JP4914062B2 - Two-tiered retaining wall and its construction method - Google Patents

Description

The present invention is such that, for example, a building in which a dry area provided for a daylighting space is formed on the outer periphery of a building, and a basement floor is formed to a deeper position on the inside thereof, the lower depth of the underground frame is the outer periphery. It is related with the two-tiered mountain retaining wall and its construction method used for underground construction of different buildings inside and outside.

When the depth of the lower part of the underground frame is different between the outer peripheral part and the inside, as shown in FIG. Reference numeral 1 denotes an outer mountain retaining wall, and 2 denotes an inner mountain retaining wall constructed inside the outer mountain retaining wall 1 with a step excavation portion 3 therebetween. When the groundwater level L is high, a soil cement column wall or the like having high water stopping performance is adopted as the outer mountain retaining wall 1 so that the outer mountain retaining wall 1 becomes a water shielding wall. Pile horizontal sheet pile walls are used.

If the lateral resistance of the outer retaining wall 1 or the resistance of the rooted part is not enough to withstand lateral pressure,
A support is used. As for the support work, if it is more advantageous in terms of construction and cost than adopting a cut beam, and there is room in the site, for example, as shown in the figure, the outer mountain retaining wall 1 and a cut placed outside thereof The pile 6 is connected by a tie rod 7, and the inner mountain retaining wall 2 is supported by a ground anchor 9.

However, the conventional double-tiered retaining wall has the following problems.
(1) Since each of the outer mountain retaining wall 1 and the inner mountain retaining wall 2 is designed and constructed independently, it becomes overspec (excessive quality), which is uneconomical.
(2) The synergistic effect due to the fact that the mountain retaining walls 1 and 2 are parallel to each other cannot be exhibited. For example, when the groundwater level of the original ground is high, as shown in the figure, when the outer mountain retaining wall 1 is used as a water blocking wall and the inner mountain retaining wall 2 is used as a ground anchor type, the anchoring portion of the ground anchor 9 on the inner mountain retaining wall 2 is used. Penetrates the water-impervious wall (outer mountain retaining wall 1), and water stoppage cannot be ensured. Further, since the fixing portion of the ground anchor 9 interferes with the core material 1a of the outer mountain retaining wall 1, the design of the core material length is limited. And since the construction of the ground anchor 9 is performed in the middle of excavation of the internal ground of the inner side retaining wall 2, a construction period becomes long and cost increases.

Patent Document 1 includes an open water retaining wall constructed in conjunction with ground excavation, and a water shielding wall formed in the ground away from the retaining wall by a predetermined distance to the back side. A double retaining structure has been proposed in which the groundwater level of the ground between the impermeable walls is lowered by a deep well or the like and the ground inside the retaining wall is excavated. In this conventional example, the ground anchor does not penetrate the impermeable wall, but the ground between the retaining wall and the impermeable wall is not excavated, and the two-level mountain retaining wall in which the step excavation part is formed (the lower depth of the underground frame) Is not a double-tiered retaining wall used for underground construction of different buildings on the outer periphery and inside.

JP 2001-107361 A

The present invention examines the behavior associated with ground excavation of a two-stage mountain retaining wall in which the outer mountain retaining wall and the upper end of the inner mountain retaining wall are connected by a horizontal connecting material such as a reinforcing bar, and from the measurement results, the behavior of the outer mountain retaining wall is investigated. Is
The stress distribution can be almost evaluated by considering the effect of ground displacement due to the internal excavation of the inner retaining wall and the effect of the tensile force by the connecting rebar, and the inner retaining wall considers the ground for the two-step retaining structure as an overload. The fact that it can be almost evaluated by setting the pressure on the back side was founded, and it was made based on this new knowledge. Since excavation of the inner retaining wall is not required, support work such as ground anchors is not required. It is an object of the present invention to provide a double-stage mountain retaining wall and a method for constructing it that can reduce the work period and cost.

In order to solve the above-mentioned problems, technical measures taken by the present invention are as follows. That is,
The two-stage mountain retaining wall according to the first aspect of the present invention is a connection that can bear a tensile force between the vertical middle portion of the outer mountain retaining wall and the upper end portion of the inner mountain retaining wall that is constructed with a step excavation portion therebetween. It is characterized by being connected with materials.

A method for constructing a two-level mountain retaining wall according to claim 2 is a method for constructing a two-level mountain retaining wall according to claim 1, wherein the vertical intermediate portion of the outer mountain retaining wall and a step excavation portion inside thereof. After connecting the upper end of the inner retaining wall constructed with a gap between the upper ends of the inner retaining wall with a connecting material capable of bearing a tensile force, the inner ground of the inner retaining wall is excavated.

In addition, in the construction method of the two-stage mountain retaining wall according to claim 2, there are a case where the outer mountain retaining wall is newly established and a case where an existing mountain retaining wall is used.

The invention according to claim 3 is the former case, and is the method for constructing the two-stage retaining wall according to claim 2, wherein after the outer retaining wall is constructed, the inner ground of the outer retaining wall is used as the inner retaining wall. After excavating to the upper end level of the outer retaining wall, connecting the upper middle part of the outer retaining wall and the upper end of the inner retaining wall with a connecting material capable of bearing a tensile force, then excavating the inner ground of the inner retaining wall Yes.

The invention described in claim 4 is the latter case, and is a method for constructing a two-stage retaining wall according to claim 2, wherein a step excavation portion is provided in the vertical middle portion of the existing outer retaining wall and the inner side thereof. It is characterized by excavating the inner ground of the inner mountain retaining wall after connecting the upper end portion of the inner mountain retaining wall constructed with a gap with a connecting material capable of bearing a tensile force. In this case, as in the embodiment described in 請 Motomeko 5, connected by welding or the like core material of the reinforcing reinforcement and the inner earth retaining wall of slaughtered existing building foundation bottom plate
However, the foundation floor of the existing building that has been demolished can be used as a connecting material that can bear the tensile force .

According to invention of Claim 1, 2, since the upper end part of an inner side retaining wall is connected with the up-down direction intermediate part of the outer side retaining wall by the connection material which can bear tensile force, a deformation | transformation of an inner retaining wall is carried out. The inner ground of the inner retaining wall can be excavated while restrained, and no support work such as ground anchors is required when excavating the inner retaining wall, so the excavation work can proceed smoothly, shortening the construction period and reducing costs .

In addition, since ground anchors are not required when excavating the inner retaining wall, the anchoring part of the ground anchor cannot penetrate the outer retaining wall as a water-impervious wall and cannot secure water sealing, or the anchoring part of the ground anchor Occurrence of the problem that the core material of the retaining wall interferes and the design of the core material length is restricted can be avoided.

As the connecting material, various specifications such as rebar, steel frame, reinforced concrete can be selected as long as it can bear the required tensile force. For example, the inner and outer mountain retaining walls are connected with rebar and concrete. To increase the rigidity of the reinforced concrete structure, and streamline the retaining by using this reinforced concrete connecting material as a reinforced concrete passage or floor located at the step excavation between the inner and outer retaining walls. Can do. Also, by designing and constructing the outer and inner retaining walls as a single retaining wall, the vertical length of the outer retaining wall can be reduced, as in the case of designing and constructing each independently. It is economical because it can avoid excessive overspec (excessive quality).

According to the invention described in claim 3, the construction of the outer retaining wall, the formation of the step excavation part by excavating the inner ground of the outer retaining wall to the upper end level of the inner retaining wall, and the connecting material capable of bearing the tensile force. The two-stage mountain retaining wall according to claim 1 can be constructed by a procedure such as connection of the vertical intermediate portion of the outer mountain retaining wall and the upper end of the inner mountain retaining wall, and excavation of the inner ground of the inner mountain retaining wall.

According to the invention of claim 4, since the existing mountain retaining wall is used as the outer mountain retaining wall,
When dismantling the existing building and constructing a new building (a building where the depth of the lower part of the basement is different from that of the outer periphery and the inside), the construction process and cost of the outer retaining wall will be omitted. Economical.

In particular, according to the invention described in claim 5, it is dismantled as a connecting material capable of bearing a tensile force that connects the vertically middle portion of the outer retaining wall and the upper end portion of the newly constructed inner retaining wall. It is more economical because it uses the foundation floor of existing buildings.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a two-level mountain retaining wall. In FIG. 1, reference numeral 1 denotes an outer mountain retaining wall, and 2 denotes an inner mountain retaining wall constructed inside the outer mountain retaining wall 1 with a step excavation part 3 therebetween. As the outer mountain retaining wall 1 and the inner mountain retaining wall 2, an underground continuous wall, a column wall, a main pile horizontal sheet pile wall and the like can be selected as appropriate. However, in the illustrated example, since the groundwater level L is high, the outer mountain retaining wall 1 is blocked. A soil cement column wall having high water stopping performance is adopted as the outer mountain retaining wall 1 so as to be a water wall, and a parent pile horizontal sheet pile wall is adopted as the inner mountain retaining wall 2. 1a is a core material (for example, H steel) and 2a is a core material (for example, H steel) to be a parent pile.

The intermediate portion in the vertical direction of the outer mountain retaining wall 1 and the upper end portion of the inner mountain retaining wall 2 are connected by a connecting member 4. As the connecting material 4, various specifications such as a reinforcing bar, a steel frame, and a reinforced concrete can be selected as long as it can bear the required tensile strength. In this example, the connecting material 4
As shown in Fig. 3, one end of the reinforcing bar is bent at a right angle,
The bent portion is welded to the center of the flange of the core material 1a, and the other end of the reinforcing bar is welded to the web of the core material 2a. The connecting material (reinforcing bar) 4 is provided for each core material 2 a that becomes the parent pile of the inner mountain retaining wall 2. Reference numeral 5 denotes concrete placed in a state in which the connecting material 4 is embedded, and protects the connecting material 4. The connecting member 4 can be made of reinforced concrete, and can also be used as a reinforced concrete passage or floor located in the step excavation part 3 between the inner and outer retaining walls 1 and 2.

The outer retaining wall 1 is supported by connecting the holding piles 6 and tie rods 7 placed on the outer side thereof. However, a supporting method of a cut beam type may be selected, and the lateral resistance of the outer retaining wall 1 is reduced. If it is sufficiently large, these support works may be omitted.

FIG. 2 shows another embodiment of the present invention. This two-stage mountain retaining wall has a groundwater level L that is not so high, and even if there is spring water, the spring water can be drained by forming a drainage groove in the step excavation part 3. It is characterized in that a plate wall is used and a soil cement column wall is used as the inner mountain retaining wall 2. Since other configurations are the same as those of the embodiment of FIGS. 1 and 3, the same components are denoted by the same reference numerals and description thereof is omitted.

According to said structure, since the upper end part of the inner side retaining wall 2 is connected with the up-down direction intermediate part of the outer side retaining wall 1 by the connection material 4, the deformation | transformation of the inner side retaining wall 2 is suppressed. Since the internal ground can be excavated and no support work such as ground anchors is required when excavating the inner retaining wall 2, the excavation work can be carried out smoothly, and the construction period can be shortened and the cost can be reduced.

In addition, since the ground anchor is not required when excavating the inner retaining wall 2, the anchoring portion of the ground anchor cannot pass through the outer retaining wall 1 as a water-impervious wall and cannot secure water sealing, or the anchoring portion of the ground anchor. And the core material 1a of the outer mountain retaining wall 1 can interfere with each other, thereby avoiding the problem that the design of the core material length is restricted.

By designing and constructing the outer retaining wall 1 and the inner retaining wall 2 as an integral retaining wall,
It is possible to reduce the vertical length of the outer mountain retaining wall 1, and it is economical because it is possible to avoid overspec (excess quality) as in the case of designing and constructing each independently.

FIG. 4 shows a construction method of the two-stage mountain retaining wall shown in FIGS. 1 and 2. After the outer mountain retaining wall 1 is constructed as shown in FIG. 4A, the inner ground of the outer mountain retaining wall 1 is Excavation to the upper end level of the inner mountain retaining wall 2 to form a step excavation portion 3, and as shown in FIG.
1 and the upper end of the inner retaining wall 2 are connected by the connecting member 4, and then the inner ground of the inner retaining wall 2 is excavated as shown in FIG. The two-level mountain retaining wall shown in Fig. 2 is constructed. The inner retaining wall 2 is usually constructed after the formation of the step excavation part 3,
It is also possible to create the outer ground retaining wall 1 prior to excavation of the internal ground.

FIG. 5 shows another construction method for constructing the two-level mountain retaining wall shown in FIGS. 1 and 2. This construction method is characterized in that an existing mountain retaining wall is used as the outer mountain retaining wall 1. That is, as shown in FIG. 5A, the existing mountain retaining wall a is used as the outer mountain retaining wall 1 by dismantling and removing the existing building 8 while leaving the existing retaining wall a. If there is, the inner ground of the outer mountain retaining wall 1 is excavated to the upper end level of the inner mountain retaining wall 2 to form a step excavation part 3.
Next, as shown in FIG. 5B, the vertical intermediate portion of the outer retaining wall 1 and the upper end portion of the inner retaining wall 2 are connected by a connecting member 4, and then as shown in FIG. Then, the inner ground of the inner mountain retaining wall 2 is excavated to construct the two-stage mountain retaining wall shown in FIGS.

According to this configuration, since the existing mountain retaining wall a is used as the outer mountain retaining wall 1, the existing building 8 is dismantled and a new building (a building in which the depth of the lower part of the underground frame is different between the outer periphery and the inside) is constructed. In this case, the construction process and cost of the outer retaining wall 1 are omitted, which is very economical.

FIG. 6 shows another construction method for constructing the two-level mountain retaining wall shown in FIGS. 1 and 2. This construction method is characterized in that the existing mountain retaining wall a is used as the outer mountain retaining wall 1 and the foundation bottom b of the existing building 8 is used as the connecting member 4. That is, as shown in FIG. 6A, by dismantling and removing the existing building 8 while leaving the existing mountain retaining wall a and the foundation bottom b, the existing mountain retaining wall a becomes the outer mountain retaining wall 1. 6B, as shown in FIG. 6B, the inner retaining wall 2 is constructed so as to penetrate the foundation bottom b, and the reinforcing bars of the foundation bottom b and the core material 2a of the inner retaining wall 2 are used.
Is used as a connecting member 4 that connects the vertical intermediate portion of the outer mountain retaining wall 1 and the upper end portion of the inner mountain retaining wall 2, and the like. ,
As shown in FIG. 6C, the inner ground of the inner mountain retaining wall 2 is excavated to construct the two-stage mountain retaining wall shown in FIGS.

According to this configuration, not only the existing mountain retaining wall a is used as the outer mountain retaining wall 1, but also the foundation bottom b of the existing building 8 is used as the coupling material 4, so the process of the coupling material 4 is omitted or simplified. It will be more economical.

Although the embodiment of the present invention has been described based on FIGS. 1 to 6, the present invention is not limited to the illustrated configuration, and can be implemented in various modes without departing from the gist of the present invention. Of course you can.

It is a vertical side view of a two-level mountain retaining wall showing an embodiment of the present invention. It is a vertical side view of the two-level mountain retaining wall which shows other embodiment of this invention. FIG. 5 is a longitudinal side view of a main part illustrating a method of connecting a core material and a connecting material of inner and outer retaining walls. It is explanatory drawing of the construction method of the two-stage mountain retaining wall which shows one Embodiment of this invention. It is explanatory drawing of the construction method of the two-stage mountain retaining wall which shows other embodiment of this invention. It is explanatory drawing of the construction method of the two-stage mountain retaining wall which shows other embodiment of this invention. It is a vertical side view of the two-level mountain retaining wall explaining the problems of the prior art.

DESCRIPTION OF SYMBOLS 1 Outer mountain retaining wall 2 Inner mountain retaining wall 3 Step excavation part 4 Connecting material a Existing mountain retaining wall b Foundation bottom of existing building

Claims (5)

A two-stage mountain retaining structure characterized in that an intermediate portion in the vertical direction of the outer retaining wall and an upper end portion of the inner retaining wall constructed with a step excavation portion inside are connected by a connecting material capable of bearing a tensile force. wall. A method for constructing a two-stage retaining wall according to claim 1, wherein a tensile force is applied between an intermediate portion in the vertical direction of the outer retaining wall and an upper end portion of the inner retaining wall that is constructed with a step excavation portion inside. A method for constructing a two-level mountain retaining wall, wherein the inner ground of the inner mountain retaining wall is excavated after coupling with a burdenable coupling material. 3. The method for constructing a two-level retaining wall according to claim 2, wherein after the outer retaining wall is constructed, the inner ground of the outer retaining wall is excavated to the upper end level of the inner retaining wall, and the intermediate portion in the vertical direction of the outer retaining wall. A method for constructing a two-stage mountain retaining wall, comprising: excavating an inner ground of the inner mountain retaining wall after coupling the upper end portion of the inner mountain retaining wall with a coupling material capable of bearing a tensile force. The method for constructing a two-stage retaining wall according to claim 2, wherein a tensile force is applied between an intermediate portion in the vertical direction of the existing outer retaining wall and an upper end portion of the inner retaining wall that is constructed with a step excavation portion therebetween. A construction method of a two-stage mountain retaining wall characterized by excavating the inner ground of the inner mountain retaining wall after being coupled with a coupling material capable of bearing a load. Connect the reinforcing bars of the foundation bottom of the demolished existing building and the core material of the inner retaining wall by welding etc.
The method for constructing a two-level mountain retaining wall according to claim 4, wherein a foundation floor of an existing building that has been demolished is used as a connecting material capable of bearing a tensile force.

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