JPH09177082A - Method of stabilizing cut earth inclined surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize a cut earth inclined surface with a good constructing efficiency by arranging a form and a reinforcement around a temporary pressure plate, spraying concrete into the form to support the natural ground integrally with the temporary pressure plate. SOLUTION: A tensile member 4 and a guide pipe 5 are inserted to the center hole 10 of a temporary pressure plate 9 to lay the temporary pressure plate 9 on a cut earth inclined surface 1. Each taper hole 24 of an anchor head 23 is inserted to the tensile member 4 protruded from a base 19, and the anchor head 23 is set on the top part of the base 19. The end parts of all the tensile members 4 are held by a jack, and stressed and fixed at once. The fixation of each tensile member 4 is performed by inserting a conical wedge 24 into the taper hole 24 of the anchor head 23. Since the stretching force introduced to the tensile member 4 is transmitted to the temporary pressure plate 9 through the base 19, the bottom surface of the temporary pressure plate 9 is strongly pressed onto the cut earth inclined surface 1, and the use of a cross temporary pressure plate allows the pressing of the natural ground in a wide area of its plane area or more.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for stabilizing a cut slope.

[0002]

2. Description of the Related Art As one of the methods for stabilizing slopes, a concrete prefabricated block is carried into the site, after the prefabricated earth anchor is inserted through the prefabricated block, the anchor top is tensioned and fixed, and a bearing block is provided. It is known to suppress the deformation of the ground by pressing it with the bearing surface.

[0003]

The collapse inhibiting force of the prefabricated block depends on the bearing area of the block. If the bearing area is increased, the weight of the prefabricated block increases and the workability deteriorates.On the contrary, if the prefabricated block is made smaller and lighter and the workability is prioritized, the collapsing deterrent force is sacrificed. I cannot meet both sex conditions. It has also been pointed out that if the anchor breaks or the tension is artificially relaxed due to re-tensioning of the anchor, the existing block may slip off. In addition, a method of constructing blocks on site is proposed, but it is necessary to wait for the anchor tension work until the strength of the concrete appears, which not only prolongs the construction period but also during concrete curing. There is a danger of slope collapse.

The present invention has been made in view of the above points, and its object is to have high construction efficiency, safety during construction and after construction, and high bearing efficiency of the ground. To provide a method for stabilizing the cut slope.

[0005]

[Means for Solving the Problems] That is, in the invention according to claim 1, an anchor is fixed to a natural ground, a temporary pressure receiving plate is fixed to the anchor exposed on the ground surface to support the natural ground, and then the temporary ground. A method for stabilizing a cut slope, which is characterized by arranging a form around the pressure receiving plate and constructing a pressure receiving structure that supports the ground integrally with the temporary pressure receiving plate. Further, the invention according to claim 2 is characterized in that, in the invention of claim 1, a guide pipe is exteriorly mounted on a neck portion of the anchor, and a protruding portion of the guide pipe is integrated with a temporary pressure receiving plate and a pressure receiving structure. It is a method of stabilizing soil slopes. According to a third aspect of the present invention, in the invention of the second aspect, the pedestal has a floor plate attached to the upper surface of the temporary pressure receiving plate, an adjustment washer attached to the floor plate, a transmission cylinder erected on the adjustment washer, and a transmission. A method of stabilizing a cut slope, which is characterized by comprising a pressure bearing plate joined to the top of a cylinder. Further, in the invention according to claim 4, in the invention according to claim 1, claim 2 or claim 3, the anchor is fixed to the temporary pressure receiving plate by interposing a pedestal having a function of adjusting an inclination angle in the temporary pressure receiving plate. Is a method of stabilizing a cut slope. Further, the invention according to claim 5 is the invention according to claim 1 or claim 2 or claim 3 or claim 4, wherein the planar shape of the temporary pressure receiving plate is a cross shape, and each side is provided with a reinforcing bar. It is a stable method of the cut slope, characterized by. Further, the invention according to claim 6 is the invention of claim 1 or claim 2 or claim 3 or claim 4 or claim 5, wherein the pressure receiving structure is a cruciform flat surface using a cruciform mold. It is a method of stabilizing cut slopes, which is characterized by being constructed in a shape.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for stabilizing a cut slope will be described with reference to the drawings. <A> Anchor work (Fig. 2) Anchor holes 2 are drilled in the cut slope 1 made by cutting in stages from the upper part of the slope along the designed cut line. Since it is difficult to drill the boring machine vertically to the cut slope 1, the anchor hole 2 is drilled obliquely to the cut slope 1. Next, after inserting the tensile member 4 such as a PC steel wire into the anchor hole 2 together with the sheath 3, a grout material 6 such as mortar is injected into the anchor hole 2 so that the tip of the tensile member 4 not shown is ground. Settle in. Before or immediately after the injection of the grout material 6, the guide pipe 5 is attached to the neck portion of the sheath 3.
And the lower half of the guide pipe 5 is embedded in the grout material 6. If the opening 7 is provided in the lower half of the peripheral surface of the guide pipe 5, the grout material 6 has continuity inside and outside the guide pipe 5, so that the guide pipe 6 can be firmly fixed. The guide pipe 5 is made of a resin cylinder or a steel pipe, and the upper half thereof is projected outward from the surface of the cut slope 1. Further, the periphery of the anchor hole 2 is flattened with a grout material 8 for repair.

<B> Laying of temporary pressure receiving plate (FIGS. 1 and 3) When the grout material is hardened, the tensioning member 4 and the guide pipe 5 are inserted into the central hole 10 of the temporary pressure receiving plate 9 to cut the temporary pressure receiving plate 9. Lay on the soil slope 1. In order to prevent the pressure bearing plate 9 from slipping off, the anchor pin 12 is driven into the pin hole 11 of the temporary pressure receiving plate 9 to temporarily fix the pressure bearing plate 9. The temporary pressure receiving plate 9 is a cross-shaped or square iron plate for temporarily holding the cut slope 1, and a reinforcing bar 13 formed by bending a reinforcing bar into a U-shape is welded to each end of the iron plate and a central hole is formed. A plurality of bolts 14 are attached to the periphery of 10. The reinforcing bar 13 has not only a function as a handle for transporting the temporary pressure receiving plate 9 but also a number of functions described later. The base plate 15, the adjustment washer 16, the transmission cylinder 17, and the pressure bearing plate 18 are stacked in this order on the upper surface of the temporary pressure receiving plate 9, and each member 15 to 18 is stacked.
The pedestal 19 is manufactured by connecting the spaces by welding or the like. The pedestal 19 is manufactured on site or in a factory or the like in advance. The pedestal 16 has a central hole 20 through which the tensile member 4 and the guide pipe 5 can be inserted, and is mounted on the tensile member 4 and the guide pipe 5,
The temporary pressure receiving plate 9 is seated. The adjusting washer 16 having a difference in wall thickness is interposed between the floor plate 15 and the transmission cylinder 17 so that the transmission cylinder 17 is substantially aligned with the inclination of the anchor hole 2 and the tension member 4 is linearly tensioned. . However, it is difficult to finely adjust the axis of the pedestal 19 exactly with the axis of the tension member 4 only with the adjustment washer 16. Therefore, the pedestal 19
Is rotated for fine adjustment, and at the position where the axis of the pedestal 19 coincides with the axis of the tension member 4, the nut 22 is attached to the bolt 14 of the temporary pressure receiving plate 9 inserted into the elongated hole 21 of the floor plate 15. Secure by screwing.

<C> Depressing the ground by the temporary pressure receiving plate (FIG. 3) Each taper hole 24 of the anchor head 23 is inserted into the tension member 4 protruding from the pedestal 19, and the anchor head 23 is set on the top of the pedestal 19. To do. Next, using a well-known tension jack (not shown), the end portions of all the tension members 4 are gripped, and the tension members 4 are simultaneously tensioned and fixed. To fix each tension member 4, a cone-shaped wedge 25 is inserted into the tapered hole 24 of the anchor head 23 and fixed. Note that the pedestal 19 is filled with anticorrosive oil, mortar, or the like to perform anticorrosive treatment on the tensile member 4. Since the tension force introduced into the tension member 4 is transmitted to the temporary pressure receiving plate 9 via the pedestal 19, the bottom surface of the temporary pressure receiving plate 9 is strongly pressed against the cut slope 1. Here, the pressing area of the natural pressure by the temporary pressure receiving plate 9 will be considered based on FIG. Of course, the flat area of the temporary pressure receiving plate 9 that directly contacts the natural ground is the pressing area, but when using the temporary pressure receiving plate 9 having a cross shape in plan view, each of the temporary pressure receiving plates 9 is used. The area surrounded by the hatching located between the plate surfaces is also the pressing area. This will be explained by taking out, for example, only two plate surfaces 9a and 9b constituting the temporary pressure receiving plate 9, and when each plate surface 9a, 9b is pressed against the ground, each plate surface 9a, 9b is pressed to the surrounding ground. The force works to push it out. This force acts on both of the adjacent plate surfaces 9a and 9b. Since these forces act as a condensing force, the ground between the adjacent plate surfaces 9a and 9b is strengthened and is in the same state as being pressed by the plate surfaces. This phenomenon occurs between the other adjacent plate surfaces 9b and 9a, between the plate surfaces 9c and 9d,
It occurs between the plate surface 9d and the plate surface 9a, respectively. Therefore, if the cruciform temporary pressure receiving plate 9 is used, it is possible to press the ground with a wide area larger than the plane area of the temporary pressure receiving plate 9.

<D> Construction of pressure receiving structure (FIGS. 1, 4, and 6) With the temporary pressure receiving plate 9 temporarily suppressing the collapse of the cut slope 1, the cross shape is formed around the temporary pressure receiving plate 9. The mold 26 having the closed shape is arranged, and the reinforcing bars 27 are arranged in the mold 26. The formwork 26 may be a conventional wood or steel panel, but is preferably made using wire mesh as shown. The reinforcing bar 13 of the temporary pressure receiving plate 9 functions as a spacer member that supports the reinforcing bar 27 while separating it from the cut slope 1. Further, the reinforcing bars 27 may be bent one by one by bending them into a U shape, but may also be arranged by a unit of horizontally dividing the reinforcing bar cage. At this time, the anchor head 23
Are positioned above the upper side of the form 26 and the reinforcing bars 27. Next, as shown in FIG. 6, concrete or mortar is sprayed into the mold 26 to construct a cross-shaped pressure receiving structure 28. In addition, before spraying concrete or mortar, it is necessary to cover the anchor head 23 with a protective cap to prevent concrete or mortar from adhering. In addition, when the mold 26 made of wire mesh is used, the mold 2
6 is buried without being demolded.

<E> Secondary tension (FIGS. 6 and 7) When the strength of the pressure receiving structure 28 is developed, a tension jack is set on the anchor head 23 exposed on the surface of the pressure receiving structure 28, and the tension member 4 is attached. Re-tensioned and fixed. The tension force introduced into the tension member 4 is transmitted to the pressure receiving structure 28 integrally formed with the temporary pressure receiving plate 9, and the pressure receiving structure 28 of the reinforced concrete structure (RC) presses the ground. As shown in FIG. 6, as for the pressing area of the pressure receiving structure 28, the peripheral portion (hatched area) where the cross-shaped pressure receiving structure 28 is not in direct contact can also be pressed. The reason for this is the same as in the case of the temporary pressure receiving plate 9 described above, and a description thereof will be omitted. Further, in FIG. 7, the reinforcing bar 13 obliquely protruding from the temporary pressure receiving plate 9 serves to more firmly integrate the temporary pressure receiving plate 9 and the pressure receiving structure 28, and the shear resistance area is increased to increase the temporary pressure receiving plate. It has the same function as expanding the area of 9. Further, when the tension force introduced into the tension member 4 is released for some reason, the temporary pressure receiving plate 9 and the pressure receiving structure 28 are supported by the guide pipe 5 that is integral with the temporary pressure receiving plate 9 and the pressure receiving plate 9. The structure 28 is prevented from falling.

[0011]

Since the present invention is as described above, the following effects can be obtained. <a> The cut slope immediately after excavation has unstable properties,
With the temporary pressure plate fixed to the anchor, it is possible to build a concrete pressure receiving structure while stabilizing the ground quickly. <B> By making the planar shapes of the temporary pressure receiving plate and the pressure receiving structure into a cross shape, it is possible to secure a large pressing area larger than the contact area of the temporary pressure receiving plate or the pressure receiving structure. Therefore, the cut slope can be efficiently stabilized. <C> Since the guide pipe is mounted on the neck of the anchor immediately after excavation, the binder can be filled with the anchor held in the axial center of the anchor hole. Therefore, the thickness of the anchor trunk can be made uniform, and the anchor's yield strength and water blocking performance can be improved. <D> When the anchor loses its tension, the protruding portion of the guide pipe can prevent the temporary pressure receiving plate and the pressure receiving structure from slipping off, and the safety during and after the construction is enhanced.
Further, since the protruding portion of the guide pipe serves as a guide member when the temporary pressure receiving plate is installed, the temporary pressure receiving plate can be accurately and easily installed. <E> Since the inclination angle of the pedestal can be adjusted with respect to the temporary pressure plate, even if there is some error in the design drive angle of the anchor,
The anchor can be fixed by eliminating these errors.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a construction method according to an embodiment of the present invention, and is a perspective view of a temporary pressure receiving plate, a mold, and a reinforcing bar.

FIG. 2 is a cross-sectional view of a cut slope showing a process from opening an anchor hole to installing a guide pipe.

FIG. 3 is an explanatory view of a support structure for a cut slope and a fixing structure of a tension member by a temporary pressure receiving plate.

FIG. 4 is a cross-sectional view of a cut slope showing steps until the pressure receiving structure is constructed.

FIG. 5 is a plane model diagram for explaining a pressing effect of the temporary pressure plate against the natural ground.

FIG. 6 is a plan model diagram for explaining a pressing effect of the pressure receiving structure on the natural ground.

7 is a sectional view taken along line VII-VII in FIG.

Claims (6)

[Claims] 1. An anchor is fixed to the ground, a temporary pressure receiving plate is fixed to the anchor exposed on the surface of the earth to support the ground, and then a form is arranged around the temporary pressure receiving plate to temporarily receive the pressure. A method for stabilizing a cut slope, which is characterized by constructing a pressure receiving structure that supports the natural ground with a plate. 2. A method for stabilizing a cut slope, according to claim 1, wherein a guide pipe is exteriorly mounted on a neck portion of the anchor, and a protruding portion of the guide pipe is integrated with the temporary pressure receiving plate and the pressure receiving structure. . 3. The pedestal according to claim 2, wherein the pedestal is attached to the top surface of the temporary pressure receiving plate, the adjustment washer attached to the laying plate, the transmission cylinder erected on the adjustment washer, and the top of the transmission cylinder. A method for stabilizing a cut slope, which comprises a pressure bearing plate. 4. The claim 1, the claim 2, or the claim 3.
2. A method for stabilizing a cut slope, comprising fixing the anchor to the temporary pressure receiving plate via a pedestal having a function of adjusting a tilt angle on the temporary pressure receiving plate. 5. The claim 1, the claim 2, or the claim 3.
Alternatively, in claim 4, the plan view shape of the temporary pressure receiving plate has a cross shape, and each side is provided with a reinforcing bar, and a method for stabilizing a cut slope. 6. The claim 1, the claim 2, or the claim 3.
Alternatively, in claim 4 or claim 5, a method for stabilizing a cut slope is characterized in that the pressure receiving structure is constructed in a cruciform planar shape by using a cruciform mold.