JP4074313B2 - Structure of steel sheet pile for water flow and water retaining wall, and its construction method. - Google Patents

Description

  The present invention relates to a water-permeable steel sheet pile, a structure of a water-permeable retaining wall, and a construction method thereof.

Conventionally, methods for adding a water flow function to a water-impervious earth retaining wall such as an SMW wall include the following methods.
<1> A method of securing a water flow space by inserting a water injection tube into unsolidified soil cement, expanding the tube, and extruding the soil cement.
<2> A method of inserting a split screen with filter material into unsolidified soil cement and pressing the screen against a natural ground with an expansion jack to secure a water passage space.
<3> A method of drilling the soil cement to secure a water passage space after the soil cement wall is hardened.
<4> A special core material with a water flow device with a piston (a member with a steel cover attached to the end of a circular pipe) is built in unsolidified soil cement, and the piston is inserted into the back ground after hardening the soil cement The steel cover at the tip of the piston is melted by electrolytic corrosion to achieve the water flow function.

However, the conventional method for adding a water flow function has the following problems.
<1> It is difficult to completely remove the soil cement in the water flow section, and depending on the extrusion condition of the soil cement, it may not be possible to secure a sufficient input space for the filter material. May be a problem. Furthermore, in large-scale excavation work that requires a long time to construct the retaining wall, it is necessary to take separate measures for the purpose of maintaining the groundwater flow when constructing the retaining wall.
<2> It is difficult to completely remove the soil cement in the water passage portion, and there is a possibility that the deterioration of the water passage function becomes a problem. In addition, since the core material has a special shape, it may be difficult to install the core material depending on the depth and condition of the soil cement.
<3> Soil cement often enters the back ground of the SMW wall, and it is difficult to remove all of this with a drilling hole, so excavation of the site portion on the back of the SMW wall is required. In addition, a heavy construction machine such as an all-round rotary excavator is required for drilling the soil cement, which increases the burden in terms of construction period and construction cost. Furthermore, in large-scale excavation work that requires a long period of time for the construction of the retaining wall, it is necessary to take separate measures for the purpose of maintaining the groundwater flow during the construction of the retaining wall.
<4> The water flow capacity is low in reliability because it depends on the piston insertion situation. Moreover, since the hardened soil cement between the back ground of a piston cannot be removed, there exists a possibility that the fall of a water flow function may become a problem. Furthermore, in large-scale excavation work that requires a long period of time to construct the retaining wall, it is necessary to take separate measures for the purpose of groundwater flow conservation when constructing the retaining wall.

  In order to solve the above-mentioned problems, the invention according to claim 1 is constituted by a steel sheet pile and an inner water pipe arranged along the longitudinal direction, and the inner water pipe is a cylindrical body whose bottom is closed. The upper part is opened with an inner cylinder opening, the lower part is opened with a sheet pile opening that penetrates the steel sheet pile for water flow, and a valve is arranged between the inner cylinder opening and the sheet pile opening. It features a structure of a steel sheet pile for water passage provided with a valve seat.

  The invention according to claim 2 is constituted by a steel sheet pile, an inner water pipe arranged along the longitudinal direction, and an outer water pipe, and the inner water pipe is a cylinder whose bottom is closed, A valve seat that opens an inner cylinder opening at the upper part, opens a sheet pile opening that penetrates the water-permeable steel sheet pile at the lower part, and arranges a valve between the inner cylinder opening part and the sheet pile opening part The outer water pipe is a cylinder body that is open toward the steel sheet pile for water flow through the bottom, and is characterized by the structure of a steel sheet pile for water flow that is formed with an outer cylinder opening at the top. Is.

  Further, the invention described in claim 3 is a water passage vertical hole excavated in a part of the water retaining wall, and the water passage steel described in claim 1 or 2 inserted in the water passage vertical hole. It is characterized by the structure of a water retaining wall made up of sheet piles.

In the invention according to claim 4, a retaining wall is constructed on both sides of the range to be excavated, a water passage vertical hole is drilled in a part of the retaining wall, and the inside of the water passage vertical hole is charged. The steel sheet pile for passing water according to Item 1 is installed,
Before excavation, the upstream groundwater is introduced from the inner cylinder opening that opens into the inner water pipe of the upstream steel sheet pile, and passes through the sheet pile opening to drain into the planned cutting area. , The groundwater is introduced from the sheet pile opening of the downstream steel sheet pile for water flow, and is allowed to flow through the inner cylinder opening to the downstream side,
During excavation, in the upstream and downstream water-flowing steel sheet pile, a plug is installed on the valve seat in the inner water-flowing cylinder to close it, and the upstream groundwater is in the upstream water-flowing steel sheet pile, The groundwater sucked by the pump arranged inside the inner water pipe is made to flow into the inside of the inner water pipe in the downstream water sheet pile, and passed through the inner cylinder opening of the inner water pipe. To the downstream side,
After the excavation is completed, a buried water channel is installed in the excavation bottom or part of the underground structure provided in the excavation part, and between this buried water channel and the sheet pile opening of the water sheet piles on both sides, or the steel sheet piles for water flow Connecting the newly opened sheet pile openings, removing the valve seat plugs in the inner water pipe of the upstream and downstream water sheet piles, and opening the upstream ground water Introduced into the buried channel from the sheet pile opening of the water-flowing steel sheet pile or newly opened sheet pile, and the groundwater flows into the inside water pipe from the sheet-pile opening of the downstream water-flowing steel sheet pile And let it flow through the inner cylinder opening and let it flow downstream.
It features the construction method of the water retaining wall.

Further, in the invention described in claim 5 , a retaining wall is constructed on both sides of the range to be excavated, a water passage vertical hole is drilled in a part of the retaining wall, and the inside of the water passage vertical hole is charged. The steel sheet pile for water flow according to Item 2 is installed, and the water sheet material is filled around the water sheet pile for water flow,
Before excavation, the upstream groundwater is introduced from the inner cylinder opening that opens to the inner water pipe in the upstream steel sheet pile, and then passes through the sheet pile opening and flows out into the cut area. In the downstream steel sheet pile for water flow, the groundwater that has flowed into the excavated area is introduced from the sheet pile opening, and is allowed to flow downstream through the inner cylinder opening.
During excavation, in the upstream and downstream water-flowing steel sheet pile, a plug is installed on the valve seat in the inner water-flowing cylinder to close it, and the upstream groundwater is in the upstream water-flowing steel sheet pile, Suctioned by a pump disposed inside the outer water pipe, the groundwater flows into the outer water pipe of the downstream water sheet pile, passes through the outer cylinder opening, and flows downstream.
After excavation is complete, the upstream and downstream water-flowing steel sheet piles are closed with the plugs installed in the valve seats in the inner water-flow pipes, and buried in the excavation bottom or part of the underground structure provided at the excavation part. A water channel is installed, this buried water channel is connected to the bottom of the outer water pipe on both sides, and the upstream groundwater is introduced into the buried water channel through the outer tube opening of the outer water pipe of the upstream steel sheet pile. Then, the groundwater is caused to flow into the outer water pipe of the downstream water-flowing steel sheet pile, to pass through the outer cylinder opening and to flow out to the downstream side .

The steel sheet pile for water flow and the structure of the water flow retaining wall described in each of the above claims and the construction method thereof can obtain the following effects.
<1> Even if a retaining wall is constructed, the construction does not block the flow of groundwater, and a high water flow capacity can be secured.
<2> Water stoppage with a water stopcock can stop the water flow function reliably and easily.
<3> Since the solidification material such as soil cement is not injected around the well during the construction of the retaining wall, it is highly reliable against the decrease in water flow capacity caused by clogging.
<4> Water flow capacity can be secured in the entire construction process from the time of construction of the retaining wall to the time of internal excavation and frame construction.
<5> According to the invention described in claim 2, it is possible to apply different water pressures to the front and back grounds partitioned by the retaining wall by installing a pump in each of the inner and outer water pipes.

  Embodiments of the structure and construction method of the water-flowing steel sheet pile and water-retaining retaining wall according to the present invention will be described below with reference to the drawings. The invention according to Item 1 will be described.

<1> Configuration of the water retaining wall. (Figure 2)
It is necessary to excavate the ground to build the underground structure.
However, if the ground is excavated, the surrounding walls will collapse.
Therefore, the retaining wall 1 is a continuous wall body that is constructed underground in advance outside the range to be cut.
The retaining wall 1 has a water-impermeable function that does not allow water to pass through, and is required to prevent water from passing to the cut-off side.
This non-water-permeable retaining wall 1 is known by a structure such as a structure in which column-shaped water-stopping columns are continuously formed in the ground, a retaining wall 1 in which sheet piles and steel pipe sheet piles are continuously placed, or an SMW method. The configuration and method of the present invention can also be applied to various known methods.
The structure of the water retaining wall of the present invention is constructed by drilling the water vertical holes 2 in a part of the retaining wall 1 which is a non-water-permeable part to provide a water-permeable part.
Below, the structure of a water flow part is demonstrated by making into an example the earth retaining wall 1 comprised by what is called a columnar row method known by names, such as a SMW method.
The water flow part provided in a part of the retaining wall is constituted by inserting a water flow steel sheet pile 3 into the water flow vertical hole 2 as described below.

<2> Drilling.
Since a series of retaining walls 1 are constructed for each of a plurality of units by any of the construction methods, a water passage vertical hole 2 for forming the structure of the present invention is drilled between the units.
Therefore, the water flow vertical hole 2 is constructed as a part of the retaining wall 1 on the line of the retaining wall 1.
A known method such as reverse circulation, auger drilling, or the like can be employed for drilling the water passage vertical hole 2.

<3> Structure of the steel sheet pile for water flow. (Figure 1)
The water-permeable steel sheet pile 3 is constituted by a general steel sheet pile and two cylinders arranged on the inner side along the longitudinal direction thereof.
The steel sheet pile of this invention is equipped with the joint of a water stop structure in the both ends similarly to a general steel sheet pile.
In the following, “inside” refers to the bottom portion of the “U” shape or the direction of the bottom in a steel sheet pile having a “U” cross section, and “outside” refers to the opposite.
The two cylinders arranged on the steel sheet pile are an inner water pipe 31 on the side close to the bottom of the U-shaped steel sheet pile and an outer water pipe 32 on the side away from the bottom.

<3-1> Inside water pipe.
The inner water flow cylinder 31 is a cylinder whose bottom is closed.
The inner water pipe 31 is installed on the inner surface of the water-use steel sheet pile 3 in parallel with the longitudinal direction of the steel sheet pile, and a part or all of the inner water-pipe 31 is constituted by a rectangular parallelepiped.
The reason why part or all is formed in a rectangular parallelepiped is to facilitate attachment to the inner surface of the steel sheet pile.
An inner cylinder opening 31 a is opened at the upper part of the inner water-permeable cylinder 31.
In the lower part of the inner water pipe 31, a sheet pile opening 3 a penetrating the water steel sheet pile 3 is opened at a position where the water sheet pile 3 contacts.
A valve seat 31d is provided at a position between the inner cylinder opening 31a and the sheet pile opening 3a.
As the valve seat 31d, for example, a rubber ring is disposed inside the inner water pipe 31, and the inner diameter of the inner water pipe 31 is partially reduced.
And the structure which makes the small diameter part function as the valve seat 31d, and fits the spherical body or the truncated cone-shaped stopper 31c to the valve seat 31d is employable.

<3-2> Outside water pipe.
The outer water pipe 32 is a hollow cylinder installed on the outer side of the water sheet pile 3 for water passage in parallel with the longitudinal direction of the steel sheet pile.
An outer cylinder opening 32 a is opened at a part of the outer water flow cylinder 32.
A lower water passage 33 is positioned below the inner water pipe 31 and the outer water pipe 32.
The inner side of the lower water passage 33 is fixed to the inner surface of the water sheet pile 3 for water passage.
The upper part of the lower water passage 33 is in communication with the outer water pipe 32 and is not in communication with the inner water pipe 31.

<4> Insertion of the steel sheet pile 3 for water flow.
As described above, the steel sheet pile 3 for water passage in a state where two water pipes are held inside,
Insert into the water passage vertical hole 2.
The water passage vertical hole 2 is filled with a stable liquid having a large specific gravity such as bentonite so that the wall does not collapse during drilling.
Since such a solution gives the water blocking property to the wall surface of the water passage vertical hole 2, groundwater is collected from the upstream side of the water passage vertical hole 2 or downstream from the water passage vertical hole 2 as the object of the present invention. It may be inappropriate to discharge groundwater to the side, so it is necessary to remove it as much as possible.
When the ground is good and the possibility of collapse is low, a normal pipe is inserted into the water passage vertical hole 2 as a washing pipe, and fresh water is supplied from the bottom of the water passage vertical hole 2 so that bentonite etc. It discharges | emits from the upper part of the hole 2, and the water permeability of the wall surface of the water flow vertical hole 2 is recovered.

<5> Filling with water-permeable material.
There are gaps between the inner water flow tube 31 and the outer water flow tube 32 and the water flow vertical hole 2.
The gap is filled with a water-permeable material 25.
This water-permeable material 25 can use a normal aggregate.
By filling the water flow material 25, the groundwater can flow into the water flow vertical hole 2 or flow out of the water flow vertical hole 2.

<6> Water flow state before excavation. (Figure 3)
As described above, the retaining wall 1 is constructed on both sides of the range to be excavated.
By constructing a water passage vertical hole 2 in a part of the retaining wall 1, the water passage vertical hole 2 for maintaining water permeability and the non-water-permeable soil retaining wall 1 are integrated.
The flow of groundwater is blocked at the position of the retaining wall 1.
However, as will be described below, the flow from the upstream to the downstream can be maintained only at the position where the water passage vertical hole 2 is installed.
That is, the groundwater from the upstream passes through the water passage material 25 of the upstream water passage vertical hole 2, flows into the inner water tube 31 from the inner tube opening 31a, and is discharged downstream from the sheet pile opening 3a.
Thus, the groundwater flowing into the water passage vertical hole 2 flows through the ground in the planned excavation range and arrives at the vertical water passage hole 2 on the downstream side of the planned excavation range.
In the water flow vertical hole 2 on the downstream side, it flows into the inner water flow cylinder 31 from the sheet pile opening 3 a, is discharged from the inner cylinder opening 31 a, and flows out into the ground downstream of the water flow vertical hole 2.

<7> Under excavation work. (Fig. 4)
Before excavating the ground between the retaining walls on both sides, the groundwater on the upstream side and the downstream side is prevented from flowing into the excavation inside through the inner water pipe 31 during excavation.
For this purpose, a plug 31c is provided on the valve seat inside the inner water pipe 31 to block water flow.
Then, a pump is installed in the outer side water pipe 32 on the upstream side, and the collected ground water in the outer side water pipe 32 is pumped up by the pump 6.
Then, water is passed through the pipe 61 through the outer water flow pipe 32 of the water flow vertical hole 2 provided on the opposite side of the cut portion.
This pipe 61 crosses the groundwater beyond the cut-out portion.
The water in the downstream outer water pipe 32 that has received water flows into the downstream ground through the outer cylinder opening 32 a of the outer water pipe 32.
Thus, the groundwater flow is not interrupted during the excavation work.

<8> At the completion of excavation. (Fig. 5)
When the excavation reaches the bottom of the excavation schedule, the buried water channel 7 is provided at an optimum depth below the groundwater level in accordance with the construction of the underground structure 8, that is, considering the positional relationship between the aquifer and the underground structure 8.
The buried water channel 7 can be constructed by digging a groove in the bottom of the excavation and burying a pipe in the groove.
Both ends of the water passage 7 are connected to the lower water passage 33 through the steel sheet pile 3 for water passage. These connections can be easily made from within the excavation.
If pumping up by the pump 6 is stopped in this state, the groundwater accumulated in the outer water pipe 32 passes through the lower water passage 33 on the upstream side, passes through the buried water passage 7 and reaches the lower water passage 33 on the downstream side.
Thus, water can be passed through the ground from the upstream side to the downstream side at a place beyond the excavation place.

<9> Construction of underground structures. (Fig. 5)
When excavation is completed to the planned depth, the underground structure 8 is constructed thereafter.
In that case, since the buried water channel 7 is arranged inside the excavation, the buried water channel 7 on the lower surface of the structure 8 can be used as a ground water channel as it is.
From the groundwater level, the buried waterway 7 can be installed in parallel with the construction of the underground structure 8 by piping to the top of the structure 8 or piping inside the housing of the underground structure 8. is there.

<10> Cleaning of the water passing material 25.
It is also conceivable that the water flow capacity of the water flow material 25 decreases due to long-term use.
In that case, since the inside of the inner water pipe 31 and the outer water pipe 32 is maintained in an open state, various maintenance such as cleaning the water passage material 25 by inserting a jet nozzle from the open portion is performed. It can be carried out.

<11> In the case of only the inner water pipe. (Figs. 6-9)
In the above embodiment, the water flow steel sheet pile 3 including the inner water flow tube 31 and the outer water flow tube 32 has been described.
However, particularly when the aquifer is thick, when the groundwater level is high, or when water permeability is good, as shown in FIG. It is possible to employ a configuration that is arranged as shown in FIG.
This embodiment will be described according to the construction sequence. In the case of before excavation as shown in FIG. 3, the upstream side uses only the inner water pipe 31 to pass water into the ground before excavation, and on the downstream side. Water can be passed from the ground.
During excavation, as shown in FIG. 7, the plug 31c is inserted into a valve seat 31d provided in the middle of the inner water pipe 31, thereby blocking the water flow between the inner cylinder opening 31a and the sheet pile opening 3a.
In this state, the pump 6 is inserted from above the inner water pipe 31 to draw up water inside the inner water pipe 31.
Then, water is injected into the downstream inner water pipe 31 through a cross pipe 61 that crosses the excavation part.
After excavation, as shown in FIG. 8, the buried water channel 7 is provided before and after the construction of the underground structure 8. This water channel 7 is a pipe arranged at a position above the sheet pile opening 3a and to a position below the stop cock 31c. For example, a square pipe is a lower half of the underground structure 8 as shown in FIG. It is arranged in a U shape along the periphery of.
After completion of the underground structure 8, the pump 6 is removed from the inside of the inner water pipe 31, and the stopper 31c with a rope, for example, is pulled up.
Then, the upstream groundwater flows from the inner cylinder opening 31 a through the inner water pipe 31, the sheet pile opening 3 a, and the buried water channel 7 into the downstream inner water pipe 31.
In addition, an opening part can be newly opened to a sheet pile, and it can also be used by connecting between this new sheet pile opening part by the buried water channel 7. FIG.

<12> A plurality of outer water pipes.
In the embodiment shown in the figure, when the outer water pipe 32 is provided, only one embodiment is shown.
However, the number of outer water pipes 32 is not limited to one, and a plurality of outer water pipes 32 may be provided. Incorporation of groundwater may be facilitated by using a plurality of outer water pipes 32.

Explanatory drawing of the Example of the steel sheet pile for water flow which comprises the water flow retaining wall of this invention. Explanatory drawing of the state which has arrange | positioned the steel sheet pile for water flow through a part of earth retaining wall. Explanatory drawing of the water flow state of groundwater before excavation. Explanatory drawing of the water supply state of groundwater under excavation. Explanatory drawing of the water flow state of groundwater when excavation is completed. Explanatory drawing of the steel sheet pile for water flow which does not provide an outer water flow cylinder. Explanatory drawing of the construction order by the steel sheet pile for water flow which does not provide an outer water flow cylinder. Explanatory drawing of the construction order by the steel sheet pile for water flow which does not provide an outer water flow cylinder. Explanatory drawing of the arrangement | positioning state of the steel sheet pile for water flow which does not provide an outer water flow cylinder.

Explanation of symbols

1: retaining wall
2: Vertical water passage
3: Steel sheet pile for water flow
31: Inside water pipe
31a: Inner cylinder opening
31c: stopper
32: Outside water pipe
32a: outer cylinder opening
33: Lower waterway
6: Pump
61: Pipe
7: buried channel
8: Underground structure

Claims (5)

Steel sheet piles,
It is constituted by an inner water pipe arranged along the longitudinal direction,
The inner water pipe is a cylinder whose bottom is closed,
Open the inner cylinder opening at the top,
In the lower part, open the sheet pile opening that penetrates the steel sheet pile for water flow,
A valve seat is provided between the inner cylinder opening and the sheet pile opening to place the valve.
Structure of steel sheet pile for water flow. Steel sheet piles,
It is constituted by an inner water pipe arranged along the longitudinal direction and an outer water pipe,
The inner water pipe is a cylinder whose bottom is closed,
Open the inner cylinder opening at the top,
In the lower part, open the sheet pile opening that penetrates the steel sheet pile for water flow,
A valve seat is provided between the inner cylinder opening and the sheet pile opening to place the valve.
The outer water pipe is a cylinder body that opens toward the steel sheet pile for water flow through the bottom,
In the upper part, an outer cylinder opening is opened,
Structure of steel sheet pile for water flow. A water passage vertical hole excavated in a part of the water retaining wall,
The water flow steel sheet pile according to claim 1 or 2 inserted in the water flow vertical hole and a water flow material disposed around the water flow steel sheet pile,
Structure of water retaining wall. Build retaining walls on both sides of the planned excavation area,
A part of the retaining wall is drilled with a water passage vertical hole,
The steel sheet pile for water flow according to claim 1 is installed inside the water flow vertical hole,
Fill the periphery of the steel sheet pile for water flow with a water flow material,
Before excavation,
Upstream groundwater,
Introducing from the inner cylinder opening that opened to the inner water pipe of the upstream steel sheet pile for water flow, let the sheet pile opening pass, and let it flow into the planned cutting area,
Introducing the groundwater from the sheet pile opening of the downstream steel sheet pile for water flow, passing through the inner cylinder opening and letting it flow downstream,
During excavation,
In the steel sheet pile for water flow on the upstream side and downstream side, a plug is installed on the valve seat in the inner water pipe to close it,
Upstream groundwater,
Suction by a pump arranged inside the inner water pipe of the steel sheet pile for water flow on the upstream side,
The groundwater is allowed to flow into the inner water pipe of the downstream steel sheet pile,
Let it pass through the inner cylinder opening and let it flow downstream,
After excavation is complete,
A buried waterway was installed in a part of the underground structure to be installed in the excavation bottom or excavated part, and a new opening was made between this buried waterway and the sheet pile opening of the water sheet piles on both sides, or in the water sheet piles for water flow. Connecting between sheet pile openings,
Open and remove the valve seat plug in the inner water pipe of the upstream and downstream water sheet piles,
The upstream groundwater is introduced into the buried channel from the sheet pile opening of the upstream water sheet pile, or from the newly opened sheet pile opening,
The groundwater is allowed to flow into the inside water pipe from the sheet pile opening of the downstream water sheet pile,
Perform by passing the inner cylinder opening and letting it flow downstream.
Construction method of water retaining wall. Build retaining walls on both sides of the planned excavation area,
A part of the retaining wall is drilled with a water passage vertical hole,
The steel sheet pile for water flow according to claim 2 is installed inside the water flow vertical hole,
Fill the periphery of the steel sheet pile for water flow with a water flow material,
Before excavation,
Upstream groundwater,
Introducing from the inner cylinder opening that opened to the inner water pipe of the upstream water sheet pile , let the sheet pile opening pass through, and let it flow into the excavation area.
Introducing the groundwater from the sheet pile opening of the downstream steel sheet pile for water flow, passing through the inner cylinder opening and letting it flow downstream,
During excavation,
Install a stopper on the valve seat in the inner water pipe of the steel sheet pile for water flow on the upstream side and downstream side to close it,
Upstream groundwater,
Suction by a pump placed inside the outer water pipe of the steel sheet pile for water flow on the upstream side,
Let the groundwater flow into the inside of the outer water pipe of the downstream steel sheet pile,
Let it pass through the outer cylinder opening of the outer water pipe and let it flow downstream,
After excavation is complete,
The upstream side and the downstream side of the water sheet pile for water flow are closed with the stoppers installed in the valve seats inside the water flow pipes,
A buried water channel is installed in the excavation bottom or a part of the underground structure provided in the excavation part, and this buried water channel is connected to the bottoms of the outer water pipes on both sides.
Upstream groundwater,
Introducing into the buried channel through the outer cylinder opening of the outer water pipe of the steel sheet pile for water flow on the upstream side,
The groundwater is allowed to flow inside the outer water pipe of the downstream steel sheet pile,
This is done by passing the outer cylinder opening and letting it flow downstream.
Construction method of water retaining wall.

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