JPH0637748U - Measuring device for soil density and water content - Google Patents

Abstract

(57) [Summary] [Purpose] To measure soil density and water content in a short time, with high accuracy, and by simple work. A radiation source unit 6 in which radiation sources 4 and 5 made of radioisotopes are housed and mounted so that it can be inserted into the ground;
A detector 9 in which the detectors 7 and 8 are housed at the same depth as the detector 5 and which can be inserted into the ground, and calculators 2 and 3 for calculating soil density and water content based on signals from the detector 9 are provided. Prepare

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a soil density / water content measuring device applied to the field of civil engineering and construction, particularly when managing an embankment near the surface of a fill dam.

[0002]

[Prior art]

 Conventionally, when measuring the density and water content of soil, as shown in Fig. 3, the soil in a range wider than the measurement range is dug down to smooth out the surface irregularities, and the diameter is 20 cm or 30 cm, and the depth is 30 cm. A sampling method is known in which 20 cm or 30 cm of soil is directly sampled in a sample container and measured by a measuring device. In addition, as shown in Fig. 4, a radiation source consisting of a radioisotope that emits gamma rays and neutron rays is inserted into the ground, and the gamma rays and neutron rays emitted from the two radiation sources are placed on the ground. Radiation measurement (RI) methods, which measure with a dispenser and a moisture detector, are known. In this RI method, the amount of gamma rays passing through the soil can be measured with a detector, and the density can be determined from the amount. Similarly, the amount of neutron rays can be detected with a detector. By doing so, the water content of the soil can be calculated.

[0003]

[Problems to be solved by the device]

 However, of the above-mentioned conventional methods, the sampling method of FIG. 3 is time-consuming and requires time to obtain a measured value, the measurement accuracy is poor, and it is difficult to collect deep points. I have a problem. In addition, the radiation measurement (RI) method of FIG. 4 has a problem that the radiation path is unstable and all radiation rays are picked up by a detector such as a GM tube, so that the measurement accuracy is poor. As it is affected by the unevenness of the ground surface, it has not been the alternative to the sampling method.

The present invention solves the above problems, and an object of the present invention is to provide a measuring device capable of measuring soil density and water content in a short time, with high accuracy, and by a simple operation. To do.

[0005]

[Means for Solving the Problems]

 Therefore, the soil density / moisture content measuring apparatus of the present invention contains the radiation sources 4 and 5 made of radioisotopes, and the radiation source unit 6 which is installed so as to be inserted into the ground, and the radiation source 4 and A detector 9 in which the detectors 7 and 8 are housed at the same depth as 5 and is inserted so that it can be inserted into the ground, and calculators 2 and 3 for calculating soil density and water content based on signals from the detector 9 are provided. It is characterized by being equipped. It should be noted that the numbers added to the above configurations are for comparison with the drawings for easy understanding of the present invention, and the configurations of the present invention are not limited thereby.

[0006]

[Action]

 In the present invention, the radiation from the radiation source travels in a straight line at a certain depth and is detected by the detection unit, so that the path is stable and only the gamma rays and neutron rays of specific energy that have passed through the ground can be detected. The measurement accuracy can be improved without being affected by the unevenness of the ground surface.

[0007]

【Example】

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the soil density / water content measuring device of the present invention.

The measuring device 1 includes a moisture measuring calculator 2 and a density measuring calculator 3 inside, and a radiation source 4 or 5 made of a radioisotope is housed at one end of the measuring device. The radiation source section 6 is provided so that it can be inserted into the ground. On the other side of the measuring device 1, there is provided a detection section 9 in which detectors 7 and 8 are housed at the tip and which is installed so as to be inserted into the ground. The detectors 7 and 8 are arranged so as to face the radiation sources 4 and 5 at the same depth, and are connected to the water content measuring calculator 2 and the density measuring calculator 3, respectively.

In the present invention, two holes are formed in the ground, and the radiation source section 6 and the detection section 9 are inserted into the ground. Among the radioactive isotopes, Co-60 (Cobalt 60) that emits gamma rays and Cf-252 (Caliphonium 252) that emits neutron rays are set in the radiation source section 6. At this time, in order to insert the detectors 7 and 8 into the ground, it is necessary to make the detectors as small as possible. Therefore, for gamma rays, instead of the conventional GM tube, for example, NaI (inorganic scintillator) or For example, NE ₂₁₃ (liquid scintillator) or Li glass (solid scintillator) is used to further reduce the size by using germanium, and for example, a neutron tube is used for detecting the neutral beam. If Cf-252 is used as the radiation source and NE ₂₁₃ is used as the detector, both density and moisture can be detected with one radiation source.

In the measuring device of the present invention having the above-mentioned configuration, the radiation from the radiation sources 4 and 5 travels at a constant depth in a straight line and the amounts of gamma rays and neutron rays of specific energy are detected by the detectors 7 and 8. Therefore, the measurement accuracy can be improved. In addition, the measurement accuracy can be improved without being affected by the unevenness of the ground surface.

FIG. 2 shows an application example of the present invention, in which the measuring device 1 is mounted on the measuring vehicle 10 and the measurement result calculated by the calculator 11 can be transmitted to the central office via the antenna 12. By doing this, unlike conventional sampling methods, mechanization and automation are possible.

[0012]

[Effect of device]

 As is apparent from the above description, according to the present invention, the radiation source part, which stores the radiation source made of radioisotope and is mounted so that it can be inserted into the ground, and the detector are stored at the same depth as the radiation source. Since it is equipped with a detector that can be inserted into the ground and a calculator that calculates soil density and water content based on the signals from the detector, it is a quick, highly accurate, and simple operation. The soil density and water content can be measured with. Moreover, since it is not affected by the unevenness of the ground surface, it is not necessary to smooth the unevenness.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing one embodiment of a soil density / water content measuring device of the present invention.

FIG. 2 is a configuration diagram showing an application example of the present invention.

FIG. 3 is a diagram for explaining a conventional sampling method.

FIG. 4 is a diagram for explaining a conventional RI method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Measuring device, 2 ... 3 Arithmetic unit, 4, 5 ... Radiation source, 6 ... Radiation source part 7, 8 ... Detector, 9 ... Detection part

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Shinichi Nishimura, 1-3-2 Shibaura, Minato-ku, Tokyo Shimizu Construction Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A radiation source comprising a radioisotope is housed,
A radiation source unit that is insertable into the ground, a detection unit in which a detector is housed at the same depth as the radiation source and that can be inserted into the ground, and a density of soil due to a signal from the detection unit, Soil density characterized by having a calculator for calculating the amount of water
Water content measuring device.