JP7439588B2 - Shoring structure of retaining wall - Google Patents

Description

The present invention relates to a shoring structure for a retaining wall used when excavating the ground.

BACKGROUND ART Conventionally, when excavating a construction target area, a mountain retaining work has been employed in which a retaining wall is installed to prevent the collapse of the ground. For example, Patent Document 1 discloses various methods of performing excavation work on a slope using a retaining wall in the prior art.

Specifically, when one side of a horizontal strut is located on the mountain side and the other side is located on the valley side, the area near the top of the mountain side wall and the valley side wall An additional diagonal strut will be installed between the upper end and the upper end. Alternatively, instead of the struts, provide a ground anchor on the back side of the retaining wall to support the retaining wall. Alternatively, a foundation or sacrificial concrete is constructed within the construction target area surrounded by the retaining wall, and a strut is installed between the foundation or the sacrificial concrete and the vicinity of the upper end of the retaining wall on the mountain side.

The method of installing an additional diagonal beam between the mountain retaining wall on the mountain side and the mountain retaining wall on the valley side assumes that if the lateral pressure acting on the mountain retaining wall on the mountain side is excessive, it may not be supported by the mountain retaining wall on the valley side. . Furthermore, the method of providing ground anchors cannot be adopted if sufficient land cannot be secured to provide ground anchors on the back side of the retaining wall. Furthermore, the method of constructing a foundation or concrete in a construction target area surrounded by retaining walls is unstable and unreliable as a support structure for the lateral pressure acting on retaining walls on the mountain side.

For this reason, in Patent Document 1, support piles reaching up to the support layer are provided in the construction target area surrounded by the mountain retaining wall, and a foundation is provided at the head of this support layer, and this foundation and the vicinity of the mountain retaining wall on the mountain side are provided. A strut is installed between the two. In addition, ground anchors are installed at the foundation to ensure stability as a support structure for the lateral pressure acting on the retaining walls on the mountain side.

Japanese Patent Application Publication No. 07-252835

According to the method of Patent Document 1, it is possible to secure a large bearing capacity using ground anchors for the foundation where the diagonal strut is installed, so even when a large lateral pressure acts on the mountain retaining wall on the mountain side, the retaining wall on the mountain side can be stably supported. However, such foundations and diagonal struts are not only complicated to construct, but may also interfere with excavation work and frame construction work performed in the construction target area surrounded by retaining walls. Further, if the displacement of the retaining wall becomes excessive before the construction of the foundation is completed, no effect will be obtained, so the larger the excavation depth, the more difficult it is to apply.

Under these circumstances, instead of taking countermeasures by shoring the mountain retaining wall, it is possible to consider methods such as increasing the rigidity of the entire mountain retaining wall that surrounds the construction target area, or increasing the rigidity of the mountain retaining wall itself on the mountain side, but the construction cost is low. And it is likely to be disadvantageous in terms of construction period.

The present invention was made in view of this problem, and its main purpose is to provide a shoring structure for a retaining wall that can realize a rational retaining plan.

In order to achieve this object, the shoring structure for a mountain-retaining wall of the present invention is a shoring structure for a mountain-retaining wall installed in the ground, and includes flints provided at the corner portions of adjacent raised sides, and a support structure for a mountain-retaining wall installed underground. A first telescopic device interposed in at least one of the uprights, and a contact portion where the adjacent said uprights come into contact with each other, the first telescopic device and the contact portion In between, a connection position of the flint with respect to the hoist is arranged , and a connection position of the strut is arranged on the opposite side of the connection position of the flint with the first expansion/contraction device of the hoop up in between. It is characterized by being

According to the shoring structure for a retaining wall of the present invention, flints are provided in the corner portions of adjacent uprights, and the first expansion and contraction device is interposed in one of the adjacent uprights, and an additional shaft is provided. Force can be applied.

As a result, the lateral pressure acting on the retaining wall on which the other raised wall was installed was transferred to one raised wall and the flint, which were interposed with the first expansion and contraction device. It can be transmitted to the mountain retaining wall as an in-plane force, and the mountain retaining wall to which the in-plane force is transmitted resists this with the frictional force generated between it and the ground.

Therefore, when lateral pressures of different magnitudes act on each of the facing retaining walls, the first expansion and contraction device is interposed in the uprights of the retaining walls arranged to connect these walls, and the adjacent retaining walls are By providing flint at the corner of the wall, the retaining wall can be reinforced without the need for large-scale shoring, making it possible to design and construct a retaining wall in a rational and economical manner.

Moreover, the shoring structure for a retaining wall of the present invention is characterized in that a second expansion and contraction device is interposed in the flint.

According to the shoring structure for a retaining wall of the present invention, additional axial force is applied to the flints that support the retaining wall through the uprights through the second expansion and contraction device, so the shoring structure supports the retaining wall. This increases the rigidity of the retaining wall, making it possible to more reliably suppress deformation of the retaining wall.

In addition, in the shoring structure for a mountain retaining wall of the present invention, a locking member that locks to the ground is provided on the mountain retaining wall provided with the raised side with the first expansion and contraction device interposed therebetween. Features.

According to the shoring structure of the mountain retaining wall of the present invention, the mountain retaining wall to which the in-plane force is transmitted through one of the uprights and the flints with the first expansion/contraction device interposed therebetween is able to maintain the rigidity of the mountain retaining wall itself and the ground. In addition to the frictional force with the mountain, this in-plane force can be resisted by the resistance force of the locking member against the ground. Thereby, even if the lateral pressure transmitted as an in-plane force is excessive, it is possible to reliably prevent deformation of the mountain retaining wall that receives this lateral pressure from the ground.

According to the present invention, flints are provided in the inner corners of adjacent ribs, and the first expansion and contraction device is interposed in one of the adjacent ribs, so that additional axial force can be applied. , the lateral pressure acting on the retaining wall provided with the other raised part is applied to the retaining wall provided with the raised part of the other side through one raised part and the flint interposed with the first expansion/contraction device. Since it can be transmitted as an in-plane force to the surface, it becomes possible to design and construct a rational and economical retaining wall without employing large-scale shoring.

FIG. 2 is a diagram showing a cross section of a construction target area surrounded by retaining walls in an embodiment of the present invention. FIG. 3 is a diagram showing a plane of a construction target area surrounded by retaining walls in an embodiment of the present invention. It is a figure which shows the 2nd expansion-contraction device provided in the flint in embodiment of this invention. It is a figure showing details of the shoring structure of the retaining wall in an embodiment of the present invention. It is a figure which shows the other example of the shoring structure of the retaining wall in embodiment of this invention. It is a figure (1) which shows various conditions for analyzing the displacement state which arises in the retaining wall in embodiment of this invention. It is a figure which shows various conditions for analyzing the displacement state which arises in the retaining wall in embodiment of this invention (Part 2). It is a figure which shows the displacement state which occurs in the retaining wall in embodiment of this invention. It is a figure which shows the locking member provided in the mountain retaining wall in embodiment of this invention.

The present invention is suitable for mountain retaining work when uniform lateral pressure does not act on the retaining wall surrounding the construction target area, such as when the target construction area exists on a slope or when excavating the target construction area on one side. This is the shoring structure of the retaining wall used.

In this embodiment, a case where the construction target area exists on a slope will be taken as an example, and the details will be explained below with reference to FIGS. 1 to 9.

As shown in the cross-sectional view of FIG. 1 and the plan view of FIG. 2, a construction target area 10 located on a slope is surrounded by a retaining wall 1. The retaining wall 1 is a column-type soil cement wall constructed by the SMW construction method, and in this embodiment, core materials 11 are penetrated into the soil cement wall at a predetermined pitch.

Of the mountain retaining walls 1 surrounding these construction target areas 10, the north retaining wall 1N located on the north side and the south retaining wall 1S opposite thereto have lateral pressure (groundwater pressure and (including earth pressure).

On the other hand, a larger lateral pressure acts on the east side retaining wall 1E located on the east side than the lateral pressure acting from the ground on the west side retaining wall 1W facing the east side retaining wall 1E. These four retaining walls 1E, 1W, 1N, and 1S are reinforced by a shoring structure 2 provided on the construction target area 10 side.

The shoring structure 2 includes an east side upright 3E, a west side upright 3W, a south side upright 3S, and a north side upright provided on each of the east side retaining wall 1E, the west side retaining wall 1W, the south side retaining wall 1S, and the north side retaining wall 1S. It is provided with a raiser 3N, a flint 4, a strut 5, a strut flint 6, a first expansion and contraction device 7, and a second expansion and contraction device 7'.

To explain these arrangements for each of the three sections (west area 10a, central area 10b, and east area 10c) that divide the construction target area 10 in the east-west direction, first, in the west area 10a of the construction target area 10, multiple Flints 4 are provided in the vicinity of the inner corner part A of the west side riser 3w and the north side riser 3N, and in the vicinity of the inner corner part A of the west side riser 3w and the south side riser 3S, respectively.

Further, in the central area 10b of the construction target area 10, the struts 5 are arranged in the north-south direction so as to connect the central parts of the north side riser 3N and the south side riser 3S. Further, each of the north side riser 3N and the south side riser 3S transmits the load to the strut 5 not only from the connection portion with the strut 5 but also via the strut flint 6.

In the east area 10c of the construction target area 10, a plurality of flints 4 are located near the corner portions A of the east side upright 3E, the north side upright 3N, and the east side upright 3E and the south side upright 3S. However, in addition to these, a first telescopic device 7 is interposed in the north side riser 3N and the south side riser 3S, and a second extendable device 7' is interposed in each of the plurality of flints 4. equipped.

As shown in FIG. 3(a), the second telescoping device 7' provided on the flint 4 can be any of the Kirin jacks, universal jacks, or preload jacks that have been commonly used in the preload construction method of the struts 5. A jack can also be used. These second expansion and contraction devices 7' are interposed in the middle part of the flint 4, and expand and contract in the axial direction of the flint. At this time, as required, as shown in FIG. 3(b), the jack cover 8 is attached so as to straddle the flints 4 located on both sides of the second telescoping device 7'.

Note that the first telescopic device 7 used for the north side upright 3N and the south side upright 3S also has the same configuration as the second expandable device 7'. In addition, when the first expansion and contraction device 7 is provided on the north side riser 3N and the south side riser 3S, as shown in FIG. 31 and the first telescopic device 7.

As described above, in the east area 10c of the construction target area 10, the same flints 4 as in the west area 10a are used, and the second expansion and contraction device 7' is interposed in these flints 4. Further, a first expansion/contraction device 7 is installed in each of the north side riser 3N and the south side riser 3S. Thereby, deformation of the east retaining wall 1E due to lateral pressure can be suppressed.

That is, in the east area 10c, as shown in FIG. 4, the lateral pressure acting near the end of the east side retaining wall 1E acts in the axial direction of the north side riser 3N via the east side riser 3E. Further, a component of the lateral pressure acting near the intermediate portion of the east retaining wall 1E acts in the axial direction of the flint 4 via the east side upright 3E. Although not shown, similar force transmission is performed in the south side riser 3S as well.

However, an additional axial force corresponding to this lateral pressure acting in the axial direction is applied to the north side riser 3N by extending the first expansion/contraction device 7. Similarly, an additional axial force corresponding to the component force of the lateral pressure is applied to the flint 4 by extending the second telescoping device 7'.

Thereby, the side pressure acting on the east side retaining wall 1E is transmitted as an in-plane force Pm of the north side retaining wall 1N via the flint 4 on which additional axial force acts and the north side upright 3N. Then, the north retaining wall 1N resists this in-plane force Pm due to the frictional force F generated between it and the ground. Although not shown, the in-plane force Pm is similarly transmitted to the south side upright 3S, but the south side retaining wall 1S also resists this due to the frictional force F generated between it and the ground. At this time, the rigidity of the flint 4, the north side upright 3N, and the south side upright 3S, on which additional axial force acts, and the in-plane rigidity of the north side retaining wall 1N and the south side retaining wall 1S are exerted, and the lateral pressure of the east side retaining wall 1E is exerted. deformation caused by this is suppressed.

Therefore, even when the lateral pressure acting on the east side retaining wall 1E is greater than the lateral pressure acting on the west side retaining wall 1W, the second expansion and contraction device 7' is provided in the flint 4, and the north side upright 3N and the south side upright 3S By providing a first expansion/contraction device 7 in the area and applying additional axial force to each, deformation of the east retaining wall 1E can be suppressed by shoring using flint 4 made of the same material as in the west area 10a. can.

In this way, there is no need to provide large-scale supports such as diagonal struts or ground anchors in order to cope with the excessive lateral pressure acting on the east retaining wall 1E. In contrast, rational and economical design and construction are possible.

In this embodiment, since the construction target area 10 is provided on a slope, as the excavation work in the construction target area 10 progresses, different magnitudes of lateral pressure act on the opposing east side retaining wall 1E and west side retaining wall 1W. I gave an example of a case where However, even when the excavation procedure in the construction target area 10 causes a difference in the lateral pressure acting between the east side retaining wall 1E and the west side retaining wall 1W, the shoring structure 2 of the retaining wall 1 can be adopted.

Specifically, as shown in FIG. 5(a), at the beginning of construction, almost the same lateral pressure is applied to the east side retaining wall 1E and the west side retaining wall 1W, but within the construction target area 10, For example, when digging by so-called one-sided excavation, such as excavating from the east side to the west side, the lateral pressure acting on the east side retaining wall 1E becomes larger than the lateral pressure acting on the west side retaining wall 1W.

Therefore, at the beginning of construction, the first telescoping device 7 and the second telescoping device 7' are only installed, but they are not expanded, and the first telescoping device 7 and the second telescoping device 7 are installed as appropriate according to the progress of the excavation work. Stretch '. In this way, an additional axial force corresponding to the lateral pressure acting on the east retaining wall 1E, which changes depending on the progress of the excavation work, is applied to the north side upright 3N, south side upright 3S, and flint 4 as appropriate. be able to. Note that the first expansion and contraction device 7 and the second expansion and contraction device 7' are not limited to this, and may be expanded as appropriate depending on the site situation.

In addition, the shoring structure 2 of the retaining wall 1 can be installed in any of the east side uprights 3E, west side uprights 3W, south side uprights 3S, and north side uprights 3N as needed. A first telescoping device 7 may also be provided. On the other hand, the flint 4 does not necessarily need to be provided with the second telescoping device 7'.

For example, as shown in FIG. 5(b), the total length (length seen from the plane) of the east retaining wall 1E, on which large lateral pressure acts, is short, and it If the deformation of the east retaining wall 1E can be suppressed by applying additional axial force, the second expansion and contraction device 7' may not necessarily be provided on the flint 4. In this case, it is preferable to provide the first expansion and contraction device 7 also on the east side riser 3 on which the lateral pressure acts.

Regarding the shoring structure 2 of the retaining wall 1 having the above configuration, the results of estimating the displacement state occurring in the east retaining wall 1E and the west retaining wall 1W by three-dimensional FEM analysis are shown below.

In this analysis, as shown in the analytical model of FIG. 6(a), the total length of the mountain retaining wall 1 surrounding the construction target area 10 is 36 m, the total length of the south mountain retaining wall 1S and the north mountain retaining wall 1N, the east mountain retaining wall 1E, and the west mountain retaining wall. The total length of 1W was set as a rectangle in plan view of 18 m. Furthermore, the lower ends of these were all assumed to reach a depth of 15 m, and the ground was set to be sandy soil with a unit pile weight of 17 kN/m ³ , a cohesive force of 0 kN/m ³ , and an internal friction angle of 35°.

Furthermore, as shown in FIGS. 6(b) and 6(c), the retaining wall 1 has a core material 11 made of H-beam steel in the soil cement wall constructed by the SMW construction method as shown in FIGS. 1 and 2. The length of the core material 11 was set to 12 m.

Under the above conditions, the shoring structure 2 was provided at a height of 3 m in the construction target area 10, as shown in FIG. Then, the lateral pressure acting on the east side retaining wall 1E is set to be greater than the lateral pressure acting on the west side retaining wall 1W, and the east side retaining wall is The amount of displacement of the wall 1E and the west retaining wall 1W was estimated.

In addition, the above analysis is performed not only for the case where additional axial force is applied to each of the north side upright 3N, south side upright 3S, and flint 4, but also for the case where no additional axial force is applied as a comparative example. I did it.

FIG. 8 shows the amount of displacement in the depth direction of the west side retaining wall 1W and the east side retaining wall 1E at the time when the secondary excavation is completed. Looking at Figure 8, for the east retaining wall 1E to which a large lateral pressure was applied, the displacement at the depth at which the shoring was installed was approximately 5 mm, and the maximum displacement at the total depth was approximately 5 mm with and without the introduction of additional axial force. There is a difference of about 2 mm. From this, the effect of providing the first expansion and contraction device 7 on the north side upright 3N and the south side upright 3S, and providing the second expansion and contraction device 7' on the flint 4 to apply additional axial force. can be seen.

On the other hand, looking at the amount of displacement of the west retaining wall 1W, it can be seen that there is no difference in the amount of displacement between when the additional axial force is applied and when it is not applied. This is because the north side retaining wall 1N and the south retaining wall 1S, to which the lateral pressure acting on the east retaining wall 1E is transmitted as an in-plane force Pm, resist and cancel out this in-plane force Pm due to the frictional force F generated between them and the ground. However, it can be presumed that the lateral pressure of the east retaining wall 1E was not transmitted to the west retaining wall 1W.

Note that the retaining wall 1 according to the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention.

For example, in this embodiment, a soil cement wall constructed by the SMW construction method is used as the retaining wall 1, but the present invention is not limited to this. When the retaining wall 1, such as a soil cement wall constructed by other construction methods or an underground wall made of reinforced concrete, moves against the ground, it resists on the surface in contact with the ground, resulting in a frictional force F. Any method may be adopted as long as it produces the following.

Further, the north side mountain retaining wall 1N and the south side mountain retaining wall 1S, on which the belly riser 3 interposed with the first expansion/contraction device 7 is provided, may be provided with a locking member 9 on the wall surface on the ground side. Specifically, as the locking member 9, as shown in FIG. 9(a), a ground improvement body is provided so as to protrude toward the ground from the back surface of the north mountain retaining wall 1N. Alternatively, as shown in FIG. 9(b), a steel material such as an H-shaped steel is provided so as to protrude toward the ground from the back surface of the north mountain retaining wall 1N.

In this way, even when the lateral pressure acting on the east side retaining wall 1E is excessive, or when the frictional resistance generated between the north side retaining wall 1N and the ground is insufficient due to ground conditions, the lateral pressure acting on the east side retaining wall 1E can be reduced to the surface. The north mountain retaining wall 1N, which is transmitted as an internal force Pm, can resist this in-plane force Pm by the frictional force F generated between it and the ground, as well as the resistance force R' exerted between the locking member 9 and the ground. . Although not shown, a similar locking member 9 is also provided on the south retaining wall 1S to transmit the same force.

As a result, even if the lateral pressure acting in the axial direction of the north side upright 3N and the south side upright 3S, in which the first expansion and contraction device 7 is installed, is excessive, the east side mountain retainer receives this lateral pressure from the ground. It becomes possible to reliably prevent deformation of the wall 1E.

1 Mountain retaining wall 1E East side mountain retaining wall 1W West side mountain retaining wall 1S South side mountain retaining wall 1N North side mountain retaining wall 11 Core material 2 Shoring structure 3 Upright 31 Contact part 3E East side upright 3W West side upright 3S South side upright 3N North side riser 31 Contact part 4 Flint 41 Connection position 5 Strut 6 Flint 7' First expansion/contraction device 7' Second expansion/contraction device 8 Jack cover 9 Locking member 10 Construction target area 10a West area 10b Central area 10c East area A inner corner part

Claims (3)

A supporting structure for a retaining wall installed underground,
A fire pit is installed in the corner of the adjacent harakori,
a first telescoping device interposed in at least one of the tummy tucks;
a contact portion where the adjacent ribs contact each other;
A connection position of the flint with respect to the belly riser is arranged between the first expansion and contraction device and the contact portion, and
A shoring structure for a retaining wall, characterized in that a connection position of a strut is arranged on the opposite side of the connection position of the flint across the first expansion and contraction device of the upright . The shoring structure for a retaining wall according to claim 1,
A shoring structure for a retaining wall, characterized in that a second expansion and contraction device is interposed in the flint. The shoring structure for a retaining wall according to claim 1 or 2,
A shoring structure for a mountain-retaining wall, characterized in that the mountain-retaining wall, which is provided with the raised side with the first expansion/contraction device interposed therebetween, is provided with a locking member that locks onto the ground .

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