JPS59102009A - Method for dynamic shearing test at site of ground - Google Patents

Abstract

PURPOSE:To simply and exactly measure the dynamic both-side shearing force of a construction site by a method in which a test specimen is projectionally formed in contact with the ground, an oil-pressure cylinder is attached to the test specimen, and the test specimen is alternately pressed to detect shearing stress by a load detector. CONSTITUTION:A test specimen GE is projectionally formed connectedly to the ground TG in a site inside a tunnel T, and a static load is applied to the test specimen from bove. Oil-pressure cylinders 1 and 2 and load detectors 4 and 5 also set in the left and right-handed horizontal directions of the test specimen. The oil-pressure cylinders 1 and 2 are alternately driven through a servo amplifier (not illustrated) to press the test specimen GE, and both-side shearing forces are detected by the load detectors 4 and 5. Dynamic both-side shearing forces can be detected simply and exactly as in the case of earthquake.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for testing the dynamic shear stress of a sample produced and formed by cutting the peripheral side with the ground connected in situ, for example in a tunnel. Further details ζ2 relate to the in-situ dynamic ground shear test method for determining the strength against the dynamic shear force applied to the ground during an earthquake.

Conventionally, the nflr of the sample was applied by applying pressure from one direction.
Although methods for testing stress are known, to the best of the inventor's knowledge, a method for testing stress against dynamic oscillating shear force has not yet been proposed.

(Note: Since more than 10 years ago, the inventor has been constantly reviewing the literature in this field at home and abroad.) In order to obtain the strength that can be applied with a smaller foreshadowing of the stress function while giving the same dynamic oscillating shear force as during an earthquake, we used the 1754 day test specimen method for dynamic ground shear in situ. It is on offer.

Another object of the present invention is to provide a +
L! ! + To provide a method for an in-situ dynamic ground shear diagnosis valve test in which the accurate number 1ffi can be determined by simple means without the need for a rigid jig.

Next, an embodiment of the present invention capable of achieving the above object will be described in detail with reference to the accompanying drawings.

In FIG. 7, / and - represent plunger /a.

2a is a horizontal hydraulic cylinder, 3 is a vertical hydraulic cylinder with plunger 3a (for providing static overload), ! , B is plunger/a,,
2a, Jal: Attached 7t (for example, by screwing means)
The charge detectors, Hiroa, Ta, and 4a indicate suppression plates installed at the tips of the charge detectors g, t, and Otsu, and each hydraulic cylinder/
, C, 3 has a flange /b at its base.

,2b,,,? b is formed.

T is the tunnel, TG is the ground inside the tunnel T, GE is the ground d
This shows a sample manufactured by cutting the circumferential side while connected to TG, and the sample GE is front, rear, left and right! θ saw.

Shima! It is formed at θα. (Note: In principle, the values for front, rear, left, and right are not limited to 1, and the height can be changed arbitrarily.) 2 indicates a concrete casing with bank height/θ sub, and this casing 7 is the sample. It is fitted on the circumferential side from the top of the GE.

♂ is the left and right g of the tunnel T at the location where the horizontal hydraulic cylinder/2 and the vertical hydraulic cylinder 3 are held.
The concrete sheet supports cast on Ta and the ceiling wall Tb are shown, and each hydraulic cylinder /,,2
．． 3 flanges/a, , 2a.

3a is fixed with a bolt /θ via an iron plate.

// is a contact plate fixed on the casing gate, 7.2 is a contact plate fixed to the suppression plate a of the vertical hydraulic cylinder 3,
/3 indicates a plurality of rollers (round rods) inserted between the contact plates //, /2, and 2, and these contact plates //, /2 and rollers /3 cause the sample GE to be subjected to vertical pressure by the plunger 3a. It is constructed so that no horizontal pressure is applied.

In addition, the horizontal hydraulic cylinder 7 is controlled by a hydraulic servo system with cargo position feedback to prevent surges when changing the oil flow path, and is driven by a human power signal, as shown in the block diagram of Figure 1. Input signal AF
, servo amplifier 8A.

Servo pulp SV, hydraulic cylinder/, 2. Charged detector! , and a load amplifier LA.

Under the above conditions, the vertical hydraulic cylinder 3 applies a static overloading storm to the sample GE, and the horizontal hydraulic cylinder 2 lightly pushes the sample GE, while the horizontal hydraulic cylinder 2 presses the sample GE lightly.

- is driven by one half wave of a sine wave as shown in [) (II) in FIG. 3 by the input signal AF, and the sample GE is pressed alternately from the left and right sides. (F indicates the compressive force of the sample GE.) In that case, the shear force applied to the sample ([ is shown in (1). (tm indicates the timeline.) And now, the horizontal Assuming that the directional hydraulic cylinders /, ko and the vertical hydraulic cylinders 3 generate outputs of j0TOH, sample cross-sectional area m=!θxj0=, Ltθθcr11″ vertical stress =--) - in case λθ mark f/♂ shear stress =,
2θQlf/cm” - Modulus of shear elasticity: G-!- [幀/♂] Attenuation constant “ ” 〆πW In the figure, 'tAa,, is =!Oxjθ=, 2!θθcrn1 t=3!□□□ Δt =ooz mouth F=J-0000 Therefore, it becomes.

Since the present invention is constructed as described above, it is possible to perform tests while alternately applying dynamic shear forces similar to those during an earthquake, and to obtain a strength that can be applied to a sample with a small stress function. There is no need for a fixing jig to apply tensile force, and therefore, accurate numerical values can be obtained using the attached means.

[Brief explanation of drawings]

FIG. 7 is used in the method of the present invention! Conceptual diagram of A location,
Fig. 1 is a block diagram of the output from the human input signal, Fig. 3 is an output waveform chart, and Fig. 1 and 1 are explanatory diagrams of numerical value detection. T...Tunnel, TG...Ground, GE...Sample A
F...Input signal, 8A...Servo amplifier-...Left and right horizontal hydraulic cylinders,! ...Load detector-39=

Claims (1)

[Claims] At the original location such as in a tunnel, the sample is connected to the ground to form a protrusion, and a static overload is applied to the sample, while the left and right horizontal hydraulic cylinders ζ; While pushing the sample more lightly, the left and right horizontal hydraulic cylinders This is achieved by alternating left and right vibrations via a servo amplifier in response to an input signal, pressing the sample alternately from the left and right sides, and detecting the shear stress with a load detector. U9g concubine prayer test crystal method.