JP6994401B2 - Yamadome construction method - Google Patents

Description

The present invention relates to a Yamadome construction method.

When constructing a mountain reservoir in a sandy mountain, it is common to use SMW (Soil Mixing Wall), sheet pile, etc. to prevent the collapse of the sandy mountain and the outflow of sand from the mountain retaining wall. Since these construction methods have a problem of high cost, the parent pile horizontal sheet pile method is often used as a cost-reducable mountain retaining method (mountain retaining construction method) (see, for example, Patent Document 1).

In the general method of constructing a mountain retaining pile with a horizontal sheet pile (hereinafter referred to as "parent pile horizontal sheet pile method"), a parent pile made of H-shaped steel is placed in the ground and then the ground is excavated. At the time of excavation, in order to secure a space for inserting the horizontal sheet pile between the main piles, excavate by biting into the inside (the ground (back soil) side on the non-excavation side) slightly inside the flange surface of the main piles. After that, the sheet piles are stacked tightly between the main piles, and the gap between the sheet piles and the ground on the back side of the horizontal sheet piles is filled with the backfill material (soil, residual soil). When it is necessary to excavate deep underground, the work of performing primary excavation and installing a horizontal sheet pile, then performing secondary excavation and installing a horizontal sheet pile at a deeper position is repeated.

Special Fair 6-99908 Gazette

By the way, in the parent pile horizontal sheet pile method disclosed in Patent Document 1, there is no problem because the normal ground is soil, but in the case of sand dunes (sand dunes, etc.), it cannot stand on its own, and as shown in FIG. 9, the parent pile 101 is used. When the sand dune 109 was excavated after the installation, there was a problem that the sand collapsed even on a shallow slope and the horizontal sheet pile could not be inserted.

In addition, if sand pits can be excavated and a horizontal sheet pile is installed between H-shaped steels, if residual sand is put on the back side of the horizontal sheet pile as a backfill material, it will be excavated even deeper (that is, secondary excavation). When installing the horizontal sheet pile, there was a problem that the sand of the backfilling material that was put in earlier collapsed and flowed into the lower part, making it impossible to insert the horizontal sheet pile. There is also the problem that sand flows out from the gaps in the horizontal sheet pile when it rains.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technique that can be appropriately constructed when the parent pile horizontal sheet pile method is applied to a soil-like ground such as a sandy mountain. do.

The present invention is a method for constructing a mountain retaining pile using a horizontal sheet pile of a parent pile, in which a parent pile driving step of driving a plurality of parent piles into a ground at intervals and water solubility in the ground between the parent piles. After the adhesive infiltration step of infiltrating the adhesive and solidifying the ground and the solidification of the ground infiltrated with the water-soluble adhesive, the ground is excavated and a horizontal sheet pile is placed between the parent piles. Including the horizontal sheet pile insertion process to be inserted,
It is characterized in that the water-soluble adhesive is infiltrated from the ground surface around the parent pile in the depth direction at least to a depth at which a space for inserting the horizontal sheet pile is secured .
In the construction of a retaining pile in a sandy mountain or the like, when excavating the ground between the parent piles, the ground solidified by the water-soluble adhesive is excavated, so that the collapse of the excavated part can be suppressed / prevented. In addition, workability is improved because the ground is stable.

Further, as the water-soluble adhesive, for example, there are ethylene-vinyl acetate copolymer emulsion of industrial origin agent, glue of natural origin agent, gelatin and the like. Since the water-soluble adhesive can be easily diluted with water, it can be adjusted according to the construction conditions (soil quality of the ground, climate, working time, etc.).

Further, in the case of industrially derived agents, there are various types having characteristics such as water resistance, chemical resistance, weather resistance, storage stability and the like, and they can be selected according to the construction conditions. In the case of a naturally derived agent, since it is biodegradable, it is particularly suitable when consideration for the environment is required.

Further, the adhesive permeation step for permeating the water-soluble adhesive may be carried out at any step before and after the parent pile driving step. The method of carrying out the adhesive permeation step before is effective when the ground is loose and the workability at the construction site is also taken into consideration. In the method of carrying out the adhesive permeation step later, the water-soluble adhesive can be permeated intensively and efficiently in the portion where the collapse is likely to occur due to excavation.

The gap between the horizontal sheet pile and the excavated wall surface may be filled with a backfill material filling step in which sand and cement are mixed and air-kneaded mortar is filled as a backfill material.
The excavated wall surface can be stabilized by performing the backfill material filling process. That is, by kneading sand and cement as a backfill material without containing water, the state becomes light and smooth, so that filling is easy and compaction is not required.

The adhesive permeation step may include a first adhesive permeation step performed before the parent pile driving step and a second adhesive permeation step performed after the parent pile driving step.
When the ground is soft, a water-soluble adhesive that is lightly solidified with a thin water-soluble adhesive in the first adhesive infiltration step to ensure workability and prevents collapse due to excavation in the second adhesive infiltration step. It is possible to infiltrate.

According to the present invention, when the parent pile horizontal sheet pile method is applied to a soil-like ground such as a sandy mountain, the water-soluble adhesive is infiltrated in advance into the excavation area between the parent piles to accompany the excavation. We can provide technology that can prevent the collapse of the ground and properly build a pile.

It is a perspective view which shows the construction state of the Yamadome construction method by the parent pile horizontal sheet pile which concerns on embodiment of this invention. It is a figure which enlarges and shows the mountain retaining part constructed by the parent pile horizontal sheet pile which concerns on embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line A of FIG. 2 according to an embodiment of the present invention. It is a perspective view which shows typically the process of spraying a water-soluble adhesive in the region where a parent pile was driven and infiltrating into the ground which concerns on embodiment of this invention. It is a figure which shows the internal state of the ground at the time of permeation of a water-soluble adhesive which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the Yamadome construction method by the parent pile horizontal sheet pile which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the Yamadome construction method by the parent pile horizontal sheet pile which concerns on the modification of embodiment of this invention. It is a flowchart which shows the procedure of the Yamadome construction method by the parent pile horizontal sheet pile which concerns on the modification of embodiment of this invention. It is a perspective view which shows the construction state of the Yamadome construction method by the parent pile horizontal sheet pile which concerns the background technology.

Next, an embodiment for carrying out the present invention (hereinafter, simply referred to as “embodiment”) will be specifically described with reference to the drawings.

FIG. 1 is a perspective view schematically showing a construction state of a mountain retaining construction method using a parent pile horizontal sheet pile. FIG. 2 shows an enlarged view of the mountain retaining portion constructed by the horizontal sheet pile of the main pile. Further, FIG. 3 is a cross-sectional view taken along the line A of FIG. 2. In this embodiment, it is assumed that the ground 9 is formed of coarse-grained sand such as sand dunes. In the case of dunes, fine-grained sand is blown away and large-grained sand does not blow up, so mountains are formed only by relatively coarse (large) sand. Therefore, it is more likely to collapse than a normal sand mountain. Therefore, the water-soluble adhesive 4 is infiltrated into the excavation area to prevent the ground 9 from collapsing due to excavation. Hereinafter, it will be described in detail.

For example, as shown in FIG. 3, in the state where the mountain retaining material is constructed, the horizontal sheet pile 2, the backfill material 6, and the adhesive-penetrated soil 5 are formed in this order from the excavation side to the ground 9 side.

More specifically, as shown in FIGS. 1 and 2, a plurality of main piles 1 made of H-shaped steel are embedded in the ground at regular intervals in the ground 9. At this time, the flange 11 of the main pile 1 is arranged so as to be located on the same straight line. The area where the main pile 1 is driven is the adhesive-penetrated soil 5 in which the water-soluble adhesive 4 is impregnated.

As explained in the background technology, excavation of the ground 9 is performed after embedding the main pile 1, but if the ground 9 is a sandy mountain or the like, if no measures are taken, the ground 9 on the non-excavated side is excavated. Collapse is likely to occur. However, since the adhesive-penetrated soil 5 is formed, the collapse of the ground 9 during excavation is prevented.

The water-soluble adhesive 4 includes, for example, an ethylene-vinyl acetate copolymer emulsion, a naturally-derived agent such as glue, and gelatin in the case of an industrial-derived agent. Since the water-soluble adhesive can be easily diluted with water, it can be easily adjusted according to the construction conditions (soil quality, climate, working time, etc. of the ground 9). Further, in the case of industrially derived agents, there are various types having characteristics such as water resistance, chemical resistance, weather resistance, storage stability and the like, and they can be selected according to the construction conditions. In the case of a naturally derived agent, since it is biodegradable, it is particularly suitable when consideration for the environment is required. As the water-soluble adhesive 4, it has been confirmed that an ethylene-vinyl acetate copolymer emulsion diluted 20-fold with water is used and sprayed on sand dunes to obtain a desired effect.

As shown in FIGS. 4 and 5, the water-soluble adhesive 4 sprayed in the peripheral region of the main pile 1 and penetrated into the ground 9 binds the sand particles 98 to each other. When the ground 9 is a sand dune, the relatively coarse particles 98 are uniform, so that the sprayed water-soluble adhesive 4 permeates in an instant, and the diffusion in the horizontal direction is slight, and it is almost vertical. Penetrate in the direction. That is, it is easy to control the region of the adhesive-penetrated soil 5 to a desired range. Therefore, by infiltrating the water-soluble adhesive 4 into an appropriate area, excavation work can be performed even in the ground 9 such as sand dunes as in the case of other general soil quality. Some adhesives are cement-based, but if there is solid content such as cement, they will not substantially penetrate into the sand pits, and even if they do, it is necessary to stir in order to solidify after penetration. , Workability is significantly reduced. In the present embodiment, by using the water-soluble adhesive 4, it is possible to easily infiltrate the adhesive without stirring, and the workability at the construction site is good.

As shown in FIG. 3, on the back surface side (ground 9 side) of the horizontal sheet pile 2 installed between the main piles 1, the backfill material 6 is placed in the space between the adhesive infiltrated soil 5 and the horizontal sheet pile 2. Is filled. The backfill material 6 is generally filled with residual soil or the like at the time of excavation, but in the present embodiment, it is an air-kneaded mortar in which sand and cement are air-kneaded, and reacts with water in the ground 9 by hydration. Solidify. For example, a backfilling material 6 that has been air-kneaded with sand: cement = about 3: 1 can be used.

The backfill material 6 is in a smooth state that does not contain water at the time of filling, does not require compaction, and has good workability at the construction site. Unlike general mortar filling, there is no need to apply a vibrator to crush the voids after casting, and it does not take several weeks to develop the desired strength and the work is not interrupted. The backfill material 6 is solidified by a hydration reaction due to the moisture in the ground 9, but it has been confirmed that if the ground 9 is in a wet state, it can be excavated in about half a day to a day. ..

As shown in FIG. 3, it is considered that a large number of shrinkage cracks 96 are generated in the backfill material 6. The shrinkage crack 96 divides the lumps into a plurality of lumps, but each lump corresponds only to the compression direction. Even if the lump is divided, it does not fall because it is caught by the unevenness of the ground 9 (adhesive-penetrated soil 5) and adheres to the horizontal sheet pile 2.

As described above, the backfill material 6 can sufficiently withstand practical use as long as it can withstand compression. Further, since the components and water of the water-soluble adhesive 4 are supplied from the adhesive-penetrated soil 5 formed in the adjacent region, those components permeate into the shrinkage crack 96, and the effect of repairing the crack can be expected. Further, since the backfill material 6 is provided, it is possible to prevent sand from flowing out from the gap of the horizontal sheet pile 2 when it rains.

The construction procedure of the Yamadome construction method using the main pile horizontal sheet pile will be briefly described with reference to the flowchart of FIG.

First, as the parent pile driving step (S11), the parent pile 1 is driven into the ground 9 at predetermined intervals by a driving machine at the planned site of the building.

Next, as an adhesive permeation step (S12), as shown in FIG. 4, the water-soluble adhesive 4 is sprayed and permeated into the ground in the peripheral region of the position where the parent pile 1 is driven. It is not necessary to spray so much on the area on the excavation side of the main pile 1 at the time of excavation, but it is preferable to spray it over a wide area on the opposite side (ground 9 side) from the viewpoint of preventing collapse.

Subsequently, as an excavation step (S13), the ground 9 is excavated to a predetermined depth to form a desired excavation surface 92. At the time of excavation, in order to secure a space for inserting the horizontal sheet pile 2, excavation is performed until it enters the ground 9 side (non-excavation side) from the surface of the flange 11 on the excavation side of the main pile 1. As a result, the flange 11 on the excavation side is exposed. As a result, at least a part of the area between the webs 12 connecting the flanges 11 is formed as voids. The surface (back soil) of the ground 9 on the non-excavation side is an adhesive-penetrated soil 5 in which the water-soluble adhesive 4 has penetrated, and excavation is performed so that a part of the adhesive-impregnated soil 5 remains. ..

Next, as the horizontal sheet pile insertion step (S14), the horizontal sheet pile 2 cut to a predetermined size is stacked and set in the gap formed between the main piles 1 (web 12) from below.

Subsequently, as a backfilling material filling step (S15), the backfilling material 6, which is an empty kneading mortar obtained by empty-kneading sand and cement, is filled in the voids formed on the back surface side of the horizontal sheet pile 2. As described above, in the general mortar filling method, compaction is required after filling the mortar. Therefore, when setting the horizontal sheet pile 2, set several sheets from the lower side and then fill the mortar. Furthermore, it was necessary to repeat the work of setting the horizontal sheet pile 2 and filling the mortar. However, since the backfill material 6 is an empty kneading mortar as in the present embodiment, the number of horizontal sheet piles 2 to be set at one time is not limited as in the case of filling the mortar.

As described above, in the mountain retaining construction method of the present embodiment, the water-soluble adhesive 4 is sprayed and permeated around the mountain retaining surface of the ground 9 (that is, the position where the main pile 1 is driven) before excavation. As a result, the ground 9 of the sandy mountain can be solidified before excavation, so that excavation can be prevented from collapsing. If it is necessary to excavate deep underground, the primary excavation is performed, the horizontal sheet pile 2 up to the primary excavation surface 92a is installed, and then the secondary excavation is performed to a deeper position (secondary excavation surface 92b in FIG. 1). ) Repeat the work of installing the horizontal sheet pile 2.

The present invention has been described above based on the embodiments. It is understood by those skilled in the art that this embodiment is an example, and that various modifications are possible in the combination of each of these components, and that such modifications are also within the scope of the present invention. For example, as the backfill material 6, soil or another filler such as mortar (water + sand + cement) may be used. Further, as the soil or sand, the soil or sand excavated locally may be used. Modifications 1 and 2 will be described below.

FIG. 7 is a flowchart of the Yamadome construction method according to the first modification. In the modified example, as the adhesive permeation step (S21), the water-soluble adhesive 4 is sprayed on the area where the main pile 1 is to be driven, and then the main pile 1 is placed at predetermined intervals as the parent pile driving step (S22). I will drive into the ground 9. Subsequently, as an excavation step (S23), the ground 9 is excavated to a predetermined depth, and as a horizontal sheet pile insertion step (S24), a horizontal sheet pile 2 cut to a predetermined size is set. After two sets of horizontal sheet piles, as a backfilling material filling step (S25), the backfilling material 6 which is an empty kneading mortar obtained by empty-kneading sand and cement is filled.

As described above, even if the adhesive infiltration step (S21) is performed first and then the parent pile driving step (S22) is performed, it is possible to prevent the collapse of sand mountains and the like in the excavation step (S23). Further, since the adhesive-penetrated soil 5 is formed first, the scaffolding during work can be stabilized, and the driving machine or the like of the main pile 1 can be easily transported.

FIG. 8 is a flowchart of the Yamadome construction method according to the second modification. In the modification, the adhesive permeation step is divided into two steps, a first adhesive permeation step (S31) and a second adhesive permeation step (S33), before and after the parent pile driving step (S32). That is, after the water-soluble adhesive 4 is sprayed in the first adhesive infiltration step (S31) to form the adhesive infiltrated soil 5, the parent pile 1 is driven in the parent pile driving step (S32). Subsequently, as the second adhesive infiltration step (S33), the water-soluble adhesive 4 is sprayed on the peripheral region where the main pile 1 is driven, that is, the region to be the mountain retaining surface, and the excavation step (S34) and the horizontal sheet pile insertion are sequentially performed. The step (S35) and the backfilling material filling step (S36) are performed.

Since the adhesive permeation step is divided into two steps, a first adhesive permeation step (S31) and a second adhesive permeation step (S33), before and after the parent pile driving step (S32), it is necessary in each step. It is possible to carry out detailed construction according to the soil adhesion of the area and the ground 9.

In the above embodiment, the excavation method is described as an excavation method in a sandy area where the groundwater level does not need to be considered. However, when the groundwater level is high, the groundwater level is first lowered by a deep well, and then the adhesive infiltration step is performed. By spraying and infiltrating the water-soluble adhesive 4, the subsequent Yamadome construction portion (excavation step, horizontal sheet pile insertion step, backfill material filling step, etc.) can be carried out. It can also be applied to other soils in sandy areas depending on the soil quality. For example, it is effective in gravel ground. There is a lot of gravel ground near the river. In the case of near a river, the groundwater level is high, so first lower the groundwater level with a deep well, and then spray and permeate the water-soluble adhesive 4 as an adhesive permeation step to strongly bond the gravel to each other. In this case, as the water-soluble adhesive 4, for example, there is one in which a special rubber asphalt emulsion is mixed with a curing agent as a main agent. Subsequent Yamadome construction parts (excavation process, horizontal sheet pile insertion process, backfill material filling process, etc.) are the same as those in the above-described embodiment.

1 Parent pile (H-shaped steel)
11 Main pile flange 12 Main pile web 2 Horizontal sheet pile 4 Water-soluble adhesive 5 Adhesive infiltrated soil 9 Ground 91 Slope 92 Excavation surface 96 Shrinkage crack 98 Particles

Claims (1)

In the Yamadome construction method using the parent pile horizontal sheet pile,
The parent pile driving process, in which multiple parent piles are driven into the ground at intervals,
An adhesive infiltration step of infiltrating the water-soluble adhesive into the ground between the parent piles and solidifying the ground,
After the solidification of the ground infiltrated with the water-soluble adhesive, the ground is excavated and the horizontal sheet pile is inserted between the parent piles, and the horizontal sheet pile insertion step.
Including
A mountain retaining construction method characterized in that the water-soluble adhesive is infiltrated from the ground surface around the parent pile in the depth direction to at least a depth at which a space for inserting the horizontal sheet pile is secured .

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