JPS5871432A - Soil test method - Google Patents

Abstract

PURPOSE:To conduct a soil test which is equal to a triple spindle test with simple operation by pressurizing a cylindrical specimen of hollow cylindrical pressure chamber with rubber bushing inside by the both ends thereof with lateral pressure. CONSTITUTION:When a cylindrical specimen 3 is inserted into an inside chamber formed with a thin rubber cylinder 4 and hydraulic pressure of a pressure chamber 1 is controlled, desirable side pressure is put upon the specimen 3. Under this condition, the ends pressure is put upon the specimen 3 by means of loading piston 10 and porous discs 5 and 6 and deformation valumen of the specimen 3 is measured according to movement volume, etc. of the piston 10 until the deformation becomes discontinuous so as to form Mohr's circle by stress. Adhesive power and internal friction angle of the soil specimen can be determined by a test which is equal to a triple spindle test with simple operation by drawing a tangent to Mohr's circle which corresponds to different side pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a soil testing method using a uniaxial testing machine for the purpose of conducting a test similar to that of a triaxial testing machine.

Conventionally, soil tests can be conducted using either a uniaxial tester or a triaxial tester, but when using a -axial test, pressure is applied in the axial direction to a VC-shaped cylindrical specimen. This method measures the applied pressure and volume change, but since the pressure is applied only from the -axial direction, good results can be obtained when the specimen is made of clay, and the influence of progressive fracture is small ( , the shear plane does not occur at a fixed position, but at the weakest position, making it possible to conduct a quick test that can meet the demands of the field. However, if the specimen is not made of clay, There was a risk that it would collapse in the second half of the rolling process, resulting in results that did not match the actual situation.On the other hand, the triaxial testing machine measures changes in applied pressure, volume changes, and pore water pressure while reducing lateral pressure and pore pressure. Although it has the property of being able to obtain data that corresponds to the actual situation even in soils that are easily disintegrated, the overall equipment is complex because the specimen and equipment are installed underwater, making it difficult to conduct tests easily and in a short time. Since it is difficult and expensive to perform, it is inappropriate as a test that can be applied immediately in the field.

However, in this invention, a specimen coated with thin rubber is inserted into the inside of a cylindrical pressurizing chamber, and the pressure inside the pressurizing chamber is increased to apply uniform lateral pressure to the entire circumferential wall of the specimen. By applying pressure in the direction of the end face of the specimen and measuring the applied force and volume change of the specimen, they were able to successfully obtain data comparable to triaxial testing with simple operations.

The above test can be carried out not only in air but also in water.

That is, the present invention will be explained as follows based on the apparatus shown in the accompanying drawings. In Figure 1, the cylindrical pressurizing chamber l
While filling the inside with water, one end of the communication pipe is connected to the - side, and the other end is connected to a pressurizing device (not shown).

The inner circumferential wall of the pressurizing chamber 1 deforms in response to changes in internal pressure, and applies equal pressure to the side wall of the specimen 3 inserted inside.

The specimen 3 was formed into a cylindrical shape with a fixed size for the soil to be tested, and a thin rubber cylinder t was layered on the outside thereof. As mentioned above, insert the rubber cylinder 4'' into the pressurized chamber l.
The adhered specimen J is inserted, the upper and lower end surfaces of the specimen 3 are interposed with porous disks S and 4, the base 7 and the intervening material g are brought into contact with each other, and a predetermined water pressure is applied. While pressurizing the side wall of the specimen (by reading the side pressure using the pressure gauge 9 and maintaining a constant pressure), a vertical pressure is applied to the loading piston 1oVc in contact with the surface of the intervening material.In the above, the pressing force of the loading piston 10 is Measured by a dial gauge (not shown) mounted above. In the device, the loading piston ioy arrow l/
When pressurized like this, it will drop as the pressure increases, so if you read the amount of descent and the change in pressure, and replace the amount of descent with the change in volume of the specimen, it will be the corresponding change in volume and pressure. Be able to do that.

In this way, by changing the lateral pressure and drawing a Mohr's circle as shown in Figure 3 from the corresponding total stress, and drawing a common tangent for each day, we can find the adhesive force C and the internal friction angle y. be able to. Next, the apparatus shown in FIG. 2 is obtained by installing the apparatus shown in FIG. 1 into an aquarium. In this case, since the test can be carried out with the specimen hydrated, the adhesive force and internal friction angle can be determined under conditions close to the natural state of the soil to be tested. According to the above measurement method, the influence of progressive fracture is small, the amount of volume change can be easily measured, two stress states can always be seen, and even sandy materials that are easily disintegrated can be tested, similar to triaxial testing. In addition, since there is no need to submerge the specimen in sealed water, it is extremely easy to set up and remove the specimen, and the test can be performed easily and quickly.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the device used to carry out the present invention. Figure 2 is a cross-sectional view of another device. Pressure chamber 3...Specimen da...Rubber cylinder
S, 6... Porous disc 10... Loading piston Figure 1 Procedural amendment (Own ship January 1920/1950 ψF Patent Office Director Otoshima 1) Haruki Tono 1, Incident indication Showa I6 patent application 1st 0JIIσ No. 4, Deputy
Person (Postal code: 160) Address: 29 Shinanomachi, Shinjuku-ku, Tokyo Tokumei Building, 1983
Date -) Drawing Z Contents of amendment 1 (1) No amendments are required for the QQm document, except for those listed in the appendix 0 types and 0 corrections. (J) Figures 7 and 2 of the drawings are corrected as shown in the attached sheet. and List of attached documents (1) 1 copy of the amended statement (
-) Corrected drawings / FJA specifications / Title of invention Soil testing method Scope of claims 1 A cylindrical specimen with predetermined dimensions is inserted into a hollow cylindrical pressurized chamber with a thin rubber cylinder inside, and the above-mentioned Apply the specified lateral pressure to the specimen! Pressure is applied from the end face direction in a single digit state,
The volume change due to the increase in the applied pressure is continued until the change becomes discontinuous, and then the volume change is measured in the same manner as above, using a specimen of the same quality and changing only the lateral pressure, and each of the above measurements A soil test method characterized by crossing Mohr's circle based on the value and drawing a common tangent each time to determine the adhesive force and internal friction angle. Claim 1g1 characterized in that it is installed inside or underwater.
Soil testing method J described in Claim 1, characterized in that the lateral pressure is applied by water pressure. Detailed description of the invention. It opens up and opens up. Conventionally, there are cases in which a uniaxial testing machine is used for soil testing, and cases in which a triaxial testing machine is used. - In the case of an axial test, pressure is applied to a cylindrical specimen in the axial direction and the applied force and volume change are measured. In the case of high-quality chains, the influence of progressive fracture is small, and the shear plane is not limited to a fixed position, but occurs at the weakest point, making it possible to perform rapid tests suitable for on-site chain manufacturing. However, if the specimen was not made of clay, it would disintegrate early after processing 1 and there was a risk that the measurement would be interrupted. On the other hand, a triaxial testing machine changes the lateral pressure and measures changes in applied pressure, volume changes, and pore water pressure, so it has the characteristic of being able to obtain data that corresponds to the actual situation even if the soil is easily disintegrated. However, since the specimen and equipment are installed underwater, the overall equipment is complicated, making it difficult to test easily and in a short period of time, and is expensive, making it unsuitable for tests that need to be applied immediately in the field. However, this invention uses thin rubber as the inner peripheral wall of a hollow cylindrical pressurizing chamber and inserts the specimen into the chamber to increase the pressure inside the pressurizing chamber and create an even lateral pressure around the entire circumference of the specimen. In this state, the specimen is pressurized from the direction of the end face, and the applied force and volume change of the specimen are measured, so data comparable to the three-wheel test can be obtained with simple operations. The above test can be carried out not only in air but also in water. That is, the present invention will be explained as follows based on the apparatus shown in the accompanying drawings. In FIG. 1, when water is filled into the cylindrical pressurizing chamber l, one end of the communicating pipe is connected to the negative side of the chamber, and the other end is connected to a pressurizing device (not shown). The thin rubber on the inner periphery of the pressurizing chamber deforms in response to changes in internal pressure, and applies equal pressure to the specimen jffl inserted inside the hollow cylinder. The specimen 3 is a soil sample to be tested formed into a cylindrical shape with predetermined dimensions. As mentioned above, a porous disk 6 is inserted on the pressurizing end surface to apply a predetermined water pressure to the side wall of the specimen (the lateral pressure is measured using a pressure gauge t). Read and maintain constant pressure ), the porous disk! A direct pressure is applied to the image by the loading piston IO in contact with. In the above, the pressing force of the loading piston IO is determined by [-1] by a dial gauge (not shown) installed above it. In the above device, when the loading piston IO is pressurized as indicated by the arrow 1/, it will descend as the pressure increases, so read the amount of descent and the change in the pressure, and replace the amount of descent with the volume change of the specimen. If so, the volume change and the pressurizing force can correspond to each other. 5 A rubber cylinder with a peripheral wall, t is a fixing band of the rubber cylinder. In this way, by changing the lateral pressure, drawing a Mohr's circle as shown in Figure 3 from the corresponding total stress, and drawing a common tangent for each time, the adhesive force C and the internal friction angle DA can be found. be able to. Next, the apparatus shown in Fig. 1 is the apparatus shown in Fig. 7 installed in an aquarium. In this case, since the test can be performed with the specimen hydrated, it is possible to determine the adhesive force and internal friction angle under conditions close to the natural state of the soil sample to be tested. According to the above measurement method, the influence of progressive fracture is small, the amount of volume change can be easily measured, the two stress states can always be known, and even sandy type, which is easy to disintegrate, can be tested. The same effect can be expected, and since there is no need to submerge the specimen in sealed water, it is extremely easy to set up and remove the specimen, and it has various advantages such as being able to carry out tests quickly and with a notebook. 4. Brief description of the drawings Figure 1 is a cross-sectional view of the device used to carry out the present invention, Figure 2 is a cross-sectional view of another device used, and Figure 3 is a cross-sectional view of another device used to carry out the present invention. This is the diagram you are looking for. /... Pressurized chamber 3... Specimen Tei... Rubber circle @S,
+...Porous disc 10...Loading piston Fig. 1

Claims (1)

[Claims] l A thin rubber cylinder is layered on the outside of a cylindrical specimen with predetermined dimensions, the specimen is inserted into the inside of a cylindrical pressurizing chamber, and a predetermined lateral pressure is applied to the specimen. In the applied state, pressure is applied from the direction of the end face, and the volume change due to the increase in the applied pressure is continued until the change becomes discontinuous. Then, using a specimen of the same quality, fi+! The volume change was measured in the same manner as described above by changing only the I pressure, a Mohr's circle was drawn based on each of the measured values, and a common tangent line was drawn in the valley to determine the viscous force and internal friction angle. Soil test method 3: Soil test method 3 according to claim 1, characterized in that the cylindrical specimen and the cylindrical pressurized chamber are installed in air or water; lateral pressure is applied by water pressure. A soil testing method according to claim 1, which is