JPH04185816A - Construction of beam in underground wall - Google Patents

Abstract

PURPOSE:To completely prevent the inclination of underground wall toward excavated side by earth pressures by a method in which concrete is placed onto fitted reinforcing bars, wall girder reinforcing bars, and frame beam reinforcing bits to fix the wall girder and frame beams to steel tubular piles. CONSTITUTION:Soil cements 6 and 9 are removed from the upper ends of all the steel tubular piles 4 in both-side underground walls 1 and 2 and terminal underground wall and all the steel tubular piles 8 in the intermediate portion to form an adequate depth of spaces 10 and 11. Fitting reinforcing bars 13 and 14 are inserted into the spaces 10 and 11 by projecting their upper ends upwards. The main bars of wall girder reinforcing bars 15 and frame beam reinforcing bars 16 which are assembled on site are welded to the main bars of the reinforcing bars 13 and 14 to connect the bars 13, 14, 15, and 16 together. A formwork is set around the bars 15 and 16 and concrete is placed. After the concrete hardens, excavation is made to form an underground space for an underground structure. An underground structure can thus be on schedule allowed to proceed on schedule while keeping underground walls intact.

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD OF THE INVENTION The present invention relates to a method of constructing a beam in an underground wall, and more particularly to a method of constructing a beam in an underground wall consisting of a row of steel pipe piles stacked against each other. [Conventional technology] When excavating the ground to construct underground structures,
It is a widely known technique to install retaining walls underground before excavating in order to prevent the ground from collapsing. It is often used not only as a temporary retaining wall to ensure safety, but also as part of the outer wall of underground structures. In addition, in order to install such an underground wall without making noise or vibration, for example, cement milk is injected while drilling a hole at a specified depth in the ground using an earth auger excavator, and mixed with the excavated soil to create soil cement. There is a known construction method in which the process of building piles, pulling out an excavator, and inserting piles in adjacent piles is repeated in sequence. H-beam steel, steel pipes, etc. are used as piles, but steel pipes are advantageous because they have high strength and also work as part of the pile because they are filled with soil cement (Japanese Patent Publication No. 58-3091) , see Japanese Patent Publication No. 2-5203). In other words, steel pipes are joined to each other by engaging the joints on the outer circumferential surface and are surrounded by soil cement to form an underground wall, but steel pipes that are joined only by joints are not connected to each other. Due to the lack of force, when the ground is excavated to the required depth and the root cutting is performed, if unplanned pressure is added to the soil pressure, such as when a heavy object is placed on the surrounding nearby ground, a part of the underground wall may be damaged towards the root cutting side. There is a worry that it will tilt. In addition, in order to use such an underground wall as part of the outer wall of an underground structure, wall reinforcing bars and column reinforcing bars are attached to steel pipe piles, and concrete is poured to a specified thickness to form an underground outer wall with integral columns. Japanese Patent Publication No. 2-5203 discloses that the above-mentioned Japanese Patent Publication No. 2-5203 discloses that the reinforcing bars are installed and the concrete is poured into the underground wall exposed by root cutting.
During this period, it is necessary to support the underground wall from the root cutting side so that it does not tilt. In other words, this support means is to pass arm members such as H-beams so that the underground walls facing each other receive each other's forces. Not only is it extremely troublesome to have to remove them one by one, but it is also not perfect because it is impossible to prevent the slope from occurring immediately after cutting the roots before installing supports. Moreover, if a part of the underground wall is tilted, it is not preferable because it becomes a hindrance to using it as a part of the outer wall. [Problem to be Solved by the Invention] The problem to be solved by the present invention is to maintain the underground wall in the state at the time of construction, to proceed with root cutting and the construction of the underground structure as planned, and to complete it as designed. The point is that there was no means of support. [Means for Solving the Problems J] In order to solve the above-mentioned problems, the present invention comprises a plurality of rows of underground walls made up of rows of steel pipe piles filled with soil cement and joined to each other at predetermined intervals; Before cutting the roots in the area between the piles, the soil cement filling the upper end of the steel pipe pile is removed, and mounting reinforcing bars are inserted and installed, and the girder reinforcing bars extending in the longitudinal direction above the underground wall are installed. At the same time, install reinforcing bars extending in the cross direction of the underground wall and connect them to the mounting reinforcing bars, and then pour concrete around the mounting reinforcing bars, girder reinforcing bars, and bridge reinforcing bars to connect them to each other. We took the step of solidifying the girder and the bridge into a single piece of steel pipe pile. For example, an underground wall is made by making soil cement by drilling a hole in the ground using an earth auger excavator, injecting cement milk from the tip of the hole, and mixing it with the excavated soil. In other words, when the excavation progresses until the support layer is reached, the excavator is pulled out of the hole and a steel pipe pile is inserted.Next, a hole filled with soil cement is again formed adjacent to this hole, and the steel pipe pile is inserted into the previous steel pipe. It is constructed by repeating the process of joining and inserting the piles. The steel pipe pile has a joint extending in the axial direction on the outer circumferential surface, and the joints of adjacent steel pipe piles mesh and engage with each other. It is designed to create an underground wall consisting of a substantially continuous row of steel pipe piles that are mechanically connected. In addition, this steel pipe pile is inserted into a hole until it reaches the support layer, and is filled with soil cement that acts as part of the pile. Preferably, the force is increased. Furthermore, cement mortar may be injected into the joints of steel pipe piles to improve water-blocking properties, and the underground walls to which the present invention is applied may be constructed by the construction method disclosed in Japanese Patent Publication No. 58-3091, for example. be done. Next, in the present invention, underground walls are arranged in multiple rows at appropriate intervals, generally on two sides, and the part between them becomes an underground structure such as an underground railway, an underground road, an underground parking lot, a public ditch, or a basement. This is applied in cases where construction is carried out before the construction of these underground structures begins. In other words, the steel pipe piles that make up the underground wall are inserted into the holes so that their upper end surfaces are almost flush with the ground surface, so the beam construction work can be done as is or if necessary, the ground surface on the root cutting side. To make it easier, excavate shallowly and remove the soil cement that is filling the upper end of the steel pipe pile. Note that soil cement is extremely brittle even after hardening, so it can be easily taken out and removed by hand. In principle, soil cement should be removed from all steel pipe piles, but it may not be necessary to remove soil cement from all piles, for example -
There may be no problem even if the removal is performed every other book, and normally it is sufficient to remove only a depth of about 1 to 5 m from the upper end surface. A required number of mounting reinforcing bars consisting of main bars and hoop bars are inserted into the voids of the steel pipe pile thus formed, with their upper ends protruding upward. In addition, girder reinforcing bars consisting of the required number of main bars and hoop reinforcing bars can be prepared in advance or assembled on-site so that they intersect with the upper end of the installation reinforcing bars and are placed along the upper end surface of the underground wall in the longitudinal direction. The main reinforcements are connected by welding to each other. Before or after this work, or in parallel with this work, is it necessary to prepare in advance the required number of bridge reinforcing bars consisting of main bars and hoop bars above the area where the plates are planned to be cut in the cross direction of the underground wall, generally in the right angle direction? Alternatively, it can be assembled on-site and its both ends connected to the mounting reinforcing bars by welding the main bars together. However, for convenience of work, sometimes the girder reinforcing bars and the bridge reinforcing bars are welded to each other, and one is indirectly connected to the attachment reinforcing bars via the other. It goes without saying that the bridge reinforcing bars are placed above the underground walls at predetermined intervals. When the necessary reinforcement has been arranged as described above, formwork is set up surrounding them, concrete is poured into the hollow spaces of the steel pipe piles and into the formwork, and concrete is placed over the upper end of the underground wall or slightly above it, along its length. A girder extending in the direction and a girder installed between the girders on the opposing underground wall are constructed. The girder and the bridge are integral with each other, and the girder is integrated with the mounting leg made of reinforced concrete formed in the hollow space of the steel pipe pile, so the girder and the bridge are fixed to the steel pipe pile. becomes. When a beam consisting of a girder and a bridge beam is constructed in this manner, the portion between the underground walls is excavated to a required depth and roots are cut to construct an underground structure. In addition, if the distance between the underground walls is large, the span of the bridge will also be long, but in this case, if necessary, one or several steel pipe piles may be buried in the middle using the same method as described above to extend the middle part of the bridge. It can be a supporting pillar.

[Action J] A girder installed on an underground wall in the longitudinal direction and a girder installed on the girder on the opposite underground wall are hollow spaces in steel pipe piles, reinforcing bars connected to each other, and surrounding girders. It is integrated with the steel pipe pile by concrete. The girder integrates the rows of steel pipe piles that make up the underground wall, and the girder acts to mutually absorb the forces such as earth pressure acting on the opposing underground walls.
These prevent the underground wall from tilting toward the root cutting side. In addition, this beam is used as a part of an underground structure when an above-ground structure is constructed on top of it. EXAMPLES The present invention will be described in detail with reference to the drawings. Figure 1.2 shows an example of the arrangement of underground walls.
2 and an underground wall 3 constructed at the end are shown. A large number of steel pipe piles 4 are inserted into holes 53 in the ground 51 with their lower ends supported by a support layer 52, as shown in the aforementioned Japanese Patent Publication No. 58-3091 and Japanese Patent Publication No. 2-5203. They are mechanically connected to each other by joints 5 that mesh with each other, and are filled with soil cement 6, and a cover plate 7 having an inflow hole for soil cement 6 at the lower end of the steel pipe pile 4. is provided. Incidentally, since the underground wall 1.2.3 is constructed by a known method such as that described above, its details will be omitted. In addition, steel pipe piles 8 are inserted into the ground 51 at appropriate intervals in the middle of the underground walls 1.2 on both sides in a direction parallel to these, up to the support layer 52, and filled with soil cement 9. Next, as shown in FIG. 3, underground walls 1.2 on both sides and underground terminals (not shown)! ! The soil cement 6.9 filling the upper end portions of all the steel pipe piles 4 in No. 3 and all the intermediate steel pipe piles 8 is removed to form voids 10.11 of an appropriate depth. Further, in parallel with this work, or before and after this, the ground surface on the root cutting side is shallowly excavated to form a foot scene 54. In the vacant space 10.11, as shown in FIG.
3.14 are inserted and deployed with their upper ends protruding upward. In addition, as shown in FIG. 5, girder reinforcing bars 15 and bridge reinforcing bars 16 consisting of the required number of main reinforcing bars and hoop bars are assembled on site, and these main reinforcing bars are welded to the main reinforcing bars of the mounting reinforcing bars 13 and 14. By each reinforcing bar 13.14.15.1
6 to each other. That is, girder reinforcing bars 15 are placed in the longitudinal direction along the upper end surfaces of underground walls 1.2.3, and girder reinforcing bars are placed in a direction perpendicular to underground wall 111.2 passing over intermediate steel pipe piles 8. 16, and when the necessary reinforcement is completed, formwork is installed surrounding the girder reinforcing bars 15 and bridge reinforcing bars 16, and concrete 17 is poured into the void space 10.11 and the formwork. Set up As a result, the 6.7th rj! As shown in J, a girder 18 that overlaps the upper end surface of the underground wall 1.2.3 and extends in the longitudinal direction thereof, and a frame constructed between the girder 18 on the opposing underground wall 1.2. A beam 19 is constructed, and a mounting leg 20.21 is constructed which fills the void 10.11. These are integral with each other, and the girder 18 and the bridge 1
Reference numeral 9 denotes a mounting leg at the upper end of the underground wall 1.2.3, which is fixed to the steel pipe pile 4 by means of a mounting leg 20, and the bridge beam 19 is fixed to the steel pipe pile 8 by a mounting leg 21 at the center. When the beam is constructed as described above, the roots are cut after waiting for the concrete to harden to create an underground space 55 of a predetermined depth for constructing an underground structure, and the underground wall 1.2.3 is an outer wall. The middle steel pipe pile 8 is used as a part of the column. In addition, the stand @ 17 and the bridge 18 will be used for the underground structure as well as a part of the above ground structure. [Effects of the Invention] According to the present invention, prior to root cutting, the upper end surface of the steel pipe pile constituting the underground wall is exposed to the ground surface to create a slope extending in the longitudinal direction of the underground wall. Since the beam and the bridge extending in the cross direction are fixed to the steel pipe piles, the construction work of the beam can be done on the ground surface and is extremely easy. Then, the steel pipe piles of the underground wall are continuously integrated using these girders and bridge beams, and the roots are cut after the forces acting on the opposing underground walls are mutually received. It is completely prevented from tilting towards the cutting side, and -
Root cutting work can be carried out safely without the need for temporary support. Therefore, it is possible to maintain the underground walls in the state they were in when they were constructed, and proceed with root cutting and construction of the underground structure as planned and complete it as designed.
Furthermore, it can also be used economically as a part of above-ground structures.

[Brief explanation of the drawing]

Figures 1 and 2 are a vertical cross-sectional view and a partial plan view of an example of an underground wall, No. 3 IjlJ is a partial vertical cross-sectional view with soil cement removed, and Figure 4 is a vertical cross-section with installation reinforcing bars installed. Figure 5 is a partial plan view with girder reinforcing bars and bridge reinforcing bars in place, and Figures 6 and 7 are a vertical cross-sectional partial view and a partial plan view with concrete poured.
．． 2... Underground wall, 4... Steel pipe pile, 6... Soil cement, 10... Vacant space, 13... Mounting reinforcing bar, 15.
・・Bottom beam reinforcing bar, 16... Bridge reinforcing bar, 17... Concrete, 18... Beam beam, 19... Bridge beam, 2o...
Mounting legs, Figure 3, Figure 4, Figure 5, Figure 6, Figure 1

Claims (1)

[Claims] A subterranean wall consisting of rows of steel pipe piles filled with soil cement and joined to each other is constructed at predetermined intervals, and the upper end portions of the steel pipe piles are filled with soil cement before root cutting is performed between the rows of the steel pipe piles. removing the soil cement that is attached to the underground wall, inserting and installing mounting reinforcing bars, and placing girder reinforcing bars extending in the longitudinal direction above the underground wall, and providing bridge reinforcing bars extending in the cross direction of the underground wall. These are connected to the mounting reinforcing bars, and then concrete is poured around the mounting reinforcing bars, the girder reinforcing bars, and the bridge reinforcing bars, thereby solidifying the girder and the bridge as one unit to the steel pipe pile. A method of constructing beams in underground walls, characterized by: