JP6826820B2 - Insertion pile type retaining wall - Google Patents

Description

The present invention relates to an earth retaining wall in which a resistance moment is generated by utilizing the weight of earth and sand on the back surface side to increase the applicable excavation depth as compared with the conventional self-supporting earth retaining wall.

Conventionally, when constructing an underground structure by excavation work, an earth retaining wall is constructed around the structure and the ground is dug down. If a self-supporting earth retaining wall (see Fig. 15 (A)) that resists earth pressure by the horizontal ground resistance of the rooting part into the ground can be adopted as the earth retaining wall, it is footingless, so the amount of natural modification In addition to having the advantage of being able to reduce the size of the ground and being excellent in dealing with the land boundary problem, excavation is easy because there is no support work on the internal space side, and there are obstructive members (support work, etc.) inside when the construction is completed. Since an open space can be created, it has the advantage of greatly improving workability when constructing underground structures.

However, since the self-supporting earth retaining wall has a structure that resists earth pressure by the horizontal ground resistance of the rooting part into the ground, there is a problem that it can be applied only when the ground is relatively good and the excavation depth is shallow. .. Therefore, in deep excavation work, girder type support (see Fig. 15 (B)), ground anchor type support (see Fig. 15 (C)), tie rod type support (see Fig. 15 (D)), etc. The type of earth retaining wall is adopted. However, in the case of these support-type earth retaining walls, there are problems such as high cost for erection / removal of support, long construction period, and poor construction efficiency of the main structure.

Therefore, in Non-Patent Document 1 below, as shown in FIG. 16, the self-supporting earth retaining wall, which has been conventionally constructed vertically, is tilted toward the back side (approximately 3 to 10 °) to form the earth retaining wall. A self-supporting earth retaining wall 50 has been proposed and implemented that reduces the acting earth pressure and makes it applicable to deep excavation work (approximately 15 m).

Shunji Aoki, 3 outsiders, "Design and construction of diagonal self-supporting earth retaining by parent pile horizontal sheet pile format", Civil Engineering Construction Technology Presentation Summary 2012, Japan Society of Civil Engineers, 2012.11, p.259-263

The diagonally self-supporting earth retaining wall 50 can effectively reduce earth pressure by inclining the main pile, which has been conventionally constructed vertically, toward the back side, and the excavation depth can be expanded to about 15 m. Became.

However, since the excavation area of the diagonal self-supporting earth retaining wall 50 is expanded to the outside by the amount that the main pile is inclined to the back side, the site boundary may be expanded or the site boundary may be restricted depending on the construction conditions. In some cases it was necessary to narrow the excavation area.

In addition, since the construction of the main pile requires that it be driven in an oblique direction, for example, a machine equipped with a hydraulic high-frequency vibro having a center hole structure attached to the leader of a medium-sized three-point pile driver is used, and the leader is tilted. However, there was a problem that a great deal of labor was required to manage the inclination of the main pile. Further, when the wall height of the earth retaining wall is increased, the cross-sectional dimension of the main pile is increased, which causes a problem that the construction cost is increased and it becomes uneconomical.

On the other hand, among the above-mentioned support earth retaining walls, for the ground anchor type support and the pile tie rod type support, an open space can be created without any obstructive members (support, etc.) inside. However, the ground anchor type support work has a drawback that the construction cost is high and the construction period is prolonged because the anchor work is involved. The same applies to the pile tie rod type support work, which has the disadvantages of increasing the construction cost and prolonging the construction period because the construction work on the back side of the retaining wall is involved.

Therefore, the main problem of the present invention is to increase the excavation depth as compared with the conventional self-supporting retaining wall by generating a resistance moment by utilizing the weight of the earth and sand on the back side, and the construction period is excellent and the construction period is excellent. The purpose is to provide a retaining wall with advantages such as not causing a long period of time.

In order to solve the above problems, as the present invention according to claim 1, the main piles are arranged in the horizontal direction at predetermined intervals and the lower half portion is inserted into the ground, and the vertical direction is between the main piles and the adjacent parent piles. An insertion pile made of H-shaped steel , which is installed along the horizontal sheet pile and is inserted into the ground on the back side from the side position of the main pile, and the insertion source side is rigidly connected to the main pile. It is an insertion pile type earth retaining wall equipped with
The insertion piles are installed for each parent pile, and are arranged in pairs on both sides of the parent pile at each location.
H-shaped steel having a size that fits between the flanges of the main pile so that the mounting angle to the main pile does not change even when the inserted pile receives a soil loading load at the mounting portion of the inserted pile to the main pile. With the use of bolts and nuts, connecting hardware having a slit groove into which the flange of the insertion pile can be inserted is attached to both sides of the web of the main pile using bolts and nuts, and the insertion pile has a flange on one side of the slit groove. Provided is an insertion pile type retaining wall that is inserted into the ground in a state of being fitted to the insertion pile, and the web of the insertion pile is rigidly connected to the flange of the connecting metal by bolts and nuts. To.

The invention according to claim 1 is arranged in the horizontal direction at predetermined intervals, and is installed along the vertical direction between a parent pile whose lower half is inserted in the ground and an adjacent parent pile. A horizontal insertion pile that is installed in the back ground from the side position of the main pile with respect to a general earth retaining wall consisting of a horizontal sheet pile, and the insertion source side is rigidly connected to the main pile. Is to be added.

Therefore, the overlay soil existing above the insertion pile acts as a load on the insertion pile, so that a resistance moment in the rotational direction that suppresses the deformation of the parent pile can be generated in the insertion pile, and this resistance moment is the parent. By being transmitted to the pile, it becomes possible to cancel the bending moment generated in the parent pile due to soil pressure, so it is possible to expand the applicable excavation depth compared to the conventional self-supporting retaining wall. Become. Further, in the normal case, the insertion pile can be added by a relatively simple construction from the internal space side every time during excavation, so that it is excellent in economy and does not lead to a long construction period.

The term "rigid connection" in the present invention refers to a connection structure in which the insertion pile is firmly connected so that the mounting angle with respect to the parent pile does not change even when a load is applied, and as a result, the insertion pile is inserted. The resistance moment generated in the pile can be reliably transmitted to the parent pile.

Further, the invention according to claim 1 has a structure in which the insertion piles are arranged in pairs on both sides of the main pile at each location. Since the resistance moment generated in the insertion pile is generated by the loaded soil load, it is effective to increase the amount of soil load acting on the insertion pile in order to increase the resistance moment. Therefore, the loading soil load can be increased by providing a pair of left and right insertion piles with the parent pile sandwiched between them, rather than providing only one on one side of the main pile, and as a result, the resistance moment can be increased.

According to the second aspect of the present invention, the insertion piles are installed in a plurality of stages in the height direction, and are relatively relative to the insertion piles located on the upper side between the insertion piles adjacent in the vertical direction. The insertion pile type retaining wall according to claim 1, wherein the insertion pile located on the lower side has a longer insertion length is provided.

According to the second aspect of the present invention, when the insertion piles are installed in a plurality of stages in the height direction, the insertion piles are relatively relative to the insertion piles located on the upper side between the insertion piles adjacent in the vertical direction. The insertion pile located on the lower side has a structure in which the insertion length is set longer. As for the loading soil load acting on the insertion pile, the upper sediment in the section corresponding to the insertion length acts as a load in the gravity direction, so that the loading soil load acting on the insertion pile located relatively lower is relative. In the section on the front side of the tip of the insert pile located on the upper side, the load on the soil is significantly reduced because the insert pile is located on the upper side, and further behind the tip of the insert pile located on the upper side. The overlaid sediment in the ground section will work effectively. Therefore, unless the insertion pile located on the lower side is made longer than the insertion length of the insertion pile on the upper side, a resistance moment due to the soil loading load is effectively generated on the insertion pile located on the lower side. Therefore, as in the present invention, the insertion pile located on the lower side is inserted more than the insertion pile located on the upper side between the insertion piles adjacent in the vertical direction. It is desirable to set the length long.

According to the third aspect of the present invention, the insertion pile type earth retaining wall according to any one of claims 1 and 2 which is made into a main structure by stretching a precast plate on the outer surface of the insertion pile type earth retaining wall. Provided.

According to the third aspect of the present invention, when the insertion pile type earth retaining wall according to the present invention is used as the main structure, a precast plate is stretched on the outer surface of the earth retaining wall. For example, it is effective when applied as a retaining wall, embankment retaining wall, or leaning retaining wall of a moat-wari road when constructing a grade separation road.

As described in detail above, according to the present invention, by generating a resistance moment by using the weight of earth and sand on the back side, the excavation depth can be increased as compared with the conventional self-supporting earth retaining wall, and the excavation depth is excellent. At the same time, it will be possible to provide a retaining wall with advantages such as not causing a long construction period.

It is a structural perspective view which shows the insertion pile type earth retaining wall 1 which concerns on this invention (the construction procedure of a horizontal insertion pile is included in a part). It is a load action diagram on the horizontal insertion pile 4 for demonstrating the action effect of the insertion pile type earth retaining wall 1. The connecting hardware 5 is shown, (A) is a front view, (B) is a plan view, and (C) is a side view. (A) is a perspective view showing an attached state of the connecting hardware 5, and (B) is a perspective view showing an attached state of the horizontal insertion pile 4. It is a construction procedure figure of the insertion pile type earth retaining wall 1. It is a figure which shows the construction procedure of the insertion pile 4. It is a procedure diagram (A) (B) in the case of massaging and loosening the ground into which the insertion pile 4 is inserted in advance. It is a procedure diagram (A)-(C) which shows the procedure of kneading and loosening by a mechanical expansion stirrer. It is a side view which shows the structure when the insertion pile type earth retaining wall 1 is used as a main structure. It is the enlarged cross-sectional view. It is a cross-sectional view when the insertion pile type earth retaining wall 1 is used as a main structure and is applied to the retaining wall of a moat split road. It is a cross-sectional view (A) (B) when the insertion pile type retaining wall 1 is used as a main structure and is applied to the embankment retaining wall. It is a cross-sectional view of the case where the insertion pile type retaining wall 1 is used as a main structure and applied to a leaning retaining wall. It is a cross-sectional view when the ground anchor is added to the insertion pile type earth retaining wall 1. It is schematic cross-sectional view which shows various conventional earth retaining walls (A) to (D). It is a schematic sectional drawing which shows the conventional diagonal self-supporting earth retaining wall 50.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Structure of insertion pile type earth retaining wall 1]
The insertion pile type earth retaining wall 1 according to the present invention is arranged in the horizontal direction at predetermined intervals, and the lower half portion is inserted into the ground with the main piles 2, 2 ... And the adjacent main piles 2, 2 The horizontal sheet piles 3, 3 ... Installed along the vertical direction between them are installed in the back ground from the side position of the main pile 2, and the insertion source side is rigidly connected to the main pile 2. It is composed of the inserted piles 4 and 4 which are formed.

Hereinafter, details will be specifically described based on the drawings.

The main pile 2 is a structural member for resisting earth pressure, and is usually driven in the vertical direction, and the lower half portion is inserted into the ground. As the member to be used, an H-shaped rope generally used for a self-standing earth retaining wall, a main pile horizontal sheet pile earth retaining wall, and the like is preferably used. The cross-sectional dimensions of this H-shaped rope are selected according to the wall height, but those of about H300 to H500 are often used. Before excavating the ground, the parent pile 2 is driven into the ground by a pile driver at predetermined intervals in the horizontal direction along the boundary line of the excavation area. The interval is about 1.0 to 2.0 m.

In the case of the conventional self-supporting earth retaining wall, the earth pressure is resisted only by the horizontal ground resistance of the rooting portion L of the parent pile 2 into the ground, but in the case of the insertion pile type earth retaining wall 1 according to the present invention, the earth pressure is resisted. Since the structure is such that the horizontal ground resistance of the rooting portion into the ground resists the earth pressure by the cooperative action of the resistance moment of the insertion pile 4, if the wall height is the same, the length of the rooting portion L is long. It is possible to set the height shorter than that of the conventional self-standing earth retaining wall, and the cross-sectional dimension of the main pile 2 can be made relatively small.

The horizontal sheet piles 3 and 3 are plate materials that are sequentially fitted between the main piles 2 and 2 during excavation to retain soil. Usually, wood such as Karamatsu is mainly used.

The insertion pile 4 is a member specially added in the present invention. The insertion piles 4 are installed in one or a plurality of stages in the height direction. In the example of FIG. 1, an example of installing in two stages in the vertical direction is shown. As the insertion pile 4, H-shaped steel having a cross section of about H200 to H400 can be preferably used. The number of steps and the insertion depth of the insertion pile 4 are determined by a design calculation based on the allowable deformation amount at the top of the main pile 2, but in a normal case, about 2 to 4 steps in the height direction. The insertion depth is about 2 to 5 m.

The insertion pile 4 is installed on each parent pile 2 at each predetermined excavation stage as the excavation progresses. The number of installations per location can be one, but as shown in the illustrated example, arranging one pair on both sides of the main pile 2 in one location will ensure a large resistance moment. Is desirable. For installation, the main pile 2 is inserted into the ground along a substantially horizontal direction from the side position, and the insertion source side is rigidly connected to the main pile 2. As shown in FIG. 2, the main pile 2 and the insertion pile 4 are rigidly connected so that the resistance moments M ₁ and M ₂ generated in the insertion pile 4 are reliably transmitted to the main pile 2. This is because, in order to form a rigid connection structure, at the mounting portion of the insertion pile 4 to the main pile 2, the mounting angle to the main pile 2 does not change even when the insertion pile 4 receives a loading load. It is firmly connected by a plurality of bolts and nuts via the connecting hardware 5 described later, or is firmly connected by welding or the like. Further, although the insertion direction of the insertion pile 4 is basically the horizontal direction, it may be installed with a slight inclination including a construction error.

FIG. 3 shows an example of the connecting hardware 5 for connecting the insertion pile 4 to the parent pile 2.

As the connecting hardware 5 shown in the figure, a hardware obtained by processing an H-shaped rope is used. The cross section of the H-shaped steel has a size that fits between the flanges of the main pile 2, and the reinforcing ribs 20a are attached to the center in the height direction, and the slit grooves 20b and 20c into which the flanges of the insertion pile 4 can be inserted are provided at the vertical positions of the reinforcing ribs 20a, respectively. It is formed. The connecting hardware 5 is firmly attached to both sides of the main pile 2 across the web using bolts, nuts 21, 21 ... FIG. 4A also shows a state in which the connecting hardware 5 is attached to the main pile 2.

The insertion pile 4 is inserted into the ground with a flange on one side fitted in the slit grooves 20b, 20c, and is rigidly connected to the connecting hardware 5 by bolts, nuts 22, 22 ... FIG. 4B also shows a state in which the insertion pile 4 is connected to the connecting hardware 5.

By installing the insertion pile 4, as shown in FIG. 2, the soil load above the insertion pile 4 can act as a loading load, and the resistance moment M _{1 in the} direction of suppressing the deformation of the main pile 2 can be applied. , M ₂ can be generated, and the resistance moments M ₁ and M ₂ are transmitted to the main pile 2, so that the amount of deformation of the main pile 2 can be suppressed. Therefore, it is possible to increase the applicable excavation depth as compared with the conventional self-supporting retaining wall. Further, as will be described later, since the construction of the insertion pile 4 can be added by a relatively simple construction from the internal space side, it is excellent in economy and does not lead to a long construction period.

As in Figure 1 and details are shown in Figure 2, when installed in a plurality of stages in the height direction, the insertion is located in the relatively upper side between the insertion pile 4 _1, 4 ₂ which are adjacent in the vertical direction The insertion length of the insertion pile 4 ₂ located relatively lower than the pile 4 ₁ is set to be longer. Throat load on acting on the insert pile 4 ₁ of the first row from the top, but the upper sediment section corresponding to the insertion length acts as a load in the direction of gravity, for the insertion pile 4 ₂ 2 stage, In the section on the front side of the tip of the first-stage insertion pile 4 ₁ , the insertion pile 4 ₁ exists on the upper side, so that the loading soil load is significantly reduced and compared to the tip of the first-stage insertion pile 4 _1. Furthermore, the sediment on the ground section on the back side will work effectively. Therefore, if the direction of insertion piles 4 ₂ positioned relatively lower side unless longer than the upper insertion pile 4 ₁ insertion length, the resistance by the upper throat load inserted piles 4 ₂ positioned on the lower side since it becomes impossible to generate a moment M ₂ effectively, between inserted pile 4 _1, 4 ₂ which are adjacent in the vertical direction, relatively lower than the insertion pile 4 ₁ positioned relatively upper side it is desirable to insert towards the insertion piles 4 ₂ located on the side length is set longer. In the case of three-stage arrangement or more, the insertion length of the insertion pile 4 is set to gradually increase in the order of the first stage, the second stage, and the third stage from the upper side.

Next, the construction procedure and procedure of the insertion pile type retaining wall 1 will be described in detail with reference to FIGS. 5 to 8.

First, as shown in FIG. 5A, H-shaped ropes to be the main pile 2 are driven into the ground by a construction machine such as a pile driver at predetermined intervals along the excavation boundary line.

Next, the area surrounded by the main pile 2 is excavated by an excavator such as a power shovel. As the excavation progresses, horizontal sheet piles 3, 3 ... Are laid between the main piles 2 and 2, and the excavation is gradually carried out while retaining the soil. As shown in FIG. 5B, if excavation is performed to a predetermined depth, that is, a position slightly deeper than the installation position of the first-stage insertion pile 4, the first-stage insertion piles 4, 4, ... Start the installation work.

For the construction of the insertion pile 4, for example, the pile press-fitting machine 10 in the horizontal direction shown in FIG. 6 is used, and the insertion pile 4 is basically inserted into the back ground side by press-fitting. The pile press-fitting machine 10 has a horizontally oriented guide cell 12 mounted on a travelable crawler carriage 11, a drifter 13 that can move forward and backward along the guide cell 12, and a press-fitting reaction force receiving penetration pile 14. It is a device provided, and the insertion pile 4 is press-fitted into the ground by advancing the drifter 13 from the state where the insertion pile 4 is set in the guide cell 12.

Further, when the back ground is relatively good and the insertion pile 4 cannot be installed in the ground only by press fitting, it is desirable to use the auxiliary construction method together. This auxiliary construction method refers to a work of kneading and loosening the earth and sand in the insertion range of the insertion pile 4 before press-fitting so that the insertion pile 4 can be easily press-fitted. Specifically, as shown in FIG. 7 (A), the small-diameter auger is rotated within the cross section of the insertion pile 4 (the cross section of the H-shaped steel in the illustrated example) by using the pile press-fitting machine 10 described above. While kneading the earth and sand by penetrating it, as shown in FIG. 7 (B), the earth and sand in a circular range including the cross section of the insertion pile 4 (the cross section of the H-shaped steel in the illustrated example) is squeezed using a mechanical expansion stirrer. By kneading and loosening in one step, the ground is weakened so that the insertion pile 4 can be press-fitted.

As the mechanical diameter-expanding stirrer, for example, as shown in FIG. 8, when the stirring rod 15 is penetrated into the ground from the position adjacent to the main pile 2 to the inner side, the diameter-expanding bit 15a is expanded. After that, a device capable of kneading and loosening the ground in the expanded range by pulling it toward the front while rotating it can be used. As such a device, for example, in the anchor construction method, a machine for creating an enlarged anchor body in the ground can be applied as it is.

When the installation work of the first stage insertion piles 4, 4 ... is completed, excavation is started and the ground is gradually dug down while installing the horizontal sheet pile 3 as shown in FIG. 5 (C). After excavating to a position slightly deeper than the installation position of the second-stage insertion pile 4, the installation work of the second-stage insertion pile 4, 4, ... Is started. The installation procedure is the same as for the first stage.

When the installation work of the second stage insertion piles 4, 4 ... is completed, the excavation work is completed by excavating to a predetermined depth.

[Application example in which the insertion pile type earth retaining wall 1 is used as the main structure]
As described above, the insertion pile type earth retaining wall 1 is applied as a temporary structure for earth retaining, and can also be used as it is as a main structure. Specifically, as shown in FIG. 9, precast plates 6, 6 ... Are stretched on the front side of the main pile 2 so as to cover the entire wall surface. It is preferable to install the precast plates 6, 6 ... From the lower stage side to the upper stage side. After that, as shown in FIG. 10, concrete 7 is placed in the closed space sandwiched between the horizontal sheet pile 3 and the precast plate 6 between the main piles 2 and 2, while the drainage hole is provided in a part of the closed space. (Pipes) 8 and 8 are arranged and crushed stone 9 is filled so as to function as a water permeable layer. When the mainland retaining wall 1 is used as an impermeable wall, concrete 7 is placed in all the closed spaces to ensure impermeable.

(Application to retaining wall of Horiwari road)
As shown in FIG. 11, for example, the mainland retaining wall 1 as the main structure can be applied as a retaining wall of a moat split road of a grade separation road. In this case, (1) Since the retaining wall is basically constructed by the prefabricated method, the construction period can be shortened. (2) Since it is a combined construction method of temporary construction and permanent construction, the occupied width at the time of construction can be reduced and the turning of existing roads can be significantly reduced. (3) Since the excavation width and depth can be made smaller than those of the conventional method, there are advantages such as reduction of the amount of excavated residual soil.

(Application to embankment retaining wall)
The mainland retaining wall 1 as the main structure is, for example, a retaining wall for embankment in a constructed ground or the like as shown in FIG. 12 (A), or a retaining wall for abdominal embankment as shown in FIG. 12 (B). Can be applied as. In this case, it is more economical than the conventional embankment retaining wall such as L-shaped retaining wall and reinforced soil.

(Application to leaning retaining wall)
The mainland retaining wall 1 as the main structure can be applied as a leaning retaining wall, for example, as shown in FIG. In this case, the earth pressure becomes small and the structural scale can be reduced, so that the economy and workability become excellent.

[Other form examples]
(1) The insertion pile type earth retaining wall 1 according to the present invention is basically a structure composed of the main pile 2, the horizontal sheet pile 3, and the insertion pile 4, but may be used in combination with other support works in some cases. It is also possible to do. For example, as shown in FIG. 14, in the case of deep excavation, the combined use of the ground anchor 16 makes it more economical than other construction methods, and when there are buried objects adjacent to each other, the ground is used. By using the anchor together, the deformation of the ground can be suppressed. It can also be used in combination with the above-mentioned pile pile tie rod.

1 ... Insert pile type earth retaining wall, 2 ... Parent pile, 3 ... Horizontal sheet pile, 4 ... Insert pile, 5 ... Connecting hardware, 6 ... Precast plate, 7 ... Concrete, 8 ... Drain hole (pipe), 9 ... Crushed stone 10, ... Pile press-fitting machine

Claims (3)

A parent pile whose lower half is inserted into the ground while being arranged at predetermined intervals in the horizontal direction, a horizontal sheet pile installed along the vertical direction between adjacent parent piles, and a side of the parent pile. It is an insertion pile type earth retaining wall that is installed in the ground on the back side from the part position and has an insertion pile made of H-shaped steel whose insertion source side is rigidly connected to the parent pile .
The insertion piles are installed for each parent pile, and are arranged in pairs on both sides of the parent pile at each location.
H-shaped steel having a size that fits between the flanges of the main pile so that the mounting angle to the main pile does not change even when the inserted pile receives a soil loading load at the mounting portion of the inserted pile to the main pile. With the use of bolts and nuts, connecting hardware having a slit groove into which the flange of the insertion pile can be inserted is attached to both sides of the web of the main pile using bolts and nuts, and the insertion pile has a flange on one side of the slit groove. An insertion pile type retaining wall that is inserted into the ground in a state of being fitted to the insertion pile, and the web of the insertion pile is rigidly connected to the flange of the connecting metal by bolts and nuts . The insertion piles are installed in a plurality of stages in the height direction, and the insertion piles located relatively lower than the insertion piles located relatively above the insertion piles adjacent in the vertical direction. The insertion pile type retaining wall according to claim 1, wherein the insertion length is set to be long. The insertion pile type earth retaining wall according to any one of claims 1 and 2, wherein a precast plate is stretched on the outer surface of the insertion pile type earth retaining wall to form a main structure.

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