Water collection basin

Abstract

To provide a manhole facility to be installed underground and used as a facility for maintaining and managing underground buried facilities such as electricity, water supply and sewerage, and gas, and for branching the buried facilities, and as a tank for storing water, etc., which can be efficiently transported to the site during construction and repair work and can be easily constructed on site. [Solution] We provide a manhole facility to be installed underground, which is equipped with vertical panels that form the outer wall section and connectors that connect the left and right ends of the vertical panels and are positioned so that no tensile force is generated on the connecting surfaces.

Description

[Technical Field]

[0001] The present invention relates to a catch basin used for water supply and drainage, and a hand hole or manhole for managing underground buried objects. [Background technology]

[0002] For buried objects that are installed continuously underground, due to the nature of the buried objects and the need to branch out into branches, and for management purposes, box- or box-shaped structures installed underground are essential, and concrete structures are the mainstream for reasons of durability, etc.

[0003] To ensure quality and ease of construction, an in-situ concrete catch basin was invented using prefabricated formwork (JP 08-082095). However, in recent years, secondary products have been frequently used in the construction of concrete structures due to demands for high-quality, uniform output and a shortage of on-site engineers and highly skilled workers. When using secondary products on-site, there is a demand for reducing the cost of transporting them to the site and the burden on on-site workers.

[0004] One type of catchment box that is assembled on-site using secondary concrete products is one in which a lower box, a middle box, and an upper box are stacked vertically on-site (Jitsu Zen S58-029683). Another is one in which four crank-shaped side walls are joined in a Tomoe shape with metal fittings installed on the side wall surfaces (Jitsu Kokoku S61-130687). Another invention involves assembling a U-shaped subunit and an end wall subunit together (Patent Publication 2003-274546). All of these proposals have problems such as inefficient transportation and delivery, since the corners of the secondary products delivered to the site are manufactured in a factory.

[0005] A rainwater storage and infiltration facility assembled from plate-like members that are efficient to transport and install has a water channel member installed in the space secured by side plate members erected at intervals and multiple partition members installed between them (JP 2009-024453). To ensure water flow, this invention uses a structure in which the pressure of earth pressure on the side wall members is borne by the partition members, and the number of partition members varies depending on the magnitude of the earth pressure. Therefore, the partition members become an obstacle within the management space.

[0006] One invention for a prefabricated handhole involves stacking square cross-section members with staggered cutouts at the ends to secure space underground (JP Patent Publication No. 2001-211540). The structure is assembled using connecting holes that run vertically through the center of the cutouts at the ends, and connecting deformed reinforcing bars that run vertically between the connecting holes, but no consideration is given to the strength of the structure against earth pressure underground, and it was proposed as a structure for shallow underground use. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 08-082095 [Patent Document 2] Publication No. S58-029683 [Patent Document 3] Publication No. S61-130687 [Patent Document 4] Japanese Patent Application Laid-Open No. 2003-274546 [Patent Document 5] Japanese Patent Application Laid-Open No. 2009-024453 [Patent Document 5] Japanese Patent Application Laid-Open No. 2001-211540 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved is to propose a stable structure for box-shaped facilities such as underground collection basins and handholes, which are constructed by assembling and constructing basin facilities using components of the side walls of basin facilities that are secondary products of stable quality and are easy to assemble, install, transport, and carry in. [Means for solving the problem]

[0009] A cistern facility that is installed underground and has an outer wall that contacts the ground and an inner space, The outer wall portion is a vertical plate that is erected or stacked upward and connected to the left or right, with the ground side as the front face and the internal space side as the back face, and has left and right side faces and upper and lower faces; a connector for connecting the vertical panel to another vertical panel adjacent to the left or right, The vertical panel has a connecting surface with the adjacent other vertical panel on the back surface or the left or right side surface of the left or right end portion, The attachment surface on the back surface of the vertical panel is provided with a connector insertion portion that penetrates the vertical panel, or the attachment surface on the left or right side of the vertical panel is provided with a connector receiving portion that engages with an end of the connector that is inserted into the connector insertion portion of the adjacent other vertical panel, The connecting device is a manhole facility that can apply a compressive force to the outer wall portion so that no gaps are created at the attachment surface due to external forces from the ground side or the internal space side. [Effects of the Invention]

[0010] The present invention relates to vertical panels, which are plate-like bodies that form the outer walls of underground manhole facilities, and connectors that connect the vertical panels. Conventional manhole facilities made of precast products require large-scale transportation and installation. The manhole facility components of the present invention can be transported extremely efficiently, are easy to assemble and install on site, and can be installed according to the external conditions of the manhole facility. The main external forces that affect underground manhole facilities are earth pressure and groundwater pressure from the ground side on the outer wall, and water pressure from the interior space side, which are different from the direction of the manhole facility's own weight, which can be a major external force. Furthermore, external forces other than the manhole's own weight are often perpendicular to the wall surface of the structure in plan view, and are nearly uniformly distributed at the same height. Therefore, a relatively simple structure is sufficient for the vertical panels as structures that are subject to external forces. By using connectors to apply compressive force to the connecting surfaces, it is possible to prevent gaps between components caused by peeling stresses that occur due to external forces on the vertical panels of the outer wall. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram of an underground manhole facility (Example 1). [Figure 2] FIG. 2 is an explanatory diagram of a connector for an underground manhole facility (Example 1). [Figure 3] FIG. 3 is an explanatory diagram of the underground manhole facility (Example 2). [Figure 4] FIG. 4 is an explanatory diagram of a connector for an underground manhole facility (Example 3). DETAILED DESCRIPTION OF THE INVENTION

[0012] Underground manhole facilities are facilities for underground water supply and drainage facilities such as drainage facility catchments and water tanks, CAB facilities for telecommunications facilities, utility conduits including water supply and gas facilities, underground boxes for cable entry, branching, connection and management, and underground spaces for branching, connection and management of water pipes, gas pipes, etc. Each facility must be able to withstand external forces such as earth pressure and groundwater pressure that the facility is subjected to underground, but there may be differences in the tolerance for water leakage and the level of safety that must be ensured for the facility.

[0013] The vertical panel, which is a component of the underground manhole facility of this invention, is a plate-like body with a ground side and an internal space side, top and bottom surfaces, and left and right side faces, and is connected to other adjacent vertical panels on the left and right. Regarding the designation of the vertical panel, the outer ground side is the front, and the internal space side is the back. Regarding the left and right sides, the vertical panel has a connecting surface with the other adjacent vertical panel on the left, and is connected by a connector. Regarding the right side, the same relationship exists with the other adjacent vertical panels. Regarding the top and bottom, the top surface of the vertical panel may be provided with an anti-slip surface between it and the underside of the vertical panel it is placed on, but as long as the external force is evenly distributed and isodirectional, this is not essential for the structure and may be provided as a construction necessity. Furthermore, packing such as a seal may be used between adjacent vertical panels to prevent water leakage and intrusion.

[0014] The following equation 1 shows earth pressure as a typical external force that affects underground manhole facilities. The underground manhole facility in this example has five vertical tiers of panels connected vertically. Earth pressure is generated perpendicular to the front of the structure on all four sides, with magnitudes proportional to the height from the ground surface. This is shown in the cross-sectional diagram with dashed dotted lines. When the external forces are expressed in a plan view at the same height, as shown in the external force diagram (3), an evenly distributed load is applied from all four sides. The diagram used to calculate the earth pressure focuses on the lowest vertical tier of panels, with respect to earth pressure from the direction of the arrows.

[0015]

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[0016] An example of an underground manhole in the present invention is shown in the perspective view of equation 1 (1). An external force acting on this manhole is earth pressure, which is equal in magnitude to the horizontal plane as shown in the external force diagram of equation 1 (3), in a direction perpendicular to the outer wall. The cross section of the dot-dash line in the perspective view of equation 1 (2) shows the distribution of earth pressure in the vertical direction. The magnitude of the applied load is proportional to its depth, so overall, as shown in equation 1, P = 1 / 2 × γ × H 2 ×tan 2(45°-φ / 2), and the distributed load per unit length (unit height of the vertical panel in equation 1) is q = γ × H' × tan(45°-φ / 2). The elements of the equation are as shown in equation 1. If it is necessary to consider groundwater pressure, the external force can be found by adding it to the earth pressure. In this example, as shown in H', the external force per unit length is calculated by multiplying the earth pressure at the average height of one vertical panel by the height of the vertical panel, but in cases such as when the height of the vertical panel is large, it may be necessary to set a maximum external force. Next, we will explain the internal stresses in the components of the underground manhole facility that are generated by this external force. However, although vertical stress and shear force require separate consideration, their impact is relatively small and will not be discussed in this specification.

[0017]

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[0018] The change in shape and its cause when there are no connectors in response to the external force of Equation 1 are shown in Equation 2. Equation 2(1) shows the arrangement of the vertical panels and the relationship with the adjacent vertical panels on the left and right. The horizontal member 1 is arranged so that it sandwiches the vertical member 2, and the left and right back ends of the vertical panel of member 1 are attached to the right and left side faces of the vertical panel of member 2, forming four attachment surfaces for the entire box. When there are no connectors, the vertical panel will be warped towards the inner space as shown in the diagram of equation 2(2) due to the external force load of equation 1, and will open towards the front (ground side) at the connection surface as shown in the same diagram. The main cause of this is the bending moment that occurs in the member due to the action of the external force. The bending moment acting on the vertical panel is at its maximum at the center of each member, as shown in equations 2(4) and (5), and is M1=q×L1 2 / 8, M2=q×L2 2 This bending moment acts on the front side as a compressive force and on the back side as a tensile force, with the center line of the member cross section shown in Figure 2 (3) as the centerline. As a result, the deflection angle, which is the angle the member makes with respect to before the external force is applied, becomes maximum at the left and right ends of the vertical member, resulting in a gap opening up to the front side at the connecting surface.

[0019]

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[0020] The diagram in equation 3 shows the bending moment acting on the rigid members at the corners of a box structure with an internal space when subjected to the external force of equation 1. Equation (0) in equation 3 is the theoretical value of the bending moment when a rigid frame structure of members ABCD is subjected to an equal distributed load in the perpendicular direction from the outside, and was obtained from the literature shown in equation 3. The bending moment is positive when the direction in which tensile force occurs on the internal space side of the member. Furthermore, the lengths of the horizontal and vertical members are L1 and L2, and the second moments of area are I1 and I2. The corners are the areas surrounded by the solid and dashed lines at the four corners of the box structure in the diagram, and A OUT External forces also act from the outside of the corner, but their effect on the bending moment is small, so they are omitted. In order for members of a rigid frame structure to be stable against external forces, they need to be able to withstand negative bending moments that occur at each corner, as shown in the formula quoted from the literature (Equation 3). When the moment of inertia of the vertical and horizontal members is the same, that is, I1 = I2, M is A =M B =M C =M D =-q×L2 2 / 12×(1+(L1 / L2) 3 ) / (1+L1 / L2), and if we further set L2≧L1, then equation 3(2) holds, and M A =M B =M C =M D ≧-q×L2 2 / 12. Adding L2=L1 to the previous condition, M A =M B =M C =M D =-q×L2 2 / 12, which is the minimum value of the formula in equation 3(2). In this invention, the connector functions to prevent the occurrence of voids at the connecting surfaces of the vertical panels of the underground manhole facility. To prevent voids from occurring at the connecting surfaces of member 1 and member 2 in equation 2(2), the deflection angles at the left and right ends of member 1 and the angles at the left and right sides of member 2 are set to 0, and the connector ensures the strength against the bending moment generated at the corner obtained by equation 3, preventing the occurrence of voids between the members. When the vertical panels are made of concrete, the tensile stress caused by the bending moment generated at the midpoint of the member (position L1 / 2 for member 1, L2 / 2 for member 2) requires separate consideration of the placement of reinforcing bars, etc., but this consideration will be omitted in this specification.

[0021]

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[0022] The function of the connecting member consisting of a connecting tool and a connecting tool receiving part will be explained using equation 4. The connecting member is configured with a connecting tool receiving part that can tolerate the tensile force applied to the connecting tool, and the bending moment M shown in equation 4 (Fig. 2) is applied to the end of L1 of member 1. P This generates the bending moment M A That is, as shown in equation (1), M P ≦M A Therefore, the tensile force applied to the connector (which acts as a compressive force on member 1) is P ≥ q × L 2 On the other hand, the bending moment on the side of member 2 due to external force is M A This M A Stress σ inside member 2 caused by X As shown in Figure 4(1), at the position of X, σ X =M A / I2×X. This σ X The maximum value of (maximum tensile force) is σ at the position X=-T / 2 X=-T / 2 The compressive force σ acting on the contact surface due to the tensile force of the connector shown in Figure 4 (2) is PHowever, in order to prevent peeling stress from occurring, as shown in equation (2), P≧q×L 2 / (2×T). Here, the moment of inertia per unit length is I=T 3 As a result, the minimum required tensile force is P=q×L 2 In this case, as shown in the resultant force diagram of Figure 4 (3) within the dashed line in Equation 4, no tensile force acts on the front side with respect to the resultant force at the end of the member. Considering the influence of external forces on Member 1 and Member 2, comparing Equations 4 (1) and (2), the tensile force applied to the connector P≧q×L 2 / (2×T) is a necessary condition.

[0023] In equation 4, the connector is placed at the midpoint of the width T, which is the center of the attachment surface. However, the connector's placement position causes differences in the stress distribution on the attachment surface. Equation 5 shows the effect of the connector's placement position on the attachment surface. When a concentrated load acts on a flat plate placed on a flat surface, the reaction force from the plane below the plate is a linearly distributed load, with a maximum value being a and a minimum value being b. σ, the maximum peel stress generated on the front side of the attachment surface due to the external force obtained in equation 4 (1), is X=-T / 2 This is calculated assuming that a compressive force of a acts on the front end and a force of b acts on the back side as the compressive force on the attachment surface by the connector, an example of which is shown in Figure 4 (2).

[0024]

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[0025] Figure 1 in equation 5 shows the reaction force (assuming a linearly distributed load) from the plane to the underside of the plate when a concentrated load P is applied to a flat plate on a plane at an eccentricity distance ε towards the front side of the center. Equation 5 (0) holds due to the balance of forces, and equation 5 (0-1) holds due to the balance of moments. This clarifies the load distribution due to the eccentricity position ε. As shown in Figure 4 (2), when a load is applied to the center of the contact surface, the load is uniformly distributed, and Figure 5 (2) shows that ε = 0. The total load, which corresponds to the tensile force of the connector at this time, is P = P as shown in Equation 5 (3). C = a × T. Below we will show how the magnitude of the necessary concentrated load changes depending on the position of the concentrated load. In the case where the equation (5) in Figure 3 is placed at ε = -T / 6, the minimum load b is 0 with respect to the maximum load a. -T / 6 As shown in equation (4), P -T / 6 =P C / 2, achieving the objective at half the magnitude compared to when the load is applied at the center. Similarly, the case of ε = -T / 4 is shown in Figure 4 and Equation (5), and the case of ε = -T / 2 is shown in Figure 5 and Equation (6). When ε = -T / 4, it is 2 / 5, and when ε = -T / 2, it is 1 / 4. When connectors are placed in these positions where ε < -T / 6, it is necessary to consider that peeling stress acts on the back side when a tensile force is applied to the connector and no external force is yet acting from the ground. In other words, it is important to note that b in Figure 4 and Figure 5 is the peeling stress. [Example]

[0026] FIG. 1 is an explanatory diagram of an underground manhole facility 1 according to an embodiment of the present invention, having an internal space 21 that is approximately square in plan view and has two branches. FIG. 1(1) is a perspective view, and the elevation panels 3 designated a, b, c, d, and e shown in the perspective view are shown in FIGS. 1(2), 1(3), 1(4), 1(5), and 1(6), respectively. While FIG. 1(2) illustrates the top surface 32, front surface 31, and left and right side surfaces 34 and 33 of the elevation panels, the other FIGS. 1(3) through 1(6) illustrate the front, left side, and right side surfaces of the elevation panels. This underground manhole has the same elevation panel arrangement as in FIG. 2. The elevation panels b and d on the side with the branching section have connector insertion portions 36 at their left and right ends, allowing them to be connected and fixed to the adjacent elevation panels on the left and right. The elevation panel a connected to the left ends of the elevation panels b and d has connector receiving portions 37 at their left and right sides. In this example, the elevation plate opposite to the illustrated elevation plate has the same shape and is therefore not shown. The vertical panel can be a single piece that forms an exterior wall, as in a, or multiple panels can be stacked together, as in b, c, d, and e.

[0027] Fig. 2 shows the details of the connecting member of Example 1. Fig. 2(1) shows the state before the connection surface 35 on the back surface of the end of one vertical panel and the connection surface 35 on the side surface of the other adjacent vertical panel are connected. A bolt 41, which is a connector 4, is inserted into a connector insertion portion 36 on the left end of one vertical panel, and a washer 45 is placed on the seat. By tightening and rotating the head portion, the bolt 41 is combined with an embedded nut 44, which is a connector receiving portion 37 embedded in the right side surface of the other vertical panel, and a compressive force is applied to the two connection surfaces, fastening them together. Figure 2 (2) shows that an embedded bolt 43 is embedded in the right side of the other vertical plate as the connecting portion receiving portion, and is inserted into the connector insertion portion at the left end of one of the vertical plates. The nut 42 threaded into the tip of the threaded portion protruding from the front of the vertical plate is tightened and rotated, applying a compressive force to the two connecting surfaces, thereby fastening them together. As for the connection, as shown in Figure 1, there are cases where both the left and right sides are connected, such as vertical plates a, b, and d, and cases where only the left or right end is connected, such as vertical plates c and e adjacent to the left and right sides of a reinforced concrete rectangular culvert (hereinafter referred to as box culvert) 22 installed as a branch. In this case, one-sided fixation assuming a cantilever beam is required. One-sided fixation assuming a cantilever beam can be explained using equation 6.

[0028]

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[0029] Equation 6 shows the tensile force of the connector required when the vertical panels are connected on one side. The plan view of Equation 6 (1) shows two types of connection methods for two vertical panels sandwiching a box culvert. The connection shown in Equation 6 (3), the detailed view above, is the connection method for vertical panels c and e in Figure 1 of Example 1, and uses the back end of the vertical panel as the connecting surface. On the other hand, the connection shown in Equation 6 (4), the detailed view below Equation 6 (1), is a connection in which the side of the vertical panel is the connecting surface. Although the connecting method is different for each, in order to maintain the shape of the box, the crossing angle between the connecting plates must be kept at a right angle, and for this to happen, they must be in a cantilevered state as shown in Figure 6 (2). At the end, as shown in Equation 6 (0), M = q × L 2 In the case of the connection shown in Figure 6 (3), as shown in Equation 6 (1), P ≥ q × L 2 A connector with a tensile force of / T is required, but in the case of the connection shown in Figure 6 (4), P ≥ 3 × q × L 2 A connector of / T is required. Compared to Figure 6 (3), this connector has three times the strength, and in the case of one-sided connections, it shows that a connection with a contact surface at the rear end of the vertical panel as shown in Figure 6 (3) is advantageous. In addition, for the connected vertical panel of a cantilever type, the shape is assumed to be fixed due to the connection situation of the upper and lower vertical panels that sandwich the cantilever type. Regarding the strength of the connector, the tensile strength shown in Figure 4 is P ≥ q × L 2 Although this is a larger value than / (2×T), it should be noted that the length L of the vertical board is different. [Example]

[0030] Figure 3 shows an underground manhole facility 1 as an embodiment of the present invention, which has a roughly square interior space 21 with two branches of circular concrete pipes 23. The vertical panel 3 in this example has a connector insertion part on the left end and a connector receiving part on the right side, and the outer wall part 2 of the manhole facility has a Tomoe-shaped arrangement of vertical panels.

[0031] Figures 3(2) and (3) are exploded views of the masu facility in Figure 3(1). Each of the four vertical panels surrounding the roughly square internal space on a plane is composed of a single vertical panel. Figure 3(1) is a perspective view of the masu facility, and the constituent vertical panels 3 are marked with the symbols a and b. The components facing a and b are identical in shape and are omitted. Figure 3(2) shows the vertical panel a with the front view in the center and the left and right side views to the left and right. The rear view is a mirror image of the front view, and the plan view and bottom view have the same external shape and are both omitted. A row of multiple insertion holes, which are connector insertion sections 36, is arranged at the left end of the front side, and a row of multiple connector receiving sections 37 is embedded in the center of the right side. [Example]

[0032] In Examples 1 and 2, the connector insertion portion 36 of the vertical panel 3 was shown as an insertion hole, but FIG. 4 shows an example of a notched connector insertion portion 38. As explained using Equation 5, the effectiveness of the connector 4 varies depending on its installation position. In response to external forces from the ground, in order to deal with the peeling stress that generates a gap on the front side as shown in Equation 2, a vertical panel with an insertion portion cut out from the side can be aligned with the connector receiving portion 37 installed on the side of the adjacent vertical panel to be connected. Furthermore, in order for the compressive force acting between the two vertical panels due to the tensile force applied to the connector to act at the joining surface as expected by equation 5, the action of the compressive force must be distributed over the surface. To achieve this, it is expected that a load distribution plate 49 such as a flat washer with a large contact area as shown in Figure 4(2) will be used at the head of the fastening bolt, and a connector stress distribution allowance 48 as shown in Figure 4(1) will be provided at one of the receiving parts. [Example]

[0033] The following equation (7) explains the structural characteristics of an underground manhole when the external force from the inner space 21 is dominant. It is assumed that the water pressure in a tank such as an underground water tank exceeds the external force from the ground. Figure 7 (1) shows a schematic representation of the deformation of an underground manhole subjected to equal external forces from the internal space when there are no connectors. Opposite to the state shown in Figure 2, the backside of the four connecting surfaces deforms so that they open. In order to prevent deformation caused by the peeling stress of these connecting surfaces, the connectors required can be calculated by assuming that the bending moment generated at the corners of the rigid frame structure shown in Figure 3 is the action of a uniformly distributed load acting from the inside of the rigid frame structure (the internal space side of the manhole facility). Regarding the eccentric position of the connectors for effective use, they should be installed on the backside rather than the front side of the center line shown in Figure 5. Figure 7 (2) shows an example where the connector is installed +ε towards the backside from the installation center line. The connector stress distribution allowance is also installed on the backside.

[0034]

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[0035] 1 Underground manhole 2 outer wall section, 21 inner cavity section, 22 box culvert section, 23 circular pipe section 3 Elevation panel, 31 Front, 32 Top, 33 Right side, 34 Left side, 35 Mounting surface, 36 Connector insertion portion, 37 Connector receiving portion, 38 Notched connector insertion portion, 39 Elliptical connector insertion portion 4 Connector, 41 Bolt, 42 Nut, 43 Stud bolt, 44 Stud nut, 45 Washer, 46 Installation center line, 47 Eccentric distance, 48 Connector stress distribution allowance, 49 Load distribution plate

Claims

1. A cistern facility that is installed underground and has an outer wall that contacts the ground and an inner space, All of the side walls of the exterior wall section are erected or stacked upward, connected to the left or right, with the ground side as the front face and the internal space side as the back face, and have left and right side faces and upper and lower faces, and are vertical panels that can withstand external forces on the side walls with bending moments that are stresses inside the members of the side walls; a connector that connects the vertical panel to another vertical panel adjacent to the left or right and applies necessary stress to the corner portion inside the member of the connected vertical panel; The vertical panel has a connecting surface with the adjacent other vertical panel on the back surface or the left or right side surface of the left or right end portion, The attachment surface on the back surface of the vertical panel is provided with a connector insertion portion that penetrates the vertical panel, or the attachment surface on the left or right side of the vertical panel is provided with a connector receiving portion that engages with an end of the connector that is inserted into the connector insertion portion of the adjacent other vertical panel, The connector and the connecting receiving portion associated with the connector are positioned so that a compressive force can be applied to prevent gaps from forming across the entire attachment surface in response to deformation of the vertical panel due to stress acting on the interior of the vertical panel when external forces from the ground or internal space on the side wall apply to the panel, and the connector and connecting receiving portion associated with the connector are capable of holding a tensile force commensurate with the compressive force.

2. A manhole facility as claimed in claim 1, in which external forces from the ground side predominate and the attachment surface is the side surface of a vertical panel, is provided with the connector receiving portion on the front side, at a distance of at least 1 / 6 of the distance between the front and back of the vertical panel (hereinafter referred to as the width of the vertical panel) from the central plane between the front and back of the vertical panel (hereinafter also referred to as the center line in a plan view of the top surface of the vertical panel).

3. A manhole facility according to claim 1, in which external forces from the internal space side predominate and the attachment surface is the side surface of a vertical panel, is provided with the connector receiving portion on the back side of the vertical panel, at least 1 / 6 of the width of the vertical panel from the center line of the vertical panel in the plan view.

4. A manhole facility according to claim 1, wherein the vertical panel is made of concrete.

5. 2. A manhole facility, wherein the connector of claim 1 is a screw fastening member having a combination of male and female threads.

6. A vertical panel that is a component of the box facility of claim 1.

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