JP2009293331A - Structure of retaining wall formed of soil improvement object and its construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a retaining wall formed of a soil improvement object capable of facilitating a construction operation by eliminating the problems of the concrete retaining wall. <P>SOLUTION: This retaining wall formed of a soil improvement object comprises: a bottom ground improvement object 1 formed by soil-improving the dug section of a foundation ground B; a retaining wall section soil improvement object 2 which is formed by soil-improving the bank on the bottom ground improvement object 1 and which has a plurality of vertical soil improvement objects 2A, 2B, ..., 2E stacked in order in such a manner that a slope S is continuously formed; a water permeable layer 3 which is formed by digging the bank on the rear sides of the ground improvement objects 2A, 2B, ..., 2E and placing a back filler 4 therein and which is brought into contact with the rear surface of the retaining wall section soil improvement object 2 and extends in the vertical direction; a drain pipe 5 which extends from the water permeable layer 3 to the slope S of the retaining wall section ground improvement object 2 and which drains the water on the rear side of the retaining wall section soil improvement object 2 to the front side; and a protective member for protecting the slope S and the upper surface C of the retaining wall section soil improvement object 2 and the upper surface D of the water permeable layer 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a structure of a retaining wall for earth retaining and a construction method thereof, and more particularly to a structure of a retaining wall made of a ground improvement body replacing a concrete retaining wall and a construction method thereof.

  Concrete retaining walls are widely used as retaining retaining walls to prevent the slope from collapsing, and as gravity concrete retaining walls, reinforcing bars are placed in the formwork assembled at the construction site, and concrete is placed. Precast concrete blocks are stacked on the construction site (hereinafter referred to as “on-site concrete method”) and on the top, bottom, left and right of the construction site, and reinforcing bars are disposed in the gaps communicating with the top and bottom of these blocks. Concrete construction (hereinafter referred to as “precast concrete block stacking method”; see, for example, Patent Document 1), L-shaped concrete retaining wall made of reinforced concrete, which is a precast molded product consisting of a wall and a bottom plate Wall blocks that are installed side by side on the construction site (“L-shaped concrete block” Click parallel 設方 formula "hereinafter. For example, refer to Patent Document 2.), And the like.

Japanese Patent Laying-Open No. 2005-98093 (FIG. 1) Registered Utility Model No. 3022072 (FIGS. 1 and 6)

The cast-in-place concrete method requires assembly work for the formwork, work for placing the reinforcing bars in the formwork, and work for dismantling the formwork after the ready-mixed concrete is solidified. Skilled workers such as formwork are required.
In addition, in the precast concrete block stacking method, if the block shape is large, heavy equipment is required to lift the block during construction. If the block shape is small, it takes time to stack the blocks one by one. In both cases where the shape is large and small, it is necessary to perform on-site work in which reinforcing bars are disposed in the gaps communicating with the upper and lower blocks stacked vertically and horizontally and filled with concrete.
Furthermore, in the L-type concrete block side-by-side system, the shape and weight of the retaining wall block is large, so a large heavy machine that lifts the block during transportation and construction is required, and adjacent retaining wall blocks are connected and fixed. Connecting hardware is required.
As described above, the concrete retaining wall has problems that it takes time to construct and the construction cost increases.

  Therefore, in view of the above-mentioned situation, the present invention intends to solve the problem of the above-mentioned concrete retaining wall, and the structure of the retaining wall made of the ground improvement body that can facilitate the construction work and The point is to provide the construction method.

  In order to solve the above problems, the retaining wall structure comprising the ground improvement body according to the present invention comprises a bottom ground improvement body formed by ground improvement of a dug portion of the foundation ground, and a fill on the bottom ground improvement body. A retaining wall part ground improvement body composed of a plurality of upper and lower ground improvement bodies, which are formed by improving the ground and sequentially stacked so that the slope is continuous, and the backside embankment of the plurality of upper and lower ground improvement bodies are dug down. A water permeable layer formed by filling a filling material and extending in a vertical direction in contact with a back surface of the retaining wall portion ground improvement body, and extending from the water permeable layer to a slope of the retaining wall portion ground improvement body, and the retaining wall The drainage pipe which drains the water of the back side of a partial ground improvement body to the front side, and the protection member which protects the slope and upper surface of the said retaining wall part ground improvement body, and the upper surface of the said water permeable layer.

  Here, it is preferable that an uneven engagement portion is formed on the joint surface between the upper and lower ground improvement bodies of the bottom ground improvement body and the retaining wall ground improvement body, or a dowel extending over the joint surface is disposed.

  Moreover, it is preferable when the joint surface between the upper and lower ground improvement bodies of the bottom ground improvement body and the retaining wall ground improvement body is a front rising slope.

  Further, the retaining wall portion ground improvement body is a plane composed of a front wall-like ground improvement body forming a slope and a plurality of vertical wall-like ground improvement bodies extending rearward from the back surface of the front wall-like ground improvement body. It is preferable to have a substantially comb tooth shape.

  In order to solve the above problems, the method of constructing a retaining wall comprising a ground improvement body according to the present invention digs up the surface layer portion of the foundation ground, adds and mixes the solidified material into the soil taken by the digging, backfills and lays the floor. And forming a bottom ground improvement body by compacting, a step of performing stepped banking extending forward from a slope of the rear side ground to a desired retaining wall slope, and the stepped banking on the lower ground A step of digging up to the upper surface of the improved body, a step of adding and mixing the solidified material to the soil taken by the digging, backfilling and leveling, compacting, and forming an upper ground improvement body by shaping the legal gradient, Before or during the formation of the upper ground improvement body, a step of laying a drain pipe extending from the slope to the back surface, and a step of digging the backside embankment of the upper ground improvement body and filling a backfill material. repeat Retaining wall part ground improvement body consisting of a plurality of upper and lower ground improvement bodies stacked sequentially so that slopes are continuous, a water permeable layer extending in the vertical direction in contact with the back surface of the retaining wall part ground improvement body, and the retaining wall part ground A step of constructing a drain pipe for draining water on the rear side of the improved body to the front side on the bottom ground improved body, and a protective work for the slope and upper surface of the retaining wall ground improved body and the upper surface of the water permeable layer The process of performing.

The structure of the retaining wall comprising the ground improvement body according to the present invention is formed by improving the ground on the bottom ground improvement body formed by improving the ground of the dug-down portion of the foundation ground, and the embankment on the bottom ground improvement body, Retaining wall part ground improvement body consisting of a plurality of upper and lower ground improvement bodies stacked sequentially so that the slopes are continuous, and filled with backfill material by digging the backside embankment of the plurality of upper and lower ground improvement bodies A permeable layer extending vertically in contact with the back surface of the retaining wall portion ground improvement body, and extending from the permeable layer to the slope of the retaining wall portion ground improvement body, and on the back side of the retaining wall portion ground improvement body A drainage pipe for draining the water of the water to the front side, and a protective member for protecting the slope and upper surface of the retaining wall portion ground improvement body and the upper surface of the water permeable layer, so that the bottom ground improvement body formed by ground improvement Supports the retaining wall part ground improvement body formed by ground improvement by In addition, since it is configured to receive earth pressure by the retaining wall portion ground improvement body, it is not necessary to perform assembly work and dismantling work of the formwork as in the on-site concrete method, so that the work can be simplified. Skilled workers such as formwork are not required.
In addition, a heavy machine for lifting the blocks as in the precast concrete block stacking method is not necessary, and it is not necessary to arrange the bars in the gaps communicating with the top and bottom of the blocks stacked vertically and horizontally and to fill the concrete.
In addition, a large heavy machine for lifting the blocks as in the L-shaped concrete block side-by-side system is not required, and a connecting bracket for connecting and fixing adjacent retaining wall blocks is not required.
Therefore, the construction period for constructing the retaining wall can be shortened and the construction cost can be reduced.

  In addition, when the concave and convex engaging portions are formed on the joint surface between the upper and lower ground improvement bodies of the bottom ground improvement body and the retaining wall ground improvement body, or dowels extending above and below the joint surface are disposed, the above effect is achieved. In addition, since the displacement between the upper and lower ground improvement bodies can be more effectively suppressed, the shape of the retaining wall can be stably maintained over a long period of time even if there is a change in earth pressure or the like.

Furthermore, when the joint surface between the upper and lower ground improvement bodies of the bottom ground improvement body and the retaining wall ground improvement body is a front rising slope surface, in addition to the above effect, the upper ground improvement body is a front rising slope surface due to its gravity. Since the component force in the direction of moving to the back side along the surface acts, and therefore can resist a greater earth pressure, the length of the ground improvement body in the front-rear direction can be reduced, so the ground improvement is performed. The range can be reduced.
Therefore, since the excavation range of the embankment and the amount of ground improvement body can be reduced, the construction period can be further shortened and the construction cost can be reduced.

Furthermore, the retaining wall portion ground improvement body is composed of a front wall-like ground improvement body forming a slope and a plurality of vertical wall-like ground improvement bodies extending rearward from the back surface of the front wall-like ground improvement body. When viewed as a substantially comb tooth in plan view, in addition to the above effects, the vertical wall-shaped ground improvement body extending rearward from the back surface of the front wall-shaped ground improvement body prevents the retaining wall from falling forward, and the retaining wall portion ground Since the strength and rigidity of the improved body are also increased, the volume of the entire ground improvement body can be reduced as a tooth-like ground improvement body having a substantially comb shape in a plan view, and therefore the range of ground improvement can be reduced.
Therefore, since the excavation range of the embankment and the amount of ground improvement body can be reduced, the construction period can be further shortened and the construction cost can be reduced.

  The method of constructing the retaining wall comprising the ground improvement body according to the present invention is to dig down the surface layer portion of the foundation ground, add and solidify the solidified material to the soil taken by the digging down, lay and spread, and compact, A step of forming a bottom ground improvement body, a step of performing stepped banking extending forward from the slope of the rear side ground to a desired retaining wall slope, and a step of digging the staged banking to the upper surface of the lower ground improvement body , A step of forming a higher ground improvement body by adding a solidifying material to the soil taken by the dug, mixing, backfilling, leveling, compacting, and shaping the normal gradient, before the formation of the upper ground improvement body Or, in the middle of formation, repeating the process of laying a drain pipe extending from the slope to the back and the process of digging the back side embankment of the upper ground improvement body and filling the backfill material, the slope is continuous. Like Next, a retaining wall portion ground improvement body comprising a plurality of upper and lower ground improvement bodies stacked, a water permeable layer extending in a vertical direction in contact with the rear surface of the retaining wall portion ground improvement body, and water on the back side of the retaining wall portion ground improvement body A drainage pipe for draining the water to the front side, and a process for constructing the slope and upper surface of the retaining wall part ground improvement body and a protection work for the upper surface of the water permeable layer. The process of assembling the mold like the cast-in-place concrete method, the process of disposing the reinforcing bars in the mold, and the process of dismantling the mold after the ready-mixed concrete is eliminated.

In addition, the process of lifting the block by a heavy machine such as the precast concrete block stacking system, the process of arranging the bars in the gaps communicating with the upper and lower blocks, and the process of filling the concrete are unnecessary.
Furthermore, the process of lifting the block with a large heavy machine such as an L-shaped concrete block side-by-side system and the fixing for connecting and fixing adjacent retaining wall blocks with connecting metal fittings become unnecessary.
Therefore, since the construction method of the retaining wall can be simplified, the construction period for constructing the retaining wall can be shortened, and the construction cost can be reduced.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments shown in the accompanying drawings, and includes all the embodiments that satisfy the requirements described in the claims. . In addition, in this specification, it shall refer to front and rear, right and left toward the front side from the back side of a retaining wall (refer arrow F in a figure).

Embodiment 1 FIG.
1 is a longitudinal side view showing a structure of a retaining wall made of a ground improvement body according to Embodiment 1 of the present invention, FIG. 2 is a front view of the same, and FIG. 3 is a longitudinal section showing a method for constructing a retaining wall made of a ground improvement body. FIG. 3A is a side view, FIG. 3A shows a state where a stepped embankment 8A is performed on the bottom ground improvement body 1, and FIG. 3B shows a drainage pipe 5A laid to form a ground improvement body 2A. The state where the step-like embankment 8B was performed after filling the backfill material 4 is shown.

As shown in FIG. 1, the retaining wall made of the ground improvement body according to the first embodiment of the present invention is formed by cutting and banking the original ground A, and the ground improvement of the dug portion of the foundation ground B is performed. A plurality of upper and lower ground improvement bodies 2A, 2B, ... formed by improving the embankment on the bottom ground improvement body 1, the ground improvement on the bottom ground improvement body 1, and sequentially stacked so that the slope S is continuous. , 2E retaining wall part ground improvement body 2, and a plurality of upper and lower ground improvement bodies 2A, 2B,..., 2E are dug down and filled with a backfill material 4 made of crushed stone or gravel, for example. The permeable layer 3 extending in the vertical direction in contact with the rear surface of the retaining wall portion ground improvement body 2, extending from the permeable layer 3 to the slope S of the retaining wall portion ground improvement body 2, and the rear surface of the retaining wall portion ground improvement body 2 Drainage pipe 5 for draining the water on the front side, slope S and upper surface C of retaining wall part ground improvement body 2, and Protecting the upper surface D of the aqueous layer 3, a protective member 6 is, for example, mortar or spraying of soil dressing or vegetation mat or sticking, etc. of the straw mat.
Moreover, the bottom ground improvement body 1 has laminated | stacked the substantially horizontal plate-shaped upper bottom part ground improvement body 1B which made the front surface the slope S on the substantially horizontal plate-like lower bottom part ground improvement body 1A. Although the upper part of the upper bottom ground improvement body 1B is exposed from the substantially horizontal ground, the bottom ground improvement body 1 is not limited to such a configuration composed of the upper and lower ground improvement bodies 1B and 1A. The shape of the bottom ground improvement body 1 is not limited to the structure shown in FIG.

  As shown in FIG. 1 and FIG. 2, the drain pipe 5 is spaced apart in the up-down direction and the left-right direction, that is, in the left-right direction below the ground improvement body 2A on the bottom ground improvement body 1. The drainage pipes 5A,..., Spaced apart from each other, and the drainage pipes 5B,..., The ground on the ground improvement body 2B, spaced apart in the left-right direction below the ground improvement body 2B on the ground improvement body 2A. Drain pipes 5C arranged in the lower part of the improved body 2C, spaced apart in the left-right direction,... Drain pipes 5D arranged in the lower part of the ground improved body 2D on the ground improved body 2C, separated in the left-right direction. ,..., And drain pipes 5E,... Disposed below the ground improvement body 2E on the ground improvement body 2D and spaced apart in the left-right direction.

  Moreover, the joint surface between the upper and lower ground improvement bodies 2E and 2D of the retaining wall portion ground improvement body 2, the joint surface between the upper and lower ground improvement bodies 2D and 2C, the joint surface between the upper and lower ground improvement bodies 2C and 2B, On the joint surface between the ground improvement bodies 2B and 2A, the concave portions 7A formed on the left and right sides of the lower ground improvement body, respectively, and the convex portions 7B formed on the left and right sides of the upper ground improvement body, respectively. Since the concavo-convex engaging portions 7, ... are formed, the displacement between the upper and lower ground improvement bodies can be more effectively suppressed, so even if there is a fluctuation in earth pressure, etc. The shape of the retaining wall can be stably maintained over a long period of time.

Here, instead of the concave and convex engaging portions 7,..., Dowels that extend above and below the joint surface between the upper and lower ground improvement bodies may be disposed, and the configuration in which such dowels are disposed is better. Its construction is simplified.
Further, an uneven engagement portion may be formed on the joint surface between the bottom ground improvement body 1 and the ground improvement body 2A on the upper side, or the joint surface between the bottom ground improvement body 1 and the ground improvement body 2A. A dowel that extends vertically may be provided.
In addition, since a frictional force acts on the joint surface between the upper and lower ground improvement bodies and the displacement is suppressed, the uneven engagement portion 7,... Or the dowel is not an essential configuration, but depends on the place where the retaining wall is constructed. Can eliminate the concave and convex engaging portions 7,... Or the dowels, and according to such a configuration, the construction is further simplified.

Next, with reference to FIGS. 1-3, the detail of the construction method of the retaining wall which consists of a ground improvement body is demonstrated.
The surface layer part of the foundation ground B is dug into a predetermined shape by dredging with a backhoe, etc., and the cement-based solidified material composed of components such as silicon dioxide, aluminum oxide, calcium oxide and sulfur trioxide in the soil taken by the dug By adding, mixing, backfilling and leveling and solidifying with a heavy machine and a roller, for example, a lower ground improvement body 1A having a height of about 1 m is formed.
Next, for example, after changing the date (after a certain time) to harden the lower bottom ground improvement body 1A, the solidified material is added and mixed to the soil taken by the dug down on the lower bottom ground improvement body 1A. For example, an upper bottom ground improvement body 1B having a height of about 1 m is formed by backfilling, leveling and compacting.

Next, for example, after changing the date (after a certain time) to harden the upper bottom ground improvement body 1B, on the upper bottom ground improvement body 1B, as shown in FIG. Extending from the slope SB to the desired retaining wall slope S forward, for example, a stepped bank 8A having a height of about 1 m, and digging the stepped bank 8A to the upper surface of the upper bottom ground improvement body 1B, After laying the drain pipes 5A, ..., adding the solidification material to the soil taken by the dug down, backfilling, leveling, compacting, and improving the ground by shaping the legal gradient by, for example, sanding Form body 2A.
Then, the backfill material 4 is filled by digging up the back embankment 8A of the ground improvement body 2A.
Note that the drain pipes 5A,... May be laid at an intermediate position in the height direction of the ground improvement body 2A during the formation thereof, not before the formation of the ground improvement body 2A.

Next, for example, after the ground improvement body 2A is hardened by changing the date (after a certain period of time), the slope SB of the rear side ground is formed on the ground improvement body 2A as shown in FIG. A step-like embankment 8B having a height of about 1 m, for example, extending forward from a desired retaining wall slope S to the front is performed, and the same operation as that described above is performed.
That is, after digging the stepped embankment 8B to the upper surface of the ground improvement body 2A, laying the drainage pipes 5B,... Then, the ground improvement body 2B is formed by shaping the normal gradient, and the backfill material 4 is filled by digging up the embankment 8B on the back side.

  The step of performing stepped banking 8A, 8B,... Extending forward from the slope SB of the rear side ground to the desired retaining wall surface S, and the stepped banking 8A, 8B,. The process of digging up to the upper surface of 1, 2A, ..., adding and mixing the solidified material to the soil taken by digging, backfilling, leveling, compacting, and shaping the legal gradient, the upper ground improvement body 2A, 2B, ..., the process of laying drain pipes 5A, ..., 5B, ... extending from the slope S to the back before or during the formation of the upper ground improvement bodies 2A, 2B, ..., and the upper ground improvement The process of digging down the embankment 8A, 8B,... On the back side of the bodies 2A, 2B,. Multiple ground improvement bodies 2A and 2B Drain which drains the water on the back side of the retaining wall part ground improvement body 2, the water permeable layer 3 extending in the vertical direction in contact with the back surface of the retaining wall part ground improvement body 2 and the back side of the retaining wall part ground improvement body 2 to the front side The pipe 5 is constructed on the bottom ground improvement body 1.

  Next, as shown in FIG. 1, the slope S and the upper surface C of the retaining wall portion ground improvement body 2 and the upper surface D of the water permeable layer 3 are protected. That is, for example, mortar or soil is sprayed or a vegetation mat or cocoon is applied to the slope S and the upper surface C of the retaining wall portion ground improvement body 2 and the upper surface D of the water permeable layer 3.

According to the construction method of the retaining wall made of the ground improvement body as described above, the process of assembling the formwork like the cast-in-place concrete method, the process of arranging the reinforcing bars in the formwork, and the formwork after the ready-mixed concrete is solidified The process of dismantling becomes unnecessary.
Moreover, the process of lifting the block by a heavy machine such as the precast concrete block stacking system, the process of arranging the bars in the gaps communicating with the top and bottom of the blocks stacked vertically, and the process of filling the concrete are not required.
Further, the process of lifting the block by a large heavy machine such as an L-shaped concrete block side-by-side system and the fixing for connecting and fixing the adjacent retaining wall blocks by the connecting metal fitting are not required.
Therefore, since the construction method of the retaining wall can be simplified, the construction period for constructing the retaining wall can be shortened, and the construction cost can be reduced.

Embodiment 2. FIG.
4 is a longitudinal side view showing a structure of a retaining wall made of a ground improvement body according to Embodiment 2 of the present invention, and FIG. 5 is a sectional view taken along the line XX of FIG. The same reference numerals as in FIG. 3 indicate the same or corresponding parts. The retaining wall made of the ground improvement body according to the second embodiment is constructed by the same method as in the first embodiment.

In the second embodiment, the plurality of upper and lower ground improvement bodies 2A, 2B,..., 2E have the same shape, and the front wall forming the slope S of the retaining wall portion ground improvement body 2 as shown in FIG. And a plurality of vertical wall-shaped ground improvement bodies 10 that extend rearward from the back surface of the front wall-shaped ground improvement body 9 and that are separated in the left-right direction, and have a substantially comb-like shape in plan view. Therefore, the embankment 8 </ b> C remains in the substantially U-shaped portion in plan view between the vertical wall-like ground improvement bodies 10, 10 adjacent to the left and right.
In addition, the drain pipe 5 extends from the slope S of the retaining wall portion ground improvement body 2 to the water permeable layer 3 in contact with the back surface of the vertical wall ground improvement body 10, where the vertical wall ground improvement body 10,. Arranged to reach.
Here, the depth E of the retaining wall portion ground improvement body 2 and the height of the retaining wall portion ground improvement body 2 are the lengths in the front-rear direction from the front surface of the front wall ground improvement body 9 to the rear surface of the vertical wall ground improvement body 10. The ratio (E / H) to the height H is about 0.3 to 0.4.

According to the structure of the retaining wall composed of the ground improvement body as described above, the vertical wall-like ground improvement body 10 extending backward from the back surface of the front wall-like ground improvement body 9 prevents the retaining wall from falling forward. In addition, since the strength and rigidity of the retaining wall portion ground improvement body 2 also increase, the ground improvement bodies 2A, 2B,... Therefore, the range for ground improvement can be reduced.
Therefore, since the excavation range of the embankment and the amount of ground improvement body can be reduced, the construction period can be further shortened and the construction cost can be reduced as compared with the retaining wall structure of the first embodiment.

Embodiment 3 FIG.
FIG. 6 is a longitudinal side view showing the structure of a retaining wall made of a ground improvement body according to Embodiment 3 of the present invention. The same reference numerals as those in FIG. 1 of Embodiment 1 and FIG. 4 of Embodiment 2 are the same or The corresponding part is shown. The retaining wall made of the ground improvement body according to the third embodiment is constructed by the same method as in the first embodiment.

In Embodiment 3, the plurality of upper and lower ground improvement bodies 2A, 2B,..., 2E are joined surfaces between the upper and lower ground improvement bodies, that is, the joint surfaces between the ground improvement bodies 2A and 2B, the ground improvement bodies 2B, The joint surface between 2C, the joint surface between the ground improvement bodies 2C and 2D, and the joint surface between the ground improvement bodies 2D and 2E are inclined upwards.
Therefore, a component force in the direction in which the upper ground improvement body moves forward along the inclined surface due to the gravity acts on the back side, and can resist a larger earth pressure. Since the length can be reduced, the range for ground improvement can be reduced.
Therefore, since the excavation range of the embankment and the amount of ground improvement body can be reduced, the construction period can be further shortened and the construction cost can be reduced.
In addition, it is good also considering the joining surface between the bottom part ground improvement body 1 and the ground improvement body 2A on it as a front rising inclination surface.

In the above description, when soil is improved by adding and mixing solidified material such as cement-based solidified material composed of components such as silicon dioxide, aluminum oxide, calcium oxide and sulfur trioxide, etc., to the soil taken by digging However, reinforcing fibers such as rock wool fibers, PVA fibers, polypropylene fibers or steel fibers (for example, fibers having a fiber length of about several mm to several tens mm) are sufficiently dispersed and mixed in the solidified material. If such a reinforcing fiber is used, the strength of the bottom ground improvement body 1 and the retaining wall ground improvement body 2 is increased, and therefore the amount of the ground improvement body can be further reduced.
Therefore, the excavation range of the embankment and the amount of ground improvement body can be further reduced to shorten the construction period and the construction cost.

It is a vertical side view which shows the structure of the retaining wall which consists of a ground improvement body which concerns on Embodiment 1 of this invention. It is also a front view. It is a longitudinal side view showing the construction method, (a) is a state where a stepped embankment is performed on the bottom ground improvement body, (b) is a backfill material by laying a drain pipe and forming a ground improvement body The state where the step-shaped embankment was performed on the top of which is filled is shown. It is a vertical side view which shows the structure of the retaining wall which consists of a ground improvement body which concerns on Embodiment 2 of this invention. It is arrow XX sectional drawing of FIG. It is a vertical side view which shows the structure of the retaining wall which consists of a ground improvement body which concerns on Embodiment 3 of this invention.

Explanation of symbols

A Original ground B Foundation ground E Depth of retaining wall ground improvement S Slope SB Rear ground slope 1 Bottom ground improvement 2 Retaining wall ground improvement 2A, 2B, 2C, 2D, 2E Ground improvement 3 Water permeable layer 4 Backfill material 5, 5A, 5B, 5C, 5D, 5E Drain pipe 6 Protective member 7 Concave engaging portion 8A, 8B, 8C Stepped embankment 9 Front wall ground improvement body 10 Vertical wall ground improvement body

Claims (5)

A bottom ground improvement body formed by improving the ground excavation of the foundation ground,
Retaining wall part ground improvement body which is formed by ground improvement on the bottom ground improvement body and is composed of a plurality of upper and lower ground improvement bodies which are sequentially stacked so that the slopes are continuous,
A permeable layer extending in the vertical direction in contact with the back surface of the retaining wall portion ground improvement body, formed by digging up the backside embankment of the plurality of upper and lower ground improvement bodies and filled with a backfilling material;
A drainage pipe extending from the water permeable layer to the slope of the retaining wall portion ground improvement body, and draining water on the back side of the retaining wall portion ground improvement body to the front side;
A protective member for protecting the slope and upper surface of the retaining wall portion ground improvement body and the upper surface of the water permeable layer;
Retaining wall structure consisting of ground improvement body characterized by comprising.   2. The ground according to claim 1, wherein an uneven engagement portion is formed on a joint surface between upper and lower ground improvement bodies of the bottom ground improvement body and the retaining wall ground improvement body, or a dowel extending above and below the joint surface is disposed. Retaining wall structure consisting of an improved body.   The structure of the retaining wall which consists of a ground improvement body of Claim 1 which makes a joint surface between the bottom ground improvement body and the ground improvement body of the upper and lower sides of a said bottom part ground improvement body and a ground improvement body a front rising slope.   The retaining wall portion ground improvement body is composed of a front wall-like ground improvement body forming a slope and a plurality of vertical wall-like ground improvement bodies extending rearward from the back surface of the front wall-like ground improvement body. The structure of the retaining wall which consists of a ground improvement body in any one of Claims 1-3 which becomes a tooth shape of a comb. Digging the surface layer part of the foundation ground, adding the solidification material to the soil taken by the digging down, backfilling and leveling, compacting, and forming a bottom ground improvement body,
A step of performing stepped banking extending from the slope of the rear ground to the desired retaining wall slope, a step of digging the stepped bank to the upper surface of the lower ground improvement body, a solidified material on the soil taken by the digging Adding and mixing, backfilling, leveling, compacting, and forming the upper ground improvement body by shaping the normal gradient, before or during the formation of the upper ground improvement body, from the slope to the back Repeating a step of laying a drain pipe extending to the back and a step of digging up the embankment on the back side of the upper ground improvement body and filling a backfilling material, and a plurality of upper and lower layers sequentially stacked so that the slope is continuous Retaining wall part ground improvement body made of ground improvement body, water permeable layer extending in the vertical direction in contact with the back surface of the retaining wall part ground improvement body, and drainage for draining water on the back side of the retaining wall part ground improvement body to the front side Tube, said bottom ground And a step to build on a good body,
A process of protecting the slope and upper surface of the retaining wall portion ground improvement body and the upper surface of the water permeable layer;
A method for constructing a retaining wall comprising a ground improvement body characterized by comprising:

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