JPS59185225A - Stabilization work of slope by anchor rod - Google Patents

Abstract

PURPOSE:To raise the safety of soil degradation by determining the number of anchor rods to be driven and the shape of cross section from measured values of bending stress and shearing stress to be received by the anchor rods driven in the slope ground. CONSTITUTION:Plural anchor rods 5 are driven into a graded slope ground 1 where the degradation of soil lumps 4 could occur. The ends of the ground surface are connected in a tensed state by a connector 6, e.g., turnbuckle, etc., and by the clamping force, the portion near the surface of the sloped ground is fixed to prevent small degradation of soil. Strain guages are attached to the places corresponding to points A and B at which the axes of the anchor rods and landslide face 3 are crossed with each other. Bending stress and shearing stress acting on the points A and B of dispersion load DELTAP(=P/2) to be received by the anchor rods 5 are exactly and quickly measured by measurers provided on the outside in order to determine the number of rods to be driven and cross section and shape of the rods.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved construction method for preventing the collapse of a soil slope by driving an anchor rod into the soil slope.

[Prior Art] Conventionally, as a construction method for preventing landslides or other collapses of soil slopes created by cutting or filling, a method of driving anchor holes on soil slopes is known. However, since this method simply places each anchor rond independently, each anchor rond faces the soil mass individually, and is not necessarily effective in preventing collapse.

As a result of research in order to increase the effect of preventing collapse, the present applicant has found that if the tips of the anchor ronds are connected in a tight state with a connecting tool, the connected anchor ronds will come together to face the soil mass, and as a result, collapse will be prevented. He discovered that the effect could be significantly improved and filed a patent application in 1984-4640.
Disclosed in issue 7. However, because the number of anchor ronds to be cast and the cross-sectional shape were determined only based on past experience and experimental formulas, the safety of preventing collapse was insufficiently confirmed.
In addition, an unnecessarily large number of anchor ronds were required to be cast, leading to an increase in construction costs.

[Purpose of the invention]

The present invention aims to solve the problems of the prior art, and can significantly improve the stability of soil slopes, as well as improve the safety of preventing collapse by selecting anchor rods with an appropriate number and cross-sectional shape. The purpose of the present invention is to provide a slope stabilization method that can significantly increase the slope stability and reduce construction costs.

[Structure of the invention]

In order to achieve the above object, the present invention is configured to measure the bending stress and shear stress exerted on the buried portion of the anchor rod by the soil clod, and thereby determine the number and cross-sectional shape of the anchor rod.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to an embodiment shown in the attached drawings.

FIG. 1 shows a constructed ground (2) having a soil slope (1), and (3) in the figure is a slip surface where the soil mass (4) may collapse.

In the above-mentioned prepared ground (2), the anchor rod (5) according to the present invention is driven into the soil slope (11) so that its axis is perpendicular to the above-mentioned sliding surface (3). (5) has its ground surface end connected in tension by a connector (6) such as a turnbuckle.In this configuration, the soil mass (4) is now connected to the sliding surface (
Assume that the building is about to collapse downward along 3). In this case, first the anchor rod (5).

(5) are connected in a tightened state by the connector (6), so that the portion near the slope surface is fixed by the tightening force and small collapse can be prevented. Also, the load (P
) is anchor rod f51. (51 is connected with the connector (6), so the anchor rod (5), (5
1 receives a distributed load of ΔP (=P/2), and this distributed load ΔP is applied to the sliding surface (3) and the anchor rod (5).
) substantially acts on the points (A) and (B) where the axes intersect. This allows for example the anchor rod (5)
The distance from the tip to the intersections (A) and (B) is p/
3 (where β is the total length of the anchor rod (5)), the anchor rod (5) bends as shown by the dotted line and receives a bending moment M (-Δp x n / 3 ). On the other hand, a distributed load ΔP further acts on the anchor rod (5) as a shearing force at the intersections (A) and (B). From this, bending stress σ (=M/Z, where Z is the section modulus of the anchor rod (5)) and shear stress τ (-ΔP/S, here S is the section modulus of the anchor rod (5)) in the anchor rod (5). cross-sectional area) occurs. The bending stress σ and shear stress τ can be determined by installing strain gauges (not shown) at the intersections (A, ) and (B) of the anchor rod (5), and measuring the values of the strain gauges externally. It can be easily obtained by measuring with a measuring instrument.

Based on this data, the number of anchor rods (5) to be installed and the cross-sectional shape such as the diameter are determined. In this case, the above determination is made by taking the larger of the bending stress σ and the shearing stress τ.

Note that various forms of connection of the anchor rod (5) are possible, examples of which are shown in Figs. 2, 3, and 4.
As shown in the figure. Figure 2 shows two anchor rods (5) and a third
The figure shows a case in which 3' anchor rods (5) are connected, and FIG. 4 shows a case in which four anchor rods (5) are connected.

〔Effect of the invention〕

As described above, the method for stabilizing slopes using anchor rods according to the present invention allows the bending stress and shear stress applied to the anchor rods to be accurately and quickly determined, so that it is possible to accurately and quickly determine the number of anchor rods to be installed, their diameter, etc. The cross-sectional shape can be determined quickly, construction work can be carried out quickly, and sufficient safety can be ensured to prevent collapse.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a slope stabilization method using an anchor rod according to the present invention, and FIGS. 2 to 4 are explanatory diagrams of a state in which the anchor rods are connected. In the figure: (1): soil slope (2); constructed ground (3): slip surface (4): soil clod (5): anchor rod (6): connection odor

Claims (1)

[Claims] 1. Place multiple anchor ronds regularly or irregularly on the soil slope so that their axes are approximately perpendicular to the direction in which the soil clod load acts, and connect the surface ends of the anchor ronds with a connecting tool. The anchor iron is connected in a tensioned state, and the bending stress and shear stress that the anchor iron receives due to the earth clod load are measured from the outside, and the cross-sectional shape of the anchor iron and the number of anchor irons to be cast are determined based on the measured values. Slope stabilization method.