JP2011247059A - Reinforcement method for bridge abutment and back fill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reinforcement method for a bridge abutment and a back fill of the bridge abutment, while maintaining the traffic state of railroads and vehicles.SOLUTION: Back fills of the side faces of the bridge abutments are excavated along the both side faces of the bridge abutments. Rod-like reinforcement members are placed to the wall faces of the excavated back fills. Side face reinforcement blocks are placed on the both side faces of the bridge abutments in a state of receiving reaction forces from the rod-like reinforcement members. In addition, fill reinforcement walls are constructed on the outside of the existing fill retaining walls in the skirt pats of the back fills.

Description

The present invention relates to a method for reinforcing an abutment and a backfill.
More specifically, the present invention relates to a method for reinforcing a railroad abutment and a road abutment constructed with a backside embankment structure.

There are many railway abutments and road abutments with back embankment on the back.
Among these abutments, there are also structures that have problems with seismic resistance according to the current design standards.
Even if this is not the case, it is possible that the safety of the abutment and the bridge girder has deteriorated.
As a method for reinforcing such abutments and bridge girders, the following methods have been conventionally employed.
<1> A method of constructing a new structure by constructing a temporary line separately from the abutment to be repaired and removing the aged abutment and bridge girder in order to secure the use of railways and roads.
<2> A method of reinforcing aged abutments by constructing a temporary line separately.
<3> A method of repairing the abutment by winding a steel plate or installing a new wall on the abutment.

JP 2009-256938 A.

The above-described conventional abutment and back embankment reinforcement methods have the following problems.
<1> Regardless of the method of construction, there will be times when rail and vehicle traffic will be impossible, affecting the surrounding economic activities.
<2> Construction of a temporary line is a large-scale construction, resulting in an extra huge cost.
<3> In the case of railroads, there is a situation where it is not used at night, but even when reinforcement work is performed using that time, the work must be divided into short periods of time, which is uneconomical. is there.
<4> If the abutment is momentarily separated from the back embankment due to vibration during an earthquake, the back embankment may be pushed out into the gap and the abutment may not return to its original position. It has been reported that when this phenomenon is repeated, the back embankment on the back of the abutment has subsided nearly 1 meter.
<5> Therefore, even if only the abutment is reinforced, there is a possibility that it will lead to a major accident if the abutment and the back embankment are not integrated, as in the case where the back embankment sinks greatly.

In order to solve the above-described problems, the abutment and back embankment reinforcement method of the present invention includes a back embankment on the side of an abutment that has a back embankment on the back and supports the abutment, and a bridge girder along both sides of the abutment. Drilled in a direction parallel to the axial direction of the bridge girder, a bar-shaped reinforcing material was placed in parallel to the axial direction of the bridge girder on the newly excavated surface in a direction perpendicular to the axial direction of the bridge girder formed by drilling. Side reinforcement blocks are placed on both sides of the abutment in a state where force can be taken, and the side reinforcement blocks and the abutment are integrated via post-installed anchors, and stone masonry surrounding the back embankment, etc. An abutment constructed by constructing a bank reinforcing wall outside the existing bank retaining wall in a state where a bar reinforcing material is placed on the existing bank retaining wall from the surface and a reaction force can be applied to the bar reinforcing material. And the back embankment reinforcement method.

Since the abutment and back embankment reinforcement method of the present invention is as described above, one of the following effects can be obtained.
<1> The abutment and back embankment can be reinforced without installing temporary lines while ensuring the passage of railways and roads.
<2> Since the rod-shaped reinforcing material is installed and the abutment is supported via the side reinforcing blocks, the resistance of the abutment during earthquake is greatly improved.
<3> Since the abutment, the side reinforcement block, and the back embankment are integrated via a bar-shaped reinforcement placed in the back embankment, the back embankment on the back of the abutment behaves in an integrated manner even during an earthquake. Sinking is unlikely to occur.

Explanatory drawing of the abutment and back embankment before reinforcement. Explanatory drawing of the state which excavated the side surface of the abutment in parallel with the bridge axis. The top view of the state which excavated the side surface of the abutment in parallel with the bridge axis, and cast the rod-shaped reinforcement. Explanatory drawing of the state which built the side reinforcement block on the side of the abutment and reinforced the abutment and the back embankment. Explanatory drawing of the state which laid the rod-shaped reinforcement from the outside of the existing embankment retaining wall. Explanatory drawing of the state which formed the embankment reinforcement wall in the outer side of the existing embankment retaining wall. The top view of the arrangement | positioning state of a rod-shaped reinforcement. Sectional drawing of the state which reinforced the back embankment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

<1> Precondition. (Figure 1)
As described above, the object of the reinforcing method of the present invention is a method for reinforcing the abutment 1 having the back embankment 3 on the back surface and the back embankment 3.
The abutment 1 is made of concrete, and bridge girder 2 such as a road and a railroad is bridged over two abutments 1 facing each other across a road.
On the back of both sides of the abutment 1, there is a back embankment 3, and the bottom of the back embankment 3 is surrounded by existing embankment retaining walls made of masonry or concrete.
In this specification, for the convenience of explanation, for the abutment 1 having a substantially rectangular plan view, the back embankment 3 side is referred to as “rear surface”, the passage side is referred to as “front surface”, and both sides parallel to the bridge girder 2 are referred to as “side surfaces”. I will call it.

<2> Excavation of backfill. (Figure 2)
The back embankment 3 on the side surface of the abutment 1 and a part of the back embankment 3 behind it are excavated.
This excavation position is outside the roadbed of the railway or the road in a plan view.
Therefore, it does not affect the traffic of trains and vehicles.
The excavation position varies depending on the state of the back embankment 3 on the side of the abutment 1, but the excavation position is excavated along the both side surfaces of the abutment 1 in a direction parallel to the axial direction of the bridge girder 2. (Figure 2)

<3> Placing a rod-shaped reinforcing material. (Figure 3)
A rod-shaped reinforcing material 4 is driven in parallel to the axial direction of the bridge girder 2 on the newly excavated surface 5.
As this rod-shaped reinforcing material 4, a well-known construction method described in, for example, Japanese Patent No. 2575329 can be adopted.
This patent method is a method using an excavation stirring rod provided with an excavation blade and a stirring blade around a hollow rotating shaft.
The excavation stirring rod forms a mixture of cylindrical stirring soil and cement milk in the ground.
A central reinforcing body made of cement milk is located at the center of the mixture.
In the center of the central reinforcing column, a core material with the tail end exposed outside the hole is positioned, and this core material is used as a tension reinforcing body.
However, this construction method is an example, and various other known rod-shaped reinforcing materials 4 can be employed.
As shown in FIG. 3, a plurality of the rod-shaped reinforcing members 4 are driven into the backfill 3 from the newly excavated surface 5 almost parallel to the axial direction of the bridge girder 2.
Alternatively, it can be placed in the back embankment 3 at an angle from the newly excavated surface 5 toward the track center.

<4> Construction of side reinforcing blocks. (Fig. 4)
After the placement of the rod-shaped reinforcing material 4 is completed, the side reinforcement block 6 is constructed by placing a formwork around the excavated space and placing concrete.
In that case, the side reinforcing block 6 is constructed in a state where the reaction force is applied to the rod-shaped reinforcing member 4, and the side reinforcing block and the backfill 3 are integrated.
Further, the side reinforcing block 6 is constructed in a state of being integrated with the abutment 1.
For this purpose, a post-construction anchor is protruded from the abutment 1 and concrete is cast in a state surrounding the anchor, thereby integrating the abutment 1 and the side reinforcing block 6.
This side reinforcement block 6 is constructed in the same process for the abutments 1 on both sides.

<5> Placing a rod-shaped reinforcing material on the existing embankment retaining wall. (Fig. 5)
A bar-shaped reinforcing material is placed on the existing embankment retaining wall in a state of surrounding the bottom portion of the back embankment 3.
If the existing embankment retaining wall is masonry and individual stone blocks are unstable, mortar is injected into the back and integrated, then drilled into the existing embankment retaining wall and the back embankment on the back side to reinforce the rod Placing material.

<6> Construction of embankment reinforcement walls. (Fig. 6)
Formwork is installed on the outer periphery of the existing embankment retaining wall, reinforcing bars are placed at intervals, and concrete is placed to construct a embankment reinforcement wall.
The embankment reinforcing wall and the bar-shaped reinforcing material 4 are integrated with each other by positioning the core material of the bar-shaped reinforcing material 4 inside the concrete to be placed.
In this way, a new concrete embankment reinforcement wall integrated with the rod-shaped reinforcement 4 inside the back embankment is constructed on the outer periphery of the existing embankment retaining wall.

<7> Integration of abutment and back embankment.
As described above, the abutment 1 is integrated with the side reinforcing block 6 via the side construction post-installation anchor, and the side reinforcing block 6 is integrated with the rod-shaped reinforcing member 4 placed in the back embankment 3.
Accordingly, the abutment 1 is integrated with the back embankment 3 via the side reinforcing blocks 6.
Furthermore, the bottom portion of the back embankment 3 is surrounded by a newly constructed embankment reinforcement wall on the outside of the existing embankment retaining wall, and this embankment reinforcement wall is integrated with the bar-shaped reinforcement 4 placed in the back embankment 3. The back embankment 3 can also be integrated as a whole to ensure a stable form.

1: Abutment 2: Bridge girder 3: Back embankment 4: Bar-shaped reinforcement 5: New excavation surface 6: Side reinforcement block

Claims (1)

The back embankment on the side of the abutment that has the back embankment on the back and supports the bridge girder,
Drilling along the sides of the abutment in parallel with the axial direction of the bridge girder,
On the new excavation surface in a direction perpendicular to the axial direction of the bridge girder formed by excavation, a rod-shaped reinforcing material is placed in parallel with the axial direction of the bridge girder,
Side reinforcement blocks are placed on both sides of the abutment in a state where reaction force can be applied to this bar-shaped reinforcement.
The side reinforcement block and the abutment are integrated through a post-construction anchor projecting from the abutment,
Furthermore, rod-shaped reinforcing materials are placed on the existing embankment retaining walls such as masonry surrounding the back embankment from the surface,
In a state where reaction force can be taken on this bar-shaped reinforcing material, on the outside of the existing embankment retaining wall, a embankment reinforcing wall is constructed and configured.
Reinforcement method of abutment and back embankment.

Images