KR200425329Y1 - field tri axial test system - Google Patents

Abstract

The present invention provides an on-site triaxial compression test apparatus for evaluating the ground strength constant of the weathering band layer of the foundation arm, which is easily disassembled and transported and can be assembled and installed in the field. In order to make it possible, in the evaluation of the ground strength parameters for the weathering zone layer forming the ground by loading the load in the three-axis direction of the specimen formed by excavating the ground under test and measuring the deformation characteristic in each direction, the intermediate The pair consists of a pair of reaction force supporting rods arranged to cross each other, which facilitates assembly and disassembly, and a reinforcement plate is attached to the intersection of the reaction force supporting rods to reinforce the mechanical strength of the portion. The normal hydraulic jack is arranged on the lower side of the plate to load the specimen in the Z direction. The reinforcing plate is a configuration with a protrusion on a four-way corner according integrally formed, and can give to the support firmly attached to the cross-point of the reaction force support rod, each of the projections is provided a bolt for attaching the cover to the body.

Weathering band layer of foundation arm, field triaxial compression test, ground strength constant measurement,

Description

Compressor for evaluating ground constant of weathered bed layer {field tri axial test system}

1 is an exploded perspective view showing the configuration of a device according to the present invention.

Figure 2a is a view showing an example of the installation of the reaction force anchor as a foundation step for applying the device of the present invention to the ground under test.

It is a figure which shows the example which constructed the specimen and the horizontal reaction force concrete block on the test ground.

Figure 2c is a view showing an example in which the hydraulic jack for the Z direction loading on the upper surface of the specimen.

Figure 2d is a view showing an example of a three-axis compression step performed by combining the device of the present invention with the hydraulic jack.

<Description of the symbols for the main parts of the drawings>

2: reaction support rod 4: gusset

20: recess 22: long hole

40: protrusion 42: fastening bolt

44: cover 46: through

48: nut

The present invention relates to an on-site triaxial compression test apparatus for evaluating the ground strength constants for the weathering zone of foundation rocks required for civil construction.

The foundation rocks widely distributed in the domestic soil exist in the form of weathered residual soil, weathered rock, soft rock, and hard rock according to the degree of weathering, and these rocks are representative grounds that are inevitably encountered in construction work. Properties and mechanical ground strength constants are essential to the overall civil design, including excavation, shallow or deep pile foundations, fills, and cuts.

However, in the case of weathered zone, unlike soil soils, the strength characteristics depend on the condition of the discontinuous surface of the rock. Therefore, it is difficult to evaluate the internal dynamics test on small specimens. Therefore, it is necessary to evaluate the strength constant through direct field test.

However, in the civil design stage, it is virtually impossible to conduct a large-scale field test at a predetermined depth. Therefore, it is required to develop a method of evaluating the ground strength constant of the weathered zone layer that can evaluate the strength constant from the relatively easy-to-run full-scale field test results. There is a situation.

In order to develop a method for evaluating the ground strength constants of weathered zones, it is necessary to secure basic data by performing mechanical tests such as stress-strain characteristics according to the weathering degree of the foundation rock which is widely distributed in Korea.

The stress-strain characteristics are usually analyzed by an analytical method applying fracture criteria and co-expansion theory to the appearance of excavation and compression test of rock at the test site to a location corresponding to the weathering grade at a predetermined site. .

Here, the compression test is carried out in a three-axis compression test, a direct shear test, a uniaxial compression test, etc., which simultaneously compresses the rock in the X-Y-Z-Z direction. The preparation is performed according to the following steps.

1. Excavation of test site-2. Selection of specimen and reaction anchor-3. Ground drilling-4. Anchor installation (Growing)-5. Slime removal-6. Test block positioning-7. Test block production-8. Horizontal Positioning of Reaction Concrete Blocks-9. Excavation of Concrete Block Locations-10. Horizontal Reaction Concrete Placement-11. Test Block Finishing and Capping-12. Reaction Support Installation-13. Loading Plate and Loading Device Installation-14. Reaction Stand installation-15. Anchor reaction force connection-16. Deformation measuring device installation-17. Compression

In the compression test preparation step performed as described above, 1. Test excavation to 11. Test block finishing and capping steps are performed by digging the test ground and forming a part of the rock into a cube shape, and thus mainly dependent on manpower. 12. Reaction force support installation ~ 16. Deformation measuring device installation is a step of deploying and arranging a steel structure for supporting and arranging the compression device around the exposed rock, and a frame for supporting the hydraulic device.

In carrying out such a compression test, the installation of the device has a cumbersome and inefficient problem of designing and manufacturing a steel structure and a hydraulic system according to the site conditions every time the site to be measured changes.

The purpose of the present invention is to provide a three-axis compression tester for evaluating the ground strength constant of the weathering table layer, which can be easily folded and transported to suit the field three-axis compression test, and can be installed and completed only in the order of deployment in the field. It is to provide a simple and easy to measure the ground strength constant.

The device of the present invention for realizing the above object is the ground strength constant of the weathering zone layer which forms the ground by loading the load in the 3-axis direction of the specimen formed by excavating the ground under test and measuring the deformation characteristic in each direction. In evaluating, the pair consists of a pair of reaction force supporting rods intersected with each other, so that assembly and disassembly can be simplified, and a reinforcement plate is attached to the intersection of the reaction force supporting rods to reinforce the mechanical strength of the portion. The state becomes a composition.

A normal hydraulic jack is disposed below the reinforcement plate to load the specimen in the Z direction, and the reinforcement plate has protrusions integrally formed at four corners to firmly intersect the reaction force supporting rod. It can be attached and supported, each of the protrusions is provided with a fastening bolt for attaching the cover integrally.

Hereinafter, the present invention will be described in detail with reference to preferred embodiments according to the accompanying drawings.

 The device according to the present invention is composed of a pair of reaction force supporting rods 2 intersected as shown in FIG. 1 and a reinforcement plate 4 mounted at the intersection of these reaction force supporting rods 2.

The reaction force supporting rod 2 is formed of a steel pipe in the form of a chassis, and the intermediate portions intersecting with each other are formed by the recesses 20 reduced in thickness by half, and the end holes 22 are formed in both ends thereof. .

 The reinforcing plate 4 is assembled by fitting at the intersection of the reaction force supporting rods 2, and integrally formed with a right triangular shape projecting portion 40 for supporting both sides of the reaction force supporting rods 2 at four corners. The center of the upper surface of each of the protrusions 40 is provided with a fastening bolt 42 is provided.

The cover 44 is covered above the reinforcing plate 4. Through holes 46 corresponding to the fastening bolts 42 are bored at four corners of the cover 44, and the nut 48 may be integrally attached to the reinforcing plate 4 by screwing the nut 48.

In addition, it is preferable that the upper surface of the cover 44 has a shape having a considerable thickness so as to prevent buckling deformation of the reaction force supporting rod 2 intersected downwardly. In the present invention, the upper surface of the cover 44 is angular as shown, so that it can withstand the external force applied in the vertical direction.

In the long hole 22 of each reaction force supporting rod 2, a normal steel bar A used as a reaction force anchor is penetrated. In addition, a clip 24 is inserted into the outer circumference of the reinforcing bar A to maintain a state of being integrally connected with the reaction force supporting rod 2, and the bottom surface of the reinforcing plate 4 is a normal hydraulic jack J during use. Will be located.

The inventive device of the above-described configuration is installed and used on the ground in the order of steps according to the following description.

Estimation of weathering degree and required strength based on the results of drilling survey, indoor weathering index test, and dynamic test, select the original location suitable for the test purpose, and then excavate flat to the predetermined area to the predetermined test location and place reaction anchor on the ground Select.

Reaction anchors should be installed with design axial forces reflecting sufficient safety to anticipate rock strength, and the spacing and depth of reaction anchors should be such that the effects of manual earth pressure caused by the frictional forces of the anchorage after anchor tension and anchorage do not affect the specimens. Of course.

More specifically, as shown in FIG. 2A, the drilled ground is drilled and embedded with reinforcing bars (A) in each of the four grounds as a reaction force anchor, and then fixed by grouting construction. Is completed.

Next, as shown in FIG. 2B, a cube-shaped specimen T is formed in the center of the ground surrounded by four reaction force anchors, whereby a reaction force concrete block C is formed and arranged for each furrow formed around it. The X-axis hydraulic / load cells X1 and X2 and the Y-axis hydraulic / load cells Y1 and Y2 are disposed between the specimens T, respectively.

The X-axis hydraulic pressure / load cell (X1, X2), Y-axis hydraulic pressure / load cell (Y1, Y2) is applied to the equipment known in the prior art.

The upper surface of the specimen (T) is surface-treated with gypsum or mortar to reduce the progress of weathering as much as possible, and to finish horizontally to uniform load.

On the upper surface of the finished specimen T, a hydraulic jack J is arranged as a load carrying means, as shown in FIG. 2C, and a reaction force supporting rod 2 is interposed thereon and a reinforcing plate 4 and a cover. While being assembled to be integrally formed by the combination of the 44, the long holes 22 formed at both ends of these reaction force supporting rods 2 are penetrated and fixed by the clip 24 through the rebar A embedded with the reaction force anchor. .

As described above, the reaction force supporting rods 2 intersected with each other should be arranged so as to be substantially horizontal so as not to cause a bias of load to the specimen T during loading.

The test is performed by measuring deformation characteristics generated by loading in the uniaxial or triaxial direction of the specimen T. Such a test procedure is performed in the same manner as the conventional ground constant evaluation test of granite weathered rock. .

The compression device for evaluating the ground constants of the granite weathered rock of the present invention having the configuration as described above has a structure in which a reinforcing plate is attached to the intersection of a pair of reaction force supporting rods which are arranged to be crossed, The structural weakness is firmly compensated, so that the supporting rod can withstand the reaction force generated in the Z direction in the process of loading in three axes of the specimen without deformation.

In addition, the test in situ: 1. Excavation of the site under test-2. Selection of test specimen and reaction anchor position-3. Ground drilling-4. Anchor installation (growing)-5. Slime removal-6. Test block positioning-7 Manufacture of test blocks-8. Selection of horizontal reaction concrete blocks-9. Excavation of concrete blocks-10. Horizontal reaction concrete placement-11. Test block finishing and capping are the same as the conventional ground constant evaluation test However, in the next step, the hydraulic jack is placed on the upper surface of the specimen, and a pair of reaction force supporting rods are intersected thereon to be connected to the reinforcement plate, while the simple operation of connecting the reinforcing bars to the ends of each supporting rod. Workability is good because the installation is completed.

In particular, since the disassembly after the test is easy to carry and move, there is an advantage in eliminating the hassles and work difficulties, which had to be newly designed and placed in the field for each test position in the past.

Claims (3)

In evaluating the ground strength constant of the weathering band layer of the foundation rock which forms the ground by loading the load in the 3-axis direction of the specimen formed by excavating the ground under test, and measuring the deformation characteristics in each direction, A pair of reaction force supporting rods formed with concave portions of which intermediate portions that cross each other are reduced to about one-half thickness and having long holes through which reaction force anchors are connected at both ends thereof; A reinforcing plate which is integrally formed at four corners to support the side surfaces of the cross reaction force supporting rods, and supports the cross point of the cross reaction force supporting rods; A cover for allowing the reaction force supporting rod to be integrally coupled with the reinforcing plate by penetrating through holes formed at all four corners through the fastening bolts attached to the upper surfaces of the protrusions of the reinforcing plate and fastening and connecting with nuts. A triaxial compression test apparatus for evaluating the ground strength constant of the weathering zone layer which is comprised between the lower side of the said reinforcement board and the upper surface of the specimen, and is equipped with the normal hydraulic jack which loads the Z direction load to the specimen. The method according to claim 1, wherein the cover covered with the upper surface of the reinforcing plate is formed in the form of an angular surface so as to reinforce the strength of the intersection of the reaction force supporting rod 3 Axial compression tester. The triaxial compression test apparatus according to claim 1, wherein the reaction force anchor penetrating the reaction force supporting rod is fixedly connected by a clip.

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