Weep hole and earth retaining structure and underground structure provided with same

Abstract

To provide a weep hole that suppresses a decrease in operating efficiency of an apparatus for decompressing or pressurizing the interior of a hollow tube by blocking air flow through the weep hole, while being capable of suppressing a decrease in water flow rate.SOLUTION: A weep hole 20 according to the present invention comprises: a main check valve 23 that allows only water flow from a water intake 21 to a water discharge port 22 and prohibits water flow in a reverse direction; and s float valve 24 of a float valve type that opens a flow path by buoyancy during water flow on the upstream side and closes the flow path so as not to cause air flow from the water intake 21 toward the water discharge port 22 when the main check valve 23 is closed. In order to allow water flow from an interior space 5 of the underground structure 1 to the ground, the water inflow hole 13 is formed in a tube wall portion on the interior space 5 side of the hollow tube 11, and a water outflow hole 14 is formed in the tube wall portion on the ground side of the hollow tube 11, and the weep hole 20 is provided in each of the inflow hole 13 and the outflow hole 14.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present invention relates to a weep hole equipped with a backflow prevention function that allows water to flow only in a certain direction and prohibits water from flowing in the opposite direction, and to an earth retaining structure and an underground structure equipped with the same. [Background technology]

[0002] With recent urbanization and housing development, the problem of rainwater not being able to fully infiltrate underground and running off has been increasing. As part of the countermeasures, large-capacity underground structures are being constructed to temporarily store rainwater underground, and the rainwater stored in these structures is being recharged into the ground (returned as groundwater).

[0003] Traditionally, such large-capacity underground structures have typically had the upper and lower decks and side walls constructed using cast-in-place concrete, but the cast-in-place concrete method has led to problems such as additional labor required and longer construction times.

[0004] For this reason, in recent years, construction methods that use precast concrete or PC walls to construct the structure have become more common in order to reduce construction labor.

[0005] The present applicant has also proposed an underground structure for saving labor in the construction method, reducing construction costs, and for effectively utilizing the storage space in the following Patent Documents 1 and 2. Specifically, as shown in Fig. 18 and Fig. 19, a rainwater storage space 54 is formed by a side wall 51 formed by horizontally placing hollow circular pipes 50 adjacent to each other in the ground, an upper floor slab 52, and a lower floor slab 53, and a rainwater inflow hole 55 for causing rainwater to flow into the pipe is formed by providing a weep hole 56 that allows only the rainwater to flow into the pipe in the pipe wall portion corresponding to the rainwater storage space 54, and a ground inflow hole 57 for causing rainwater to flow into the ground is formed by providing a weep hole 58 that allows only the rainwater to flow out to the ground in the pipe wall portion corresponding to the ground, and an underground structure 60 with a ground infiltration function has been proposed, which is a hollow circular pipe for ground infiltration 59. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2009-235876 A [Patent Document 2] JP 2016-132957 A Summary of the Invention [Problem to be solved by the invention]

[0007] In addition, in the above-mentioned Patent Document 2, when the inflow of rainwater from the ground stops and the water level in the rainwater storage space 54 becomes lower than the groundwater level in the ground, drainage from the ground infiltration hole 57 stops and groundwater is not recharged. As shown in FIG. 20, a vacuum pump 61 is provided to make the inside of the hollow circular pipe 50 negative pressure, so that the rainwater stored in the rainwater storage space 54 flows into the pipe through the rainwater inlet hole 55. By operating this vacuum pump 61 to make the inside of the hollow circular pipe 50 negative pressure, the rainwater in the rainwater storage space 54 can be forced to flow from the rainwater inlet hole 55 through the weep hole 56 into the pipe. Similarly, by providing a blower 62 to pressurize the inside of the hollow circular pipe 50, the rainwater in the hollow circular pipe 50 can be forced to flow from the ground infiltration hole 57 through the weep hole 58 into the ground.

[0008] However, when negative pressure is created inside the hollow circular pipe 50 and the rainwater in the rainwater storage space 54 is forced to flow from the rainwater inlet 55 through the weep hole 56 into the hollow circular pipe 50, the water level in the rainwater storage space 54 drops, as shown in Figure 21(A), and the weep hole 56 provided in the rainwater inlet 55 is positioned above this water level, so that rainwater does not flow in and air is taken in.

[0009] Similarly, when pressurizing the hollow circular pipe 50 and forcing the rainwater in the hollow circular pipe 50 through the ground infiltration hole 57 and through the weep hole 58 to flow out into the ground, as shown in Figure 21 (B), the water level in the hollow circular pipe 50 drops, and when the weep hole 58 in the ground infiltration hole 57 is positioned above this water level, the rainwater does not flow out and air is discharged.

[0010] When air flows in and out through the weep holes 56 and 58 as described above, the efficiency of the vacuum pump 61 (blower 62) which reduces (pressurizes) the pressure inside the hollow circular pipe 50 decreases, and the amount of water passing through also decreases, resulting in a problem of a decrease in the groundwater recharge function.

[0011] Therefore, the main object of the present invention is to provide a weep hole that prevents a decrease in the operating efficiency of equipment that reduces or increases pressure inside a hollow pipe by blocking the flow of air through the weep hole, while also suppressing a decrease in water flow, as well as a retaining structure and underground structure equipped with the same. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention as claimed in claim 1 provides a weep hole which is characterized by having a main check valve that allows water to flow only from the intake to the discharge outlet and prohibits water from flowing in the opposite direction, and also having a float valve upstream of the main check valve that opens the flow path by buoyancy while water is passing through, and closes the flow path when the main check valve is closed so that air does not flow from the intake to the discharge outlet.

[0013] In the invention described in claim 1, a main check valve is provided that allows water to flow only from the intake port to the discharge port and prohibits water from flowing in the opposite direction, and a float valve of a float type is provided upstream of the main check valve that closes the flow path so that air does not flow from the intake port to the discharge port except when water is passing through. The float valve opens the flow path by buoyancy while water is passing through, allowing water to pass through, but when the main check valve is closed, it closes the flow path by sitting on the valve seat, preventing air from flowing from the intake port to the discharge port.

[0014] Therefore, even when the main check valve is closed and negative pressure is created on the outlet side by a vacuum pump to forcibly draw water into the outlet side, or when pressurization is created on the intake side by a pressure pump to forcibly push water out from the intake side, the float valve blocks the flow of air through the weep hole that is above the water level, so the operating efficiency of the vacuum pump or pressure pump installed on the outlet side or intake side can be maintained and the water flow rate through the weep hole installed below the water level can be secured.

[0015] According to a second aspect of the present invention, there is provided a weep hole as described in the first aspect, in which a filter is provided at either or both of the intake and discharge ports.

[0016] In the invention described in claim 2 above, a filter is provided at either or both of the water intake and discharge ports to prevent garbage and impurities in the water from being flushed away.

[0017] According to a third aspect of the present invention, there is provided a weep hole as defined in the first aspect, wherein the main check valve is a swing-type check valve that swings toward the water outlet side.

[0018] In the invention described in claim 3, a swing-type check valve that swings toward the water outlet side is used as the main check valve.

[0019] As a fourth aspect of the present invention, there is provided an earth retaining structure in which hollow pipes are installed horizontally adjacent to each other in the ground, A solidification material is filled in the gaps between the horizontally adjacent hollow tubes to prevent water leakage. Water passage holes are formed in a pipe wall portion of the hollow pipe in any one of a pattern in which only a water inlet hole is formed, a pattern in which only a water outlet hole is formed, and a pattern in which both a water inlet hole and a water outlet hole are formed; There is provided an earth retaining structure, characterized in that each of the water passage holes is provided with a weep hole as defined in any one of claims 1 to 3 above.

[0020] In the invention described in claim 4, in a retaining structure constructed by installing hollow pipes adjacent to each other horizontally in the ground, the weep holes are provided at the water inlet and outlet holes provided in each pattern in the pipe wall of the hollow pipes, thereby enabling water to flow through the retaining structure while blocking the flow of air through the weep holes.

[0021] The present invention according to claim 5 provides the retaining structure according to claim 4, further comprising either or both of a vacuum pump that creates a negative pressure inside the hollow pipe and a pressure pump that pressurizes the hollow pipe.

[0022] In the invention described in claim 5 above, a vacuum pump or a pressure pump is provided to create negative or positive pressure inside the hollow pipe, thereby enabling smooth water flow in the retaining structure.

[0023] According to a sixth aspect of the present invention, there is provided an underground structure in which a side wall is constructed by installing an earth retaining structure having hollow pipes horizontally adjacent to each other in the ground in a closed shape in a plan view, and a planar underground space is formed by constructing at least the lower floor slab within an area surrounded by the side wall, A solidification material is filled in the gaps between the horizontally adjacent hollow tubes to prevent water leakage. Water passage holes are formed in a pipe wall portion of the hollow pipe in any one of a pattern in which only a water inlet hole is formed, a pattern in which only a water outlet hole is formed, and a pattern in which both a water inlet hole and a water outlet hole are formed; There is provided an underground structure, characterized in that each of the water passage holes is provided with a weep hole as defined in any one of claims 1 to 3 above.

[0024] In the invention described in claim 6, in an underground structure in which an underground space is formed by constructing a subfloor slab inside an interior surrounded by side walls made of earth retaining structures with hollow pipes installed horizontally adjacent to each other in the ground, the weep holes are provided at the water inlet and outlet holes provided in the pipe wall of the hollow pipes, respectively, thereby enabling water to flow from the internal space of the underground structure to the ground while blocking the flow of air through the weep holes.

[0025] The present invention according to claim 7 provides an underground structure as described in claim 6, further comprising either or both of a vacuum pump for creating negative pressure inside the hollow pipe and a pressure pump for pressurizing the hollow pipe.

[0026] In the invention described in claim 7 above, by providing a vacuum pump or a pressure pump, negative or pressurized pressure is created inside the hollow pipe, enabling smooth flow of water from the internal space of the underground structure to the ground.

[0027] According to an eighth aspect of the present invention, there is provided an underground structure as described in claim 6, further comprising an upper deck above the side wall, which seals off the interior surrounded by the side wall.

[0028] In the invention described in claim 8 above, by providing an upper deck above the side walls to seal off the interior surrounded by the side walls, in the case of a planar underground space in which a lower deck and an upper deck are constructed within an interior surrounded by side walls installed in a closed shape when viewed in a plane, the above-ground portion of the underground structure can be effectively used as a park, parking lot, road, etc. Effect of the Invention

[0029] As described above in detail, according to the present invention, by blocking the flow of air through the weep hole, it is possible to prevent a decrease in the operating efficiency of the equipment that reduces or increases pressure, and to suppress a decrease in the amount of water flowing through the weep hole. [Brief description of the drawings]

[0030] [Figure 1]1 is a vertical cross-sectional view of an underground structure 1 according to the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a vertical cross-sectional view showing a rainwater inlet hollow pipe 7. [Figure 4] 2 is a vertical cross-sectional view of the retaining structure 2 that constitutes the side wall 3. FIG. [Diagram 5] 5 is a view (horizontal cross-sectional view) taken along line VV in FIG. 4. [Figure 6] 1A shows a weep hole 20 according to the present invention, in which (A) is a vertical cross-sectional view, (B) is a view taken along line BB in (A), and (C) is a view taken along line CC in (A). [Figure 7] 1 shows the main check valve 23, in which (A) is a diagram showing a shutoff state and (B) is a diagram showing a water-passing state. [Figure 8] 13 shows a packing 29, in which (A) is a front view and (B) is a view taken along line BB in (A). [Figure 9] 1 shows a float valve 24, in which (A) is a diagram showing a shutoff state and (B) is a diagram showing a water-passing state. [Figure 10] 1A is a diagram showing a water-passing state of a weep hole 20 provided in an inlet 13, and FIG. 1B is a diagram showing a water-blocking state of the weep hole 20. FIG. [Figure 11] 1A is a diagram showing a water-passing state of a weep hole 20 provided in an outflow hole 14, and FIG. 1B is a diagram showing a water-blocking state of the weep hole 20. FIG. [Figure 12] FIG. 4 is a cross-sectional view showing an application example (second embodiment example) of the earth retaining structure. [Figure 13] FIG. 11 is a cross-sectional view showing an application example (third embodiment example) of the earth retaining structure. [Figure 14] FIG. 11 is a cross-sectional view showing an application example (fourth embodiment) of the earth retaining structure. [Figure 15] FIG. 11 is a cross-sectional view showing an application example (fifth embodiment) of the earth retaining structure. [Figure 16] FIG. 13 is an enlarged view of a main part showing another embodiment. [Figure 17] FIG. 4 is an enlarged view showing a float valve 24 according to another embodiment. [Figure 18] FIG. 1 is a vertical cross-sectional view of an underground structure 60 according to a conventional example. [Figure 19]FIG. [Figure 20] 2 is a vertical cross-sectional view showing the water flow state of an underground structure 60. FIG. [Figure 21] 1A is a vertical cross-sectional view showing the water flow state of an underground structure 60 when negative pressure is applied inside the hollow pipe, and FIG. 1B is a vertical cross-sectional view showing the water flow state of an underground structure 60 when pressurized inside the hollow pipe. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0032] [First embodiment] The underground structure 1 of the present invention shown in Figure 1 is constructed by installing retaining structures 2 in a closed shape when viewed in a plane, constructing side walls 3, and constructing a lower deck 4 inside the area surrounded by the side walls 3 to form a planar underground space 5 (hereinafter referred to as storage space 5) for storing rainwater. An upper deck 6 is provided above the side walls 3 to seal off the area surrounded by the side walls 3, and hollow pumping pipes 7, 7... are arranged inside the area surrounded by the side walls 3 to pump up the rainwater in the storage space 5 and provide it for water use.

[0033] 3, the pumping hollow pipe 7 has a number of rainwater inlet holes 9, 9... formed in the lower pipe wall portion of the hollow pipe 7 for allowing the rainwater in the storage space 5 to flow into the hollow pipe 7, and each rainwater inlet hole 9 has a weep hole 20, which will be described in detail later, arranged with its intake port 21 facing outward and its discharge port 22 facing inward. Also, a vacuum pump 10 is provided for drawing the rainwater in the storage space 5 into the hollow pipe 7 so that the rainwater that has flowed into the hollow pipe 7 can be used for irrigation water, agricultural water, industrial water, etc.

[0034] As shown in Figures 4 and 5, the retaining structure 2 is an earth retaining structure constructed by installing hollow pipes 11, 11... horizontally adjacent to each other in the ground, in which solidification material 12 is filled in the gaps between the horizontally adjacent hollow pipes 11, 11 to prevent water leakage, water passage holes are formed in the pipe wall of the hollow pipe 11 in a pattern forming water inlet ports 13, 13... and outlet holes 14, 14..., and a permeable layer 15 is formed along the depth direction of the ground on the outer surface side (ground side) of the hollow pipe 11 in which the outlet holes 14 are formed.

[0035] The hollow pipes 11 constituting the retaining structure 2 are cast into the ground with at least a predetermined embedded length secured, thereby serving as a temporary retaining wall when excavating the interior surrounded by the side walls 3, and also constituting the main structure of the side walls 3 after completion. Therefore, there is no need to build a separate temporary retaining wall, which makes it possible to reduce the labor required for construction and shorten the construction period.

[0036] As the hollow pipe 11, a high-strength concrete pile or a PC hollow pile in which prestressing is introduced or a steel pipe is arranged around the periphery can be used. The hollow pipe 11 constituting the side wall 3 is installed by a pre-boring method in which a pile is inserted into a part in which the ground has been excavated or loosened in advance. The permeable layer 15 is formed by forming a pre-boring hole 16 for installing the hollow pipe 11 larger than the outer diameter of the hollow pipe 11, and filling the space between the outer surface of the hollow pipe 11 and the pre-boring hole 16 with crushed stone. As shown in the figure, the hollow pipe 11 is arranged in a biased arrangement in a plan view with respect to the pre-boring hole 16, that is, by arranging it biased toward the storage space 5 side, the permeable layer 15 is made into a crescent-shaped permeable layer 15, and the thickness D of the permeable layer 15 is ensured. The thickness D of the permeable layer 15 is preferably about 100 to 300 mm, and preferably about 150 to 250 mm.

[0037] As shown in Fig. 5, a metal fitting 17 is provided on the outer surface of the hollow tube at a position close to the adjacent hollow tube 11 so as to have a pair of protruding strips 17a, 17b protruding outward along the longitudinal direction of the member to define a filling area of ​​the solidification material 12. The metal fitting 17 can be attached by embedding a screw-shaped insert metal fitting (not shown) in advance when the hollow tube 11 is manufactured, and then fixing two angle members with bolts to the insert metal fitting or attaching an unequal groove steel to provide the pair of protruding strips 17a, 17b protruding outward. A filling area of ​​the solidification material 12 blocked by the protruding strips 17a, 17b is defined in the gap between the adjacent hollow tubes 11, 11. In other words, the tips of the protrusions 17a, 17b are long enough to reach the pre-boring hole 16, thereby defining a filling area for the solidification material 12, and by filling this filling area with a cement-based solidification material such as mortar or concrete, the function of the solidification material as a water-stopping wall that continues in the direction of the pile row is ensured.

[0038] The hollow pipe 11 that constitutes the retaining structure 2 has a plurality of water inlet holes 13, 13... formed at a predetermined interval in the pipe axial direction in the pipe wall portion on the storage space 5 side, and a plurality of water outlet holes 14, 14... formed at a predetermined interval in the pipe axial direction in the pipe wall portion on the ground side, with the boundary being the area defined by the protrusion pieces 17a, 17b and partitioned off by filling the solidification material 12.

[0039] The inlet holes 13, 13... and the outlet holes 14, 14... are each provided with a weep hole 20 (Figure 6) that allows water to flow only in a certain direction from the intake port to the discharge port and prohibits water from flowing in the opposite direction.

[0040] In the underground structure 1 configured as above, the rainwater stored in the storage space 5 flows into the hollow pipe 11 through the weep hole 20 provided in the inlet 13 of the hollow pipe 11 constituting the retaining structure 2. The rainwater that flows into the hollow pipe 11 then passes through the weep hole 20 provided in the outlet 14 to be discharged into the ground. In this underground structure 1, the permeable layer 15 is formed on the outer surface side of the hollow pipe 11 along the ground depth direction, so that even if a viscous layer N (impermeable layer) exists in the ground, the permeable layer 15 can be used as a waterway to allow water to flow, and the rainwater is discharged from all the outlet holes 14, 14... below the water level of the storage space 5, and seeps into the ground from the sand layer S (permeable layer), so that the recharge function can be significantly improved.

[0041] Incidentally, when rainwater stops flowing into the storage space 5 and the water level in the storage space 5 falls below the water level in the hollow pipe 11, the water stops flowing into the hollow pipe 11 from the inlet hole 13, and groundwater no longer recharges. Also, when the water level in the hollow pipe 11 falls below the groundwater level in the ground, discharge from the outlet hole 14 stops, and groundwater no longer recharges. As a countermeasure for such a case, the underground structure 1 (retaining structure 2) is provided with a vacuum pump 40 that creates a negative pressure inside the hollow pipe 11 and / or a pressure pump 41 that pressurizes the inside of the hollow pipe 11, as shown in FIG. 1.

[0042] When the water level in the storage space 5 is higher than the water level in the hollow tube 11, water naturally flows from the storage space 5 into the hollow tube 11 due to the hydraulic head difference, but even when the water level in the storage space 5 is equal to or lower than the water level in the hollow tube 11, the vacuum pump 40 is operated to create a negative pressure in the hollow tube 11, so that the water in the storage space 5 can be forced to flow from the inlet hole 13 through the weep hole 20 into the hollow tube 11. When the water level in the hollow tube 11 is higher than the groundwater level in the ground, water naturally flows from the hollow tube 11 into the ground due to the hydraulic head difference, but even when the water level in the hollow tube 11 is equal to or lower than the groundwater level in the ground, the pressurizing pump 41 is operated to pressurize the hollow tube 11, so that the rainwater in the hollow tube 11 can be forced to be discharged from the outlet hole 14 through the weep hole 20 to the outside of the tube.

[0043] The vacuum pump 40 and the pressure booster pump 41 for reducing or increasing the pressure inside the hollow pipe 11, as well as the vacuum pump 10 for reducing the pressure inside the pumping hollow pipe 7, are installed in a pump control room 45 provided underground or above ground, as shown in FIG. 1.

[0044] (Weep Hole 20) The weep hole 20 will be described in detail below. As shown in Fig. 6, the weep hole 20 according to the present invention is provided with a main check valve 23 that allows water to flow only from the intake 21 toward the discharge port 22 and prohibits water from flowing in the opposite direction, and is provided with a float valve 24 of a float valve type upstream of the main check valve 23 (i.e., on the intake 21 side) that opens the flow path by buoyancy while water is passing through and closes the flow path to prevent air from flowing from the intake 21 toward the discharge port 22 when the main check valve 23 is closed.

[0045] 6, the weep hole 20 comprises a cylindrical casing 26 whose open ends respectively serve as the intake 21 and the discharge 22, and a water flow passage is formed within the pipe. A partition plate 27 having a plurality of openings 27a, 27a... through which water flows is provided in the middle of the water flow passage, near the discharge 22 side, and a float valve case 28 housing the float valve 24, near the intake 21 side.

[0046] The main check valve 23 is fixed to the surface of the partition plate 27, which is provided near the outlet 22, on the side of the outlet 22, via a packing 29. The main check valve 23 is fixed to the partition plate 28 by screwing the upper part of the check valve 23 with a fixing screw 31 which penetrates the main check valve 23 and the packing 29 integrally via a seat plate 30, as shown in Fig. 6(B). In the example shown in Fig. 6(A), the lower side of the partition plate 27 is slightly inclined toward the outlet 22 to enhance the water stopping effect of the main check valve 23, but the partition plate 27 may be arranged so as to be perpendicular to the flow path.

[0047] 6(B) and 7, the main check valve 23 is a swing-type (open / close type) check valve whose upper end is fixed to the partition plate 27 and whose portion below this fixed portion swings toward the water outlet 22. The main check valve 23 is made of a water-impermeable member made of rubber, plastic, or the like formed into a circular shape so as to block the flow path inside the pipe of the casing 26, and has a linear easily bending portion 33 that runs horizontally and across the width below the portion fixed by the fixing screw 31.

[0048] When the water pressure on the intake 21 side is high, as shown in Fig. 7(B), the water pressure causes the main check valve 23 to bend from the easily bending portion 33 to the outlet 22 side, and water flows from the intake 21 side to the outlet 22 side over the main check valve 23. On the other hand, when the water pressure on the outlet 22 side is high, as shown in Fig. 7(A), the water pressure presses the main check valve 23 against the packing 29, preventing water from flowing back from the main check valve 23 to the intake 21 side.

[0049] The main check valve 23 may be a float valve of a floating type.

[0050] 8, the packing 29 is a sealing member made of rubber or the like, and serves to ensure watertightness between at least the outer periphery of the surface of the main check valve 23 facing the partition plate 27 and the partition plate 27. The packing 29 is formed with an opening 29a at its lower part, which is integral with an area corresponding to the opening groups 27a, 27a... formed in the partition plate 27, and with an opening 29b at its upper part, through which the fixing screw 31 is inserted.

[0051] As shown in Fig. 6(A) and Fig. 9, the float valve case 28 has a partitioned area that partitions the inside of the pipe of the casing 26 by a certain length in the flow direction, and the partitioned area is partitioned into two stages in the vertical direction by upper and lower partition plates 28a, and an upper and lower communication port 28b that is a vertical water passage is formed in the center of the upper and lower partition plates 28a, and an upper stage opening 28c that flows water from the water intake port 21 side into the float valve case 28 is formed on the side of the upper stage on the water intake port 21 side where the float valve 24 is provided, and a lower stage opening 28d that flows water from the float valve case 28 is formed on the side of the lower stage on the water discharge port 22 side. As a result, in the float valve case 28, water flows in the order of the upper stage opening 28c → the upper and lower communication port 28b → the lower stage opening 28d. Water that flows into the casing 26 from the water intake 21 passes through the float valve case 28 and flows out to the water discharge port 22 side.

[0052] The float valve 24 is disposed in the upper part of the float valve case 28, and when there is no water in the float valve case 28, it sits by gravity on the valve seat 25 disposed around the entire periphery of the vertical communication port 28b of the vertical partition plate 28a, closing the vertical communication port 28b, as shown in Fig. 9(A). When the float valve case 28 is filled with water, the float valve 24 floats up from the valve seat 25 due to buoyancy, as shown in Fig. 9(B), and the vertical communication port 28b is opened, allowing water to pass through.

[0053] The float valve 24 is a float made of a resin foam or a hollow resin shell that floats on water. The three-dimensional shape is a substantially inverted cone in the illustrated example, but it may be a substantially inverted truncated cone, a substantially disc, a substantially semi-disc, a substantially spherical, or a substantially semi-spherical shape. If the three-dimensional shape is other than a sphere, a valve weight 24a that protrudes downward is provided at the center of the lower end to adjust the inclination of the float valve 24 when seated.

[0054] The valve seat 25 is a member made of a ring-shaped rubber or the like, with a groove formed on its outer peripheral surface that can fit around the periphery of the upper and lower communicating port 28b, and is particularly effective in preventing air leakage when the float valve 24 is seated.

[0055] The upper stage opening 28c provided on the water intake 21 side of the float valve case 28 may be composed of a plurality of openings as shown in Fig. 6(C), or may be composed of one opening or one or a plurality of slits. There is no particular restriction on the position at which the upper stage opening 28c is provided, but in order to prevent the float valve 24 from sinking due to the water flow that flows in through the upper stage opening 28c and seating on the valve seat 25 to stop the water flow, it is preferable to provide the upper stage opening 28c at a position equal to or lower than the float valve 24 that has risen up due to buoyancy, more preferably at a lower position. This prevents the float valve 24 from seating on the valve seat 25 to stop the water flow, due to the buoyancy of the float valve 24 itself and the effect of the water flow that passes through the upper stage opening 28c pushing up the float valve 24.

[0056] In order to prevent underwater garbage, impurities, soil, and the like from flowing downstream through the weep hole 20, a filter 35 is provided in either or both of the intake port 21 and the discharge port 22, as shown in Fig. 6(A). A widely used commercially available filter can be used as the filter 35, and as in the illustrated example, a combination of a coarse filter and a fine filter can also be used. In the illustrated example, the filter 35 is provided in both the intake port 21 and the discharge port 22, but it is also possible to provide the filter 35 in only one of them and not in the other.

[0057] (Weephole 20 operation status) Next, the operation of the weep hole 20 will be described with reference to FIGS.

[0058] In an underground structure 1 equipped with an earth retaining structure 2 according to the present invention, as shown in Fig. 5, water stored in a storage space 5 flows into hollow pipe 11 through a weep hole 20 provided in a water inlet 13 formed in the pipe wall portion of hollow pipe 11 on the storage space 5 side, and then passes through a weep hole 20 provided in a water outlet 14 formed in the pipe wall portion of hollow pipe 11 on the ground side to be discharged to the ground side and recharged in the ground. Fig. 10 shows the operation of the weep hole 20 provided in the water inlet 13, and Fig. 11 shows the operation of the weep hole 20 provided in the water outlet 14.

[0059] Therefore, the weep hole 20 provided in the water inlet 13 is arranged so that the water intake 21 faces the storage space 5 and the water outlet 22 faces the inside of the hollow pipe 11. Also, the weep hole 20 provided in the water outlet 14 is arranged so that the water intake 21 faces the inside of the hollow pipe 11 and the water outlet 22 faces the ground.

[0060] First, the operation state of the weep hole 20 provided in the water inlet 13 will be described with reference to Fig. 10. As shown in Fig. 10(A), in the inlet 13 located at a position lower than the water level of the storage space 5, the water intake 21 side of the weep hole 20 provided in this inlet 13 is filled with water in the storage space 5, so that the water on the water intake 21 side passes through the upper opening 28c and flows into the float valve case 28, passes through the upper and lower communication openings 28b of the upper and lower partition plates 28a that have been opened when the float valve 24 is floated up by buoyancy, flows out from the lower opening 28d, passes through the float valve case 28, passes through the main check valve 23 that is pushed open by water pressure, and flows into the hollow pipe 11 from the discharge port 22.

[0061] Thereafter, the water level in the storage space 5 drops, and in the inlet 13 located higher than the water level in the storage space 5, as shown in FIG. 10(B), since there is no water on the intake 21 side of the weep hole 20 provided in the inlet 13, the float valve 24, which is no longer acting on buoyancy, seats on the valve seat 25 by gravity and closes the flow path. In addition, since the water pressure from the intake 21 side does not act on the main check valve 23, the main check valve 23 closes the flow path. This blocks the flow of water through the weep hole 20. Furthermore, even if the vacuum pump 40 is operated to create a negative pressure in the hollow tube 11, the float valve 24 seats on the valve seat 25 and closes the flow path, so that the air in the storage space 5 is prevented from flowing into the hollow tube 11 through the weep hole 20, and the operating efficiency of the vacuum pump 40 can be prevented from decreasing.

[0062] In addition, at the inlet 13 located below the water level in the storage space 5, water flows into the hollow tube 11 through the weep hole 20 as described above.

[0063] Next, the operation state of the weep hole 20 provided in the water outflow hole 14 will be described with reference to Fig. 11. As shown in Fig. 11(A), in the outflow hole 14 located at a position lower than the water level in the hollow pipe 11, the intake 21 side of the weep hole 20 provided in this outflow hole 14 is filled with water in the hollow pipe 11, so that the water on the intake 21 side passes through the upper opening 28c and flows into the float valve case 28, passes through the upper and lower communication openings 28b of the upper and lower partition plates 28a that have been opened as the float valve 24 floats up due to buoyancy, flows out from the lower opening 28d, passes through the float valve case 28, passes through the main check valve 23 that has been pushed open by water pressure, and is discharged from the discharge port 22 to the ground side.

[0064] Thereafter, the water level in the hollow pipe 11 drops, and in the outflow hole 14 located at a position higher than the water level in the hollow pipe 11, as shown in FIG. 11(B), since there is no water on the intake 21 side of the weep hole 20 provided in this outflow hole 14, the float valve 24, which is no longer acting on buoyancy, sits on the valve seat 25 by gravity and closes the flow path. In addition, since the water pressure from the intake 21 side does not act on the main check valve 23, the main check valve 23 closes the flow path. This blocks the flow of water through the weep hole 20. Furthermore, even if the inside of the hollow pipe 11 is pressurized by the operation of the pressurizing pump 41, the float valve 24 closes the flow path, so that the air in the hollow pipe 11 is prevented from leaking to the ground side through the weep hole 20, and the operating efficiency of the pressurizing pump 41 can be prevented from decreasing.

[0065] In addition, at the outflow hole 14 located below the water level in the hollow pipe 11, water flows out to the ground side through the weep hole 20 as described above.

[0066] [Second embodiment example] In the above-mentioned underground structure 1, the retaining structure 2 (side wall 3) constructed using the hollow pipe 11 can be used by itself as an earth retaining structure with flood control functions, so examples of its use will be described in detail from the second embodiment onwards.

[0067] The second example shown in Figure 12 is an example in which side walls 3 are constructed by installing the retaining structure 2 with flood control function in a closed shape when viewed in a plane, a lower deck 4 is provided inside the interior surrounded by the side walls 3, and an upper deck 6 is provided above the side walls 3 to seal off the interior surrounded by the side walls 3, and the above-ground portion of the underground structure 1 is used as a road, railway line, park, parking lot, etc.

[0068] In this way, the aboveground portion of the underground structure 1 can be effectively utilized as a road, etc., and at the same time, the underground portion of an existing road, etc. can be utilized to construct the underground structure 1, thereby improving flood control and water utilization.

[0069] [Third embodiment] The third example shown in Figure 13 is an example in which, when the construction of a retaining structure on a cut surface would block the flow of groundwater, the retaining structure is made to have a flood control function according to the present invention so as not to impede the flow of groundwater.

[0070] Specifically, hollow pipes 11, 11... are installed horizontally adjacent to each other in the ground, and the gaps between these hollow pipes 11, 11... are filled with solidifying material 12 to stop water leaks. Water passage holes are formed in the pipe wall of the hollow pipe 11 in a pattern forming water inlet holes 13, 13... and outlet holes 14, 14.... Permeable layers 15, 15 are formed along the depth direction of the ground on the outer side of the hollow pipe 11 with these inlet holes 13 and outlet holes 14 formed, i.e., on both sides in the direction of the groundwater flow.

[0071] The hollow pipe 11 is provided with an inlet 13 and an outlet 14 for groundwater, and permeable layers 15, 15 are formed on the ground surface side of these water holes. Therefore, even if a viscous layer N (impermeable layer) is present in the ground, water can flow through the permeable layer 15 as a water flow channel, and since the groundwater flows through the inlet 13 and outlet 14, the flow of groundwater is not blocked by the retaining structure 2.

[0072] [Fourth embodiment] The fourth example shown in Figure 14 is an example in which the retaining structure is constructed as a landslide prevention wall in the ground as an earth retaining structure 2 equipped with flood control function according to the present invention so as not to impede the flow of groundwater when the flow of groundwater is blocked by the construction of the retaining structure in the ground.

[0073] In this case, as in the third embodiment, water passage holes are formed in the pipe wall portion of the hollow pipe 11 in a pattern forming water inlet holes 13, 13... and outlet holes 14, 14..., and permeable layers 15, 15 are formed along the depth direction of the ground on the outer side of the hollow pipe 11 in which these inlet holes 13 and outlet holes 14 are formed, i.e., on both sides in the direction of groundwater flow.

[0074] The hollow pipe 11 is provided with an inlet 13 and an outlet 14 for groundwater, and permeable layers 15, 15 are formed on the ground surface side of these water holes. Therefore, even if a viscous layer N (impermeable layer) is present in the ground, water can flow through the permeable layer 15 as a water flow channel, and since the groundwater flows through the inlet 13 and outlet 14, the flow of groundwater is not blocked by the retaining structure 2.

[0075] [Fifth embodiment] The fifth embodiment shown in FIG. 15 is an example of an earth retaining structure 2 that can function as a water collection well.

[0076] Specifically, hollow pipes 11, 11... are installed horizontally adjacent to each other in the ground, and the gaps between adjacent hollow pipes 11, 11 are filled with solidifying material 12 to stop water leaks. Water passage holes are formed in the pipe wall of the hollow pipe 11 in a pattern that forms only water inlet holes 13, 13..., and permeable layers 15, 15 are formed along the depth direction of the ground on the outer side, i.e., both sides, of the hollow pipe 11 with these inlet holes 13 formed.

[0077] Groundwater inlet holes 13 are provided in the hollow pipe 11, and permeable layers 15, 15 are formed on the ground surface side of these water holes, so that even if a viscous layer N (impermeable layer) exists in the ground, the permeable layer 15 can be used as a water flow channel to allow water to flow, and groundwater can flow into the hollow pipe 11 from all of the inlet holes 13, enabling effective collection of groundwater. The groundwater collected in the hollow pipe 11 is pumped up by the water lifting pump 43 via the filter 44.

[0078] [Other examples] (1) In order to prevent the float valve 24 from sinking due to the water flow that has passed through the upper opening 28c and flowed into the float valve case 28, causing it to seat on the valve seat 25 and stop flowing, it is preferable to provide a rectifying mechanism for the water that has flowed into the float valve case 28 inside the upper opening 28c. As shown in Fig. 16, examples of the rectifying mechanism include (A) a louver or (B) a hood near the outlet of the upper opening 28c, which can prevent the water flow that has passed through the upper opening 28c from directly hitting the float valve 24.

[0079] (2) In order to prevent the float valve 24 from being pulled in by the water flow passing through the vertical communication port 28b and seating on the valve seat 25 to stop the water flow, the float valve 24 can be formed in a shape that exerts a small resistance to the water flow, for example, (A) a spherical shape, (B) an egg shape, or (C) a rugby ball shape, as shown in Fig. 17. In the case of the (A) spherical shape, the upper surface of the valve seat 25 can be made into an inclined surface that slopes downward toward the center of the vertical communication port 28b, so that the spherical float valve 24 can easily return to the center of the valve seat 25 by gravity when buoyancy is no longer acting. [Explanation of symbols]

[0080] 1...underground structure, 2...earth retaining structure, 3...side wall, 4...lower deck, 5...storage space, 6...upper deck, 7...hollow pipe for pumping, 9...rainwater inlet, 10...vacuum pump, 11...hollow pipe, 12...solidification material, 13...inlet, 14...outlet, 15...permeable layer, 16...pre-boring hole, 17a, 17b...ribbed strip, 20...weep hole, 21...intake, 22...outlet, 23...main check valve, 24...float valve, 25...valve seat, 26...casing, 27...partition plate, 28...float valve case, 29...packing, 30...seat plate, 31...fixing screw, 33...easily deflected section, 35...filter, 40...vacuum pump, 41...pressurizing pump, 42...drainage pump, 43...lifting pump, 44...filter

Claims

1. A weep hole is characterized by having a main check valve that allows water to flow only from the intake to the discharge outlet and prohibits water from flowing in the opposite direction, and also having a float valve upstream of the main check valve that opens the flow path using buoyancy while water is passing through, and closes the flow path when the main check valve is closed to prevent air from flowing from the intake to the discharge outlet.

2. 2. The weep hole according to claim 1, wherein a filter is provided at either or both of the water intake and the water discharge.

3. 2. The weep hole according to claim 1, wherein the main check valve is a swing-type check valve that swings toward the water outlet.

4. A retaining structure in which hollow pipes are installed horizontally adjacent to each other in the ground, A solidification material is filled in the gaps between the horizontally adjacent hollow tubes to prevent water leakage. Water passage holes are formed in a pipe wall portion of the hollow pipe in any one of a pattern in which only a water inlet hole is formed, a pattern in which only a water outlet hole is formed, and a pattern in which both a water inlet hole and a water outlet hole are formed; A retaining structure, characterized in that each of the water holes is provided with a weep hole as described in any one of claims 1 to 3.

5. 5. The retaining structure according to claim 4, further comprising either or both of a vacuum pump for creating a negative pressure inside the hollow pipe and a pressure pump for pressurizing the inside of the hollow pipe.

6. An underground structure in which a side wall is constructed by installing an earth retaining structure in which hollow pipes are installed horizontally adjacent to each other in the ground in a closed shape in a plan view, and a planar underground space is formed by constructing at least the lower floor slab within an area surrounded by the side wall, A solidification material is filled in the gaps between the horizontally adjacent hollow tubes to prevent water leakage. Water passage holes are formed in a pipe wall portion of the hollow pipe in any one of a pattern in which only a water inlet hole is formed, a pattern in which only a water outlet hole is formed, and a pattern in which both a water inlet hole and a water outlet hole are formed; An underground structure, characterized in that each of the water holes is provided with a weep hole as described in any one of claims 1 to 3.

7. 7. An underground structure according to claim 6, further comprising either or both of a vacuum pump for creating a negative pressure inside said hollow pipe and a pressure pump for pressurizing said hollow pipe.

8. The underground structure according to claim 6, further comprising an upper deck above the side wall, which seals off the interior enclosed by the side wall.

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