JPS63297621A - Tester for both penetration and vane - Google Patents

Abstract

PURPOSE:To easily carry out penetration test and vane test by the same tester by attaching a number of vanes to the periphery of a resistor for penetration testings. CONSTITUTION:A connector 2 connected to a penetration rod 1, a split barrel 3 of a two-split pipe connected to the connector 2, and a slender shoe 6 forming a resistor for penetration testing on the lower end of the barrel 3 are provided. A cutting edge 7 is attached to the lower end of the shoe 6, and a number of vanes 5 are attached longitudinally in the periphery of the shoe 6. Penetration testing and vane testing can thus be very easily performed by the same tester.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an apparatus for obtaining information on the ground excluding bedrock etc., and particularly relates to a penetrating test and a vane test capable of performing both a GS person test and a vane test. Regarding combined use equipment.

Conventional technology Among ground investigations in Japan, the eff semi-penetration test has been standardized in JIS for a long time, and is used far more often than other investigation testing methods. This test is originally suitable for coarse-grained ground such as sand and sandy soil, and this test method indicates the strength of the ground by the number of blows required to penetrate 30C11 into the ground, and is very rough. However, because the test method is very simple, it is currently widely used for cohesive soils. On the other hand, the vane test is an in-situ test method suitable for soft and cohesive soil, which determines the strength of the soil from the torque when rotating the vane, and the standard penetration test is the best method for determining the strength of cohesive soil. Much more accurate. However, it is almost no longer used for reasons such as the complexity of the exam.

In addition, improvement works such as compacting the ground, especially sandy ground, are often carried out, and standard penetration tests are also generally used to judge the degree of improvement.

However, because the stress state of natural ground and the underground do not necessarily match, penetration tests are often used because they are simple and easy to investigate, even if they are insufficient for investigation.

Various research and developments have been conducted on vane tests since ancient times, but most of them have been aimed at improving accuracy, and are aimed at solving problems such as turbulence caused by penetrating the vane into the ground, rotational speed, and excessive pore water pressure. [What is it? - On the other hand, penetration tests include research and development of large-scale one-person tests for gravel soil, impact energy, and correlation with other detailed survey test results.

In addition, static penetration tests are also standardized in JIS, and various other tests are being researched and developed. Recently, research and development efforts have been focused on obtaining highly accurate and detailed ground information for both vane tests and penetration tests.

Problems to be Solved by the Invention As described above, the standard penetration test according to the prior art can only obtain a very rough value, and the Vane test has drawbacks such as its complicated method.

Technical means for solving the problem In the present invention, a plurality of vanes for determining the shear strength of the ground are mounted around a long and thin resistor for an 11-person test, thereby making it possible to solve the problem by installing a plurality of vanes to determine the shear strength of the ground. The test can be performed using almost the same method, and the penetration resistance values such as the number of blows (N value) are equivalent to those obtained in the original test. The problem is solved by a device in which vanes are attached to the resistor, for which approximate values can be easily obtained and can be applied to various ground types.

Embodiment As shown in FIGS. 1 and 2, the combined penetration test and vane test device according to the present invention includes a connector 2 connected to a noble rod 1, and a split barrel 3 of a bisected vibrator connected to the connector 2. and an elongated shoe 6 that forms a resistor for noble testing and is screwed to the lower end of the shoe. As shown in the figure, a stepped cutting edge 7 is formed at the end of the shoe 6, and a plurality of vanes 5 are mounted in the longitudinal direction on the outer periphery of the shoe 6 for determining the shear strength of the ground.

In addition, in the drawing, the reference numeral 4 does not indicate an earth removal hole.

In the above device, the shoe 6 can be penetrated into the ground by applying an impact to the penetration rod 1 to perform a one-person test, and at the same time, the shoe 6 can be rotated by rotating the insertion rod. A vane test can be performed using In this way, the shear strength of the ground can be determined from the side bottom resistance of the t'1 human resistance body 6, but in order to more accurately determine the resistance of the tip section, the uneven cutting edge 7, that is, two types of taper angles are used, and the shear strength is alternately set. By setting the cutting edge angle at different angles, it is possible to measure the resistance at the tip.

In addition, to reduce frictional resistance in areas other than the vane,
The outer diameter of the split barrel 3 is smaller than the outer diameter of the shoe 6.

A soil sample will be placed inside the split barrel for the penetration test, so if you pull it out, you will get a disturbed sample. If the jetting is carried out after the penetration test and the vane test sample, the earth and sand can be discharged from the four discharge holes and the N[I and shear force can be continuously determined.

As described above, in the combined penetration test and vane test device according to the present invention, the penetration test specifications are exactly the same as the standard penetration test,
The shapes and dimensions are determined through experiments so that almost the same N value can be obtained. During the penetration test, the sampler, which usually has low antibodies, is pulled up, but in order to reduce the resistance at this time, the rod is rotated several times before being pulled out.

Instead of using a motion to reduce this resistance, this method determines the shear strength of the ground by measuring the maximum torque when rotating with a torque wrench, etc., and is not much different from the conventional standard penetration test. It is characterized by Furthermore, actual m
An example is the standard penetration test 7. Although it is based on L number of test pieces, it is also possible to use a large-scale penetration test or a static cone f one-person test as the basis.

Next, with reference to FIGS. 3 and 4, the results of an experiment using a device for a combination of a one-person test and a Vane test according to the present invention will be explained.

FIG. 3 is a diagram comparing the number of hits by the conventional standard penetration test and the number of hits by the device of the present invention, where the horizontal axis is the N value by the standard penetration test, and the vertical axis is the number of hits shown in Figure 1. ,
It will be seen that the N value obtained by the apparatus of the present invention shown in FIG. 2 is in very good agreement with -C.

Figure 4 is a diagram comparing the shear strength obtained from the indoor triaxial test results using the vane test bundle using this device and the undisturbed collected sample, and shows the shear strength obtained from the vane test using the device of the present invention. The vertical axis shows the shear strength obtained by taking an undisturbed sample in the immediate vicinity and conducting a two-wheel compression test indoors, and the horizontal axis shows the shear strength.

In addition, in my country, N5pt indicates the standard n-person test result, N N-Vane indicates the 4-person resistance value of this device, and τC
U indicates the U shear strength determined by the indoor triaxial test, and τN-vane indicates the shear strength determined by the present Vtv11.

As can be seen from the figure, there is a good correlation between the two, and the results obtained using the detailed ground investigation test f method, which is normally conducted, match the results of the extremely simple investigation test using the device of the present invention. You will understand.

Effects of the Invention According to the combined penetration test and vane test device according to the present invention, the penetration test and the vane test can be performed extremely easily with the same device.

[Brief explanation of drawings]

Figure 1 shows a combined penetration test and vane test device U according to the present invention.
2 is a bottom view of the shoe shown in FIG.
Figure 3 shows the results of the penetration test between the device according to the present invention and the prior art, and Figure 4 shows the shear strength determined using the device according to the present invention and the prior art test device. FIG. 1... Penetration rod, 2... Connector head, 3... Split barrel, 4... Earth removal hole, 5... Vane, 6... Shoe, 7... Uneven cutting edge.

Claims (1)

[Claims] A device for combined penetration testing and vane testing, comprising a long and slender rotatable resistor for penetration testing, and a plurality of vanes mounted around the resistor in its longitudinal direction to determine the shear strength of the ground. .