Methods for reinforcing existing underground structures

Abstract

This invention provides a method for reinforcing existing underground structures that facilitates construction. [Solution] The method for reinforcing an existing underground structure in this embodiment includes a cylindrical wall construction step in which joint portions 11 and 12 formed at both ends in the short direction of a side wall member 1 are connected to each other, and a cylindrical wall body 10 formed in a cylindrical shape by a plurality of side wall members 1 is constructed around the existing underground structure 8. The cylindrical wall construction step preferably includes a cylindrical wall erection step in which the side wall member 1 is held upright in relation to the ground, one joint portion 11 of the held side wall member 1 is connected to the other joint portion 12 of another side wall member 1 different from the side wall member 1, and the cylindrical wall body 10 is erected on the ground, and a casting step in which a plurality of side wall members 1 constituting the cylindrical wall body 10 are sequentially driven into the ground, and the cylindrical wall body 10 is installed around the existing underground structure 8.

Description

Technical Field

[0001] The present invention relates to a method for reinforcing existing underground structures.

Background Art

[0002] When constructing underground structures such as sump wells, deep foundation piles, underwater temporary cutoffs, and bridge piers, liner plates are mainly used as earth retaining structures. Since underground structures using liner plates are subject to deterioration such as corrosion over time, reinforcement or replacement of the underground structures becomes necessary. For example, as techniques for repairing sump wells using liner plates, the disclosed techniques of Patent Documents 1 and 2 are disclosed. There is.

[0003] The method for repairing a sump well in Patent Document 1 includes a step of attaching a connecting angle to an axial connecting flange that axially connects the liner plate located at least on one of the upper or lower sides of the corroded reinforcing ring, and a reinforcing step of attaching an inner winding ring to the inner peripheral side of the connecting angle.

[0004] The repair method for an existing sump pit in Patent Document 2 prepares a steel segment obtained by dividing a cylinder having an outer diameter slightly smaller than the inner wall of the existing sump pit after assembly into a plurality in the circumferential and axial directions, and a set member (positioning and supporting member) used when forming and installing the segment into a cylindrical unit. These members are formed into a cylindrical unit on the ground so that the set member is on the upper side, and are sequentially lifted and lowered to install and repair a steel plate cylinder.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The technology disclosed in Patent Document 1 involves attaching a connecting angle to the axial connecting flange of a liner plate and then attaching a reinforcing inner ring to the connecting angle. However, the axial connecting flange of the liner plate itself is often corroded. Therefore, there is a risk that construction using the inner ring may not be possible.

[0007] The technology disclosed in Patent Document 2 requires multiple steel segments, which divide the cylinder circumferentially and axially, as well as set members used when installing these cylindrical units, in order to construct a cylinder for reinforcing an existing water collection pit. As a result, there are problems with the large number of parts, which increases the time and effort required for manufacturing and construction.

[0008] Therefore, the present invention was devised in view of the above-mentioned problems, and its objective is to provide a method for reinforcing existing underground structures that can be easily constructed. [Means for solving the problem]

[0009] The method for reinforcing an existing underground structure according to the first invention is a method for reinforcing an existing underground structure, comprising a cylindrical wall construction step of connecting joint portions formed at both ends in the short direction of side wall members and constructing a cylindrical wall body formed by a plurality of side wall members around the existing underground structure, wherein the cylindrical wall construction step involves holding the side wall members upright relative to the ground, and connecting one joint portion of the held side wall member to another side wall member different from the said side wall member The method comprises: a cylindrical wall erection step of connecting the joint portion of one side and the other and erecting the cylindrical wall on the ground; and a driving step of sequentially driving the plurality of side wall members constituting the cylindrical wall into the ground and installing the cylindrical wall around the existing underground structure, wherein in the cylindrical wall erection step, the side wall members are driven in using a vibratory pile driver to bury the lower end of the side wall members in the ground, the vibratory pile driver is separated from the side wall members and the side wall members are held upright relative to the ground.

[0010] The method for reinforcing an existing underground structure according to the second invention is characterized in that, in the cylindrical wall erection step, a holding member is installed on the ground surface of the ground, the lower end of the side wall member is buried in the ground, and the side wall member is held upright relative to the ground by the holding member.

[0011] The method for reinforcing an existing underground structure according to the third invention is characterized in that, in the second invention, the holding member has a bottom plate portion and a guide member that rises from the bottom plate portion, and in the cylindrical wall erection step, the bottom plate portion is installed on the ground surface of the ground and the side wall member is held in place with respect to the ground by the guide member.

[0012] The method for reinforcing an existing underground structure according to the fourth invention is characterized in that, in the cylindrical wall erection step, a plate-shaped guide member having an opening is installed on the ground surface of the ground, and in the casting step, the outer surface of the side wall member is guided by the inner circumferential surface of the opening and the side wall member is cast into the ground.

[0013] The fifth invention relates to a method for reinforcing an existing underground structure, and comprises a cylindrical wall construction step of connecting joint portions formed at both ends in the short direction of side wall members and constructing a cylindrical wall body formed by a plurality of side wall members around the existing underground structure, wherein the cylindrical wall construction step involves holding the side wall members upright relative to the ground, and connecting one joint portion of the held side wall member to another side wall member different from the said side wall member. The method comprises: a cylindrical wall erection step of connecting the other joint and erecting the cylindrical wall on the ground; and a casting step of sequentially casting a plurality of the side wall members constituting the cylindrical wall into the ground and installing the cylindrical wall around the existing underground structure, wherein in the cylindrical wall erection step, a holding member is installed on the ground surface of the ground, the lower end of the side wall member is placed on the ground, and the side wall member placed on the ground is held upright relative to the ground by the holding member.

[0014] The method for reinforcing an existing underground structure according to the sixth invention is characterized in that, in the fifth invention, the holding member has a bottom plate portion and a guide member that rises from the bottom plate portion, and in the cylindrical wall erection step, the bottom plate portion is installed on the ground surface of the ground, and the side wall member is held to the ground by the guide member.

[0015] The method for reinforcing an existing underground structure according to the seventh invention is characterized in that, in the first or fifth invention, in the cylindrical wall erection step, a guide member is installed in the ground to serve as a guide when casting the side wall member, and in the casting step, the side wall member is cast while being guided by the guide member.

[0016] The method for reinforcing an existing underground structure according to the eighth invention is characterized in that, in the first or fifth invention, the casting step involves casting the side wall member and cutting the existing water collection pipe installed around the existing water collection well with the side wall member.

[0017] The method for reinforcing an existing underground structure according to the ninth invention is characterized in that, in the first or fifth invention, it further comprises an existing water collection pipe removal step of removing an existing water collection pipe installed around the existing water collection well, before the cylindrical wall construction step.

[0018] The method for reinforcing an existing underground structure according to the 10th invention is characterized in that, in the 1st invention or the 5th invention, it further comprises an existing drainage pipe removal step of removing existing drainage pipes installed around the existing water collection well before the cylindrical wall construction step.

[0019] The method for reinforcing an existing underground structure according to the 11th invention is characterized in that, in the first or fifth invention, it further comprises a water collection pipe installation step, after the cylindrical wall construction step, installing a water collection pipe that penetrates the cylindrical wall around the existing water collection well, and a drainage pipe installation step, after the cylindrical wall construction step, installing a drainage pipe that penetrates the cylindrical wall around the existing water collection well. [Effects of the Invention]

[0020] According to the first to eleventh inventions, a cylindrical wall body forming step is provided in which joints formed at both ends in the short direction of the side wall members are connected to construct a cylindrical wall body formed by a plurality of side wall members around an existing underground structure 8. Thereby, there is no need to attach a reinforcing member inside the existing underground structure as in the prior art. Further, since the joints of the side wall members can be connected to construct a cylindrical wall body, the number of members can be reduced compared to the prior art. Therefore, the construction can be easily performed.

[0021] Further, according to the first to eleventh inventions, since the existing underground structure is surrounded by the cylindrical wall body, the earth pressure and the like acting on the existing underground structure can be borne by the cylindrical wall body. Further, even when a lateral sway such as an earthquake acts, the bearing capacity and toughness of the underground structure can be improved by the restraining effect of the cylindrical wall body. Therefore, even when the existing underground structure is corroded, it is possible to reliably reinforce the existing underground structure.

[0022] According to the first to eleventh inventions, a cylindrical wall body erecting step is provided in which the side wall members are held in a state of standing upright with respect to the ground, and one joint of the held side wall member is connected to the other joint of another side wall member different from the side wall member to erect a cylindrical wall body formed by a plurality of side wall members on the ground. Thereby, even when the cylindrical wall body does not form a closed cross section in plan view due to an error in the arrangement position of the side wall members, a manufacturing error, or the like, the held side wall members can be aligned again to correct the cylindrical wall body to a closed cross section in plan view. As a result, the construction can be easily performed.

[0023] According to the first to eleventh inventions, in the cylindrical wall body erecting step, since the cylindrical wall body is erected on the ground, the formed shape of the cylindrical wall body can be confirmed in advance on the ground.

[0024] According to the first to eleventh inventions, a driving step is provided in which a plurality of side wall members constituting a cylindrical wall body are sequentially driven into the ground, and the cylindrical wall body is installed around an existing underground structure. Thereby, the side wall members can be quickly driven into the ground by a vibratory pile driver. For this reason, the work of manually connecting the liner plates as in the prior art can be omitted. Further, due to the driving by the vibratory pile driver, the load on the operator can be reduced, and labor saving can be achieved. For this reason, construction can be easily performed.

[0025] According to the first to eleventh inventions, after the step of erecting the cylindrical wall body, a driving step is provided in which a plurality of side wall members constituting the cylindrical wall body are sequentially driven into the ground, and the cylindrical wall body is installed around an existing underground structure. Thereby, when driving one side wall member, the one side wall member can be driven while sliding on the joints of the other side wall members arranged on both sides. For this reason, it is possible to reliably construct a cylindrical wall body of a predetermined shape in the ground.

[0026] In particular, according to the first to fourth inventions, in the step of erecting the cylindrical wall body, the lower end portion of the side wall member is buried in the ground and the side wall member is held in a standing state. Thereby, the standing state of the side wall member with respect to the ground can be stabilized. For this reason, even when the cylindrical wall body does not form a closed cross section in plan view due to an error in the arrangement position of the side wall member, a manufacturing error, etc., the side wall member can be pulled out from the ground, aligned again, and the cylindrical wall body can be corrected to a closed cross section in plan view. As a result, construction can be easily performed.

[0027] In particular, according to the seventh invention, in the step of erecting the cylindrical wall body, a guide member serving as a guide when driving the side wall member is installed on the ground, and in the driving step, the side wall member is guided by the guide member to drive the side wall member. Thereby, it becomes easy to drive the side wall member to a predetermined position. For this reason, the accuracy of the shape of the underground structure is improved.

[0028] In particular, according to the eighth invention, the existing underground structure is an existing water collection well, and the construction process involves casting side wall members and cutting the existing water collection pipes installed around the existing underground structure with the side wall members. This eliminates the need to remove the existing water collection pipes from underground. As a result, construction can be made even easier.

[0029] In particular, according to the ninth invention, the existing underground structure is an existing water collection well, and the invention further includes an existing water collection pipe removal step, in which the existing water collection pipes installed around the existing water collection well are removed before the cylindrical wall construction step. This allows the cylindrical wall to be constructed around the existing underground structure without being obstructed by the existing water collection pipes. Therefore, it becomes possible to reliably construct the cylindrical wall.

[0030] In particular, according to the tenth invention, the existing underground structure is an existing water collection well, and the invention includes an existing drainage pipe removal step in which the existing drainage pipes installed around the existing water collection well are removed before the cylindrical wall construction step. This allows the cylindrical wall to be constructed around the existing underground structure without being obstructed by the existing drainage pipes. Therefore, it becomes possible to reliably construct the cylindrical wall.

[0031] In particular, according to the 11th invention, the existing underground structure is an existing water collection well, and further comprises a water collection pipe installation step, which involves installing a water collection pipe that penetrates the cylindrical wall around the existing water collection well after the cylindrical wall construction step, and a drainage pipe installation step, which involves installing a drainage pipe that penetrates the cylindrical wall around the existing water collection well after the cylindrical wall construction step. This makes it possible to construct an underground structure as a water collection well. [Brief explanation of the drawing]

[0032] [Figure 1] Figure 1 is a partially broken front view showing an example of an underground structure in the first embodiment. [Figure 2] Figure 2 is a plan view showing an example of an underground structure in the first embodiment. [Figure 3] Figure 3 is a front view showing the process of removing existing drainage pipes, which is an example of a construction method for underground structures in the first embodiment. [Figure 4]Figure 4 is a front view showing the cylindrical wall erection process, which is an example of a construction method for underground structures in the first embodiment. [Figure 5] Figure 5 is a perspective view showing the cylindrical wall erection process, which is an example of a construction method for underground structures in the first embodiment. [Figure 6] Figure 6 is a front view showing the cylindrical wall erection process, which is an example of a construction method for underground structures in the first embodiment. [Figure 7] Figure 7 is a front view showing the pouring process of an example of a construction method for an underground structure in the first embodiment. [Figure 8] Figure 8 is a partially broken front view showing the casting process of an example of a construction method for an underground structure in the first embodiment. [Figure 9] Figure 9 is a partially cutaway front view showing the water collection pipe installation process and the drainage pipe installation process in an example of a construction method for an underground structure in the first embodiment. [Figure 10] Figure 10 is a side view showing the cylindrical wall erection process, which is an example of a construction method for underground structures in the second embodiment. [Figure 11] Figure 11 is a front view showing the pouring process of an example of a construction method for an underground structure in the third embodiment. [Figure 12] Figure 12 is a front view showing the pouring process of an example of a construction method for an underground structure in the third embodiment. [Figure 13] Figure 13 is a front view showing the process of removing existing water collection pipes and existing drainage pipes in an example of a construction method for underground structures in the fourth embodiment. [Figure 14] Figure 14 is a partially broken front view showing the cylindrical wall construction process, which is an example of a construction method for underground structures in the fifth embodiment. [Figure 15] Figure 15 is a partially broken front view showing the removal process of an existing underground structure, which is an example of a construction method for underground structures in the fifth embodiment. [Figure 16] Figure 16 is a partially broken front view showing the water collection pipe installation process and the drainage pipe installation process in an example of a construction method for an underground structure in the fifth embodiment. [Modes for carrying out the invention]

[0033] The following describes in detail, with reference to the drawings, the embodiments for implementing the reinforcement structure for existing underground structures, the reinforcement method for existing underground structures, and the construction method for underground structures to which the present invention is applied.

[0034] (First embodiment: underground structure 100, reinforcing structure 200 for existing underground structure) Figure 1 is a partially broken front view showing an example of an underground structure 100 according to the first embodiment. Figure 2 is a plan view showing an example of an underground structure 100 in the first embodiment.

[0035] The underground structure 100 comprises an existing underground structure 8 buried underground and a reinforcing structure 200 for the existing underground structure that reinforces the existing underground structure 8. The underground structure 100 is used, for example, as a water collection well. The underground structure 100 may also be used as a deep foundation pile, an underwater temporary cofferdam, a bridge pier, etc. Hereinafter, the reinforcing structure 200 for the existing underground structure will also be simply referred to as the reinforcing structure 200.

[0036] The existing underground structure 8 is used, for example, as a water collection well. The existing underground structure 8 is formed in a cylindrical shape by connecting multiple liner plates in the circumferential and vertical directions. The existing underground structure 8 is equipped with an existing water collection pipe 83.

[0037] The existing water collection pipe 83 is formed extending outward from the existing underground structure 8 and is buried underground. The existing water collection pipe 83 is a known piping material, such as a polyvinyl chloride pipe. The existing water collection pipe 83 is positioned to slope downward as it approaches the existing underground structure 8. The existing water collection pipe 83 is cut when the side wall member 1, which will be described later, is driven into place, thereby separating it into an inner and outer section of the cylindrical wall body 10.

[0038] The reinforcing structure 200 includes a cylindrical wall 10 that is buried underground. The reinforcing structure 200 may further include a water collection pipe 3 and a drainage pipe 4. The cylindrical wall 10 is constructed around the existing underground structure 8. Soil and sand are present between the cylindrical wall 10 and the existing underground structure 8.

[0039] The cylindrical wall 10 is formed in a cylindrical or other tubular shape by connecting a plurality of side wall members 1 in the circumferential direction. The cylindrical wall 10 is formed in a cylindrical shape by connecting the joint portions 11 and 12 of the side wall members 1, which are formed at both ends in the short direction, to each other.

[0040] The vertical length of the cylindrical wall 10 is longer than the vertical length of the existing underground structure 8. As a result, the lower end of the cylindrical wall 10 is positioned deeper than the lower end 8a of the existing underground structure 8. In this case, the cylindrical wall 10 is fixed in place so as to surround the entire height of the existing underground structure 8.

[0041] The side wall member 1 is, for example, a hat-shaped steel sheet pile. The side wall member 1 is formed in a rectangular shape when viewed from the front. The side wall member 1 has its longitudinal direction in the vertical direction, and joint portions 11 and 12 are formed at both ends in the short direction.

[0042] The side wall member 1 is preferably a steel sheet pile with a plate thickness of 10 mm or less. Furthermore, the side wall member 1 is preferably a stainless steel sheet pile.

[0043] The water collection pipe 3 is formed to extend outward from the existing underground structure 8 and is buried underground. The water collection pipe 3 is a known piping material, such as a polyvinyl chloride pipe. The water collection pipe 3 is positioned to slope downward as it approaches the existing underground structure 8. The water collection pipe 3 collects rainwater, groundwater, etc., from the ground outside the existing underground structure 8 and brings it to the inside of the existing underground structure 8. The water collection pipe 3 penetrates the cylindrical wall 10.

[0044] The drain pipe 4 is formed to extend outward from the existing underground structure 8 and is buried underground. The drain pipe 4 is installed at the lower end 8a of the existing underground structure 8. The drain pipe 4 is a known piping material, such as a steel pipe. The drain pipe 4 drains water collected inside the existing underground structure 8 to the outside of the existing underground structure 8. The drain pipe 4 penetrates the cylindrical wall 10.

[0045] (First embodiment: Method for reinforcing existing underground structures) Next, an example of a method for reinforcing an existing underground structure in the first embodiment will be described.

[0046] The method for reinforcing an existing underground structure is a method for reinforcing an existing underground structure 8, and comprises a step of constructing a cylindrical wall. The method for reinforcing an existing underground structure may further comprise a step of removing an existing water collection pipe, a step of removing an existing drainage pipe, a step of installing a water collection pipe, and a step of installing a drainage pipe.

[0047] <Existing drainage pipe removal process> As shown in Figure 3, the existing underground structure 8 is provided with an existing water collection pipe 83 and an existing drainage pipe 84. The existing drainage pipe 84 extends outward from the existing underground structure 8 and is buried underground. The existing drainage pipe 84 is installed at the lower end 8a of the existing underground structure 8. The existing drainage pipe 84 is a known piping material, such as a steel pipe. The existing drainage pipe 84 drains water collected inside the existing underground structure 8 to the outside of the existing underground structure 8.

[0048] The process of removing existing drainage pipes involves removing the existing drainage pipes 84 before the process of constructing the cylindrical wall.

[0049] In this embodiment, the existing water collection pipe 83 is left in place, but as in the embodiment described later, there may be an existing water collection pipe removal step in which the existing water collection pipe 83 is removed before the cylindrical wall construction step.

[0050] <Construction process for cylindrical wall> The cylindrical wall construction process involves connecting joints 11 and 12 formed at both ends in the short direction of rectangular side wall members 1, thereby constructing a cylindrical wall 10 formed by multiple side wall members 1 around the existing underground structure 8. The cylindrical wall construction process includes a cylindrical wall erection process and a concrete pouring process.

[0051] <<Cylindrical Wall Erection Process>> As shown in Figure 4, the cylindrical wall erection process involves placing a guide member 5 on the ground, which serves as a guide when the side wall member 1 is driven into the ground. The guide member 5 is made of steel plate and has an opening 51 formed in it. The guide member 5 is placed on the ground above the existing underground structure 8. The diameter of the opening 51 is larger than the diameter of the existing underground structure 8.

[0052] In the cylindrical wall erection process, as shown in Figures 5 and 6, the lower end 1a of the side wall member 1 is embedded using a vibratory pile driver suspended from a crane (not shown) while the outer surface of the side wall member 1 is in contact with the inner surface of the opening 51 of the guide member 5. The vibratory pile driver is then removed from the side wall member 1, and the side wall member 1 is held upright relative to the upper surface of the ground. At this time, the central part between the lower end 1a and the upper end 1b of the side wall member 1 is exposed above ground.

[0053] In the cylindrical wall erection process, the joint portion 11 of a side wall member 1, whose lower end 1a is embedded and held in the ground, is connected to the joint portion 12 of another side wall member 1 different from the said side wall member 1, and the lower end 1a of the other side wall member 1 is embedded and held in the ground. The holding of the side wall member 1 and the connection of the joint portion 11 of the held side wall member 1 to the joint portion 12 of the other side wall member 1 are repeated until a cylindrical wall 10, formed by multiple side wall members 1, is erected on the ground.

[0054] In this way, during the cylindrical wall erection process, a side wall member 1, with its longitudinal direction being vertical and joint portions 11 and 12 formed at both ends in the short direction, is held upright relative to the ground. One joint portion 11 of the held side wall member 1 is connected to the other joint portion 12 of another side wall member 1 that is different from the side wall member 1, thereby erecting a cylindrical wall 10 formed by multiple side wall members 1 on the ground. The cylindrical wall 10 is upright relative to the ground because the lower end portion 1a of the side wall member 1 is buried in the ground. The cylindrical wall 10 is erected on the ground above and outside the existing underground structure 8.

[0055] This allows the cylindrical wall body 10 to be corrected to a closed cross-section in plan view if the cylindrical wall body 10 does not have a closed cross-section in plan view due to errors in the placement of the side wall member 1, manufacturing errors, etc., by pulling out the held side wall member 1 and repositioning it.

[0056] <<Concrete casting process>> Next, in the driving process, as shown in Figures 7 and 8, a vibrating pile driver suspended from a crane (not shown) sequentially drives multiple side wall members 1 that make up the cylindrical wall 10 into the ground, thereby burying the cylindrical wall 10 in the ground.

[0057] As shown in Figure 7, the joint portion 11 of one side wall member 1 that is driven into the ground is connected to the joint portion 12 of another side wall member 1 adjacent to that side wall member 1. Similarly, the joint portion 12 of one side wall member 1 that is driven into the ground is connected to the joint portion 11 of another side wall member 1 adjacent to that side wall member 1. In other words, one side wall member 1 that is driven into the ground is embedded in the ground while sliding against the joint portions 11 and 12 of the other side wall members 1 on both sides. At this time, the central portion between the lower end portion 1a and the upper end portion 1b of the side wall member 1 is embedded in the ground. The upper end portion 1b of the side wall member 1 may be embedded in the ground or may be slightly exposed above ground.

[0058] In the casting process, the side wall member 1 is guided by the guide member 5 and cast into the ground. In the casting process, the side wall member 1 is cast while the outer surface of the side wall member 1 is in contact with the inner surface of the opening 51.

[0059] Then, as shown in Figure 8, in the casting process, all the side wall members 1 that make up the cylindrical wall 10 are buried in the ground. In the casting process, the cylindrical wall 10 is installed around the existing underground structure 8.

[0060] Furthermore, during the concrete casting process, the side wall member 1 is cast, and the existing water collection pipe 83, which is installed around the existing water collection well as an existing underground structure 8, is cut by the side wall member 1. As a result, the existing water collection pipe 83 is divided and positioned on the inside and outside of the side wall member 1.

[0061] In the concrete casting process, the cylindrical wall 10 is buried in the ground, and then the guide member 5 is removed.

[0062] <Water collection pipe installation process> Next, as shown in Figure 9, in the water collection pipe installation process, a water collection pipe 3 extending outward from the existing underground structure 8 is installed. In the water collection pipe installation process, holes are formed in the existing underground structure 8 and the ground by boring or the like, and the water collection pipe 3 is installed in the formed holes. In the water collection pipe installation process, a water collection pipe 3 is installed around the existing water collection well, penetrating the cylindrical wall 10.

[0063] <Drain pipe installation process> Next, in the drainage pipe installation process, a drainage pipe 4 extending outward from the cylindrical wall 10 is installed at the lower end 8a of the existing underground structure 8. In the drainage pipe installation process, holes are formed in the existing underground structure 8 and the ground by boring or the like, and the drainage pipe 4 is installed in the formed holes. In the drainage pipe installation process, a drainage pipe 4 that penetrates the cylindrical wall 10 is installed around the existing water collection well.

[0064] This concludes one example of a construction method for underground structures.

[0065] According to this embodiment, a cylindrical wall body 10 is constructed around an existing underground structure 8. The cylindrical wall body 10 is formed by connecting the joint portions 11 and 12 of side wall members 1, which have joint portions 11 and 12 formed at both ends in the short direction, and is formed into a cylindrical shape by multiple side wall members 1. This eliminates the need to attach reinforcing members to the inside of the existing underground structure, as in the conventional method. Furthermore, since the cylindrical wall body 10 can be constructed by connecting the joint portions 11 and 12 of the side wall members 1, the number of components can be reduced compared to the conventional method. This makes construction easier.

[0066] Furthermore, according to this embodiment, since the existing underground structure 8 is surrounded by the cylindrical wall 10, the earth pressure and other forces acting on the existing underground structure 8 can be borne by the cylindrical wall 10. In addition, even if lateral shaking such as earthquakes occurs, the restraining effect of the cylindrical wall 10 can improve the load-bearing capacity and toughness of the underground structure 100. For this reason, even if the existing underground structure 8 is corroded, it is possible to reliably reinforce the existing underground structure 8.

[0067] According to this embodiment, the method includes a cylindrical wall construction step in which joint portions 11 and 12 formed at both ends in the short direction of the side wall member 1 are connected to each other, and a cylindrical wall body 10 formed by multiple side wall members 1 is constructed around the existing underground structure 8. This eliminates the need to attach reinforcing members to the inside of the existing underground structure, as was done in the conventional method. Furthermore, since the cylindrical wall body 10 can be constructed by connecting the joint portions 11 and 12 of the side wall member 1, the number of components can be reduced compared to the conventional method. This makes construction easier.

[0068] According to this embodiment, the process includes a cylindrical wall erection step in which a side wall member 1 is held upright in relation to the ground, one joint portion 11 of the held side wall member 1 is connected to the other joint portion 12 of another side wall member 1 different from the said side wall member 1, and a cylindrical wall body 10 formed by a plurality of side wall members 1 is erected on the ground. As a result, even if the cylindrical wall body 10 does not have a closed cross-section in plan view due to errors in the placement position of the side wall members 1, manufacturing errors, etc., the held side wall member 1 can be repositioned and the cylindrical wall body 10 can be corrected to have a closed cross-section in plan view. As a result, construction can be made easier.

[0069] Furthermore, according to this embodiment, the cylindrical wall erection process involves erecting a cylindrical wall 10 on the ground, so the completed shape of the cylindrical wall 10 can be confirmed on the ground in advance.

[0070] Furthermore, according to this embodiment, the method includes a driving step in which a plurality of side wall members 1 constituting the cylindrical wall body 10 are sequentially driven into the ground, and the cylindrical wall body 10 is installed around the existing underground structure 8. This allows the side wall members 1 to be quickly driven into the ground using a vibratory pile driver. As a result, the work of manually connecting liner plates as in the conventional method can be omitted. In addition, because the driving is done using a vibratory pile driver, the burden on workers can be reduced, and labor can be saved. As a result, construction can be carried out easily.

[0071] Furthermore, according to this embodiment, both the crane and the vibratory pile driver are generally available, and construction can be carried out without the need for special equipment such as a silent piler. Therefore, there are fewer constraints during construction, and the versatility of construction can be improved.

[0072] Furthermore, according to this embodiment, after the cylindrical wall erection process, a casting process is included in which a plurality of side wall members 1 constituting the cylindrical wall 10 are sequentially cast into the ground to install the cylindrical wall 10 around the existing underground structure 8. This makes it possible to cast one side wall member 1 while sliding it against the joint portions 11 and 12 of the other side wall members 1 arranged on both sides. As a result, it becomes possible to reliably construct a cylindrical wall 10 of a predetermined shape in the ground.

[0073] According to this embodiment, the cylindrical wall erection process involves burying the lower end portion 1a of the side wall member 1 in the ground to hold the side wall member 1 in an upright position. This stabilizes the side wall member 1 in an upright position relative to the ground. Therefore, even if the cylindrical wall 10 does not have a closed cross-section in plan view due to errors in the placement of the side wall member 1, manufacturing errors, etc., the side wall member 1 can be pulled out of the ground, repositioned, and the cylindrical wall 10 can be corrected to have a closed cross-section in plan view. As a result, construction can be easily carried out.

[0074] According to this embodiment, in the cylindrical wall erection process, a guide member 5 is installed to serve as a guide when casting the side wall member 1, and in the casting process, the side wall member 1 is cast using the guide member 5 as a guide. This makes it easy to cast the side wall member 1 in a predetermined position. Therefore, the accuracy of the shape of the underground structure 100 is improved.

[0075] According to this embodiment, the existing underground structure 8 is an existing water collection well, and the construction process involves casting the side wall member 1 and cutting the existing water collection pipe 83 installed around the existing underground structure 8 with the side wall member 1. This eliminates the need to remove the existing water collection pipe 83 from underground. As a result, construction can be made even easier.

[0076] According to this embodiment, the existing underground structure 8 is an existing water collection well, and further comprises a water collection pipe installation step, which involves installing a water collection pipe 3 that penetrates the cylindrical wall 10 around the existing water collection well after the cylindrical wall construction step, and a drainage pipe installation step, which involves installing a drainage pipe 4 that penetrates the cylindrical wall 10 around the existing water collection well after the cylindrical wall construction step. This allows the underground structure 100 to be constructed as a water collection well.

[0077] According to this embodiment, the existing underground structure 8 is an existing water collection well, and the process includes an existing drainage pipe removal step in which the existing drainage pipe 84 installed around the existing water collection well is removed before the cylindrical wall construction step. This allows the cylindrical wall 10 to be constructed around the existing underground structure 8 without being obstructed by the existing drainage pipe 84. Therefore, it is possible to reliably construct the cylindrical wall 10.

[0078] According to this embodiment, the side wall member 1 is a steel sheet pile. By using a commonly available steel sheet pile, it is possible to construct the underground structure 100 with a member that has stable quality and cross-sectional performance.

[0079] According to this embodiment, the side wall member 1 is a lightweight steel sheet pile with a plate thickness of 10 mm or less. Compared to U-shaped steel sheet piles with a plate thickness exceeding 10 mm, lightweight steel sheet piles with a plate thickness of 10 mm or less have more clearance at the joint and a larger rotational angle at the joint. Therefore, when constructing the cylindrical wall body 10 which has a closed cross-section in plan view, it becomes easier to assemble. In addition, because the plate thickness of the side wall member 1 is thin, it is easier to drill holes in the cylindrical wall body 10 when boring the ground in the water collection pipe installation process and the drainage pipe installation process.

[0080] According to this embodiment, the side wall member 1 is a sheet pile made of stainless steel. This improves corrosion resistance and makes it possible to reduce the life cycle cost of the underground structure 100.

[0081] (Second embodiment: Method for reinforcing existing underground structures) Next, an example of a method for reinforcing existing underground structures in the second embodiment will be described. Detailed explanations of configurations similar to those in the first embodiment will be omitted below.

[0082] The method for reinforcing an existing underground structure is a method for reinforcing an existing underground structure 8, and comprises a cylindrical wall construction step. The cylindrical wall construction step comprises a cylindrical wall erection step and a concrete casting step.

[0083] <<Cylindrical Wall Erection Process>> The process of erecting the cylindrical wall body begins by placing a holding member 6 on the ground to maintain the upright position of the side wall member 1, as shown in Figure 10. The holding member 6 is formed, for example, in an L-shape in cross-section and has a bottom plate portion 61 that extends along the ground and a plate-shaped guide member 62 that rises from the bottom plate portion 61.

[0084] In the cylindrical wall erection process, a pair of holding members 6 are placed on the ground spaced apart from each other. Then, in the cylindrical wall erection process, a side wall member 1 is positioned between the pair of holding members 6, and the pair of holding members 6 holds the side wall member 1 upright relative to the ground. At this time, the lower end 1a of the side wall member 1 may be placed on the ground or buried in the ground. Also, the central part between the lower end 1a and the upper end 1b of the held side wall member 1 is exposed above ground.

[0085] Then, in the cylindrical wall erection process, the cylindrical wall 10 is erected on the ground using multiple side wall members 1.

[0086] <<Concrete casting process>> In the casting process, the side wall member 1 is guided by the guide member 62 of the holding member 6 and cast into the ground. In the casting process, the side wall member 1 is cast while the inner and outer surfaces of the side wall member 1 are in contact with the pair of guide members 62.

[0087] Then, during the concrete casting process, all the side wall members 1 that make up the cylindrical wall body 10 are buried in the ground. In the concrete casting process, the cylindrical wall 10 is buried in the ground, and then the retaining member 6 is removed.

[0088] Subsequently, similar to the first embodiment, the water collection pipe installation process and the drainage pipe installation process are carried out to complete one example of a method for reinforcing existing underground structures.

[0089] According to this embodiment, in the cylindrical wall erection process, the holding member 6 is installed in the ground, and the holding member 6 holds the side wall member 1 upright relative to the ground. This stabilizes the upright position of the side wall member 1. Therefore, even if the cylindrical wall 10 does not have a closed cross-section in plan view due to errors in the placement of the side wall member 1, manufacturing errors, etc., the held side wall member 1 can be removed from the holding member 6 and repositioned to correct the cylindrical wall 10 to have a closed cross-section in plan view. As a result, construction can be easily carried out.

[0090] According to this embodiment, in the cylindrical wall erection process, a pair of holding members 6 are installed spaced apart from each other, and the side wall member 1 is held upright relative to the ground by being sandwiched between the pair of holding members 6. This further stabilizes the upright position of the side wall member 1.

[0091] According to this embodiment, in the casting process, the side wall member 1 is cast while its inner and outer surfaces are in contact with a pair of guide members 62. This makes it even easier to cast the side wall member 1 in a predetermined position. As a result, the accuracy of the shape of the underground structure 100 is further improved.

[0092] (Third embodiment: Method for reinforcing existing underground structures) Next, an example of a method for reinforcing existing underground structures in the third embodiment will be described.

[0093] The method for reinforcing an existing underground structure is a method for reinforcing an existing underground structure 8, and includes a cylindrical wall construction step. The cylindrical wall construction step includes a cylindrical wall erection step and a concrete casting step. In the method for reinforcing an existing underground structure, the cylindrical wall erection step is performed in the same manner as in the first embodiment.

[0094] <<Concrete casting process>> In the driving process, as shown in Figure 11, after driving in one side wall member 1, a longitudinal joint side wall member 1' is placed above the first side wall member 1. The longitudinal joint side wall member 1' is the same as the side wall member 1. For example, a hat-shaped steel sheet pile is used for the longitudinal joint side wall member 1'. The longitudinal joint side wall member 1' is formed in a rectangular shape when viewed from the front. The longitudinal joint side wall member 1' has its longitudinal direction in the vertical direction, and joint portions 11' and 12' are formed at both ends in the short direction.

[0095] Then, in the driving process, as shown in Figure 12, the side wall member 1 and the longitudinally joining side wall member 1' are joined longitudinally by welding a backing plate 13 to them. In the driving process, after the side wall member 1 and the longitudinally joining side wall member 1' are joined longitudinally, the longitudinally joining side wall member 1' may be driven in using a vibratory pile driver if necessary.

[0096] According to this embodiment, in the concrete casting process, after casting one side wall member 1, a vertical joint side wall member 1' is vertically joined above the first side wall member 1. This ensures that the embedment length into the ground is secured by the vertical joint side wall member 1' when the length of the side wall member 1 is shorter than the design depth of the underground structure 100. Furthermore, the joint portions 11' and 12' of the vertical joint side wall member 1' can slide against the joint portions 11 and 12 of the other side wall members 1 adjacent to them on both sides. Therefore, the vertical joint side wall member 1' does not wobble when positioned above the side wall member 1, making it easy to align it with the lower side wall member 1 to which it is vertically joined.

[0097] (Fourth embodiment: Method for reinforcing existing underground structures) Next, an example of a method for reinforcing existing underground structures in the fourth embodiment will be described.

[0098] The method for reinforcing an existing underground structure is a method for reinforcing an existing underground structure 8, and comprises a step of constructing a cylindrical wall. The method for reinforcing an existing underground structure may further comprise a step of removing an existing water collection pipe, a step of removing an existing drainage pipe, a step of installing a water collection pipe, and a step of installing a drainage pipe.

[0099] <Removal process for existing water collection pipes> As shown in Figure 3, the existing underground structure 8 is equipped with an existing water collection pipe 83 and an existing drainage pipe 84.

[0100] As shown in Figure 13, the existing drainage pipe removal process involves removing the existing drainage pipe 83 before the cylindrical wall construction process. This allows the side wall members 1 to be cast without being obstructed by the existing drainage pipe 83 when constructing the cylindrical wall 10 around the existing underground structure 8.

[0101] Subsequently, similar to the first embodiment, the process of removing existing drainage pipes, constructing cylindrical walls, installing water collection pipes, and installing drainage pipes is carried out, completing one example of a method for reinforcing existing underground structures.

[0102] According to this embodiment, the process includes a step of removing existing drainage pipes 83 installed around the existing underground structure 8, prior to the construction of the cylindrical wall. This allows the cylindrical wall 10 to be constructed around the existing underground structure 8 without being obstructed by the existing drainage pipes 83. As a result, the cylindrical wall 10 can be reliably constructed.

[0103] (Fifth embodiment: Underground structure 100) Next, an example of the underground structure 100 in the fifth embodiment will be described.

[0104] As shown in Figure 16, the underground structure 100 includes a cylindrical wall 10 buried in the ground. The underground structure 100 may further include a beam 2, a water collection pipe 3, and a drainage pipe 4.

[0105] For example, an H-shaped steel beam may be used for beam member 2. Beam member 2 reinforces the cylindrical wall body 10 and is installed inside the cylindrical wall body 10. Beam member 2 is arranged along the inner circumferential surface of the cylindrical wall body 10. A rectangular steel pipe or the like may also be used for beam member 2.

[0106] The water collection pipe 3 is formed to extend outward from the cylindrical wall 10 and is buried underground. The water collection pipe 3 is a known piping material, such as a polyvinyl chloride pipe. The water collection pipe 3 is arranged to slope downward as it approaches the cylindrical wall 10. The water collection pipe 3 collects rainwater, groundwater, etc., from the ground outside the cylindrical wall 10 and brings it inside the cylindrical wall 10. Multiple water collection pipes 3 are arranged spaced apart in the vertical direction.

[0107] The drain pipe 4 is formed to extend outward from the cylindrical wall 10 and is buried underground. The drain pipe 4 is installed at the lower end of the cylindrical wall 10. The drain pipe 4 is a known piping material, such as a steel pipe. The drain pipe 4 drains the water collected inside the cylindrical wall 10 to the outside of the cylindrical wall 10.

[0108] (Fifth Embodiment: Construction Method for Underground Structures) Next, an example of a construction method for underground structures in the fifth embodiment will be described.

[0109] The construction method for the underground structure involves removing the existing underground structure 8 and installing a new underground structure 100. The construction method for the underground structure comprises a cylindrical wall construction step and an existing underground structure removal step. The construction method for the underground structure may further comprise an existing drainage pipe removal step, a water collection pipe installation step and a drainage pipe installation step.

[0110] <Existing drainage pipe removal process> The process for removing the existing drainage pipe is the same as in the first embodiment, in which the existing drainage pipe 84 is removed.

[0111] <Construction process for cylindrical wall> As shown in Figure 14, the cylindrical wall construction process is the same as in the first embodiment, in which joint portions 11 and 12 formed at both ends in the short direction of rectangular side wall members 1 are connected to each other, and a cylindrical wall 10 formed by multiple side wall members 1 is constructed around the existing underground structure 8.

[0112] <Process for removing existing underground structures> The existing underground structure removal process involves removing the existing underground structure 8 inside the cylindrical wall 10 and the soil inside the cylindrical wall 10. The existing underground structure removal process involves removing the existing water collection pipe 83 inside the cylindrical wall 10 and leaving the existing water collection pipe 83 outside the cylindrical wall 10 in the ground. The existing underground structure removal process includes a beam installation process.

[0113] <<Beam installation process>> As shown in Figure 15, the existing underground structure removal process includes a beam installation process in which beam members 2 are installed inside the cylindrical wall 10 after the existing underground structure 8 has been removed to a predetermined depth. This allows the cylindrical wall 10 to be reinforced. Alternatively, the existing underground structure removal process may include a beam installation process in which beam members 2 are installed inside the cylindrical wall 10 after all existing underground structures 8 have been removed.

[0114] <Water collection pipe installation process> As shown in Figure 16, the water collection pipe installation process involves installing the water collection pipe 3 extending outward from the cylindrical wall 10 after the existing underground structure 8 has been removed to a predetermined depth, or after the removal of the existing underground structure 8 has been completed. The water collection pipe installation process involves creating holes in the cylindrical wall 10 and the ground by boring or the like, and then installing the water collection pipe 3 into the created holes.

[0115] <Drain pipe installation process> The drainage pipe installation process includes installing drainage pipes 4 that extend outward from the cylindrical wall 10 around the lower end of the cylindrical wall 10 after the removal of the existing underground structure 8 has been completed. The drainage pipe installation process involves creating holes in the cylindrical wall 10 and the ground by boring or the like, and installing the drainage pipes 4 into the created holes.

[0116] This concludes one example of a construction method for underground structures.

[0117] According to this embodiment, the process includes a step for removing the existing underground structure 8 after the cylindrical wall construction step. As a result, when the existing underground structure 8 is removed, it is surrounded by the cylindrical wall 10, so the sides of the ground are not exposed, and ground collapse can be suppressed. Therefore, the existing underground structure 8 can be removed safely.

[0118] According to this embodiment, the existing underground structure removal process includes a beam installation process in which beam members 2 are installed inside the cylindrical wall 10 after the existing underground structure 8 has been removed to a predetermined depth. This allows for appropriate reinforcement of the cylindrical wall 10 by installing beam members 2 at predetermined positions within the cylindrical wall 10 while excavation is being carried out, thereby enabling safer construction.

[0119] According to this embodiment, the method includes a water collection pipe installation step of installing a water collection pipe 3 extending outward from the cylindrical wall 10 after the existing underground structure 8 has been removed to a predetermined depth, or after the removal of the existing underground structure 8 is completed, and a drainage pipe installation step of installing a drainage pipe 4 extending outward from the cylindrical wall 10 at the lower end of the cylindrical wall 10 after the removal of the existing underground structure 8 is completed. This makes it possible to construct the underground structure 100 as a water collection well.

[0120] In some of the embodiments described above, existing underground structures extending downward from the upper surface of the ground, such as water collection wells, were used as examples. However, existing underground structures may also be structures extending laterally from the side of the ground, such as tunnels or tunnel passages. In this case, the longitudinal direction of the side wall member 1 may be oriented laterally, and it may be cast into the ground against the side of the ground. The cylindrical wall body 10 will be constructed around existing underground structures such as tunnels or tunnel passages that extend laterally.

[0121] Although some embodiments of this invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. Furthermore, this invention can be implemented in various novel forms in addition to the embodiments described above. For example, in the embodiments described above, the cylindrical wall 10 is circular in plan view, but its shape is not limited to oval, horseshoe, rectangular, etc. Also, although the side wall member 1 is installed along the entire height of the existing underground structure 8, the side wall member 1 may be installed only below or above the existing underground structure 8. In this case, the cylindrical wall 10 is constructed to enclose a part of the existing underground structure 8. Therefore, the embodiments described above can be omitted, replaced, or modified in various ways without departing from the spirit of this invention. Such novel forms and modifications are included in the scope and spirit of this invention, as well as in the claims and equivalents of the claims. [Explanation of Symbols]

[0122] 100: Underground structure 200: Reinforcement structure 10: Cylindrical wall 1: Side wall member 1a: Bottom end 1b: Upper end 11: Joint section 12: Joint section 1': Side wall member for vertical joint 11': Joint section 12': Joint section 13: Backing plate 2: Beam material 3: Water collection pipe 4: Drain pipe 5: Guide member 51: Opening 6: Retaining member 61:Bottom plate part 62: Guide member 8: Existing underground structures 8a: Bottom end 83: Existing drainage pipe 84: Existing drainage pipes

Claims

1. A method for reinforcing existing underground structures, The process includes a cylindrical wall construction step in which joint portions formed at both ends in the short direction of side wall members are connected to form a cylindrical wall around the existing underground structure, and a cylindrical wall is formed by multiple side wall members. The aforementioned cylindrical wall construction step is: A cylindrical wall erection step is to hold the side wall member upright relative to the ground, connect one joint of the held side wall member to the other joint of another side wall member different from the said side wall member, and erect the cylindrical wall on the ground. The process includes a casting step of sequentially casting the multiple side wall members constituting the cylindrical wall into the ground and installing the cylindrical wall around the existing underground structure, In the process of erecting the cylindrical wall, The side wall member is driven into the ground using a vibratory pile driver, and the lower end of the side wall member is buried in the ground. The vibrating pile driver is separated from the side wall member, and the side wall member is held upright relative to the ground. A method for reinforcing existing underground structures characterized by the following.

2. In the process of erecting the cylindrical wall, The retaining member is installed on the ground surface of the ground, The lower end of the side wall member is buried in the ground, and the holding member holds the side wall member upright relative to the ground. A method for reinforcing an existing underground structure according to claim 1, characterized by the above.

3. The holding member has a bottom plate portion and a guide member that rises from the bottom plate portion. In the process of erecting the cylindrical wall, the bottom plate is placed on the ground surface, and the side wall members are held in place by the guide members. A method for reinforcing an existing underground structure according to claim 2, characterized by the above.

4. In the process of erecting the cylindrical wall, a plate-shaped guide member having an opening is installed on the ground surface. In the casting process, the outer surface of the side wall member is guided by the inner circumferential surface of the opening to cast the side wall member. A method for reinforcing an existing underground structure according to claim 1, characterized by the above.

5. A method for reinforcing existing underground structures, The process includes a cylindrical wall construction step in which joint portions formed at both ends in the short direction of side wall members are connected to form a cylindrical wall around the existing underground structure, and a cylindrical wall is formed by multiple side wall members. The aforementioned cylindrical wall construction step is: A cylindrical wall erection step is to hold the side wall member upright relative to the ground, connect one joint of the held side wall member to the other joint of another side wall member different from the said side wall member, and erect the cylindrical wall on the ground. The process includes a casting step of sequentially casting the multiple side wall members constituting the cylindrical wall into the ground and installing the cylindrical wall around the existing underground structure, In the process of erecting the cylindrical wall, A retaining member is installed on the ground surface of the ground, the lower end of the side wall member is placed on the ground, and the side wall member placed on the ground is held upright relative to the ground by the retaining member. A method for reinforcing existing underground structures characterized by the following.

6. The holding member has a bottom plate portion and a guide member that rises from the bottom plate portion. In the process of erecting the cylindrical wall, the bottom plate is placed on the ground surface, and the side wall members are held in place by the guide members. A method for reinforcing an existing underground structure according to claim 5, characterized by the above.

7. In the process of erecting the cylindrical wall, a guide member is installed in the ground to serve as a guide when the side wall member is cast into place. In the casting process, the side wall member is guided by the guide member and cast. A method for reinforcing an existing underground structure according to claim 1 or 5, characterized by the above.

8. The aforementioned casting process involves casting the side wall member and cutting the existing water collection pipe installed around the existing water collection well with the side wall member. A method for reinforcing an existing underground structure according to claim 1 or 5, characterized by the above.

9. Prior to the cylindrical wall construction step, the process further includes removing existing water collection pipes installed around the existing water collection well. A method for reinforcing an existing underground structure according to claim 1 or 5, characterized by the above.

10. Prior to the cylindrical wall construction step, the process further includes removing existing drainage pipes installed around the existing water collection well. A method for reinforcing an existing underground structure according to claim 1 or 5, characterized by the above.

11. Following the cylindrical wall construction step, a water collection pipe installation step is performed in which a water collection pipe is installed around the existing water collection well, penetrating the cylindrical wall. Following the cylindrical wall construction step, a drainage pipe installation step is performed in which a drainage pipe is installed around the existing water collection well, penetrating the cylindrical wall. To further enhance A method for reinforcing an existing underground structure according to claim 1 or 5, characterized by the above.

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