JPH0796779B2 - Construction method of slope protection structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a construction method for a structure in which a formwork is assembled on a slope and a cement-based hardening material is placed to prevent the slope from collapsing. is there.

(Prior Art) A method is adopted in which a mold is assembled on the slope and a cement-based hardening material is cast to construct a structure, and the ground is stabilized by this structure.

Such a structure is fixed to the natural ground by an anchor, but as shown in FIG. 9, first, an anchor a is driven only in the middle of the structure to be constructed in the width direction, and the weir is anchored at this anchor a. A method has been adopted in which a spacer c that holds the space between the plates b and b is bound by a binding line and the formwork is installed in the ground.

(Problems to be solved by the present invention) According to the method as described above, the spacers only maintain the distance between the weir plates and do not have rigidity as a structural material, and the spacers easily bend. Will end up. With such a method of fixing to the anchor via the spacer, although the anchor was placed, the spacer is bent or damaged, and the weir plate is displaced or the curing material is sprayed. In some cases, the weir plate moved due to pressure and the structure as designed could not be constructed.

Further, since the spacer and the anchor are simply connected by a binding line, loosening the binding causes a problem that the mold frame is easily displaced to the left and right. Further, when the width direction of the structure is the inclination direction of the slope as shown in the figure, the overturning moment Ma acts with the contact point with the ground on the lower side in the width direction of the structure as the fulcrum A. In order to fix the structure to the ground, the resistance moment Mb in the opposite direction that balances this moment Ma
It is necessary to generate this resistance moment
Mb is determined by the pull-out resistance P of the anchor and the distance from the fulcrum A to the anchor.

In the case of FIG. 9, the distance between the anchor and the trough side of the structure is L / 2 when the width of the structure is L, and the distance from the fulcrum A to the anchor is L / 2, and the resistance moment Mb is from the fulcrum. Since it is the product of the distance and the pull-out resistance P of the anchor, Mb =
It becomes L / 2 x P.

That is, in order to obtain the resistance moment Mb that balances the overturning moment Ma, a large pull-out resistance force P is required because the distance from the fulcrum A is short. In this way, the width of the bent structure is L
However, the anchor struck in the middle of the width direction requires a large pull-out resistance force P for the anchor because the distance from the fulcrum A is small, and sometimes a pull-out resistance force P that exceeds the performance of the anchor is required. Becomes When a force that exceeds the performance of the anchor is required in this manner, the situation may occur in which the anchor cannot be withstood and comes off.

The present invention has been made to solve the above problems, and a method for constructing a slope protection structure that can firmly install the structure on the ground and can achieve long-term stability of the slope. The purpose is to provide.

(Means for Solving the Problem) The construction method of the slope protection structure according to the present invention is to place anchors along both sides in the width direction of the structure to be constructed.

The anchors to be placed on both the left and right sides are to be placed with a plurality of them spaced apart at appropriate intervals, and the anchors on the other side are alternately arranged between the anchors on either the left or right side. . Some of the anchors are projected above the ground. Reinforcing bars, steel rods, or rock bolts can be widely used as the anchor.

Reinforcing bars are placed between the left and right anchors. The rebar body is composed of a plurality of main muscles and hoop muscles arranged so as to surround these outer peripheries. The rebar body bears a shearing force, and the rebar body is fixed to the anchor by a binding wire or the like.

Weir plates are arranged on the left and right sides of the rebar body along the rebar body.
A porous wire mesh material such as expanded metal or crimp wire mesh is used as the barrier plate. The use of this wire mesh material is an important requirement. It is easy to insert a spacer or the like, work is easy, and there is no problem even if it follows an anchor.
Further, the wire mesh material is easily bent, and even if the reinforcing bar is bent or the anchoring position is slightly deviated, the weir plate can easily follow the reinforcing bars along the reinforcing bar.

A cement-based hardening material is placed between the two dam plates to construct a structure. Concrete, mortar, cement milk, etc. can be used as the cement-based hardening material.

When the stiffener hardened and the structure was completed, the weir plate was placed along the reinforcing bar, so the anchors on the left and right of the reinforcing bar must be positioned just at the left and right ends of the structure. become. A very important effect can be obtained depending on the position of this anchor.

(Operation) An anchor is placed along both sides in the width direction of the structure, and the dam plate is arranged along the reinforcing bar. Therefore, as described above, the anchors are located near the left and right ends of the structure in the width direction, and the width between the left and right anchors is substantially separated by the width L of the structure.

As described above, as shown in FIG. 8, the overturning moment Ma that is about to fall acts on the structure with the contact point between the lower side of the structure and the ground as the fulcrum A. In order to prevent the structure from falling, a resistance moment Mb that balances the falling moment Ma is generated by the anchor.

Since the resistance moment Mb is the product of the distance L from the fulcrum A to the anchor on the upper side and the pullout resistance force P, the moment Mb = L × P. In other words, when the anchor is driven to the very left and right ends of the structure in the width direction, the pull-out resistance force P which is one half of the conventional case where the anchor is driven to the middle portion of the structure in the width direction is sufficient. This means that the pulling force acting on the anchor is small, and the occurrence of accidents where the anchor slips out of the ground is reduced.

This is the same as pulling out the nail by locating it near the fulcrum of the nail pulling tool as much as possible and reducing the pulling resistance moment of the nail to make it easier to pull out. A large force is required to pull it out. In the present invention, the anchor is placed as far as possible from the fulcrum so that a large pulling force does not act on the anchor.

(Example) Hereinafter, the present invention will be described in detail based on an example shown in the drawings.

4 to 6 show the assembling of the formwork in the order of construction, and the left and right of the middle two-dot chain line are shown on the same plane for the sake of convenience, but in reality either the left or right anchor is shown. And the anchor on the other side is displaced in the longitudinal direction of the form.

In the figure, 1 is an anchor. Anchor 1 in the example
The steel rod is used as. A plurality of anchors 1 are placed at right and left in the width direction of the structure to be constructed, and are spaced at appropriate intervals. In addition, the position of placement is such that the anchor 1 on the other side is located between the anchors 1 on either the left or right side. That is, the anchors 1 on both the left and right sides are arranged in a staggered manner with a distance.

The rebar body 2 is arranged between the anchors 1 on both sides. The rebar body has a plurality of main bars 3 arranged along the longitudinal direction of the structure, and their outer circumferences are surrounded by hoop bars 4. Since the rebar body 2 is located between the anchors 1 and 1, it does not shift in the width direction. The reinforcing bar body 2 is connected to the anchors 1.1 by fixing the hoop muscles 4 to the anchors 1 by binding wires.

The weir plates 5, 5 made of a porous wire mesh material are erected so as to extend along both sides of the reinforcing bar. In the example, expanded metal was used as the dam plate 5 of the wire mesh material. Since the porous wire mesh is easy to pass through the spacer and has the property of being easily bent, it is easy to follow the reinforcing bar body 2 and to perform the connecting work. Therefore, unlike a material such as wood or paper, it can be easily placed along the rebar body 2, and the anchors 1 can be easily positioned as close to the left and right as possible in the width direction of the structure. Weir board 5
5 may be bound to the anchors 1 and 1 as shown in FIG.

Between the two dam plates 5, 5, concrete 7 which is a cement-based hardening material is placed.

(Effects of the Invention) Since the present invention has the configuration as described above, the following effects can be obtained.

(A) Since the left and right weir plates are not connected to the anchor or the like via the spacer but along the rebar body with high rigidity, the left and right weir plates are constrained by the width of the rebar body, and the spacer is bent. Even if it is damaged or damaged, the position is unlikely to shift and it is possible to construct a structure as designed.

(B) Since a porous wire mesh material is used as the weir plate, the holes can be used for easy connection by a spacer, and the bendable property can be used to stand up along the reinforcing bar. it can. Therefore, regardless of the bending of the reinforcing bar or the shape of the ground, it can be made to follow the reinforcing bar body. Therefore, it is possible to inevitably position the anchor that binds along the reinforcing bar near the left and right ends of the structure in the width direction.

(C) Since the reinforcing bar is bound directly to the anchor, the reinforcing bar is not displaced.

(D) The anchors are located not at the middle of the width direction of the structure but near the left and right ends of the structure in the width direction. As shown in FIG. 8, a falling moment Ma that acts to fall the structure acts on the contact point between the lower side of the structure and the ground as a fulcrum A, but the pull-out resistance of the anchor located above the slope is Resist with force P. The position of the anchor is separated from the fulcrum A by the farthest distance L, and the pulling-out resistance force P of the anchor may be small in order to generate the resistance moment Mb that balances the overturning moment Ma. This means that the force to pull out the anchor is reduced, and the occurrence of accidents such as the anchor coming off is reduced.

(E) By arranging the left and right anchors in an alternating manner, the number of anchors can be reduced and the construction can be performed at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a construction state of the present invention, FIG. 2 is a partial vertical cross-sectional view thereof, FIG. 3 is a schematic view showing an anchoring position, and FIGS. FIG. 7 is an explanatory view showing the order of assembling, FIG. 7 is a sectional view of another embodiment, FIG. 8 is an explanatory view showing a moment acting on the structure according to the present invention, and FIG. 9 is acting on a conventional structure. It is explanatory drawing which shows a moment. 1 …… Anchor, 2 …… Reinforcing bar, 3 …… Main bar, 4 …… Hoop bar, 5 …… Weir plate, 6 …… Spacer, 7 …… Concrete.

Claims (1)

[Claims] 1. Anchors are struck in the natural ground along both sides in the width direction of a structure to be constructed, and the anchors on the other side are positioned between the anchors on either the left or right side. In this way, a reinforcing bar consisting of main and hoop muscles is arranged along the left and right anchors, and this reinforcing bar is directly bound to the left and right anchors.
Weir plates made of wire mesh material are arranged along the reinforcing bars, cement hardening materials are placed between both weir plates, and the left and right anchors are located near the left and right ends of the structure Construction method for structures.