each dewatering well reaches the designed depth reduction, the water pump is stopped to drain, and after the water level of each dewatering well is restored to the set water level, the water pump is started to drain, and the operation is repeated. The water level depth can be monitored by the automatic water level control system, and the automatic opening and stopping of the water pump are controlled. The water pump with proper flow is selected, the start-stop period of the water pump can be shortened, and the service life of the water pump is prolonged.
Siphon operation was controlled as follows:
in the siphon operation process, 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 the air is precipitated from the water under a negative pressure state to form bubbles. When the flow rate is fast, the bubbles are taken away with the water flow, but when the water flow is slow, the bubbles are accumulated at the top of the siphon tube, the bubbles are accumulated more, the flow rate is affected, and if the bubbles are accumulated more, the flow cutoff is caused. After the flow is cut off, the siphon needs to be restarted to continue the precipitation. Therefore, to ensure the normal operation of the siphon, two measures are taken: 1. the gas collection function is adjusted by switching the valve of the gas collection tank through the gas collection of the gas collection tank arranged at the highest point of the siphon main pipe; 2. the exhaust device injects large-flow pressure water into the siphon main pipe at regular time to form water flow with certain flow rate and take away bubbles gathered in the siphon main pipe. Therefore, the concrete control modes of the two measures during actual construction are as follows:
in the siphon precipitation process, the air inlet bottom valve 61 on the air collecting tank 6 is initially kept in an open state, and the water injection side valve 63 and the exhaust top valve 62 are kept in a closed state, so that bubbles in the pipe are continuously collected into the air collecting tank 6 along with the flow of water. When the space occupied by the air in the air collecting tank 6 reaches a set value, closing the air inlet bottom valve 61 of the air collecting tank 6, and disconnecting the air collecting tank 6 and the siphon network 3, wherein the set value can be generally set to be that the tank is basically filled with air; then, opening an exhaust top valve 62 of the gas collecting tank 6, and injecting water into the gas collecting tank 6 through a water injection side valve 63 to replace the internal air; after the gas collecting tank 6 is filled with water, the water filling side valve 63 and the exhaust top valve 62 are closed, the air inlet bottom valve 61 is opened again to communicate the gas collecting tank 6 with the siphon network 3, and the gas collecting function of the gas collecting tank 6 is recovered.
In the siphon precipitation process, the water injection and exhaust device 5 runs regularly, the flow velocity of water in the siphon main pipe 31 is improved through pressure water, and bubbles which are gathered at the top of the inner pipe wall of the siphon main pipe 31 and influence the normal operation of siphon are taken away. The specific operation time of the water injection and air exhaust device 5 can be determined according to the accumulation condition of the bubbles in the pipe, and the operation interval can be optimized according to the actual condition.
And S4, after precipitation is finished, recovering 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 precipitation well 1 to complete the whole precipitation construction process.
In addition, it should be noted that, in the siphon precipitation process, if the filter 34 is clogged, the filter 34 needs to be taken out and the filter screen needs to be cleaned or replaced, and then the filter 34 is replaced to the original position again, and S2 is executed again to restart the siphon to continue the siphon precipitation.
The above-described embodiments are merely preferred embodiments of the present invention, which should not be construed as limiting the 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, the technical scheme obtained by adopting the mode of equivalent replacement or equivalent transformation is within the protection scope of the invention.
Claims (10)
1. A foundation pit parallel siphon precipitation 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) which are used for synchronously carrying out precipitation treatment on a plurality of precipitation wells (2) in a foundation pit;
the siphon pipe network (3) comprises a siphon main pipe (31) and a plurality of siphon branch pipes (32); the siphon main pipe (31) is arranged on the ground beside a foundation pit 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) is positioned below the liquid level of the water collecting well (1) after penetrating through the well wall of the water collecting well (1); each siphon branch pipe (32) corresponds to one dewatering well (2) respectively, the first end part of each siphon branch pipe (32) is connected with the main siphon pipe (31), and the second end part of each siphon branch pipe 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 the 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 into the siphon main pipe (31) in a one-way mode but not flow into the dewatering well (2) in a reverse direction;
the bottom, the top and the side part of the gas collection tank (6) are respectively provided with an opening, and an air inlet bottom valve (61), an exhaust top valve (62) and a water injection side valve (63) for controlling the opening to be opened and closed are respectively arranged on the openings; the gas collection tank (6) is arranged at the position where the main siphon pipe (31) penetrates through the front end of the well wall of the water collecting well (1), and the highest water injection level allowed by the water collecting 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 obliquely arranged in an increasing height manner, the gas collection tank (6) is communicated with the highest height position of the siphon main pipe (31) through the bottom opening of the gas 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 bubbles in the auxiliary siphon main pipe (31) are discharged from the second end part or enter the gas collecting tank (6) along with high-speed water flow;
the drainage device (4) is used for discharging water accumulated in the water collecting well (1).
2. A foundation pit parallel siphon water lowering device according to claim 1, characterized in that the water injection and exhaust device (5) comprises a pressure water source (52) and a water injection valve (51), wherein the outlet of the pressure water source (52) is connected with the first end of the siphon main pipe (31), and the water injection valve (51) is used for controlling the on-off of the water path between the pressure water source (52) and the siphon main pipe (31).
3. The foundation pit parallel siphon water lowering device according to claim 1, wherein the check valve (33) is a semi-closed check valve, and comprises a valve body (331), a valve plate (332), a first positioning member (333), a second positioning member (334) and a guide rod (335); a first valve port (336) and a second valve port (337) which are communicated with a flow channel in the valve body (331) are respectively arranged at two ends of the valve body (331), 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 penetrates 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 with the first positioning piece (333) and the second positioning piece (334) for ensuring that the guide rod (335) moves along the axial direction; 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 flow passage in the valve 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 channel in the valve is closed; capillary holes with the diameter not more than 1mm are formed in the valve plate (332).
4. A foundation pit parallel siphon water lowering device according to claim 3, characterized in that the first positioning member (333) and the second positioning member (334) are both water permeable discs with a guide hole at the center, and two ends of the guide rod (335) respectively penetrate into the two guide holes to form a guide mechanism.
5. The foundation pit parallel siphon water lowering device as claimed in claim 1, wherein the filter (34) comprises a framework and a filter screen, and the filter screen is sleeved around the framework to form a filter structure wrapping the valve port of the check valve (33).
6. A foundation pit parallel siphon water lowering device according to claim 1, characterized in that the water draining device (4) comprises a water pump (41), a water collecting pit (42) and a water draining ditch (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 extends into a water collecting pit (42) connected with a drainage ditch (43) and is used for pumping the water collected in the water collecting well (1) into the water collecting pit (42) and discharging the water out through the drainage ditch (43).
7. A foundation pit parallel siphon water lowering device according to claim 1, characterized in that all the water lowering wells (2) in the foundation pit are divided into a plurality of groups, and each group of water lowering wells (2) is provided with a single set of siphon pipe network (3), water injection and air exhaust device (5) and air collecting tank (6).
8. The foundation pit parallel siphon precipitation device of claim 5, wherein the filter screen is 300 meshes or more.
9. A foundation pit parallel siphon dewatering construction method based on the foundation pit parallel siphon dewatering device as claimed in claim 3, characterized by comprising the following steps:
s1, excavating a precipitation well (2) in a foundation pit to be subjected to precipitation, excavating a water collecting well (1), a water collecting pit (42) and a drainage ditch (43) on the outer side of 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 collecting tank (6) to form the foundation pit parallel siphon precipitation device;
s2, opening an air inlet bottom valve (61) and an air exhaust top valve (62) of the air collecting tank (6), and closing a water injection side valve (63) of the air collecting 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 main siphon pipe (31), so that the water in the water collecting well (1) flows into the main siphon pipe (31) and further flows into each branch siphon pipe (32), and a valve plate (332) in a check valve (33) at the tail end of each branch siphon pipe (32) is pressed on the valve seat under the pressure in the pipe, so that a flow passage in the valve is closed; in the water injection process, 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 driven by water flow to be discharged from a check valve (33) at the bottom end of the siphon branch pipe (32), and the other part of the original air is reversely upwards collected in the gas collecting tank (6) through the siphon pipe network (3) and discharged from an exhaust top valve (62) of the gas collecting 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), the exhaust top valve (62) of the gas collecting tank (6) is closed at the moment, and the siphon pipe network (3) completes the water injection to form siphon;
s3, after the siphon pipe network (3) is filled with water, starting a water pump (41) in the water collecting well (1), continuously discharging the water in the water collecting well (1) into a water collecting pit (42), when the water level of the water collecting well (1) is lowered to be lower than the water level of any dewatering well (2), automatically flowing the water in the corresponding dewatering well (2) into the water collecting well (1) through a siphon principle, discharging the water in the water collecting pit (42), and discharging the water through a drainage ditch (43) after sedimentation;
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 adjusted by controlling the flow of the water pump (41), and then the precipitation depth in each precipitation well (2) is controlled to meet the design requirement;
in the siphon precipitation process, an air inlet bottom valve (61) on the air collecting tank (6) is initially kept in an open state, a water injection side valve (63) and an exhaust top valve (62) are kept in a closed state, and bubbles in the pipe are continuously collected into the air collecting tank (6) along with the flow of water flow; when the space occupied by the air in the air collecting tank (6) reaches a set value, closing an air inlet bottom valve (61) of the air collecting tank (6), disconnecting the air collecting tank (6) and a siphon pipe network (3), then opening an exhaust top valve (62) of the air collecting tank (6), and injecting water into the air collecting tank (6) through a water injection side valve (63) to replace the air inside; after the gas collecting tank (6) is filled with water, the water injection side valve (63) and the exhaust top valve (62) are closed, the air inlet bottom valve (61) is opened again, the gas collecting tank (6) and the siphon network (3) are communicated, and the gas collecting function of the gas collecting tank (6) is recovered;
in the siphon precipitation process, the water injection and air exhaust device (5) runs regularly, the flow velocity of water in the siphon main pipe (31) is improved through pressure water, and bubbles which are gathered at the top of the inner pipe wall of the siphon main pipe (31) and influence the normal operation of siphon are taken away;
and S4, after precipitation is finished, recovering 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 water collection well (1).
10. The foundation pit parallel siphon precipitation construction method according to claim 9, characterized in that in the siphon precipitation process, if the filter (34) is blocked, the filter (34) needs to be taken out for cleaning or replacing the filter screen, then the filter (34) is replaced to the original position again, S2 is executed again to restart the siphon, and siphon precipitation is continued.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210962959.8A CN115162388B (en) | 2022-08-11 | 2022-08-11 | Foundation pit parallel siphon dewatering device and dewatering construction method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210962959.8A CN115162388B (en) | 2022-08-11 | 2022-08-11 | Foundation pit parallel siphon dewatering device and dewatering construction method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115162388A true CN115162388A (en) | 2022-10-11 |
| CN115162388B CN115162388B (en) | 2023-10-31 |
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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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| CN115162388B (en) | 2023-10-31 |
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