JP5046742B2 - Retaining wall and its supporting method - Google Patents

Description

The present invention relates to a retaining wall and a method for supporting the retaining wall. More specifically, the present invention relates to a retaining wall for a wet method and a method for supporting the retaining wall, which enable a large footing to be omitted and exhibit high rigidity.

It is necessary to install a retaining wall to prevent the ground from collapsing on cliffs caused by cuts exceeding 2m in height, embankments exceeding 1m in height, etc. Arise. This type of retaining wall consists of a reinforced concrete wall or a wall made of precast products or concrete blocks.

Such retaining walls are usually designed with an overall L-shaped or T-shaped cross section, and a relatively large foundation footing is formed at the bottom of the retaining wall. The foundation footing has a wide contact area for transmitting the load acting on the retaining wall (earth pressure) and the weight of the retaining wall to the supporting ground, and functions to prevent the retaining wall from falling.

Since the foundation footing extends relatively large toward the high ground side, it is necessary to excavate the high ground extensively during the retaining wall construction and backfill the excavated portion after the retaining wall construction. In particular, when a retaining wall is constructed on soft ground, there arises a situation where a large foundation footing must be designed and constructed unrealistically. However, the construction of large foundation footings not only requires excessive construction costs for the concrete work of the foundation footings themselves, but also necessitates extensive excavation and backfilling of the ground. It leads to problems such as labor, increase of moving soil, and instability of backfill soil. In addition, depending on the environment at the construction site, the strata, the topography, the ground properties, or the construction conditions, it may be difficult to construct a large-scale foundation footing.

In order to solve such a problem of foundation footing construction, a retaining wall structure of a dry construction method configured to apply a load to the ground pile and to apply a bending moment on the non-falling side to the parent pile in advance is Japanese Patent No. 28824217. It is disclosed in the issue publication. This retaining wall has a structure in which a reinforced concrete structure weight or beam is formed in the groove by excavating a weight construction groove on the natural ground side, and this weight and the parent pile directly under the retaining wall are connected by a support beam. However, a retaining wall such as a PC plate is formed between the parent piles.
According to such a retaining wall structure, a bending moment acts on the parent pile due to the load of the weight, and the strength of the retaining wall is increased by the adhesive force and frictional force of the supporting beam and the weight against the ground, and thereby the foundation footing. It may be possible to omit the construction.
Patent No. 2824217

However, the retaining wall of Patent Document 1 is a retaining wall of a dry construction method in which a lower end portion of a main pile (steel material) is embedded in the ground and a wall element (such as a PC plate) is spanned between the upper portions of the main pile. However, the earth pressure of the high ground and the weight of the wall component can only be absorbed or supported by the deformation of the wall and the reaction force generated in the locking portion of the parent pile and the wall component. Absent.

Moreover, in the retaining wall of the said patent document 1, the moment of the non-falling side is given to a retaining wall by making a steel bracket protrude from the upper part of a main pile to the high ground side, and building a weight in the front-end | tip part of a bracket. However, the bracket is a linear member, and the joint between the bracket and the parent pile is
It is only a fulcrum for pin support, and therefore the frictional force of the ground cannot be used effectively.

The retaining wall of Patent Document 1 also has a structure in which a main pile (usually an H-shaped steel material used for mountain retaining work (temporary work)), a steel bracket, and a face material such as a PC plate are assembled. It is only provided and each component is not integrated as a rigid body. For this reason, depending on the structure of such a retaining wall, the effect of enduring earth pressure in the entire retaining wall cannot be obtained. In addition, the retaining wall of Patent Document 1 using steel as the shaft assembly member is difficult to avoid rusting of the steel material, and this needs to be improved in terms of the service life of the retaining wall.

The present invention has been made in view of such circumstances, and the object of the present invention is to integrate the components of the retaining wall so that the resistance to the earth pressure of the high ground is effective and long-term as a whole. It is another object of the present invention to provide a retaining wall and a method for supporting the retaining wall that can reduce the amount of excavated soil, waste soil, and backfill soil, and can reliably prevent the retaining wall from falling over.

In order to achieve the above object, the present invention supports the earth pressure of the high ground and prevents the collapse of the high ground.
At intervals in the wall center direction of the retaining wall is placed, the lower end portion reaches the support layer of the ground, and the steel pipe of circular cross-section upper part constitutes the vertical struts extending retaining wall,
Comprising a wall body of a reinforced concrete structure that constitutes the wall body portion of the retaining wall on which earth pressure acts,
The lower end of the steel pipe is closed, and the internal hollow area of the steel pipe is filled with concrete that is continuous with the concrete of the wall body over the entire length of the steel pipe,
The outer diameter of the steel pipe is smaller than the wall thickness of the wall body, and the wall surface on the low ground side and the high ground side of the wall body is a flat wall surface having no column shape ,
The underground part of the support column constitutes a pile that at least partially supports the vertical load and horizontal load acting on the retaining wall and the weight of the wall body by the ground.
An underground beam of a reinforced concrete structure formed by expanding the lower section of the wall body to the low ground side and the high ground side is formed at the lower end of the wall body, and the beam width (W) of the underground beam is It is set to a size larger than the beam of the underground beam (D), the column vertically penetrates the underground beam, and the underground beam interconnects the column and is grounded to the ground. the vertical load, to provide a retaining wall characterized that you configure a direct basis for transferring a portion of the horizontal load and its own weight to the ground.
The present invention also supports a retaining wall that supports the earth pressure of the high ground and supports the retaining wall that prevents the collapse of the high ground by the ground.
The wall of the reinforced concrete structure that constitutes the wall part of the retaining wall on which earth pressure acts is provided, the lower end reaches the support layer of the ground, and the upper part has a circular cross section that constitutes a vertical column extending into the retaining wall Steel pipes are arranged at intervals in the direction of the wall core of the retaining wall,
The lower end of the steel pipe is closed, and the internal hollow area of the steel pipe is filled with concrete that is continuous with the concrete of the wall body over the entire length of the steel pipe,
The outer diameter of the steel pipe is smaller than the wall thickness of the wall body, and the wall surface on the low ground side and the high ground side of the wall body is a flat wall surface having no column shape,
An underground beam having a reinforced concrete structure formed by enlarging the lower cross section of the wall body to the low ground side and the high ground side is formed at the lower end of the wall body, and the beam width (W) of the underground beam is Set to a dimension larger than the beam of the underground beam (D), and the column vertically penetrates the underground beam,
The vertical load and horizontal load acting on the retaining wall, and the weight of the wall body constitute the pile, the frictional force acting between the retaining wall and the ground, the supporting force of the ground support layer with respect to the column. A retaining wall supporting method is provided, wherein the retaining wall is supported by a frictional force between an underground portion of the support column and the ground and a ground strength of the ground to which the underground beam contacts the ground.

According to the above-described configuration of the present invention, the underground beam having a beam width (W) larger than the beam width (D) interconnects the columns, and contacts the ground so that the vertical load, the horizontal load and the own weight of the retaining wall are grounded. Constitutes a direct foundation to transmit a part of the ground to the ground. Moreover, according to the said structure of this invention, the lower part of a vertical support | pillar (steel pipe) comprises a pile, and the upper part of a support | pillar comprises the standing pillar in the wall body integrated with the wall body. The earth pressure of the high ground mainly acts on the wall body, and the load acting on the wall body is transmitted to the ground through the columns and underground beams . The wall body resists corrosion by soil and maintains a desired strength for a relatively long time.

Moreover, according to this invention , concrete is filled into the internal hollow area of a steel pipe (support | pillar) . The column filled with concrete exhibits high axial compression strength, bending strength and deformation performance due to the mutual restraint effect (confined effect) between the hollow steel material and the concrete. For example, local buckling of the hollow steel material is suppressed by the filled concrete, the toughness thereof is improved, and the rigidity of the filled concrete is added to the hollow steel material, thereby improving the rigidity of the entire column. Furthermore, the rust prevention effect inside a steel pipe is acquired by filling concrete.

More preferably, the upright column part, the steel pipe or the upper part of the pile body are interconnected by a horizontal member or a truss structure at the ground level. The truss structure is formed by horizontal horizontal members and diagonal members. The horizontal member and the diagonal member are made of a steel material welded to a steel pipe. The horizontal member or truss structure interconnects the pile portions and improves the rigidity of the entire pile group composed of a plurality of pile portions. A horizontal member or truss structure can be used to set or adjust the position of the pile portion during construction of the retaining wall. Moreover, construction of a horizontal member or a truss structure is also effective in stabilizing or holding the position of the pile portion during construction. The diagonal members may be arranged in a cross brace form (taped form).

Thus, the retaining wall of the present invention constitutes a pile , the vertical load, the horizontal load, and the weight of the wall body, the frictional force acting between the retaining wall and the ground, the supporting force of the ground support layer against the column. The structure is supported by the frictional force between the underground part of the column and the ground and the ground strength of the ground where the underground beam touches, and the resistance to the earth pressure of the high ground is effective and long-term for the entire retaining wall. The pillars filled with concrete and the above-mentioned underground beam reliably prevent the retaining wall from falling down.

Since the retaining wall of the present invention also has a configuration in which a large footing extending to the high ground side is omitted, it is only necessary to excavate only a range where the column and the wall body can be constructed. Therefore, according to the present invention, the ground excavation process and labor can be shortened or reduced, and the amount of excavated soil, waste soil, and backfill soil can be reduced. The reduction of the excavated soil volume is extremely advantageous in practice because it simultaneously eliminates the problems associated with the reduction of the moving soil volume and the instability of the backfill soil. Moreover, since the retaining wall of this invention can apply footing to the terrain where construction is difficult, the applicable range of a retaining wall expands greatly.

According to the retaining wall and the supporting method of the present invention, the constituent elements of the retaining wall are integrated, and the proof strength against the earth pressure of the high ground is exhibited effectively and in the long term as the entire retaining wall. The amount of backfill soil can be reduced, and the retaining wall can be prevented from falling.

Preferably said ground beam, a beam main reinforcement extending Kabeshin direction, and the Sturup muscle surrounding the main reinforcement is reinforcement.

In a preferred embodiment of the present invention, the lower end of the steel pipe (post) is closed by a circular plate having a diameter equivalent to the diameter of the steel pipe. Preferably, the diameter of the steel pipe is set to a dimension of 150 mm or more in consideration of workability during concrete filling. Preferably, the wall thickness of the wall body is set to a dimension of 200 mm or more. The wall body has a uniform wall thickness over its entire height.

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

FIG. 1 is a cross-sectional view showing a basic configuration of a retaining wall according to the present invention, and FIG. 2 is a partial elevation view of a side surface and a front side of the retaining wall. 3 is a cross-sectional view taken along lines II, II-II, and III-III in FIG.

As shown in FIG. 1, the retaining wall 1 is arranged in a planar form corresponding to the topography of the high ground HG, and the left and right ends are bent toward the high ground HG. The retaining wall 1 surrounds the high ground HG and prevents the high ground HG from collapsing or collapsing toward the low ground LG.

The retaining wall 1 includes a steel vertical column 2 having a circular cross section disposed at a predetermined interval in the wall core direction, and a wall body 3 having a reinforced concrete structure. The upper part of the support column 2 is embedded in the wall body 3, and the lower part of the support column 2 penetrates into the ground. The lower part of the wall body 3 has an enlarged cross section, and the enlarged cross section constitutes an underground beam 4 having a reinforced concrete structure extending in the wall length direction along the wall core of the retaining wall 1 . The underground beam 4 constitutes the foundation of the wall 3 and functions to interconnect the columns 2.

As shown in FIG. 2, the column 2, the wall body 3, and the underground beam 4 constitute an integral earth retaining wall that can withstand the earth pressure of the high ground HG. The lower end portion of the support column 2 reaches the support layer S. The vertical load and horizontal load such as earth pressure and seismic force acting on the retaining wall 1 and the weight of the retaining wall 1 are the frictional force acting between the retaining wall 1 and the ground G, and the underground beam 4 is grounded. It is supported by the ground strength of the ground G, the frictional force between the underground portion of the support 2 and the ground G, and the support force of the support layer S on the support 2.

As shown in FIG. 1, the bent portion of the retaining wall 1 is formed with a fuzzy portion 5 such as a concrete beating-up if desired. As shown in FIG. 3C, when a level difference occurs in the ground surface of the low ground LG, the level of the underground beam 4 is changed stepwise or continuously so as to correspond to the ground surface of the low ground LG. It is desirable. As the support 2, a steel pipe having a circular cross section can be suitably used. Hereinafter, a preferred embodiment using a steel pipe having a circular cross section as the support 2 will be described.

  FIG. 4 is a longitudinal sectional view showing a sectional structure of the retaining wall 1 and a sectional view taken along line IV-IV.

The support column 2 is made of a steel pipe having a uniform circular cross section, and the lower portion (pile portion 2a) of the support column 2 is buried in the ground. The lower end portion of the support column 2 preferably reaches the support layer S having an N value of 10 or more. The lower end opening of the support column 2 is closed by a circular blind plate 6, and the blind plate 6 prevents soil and sand from entering the steel pipe that may occur during embedding. Preferably, the circular blind plate 6 has water tightness capable of preventing water from entering the steel pipe, or includes a water tight means such as a water tight seal. The upper part (standing column part 2b) of the support column 2 protrudes upward from the low ground LG to the level of the ground surface of the high ground G. Concrete 8 is filled in the internal hollow region of the column 2. The diameter of the steel pipe constituting the support column 2 is preferably set in the range of 100 mm to 300 mm. In consideration of the workability of filling concrete, it is desirable to set the diameter of the steel pipe to 150 mm or more. In this example, the diameter of the steel pipe is set to about 170 mm. Preferably, the struts 2 are interconnected by a truss structure 20 as shown in FIG. As an upper and lower horizontal horizontal member (upper chord member, lower chord member) constituting the truss structure 20 and an oblique member (lattice member) in the form of cross braces (shaking form), a steel material, for example, FB− whose end is welded to a steel pipe A flat bar of about 6 × 50 can be preferably used. As the horizontal horizontal member and the diagonal member, a structural steel such as an angle steel, a steel pipe having a small cross section, a round steel, a reinforcing bar, or the like can be used. The truss structure 20 interconnects the separated steel pipes and improves the rigidity of the entire pile group composed of a plurality of steel pipes. The truss structure 20 can also be used to set or adjust the position of the steel pipe during the construction of the retaining wall 1. The construction of the truss structure 20 is also effective in stabilizing or holding the steel pipe position during construction.

The wall body 3 is a wall body of a reinforced concrete structure in which vertical and horizontal wall bars 3a are arranged. The wall thickness of the wall body 3 is preferably set in the range of 250 mm to 400 mm. In this example, the wall thickness of the wall body 3 is set to 300 mm. As the wall reinforcement 3a, general-purpose deformed reinforcing bars of about D10 to D16 are used, and the wall reinforcement interval is set to about 150 mm to 300 mm. In this example, a deformed reinforcing bar of D13 is used as the wall reinforcement 3a, and the interval between the wall reinforcements 3a is set to 250 mm. Vertical stripe constituting the wall muscle 3a extends into the ground beam 4 is fixed to the concrete ground beams 4. A water permeable mat 7 is disposed on the back surface of the wall 3. Further, the wall core CW of the wall body 3 intersects the vertical center axis CL of the column 2 .

Underground beam 4 includes a main reinforcement 4a extending Kabeshin direction consists beam-type member of reinforced concrete structures Haisuji the Sturup muscle 4b surrounding the main reinforcement 4a, the lower surface of the ground beam 4, the discarded concrete and quarrying like Make contact with the leveled excavated ground surface. A general-purpose deformed reinforcing bar of about D13 to D25 can be used as the main reinforcing bar 4a, and a general-purpose deformed reinforcing bar of about D10 to D13 can be used as the stirrup muscle 4b. In this example, a deformed reinforcing bar of D13 is used as the main muscle 4a and the stirrup muscle 4b. The width W of the underground beam 4 is generally set to about 400 to 600 mm, and is set to 500 mm in this example. The height D of the underground beam 4 is generally set to about 200 to 400 mm, and is set to 250 mm in this example.

Thus, the wall 3 and the underground beam 4 constitute an integral reinforced concrete structure, and the width W of the underground beam 4 is much smaller than the width (depth) of the footing in the conventional retaining wall. Is set.

  5, 6, and 7 are vertical cross-sectional views showing the method of installing the retaining wall 1 in stages.

As shown in FIG. 5, the high ground HG is excavated for the construction of the column 2, the wall body 3 and the underground beam 4. In the construction of the retaining wall 1, the excavation range of the high ground G is limited to the minimum range in which the support column 2, the wall body 3 and the underground beam 4 can be constructed. That is, in the construction of the retaining wall 1, unlike the conventional retaining wall construction method, it is not necessary to excavate the high ground HG for the footing construction.

After excavating the pile hole with a pile driving machine combined with an auger, the steel pipe pile is press-fitted into the ground, the steel pipe pile is embedded to a position where the tip of the steel pipe pile slightly bites into the support layer S, and the column 2 is constructed. The upper part of the steel pipe pile constructed as the support column 2 protrudes upward from the excavated ground, and the upper part of the support column 2 is formed by the steel pipe pile.

After leveling the excavated ground with abandoned concrete, quarrying, etc., as shown in FIG. 6, the wall 3 and the wall bars 3a, main bars 4a, and stirrup bars 4b of the underground beam 4 are arranged, and a formwork 9 for concrete work is provided. Is built. After completing the construction of the mold 9, the concrete 8 is poured from the upper part of the mold 9. As shown in FIG. 7, the concrete 8 is not only filled into the mold 9, but also flows into the column 2 through the upper opening of the column 2 and completely fills the internal hollow area of the column 2.

After the concrete is hardened, the formwork 9 is disassembled and the excavated soil is backfilled, whereby the retaining wall 1 shown in FIG. 4 is completed.

According to the retaining wall 1 having such a configuration, most of the weight and load of the retaining wall 1 are transmitted to the support layer S by the support column 2, so that the conventional large footing can be omitted. Can limit the excavation range and reduce the amount of excavated soil, waste soil and backfill soil. The wall body 3 and the underground beam 4 interconnect the support columns 2 to improve the rigidity of the retaining wall 1 as a whole and work as an integral retaining wall that can withstand the earth pressure of the high ground HG.

In particular, the retaining wall 1 uses the supporting force of the supporting layer S to support horizontal loads (such as earth pressure and seismic force) acting on the retaining wall 1, so that the ground can be liquefied during an earthquake. When the retaining wall 1 of the present invention is constructed on the ground, high earthquake resistance that cannot be achieved by the conventional retaining wall can be obtained.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications or changes can be made within the scope of the present invention described in the claims. Is possible.

The retaining wall of the present invention is not limited to a linear retaining wall, and can be constructed as various types of retaining walls, such as a curved retaining wall and a retaining wall that is bent at an angle in a complicated manner.

  Moreover, you may arrange | position a drain hole etc. in an appropriate place in a retaining wall.

The present invention is applied to a retaining wall constructed on a cliff, a steep slope, a water channel or the like. The retaining wall of the present invention is
Since construction of large footings is not required, the workability of retaining walls is greatly improved. Moreover, according to this invention, the vertical retaining wall perpendicular | vertical to the ground which was difficult to construct with the conventional retaining wall can be constructed.
In addition, the present invention enables a retaining wall renovation work and the like that further constructs a retaining wall on the existing retaining wall. In addition, when the retaining wall of the present invention is applied to soft ground where liquefaction of the ground can occur at the time of an earthquake, a high earthquake resistance that cannot be achieved by a conventional retaining wall can be obtained, and its benefit is remarkable.

It is a cross-sectional view which shows the basic composition of the retaining wall of this invention. FIG. 2 is a partial elevational view of a side wall side and a front side of the retaining wall shown in FIG. 1. It is sectional drawing in the II line of FIG. 1, the II-II line, and the III-III line. It is the longitudinal cross-sectional view which shows the cross-section of a retaining wall, and IV-IV sectional view. It is a longitudinal cross-sectional view which shows the construction method of a retaining wall, and the pile driving process of a steel pipe pile is shown. It is a longitudinal cross-sectional view which shows the construction method of a retaining wall, and the bar arrangement and formwork process is shown. It is a longitudinal cross-sectional view which shows the construction method of a retaining wall, and the concrete placement process is shown.

Explanation of symbols

1 Retaining wall
2 columns 3 walls 4 underground beams 2a piles 2b uprights 20 truss structures
HG High Ground LG Low Ground

Claims (4)

In the retaining wall that supports the earth pressure of the high ground and prevents the collapse of the high ground,
At intervals in the wall center direction of the retaining wall is placed, the lower end portion reaches the support layer of the ground, and the steel pipe of circular cross-section upper part constitutes the vertical struts extending retaining wall,
Comprising a wall body of a reinforced concrete structure that constitutes the wall body portion of the retaining wall on which earth pressure acts,
The lower end of the steel pipe is closed, and the internal hollow area of the steel pipe is filled with concrete that is continuous with the concrete of the wall body over the entire length of the steel pipe,
The outer diameter of the steel pipe is smaller than the wall thickness of the wall body, and the wall surface on the low ground side and the high ground side of the wall body is a flat wall surface having no column shape ,
The underground part of the support column constitutes a pile that at least partially supports the vertical load and horizontal load acting on the retaining wall and the weight of the wall body by the ground.
An underground beam of a reinforced concrete structure formed by expanding the lower section of the wall body to the low ground side and the high ground side is formed at the lower end of the wall body, and the beam width (W) of the underground beam is It is set to a size larger than the beam of the underground beam (D), the column vertically penetrates the underground beam, and the underground beam interconnects the column and is grounded to the ground. the vertical loads, retaining wall portions of the horizontal load and its own weight, characterized that you configure a direct basis to transmit to the ground. Wherein the ground beams, retaining wall according to claim 1, characterized in that the beam main reinforcement extending Kabeshin direction, and the Sturup muscle surrounding the main muscle is Haisuji.   The retaining wall according to claim 1 or 2, wherein the wall body has a uniform wall thickness over the entire height. In the supporting method of the retaining wall that supports the earth pressure of the high ground and supports the retaining wall that prevents the collapse of the high ground by the ground,
  The wall of the reinforced concrete structure that constitutes the wall part of the retaining wall on which earth pressure acts is provided, the lower end reaches the support layer of the ground, and the upper part has a circular cross section that constitutes a vertical column extending into the retaining wall Steel pipes are arranged at intervals in the direction of the wall core of the retaining wall,
  The lower end of the steel pipe is closed, and the internal hollow area of the steel pipe is filled with concrete that is continuous with the concrete of the wall body over the entire length of the steel pipe,
  The outer diameter of the steel pipe is smaller than the wall thickness of the wall body, and the wall surface on the low ground side and the high ground side of the wall body is a flat wall surface having no column shape,
  An underground beam having a reinforced concrete structure formed by enlarging the lower cross section of the wall body to the low ground side and the high ground side is formed at the lower end of the wall body, and the beam width (W) of the underground beam is Set to a dimension larger than the beam of the underground beam (D), and the column vertically penetrates the underground beam,
  The vertical load and horizontal load acting on the retaining wall, and the weight of the wall body constitute the pile, the frictional force acting between the retaining wall and the ground, the supporting force of the ground support layer with respect to the column. A retaining wall supporting method, wherein the retaining wall is supported by a frictional force between an underground portion of the support and the ground and a ground strength of the ground to which the underground beam contacts the ground.

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