JP5616678B2 - Underdrain, groundwater drainage structure and drainage network using this - Google Patents

Description

  The present invention relates to a culvert buried in the ground for collecting and draining groundwater, a groundwater drainage structure using the same, and a drainage network.

  2. Description of the Related Art Conventionally, there is known a fixed culvert having an opening communicating with the inside of a pipe on an upper surface and a pair of projecting portions erected so as to sandwich the opening (see Patent Document 1). A plurality of the culverts are buried in the ground in a plurality connected in the longitudinal direction, and groundwater guided by an arbitrary water collecting means (water permeable material or the like) buried in the upper side is collected on the upper surface thereof. The groundwater collected on the upper surface is guided to the opening by a pair of protrusions, and further flows down to the internal channel of the underdrain to be drained.

JP 2009-215872 A

  By the way, the connection portion (joint portion) between the underdrain and the underdrain has sufficient “joint allowance” in consideration of earthquake resistance and the like, and the drainage (groundwater) does not leak from this portion. However, in the above-described conventional underdrain, when the groundwater that has flowed down flows on the upper surface according to the gradient, a part of the groundwater is exposed to the outside from a slight gap of the joint portion (abutting each other's small edge portion) where each protrusion does not exist. There was a problem that the groundwater could not be effectively introduced into the inside of the culvert and the water collection efficiency was lowered. In particular, after a culvert is buried, when a slight drop occurs in the joint due to ground subsidence, earthquake, or the like, the outflow of the groundwater collected on the top surface of each culvert becomes significant.

  This invention makes it a subject to provide the underdrain which can suppress the outflow from the small edge part of the groundwater collected on the upper surface, the drainage structure of a groundwater using this, and a drainage network.

The underdrain of the present invention is a underdrain buried under the groundwater conduit structure constructed in the ground and collects and drains the groundwater flowing down from the conduit structure, and penetrates in the extending direction and drains. A culvert body with a channel formed therein, a water collection opening for communicating the upper surface of the culvert body with the drainage channel, a water return portion projecting over the entire circumference of the upper surface of the culvert body, A protruding protrusion formed in one of the small openings and connected to the drainage flow path; and a bonding recess formed to be immersed in the other small opening and connected to the drainage flow path. It is formed in the stepped taper shape which has a part .

  According to this configuration, the upper surface of the culvert body on which the water return portion is installed serves as a groundwater receiver that is guided to the water conveyance structure, and the groundwater collected on the upper surface of the culvert body is a water collection opening on the upper surface. It flows into the drainage channel through the opening. That is, the groundwater collected inside the water return portion provided for each underdrain flows down into the drainage channel without leaking from the upper surface of the underdrain main body. In this case, the water return section is provided not only in the direction in which the culvert body extends, but also in the direction of the culvert, and groundwater collected on the top surface of the culvert body leaks from the mutual culverts of adjacent culverts and is again grounded. It can be surely prevented from flowing out. In particular, even if the adjacent culverts are slightly separated due to a subsequent factor such as an earthquake, it is possible to appropriately prevent the outflow of groundwater from the small edge portion. Therefore, groundwater collection efficiency does not decrease. Furthermore, since the water return structure faces the upper surface of the culvert body where the water return section is installed, the water return section regulates the horizontal movement (positional displacement) of the water guide structure. A positional shift between the water guiding structure and the culvert body due to pressure or the like can be suppressed. On the other hand, the water return portion in the fore edge direction functions as a beam with respect to the load of the water guiding structure from above, earth pressure, etc., so that the strength of the entire underdrain can be increased. In consideration of die cutting when manufacturing a culvert, the water collection opening has a narrowed shape facing downward.

  In addition, you may project a water return part in the edge direction of the downstream of the drainage gradient of a culvert, and the extending direction of the both sides | surfaces of the said culvert main body of the said downstream. That is, you may provide a water return part only in the downstream of the drainage gradient of a culvert. In this case, the collected groundwater is prevented from flowing out from the upper surface of the culvert body by the water return portion disposed only on the downstream side of the drainage gradient. This configuration is particularly effective when the drainage gradient of the underdrain is large.

  In this case, the inner side surface of the water return portion is configured by an inclined surface that is inclined downward toward the water collection opening, and the outer side surface of the water return portion is flush with the upper portions of the side surfaces of the underdrain main body and the upper portions of the small edge surfaces. Preferably it is formed.

  According to this configuration, the surface receiving groundwater, that is, the water collecting area can be secured as wide as possible, and the groundwater flowing down to the upper surface can be collected efficiently without leakage. In addition, it is good also as a shape which widened the part from the upper part of a culvert main body to a water return part in a cross-sectional direction.

Similarly, the inner side surface of the water return portion is composed of an inclined surface that is inclined downward toward the water collection opening, and the outer side surface of each extending direction portion of the water return portion is flush with the upper side surfaces of the underdrain main body. It is preferable that the outer side surface of each small-mouth direction portion of the water return portion is formed of an inclined surface that is inclined downward toward the outside.

  According to this configuration, even when the adjacent culverts are bent at the junctions of adjacent culverts due to uneven settlement of the ground and deformed into a “V” shape, the outer surface of the water return portion on the small edge side is inclined outward. Therefore, the water return portions of the culverts of each culvert are in contact with each other, and stress concentration does not occur in this portion. Thereby, the water return part of each small edge surface does not break. In addition, when deformed into a “V” shape, the lower side of the adjacent culvert junction part is separated, but it is difficult for the water return portions to contact each other at the adjacent culvert junction part. The lower side separation (extraction) can be minimized. Furthermore, by tilting the inner surface of the water return portion toward the water collection opening side, not only is it easy to remove the mold when manufacturing the underdrain, but it is possible to ensure the structural strength of the water return portion. it can.

  In this case, it is preferable that a plurality of water collection openings are arranged in parallel to each other along the extending direction.

  According to this structure, the ratio of the water collection opening part with respect to the water collection area of groundwater can be enlarged, and the drainage efficiency of the collected groundwater can be improved.

  In this case, it is preferable to further include a longitudinal projecting portion that is positioned between the plurality of water collecting openings and projects from the upper surface of the culvert body, and connects between the two fore-edge portions of the water return portion.

  According to this configuration, since the longitudinal projecting portion protruding from the upper surface of the culvert body functions as a girder, a culvert with high strength against earth pressure (particularly from above) can be configured.

  Moreover, in this case, it is preferable that a non-opening portion in which no water collection opening portion is present is disposed on at least both small mouth sides of the upper surface of the culvert body.

By the way, if the water collection opening is large, the drainage efficiency of the groundwater collected on the upper surface of the culvert body will be better. is there.
However, according to this structure, a non-opening part becomes a support and it can prevent that a culvert main body bends to the inside of a drainage flow path by earth pressure (so-called pausing). Thereby, in order to secure the strength of the underdrain, it is not necessary to increase the amount of reinforcing bars, and it is not necessary to increase the thickness of the underdrain main body (body), so that the cost of underdrain manufacture can be reduced. And it is possible to construct a culvert that achieves both high pressure resistance and good drainage efficiency.

In this case , the non- opening portion is composed of a convex-side non-opening portion positioned on the bonding convex portion side and a concave-side non-opening portion positioned on the bonding concave portion side. The distance between the end and the end of the water collecting opening on the bonding convex side, the distance between the back end of the bonding concave and the end of the water collecting opening on the bonding concave side in the non-opening on the concave side, Are preferably formed at the same distance in the extending direction.

  According to this configuration, the convex-side non-opening portion and the concave-side non-opening portion disposed on both small-mouthed sides of the culvert body function as beams and slabs, so the culvert main body against the earth pressure from above and both sides Sufficient strength can be secured. In addition, it is possible to maintain a good balance between the pressure-resistant strengths on the bonding convex portion side and the bonding concave portion side, and it is possible to prevent minute distortion and stress concentration of the culvert body.

  In this case, it is preferable that the water collection opening has a plurality of individual openings arranged in the extending direction with an intermediate non-opening between them.

  According to this configuration, the pressure resistance of the culvert can be secured high while maintaining the drainage performance of the groundwater from the top surface of the culvert body to the drainage channel. Thereby, the overflow of groundwater from a water return part (especially the water return part by the side of a small mouth) can be prevented, and high water collection efficiency can be maintained. Moreover, since the non-opening part between adjacent individual opening parts functions as a beam of both side walls, the pressure-resistant strength of the culvert body can be maintained high.

  In this case, it is preferable to further include a transverse projecting portion that protrudes from the upper surface of each intermediate non-opening portion and connects between the two extending direction portions of the water return portion.

According to this configuration, since the upper surface of the culvert body is subdivided in the gradient direction (extending direction) by forming a plurality of transverse protrusions, in each range surrounded by the water return part and the transverse protrusions The absolute value of the vertical distance of the gradient becomes smaller. Therefore, even when the culvert is arranged at a steep slope, overflowing into each range surrounded by the water return portion and the transverse projection portion while keeping the height (projection amount) of the water return portion and the transverse projection portion low. It is possible to store a predetermined amount of groundwater while preventing the above. Thereby, even if the opening area of each individual opening which is disadvantageous to the structure (strength) of the underdrain is reduced, the collected groundwater can be drained to the drainage channel without leakage. Further, by forming the water return portion and the transverse projecting portion low, it is easy to perform die cutting when manufacturing the underdrain.
Furthermore, since the transverse projecting portion functions as a beam on the upper surface of the culvert body, the direction perpendicular to the extending direction (drainage channel direction) and above without reinforcing (increasing costs) such as increasing the amount of reinforcing bars. A culvert with a high withstand pressure strength can be configured.

  In this case, the plurality of individual openings are preferably arranged so that the distances between the individual openings are equal.

  According to this configuration, by arranging a plurality of individual openings in a balanced manner on the top surface of the culvert body, the pressure resistance strength of the entire culvert can be made uniform. In addition, by disposing the plurality of individual openings at equal intervals, the drainage capacity does not change regardless of which direction the culvert extends in the upstream side (or downstream side) of the gradient. Thereby, since it is not necessary to change the arrangement of the individual openings depending on the direction of the gradient, it is possible to reduce the burden and cost related to the design and manufacture of the underdrain. Furthermore, the contractor can carry out the burial work without worrying about the direction of the culvert (reducing the burden on the builder).

  In this case, in the extending direction, the length of the water collection opening is preferably 10% to 95% of the total length ratio of the drainage channel.

  According to this configuration, it is possible to configure a culvert that has both high pressure resistance and good drainage efficiency.

  In this case, it is preferable that both side surfaces of both sides of the undercarriage body are respectively embedded with fore end side insert nuts to which a joining member for maintaining a joined state with the adjacent undercarriage is bolted.

  According to this structure, the joining state between culverts is maintained by fixing a joining member to each small edge side insert nut of adjacent culverts. Thereby, it is possible to reduce the risk that the other culvert will escape more than necessary from one culvert at the junction between the culverts due to an earthquake or the like that occurred after embedding. In addition, it is preferable that the joining of adjacent culverts is made in a state in which it is allowed to come out within an allowable range (a range where water does not leak). Moreover, it may replace with a small edge side insert nut and may embed an insert screw (bolt) etc. in a culvert main body.

  In this case, the water conveyance structure has a void member that constitutes a void for water conveyance, and a fixing member for fixing the lower end portion of the void member so as to face the water collection opening on the upper surface of the culvert body is a bolt. The upper insert nut to be fastened is preferably embedded.

  According to this configuration, since the gap member is fixed on the water collection opening through the fixing member bolted to the upper surface insert nut, the groundwater collected through the gap member is appropriately guided to the upper surface of the culvert body. And flows into the drainage channel through the water collection opening. In place of the upper surface insert nut, an insert screw (bolt) or the like may be embedded in the upper surface of the culvert body.

  The groundwater drainage structure of the present invention is characterized by including the above-described underdrain and a water guide structure.

In this case, the water guide structure is disposed between the pair of wall bodies placed in parallel to each other along the extending direction on the water return portion of the culvert, and the water guide structure . has a gap member that constitutes the gap, a, and, while being buried in the extending direction of the culvert, which is preferably embedded so as damming groundwater.

  According to these configurations, a wide range of groundwater can be collected and drained efficiently. In particular, since groundwater flows mainly along the boundary between the natural ground and the embankment, the efficiency of collecting groundwater can be improved by burying the culvert near the boundary. Thereby, groundwater can be excluded exactly and the stability of the ground can be improved. Moreover, a wall body is mounted on the water return part, and the bottom face of a wall body bites into a water return part. Thereby, a wall (water conveyance structure) is fixed, without shifting | deviating to a horizontal direction (direction orthogonal to the extending direction).

Drainage network of groundwater of the present invention, the underdrain line formed by lined several drainage structure of groundwater as described above, a catch basin which is interposed in a main inspection positions of chosen and becomes underdrain line, further comprising a Features.

  According to this configuration, the drainage structure can be flexibly constructed according to the terrain, and the maintenance and management (clogging prevention / inspection etc.) of the underdrain drainage line can be performed by the appropriately disposed drainage tank. As the location of the drainage basin, for example, it may be arranged between one culvert drainage line and another culvert drainage line, a corner portion, or other culvert drainage line at a predetermined interval.

It is the schematic diagram which showed the burial range of the drainage network of this invention. It is sectional drawing which showed typically the drainage structure which concerns on 1st Embodiment of this invention. It is the perspective view which showed typically the underdrain drainage line which concerns on 1st Embodiment of this invention. It is a four-plane figure of the underdrain (long tube type) concerning a 1st embodiment of the present invention. It is a fragmentary top view for demonstrating attachment of the convex part end surface member which obstruct | occludes the end surface of a culvert, and a recessed part end surface member. (A) is a top view of a joining member, (b) is sectional drawing of the fixing member and space | gap member fixed to the upper surface of the culvert body. It is the top view and side view which showed the modification of the underdrain which concerns on 1st Embodiment. It is a four-sided view showing another modification of the underdrain according to the first embodiment. It is the top view and side view which showed the short tube type underdrain which concerns on 1st Embodiment. It is the top view and side view which showed the curved pipe type culvert concerning 1st Embodiment. It is the top view and side view of a culvert (long tube type) concerning a 2nd embodiment of the present invention. It is the top view and side view of a culvert (long tube type) concerning a 3rd embodiment of the present invention. It is the top view and side view of a culvert (long tube type) concerning a 4th embodiment of the present invention. It is the top view and side view of a culvert (long tube type) concerning a 5th embodiment of the present invention.

  Hereinafter, the underdrain according to the first embodiment of the present invention will be described with reference to the accompanying drawings. This underdrain is used for a drainage network that collects and drains groundwater that has flowed down from a water-conducting structure built in the ground on its upper surface. First, the groundwater drainage network will be described.

  As shown in FIG. 1 to FIG. 3, the groundwater drainage network 1 includes a culvert drainage line 2 buried in the embankment H buried on a natural ground M, which is the original ground surface, and an essential point of each culvert drainage line 2. And a plurality of drainage basins 3 interposed at the inspection position. On the embankment H buried in the valley, a residential land E is created, and a road R is provided so as to surround each residential land E. A drainage network 1 (underdrain drainage line 2) is buried directly under the road R provided at the peripheral edge of the embankment H. The plurality of drainage basins 3 are provided at points requiring inspection such as corners, junctions, long straight portions, or portions where the drainage gradient changes extremely in the underdrain drainage line 2. The drainage basin 3 arranged in this way enables the drainage network 1 to be maintained and managed (clogging prevention, inspection, etc.).

  The culvert drainage line 2 is composed of a culvert 5 and a groundwater drainage structure 4 having a water guide structure 6 that collects groundwater in the culvert 5. The underdrain drainage line 2 is constructed by connecting a plurality of drainage structures 4 in a wide range according to the topography of the valley bottom of the natural mountain M, and mainly processes the groundwater flowing down from the mountain side of the natural mountain M. The downstream end of the underdrain drainage line 2 is connected to a river or the like so that the collected groundwater can be discharged into the river or the like. On the other hand, end portions on the upstream side are closed by end surface members 83 and 84 (see FIG. 5) so that dirt and the like do not enter. A drainage basin 3 may be provided at the upstream end.

The groundwater mainly flows along the boundary between the natural ground M and the embankment H, and accumulates in the embankment H up to the water level line indicated by the symbol L1 in FIG.
Therefore, in this embodiment, the underdrain 5 constituting each drainage structure 4 is embedded in the boundary portion (including the vicinity of the boundary) between the natural ground M and the embankment H, so that the boundary between the natural ground M and the embankment H is mainly used. It is possible to efficiently collect and drain groundwater flowing along. Thereby, the water level of groundwater falls to the water level line shown by the code | symbol L2 of FIG. 2, groundwater does not accumulate in the embankment H, and the embankment H can be stabilized.

  The water guide structure 6 includes a pair of sandbag walls 61 formed by laminating a plurality of sandbags 62 embedded in the embankment H, and a gap member 63 disposed so as to be sandwiched between the pair of sandbag walls 61. have. A roadbed F and a pavement S are formed on the embankment H, and the road R is formed.

  The pair of sandbag walls 61 are respectively placed on water return portions 54 (details will be described later) projecting on both sides of the upper surface of the underdrain 5 along the extending direction of the underdrain 5, and each has a predetermined gap. Have a confrontation. That is, the pair of sandbag walls 61 dams groundwater flowing mainly from the upstream of the ground mountain M along the direction of the drainage gradient (extending direction) of each underdrain 5 on the mountain side and the valley river of the ground mountain M, respectively. It is buried in.

  Each sandbag 62 is filled with excavated soil excavated when the sandbag wall 61 is buried. The sandbag wall 61 (sandbag 62) is preferably made of a material having higher water permeability than the embankment H, and instead of excavated soil (other soil), waste material, plastic, and other substitutes are transferred to the sandbag 62. It is good also as a storage thing.

  In the gap between the sandbag wall 61 and the sandbag wall 61, a gap member 63 that constitutes a gap for water conveyance is sandwiched. The gap member 63 only needs to be a material having higher water permeability than the embankment H, and is composed of, for example, a resin water-permeable material, crushed stone, and a hollow structure. As described above, the gap member 63 is sandwiched between the pair of sandbag walls 61, so that a predetermined gap between the pair of sandbag walls 61 is secured, and the groundwater in the embankment H can be effectively absorbed (collected). . Further, the lower end portion of the gap member 63 is fixed to a position facing the upper surface (water collecting opening 52) of the underdrain 5 by a plurality of fixing members 85 (details will be described later) disposed on the upper surface of the underdrain 5. Yes. Thereby, the groundwater flowing down through the gap member 63 is reliably guided to the underdrain 5.

  Next, the underdrain 5 will be described in detail with reference to FIGS. 4 to 10. Hereinafter, in order to simplify the description, the straight pipe type underdrain 5 used when the underdrain drainage line 2 is configured straight will be described. In the following, in each figure, the longitudinal direction of the underdrain 5 is the “X-axis direction”, the direction orthogonal to this is the “Y-axis direction”, and the direction orthogonal to the X-axis direction and the Y-axis direction is “Z-axis direction” ”And explained. As shown in FIG. 4, the underdrain 5 includes an underdrain main body 51 in which a drain passage 71 is formed penetrating in the X-axis direction, and a water collection opening 52 that allows the upper surface of the underdrain main body 51 and the drain passage 71 to communicate with each other. And a water return portion 54 projecting over the entire circumference of the upper surface of the culvert body 51.

  The underdrain main body 51 has a substantially rectangular parallelepiped appearance, and a drain passage 71 having a circular cross section is formed through the X-axis direction at a substantially central portion of the rectangular cross section. In addition, the cross-sectional shape of the drainage channel 71 is not limited to a circle, and may be a rectangle, an ellipse (egg), or the like.

  Further, the underdrain main body 51 includes a joint convex portion 72 that protrudes from one of the small openings and communicates with the drainage flow channel 71, and a joint concave portion 73 that is formed to be immersed in the other small mouth and communicates with the drainage flow passage 71. Yes. The joining convex part 72 is formed in the taper shape with the step which has the step part 72a. An annular water stop rubber (not shown) is fitted to the joint convex portion 72, and the water stop rubber is in contact with the stepped portion 72a. On the other hand, the bonding recess 73 is formed in a tapered shape that is substantially complementary to the bonding protrusion 72.

  Connection (joining) between the underdrains 5 is performed by fitting the joining convex portion 72 in one underdrain 5 to the joining concave portion 73 in the other underdrain 5. Thereby, the joint convex part 72 and the joint recessed part 73 closely_contact | adhere in the water stop rubber part, and each underdrain 5 is mutually joined in a water stop state. The joint portion between the underdrains 5 is configured so that the water stop performance is not deteriorated even when the joint convex portion 72 is slightly pulled out from the joint concave portion 73 (about several mm to several cm) due to an earthquake or the like, and A sufficient “joining allowance” (about 60 mm in this embodiment) is secured. That is, it has a structure (insertion type) that allows for withdrawal within an allowable range of several mm to several cm. In addition, when joining, the length of the joint convex part 72 is formed slightly shorter (several mm) than the length of the immersion part of the joint concave part 73 so that the fore edge surface between the undercuts 5 may be in close contact. . Moreover, the inclination angle of each taper of the joining convex part 72 and the joining recessed part 73 is designed so that the die cutting at the time of manufacture of the undercarriage 5 and the joining operation of the undercarriage 5 may be facilitated.

  Also, a plurality of forehead side insert nuts 74 to which a joining member 81 for maintaining a joined state with the adjacent undercarriage 5 is bolted are embedded in both side surfaces of the undercarriage body 51 on both fore edge sides. The fore edge insert nuts 74 are arranged in two places in the Z-axis direction on each side surface.

  As shown in FIG. 5, in the underdrain 5 located at the upstream end of the underdrain drainage line 2, a plurality of end face insert nuts 75 are embedded in the small edge surface on the joining convex portion 72 side or the joining concave portion 73 side. And the convex part end surface member 83 or the concave part end surface member 84 is engaged with the joint convex part 72 side or the joint recessed part 73 via the water stop member 82 (annular water stop rubber), and each end face insert nut 75 is bolted. By fixing with, the joint convex part 72 side or the joint concave part 73 side is closed. In this case, the small-side insert nut 74 on the side closed by the end face members 83 and 84 is omitted. Needless to say, each of the small edge side insert nuts 74 and each of the end face insert nuts 75 is embedded in the underdrain 5 by pouring concrete in a state of being set in a mold (temporary frame) when the underdrain 5 is manufactured.

  As shown in FIG. 6A, the joining member 81 is a plate-like member formed in a metal rectangle, and a pair of holes through which the bolt passes are opened at both ends thereof. The joining member 81 is each fixed with the volt | bolt with respect to the edge side insert nut 74 of each adjacent culvert 5 (refer FIG. 3). That is, the joining between the adjacent culverts 5 is performed by bolting the four joining members 81 to the respective small edge side insert nuts 74. Of the pair of holes, one hole is formed in a circular shape, and the other hole is formed in an elliptical shape having long sides in the X-axis direction. Since one of the holes of the joining member 81 is formed in an elliptical shape, it is allowed to slip out between the adjacent underdrains 5 within a permissible range (a range where no water leaks). Thereby, while being able to give flexibility to a joined part, even if the deformation (earthquake etc.) of the ground where an escape larger than an allowable range may arise should an escape beyond an allowable range be prevented effectively. . In addition, the arrangement | positioning number of the small edge side insert nut 74 and each end surface insert nut 75 is arbitrary, and the material and shape of the joining member 81 are also arbitrary. Further, instead of the fore edge insert nut 74 and each end face insert nut 75, an insert screw (bolt) or the like may be embedded in the underdrain main body 51.

  Moreover, as shown in FIG. 4, the upper insert nut 76 by which the fixing member 85 for fixing the lower end part of the space | gap member 63 so that it may face on the water collection opening part 52 is bolted on the upper surface of the culvert main body 51. Are embedded. The plurality of upper insert nuts 76 are embedded at equal intervals along the X-axis direction in portions where the water collecting openings 52 escape from both ends in the Y-axis direction. Note that the number of the upper insert nuts 76 is arbitrary. Although a detailed description is omitted, a mounting jig 77 for mounting a sling jig (ring jig) is embedded in the upper surface of the culvert body 51.

  As shown in FIG. 6B, the fixing member 85 is an L-shaped metal fitting, and is fixed to each upper insert nut 76 with a bolt so that the gap member 63 facing the water collection opening 52 is arranged in the Y-axis direction. It is arranged so as to be sandwiched from both side surfaces. The gap member 63 is fixed to the plurality of fixing members 85 by screwing nuts into bolts penetrating from one side in the Y-axis direction. Thus, since the gap member 63 is fixed so as to face the water collection opening 52 via the upper insert nut 76 and the fixing member 85, the groundwater collected through the gap member 63 is appropriately culvert body 51. And flows into the drainage flow path 71 through the water collection opening 52. In place of the upper insert nut 76, an insert screw (bolt) or the like may be embedded in the upper surface of the culvert body 51.

  As shown in FIG. 4, the water collection opening 52 has a plurality of individual openings 52 a penetrating from the upper surface of the culvert body 51 to the drainage flow channel 71. And the upper surface of the culvert body 51 where each individual opening 52a does not exist is a non-opening 53. In the present embodiment, four individual openings 52 a that are open in a rectangular shape in plan view are arranged in a line along the X-axis direction at the center in the Y-axis direction on the top surface of the culvert body 51. Thus, by having the plurality of individual openings 52a, the drainage performance of the groundwater from the upper surface of the culvert body 51 to the drainage channel 71 can be maintained high, and the pressure resistance of the culvert 5 can be secured high. Thereby, the overflow of the ground water from the water return part 54 (especially the edge direction part 54a) can be prevented, and high water collection efficiency can be maintained.

  Each individual opening 52a opens in a narrowed shape from top to bottom. In this way, by making the water collecting opening 52 constricted downward, it becomes easy to perform die cutting when manufacturing the underdrain 5.

In addition, since the shape and the number of formation of the water collection opening part 52 (individual opening part 52a) are arbitrary and at least 1 should just be formed, the structure as shown in FIG. 7 may be sufficient, for example. Although not shown in the figure, a plurality of water collection openings 52 along the X-axis direction may be formed side by side in the Y-axis direction, or the individual openings 52a may be formed in a matrix or zigzag, By forming the water collecting openings 52 (individual openings 52a) large or (and) a large number, the drainage efficiency of the groundwater becomes good.
However, when the opening portion of the water collecting opening 52 with respect to the upper surface of the culvert body 51 is enlarged, there is a problem that the structural strength of the culvert 5 is reduced. In this embodiment, the non-opening portion 53 is provided, By using it as a support, the underdrain main body 51 is prevented from bending to the inside of the drainage flow channel 71 due to earth pressure (so-called patronage). Thereby, in order to secure the strength of the underdrain 5, it is not necessary to increase the amount of reinforcing bars, and it is not necessary to increase the thickness of the underdrain main body 51 (an underbody). Can do.

  The non-opening portion 53 is an upper surface of the culvert body 51 where the individual opening portions 52a do not exist, and is positioned on the joint convex portion 72 side with a plurality of intermediate non-opening portions 53a provided between the individual opening portions 52a. It has a convex part-side non-opening part 53b and a concave part-side non-opening part 53c located on the bonding concave part 73 side. Since the non-opening 53 functions as a beam on both side walls, the pressure-resistant strength of the culvert body 51 can be maintained high. In the case of the underdrain 5 having the configuration as shown in FIG. 7, the intermediate non-opening 53a does not exist due to the configuration.

  The plurality of intermediate non-opening portions 53a (three in the present embodiment) are formed to have the same length in the X-axis direction. That is, the individual openings 52a are arranged at equal intervals. As a result, the plurality of individual openings 52a are arranged in a well-balanced manner on the upper surface of the culvert body 51, so that the pressure resistance strength of the entire culvert 5 can be made uniform, and both high pressure resistance strength and good drainage efficiency are achieved. The culvert 5 can be configured. In addition, by disposing the plurality of individual openings 52a at equal intervals, the drainage capacity does not change regardless of which side of the culvert 5 is located upstream (or downstream) of the gradient. Thereby, since it is not necessary to change arrangement | positioning of the separate opening part 52a according to the direction of a gradient, the reduction of the burden and cost concerning the design and manufacture of the underdrain 5 can be aimed at. Furthermore, the builder can perform the burial work of the culvert 5 without worrying about the direction of the culvert 5 (reduction of the burden on the builder).

  In the present embodiment, the distance between the base end of the joint convex portion 72 and the end of the water collecting opening 52 on the joint convex portion 72 side in the convex portion-side non-opening portion 53b ("A" in FIG. 4). Display) and the distance (indicated as “A ′” in FIG. 4) between the back end of the joint recess 73 and the end of the water collection opening 52 on the joint recess 73 side in the recess-side non-opening 53c. They are formed at the same distance in the extending direction. Thereby, since the convex part side non-opening part 53b and the concave part side non-opening part 53c which are arrange | positioned in the both small edge side of the culvert body 51 function as a beam or a slab, the culvert body 51 with respect to the earth pressure from the upper direction and both sides It is possible to ensure sufficient strength. Further, it is possible to maintain a good balance of pressure strength between the joint convex portion 72 side and the joint concave portion 73 side, prevent minute distortion and stress concentration of the culvert body 51, and the joint state between the culverts 5. It can be maintained well.

  In detail, each fore edge portion 54a (to be described later) of the water return portion 54 is disposed immediately above the convex portion-side non-opening portion 53b on the joint convex portion 72 side, and on the joint concave portion 73 side, It is arranged immediately above the joint recess 73 side. Further, since each intermediate non-opening 53a is formed to have the same length, and the convex-side non-opening 53b and the concave-side non-opening 53c are formed to have the same length, the individual opening 52a on the right side in FIG. Is formed shorter than the other individual openings 52a.

  In the present embodiment, in the X-axis direction, the length of the water collection opening 52 (the total length of the plurality of individual openings 52a) is 10% or more and 95% or less of the total length ratio of the drainage channel 71. It is formed as follows. Thereby, it is possible to configure the underdrain 5 that has both high pressure resistance and good drainage efficiency. In addition, the total length ratio of the drainage channel 71 is more preferably 40% or more and 60% or less.

  The water return portion 54 is provided so as to protrude from the top surface of the culvert body 51 along the outer periphery of the top surface of the culvert body 51, and has a fore edge portion 54 a erected along the Y-axis direction on each fore edge side. These are formed integrally with the extending direction portion 54b erected along the X-axis direction on each side surface side. In this way, the upper surface of the underdrain main body 51 provided with the water return portion 54 serves as a receiver of groundwater guided to the water guide structure 6 (gap member 63), and the groundwater collected on the upper surface of the underdrain main body 51 is The water flows into the drainage flow channel 71 without leaking from the upper surface through the water collection opening 52 (a plurality of individual openings 52a) opened on the upper surface.

  Each fore edge portion 54a has a substantially trapezoidal cross section in which the inner side surface is an inclined surface that is inclined downward toward the water collection opening 52 and the outer side surface is flush with the fore edge surface. Similarly, each extending direction portion 54b has an inner side surface inclined to the water collecting opening 52 side and an outer side surface that is flush with each side surface of the culvert body 51, and has a substantially trapezoidal cross section. Have. Thus, by making each fore edge portion 54a and each extending direction portion 54b have a substantially trapezoidal cross section, not only can the die-cutting when manufacturing the underdrain 5 be facilitated, but also the structure of the water return portion 54 can be improved. Strength can be secured.

  Moreover, since the water return part 54 is provided with the water return part 54 along the outer periphery of the upper surface of the underdrain main body 51, the area which receives groundwater can be ensured maximally, The groundwater that has flowed down can be collected efficiently without leakage. Further, the fore edge portion 54a functions as a beam with respect to the load of the water guide structure 6 from the upper side, earth pressure, and the like, so that the strength of the underdrain 5 as a whole can be increased. In addition, as shown in FIG. 8, in the upper surface of the culvert body 51, the water return part 54 may be provided inward from both side surfaces. However, in consideration of water collection efficiency, it is preferable to provide the water return portion 54 along the outer periphery of the upper surface of the underdrain main body 51 as described above. It is good also as a shape (illustration omitted) which expanded the part from the water return part 54 to.

  Further, the lowermost sandbag 62 of the pair of sandbag walls 61 is placed on the extending direction portion 54b. Since the bottom surface of each bottom sandbag 62 bites into each extending direction portion 54b, the bottom bottom sandbag 62 of each sandbag wall 61 is prevented from being displaced in the Y-axis direction (see FIGS. 2 and 3). . Thereby, the position shift to the Y-axis direction of each sandbag wall 61 can be prevented.

  According to the above configuration, the water return portion 54 is provided not only in the extending direction of the underdrain main body 51 but also in the fore edge direction, and the groundwater collected on the upper surface of the underdrain main body 51 is connected to the adjacent underdrain 5. It is possible to reliably prevent leakage from the small edge portion and outflow into the ground again. In particular, even if the adjacent culverts 5 are slightly separated from each other due to post-mortem factors such as an earthquake, it is possible to appropriately prevent the outflow of groundwater from the fore edge portion. Therefore, groundwater collection efficiency does not decrease. Moreover, since the fore edge portion 54a functions as a beam with respect to the load of the water guiding structure 6 from the upper side, earth pressure, and the like, the overall strength of the underdrain 5 can be increased.

  In addition, in the underdrain 5 of the first embodiment, the water return portion 54 is provided on the outer periphery of the upper surface of the underdrain main body 51. However, the water return portion 54 is located on the downstream side of the underdrain drainage gradient 54a. And an extending direction portion 54b protruding only on the downstream side of the drainage gradient. That is, the fore edge portion 54a on the upstream side of the drainage gradient of the underdrain 5 may be omitted, and the water return portion 54 may be provided only on the downstream side of the drainage gradient. In this case, the collected groundwater is prevented from flowing out from the upper surface of the culvert body 51 by the water return portion 54 disposed only on the downstream side of the drainage gradient. This configuration is particularly effective when the drainage gradient of the underdrain 5 is large.

  In addition to the long tube type (in this embodiment, the length of 2 m), the straight tube type culvert 5 described so far has a half length (length) of the long tube type as shown in FIG. There is also a short tube type underdrain 5 of 1 m). In this short tube type underdrain 5, two individual openings 52 a arranged in a line along the X-axis direction are opened. Except for the numerical aperture of the individual opening 52a, the detailed description is omitted because it is the same as the long tubular type culvert 5. Further, the length of the straight tube type underdrain 5 (length in the X-axis direction) may be arbitrarily set.

  Further, in addition to the straight pipe type culvert 5, there is a curved pipe type culvert 5 as shown in FIG. The curved pipe-shaped underdrain 5 has a circular water collection opening 52 in the approximate center of the upper surface of the underdrain main body 51. In addition, since it is the same as that of the straight pipe type underdrain 5 except for being bent and the shape and numerical aperture of the water collection opening 52, detailed description is omitted. 10 shows the underdrain 5 having a bending angle of 15 °, the bending angle and the bending direction may be arbitrarily set.

  The drainage network 1 of the groundwater is configured according to the topography by forming the culvert drainage line 2 by arbitrarily connecting straight pipe-type (long-pipe type, short-pipe type) and curved pipe-type culverts 5.

(Second Embodiment)
With reference to FIG. 11, the underdrain 5 according to the second embodiment will be described. In addition, description of the component similar to the underdrain 5 concerning 1st Embodiment is abbreviate | omitted.
In this underdrain 5, each fore edge portion 54 a of the water return portion 54 is formed with an inclined surface (hereinafter referred to as a chamfered portion 55) that is not only the inner surface but also the outer surface is inclined downward, and has a trapezoidal cross section. have. Thus, by making each fore edge part 54a into a taper shape, die cutting at the time of manufacturing the underdrain 5 becomes further easier. In addition, by providing the chamfered portion 55 in each fore edge portion 54a, even when the culverts 5 are bent at the joint portions of the adjacent culverts 5 due to uneven settlement of the ground and deformed into a “V” shape, the culverts 5 are mutually connected. The fore edge portion 54a comes into contact, and stress concentration does not occur in this portion. Thereby, each fore edge part 54a is not damaged. In addition, when deformed into a “V” shape, the lower side of the joint portion of the adjacent underdrain 5 will be separated, but it is difficult to contact each other fore edge portion 54a at the joint portion of the adjacent underdrain 5, Separation (extraction) on the lower side of the joint portion can be minimized. As in the case of the fore edge portion 54a, the outer surface of each extending direction portion 54b may be inclined (chamfered).

(Third embodiment)
With reference to FIG. 12, the underdrain 5 according to the third embodiment will be described. In addition, description of the component similar to the underdrain 5 concerning 1st Embodiment is abbreviate | omitted.
The underdrain 5 is formed with two rows of water collecting openings 52 formed of a plurality (four) of individual openings 52a arranged in the Y-axis direction. That is, eight individual openings 52a are formed in a matrix. And between the pair of water collecting openings 52, there is provided a longitudinal projecting portion 56 that protrudes from the upper surface of the culvert body 51 and connects between the two fore edge portions 54a of the water return portion 54. Since this vertical protrusion 56 functions as a girder, it is possible to configure the underdrain 5 having high strength against earth pressure (particularly from above). In addition, when the water collection openings 52 (a plurality of individual openings 52 a) are formed in two or more rows, the vertical protrusions 56 may be formed between any water collection openings 52. For example, when four rows of water collection openings 52 are formed, the longitudinal protrusions 56 may be provided between the respective rows, or may be provided every two rows. Moreover, although the vertical protrusion 56 may be provided at a position that is asymmetric in the left-right direction (Y-axis direction), it is preferably provided at a position that is left-right symmetric in consideration of the weight and the balance of drainage.

(Fourth embodiment)
With reference to FIG. 13, the underdrain 5 according to the fourth embodiment will be described. In addition, description of the component similar to the underdrain 5 concerning 1st Embodiment is abbreviate | omitted.
In the underdrain 5, a transverse projecting portion 57 is provided on the upper surface of each intermediate non-opening portion 53 a of the underdrain 5 according to the first embodiment so as to connect between both extending direction portions 54 b of the water return portion 54. In this way, by forming a plurality of transverse protrusions 57, the upper surface of the culvert body 51 is subdivided in the gradient direction (X-axis direction), so each of the water return portions 54 and the transverse protrusions 57 are surrounded by The absolute value of the vertical distance of the gradient in the range is reduced. Therefore, even when the underdrain 5 is disposed at a steep slope, the water return portion 54 and the transverse protrusion 57 are surrounded by the water return portion 54 and the transverse protrusion 57 in a state where the height (projection amount) of the water return portion 54 and the transverse protrusion 57 is kept low. A predetermined amount of groundwater can be stored in each range while preventing overflow. Thereby, even if the opening area of each individual opening 52a is reduced, the collected groundwater can be drained into the drainage flow channel 71 without leakage, which may be disadvantageous to the structure (strength) of the underdrain 5. Absent. Further, by forming the water return portion 54 and the transverse projecting portion 57 low, it is easy to perform die cutting when manufacturing the underdrain 5. Further, since the transverse projecting portion 57 functions as a beam on the upper surface of the culvert body 51, the culvert 5 having a high withstand pressure strength in the upper direction and the Y-axis direction can be obtained without reinforcing (increasing costs) the amount of reinforcing bars. Can be configured.

(Fifth embodiment)
Moreover, as shown in FIG. 14, it is good also as a structure provided with the vertical protrusion 56 which concerns on 3rd Embodiment, and the transverse protrusion 57 which concerns on 4th Embodiment. Thereby, the underdrain 5 with high pressure strength can be configured while maintaining high groundwater collection efficiency and drainage efficiency.

  Needless to say, the chamfered portion 55 of the second embodiment may be formed in each fore edge portion 54a of the underdrain 5 according to the third to fifth embodiments. The description and illustration of the underdrain 5 according to the second to fifth embodiments described above relate to the long tube type underdrain 5, but constitute the short tube type or bent tube type underdrain 5. You can also.

  1: drainage network, 2: underdrain drainage line, 3: drainage trough, 4: drainage structure, 5: underdrain, 6: water conduit structure, 51: underdrain main body, 52: water collection opening, 52a: individual opening, 53 : Non-opening part, 53a: intermediate non-opening part, 53b: convex part-side non-opening part, 53c: concave part-side non-opening part, 54: water return part, 54a: fore edge part, 54b: extending direction part, 56: Longitudinal protrusion, 57: Transverse protrusion, 61: Sandbag wall, 63: Gap member, 71: Drainage channel, 72: Joint convex part, 73: Joint concave part, 74: Small insert nut, 76: Upper insert nut

Claims (16)

A culvert buried under the water conveyance structure constructed in the ground, collecting and draining the ground water flowing down from the water conveyance structure,
A culvert body with a drainage channel formed through it in the extending direction;
A water collection opening communicating the upper surface of the underdrain main body and the drainage channel;
A water return portion protruding over the entire circumference of the upper surface of the culvert body,
A protruding protrusion formed in one of the small openings of the underdrain main body, connected to the drainage channel, and a recessed portion formed to be immersed in the other outlet, connected to the drainage channel,
The joint protrusion is formed in a stepped taper shape having a step portion with which the water blocking rubber abuts . The inner surface of the water return portion is composed of an inclined surface that is inclined downward toward the water collection opening portion side,
2. The underdrain according to claim 1, wherein an outer side surface of the water return portion is formed flush with an upper portion of each side surface and an upper portion of each fore edge of the underdrain main body. The inner surface of the water return portion is composed of an inclined surface that is inclined downward toward the water collection opening portion side,
The outer surface of each extending direction portion of the water return portion is formed flush with the upper portion of each side surface of the culvert body,
2. The underdrain according to claim 1 , wherein an outer surface of each of the water-feeding portions in the fore edge direction is formed by an inclined surface that is inclined downward toward the outside.   The culvert according to any one of claims 1 to 3, wherein a plurality of the water collection openings are arranged in parallel to each other along the extending direction.   It further includes a longitudinal projecting portion that is positioned between the plurality of the water collecting openings and protrudes from the upper surface of the culvert body, and connects between the fore-edge portions of the water return portion. The culvert according to claim 4.   The culvert according to any one of claims 1 to 5, wherein a non-opening portion in which the water collecting opening portion does not exist is disposed at least on both small mouth sides of the top surface of the culvert body. The non-opening part is composed of a convex part-side non-opening part located on the joint convex part side and a concave part-side non-opening part located on the joint concave part side,
The distance between the base end of the joint convex part and the end of the water collecting opening on the joint convex part side in the convex part side non-opening part, and the depth of the joint concave part in the concave part side non-opening part The underdrain according to claim 6, wherein the distance between the end and the end of the water collection opening on the side of the joint recess is formed at the same distance in the extending direction.   The culvert according to claim 6 or 7, wherein the water collection opening has a plurality of individual openings arranged in the extending direction with an intermediate non-opening between them. .   9. The culvert according to claim 8, further comprising a transverse projecting portion projecting from the upper surface of each intermediate non-opening portion and connecting between both extending direction portions of the water return portion.   The culvert according to claim 8 or 9, wherein the plurality of individual openings are arranged so that distances between the individual openings are equal.   The underdrain according to any one of claims 1 to 10, wherein in the extending direction, the length of the water collection opening is 10% to 95% of a total length ratio of the drainage channel.   The both side surfaces of both sides of the said culvert main body are respectively embedded with fore side insert nuts to which a joining member for maintaining a joined state with the adjacent culvert is bolted. The underdrain according to any one of 11 to 11. The water conveyance structure has a gap member that constitutes a gap for water conveyance,
The upper surface of the culvert body is embedded with an upper insert nut to which a fixing member for fixing the lower end of the gap member is bolted so as to face the water collection opening. The underdrain according to any one of 1 to 12. The underdrain according to any one of claims 1 to 13,
A drainage structure for groundwater, comprising the water guide structure. The water guide structure, on the water flashing portion of the culvert, and a pair of wall bodies, which are parallel to mounted to each other along the extending direction, is disposed between the pair of wall bodies, water guide And a gap member that constitutes a gap for
The groundwater drainage structure according to claim 14, wherein the groundwater drainage structure is embedded along the direction in which the underdrain extends, and is embedded so as to block groundwater. And underdrain line formed by lined several drainage structure of groundwater according to claim 14 or 15,
A drainage network for groundwater, comprising: a drainage trough interposed at a position to be inspected of the plurality of culvert drainage lines.

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