JP6444595B2 - Retaining wall and retaining wall construction method - Google Patents

Description

  The present invention relates to a retaining wall and a method for constructing the retaining wall.

  As the earth retaining wall, a wall-like ground improvement body in which a plurality of core materials are embedded is known (for example, see Patent Documents 1 to 4).

JP 2010-196441 A Japanese Unexamined Patent Publication No. 2013-144876 JP 2003-342948 A JP 2007-277830 A

  By the way, the earth pressure which acts on the wall-shaped ground improvement body becomes large as the depth of the ground becomes deep. For this reason, if a plurality of core materials having the same length are embedded uniformly over the entire length of the wall-like ground improvement body, the upper reinforcement of the wall-like ground improvement body becomes excessive, which may be uneconomical.

  In view of the above facts, an object of the present invention is to reduce the cost of a core material for reinforcing a wall-like ground improvement body.

The earth retaining wall according to the first aspect includes a wall-like ground improvement body, a high core material embedded in the wall-like ground improvement body, and the wall-like ground improvement so that a head position is lower than the high core material. And a low-heart material embedded in the body.

According to the earth retaining wall according to the first aspect , the wall is formed according to the earth pressure acting on the wall-shaped ground improvement body by making the low-heart material into the wall-shaped ground improvement body so that the head position is lower than the high core material. The ground improvement body can be reinforced. That is, while the lower part of the wall-like ground improvement body is reinforced with the high core material and the low core material, the upper part of the wall-like ground improvement body can be reinforced with the high core material. Therefore, the cost of the core material for reinforcing the wall-shaped ground improvement body can be reduced as compared with a configuration in which a plurality of high core materials are uniformly embedded in the wall-shaped ground improvement body.

The construction method of the retaining wall according to the second aspect is the method of the earth retaining wall for constructing the concrete underground wall inside the wall-like ground improvement body in which the high core material and the low core material whose head position is lower than the high core material are embedded. In the construction method, a core material burying step of dropping the high core material and the low core material having a column attached to the head into the wall-like ground improvement body before hardening, and the hardened wall-like ground improvement body The inner wall surface is scraped to expose the high core material, the low core material, and the support column, and a separator is fixed to the exposed high core material, the low core material, and the support column, and the formwork for the concrete underground wall is attached. And a formwork installation step.

According to the construction method of the retaining wall according to the second aspect , in the core material burying step, the high core material and the low core material are dropped into the wall-like ground improvement body before hardening. At this time, the low core material is dropped into the wall-like ground improvement body so that the head position is lower than the head position of the high core material. Moreover, the support | pillar is attached to the head of a low core material. This support | pillar is dropped in a wall-like ground improvement body with a low core material, and is embed | buried under the upper part of a wall-like ground improvement body.

  Next, in the mold installation step, the inside of the wall-like ground improvement body is scraped off to expose the high core material, the low core material, and the support column. And a separator is fixed to the exposed high core material, low core material, and a support | pillar, and the formwork for concrete underground walls is attached.

  In this way, in the present invention, by embedding the high core material and the low core material in the wall-like ground improvement body, the wall-like ground improvement body can be reinforced according to the earth pressure acting on the wall-like ground improvement body. More specifically, the lower portion of the wall-shaped ground improvement body can be reinforced with the high core material and the low core material, while the upper portion of the wall-shaped ground improvement body can be reinforced with the high core material. Therefore, the cost of the core material for reinforcing the wall-shaped ground improvement body can be reduced as compared with a configuration in which a plurality of high core materials are uniformly embedded in the wall-shaped ground improvement body.

  Moreover, the support | pillar attached to the head of a low core material is embed | buried under the upper part of a wall-shaped ground improvement body. By fixing the separator to the column and the high core material, the pitch of the separator in the upper part of the wall-like ground improvement body can be made the same as that of the lower part of the wall-like ground improvement body. Therefore, temporary work such as a new formwork support becomes unnecessary, so that the workability of the concrete underground wall can be improved.

The retaining wall construction method according to the third aspect is the retaining wall construction method according to the second aspect , wherein, in the core material embedding step, the temporary core material is detachably attached to the head of the low core material and along the temporary core material. The post disposed in the wall-shaped ground improvement body is dropped together with the low core material and the temporary core material from the head of the low core material. Remove and pull up.

According to the construction method of the retaining wall according to the third aspect , in the core material embedding process, the temporary core material is detachably attached to the head portion of the low core material and the struts arranged along the temporary core material are attached to the head portion of the low core material. It fixes and drops these temporary core materials and support | pillars into a wall-like ground improvement body with a low core material. Therefore, the low core material can be easily dropped into the lower portion of the wall-like ground improvement body by the dead weight of the temporary core material.

  Moreover, the inclination and deformation | transformation of a support | pillar are suppressed by arrange | positioning a support | pillar along a temporary core material and dropping in a wall-shaped ground improvement body with a temporary core material. Therefore, it is possible to embed the column in the wall-like ground improvement body with high accuracy.

The retaining wall construction method according to the fourth aspect is the retaining wall construction method according to the third aspect , wherein in the core material embedding step, the pair of struts are arranged symmetrically with respect to the center of the temporary core material in plan view. To do.

According to the construction method of the retaining wall according to the fourth aspect , the eccentricity of the temporary core material is suppressed by arranging the pair of support columns symmetrically with respect to the center of the temporary core material in a plan view in the core material embedding step. Thereby, when dropping a temporary core material in a wall-shaped ground improvement body, the inclination of a temporary core material and a support | pillar is suppressed. Therefore, it is possible to embed the column in the wall-like ground improvement body with higher accuracy.

  As described above, according to the retaining wall and the retaining wall construction method according to the present invention, the cost of the core material for reinforcing the wall-like ground improvement body can be reduced.

It is a longitudinal cross-sectional view which shows the earth retaining wall which concerns on one Embodiment of this invention. It is sectional drawing corresponding to the 2-2 sectional view taken on the line of FIG. 1 explaining the construction method of the earth retaining wall shown by FIG. It is the front view which looked at the wall-shaped ground improvement body shown by FIG. 1 from the inner side. It is explanatory drawing explaining the method of dropping the low core material shown by FIG. 3 in a wall-shaped ground improvement body. It is explanatory drawing which shows the state which attached the temporary core material to the head of the low core material shown by FIG. It is the top view which looked at the temporary core material shown by FIG. 5 from the top. It is explanatory drawing which shows the state which dropped the low core material and temporary core material shown by FIG. 5 in the wall-shaped ground improvement body. FIG. 8 is a plan view showing a state in which a pair of angles shown in FIG. 7 are temporarily fastened to a pair of horizontal members of a gantry. It is explanatory drawing which shows the state which extracted the temporary core material from the wall-shaped ground improvement body shown by FIG.

  Hereinafter, a construction method of a retaining wall and a retaining wall according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the earth retaining wall 10 includes a wall-like ground improvement body 12 and a concrete underground wall 32 constructed inside the wall-like ground improvement body 12. The wall-like ground improvement body 12 is formed of soil cement. The wall-shaped ground improvement body 12 is formed by, for example, a plurality of columnar ground improvement bodies that are continuously formed in a wall shape in the ground.

  Here, the earth pressure P received by the wall-shaped ground improvement body 12 from the ground 14 increases as the depth of the ground 14 increases. Therefore, in this embodiment, as shown in FIGS. 2 and 3, a plurality of high core materials 16 and low core materials 18 are alternately embedded in the wall-shaped ground improvement body 12 according to the earth pressure P.

  As shown in FIG. 2, the high core material 16 and the low core material 18 are reinforcing materials that impart out-of-plane rigidity to the wall-shaped ground improvement body 12, and are formed of, for example, a shape steel or a steel pipe. In the present embodiment, the high core material 16 and the low core material 18 are formed of H-shaped steel. The high core material 16 and the low core material 18 are embedded in the wall-shaped ground improvement body 12 with the longitudinal direction as the vertical direction and the strong axis direction (facing direction of the flange portions 16A, 18A) as the wall thickness direction of the wall-shaped ground improvement body 12. Has been. Further, the high core material 16 and the low core material 18 are alternately arranged in the in-plane direction of the wall-shaped ground improvement body 12.

  The high core material 16 and the low core material 18 are not necessarily arranged alternately. For example, a plurality of high core materials 16 may be continuous, or a plurality of low core materials 18 may be continuous.

  As shown in FIG. 3, the high core material 16 is disposed over the upper portion 12U and the lower portion 12L of the wall-shaped ground improvement body 12. On the other hand, the low core material 18 is embedded in the lower portion 12 </ b> L of the wall-shaped ground improvement body 12 such that the total length of the low core material 18 is shorter than that of the high core material 16 and the head 18 </ b> H position is lower than the head 16 </ b> H position of the high core material 16. Has been. Thereby, while the lower part 12L of the wall-like ground improvement body 12 where the earth pressure P becomes large is reinforced by the high core material 16 and the low core material 18, the upper part 12U of the wall-like ground improvement body 12 where the earth pressure P becomes small is high. Reinforced by a core material 16.

  In addition, a pair of angles 20 and 22 as an example of a support column are attached to the head 18 </ b> H of the low core material 18. The pair of angles 20 and 22 only need to be able to support a separator 56 described later, and are formed of a member having a member cross section and rigidity smaller than that of the low core material 18. The pair of angles 20 and 22 are arranged on the low core material 18 with the longitudinal direction as the vertical direction, and the lower ends thereof are joined to the head portion 18H of the low core material 18 by welding or the like. Moreover, as FIG. 2 shows, one angle 20 is arrange | positioned among the pair of angles 20 and 22 at the inner wall surface 12A side of the wall-shaped ground improvement body 12, and the other angle 22 is the wall-shaped ground improvement body 12. As shown in FIG. Is arranged on the outer wall surface 12B side. The strut is not limited to the angles 20 and 22, but may be a shape steel, a steel pipe, a flat steel plate, or the like.

  Here, the inner wall surface 12A of the wall-shaped ground improvement body 12 is a substantially flat surface. From this inner wall surface 12A, the high core material 16, the low core material 18, and the flange portions 16A, 18A, 20A of one angle 20 are exposed. A concrete underground wall 32 (see FIG. 1) is constructed on the inner wall surface 12A side of the wall-shaped ground improvement body 12.

  The concrete underground wall 32 is formed of a reinforced concrete structure, for example. The concrete underground wall 32 is an outer wall of the underground structure 30 and is raised from the outer peripheral portion of the foundation slab 34. The concrete underground wall 32 and the wall-shaped ground improvement body 12 are integrated with each other via a plurality of studs (not shown) provided on the flange portions 16A and 18A of the high core material 16 and the low core material 18, and the composite wall. Is configured.

  Next, an example of the construction method of the retaining wall 10 will be described.

  First, in the ground improvement body construction step, the wall-like ground improvement body 12 is constructed on the ground 14. Specifically, a plurality of columnar improvement bodies are continuously formed in a wall shape on the ground 14.

  Next, in the core material embedding process, before the wall-shaped ground improvement body 12 is hardened, a plurality of high core materials 16 and low core materials 18 are dropped into the wall-shaped ground improvement body 12 at a predetermined interval by a crane or the like (not shown). At this time, the low core material 18 is dropped into the wall-shaped ground improvement body 12 together with the temporary core material 42 and the pair of angles 20 and 22.

  Specifically, as shown in FIG. 4, first, only the lower part of the low core material 18 is dropped into the wall-shaped ground improvement body 12 before being hardened by a crane or the like. In this state, the upper part of the low core material 18 is temporarily fastened to the horizontal member 40A of the gantry 40 temporarily installed on the ground 14. In addition, the code | symbol 38 is a construction groove | channel for the wall-shaped ground improvement body 12. FIG.

  Next, the temporary core material 42 is moved above the low core material 18 by a crane or the like (not shown), and as shown in FIG. The lower ends 20L and 22L of the pair of angles 20 and 22 arranged along the temporary core material 42 are attached to the head portion 18H of the low core material 18.

  Here, the configuration of the temporary core material 42 and the pair of angles 20 and 22 will be supplemented. The temporary core material 42 is formed of, for example, the same H-shaped steel as the low core material 18, and a wire rope 44 such as a crane is attached to the head of the temporary core material 42. A gripping tool 46 such as a hydraulic chuck that opens and closes by hydraulic pressure and grips the head portion 18H of the low core material 18 is provided at the lower end of the temporary core material 42, for example. By grasping the head 18H of the low core material 18 by the gripping tool 46, the lower end portion of the temporary core material 42 is detachably attached to the head 18H of the low core material 18. An attachment hole 48 (see FIG. 4) to which the gripping tool 46 is attached is formed in the head 18H of the low core material 18. Reference numeral 50 denotes a hydraulic hose that supplies hydraulic oil to the gripping tool 46.

  The pair of angles 20 and 22 are arranged along the longitudinal direction of the temporary core material 42. The lower ends 20L and 22L of the pair of angles 20 and 22 extend downward from the temporary core material 42 and are joined to the head portion 18H of the low core material 18 by welding or the like.

  Further, as shown in FIG. 6, the pair of angles 20 and 22 are disposed inside the pair of flange portions 42 </ b> A of the temporary core material 42, and the upper end portion is fixed to the flange portion 42 </ b> A by a fixing bracket (clamping bracket) 52. Are temporarily attached to each. The pair of angles 20 and 22 are arranged symmetrically with respect to the center (centroid) C of the temporary core material 42 in plan view. Thereby, when dropping the temporary core material 42 into the wall-shaped ground improvement body 12, the inclination of the temporary core material 42 is suppressed.

  Note that “symmetry” here is a concept that includes not only strict symmetry but also a configuration that deviates from strict symmetry positions due to manufacturing errors, mounting errors, and the like of the pair of angles 20 and 22.

  Next, the upper part of the low core material 18 is removed from the horizontal member 40A of the gantry 40, and the low core material 18, the temporary core material 42, and the pair of angles 20, 22 are fixed to the wall-shaped ground improvement body before hardening as shown in FIG. 12 (arrow a). Thereby, the low core material 18 is dropped into the lower part 12L of the wall-shaped ground improvement body 12, and the position of the head 18H becomes lower than the position of the head 16H of the high core material 16 (see FIG. 3).

  Next, the angles 20 and 22 are respectively removed from the pair of flange portions 42A of the temporary core material 42, and the removed angles 20 and 22 are attached to the pair of horizontal members 40A by the fixing metal fittings (clamping metal fittings) 54 shown in FIG. Temporarily fix each. In addition, in FIG. 8, illustration of the temporary core material 42 is abbreviate | omitted.

  Next, the gripping tool 46 of the temporary core material 42 is removed from the head 18H of the low core material 18, and as shown in FIG. 9, only the temporary core material 42 is pulled up by a crane or the like (arrow b), and the pair of angles 20, 22 are moved. It is left in the wall-shaped ground improvement body 12.

  The above procedure is repeated, the high core material 16 and the low core material 18 are dropped into the wall-shaped ground improvement body 12, and the wall-shaped ground improvement body 12 is hardened. As a result, the high core material 16 and the low core material 18 are embedded in the wall-shaped ground improvement body 12. The upper portions of the pair of angles 20 and 22 are cut at predetermined positions.

  Next, as shown in FIG. 2, in the mold installation step, the inner wall surface 12 </ b> A side of the hardened wall-like ground improvement body 12 is scraped off, and the high core material 16, the low core material 18, and the flange portion 16 </ b> A of one angle 20. , 18A, and 20A are exposed. Then, one end portion of the separator 56 is fixed to the exposed flange portions 16A, 18A, and 20A by welding or the like, and a reinforcing bar or the like is appropriately arranged, and then a panel-shaped form 58 is attached to the other end portion of the separator 56. .

  Next, in the concrete placing step, concrete is placed in the mold 58 and cured. Thereafter, the mold 58 is removed. Thereby, the concrete underground wall 32 is constructed along the wall-shaped ground improvement body 12.

  Next, the effect of this embodiment will be described.

  As shown in FIG. 3, the low core material 18 is embedded in the wall-shaped ground improvement body 12 so that the position of the head 18 </ b> H is lower than the high core material 16. By embedding the low core material 18 and the high core material 16 alternately in the wall-like ground improvement body 12, the wall-like ground improvement body 12 can be reinforced according to the earth pressure P acting on the wall-like ground improvement body 12. it can. That is, the lower portion 12 </ b> L of the wall-shaped ground improvement body 12 can be reinforced with the high core material 16 and the low core material 18, while the upper portion 12 </ b> U of the wall-shaped ground improvement body 12 can be reinforced with the high core material 16.

  Therefore, the material cost of the core material (the high core material 16 and the low core material 18) that reinforces the wall-shaped ground improvement body 12 is reduced as compared with a configuration in which a plurality of high core materials 16 are uniformly embedded in the wall-like ground improvement body 12. be able to.

  On the other hand, when the low core material 18 and the high core material 16 are alternately buried in the wall-like ground improvement body 12, the upper core 12U of the wall-like ground improvement body 12 is free from the low core material 18 and forms a formwork for the concrete underground wall 32. The pitch (interval) of separators 56 that support 58 is increased. Therefore, there is a possibility that the mold 58 cannot be sufficiently supported. In this case, since a temporary form support such as a new formwork support is required, the workability of the concrete underground wall 32 becomes complicated.

  As a countermeasure, in this embodiment, an angle 20 is attached to the head 18H of the low core material 18 and is embedded in the wall-shaped ground improvement body 12 together with the low core material 18. By fixing the separator 56 to the angle 20 and the high core material 16, the pitch of the separator 56 in the upper portion 12U of the wall-like ground improvement body 12 can be made the same as that of the lower portion 12L of the wall-like ground improvement body 12. Therefore, temporary work such as a new formwork support or the like is not required, so that the workability of the concrete underground wall 32 can be improved.

  In the present embodiment, the temporary core material 42 is detachably attached to the head portion 18H of the low core material 18 in the core material embedding step described above. Thereby, the low core material 18 is dropped into the wall-shaped ground improvement body 12 by the dead weight of the temporary core material 42. Therefore, the low core material 18 can be easily dropped into the lower portion 12 </ b> L of the wall-shaped ground improvement body 12.

  Further, by temporarily fastening the pair of angles 20 and 22 to the temporary core material 42 and dropping them into the wall-like ground improvement body 12 together with the temporary core material 42, the inclination and deformation of the pair of angles 20 and 22 are suppressed. Therefore, the pair of angles 20 and 22 can be embedded in the wall-like ground improvement body 12 with high accuracy.

  In addition, by arranging the pair of angles 20 and 22 symmetrically with respect to the center C of the temporary core material 42 (see FIG. 6) in plan view, the eccentricity of the temporary core material 42 is suppressed. Thereby, when dropping the temporary core material 42 and the pair of angles 20, 22 into the wall-like ground improvement body 12, the inclination of the temporary core material 42 and the pair of angles 20, 22 is suppressed. Accordingly, the pair of angles 20 and 22 can be embedded in the wall-like ground improvement body 12 with higher accuracy.

  Next, a modification of the above embodiment will be described.

  In the said embodiment, although the example which fixed the separator 56 to the high core material 16 and the angle 20 in the upper part 12U of the wall-shaped ground improvement body 12 was shown, it does not restrict to this. For example, a cross member may be bridged between the adjacent high core material 16 and the angle 20, and the separator 56 may be fixed to the cross member. Similarly, in the lower part 12L of the wall-shaped ground improvement body 12, a cross member may be bridged between the adjacent high core material 16 and the low core material 18, and the separator 56 may be fixed to the cross member.

  Moreover, although the example which attached a pair of angles 20 and 22 to the head 18H of the low core material 18 was shown in the said embodiment, it is not restricted to this. At least one angle (post) can be attached to the head 18 </ b> H of the low core material 18.

  Moreover, in the said embodiment, although the earth retaining wall 10 showed the example formed with the wall-shaped ground improvement body 12 and the concrete underground wall 32, the concrete underground wall 32 can be abbreviate | omitted suitably.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be used in combination as appropriate, and the gist of the present invention will be described. Of course, various embodiments can be implemented without departing from the scope.

10 Earth retaining wall 12 Wall-shaped ground improvement body 12A Inner wall surface 16 High core material 16H Head 18 Low core material 18H Head 20 Angle (support)
22 angles
32 Concrete underground wall 42 Temporary core material 56 Separator 58 Formwork

Claims (4)

A wall-like ground improvement body,
A high-core material embedded in the wall-like ground improvement body,
A low core material embedded in the wall-shaped ground improvement body so that the head position is lower than the high core material;
And concrete basement walls formed inside the front Kikabejo soil improvement material,
A column attached to the head of the low core material, embedded in the wall-like ground improvement body and arranged along the wall surface of the concrete underground wall,
A separator is fixed to the front Symbol struts are embedded in the concrete basement walls,
A retaining wall with A method for constructing a retaining wall that constructs a concrete underground wall inside a wall-shaped ground improvement body in which a high core material and a low core material having a lower head position than the high core material are embedded,
In the wall-like ground improvement body before hardening, a core material burying step of dropping the high core material and the low core material with a post attached to the head,
The inner wall surface side of the hardened ground improvement body is scraped to expose the high core material, the low core material, and the support column, and a separator is fixed to the exposed high core material, the low core material, and the support column. A formwork installation process for attaching a formwork for a concrete underground wall;
A method for constructing retaining walls. In the core material embedding step, the temporary core material is detachably attached to the head portion of the low core material, and the struts arranged along the temporary core material are fixed to the head portion of the low core material, and the temporary core material and the struts are After dropping into the wall-like ground improvement body together with the low core material, the temporary core material is removed from the head of the low core material and pulled up.
The construction method of the retaining wall of Claim 2. In the core material burying step, the pair of struts are arranged symmetrically with respect to the center of the temporary core material in plan view.
The construction method of the retaining wall of Claim 3.

Images