JP2985736B2 - Soil retaining wall with water permeability and construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retaining wall having water permeability and a method for constructing the retaining wall.

[0002]

2. Description of the Related Art As is well known, when an underground structure, for example, an underground tunnel for a subway or a vehicle-only road is constructed by an open-cutting method, it is possible to prevent collapse of the ground and excavate the inside. In order to achieve this, a retaining wall with waterproofness is constructed.
Various methods are available for constructing this type of retaining wall, such as the continuous underground wall method, but the retaining wall constructed by the continuous underground wall method and In some cases, it may remain in the ground even after the main body of the underground structure is constructed.

[0003] If a retaining wall having water blocking properties is left in the ground, the groundwater flow will be interrupted, and the water vein downstream of the retaining wall will be interrupted. Inconvenience such as sinking occurs. Therefore, for example, Japanese Patent Application Laid-Open No. 6-49839 discloses a method of constructing a retaining wall capable of securing water-blocking properties when constructing a main body of an underground structure and ensuring water permeability when the main body is completed. Is disclosed.

In the construction method disclosed in this publication, a retaining wall is constructed by a continuous underground wall construction method. When constructing the retaining wall, a hollow circular or square perforated pipe is formed in an excavation hole. Alternatively, a special water-permeable frame with a steel mesh placed in the opening on the ground side is installed vertically, and an impervious and elastic tubular body is inserted into this water-permeable frame, In a state where the water pressure in the body is higher than the surrounding water pressure, concrete is poured, and after the concrete has hardened, the tubular body is removed from the special water flow frame, and the perforated pipe or the ground side opening is removed. The placed steel mesh provides water permeability to the retaining wall.

[0005] The special water-permeable frame is sized to penetrate the retaining wall in the thickness direction or to replace a part of the retaining wall in the thickness direction, and is filled with crushed stone. However, such a conventional retaining wall structure and its construction method have the following technical problems.

[0006]

That is, in the structure of the retaining wall disclosed in the above publication, in order to impart water permeability to the retaining wall, all or a part of the retaining wall in the thickness direction is formed of a special frame. Because of the substitution, this portion could be a structural weak point. In addition, in the method of constructing a retaining wall described in the above publication, a perforated pipe or the like is built in an excavation site filled with muddy water. At the same time, when casting concrete, a tubular body is inserted into the inside to prevent the concrete from wrapping around, but this tubular body is placed inside the water flow frame such as a perforated pipe. Since it is inserted, cement or the like may enter the through-hole of the perforated pipe, causing clogging, and there is a problem that the water permeability of the retaining wall is significantly reduced.

Further, the construction method disclosed in the above-mentioned publication is a method of imparting water permeability to the retaining wall when constructing the retaining wall, and therefore cannot provide water permeability to the already constructed retaining wall. There was also a problem. The present invention has been made in view of such conventional problems,
A first object is to provide a retaining wall having water permeability that allows passage of a groundwater flow without substantially affecting the performance of the retaining wall. Further, as a second object, there is provided a construction method of a retaining wall which does not cause clogging due to the influence of the construction of the retaining wall and which can impart water permeability to an existing structure. It is in.

[0008]

To achieve the above object of the Invention The present invention provides a pair of wall portions facing each other are at a predetermined distance, it is constructed so as to cut off the underground groundwater flow, the wall
In the retaining wall which is left in the ground after excavating the part and constructing the main body part, at predetermined intervals along the longitudinal direction of the wall part, and vertically along the outer surface thereof It extends in the direction,
A plurality of vertical drain passages formed after the construction of the wall portion, a water passage provided between the wall portions, and
A pair of the vertical drain passage and the water passage facing each other
And a horizontal drain passage that communicates through the wall portion, and the vertical drain passage is excavated from the ground.
A drain hole, which is located outward from the outer surface of the wall.
It is characterized by being provided at regular intervals . Further, in a construction method of a retaining wall constructed such that a pair of opposing walls are separated from each other at a predetermined interval to block groundwater flow in the ground, excavation is performed between the walls after the walls are constructed. After constructing the main body by performing root cutting, or at the time of constructing the main body, at a position opposed to the wall, a pair of horizontal extending through the wall and extending outward. Drain passages are formed at a plurality of locations at predetermined intervals along the longitudinal direction of the wall portion, and a water passage communicating between the horizontal drain passages is formed between the wall portions. A vertical drain passage communicating with the horizontal drain passage is formed outside the wall. The horizontal drain passage is constructed by digging and forming a horizontal drain hole in the horizontal direction, and filling the horizontal drain hole with crushed crushed stone, and the leading end side of the horizontal drain passage is located outside the vertical drain passage. The vertical drain passage may be formed by protruding the vertical drain hole from the ground, and filling the vertical drain hole with crushed stone. The waterway,
It is constituted by a water pipe with both ends opened, and the water pipe can be installed at a predetermined position in the bottom plate of the main body in advance, and the water pipe can be embedded in the bottom plate.

[0009]

According to the retaining wall having the above structure, a plurality of vertical walls extending at predetermined intervals along the longitudinal direction of the pair of walls of the facing retaining wall and extending vertically along the outer surface thereof. It has a drain passage, a water passage provided between the walls, and a horizontal drain passage that penetrates the wall and communicates between the vertical drain passage and the water passage. The drained groundwater flows into the water passage through the upstream vertical drain passage and the horizontal drain passage, and flows down from the water passage through the downstream horizontal drain passage and the vertical drain passage. At this time, since only the horizontal drain passage penetrating the wall is provided in the wall, the strength of the wall is hardly affected. Also, especially along the wall
Several vertical drain passages extending downwards are excavated from the ground.
It has a drain hole to be cut away from the outside of the wall.
Drill holes are drilled because they are provided at regular intervals.
The wall without damaging the walls.
Can be Further, according to the construction method of the retaining wall having the above configuration, after constructing the wall portion of the retaining wall, after excavating between the wall portions and performing root cutting to construct the main body portion, or constructing the main body portion. At this time, a pair of horizontal drain passages penetrating the wall portion and extending outwardly, at positions opposed to the wall portion,
Along the longitudinal direction of the wall, formed at a plurality of locations at predetermined intervals, and a water passage communicating between the horizontal drain passages is formed between the walls, and thereafter, communicates with the horizontal drain passage. Since the vertical drain passage is formed outside the wall, the drain passage and the water passage do not become clogged due to the construction work for constructing the wall of the retaining wall. In addition, since the vertical and horizontal drain passages and the water passage communicating with each other are formed after the construction of the main body, it is possible to construct the existing retaining wall. According to the configuration of claim 3, the horizontal drain passage is formed by digging and forming a horizontal drain hole in the horizontal direction, and filling the horizontal drain hole with crushed crushed stone. Since it is formed so as to protrude outside the vertical drain passage, when the drain hole of the vertical drain passage is excavated from the ground, even if the drain hole is shifted from the vertical direction, the vertical drain passage and the horizontal drain It can communicate with the passage.

[0010]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a retaining wall provided with water permeability according to the present invention. The retaining wall 10 shown in the figure has a pair of opposed wall portions 10a, 10a.
b is configured to block the underground groundwater flow 12 at predetermined intervals. Between the walls 10a and 10b,
An underground structure main body 14 is constructed.

The underground structure main body 14 is constructed by an open-cutting method of excavating between the walls 10a and 10b from above after the construction of the retaining wall 10, and the retaining wall 10 remains in the ground even after the construction of the main body 14. Is left behind. The underground structure main body portion 14 shown in this embodiment is an underground tunnel and has a bottom plate 14a, a side plate 14b, and an upper plate 14c.

In the figure, the groundwater flow 12 is divided into two stages at an interval in the vertical direction, and the upper and lower groundwater flows 12a and 12b flow from left to right in the drawing. Outside the pair of walls 10a, 10b, the respective walls 10a, 10b
A plurality of vertical drain passages 16 are provided at predetermined intervals along the longitudinal axis direction of the walls 10a and 10b at an interval from the outer surface of b.

A plurality of vertical drain passages 16 are provided in the wall 10
a, 10b extending vertically along the outer surface of the
a, 10b are opposed to each other with the wall portions 10a,
They are arranged facing each other on an axis orthogonal to 10b. Each vertical drain passage 16 is composed of a circular vertical drain hole 16a excavated from the ground side, and crushed stones 16b filled in the vertical drain hole 16a. The cross-sectional shape of the vertical drain hole 16a is not limited to a circle, and may be, for example, a square or a rectangle. The member filled in the drain hole 16 may be not only the crushed stone 16b but also a cobblestone.

As a means for filling the crushed stone 16b into the vertical drain hole 16a, the crushed stone 16b is directly filled into the drain hole 16a.
In addition to the means for charging crushed stones 16b, for example, a crushed stone 16b is filled in a cylindrical porous tube and inserted into the hole 16a, or a crushed stone 16b is filled in a cylindrical wire mesh. Hole 1
6a can be selected for insertion. The vertical drain passage 16 straddles the groundwater flow 12 located in two stages at an interval in the vertical direction, and the lower side of the lower groundwater flow 1
2b, so that the upper end side is located above the upper groundwater flow 16a.
The upper side of the vertical drain hole 16a is backfilled. A water passage 18 is provided coaxially with a pair of vertical drain passages 16 opposed to each other with the walls 10a and 10b interposed therebetween.

In this embodiment, the water passage 18 is constituted by a water passage pipe 18a having both ends opened, and the pipe 18a is disposed vertically and embedded in the bottom plate 14a and the upper plate 14c, respectively. Have been. The water passages 18 do not need to be provided so as to correspond to all of the pair of vertical drain passages 16 facing each other, and may be provided at appropriate locations, or may be provided at any one of the bottom plate 14a and the upper plate 14c. it can.

The water passage 18 does not have to be provided coaxially with the pair of vertical drain passages 16 facing each other, and may be provided at an eccentric position. For example, when the water passage 18 is applied to an existing earth retaining wall. Need not be embedded in the main body 14. On the other hand, a horizontal drain passage 20 is provided in the walls 10a and 10b so as to penetrate them.

The horizontal drain passages 20 connect the pair of vertical drain passages 16 facing each other to the water passage 18, and are provided at each end of each water passage 18. The horizontal drain passage 20 includes the walls 10a and 10a.
b, and a crushed stone pack 20b filled in the horizontal drain hole 20.
It is composed of

The crushed stone pack 20 is one in which crushed stone is surrounded by a water-permeable bag, and when such a bag 20 is used, when the crushed stone is filled into the horizontal drain hole 20 formed in the horizontal direction, the crushed stone is individually packed. Can be performed more efficiently than when filling with crushed stones and cobblestones. In this embodiment, the horizontal drain passage 20 is set to have a length such that it penetrates the vertical drain passage 16 in the diametrical direction, and its tip is located outside the vertical drain passage 16. In this embodiment, the state in which the horizontal drain passage 20 corresponds to the position of the groundwater flow 12 is illustrated, but the position of the horizontal drain passage 20 is not limited to the illustrated state.

Now, the retaining wall 10 constructed as described above.
, A pair of wall portions 10a, 10b formed opposite to each other
A plurality of vertical drain passages 1 extending at predetermined intervals along the longitudinal direction and extending vertically along the outer surface thereof.
6 and a water passage 18 provided between the walls 10a and 10b.
And a horizontal drain passage 20 that penetrates the vertical drain passage 16 and the water passage 18 through the walls 10a and 10b, so that the groundwater flow 12 blocked by the retaining wall 10 is The water flows into one end of the water passage 20 via the upstream vertical drain passage 16 and the horizontal drain passage 20, and flows down from the other end of the water passage 20 through the downstream horizontal drain passage 20 and the vertical drain passage 16.

Thus, the groundwater flow 12 is divided into the wall portions 10a,
Even if cut off at 10b, groundwater flows downstream, so
Problems such as withering wells and ground collapse on the downstream side are eliminated.
At this time, in this embodiment, since only the horizontal drain passage 20 penetrating the walls 10a and 10b is provided in the walls 10a and 10b,
It hardly affects the strength of the walls 10a and 10b.

FIG. 2 to FIG. 5 show an embodiment of a method of constructing a retaining wall having water permeability according to the present invention. The construction method shown in the figure shows the steps of constructing the retaining wall 10 having the structure shown in FIG. 1. In the construction method, first, the retaining wall 10 is constructed underground. In this embodiment, the retaining wall 10 is constructed by an underground continuous wall method, and is formed such that a pair of reinforced concrete walls 10a and 10b face each other at a predetermined interval (see FIG. 2).

Each of the walls 10a and 10b is formed so as to block the groundwater flow 12 flowing in a two-stage manner so that the lower end thereof reaches an impermeable layer in the ground. When the construction of the base 10 is completed, excavation of the inside surrounded by the walls 10a and 10b is performed.
After this, the formation of the horizontal drain passage 20 is performed.

In this case, in this embodiment, since a plurality of horizontal drain passages 20 are formed at intervals in the vertical direction, a portion where the upper horizontal drain passage 20 is formed is exposed by excavation. This work may be performed. In the formation of the horizontal drain passage 20, each wall 10a,
A horizontal drain hole 20a is formed substantially horizontally at a position facing 10b so as to penetrate the walls 10a and 10b and to extend outside the walls 10a and 10b.

The formation length of the horizontal drain hole 20a at this time is such that a vertical drain passage 16 to be described later is penetrated through a portion where the vertical drain passage 16 is to be formed (indicated by an imaginary line in FIG. 3), and the tip thereof is located further outward. It is performed as follows. When the horizontal drain hole 20a having such a length is formed, the inside thereof is filled with the crushed stone pack 20b. When the horizontal drain hole 20a is drilled, each of the walls 10a, 10b is designed to prevent groundwater from flowing into the interior.
It is desirable that the outside of the container be stopped by a chemical solution injection or a freezing method, or that a water stop valve be provided at the inside end.

When the horizontal drain passage 20 is formed by filling the crushed stone pack 20b into the drain hole 20, the main body 10 is constructed as shown in FIG. Note that FIG.
In the above, the formation position of the horizontal drain passage 20 is made to coincide with the position of the groundwater flow 12, but the horizontal drain passage 2
The position of 0 need not necessarily be provided at this position. In the construction of the main body 14, first, the bottom plate 14 is placed on the root cutting surface 22.
In this case, a water passage 18 is formed, which connects the pair of horizontal drain passages 20 provided at opposing positions at this time.

The water passage 18 is constituted by a water pipe 18 a having both ends opened, and the pipe 18 a is provided with walls 10 a, 1 such that both ends open to the horizontal drain passage 20.
0b, and then concrete is cast to construct the bottom slab 14a. The process of forming the horizontal drain passage 20 shown in FIG. 3 and the bottom plate 14 shown in FIG.
The step of forming the water passage 18 in a may be performed in the reverse order, or may be performed simultaneously.

When the construction of the bottom slab 14a is completed, the construction of the side slab 14b and the upper slab 14c of the main body 14 is performed in this order. The construction work of the water passage 18 is performed. When the construction of the main body 14 is completed, as shown in FIG. 5, the construction of the vertical drain passage 16 is performed.

In forming the vertical drain passage 16, first,
A circular vertical drain hole 16a is excavated from the ground. This vertical drain hole 16a is formed in each of the walls 10a, 10a.
At a position slightly separated outward from the outer surface of b, the lower end is excavated to a depth located below the lower horizontal drain passage 20. When the excavation of the vertical drain hole 16a is completed, the inside thereof is filled with the crushed stone 16b or the boulder.

At this time, the filling amount of the crushed stone 16b is set such that the upper end of the filled crushed stone 16b is higher than the upper horizontal drain passage 20, and the crushed stone 16b is filled to such a position. Later, the vertical drain hole 16
The upper side of a is backfilled with earth and sand, thereby completing the construction. Now, according to the construction method of the retaining wall 10 configured as described above, after constructing the wall portions 10a and 10b of the retaining wall 10, excavation is performed between the wall portions 10a and 10b to perform root cutting, and the main body portion is formed. When constructing the wall 14, the walls 10 a, 10
A pair of horizontal drain passages 20 penetrating the wall portions 10a and 10b and extending outward therefrom are provided at opposing positions at predetermined intervals along the longitudinal direction of the wall portions 10a and 10b. At the same location as the horizontal drain passage 2
A water passage 18 communicating between the spaces 0 is formed between the walls 10a and 10b, and then a vertical drain passage 16 communicating with the horizontal drain passage 20 is formed outside the walls 10a and 10b. Due to the construction work for constructing the walls 10a, 10b of 10, the drain passages 16, 20 and the water passage 18 do not become clogged.

The vertical and horizontal drain passages 16 and 20 and the water passage 18 communicating with each other can be formed even after the main body 14 is constructed. It is possible to make the earth retaining wall of the existing underground structure water-permeable. In the case of the present embodiment, the horizontal drain passage 20 is formed by excavating and forming a horizontal drain hole 20a in the horizontal direction, and filling the horizontal drain hole 20a with crushed stone 20b in a pack shape. Since the front end side of the drain passage 20 is formed so as to protrude outward from the vertical drain passage 16, when the drain hole 16a of the vertical drain passage 16 is excavated from the ground, the drain hole 16a is displaced from the vertical direction. Also in this case, the vertical drain passage 16 and the horizontal drain passage 20 can be reliably communicated.

In the above-described embodiment, the case where the earth retaining wall 10 is constructed by the underground continuous wall method is exemplified as the construction method. However, the embodiment of the present invention is not limited to this. It can also be applied to the case where a retaining wall is constructed by a construction method.

[0032]

As described above in detail in the embodiments,
According to the retaining wall having water permeability according to the present invention, water permeability can be imparted without affecting the performance of the retaining wall. Further, according to the construction method of the earth retaining wall having water permeability according to the present invention, by the construction when constructing the earth retaining wall,
Sufficient water permeability can be ensured without clogging, and the existing underground structure can also have water permeability.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing one embodiment of a retaining wall provided with water permeability according to the present invention.

FIG. 2 is an explanatory sectional view of a first step showing one embodiment of a method of constructing a retaining wall having water permeability according to the present invention.

FIG. 3 is an explanatory cross-sectional view of a step performed after the step of FIG. 2;

FIG. 4 is an explanatory sectional view of a step performed after the step of FIG. 3;

FIG. 5 is an explanatory cross-sectional view of a step performed after the step of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Retaining wall 10a, 10b Wall part 12 Groundwater flow 14 Main body part 14a Bottom plate 14b Side plate 14c Top plate 16 Vertical drain passage 16a Vertical drain hole 16b Crushed stone 18 Water passage 18a Water passage pipe 20 Horizontal drain passage 20a Horizontal drain stone 20b pack

Continuation of the front page (56) References JP-A-6-49839 (JP, A) JP-A-5-247929 (JP, A) JP-A-8-158394 (JP, A) JP-A-8-260498 (JP) , A) JP-B-59-36058 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) E02D 17/04 E02D 3/10 104

Claims (4)

(57) [Claims] 1. A pair of walls facing the at predetermined intervals, are constructed so as to block the underground groundwater flow, the wall
In the retaining wall which is left in the ground after excavating the part and constructing the main body part, at a predetermined interval along the longitudinal direction of the wall part, and
Extending vertically along its outer surface, after the construction of said wall
A plurality of vertical drain passages, a water passage provided between the wall portions, and a pair of the vertical drain passages facing each other with the wall portion interposed therebetween.
And a horizontal drain passage which communicates with the water passage through the wall portion , wherein the vertical drain passage is a drain excavated from the ground.
A hole, spaced apart from the outer surface of the wall by a predetermined distance.
An earth retaining wall with water permeability, characterized by being provided with 2. A method of constructing a retaining wall in which a pair of opposing walls are spaced from each other at a predetermined interval to block groundwater flow in the ground, wherein the wall is constructed after the wall is constructed. After constructing the main body by excavating the roots and performing root cutting, or at the time of constructing the main body, at the position opposed to the wall, it is extended outward through the wall. A pair of horizontal drain passages,
Along the longitudinal direction of the wall, formed at a plurality of locations at predetermined intervals, and a water passage communicating between the horizontal drain passages is formed between the walls, and thereafter, the horizontal drain is formed. A vertical drain passage communicating with the passage is formed outside the wall, and a method of constructing a retaining wall having water permeability. 3. The horizontal drain passage is constructed by digging and forming a horizontal drain hole in a horizontal direction, and filling packed crushed stone into the horizontal drain hole. The vertical drain passage is formed so as to protrude outside the passage, and the vertical drain passage is formed by excavating and forming a vertical drain hole from the ground, and filling the vertical drain hole with crushed stone. Construction method of earth retaining wall with water permeability described. 4. The water passage is constituted by a water passage pipe having both ends opened, and the water passage pipe is previously set at a predetermined position in a bottom plate of the main body, and the water passage pipe is connected to the bottom plate. The method for constructing a retaining wall having water permeability according to claim 2, wherein the retaining wall is buried in the inside.