KR20020017716A - Equipment for CRS Consolidation Test - Google Patents

Abstract

PURPOSE: A CRS(Constant Rate of Strain) compacting apparatus is provided to simulate circumstances precisely by compacting a sample and radially draining water from the sample in an inner wall of a housing with a radial drain part. CONSTITUTION: A CRS compact device comprises a housing(10) containing a sample and having an air hole(14); a pressurizing part(20) applying pressurized water through upper and lower parts of the housing; a gap hydraulic pressure measuring part(20a) measuring hydraulic pressure in the lower part of the sample; a loading plate(30) installed in the upper part of the sample; a loading bar(40) penetrated through the upper part of the housing to press the loading plate; and a radial drain part(50) draining water from the sample in the inner wall of the housing. The radial drain part has a porous compact ring, and an absorbing plate installed in the porous compact ring to absorb water from the sample. The sample is compacted at the constant rate of strain in testing compression of the soft ground, and the test is performed precisely with draining water radially from the sample.

Description

Radial Drainage Consolidation System {Equipment for CRS Consolidation Test}

The present invention is to conduct a consolidation test by collecting the viscous soil of the soft ground in order to improve the ground when constructing structures such as roads, bridges, buildings, etc. on the soft ground, in particular radiation that can more accurately simulate the situation of the soft ground site It relates to a constant rate of strain (CRS) consolidation apparatus capable of directional drainage.

When constructing structures in the field of civil engineering, especially in geotechnical engineering, structures are often placed on soft ground. In this case, soft ground mainly refers to cohesive soil, and if the structure is constructed directly on it, overlying or uneven settlement over the long-term allowable settlement will occur, which will adversely affect the structure and eventually cause the structure to collapse. Let's go. Therefore, in order to construct a structure on such ground, improvement of the ground must be preceded first.

In order to improve the ground, first, the compressive characteristics of clay soil are investigated through field or indoor experiments. At this time, the laboratory test is the consolidation test, which is one of the most widely conducted tests in the field of geotechnical engineering.

Conventionally widely used consolidation apparatus is a vertical direction constant rate of strain (CRS) consolidation test apparatus drained in the vertical direction.

That is, in the conventional compaction apparatus, as shown in FIG. 1, a housing 1 having a space in which viscous soil sample T can be placed therein and having an air hole 1a, and upper and lower portions of the housing A pressurizing section 2 for saturating the sample by inserting the pressurized water through the pressurized water pipe 6, and a pore water pressure gauge 2a provided to measure the state of the sample (water pressure at the lower part of the sample) to be condensed therefrom; And an absorbent plate 3 installed on an upper portion of the sample T in the inner space of the housing 1 to suck moisture from the sample, and an upper portion of the absorbent plate 3 installed in the upper portion of the absorbent plate 3. It consists of a loading plate (4) that is bored, and a loading bar (5) which penetrates the upper portion of the housing (1) and compresses the loading plate (4) and includes a load cell.

In the conventional consolidation apparatus configured as described above, the sample of the soft ground to be constructed is collected and put into the housing 1, and then pressurized water is pressed into the housing through the pressurized water pipe 6. The reason for pressurizing the pressurized water at this time is to remove air by dissolving the fine air bubbles contained in the sample T with the pressurized water. When the load is applied to the loading bar 5, the sample is compressed and moisture contained in the sample is primarily absorbed by the absorbent plate 3 and drained in the upper vertical direction through the loading plate 4 through which the holes are drilled. . When the load is applied while pressing the loading bar 5 at a constant speed, a deformation of the sample occurs at a constant speed. At this time, the stress of the upper part of the sample, the pore water pressure and the displacement of the lower part are measured and analyzed.

The conventional test of the sample as described above can shorten the test period of the sample and saturate the sample as much as possible by pressurizing the pressurized water inside the housing. Passing holes (4a) of (4) are drilled in the vertical direction up and down, the water is forced to drain in the vertical direction. When drained in the vertical direction, it is difficult to obtain accurate data because it is impossible to reproduce the site situation drained in the radial direction when the actual ground is improved.

Accordingly, an object of the present invention is to provide a CRS consolidation apparatus capable of radial drainage that can more accurately simulate the field situation by allowing the drainage to be radially close to the site situation, unlike the conventional one that is drained in the vertical direction. .

1 is a cross-sectional view of a conventional compaction apparatus drained in the vertical direction

Figure 2 is a cross-sectional view of the compaction apparatus according to the present invention

Figure 3 is a partial detailed view of Figure 2 as the present invention

Figure 4 is a state of use of the compaction apparatus according to the present invention

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

10: housing 11: bottom plate

12: side wall plate 13: upper plate

14: Air hole 15: Fastening rod

16: displacement measuring instrument 20: pressure unit

21: pressure water pipe 22: pore water pressure

30: loading plate 40: loading bar

41: load cell 50: radiation drainage

51: porous milling 51a: water hole

51b: protrusion 52: absorbent plate

53: rubber ring 54: auxiliary cylinder

60: loading frame 61: upper support

62: bottom plate 63: stand

T: Sample

Hereinafter, the technical configuration of the present invention in detail.

The radiation drainage consolidation apparatus of the present invention forms a space for putting a sample therein, a housing having an air hole, a pressurizing portion for saturating the sample by putting pressurized water through upper and lower portions of the housing, A pore water pressure measuring part provided to measure the state of the sample (water pressure at the center of the lower part of the sample), a loading plate installed on the upper part of the sample in the inner space of the housing, and a loading plate pressed through the upper part of the housing The configuration of the loading bar is not different from the conventional technical concept.

However, the present invention is to have a basic technical idea of the present invention is provided with a radiation drainage portion for draining the water contained in the sample in the radial direction on the inner peripheral wall of the lower housing housing.

Hereinafter, the present invention will be described in more detail with reference to exemplary embodiments shown in the accompanying drawings.

In the embodiment of the present invention, as shown in FIG. 2, the housing 10 having a space for the sample T therein and having an air hole 14, and the upper and lower portions of the housing Pressurizing section 20 to apply pressurized water through, pore water pressure measuring section 20a provided to measure the state of the sample (water pressure at the center of the lower part of the sample) condensed in the radial direction, and inside the housing 10 A loading plate 30 installed above the sample T in the space, a loading bar 40 for pressing the loading plate 30 through the upper portion of the housing 10, and an inner circumferential wall below the housing 10. It consists of a radiation drainage portion 50 for draining the water contained in the sample in the radial direction,

The radiation drainage part 50 is installed around the lower inner circumferential surface of the housing 10 and has a through-hole milling 51 in which the through-holes 51a are drilled in the lateral direction, and is installed on the inner circumferential surface of the porous press-milling 51 and the sample. It is to implement the basic technical idea of the present invention in that it is composed of an absorbent plate 52 which directly absorbs water contained in the water.

Looking at the components constituting the present invention in detail, the housing 10 is cylindrical to form a space therein. As shown in FIG. 2, the lower plate 11 includes a cylindrical side wall plate 12 and an upper plate 13. These three structures are separated from each other and assembled into the fastening rods 15 as in the prior art.

When the water is filled in the housing 10 through the pressurized water pipe 21 in this assembled state, the air in the housing 10 exits through the air hole 14 formed in the housing upper plate 13. The pressurizing part 20 pressurizes the pressurized water through the pressurized water pipe 21 connected to the upper part and the lower part of the housing 10, and measures the pore water pressure of the sample as the sample T is consolidated in the pore water pressure measuring part 20a. The pore pressure receiving device 22 is not significantly different from the conventional one in that it is installed.

The loading plate 30 is shown as hermetically closed in the vertical direction as a structure that presses directly on the upper portion of the sample (T), as shown in FIG. 2, but may pass through holes in the vertical direction as in the prior art. At this time, the absorbent plate for sucking moisture may be disposed in the lower portion of the loading plate as in the prior art. This has the advantage that the condensation time can be further shortened by allowing the water contained in the sample to drain not only in the radial direction but also in the vertical direction.

Loading bar 40 is a structure that transmits the load to the loading plate 30, as shown in Figure 2, through the upper center of the housing 10 is connected to the loading plate 30 functionally different from the conventional one There is no bar, but the ball bearing containing silicon grease is used to reduce the friction and it can be checked and corrected during the experiment. In addition, the load cell 41 is attached to the outside of the housing 10 (see Fig. 4).

Radiation drainage portion 50 is a key technical matter of the present invention, as shown in Figures 2 and 3, is installed around the inner circumferential surface of the lower housing 10 and the porous milling 51 through which the through holes 51a are drilled in the lateral direction. And a synthetic resin absorbent plate 52 which is provided on the inner circumferential surface of the porous compacting mill 51 and directly absorbs the moisture contained in the sample.

Here, the porous compression mill 51 has a protruding jaw 51 formed on the lower outer side, and a lower diameter of the inner circumferential surface is formed larger than the upper portion so that the absorbent plate 52 can be fitted snugly. In addition, a groove is formed between the lower end of the porous compression ring 51 and the lower plate 11 of the housing 10 to insert the rubber ring 53 to increase watertightness (see FIG. 3).

Therefore, when the sample T embedded in the absorbent plate 52 is consolidated by the loading plate 30, the moisture of the sample is drained in the radial direction in which the absorbent plate 52 is located. The water absorbed by the absorbent plate 52 is moved to the inner space of the housing through the water passage 51a of the porous milling 51.

On the other hand, the auxiliary cylinder 54 in close contact with the inner peripheral surface of the housing 10 can be additionally installed. The auxiliary cylinder 54 serves to increase the watertightness while supporting it by pressing the porous compact ring 51. At this time, the lower end of the auxiliary cylinder 54 is placed on the protruding jaw 51 formed to the outside of the lower end of the porous pressing ring 51 and formed a minute gap with the porous pressing mill 51 and drained through the water holes 51a. Allow water to escape into the interior of the housing.

On the other hand, although not shown in the drawings as another way to drain the water drained through the through holes 51a into the interior space of the housing 10, the channel grooves at equal intervals in the vertical direction on the outer peripheral surface of the porous milling 51 Alternatively, as another method, the channel grooves may be formed at equal intervals in the vertical direction on the inner circumferential surface of the auxiliary cylinder 54. By forming the channel grooves in the vertical direction on the outer circumferential surface of the porous compression mill 51 or the inner circumferential surface of the auxiliary cylinder 54, the water of the sample passes through the channel grooves into the upper housing internal space while passing through the water passage grooves. (54) It has the advantage that the liver can be held in close contact with each other firmly.

4 shows a state of use of the compaction apparatus of the present invention. That is, the consolidation apparatus is installed in the loading frame 60. When the loading bar 40 is supported on the lower surface of the upper support 61 of the loading frame 60 and the pedestal 63 installed on the lower plate 62 of the loading frame is lifted by a motor, the loading plate 30 is loaded through the loading bar 40. The sample T is consolidated. This is not much different from the conventional one.

Such a condensation apparatus capable of radial drainage of the present invention has a radial drainage portion 50 in the inner space of the housing 10 to drain the moisture of the sample in the radial direction to more accurately simulate the field situation. Has

Claims (5)

A housing 10 having an air hole 14 formed therein, and a pressurizing portion 20 for pressurizing pressurized water through an upper portion of the housing, and a lower central portion. The pore water pressure measurement unit 20a provided to measure the state of the sample to be consolidated, the loading plate 30 installed above the sample T in the inner space of the housing 10, and the housing 10. In the configuration of the loading bar 40 for pressing the loading plate 30 through the upper portion, CRS consolidation apparatus capable of radial drainage, characterized in that it comprises a radial drainage portion 50 for draining the water contained in the sample in the radial direction on the lower inner peripheral wall of the housing 10 in which the sample (T) is built . The method of claim 1, wherein the radiation drainage portion 50 is installed around the inner peripheral surface of the lower portion of the housing 10, the porous compacting mill 51 through which the through holes 51a are drilled in the lateral direction, and the porous compacting mill 51 CRS consolidation apparatus capable of radial drainage, characterized in that the absorbent plate 52 is installed on the inner circumferential surface of the) and directly absorbs the moisture contained in the sample. 3. The CRS compaction apparatus as claimed in claim 2, wherein a groove is formed between the lower end of the porous compacting ring (51) and the lower plate (11) of the housing to insert a rubber ring (53). According to claim 2, wherein the auxiliary cylinder 54 in close contact with the inner circumferential surface of the housing 10 is additionally installed, the lower end of which is mounted on the protruding jaw 51 formed outside the lower end of the porous compression mill 51 CRS compaction apparatus capable of radial drainage, characterized in that to form a fine gap with the porous compacting (51). 3. The CRS consolidation apparatus as claimed in claim 2, wherein the porous consolidation ring (51) has channel grooves formed on the outer circumferential wall in up and down directions.