JP2003328344A - High lift wellpoint apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform water collection through wellpoints, and pumping action by easily constructing a pumping apparatus in using a high lift wellpoint construction method. <P>SOLUTION: A casing pipe 10 of prescribed length is disposed inside a hole 5 excavated deep from the ground, and the wellpoints 13 are provided at riser pipes 12 provided at the lower end of the casing pipe 10. A filter medium 6 such as sand is filled in the hole 5 to construct a permeable layer, and water is collected into the pipe 10 through the wellpoints 13 by negative pressure applied to the pipe 10, and collected into a separate tank 20 by a high lift pump 15 provided inside the casing pipe 10. A means for applying negative pressure to each of the tank 20 and pipe 10 is composed of a vacuum pump 28 in an exhaust system 25. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water pumping device used for lowering the groundwater level in an excavated portion when constructing an underground portion such as a building structure, and particularly from a deeply buried hole.
The present invention relates to a device configured to be capable of pumping water with a stage pump.

[0002]

2. Description of the Related Art When excavating a ground having a high groundwater level or a soft clay layer to build a foundation of a building,
In order to lower the water level in the ground to be excavated, the well point method is adopted in which deep wells are constructed around the construction ground at regular intervals and pumping groundwater. In the well point method, a large number of wells for pumping water (well point device) are provided so as to surround the periphery of the excavated portion.
Are arranged at predetermined intervals to penetrate deeper than the depth of excavation of the pumping pipe, and a well point having a function of sucking only water is arranged at the tip of the pumping pipe. Then, each of the pumping pipes is connected to a vacuum suction device, and groundwater is sucked by a vacuum pump to lower the groundwater level so that excavation work can be performed in a dry state.
Also, even under the condition that a large amount of fine particles such as silt are mixed in the drainage, there is an advantage that the drainage performance is not deteriorated at the well point, and even in the case of relatively low-grade soil with poor water permeability, The advantage that the groundwater level can be lowered can be exhibited.

[0003]

When the above-mentioned general well point method is used, ground water is pumped up only by vacuum suction, so there is a limit to the theoretical height of pumped water. Considering the water resistance and so on, it is possible to actually drain water to a depth of about 6 to 7 m. Therefore, instead of using only the well point of a simple structure, by arranging the well point provided at the lower end of the casing pipe, and by arranging the pumping pump at the bottom of the casing pipe, it is possible to pump water from a deeper position, It has been proposed to enable deep drilling.
However, even when constructing a pumping system using the deep well point, the pumping performance by the pump is determined by the opening ratio of the well point strainer and the pumping performance of the pump. It is greatly affected by the aperture ratio.

The present invention eliminates the drawback of the conventional well point of large depth and can be easily applied to the soil ground having a relatively low hydraulic conductivity, and efficiently lowers the groundwater level in the construction of deep excavation. The purpose is to provide a method of obtaining.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a water pumping apparatus which is constructed by arranging a large number at predetermined intervals so as to surround a construction area for deeply excavating the ground. The invention according to claim 1 of the present invention is the riser, wherein the pumping device is provided with a downhole to be constructed underground, a casing pipe installed inside the downhole, and a well point for connecting a plurality of well pipes to the lower portion of the casing pipe. A pipe, a filter material filling the casing pipe and the riser pipe and the periphery of a well point in the downhole, and a sealing member provided on the upper portion of the casing pipe and on the upper portion of the filter material, respectively. And

The invention of claim 2 is characterized in that, when constructing the water pumping device, a layer of a filter material having large water permeability is provided around the casing pipe and the riser pipe installed in the downhole.

According to the invention of claim 3, when the downhole is excavated with muddy water and the casing pipe and the well point are installed inside the downhole, when the filter material is constructed, the muddy water in the hole is removed. By replacing with clean water and sand,
It is characterized in that a filter layer having good water permeability can be constructed.

According to a fourth aspect of the invention, an exhaust system is connected to the casing pipe and a separate tank for temporarily storing water pumped by a pump, and the exhaust system applies a negative pressure to the inside of the casing pipe. It is characterized in that it is provided and used for separating steam and water in a separate tank.

The invention of claim 5 is characterized in that a pumping pump is arranged inside the casing pipe, water is collected by the pumping pump through a pumping pipe into a separate tank, and separated into steam and discharged.

According to a sixth aspect of the present invention, a negative pressure is constantly applied to the casing pipe by a means for applying a negative pressure so that water is collected through a well point, and the water is pumped by the water pump. It is characterized by doing.

Due to the above-mentioned configuration, the present apparatus can be used even in a construction site where a deep underground is excavated.
The effect of lowering the groundwater level can be favorably performed without imposing a heavy load on the pumping pump. When constructing the water pumping apparatus, it is possible to use the same construction method as in the conventional well point, and it is possible to easily perform excavation at a large depth and install the apparatus. In addition, even if the well point is installed at a deep position, the sand filter material filling the inside of the downhole can separate and discharge only the water in a state where the fine particles of the soil are filtered, which also imposes a burden on the ground facility. Can be reduced. Furthermore, when a means for constantly applying a negative pressure to the casing pipe is used, the load on the pumping pump can be reduced and the operating time of the pump can be shortened, so that the energy used can be reduced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The high-lift pumping apparatus according to the present invention will be described with reference to the illustrated example. The example shown in FIG.
The structure of the pumping device 4 is shown, and the casing pipe 10 having one or a plurality of riser pipes 12 ... Attached at the bottom is set up in the downhole 5 excavated from the construction ground 1 to a predetermined depth. The pumping member is constructed and the pumping pump 15 installed at the lower part of the casing pipe 10 pumps water. At the lower part of the riser pipe 12 connected to the lower part of the casing pipe 10, as in the case of a general well point device, a well point 13 made of a water permeable member that allows water to pass but can separate sand or the like is provided. The ground water is collected through the filter material 6 formed around the casing pipe 10.

The pumping pump 15 arranged below the casing pipe 10 is a submersible pump. A pumping pipe 16 is connected to the pumping pump 15 for draining to the ground, and water is collected in a separate tank 20 for draining pipe 22. Drain from. It should be noted that the casing pipe 10 can be of any length and has a digging depth of 30 m, for example.
At the construction site, the casing pipe should be 25 ~ 3
It is also possible to use a 0 m long pipe, provide a riser pipe and a well point in combination at the lower end thereof, and drain the water to the ground by the pump 15.

In the water pumping device 4, a sealing material 7 is provided on the upper part of the downhole 5 with clay or the like to prevent air from entering from the ground, and a lid member 11 is arranged on the upper part of the casing pipe 10. The pumping pump 15 draws water from the atmosphere to shut down the pressure inside the casing pipe 10. An intake pipe 26 of an exhaust system 25 is connected to the upper portion of the casing pipe 10, and the air inside the casing pipe 10 is sucked by a vacuum pump 28, so that the casing pipe 1
The pressure inside 0 is kept lower than the atmospheric pressure. Then, the negative pressure applied to the casing pipe 10 assists the action of collecting water into the casing pipe 10 through the well point 13 so that the action of pumping up groundwater can be performed in a good state. The operation of applying a negative pressure to the casing pipe 10 by the exhaust system 25 is performed via the valve 26a. The operation of applying a negative pressure to the pipeline of the exhaust system and the separate tank 20 is performed by using each valve. So that it can be done at any time.

In the above-ground equipment installed in the water pumping device 4, a separate tank 2 having a drainage pump 21 inside is installed.
0, the pipe 18 from the casing pipe 10 ...
And the pumping pipe 16 of each casing pipe 10 ...
Are connected via an on-off valve 17 ...
The operation to pump up the water inside is performed at any time. Then, the pumping pump 15 arranged in the casing pipe 10 pumps the internal water and discharges it toward the separate tank 20, thereby causing a negative pressure to act on the inside of the casing pipe 10 and the well point 13 Collect water in the casing pipe 10 through. The water pumped up from the casing pipe 10 by the pump 15 is the drainage pump 2 arranged in the separate tank 20.
Although it is discharged from the drainage pipe 22 by 1, the separation tank 20 separates mud, fine sand, etc. from the pumped water and drains it. Also, the casing pipe 1
If the water pumped from 0 cannot be completely separated from the mud and the like in the separate tank 20, the water is sent from the drain pipe 22 to the tank or pool of the sedimentation facility to secondarily separate the mud and the like. Waste water should be treated.

An exhaust system 25 is provided in combination with the drainage system of the pumping device 4. In the exhaust system 25, the pipe line connected to the vacuum pump 28 is connected to the exhaust pipe 27 of the separate tank 20 and the casing pipe 10. Suction tube 2
6 ... are connected via open / close valves 26a and 27a, respectively. Then, by sucking the air inside the separate tank 20, the pressure inside the separate tank 20 is reduced, and the air discharged together with the water from the inside of the casing pipe 10 is separated and discharged. Assist the pumping action. Further, by sucking the air inside the casing pipe 10 to reduce the internal pressure, the action of pumping up the water by the pumping pump 15 and the action of reducing the internal pressure are combined, and the well point 13 It is possible to more effectively exert the action of collecting water from the.

When constructing the above-mentioned pumping apparatus, as shown in FIG. 2, first, a conventionally known excavation device 3 is used, and a diameter (φ) of about 0.3 to 1 m is vertically provided and a depth is set. The downhole 5 of H1 is excavated. The digging depth H1 of the digging hole 5 is formed deeper than the groundwater level to be lowered by the well point, and the extra digging depth is set in the same manner as in the conventional well point. When digging the downhole 5, in the case of sandy ground,
It is possible to excavate using a water jet or the like, but since the diameter of the downhole 5 is large, the surrounding ground may be damaged. Therefore, even in the sandy ground containing a large amount of clay, by using a general excavator 3, a hole is dug down in a state of being filled with muddy water, and the method of removing the excavated soil with muddy water is used to remove the surrounding wall. It is possible to construct the downhole 5 having a predetermined diameter without damaging the hole.

After excavating the downhole 5 as described above, as shown in FIG. 3, a casing pipe 10 having a predetermined number of riser pipes 12 ... The pumping-up device 4 as shown in FIG. 1 is constructed by upsetting and filling a filter material such as sand around it. When constructing the filter material 6, a filter capable of exhibiting uniform water permeability by means of pumping water mixed with sand and injecting it into the gap of the downhole 5 to fill it Build the material 6. As the filter material used for the filter material 6, a material having a larger specific gravity than the particles contained in the muddy water used when excavating the downhole 5 may be selected. Then, while filling the downhole 5 with a filter material, the muddy water used at the time of excavation is replaced with sand, and a uniform water-permeable layer is provided around the casing pipe 10 and the riser pipe 12 installed in the downhole 5. Can be built.

As described above, the casing pipe 10
A filter material 6 having a predetermined thickness is built around the base material, and an impermeable material such as clay is caulked on the upper portion of the filter material 6 to a predetermined thickness, so that the inside of the downhole 5 is exposed to atmospheric pressure. Shut off so that it does not work. The casing pipe 1
As 0, for example, a pipe having an inner diameter of 20 to 50 cm is used, and the riser pipe 12 provided so as to project to the lower portion of the casing pipe 10 is 2.5 to 5.0 cm.
The well point 13 provided at the bottom of each riser pipe 12 has an inner diameter of 1 to 5 m,
The diameter is 5 to 10 cm and the length is 0.5 to 1 m. The opening ratio of the strainer of the well point 13 can be arbitrarily set, but in the well point 13 shown in this embodiment, the layer of the filter material 6 formed around the well point 13 Since fine particles in the ground are not sucked, a mesh having a coarse mesh may be provided so as not to suck sand of the filter material.

When constructing the water pumping device 4 and digging the ground, as shown in FIGS. 4 and 5, the digging hole 5 is drilled around the digging portion 2 and the well row 8 is arranged. In the well row 8, the interval A for excavating the downhole 5 is set to about 3 to 10 m, and each pumping device 4 ...
To collect water in the separate tank 20. Further, in the exhaust system 25, the vacuum pump 28 connected to the separate tank 20 via the exhaust pipe 27 is connected to the exhaust pipe 26 of each casing pipe 10 as shown in FIG. It exerts an action of applying a negative pressure inside the pipe 10 and an action of maintaining the pressure inside the separate tank 20 lower than the atmospheric pressure.

The apparatus shown in the above embodiment can be used to reduce the groundwater level in fine sand or coarse sand layers,
The height that lowers the groundwater level is 10 to 10
It can be about 20 m. Therefore, the depth H1 for excavating the downhole 5 is, in addition to the depth H required for lowering the groundwater level by the well point,
The slope of the drop in the water level around the pumping system is set in consideration of the soil quality of the surrounding ground. Further, in the water pumping device 4, since the casing pipe 10 is given a negative pressure by the exhaust system 25, groundwater is always sucked through the well point 13 and is installed in the lower portion of the casing pipe 10. The pumping pump 15 causes the ground water accumulated inside the casing pipe 10 to be pumped. A high-lift submersible pump is used as the pumping pump 15. When pumping water by the pumping pump 15,
Since only the water accumulated inside the casing pipe 10 is discharged, factors such as the opening ratio of the well point 13 do not have a large effect, and the load on the pumping pump 15 can be reduced.

In the pumping apparatus, the pumping pump 1 has the function of collecting water in the casing pipe 10 and the function of pumping water.
If only 5 is to be loaded, a heavy load will be imposed on the pumping pump 15. That is, the pumping pump 15 bears all the functions of pumping water from the bottom portion of the casing pipe dug to a deep position toward the ground and collecting groundwater in the ground through the well points 13. Is required. in this way,
In order not to put a heavy burden on the pump,
In the present embodiment, if the intake pipe 26 of the exhaust system 25 connected to the vacuum pump 28 is connected to the casing pipe 10 and the vacuum pump 28 applies a negative pressure to the casing pipe 10, Well point 13
From this state, the action of collecting water toward the inside of the casing pipe 10 is constantly provided.

Therefore, the pumping pump 15 only has to bear the operation of only draining the water accumulated in the casing pipe 10 through the pumping pipe 16 at any time, and it is also necessary to use a high-performance pump. Absent. Further, when the pumping pump 15 is not used for collecting water, when a predetermined amount of water is accumulated in the casing pipe, the pump is used only for the time of pumping the water. The vacuum pump 28 can save time.
Since the action of maintaining the negative pressure applied to the casing pipe and the operation time of the pump 15 are intermittently performed, it is possible to reduce energy such as electric power used and improve water collection efficiency. Becomes In order to operate the pump pump 15, the casing pipe 10
A device that automatically detects the water level is installed inside the
It is also possible to automatically detect the water level inside the pipe and perform a pumping operation to perform control such that the water level is maintained at a predetermined height.

In the above-mentioned embodiment, the well point rows 8 arranged around the excavation part 2 are not only arranged in one row, but are arranged in two rows or a plurality of rows as in the case of the conventional well points. Then, you may pump up groundwater. The length and inner diameter of the casing pipe may be of any size depending on the condition of the construction site, and the configuration of the riser pipe and the well point provided at the lower end of the casing pipe. Etc., it is possible to use an arbitrary configuration according to the state of groundwater at the construction site. Furthermore, the filter material 6 provided inside the downhole also
When collecting water at the well point, use a material that reduces the mixing of fine particles of soil, etc. A material may be used, and the thickness and the like of the filter material can be appropriately set.

[0025]

With the above-described structure, the present apparatus favorably performs the action of lowering the water level of groundwater without imposing a heavy burden on the pump even at the construction site of deep underground excavation. be able to.
And, also when constructing the pumping apparatus, it is possible to use the same construction method as the conventional well point,
Excavation at large depth and installation of equipment can be easily performed.
Also, even if the well point is installed at a deep position, the sand filter material filling the inside of the downhole will
Since only water can be separated and drained in a state where fine particles of soil are filtered, the burden on ground facilities can be reduced. further,
When using a means for constantly applying a negative pressure to the casing pipe, the load on the pump can be reduced,
Since the operating time of the pump can be shortened, the energy used can be reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of an apparatus of the present invention.

FIG. 2 is an explanatory diagram of a state of excavating a vertical hole.

FIG. 3 is an explanatory diagram of a state in which a water collecting mechanism such as a pipe is installed.

FIG. 4 is a cross-sectional view of an example of constructing a well point around a construction site.

5 is a plan view corresponding to FIG. 4. FIG.

[Explanation of symbols]

1 construction ground, 2 excavator, 3 excavator,
4 pumping equipment, 5 downhole, 6 filter material, 7 sealing material (caulking material), 8 well point row, 10 casing pipe, 11 pipe lid, 12 riser pipe, 13 well point, 15 pumping pump, 16 pumping pipe, 1
7 valves, 18 ground pipes, 20 separate tanks, 21 drainage pumps, 22 drainage pipes, 25 exhaust system, 26/27 exhaust pipes,
28 Vacuum pump.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryo Hatano             Nishi-ku, Sapporo City, Hokkaido             Chiwa Sanwa Foundation Co., Ltd. F-term (reference) 2D043 DA01 DA04

Claims (6)

[Claims] 1. A pumping apparatus constructed by arranging a large number at predetermined intervals so as to surround a construction area for deeply excavating the ground, wherein the pumping apparatus is an underground excavation hole and the inside of the excavation hole. A casing pipe to be installed in, a riser pipe provided with a plurality of well points connected to the lower portion of the casing pipe, a casing pipe in the downhole and a filter material filling the riser pipe and the periphery of the well point, A high-lift well-point device comprising: a sealing member provided on an upper portion of a casing pipe and a sealing member provided on an upper portion of a filter material. 2. The construction of the water pumping apparatus according to claim 1, wherein a layer of filter material having high water permeability is provided around the casing pipe and the riser pipe installed in the downhole. High lift well point device. 3. The mud in the hole is replaced with fresh water and sand when constructing the filter material after excavating the downhole with muddy water and installing the casing pipe and the well point inside the downhole. By making it possible, it is possible to construct a filter layer having good water permeability.
High lift well point device described in. 4. An exhaust system is connected to the casing pipe and a separate tank for temporarily storing water pumped by a pump, and a negative pressure is applied to the inside of the casing pipe by the exhaust system. The high-lift well point device according to claim 1 or 2, which is used for separating air and water in a tank. 5. The pump according to claim 1, wherein a pump is arranged inside the casing pipe, and the pump pump collects water into a separate tank through a pump pipe, separates it into steam and discharges it. High-lift well point device according to Crab. 6. A negative pressure is constantly applied to the casing pipe by a means for applying a negative pressure to cause a water collecting action through a well point, and the water is pumped by the water pump. The high-lift well point device according to claim 4 or 5.