JP2000160559A - Landslide protection wall and construction method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a landslide protection wall and a construction method therefor improved in a cost and a construction period while solving a problem of vibration/noise by forming a slope face-like land slide protection wall by a ground improvement, restraining a construction site to a arrow range, simplifying a work process, and improving workability. SOLUTION: This landslide protection wall 2 is constituted by superposing landslide protection walls 2 by a ground improvement construction method in a multilayer shape on the excavating side, and heat part arrangement of the respective landslide protection walls 2 and the length of the landslide protection walls 2 are set in response to the earth pressure stress distribution of the ground. Then, in the construction method, the landslide protection wall is constructed by superposing landslide protection walls 2 by a ground improvement construction method in a multilayer shape on the excavating side, but after setting head part arrangement of the landslide protection walls 2 by dryly excavating the ground up to the prescribed depth in response to the earth pressure stress distribution of the ground, a ground improvement is started, and then, the landslide protection wall 2 is formed in the prescribed length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retaining wall and a method of constructing the retaining wall, and more particularly to a method for constructing a retaining wall in a multilayer structure on an excavation side, in which a ground improvement range is set in accordance with the earth pressure stress distribution of the ground. The present invention relates to a retaining wall and a construction method thereof.

[0002]

2. Description of the Related Art In the construction of a structure such as a building, an underground portion is excavated because a basement, a foundation, and the like must be constructed underground. When performing the underground excavation by the open-cut method without a mountain retaining, excavation shall be performed with a gentle slope of 1: 1.5 to 1: 2.0 in order to prevent collapse of earth and sand. There must be. Furthermore, in the ground where the groundwater level is higher than the excavation bottom, groundwater flows out from the excavation slope, so that the surrounding groundwater level decreases, causing problems such as land subsidence. In addition, in the case of building a building in an urban area, etc., there are many restrictions on the site, and in many cases, it is not possible to secure land for providing a slope with a gentle slope as described above. The cost of excavation is high, which is problematic in terms of cost.

[0003] Therefore, it is common to carry out construction using a mountain retaining method. In the mountain retaining method, as shown in FIG. 4, a retaining wall 21 such as a steel sheet pile is laid on a ground 20 in an excavation area to a depth reaching an impermeable layer 22.
In accordance with the progress of the excavation, excavation is performed while installing a girder 23 or a fire girder in the excavated portion with an intermediate pile 24 interposed as necessary, and the above girder is removed according to the construction of the structure and the construction is advanced. I had to. For this reason, the work process became complicated, and the mountain retaining member hindered the workability. In addition, there are cases where vibrations and noises occur when placing the retaining wall, which is not a desirable method in terms of cost and work period.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made to improve the above-mentioned problems.
The construction site is kept in a narrow area, the work process is simplified, the workability is improved, and the cost /
The present invention provides a retaining wall improved in construction period and a method for constructing the retaining wall.

[0005]

According to the present invention, a retaining wall according to the present invention is constructed by layering each retaining wall by a ground improvement method on the excavation side in multiple layers, and determining the head depth of each retaining wall and the length of the retaining wall. It is set according to the earth pressure stress distribution, and is characterized in that at least one of the retaining walls is embedded in the impermeable layer.

[0006] The method of constructing a retaining wall according to the present invention is as follows.
In order to construct each retaining wall by the ground improvement method in multiple layers on the excavation side, set the depth of the head of each retaining wall to the predetermined depth corresponding to the earth pressure stress distribution of the ground, and then set It is characterized in that the ground improvement is started and the retaining wall is formed to a predetermined length.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A retaining wall according to the present invention is constructed by superimposing a retaining wall formed by a ground improvement method on a side on which ground is excavated in multiple layers, and determining the head depth of each retaining wall and the length of the retaining wall. An embodiment that is set according to the distribution will be described with reference to the drawings. FIG. 1 is a sectional view showing an excavated state of the ground constructed by the retaining wall according to the present invention. As shown in the figure, the retaining wall 1 is configured by stacking a plurality of retaining walls 1-1 to 1-6 constructed in the ground 2 in a multilayer structure, and each retaining wall is formed by a normal ground improvement method. It is constructed and constructed as a soil cement water stop wall by the cement stirring and mixing method. The mountain retaining wall 1-1 is disposed on the outermost side of the mountain retaining wall 1 and is formed to be the longest from the ground surface 3 to a depth where it enters the impermeable layer 4, and corresponds to earth pressure stress in the entire ground. In addition, the retaining wall 1-1 functions as a water blocking wall that does not allow groundwater to enter the excavation section 5 by being embedded in the impermeable layer 4, but this role is not limited to any other arrangement described later. In this case, it is sufficient that the water stopping function is maintained in any part.

For each of the retaining walls 1-2 on and after the retaining wall 1-2, the construction position and the construction depth are set in accordance with the stress distribution state caused by the earth pressure of the ground which the retaining wall 1 bears. Therefore, as a matter of course, the arrangement state is such that the pile heads 6 of the retaining walls are arranged stepwise at a position deep from the ground surface 3 toward the ground excavation side, as shown in the figure, and each of the retaining walls 1-2. The length of 1-6 is also shortened temporarily. Mountain retaining wall 1
Is constructed so as to surround the periphery of the excavation part 5 and is structurally strong, so that it is safe at the time of excavating the ground, and even after the building is completed, the retaining wall surrounds the structure and the structure at the time of the earthquake Also has the effect of increasing the resistance to lateral movement.

[0009] Since the soil cement water blocking wall originally has a property of being strong against a compressive force but easily breaking when subjected to a tensile stress, when the soil cement water stopping wall is used alone, If the wall length of the cantilever is long, a tensile stress is generated in the cross section of the soil cement water stop wall due to a load such as earth pressure or seismic force, and there is a risk that even if the wall thickness is increased, the wall is destroyed.
However, when the soil cement water blocking walls are used in an overlapping manner as in the present invention, the length of the cantilever wall of each soil cement water blocking wall becomes short, so that a tensile stress may be generated in its cross section. Fits without any risk of destruction.

As described above, the retaining wall according to the present invention
While retaining the land required for excavation in a narrow range, no stakes such as girder beams or bulging are required, thereby reducing the amount of materials used, making construction easier and improving efficiency. The required construction period is shortened,
It provides mountain retaining walls that have been significantly improved during construction.

Next, a method for constructing a retaining wall according to the present invention will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing a construction state in which a mountain retaining wall is being constructed. Each of the retaining walls 1-1 and the like are constructed and formed as soil cement water stop walls by a cement stirring and mixing method, which is a normal ground improvement method. As shown, the retaining wall 1 that has been completed
-1 is most constructed on the ground 2 side, and is constructed so as to correspond to the total stress of the soil pressure from the ground surface 3 to the penetration into the impermeable layer 4 and to function as a water blocking wall. .

In the case of the retaining wall 1-1, the ground improvement machine 7
Excavation from the ground surface 3 and cement agitation mixing process are performed to form a soil-cement water stop wall. The construction state also differs from the case of the retaining wall 1-1. That is, in the case of the retaining wall 1-2, the formation of the excavation hole 8 by the ground improvement machine 7 is performed by digging without mixing cement from the ground surface 3 to a depth that does not require stress sharing. Next, a regular cement agitation mixing process in which cement is mixed from the depth where stress sharing is required is performed to form a soil cement water blocking wall to a depth next to the retaining wall 1-1, but a water stopping function is required. The construction is completed at a depth where the necessary strength can be exhibited within a range that does not reach the impermeable layer.

Accordingly, the pile head 6 of the retaining wall 1-2 is disposed at a predetermined depth of the backfilled excavation hole 8, but the pile head 6 of each of the retaining walls is also shown in FIG. In this way, they are arranged at a depth with a predetermined slope angle for a while, and the depths (lengths) of the retaining walls are shortened in order to share the necessary stress with the decreasing ground pressure of the ground. .

FIG. 3 is a cross-sectional view showing a state of excavation after the construction of the soil cement water blocking wall is completed. The soil cement waterproof wall 1 constructed in FIG. 2 has the ground 2 as seen in the arrangement of the heads 6 set in accordance with the earth pressure gradient of the ground.
It is configured to form a slope that can be constructed while preventing collapse of the excavated surface during excavation. The digging work of the digging part 5 is performed by digging the digging hole 8 digged by the digging machine 9 in an open cut along the slope regulated by the pile head 6 of the retaining wall 1.

The state shown in the figure shows a stage in which the above-described excavation on the slope is completed and the excavation section 5 for constructing the structure is leveled. Since it is reliably supported by the formed retaining wall 1, excavation work can be performed without requiring any retaining material such as a cut beam or an intermediate pile as in the related art. Also, since the slope 10 formed by the retaining wall 1 can be made steeper than the slope of the normal open cut method, the construction site is kept in a narrow range with respect to the site necessary for constructing the structure. be able to.

As described above, the retaining wall according to the present invention and the method for constructing the same are described in detail based on the embodiments.
The construction site is narrowed by stacking the retaining walls by the ground improvement method on the excavation side in multiple layers and setting the head depth and the retaining wall length of each retaining wall corresponding to the earth pressure stress distribution of the ground. However, the present invention is not intended to be limited to the above-described embodiment, and does not deviate from the gist of the present invention, since the purpose of the present invention is to eliminate the need for any retaining material such as a cut beam or a belly. It goes without saying that various changes are possible in.

[0017]

The retaining wall according to the present invention is constructed by layering the retaining wall formed by the ground improvement method on the excavation side in multiple layers, and adjusting the head depth and the retaining wall length of each retaining wall to the earth pressure stress distribution of the ground. It is characterized in that at least one of the retaining walls is embedded in the water-impermeable layer, and the method of constructing the retaining wall according to the present invention comprises the steps of: In order to construct the pile on the excavation side in multiple layers, the depth of the head of each retaining wall is set by digging to a predetermined depth corresponding to the earth pressure stress distribution of the ground, and then the ground improvement is started and the retaining wall is started. The construction length is reduced to a predetermined length, which makes it possible to narrow the construction site, and also eliminates the need for ridges such as cut beams and erections, thus reducing construction costs. And materials used, construction period and construction efficiency And provide an advantage to be.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a retaining wall according to the present invention.

FIG. 2 is an excavation process chart of a retaining wall pile according to the present invention.

FIG. 3 is an excavation process diagram inside the retaining wall according to the present invention.

FIG. 4 is a sectional view of a conventional retaining wall.

[Explanation of symbols]

 Reference Signs List 1 mountain retaining wall 1-1 to 1-6 individual mountain retaining wall 2 ground 3 ground surface 4 impermeable layer 5 excavation section 6 head of mountain retaining wall 7 ground improvement machine 8 drilling hole 9 excavating machine 10 slope 20 ground 21 soil Retaining wall 22 Impermeable layer 23 Cut beam 24 Intermediate pile

Claims (3)

[Claims] Claims 1. A retaining wall formed by a ground improvement method,
A mountain retaining wall comprising a plurality of the retaining walls stacked on the excavation side, and a head depth and a length of each retaining wall set in accordance with an earth pressure stress distribution of the ground. 2. The retaining wall according to claim 1, wherein at least one of the retaining walls is embedded in the impermeable layer. 3. A method of constructing a retaining wall by a ground improvement method, wherein the retaining wall is stacked on the excavation side in multiple layers, and the head depth of each retaining wall corresponds to the earth pressure stress distribution of the ground. A method for constructing a retaining wall, wherein the retaining wall is set to a predetermined depth, and then the ground improvement is started to form the retaining wall to a predetermined length.