JPH06116942A - Construction method of critical sheathing wall - Google Patents

Abstract

PURPOSE:To easily construct a critical sheathing wall by placing a bottom concrete on the bottom of a trench, arranging L-shaped precast members in the trench widthwise to backfill the rear side of a vertical wall board of the precast members. CONSTITUTION:A precast concrete vertical wall board 3 and a precast concrete floor board 4 are connected with a screw bar 6 and, at the same time, a temporary support 10 is installed across them to form L-shaped concrete precast members 5. After the ground is excavated slightly deeper than an excavated bottom to form a trench, a bottom concrete 2 is placed on the bottom of the trench. The members 5 are arranged to the inside of the trench, and a part of a shear-key 8 is inserted into the bottom concrete 2. In addition, backfilling 11 is made to the rear side of the vertical wall board 3 with sand.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-standing mountain retaining wall suitable for constructing a structure of the first basement floor by excavating various types of underground structures, particularly the basement part of a building, especially about 4 to 5 m. It is about the construction method of.

[0002]

2. Description of the Related Art In the construction of underground structures, a temporary earth retaining wall (mounting wall) is usually constructed where excavation is desired, root cutting is performed to the floor attachment position, and discarded concrete, underground slabs, etc. are successively installed. Build it. Then, conventionally, as the formation of this earth retaining wall, parent piles such as H-section steel are placed on the center line of the planned mountain retaining wall at intervals of about 1 m to 2 m,
A typical method is a parent pile side sheet pile method that is constructed by fitting a side sheet pile as the excavation progresses.

In addition to the parent pile side sheet pile system, a steel sheet pile or steel pipe sheet pile system in which sheet piles, steel pipes, and other sheet piles are continuously struck one by one to form a water retaining wall.
There is also a column-column pile method in which cast-in-place concrete (including soil concrete) is continuously cast to form a retaining wall.

[0004]

The above-mentioned horizontal pile pile method for parent piles can relatively economically form the earth retaining wall and can be applied to hard ground where steel sheet piles cannot be placed, but since it does not have water stopping ability. It is not suitable for the ground with a lot of groundwater, and overburden is likely to occur when inserting the horizontal sheet pile, and the surrounding ground is likely to move or sink, and the heaving phenomenon is likely to occur. . Since there are many types of steel sheet piles or steel pipe sheet pile methods, it is possible to use those having a cross section that meets the usage conditions, but the initial cost may be high, and hard ground such as gravel layers cannot be punched. Further, since the rigidity of the sheet pile is not so high, the driving length is limited.

Since the column-row pile method has less deflection, the back soil does not move and the surrounding ground is less affected. In addition, although the strength dimension can be constructed, the construction period is long,
The construction cost is also increased. Furthermore, in any of the above methods, when the self-supporting earth retaining structure is used, a large excavating machine for constructing the mountain retaining wall is required, and if necessary, a heavy temporary material such as a steel sill must be attached.

The object of the present invention is to eliminate the disadvantages of the above-mentioned conventional example, to eliminate the need for shavings, anchors, etc. in the construction of underground structures, and to carry out the construction easily and in a short time without using large heavy equipment. The L-shaped concrete precast member to be used can be combined with the precast concrete floorboard under the precast concrete floorboard at the site. Since the whole is assembled into an L-shape or a substantially L-shape, it is an object of the invention to provide a method for constructing a self-supporting mountain retaining wall that can be easily carried in a flat plate state when being carried into the field.

[0007]

In order to achieve the above-mentioned object, the present invention arranges a bottom concrete at the bottom of a trench excavated with an appropriate width and an appropriate length, and at the bottom of a precast concrete vertical wall board, a conventional A precast concrete floorboard or a precast concrete floorboard whose lower surface is inclined is combined so that the inclination direction is lowered toward the precast concrete vertical wallboard side to assemble a substantially L-shaped concrete precast member, and this substantially L-shaped concrete precast member Are arranged side by side in the groove, and the back side of the precast concrete vertical wall board is backfilled, and the precast concrete horizontal floorboard projects a screw rod from the end, and this screw rod is used for the precast concrete vertical wallboard. L-shaped by inserting it into the bolt hole provided in the Assembling the concrete precast member, further, the precast concrete vertical wall board has the lower end protruding downwardly from the precast concrete horizontal floor board, and this sherky portion is inserted into the bottom concrete, or with an appropriate width and an appropriate length. The bottom concrete is placed on the bottom of the excavated trench, and the lower part of the precast concrete vertical wall board is joined to the precast concrete floor board whose lower surface is inclined so that the inclination direction is lowered to the precast concrete vertical wall board side, and the whole is approximately L. Assemble a concrete precast member in the shape of a letter, and make this substantially L-shaped concrete precast member have an appropriate width,
Further, the gist of the present invention is to arrange them side by side in trenches excavated to an appropriate length and to backfill the periphery of the precast concrete vertical wall plate.

[0008]

According to the present invention as set forth in claim 1, the groove can be excavated by a backhoe excavator, and the bottom concrete is arranged in the groove, and further the substantially L-shaped concrete assembled on site. The mountain retaining wall can be constructed only by appropriately disposing the precast member in the groove and backfilling the back side.

Then, the bearing force of the earth pressure flooring ground at that time can be determined by the cross-sectional area of the L-shaped precast member. Also, earth pressure can be counteracted by the lower surface supporting force of the horizontal portion of the precast member. In this way, no burrs are needed, and since the wall surface is a precast member, it can be used as it is for main installation without finishing.

According to the fourth aspect of the present invention, in addition to the above action, the lower surface of the precast concrete floor board is inclined so that the inclination direction is lowered toward the precast concrete vertical wall board side. By applying it, the reaction force that resists earth pressure effectively acts on this part, and it becomes more effective.

According to the second and fifth aspects of the present invention, in addition to the above-described action, the L-shaped or substantially L-shaped precast member can be easily assembled on site.

According to the present invention as set forth in claims 3 and 6, in addition to the above-mentioned action, by inserting the lower end of the precast concrete horizontal floorboard into the bottom concrete as a shear key, the pull-out resistance of this shear key
It will be able to further resist earth pressure.

According to the present invention as set forth in claim 7, since the upper part of the precast concrete floorboard is mainly backfilled, if the site has a margin, the outer wall of the underground and the pillar can be freely connected.

Further, the mechanical balance is similar to that of the fourth aspect, but as in the fourth aspect, the pull-out force generated by the frontward falling of the head portion of the precast concrete vertical wall plate is applied to the anchor of the shear key portion. Instead of dealing with pile action, we deal with the weight of backfilled soil,
The method is simple in construction method.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a side view showing a first embodiment of a method for constructing a self-supporting mountain retaining wall of the present invention. In FIG. 1, 1 is a backhoe excavator as shown in FIG.
And it is a groove that is excavated to a certain depth and slightly deeper than the root cutting bottom.

As an example, the groove 1 has a width of 1 to 1.5 m, a length of 2 to 3 m, and a height of 4 to 5 m, and is 30 to 30 mm from the root cutting bottom described later.
It is a digging deep about 50 cm.

Next, as shown in FIG. 3, a bottom concrete 2 is arranged on the bottom of the groove 1.

On the other hand, the precast concrete vertical wall board 3 and the precast concrete floor board 4 produced in the precon factory are carried into the site. As shown in FIG. 4, the precast concrete floorboard 4 is provided with a screw rod 6 protruding from the end thereof, and the precast concrete vertical wallboard 3 is formed with a bolt hole 7 in the thickness direction at the lower portion thereof. The tip of the bolt hole 7 is tapered in the cross-sectional direction below the bolt hole 7,
This portion was constructed as a shear key 8.

The screw rod 6 is inserted into the bolt hole 7 and fixed with a nut, and the precast concrete floorboard 4 is joined to the lower part of the precast concrete vertical wall board 3 to form an L-shaped concrete precast member 5 as shown in FIG. Assemble. In addition, the precast concrete vertical wall board 3 and the precast concrete floor board 4 include the floor board 4
A brace-shaped temporary support 10 is hung over above.

At the joint between the precast concrete vertical wall board 3 and the precast concrete floor board 4, a waterproof seal made of butyl rubber, water-swelling synthetic resin or the like is provided to improve the waterproof performance, or an epoxy resin is adhered. An agent can be applied to increase the strength. The inner surfaces of the vertical wall plate 3 and the floor plate 4 are protected by attaching a vinyl sheet or the like so that they can be directly used as they are later.

The L-shaped concrete precast members 5 are arranged side by side in the groove 1, but if this is done in a state where the bottom concrete 2 is not completely hardened, the portion of the shear key 8 will become the bottom concrete 2. Can be inserted inside.

Then, the concrete precast member 5
The joints between the left and right sides are waterproof joints 9 (see FIG. 6) for repair and waterproof with mortar or the like, and as shown in FIG. 1, backfilling 11 with sand is applied to the back side of the precast concrete vertical wall board 3.

If one or several L-shaped concrete precast members 5 are thus arranged in the groove 1, the above-mentioned excavation step is performed again, and the excavation step of the groove 1 and the concrete precast member 5 are performed. Repeat the placement process as appropriate. As a result, a large number of concrete precast members 5 are continuously arranged in the continuous groove 1.

As shown in FIG. 6, root cutting is performed on the inside of the continuous body of the concrete precast member 5, and a rubble stone and abandoned concrete 12 are horizontally attached to the floor of the root cutting floor. It is laid with the same thickness as the floor plate 4. Also, remove the vinyl sheet for surface protection.

Then, by arranging the bar and placing the mat concrete and constructing the underground concrete slab 13 on the floor board 4 and the discarded concrete 12 or the crushed stone, the concrete precast member 5 and the underground concrete slab 13 are integrated. Turn into. After that, the structure is constructed by the conventional method.

In this way, the support mechanism of the earth retaining frame against earth pressure after the root cutting is as shown in FIG. 7, but the concrete precast precast member 5
With the pulling resistance of the shear key 8 and the lower surface supporting force of the precast concrete floor plate 4, it is possible to counter the earth pressure. Therefore,
If the magnitude of earth pressure and the bearing capacity of the ground with floor are determined, the cross section of the concrete precast member 5 can be designed accordingly.

When the pull-out force is insufficient with only the shear key 8, a steel material such as H-shaped steel is put on the front side of the precast concrete vertical wall board 3 and the tip thereof is projected largely downward so that long legs are formed. It may be configured.

FIG. 8 shows a second embodiment of the present invention.
The lower surface of the precast concrete floorboard 4 is an inclined surface 4a, and the precast concrete floorboard 4 is combined with the precast concrete vertical wallboard 3 so that the inclination direction of the inclined surface 4a is lowered toward the precast concrete vertical wallboard 3 side. A concrete precast member 5'having a substantially L-shape as a whole is assembled.

The precast concrete floor board 4 having an inclined lower surface preferably has a horizontal surface on the upper surface and a taper with a large thickness at the base end as shown in the figure, but a plate having a uniform thickness may be provided obliquely. .

The other structure is the same as that of the first embodiment,
The precast concrete floorboard 4 is provided with a screw rod 6 projecting from the end thereof, and the precast concrete vertical wallboard 3 has a bolt hole 7 formed in the lower portion thereof in the thickness direction. Also,
Below the bolt hole 7, the tip is tapered in the cross-sectional direction, and this portion is formed as a shear key 8.

The screw rod 6 is inserted into the bolt hole 7 and fixed with a nut, and the precast concrete floor plate 4 is joined to the lower portion of the precast concrete vertical wall plate 3 to assemble a substantially L-shaped concrete precast member 5 '.

In this case, since there is the inclined surface 4a, the reaction force that resists the earth pressure effectively acts on this portion,
It will be more effective. That is, as shown in FIGS. 9 and 10, there is a passive earth pressure (b) that effectively resists the active earth pressure (a).

In particular, in the case of clay ground having no internal friction angle δ, the pull-out resistance of the shear key 8 at the lower end of the precast concrete vertical wall plate 3 may be insufficient, which is effective.

In this embodiment, in the case of sandy soil, the horizontal component of the passive soil pressure (b) (bearing force of the precast concrete floorboard 4) increases due to the internal friction angle of the sand, and the horizontal reaction force increases. . In other words, a slight displacement of the wall of the mountain retention due to the active earth pressure (a) will generate a passive earth pressure (b) on the floor.

Also in this embodiment, if the pulling force is insufficient with only the shear key 8, a steel material 14 such as H-section steel may be inserted below the precast concrete vertical wall plate 3.

FIG. 11 shows a third embodiment of the present invention.
A precast concrete floorboard 4 having an inclined lower surface is joined to a lower portion of the precast concrete vertical wallboard 3 so that the inclination direction is lowered toward the precast concrete vertical wall board 3 to assemble a concrete precast member 5'having a substantially L shape as a whole. The substantially L-shaped concrete precast member 5'is arranged side by side in a groove excavated with an appropriate width and an appropriate length as in the second embodiment, but not only on the back surface but also on the precast concrete. Floor board 4
The surroundings of the precast concrete vertical wall plate 3 including the upper part of the above were refilled.

In this way, first, if the site has a lot of space, the connection between the underground outer wall and the pillar becomes free.

Further, the mechanical balance is very similar to that of the second embodiment, but as in the second embodiment, the pulling-out force generated by the frontward falling of the head of the precast concrete vertical wall plate 3 as in the second embodiment. Rather than dealing with the anchor pile action of the shear key 8 part, as shown in Fig. 12 and Fig. 13, the sum W of the weight of backfill soil and the weight of concrete W
Since it will be dealt with, it will be simple in terms of construction method.

If the ground is soft and the supporting force (passive earth pressure) is insufficient at the underfloor position, the ground may be improved or
As shown in FIG. 5, H steel piles 15 or the like may be cast as necessary to firmly bond to the precast concrete vertical wall board 3.

[0040]

As described above, the method for constructing a self-supporting mountain retaining wall according to the present invention does not require cuts, anchors or the like to construct an underground structure, and does not require the use of large heavy equipment. It's easy and quick to install, and highly reliable.
Moreover, the Yamadome wall can also be used as a permanent underground outer wall.

The L-shaped concrete precast member to be used is L-shaped by connecting the precast concrete floor board to the lower part of the precast concrete vertical wall board on site.
Since it is assembled in a letter shape, it can be easily carried in the flat state when it is carried into the site.

Further, the strength of the concrete precast member itself, the length, etc. can cope with the ground strength and the excavation depth, and the reliability is high. If you put it back,
It is also possible to widely use the site.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of a method for constructing a self-supporting mountain retaining wall of the present invention.

FIG. 2 is a perspective view showing a first step of the first embodiment of the method for constructing a self-supporting mountain retaining wall of the present invention.

FIG. 3 is a perspective view showing a second step of the first embodiment of the method for constructing a self-supporting mountain retaining wall of the present invention.

FIG. 4 is a perspective view before assembling of a concrete precast member used in the method for constructing a self-supporting mountain retaining wall of the present invention.

FIG. 5 is a perspective view after assembling of a concrete precast member used in the method for constructing a self-supporting mountain retaining wall of the present invention.

FIG. 6 is a perspective view showing construction of an underground structure using a mountain retaining wall in the method for constructing an independent mountain retaining wall of the present invention.

FIG. 7 is an explanatory view showing a support mechanism of the first embodiment.

FIG. 8 is a side view showing a second embodiment of the method for constructing a self-supporting mountain retaining wall of the present invention.

FIG. 9 is an explanatory view showing a support mechanism of the second embodiment.

FIG. 10 is a vector diagram of the support mechanism of the second embodiment.

FIG. 11 is a side view showing a third embodiment of the method for constructing a self-supporting mountain retaining wall of the present invention.

FIG. 12 is an explanatory view showing a support mechanism of the third embodiment.

FIG. 13 is a vector diagram of a support mechanism of the third embodiment.

[Explanation of symbols]

1 ... Groove 2 ... Bottom concrete 3 ... Precast concrete vertical wall board 4 ... Precast concrete horizontal floor board 4a ... Inclined surface 5, 5 '... L-shaped concrete precast member 6 ... Screw rod 7 ... Bolt hole 8 ... Shear key 9 ... Waterproof joint 10… Temporary support 11… Backfilling 12… Waste concrete 13… Underground concrete slab 14… Steel 15… H steel pile

Claims (7)

[Claims] 1. A concrete precast member having an L-shape as a whole is provided by arranging a bottom concrete on a groove bottom excavated with an appropriate width and an appropriate length, and connecting a precast concrete floor board to a lower portion of a precast concrete vertical wall board. A method for constructing a self-supporting mountain retaining wall, characterized by assembling, arranging the L-shaped concrete precast members side by side in the groove, and backfilling the back side of the precast concrete vertical wall plate. 2. An L-shaped concrete precast member is assembled by projecting a screw rod from an end of the precast concrete floorboard, and inserting the screw rod into a bolt hole provided in the precast concrete vertical wall plate to fix the nut with a nut. Item 1. The method for constructing a self-supporting Yamadome wall according to item 1. 3. The self-supporting mountain according to claim 1 or 2, wherein the precast concrete vertical wall board is constructed as a shear key by projecting the lower and end portions downward of the precast concrete floor board, and this shear key portion is inserted into the bottom concrete. Construction method of retaining wall. 4. A precast concrete floorboard, in which a bottom concrete is arranged at the bottom of a trench excavated with an appropriate width and an appropriate length, and a lower surface of the precast concrete vertical wallboard has a lower surface inclined. Assemble the concrete precast members that are substantially L-shaped by connecting so as to hang down to the plate side, and arrange the substantially L-shaped concrete precast members side by side in the groove, and the rear side of the precast concrete vertical wall plate. A method of constructing a self-supporting Yamadome wall characterized by backfilling. 5. The precast concrete floorboard has a screw rod protruding from the end of the root portion, and the screw rod is inserted into a bolt hole provided in the precast concrete vertical wall plate and is nut-fixed, so that the entire precast concrete floorboard is substantially L-shaped. The method for constructing a self-supporting Yamadome wall according to claim 4, wherein the members are assembled. 6. The precast concrete vertical wallboard comprises:
The method for constructing a self-supporting mountain retaining wall according to claim 4 or 5, wherein the lower end portion is projected downward of the precast concrete floorboard to form a shearkey, and the shearkey portion is inserted into the bottom concrete. 7. A precast concrete floorboard, in which a bottom concrete is disposed on a groove bottom excavated with an appropriate width and an appropriate length, and a lower surface of the precast concrete vertical wallboard is inclined at a lower surface thereof. Assemble a concrete precast member that is substantially L-shaped as a whole by joining so as to hang down to the plate side, and arrange the substantially L-shaped concrete precast members side by side in a groove excavated with an appropriate width and an appropriate length. , A method for constructing a self-supporting Yamadome wall characterized by backfilling the surroundings of a precast concrete vertical wallboard.