JPS63138241A - Method for measuring clamping degree of bulk substance by electromagnetic wave - Google Patents

Abstract

PURPOSE:To satisfactorily recognize the state of clamping of soil by projecting the electromagnetic wave of a prescribed frequency into a bulk substance clamping the soil, receiving a reflected wave, and analyzing an electric characteristic. CONSTITUTION:The electromagnetic wave W of a frequency which is influenced most intensively by the clamping of the soil 2 is transmitted from a transmitter 5, and the electromagnetic wave W reflected from the boundary of a substrate 1 and the soil 2 is received by a receiving antenna 4 and sent to a receiver 6. The signal of this received electromagnetic wave W is sent to an analyzer 7, in which electric characteristics (for instance, the velocity of propagation, dielectric constant, attenuation factor, etc.) of the soil 2 by the electromagnetic wave W is calculated. These electric characteristics are varied by the clamping degree of the soil 2, therefore, by reading such electric characteristics, the clamping degree of the soil 2 can be known. In such a way, the measured and analyzed electric characteristics can be displayed by a graph, etc., by an indicator 8.

Description

[Detailed description of the invention] 1. Industrial application field 1. The present invention measures the degree of compaction of loose materials such as embankment materials, roadbed materials, roadbed materials, asphalt paving materials, and crushed stone materials using electromagnetic waves. It is about the method.

[Prior Art and Its Problems] Generally, compaction is carried out to reduce voids in embankments, prevent harmful subsidence, increase the bearing capacity of embankments, and stabilize the sloping surface.

Conventionally, to compact embankments, each layer is spread in a thin, uniform layer and compacted a predetermined number of times to achieve the required degree of compaction. I'm trying to get it.

By the way, the degree of compaction cannot be determined just by looking at it with the naked eye, so strict control must be exercised during construction, and it must be checked whether the required degree of compaction has been achieved.

Conventional compaction V. The experiments include the sand displacement method, the Rt (radio-7 isotobe) method, and the C Il R (californi
A bearing ratio method etc. are mainly adopted.

The sand replacement method is a method in which the volume of a hole drilled in the ground is replaced with sand, and the volume of the soil is indirectly measured to measure the density of the ground. However, this method has problems such as the long measurement time, the need to measure a large number of measurement points, and the fact that the finished ground surface is destroyed.

The RI method is a measurement method that utilizes the principle that the rate at which gamma rays are absorbed into soil particles when they pass through the soil has a constant relationship with the density of the soil. however,
Radiation such as gamma rays has problems such as radiation damage,
Not only is it difficult to bury the LFF of radiation, but there are also problems such as the need to penetrate the soil with a steel rod that emits radiation and the time required to measure it.

Furthermore, in the above CBR method, the penetration rod with a diameter of 5 cm is
The load when penetrating 5 cm is 1 + 370 kg''C
It is a method to measure the degree of compaction of soil, expressed as a percentage. However, this method not only requires extensive preparation, but also has problems in that it is easily influenced by the strength of the surface.

In any of the above methods, the measurement is discontinuous, so it is not only impossible to accurately determine whether the entire Mfi<L is satisfied, but also it is impossible to measure a large number of points in real time.

Therefore, there were problems such as not being able to expect uniform and uniform workmanship and consistent compaction construction management.

1 Objective of the Invention 1 The present invention was made to solve the above-mentioned conventional problems, and its 1-1 objective is that it is non-destructive, can measure the same point repeatedly, and takes a very short measuring time. To provide a method for measuring the degree of compaction of loose materials using electromagnetic waves, which enables short and real-time measurements, enables measurement at a large number of locations, and enables the construction of high-quality, uniformly compacted earth structures. It is in.

[Structure 1 of the Invention] The method of measuring the degree of compaction of loose material using electromagnetic waves of the present invention is to transmit electromagnetic waves of a predetermined frequency into loose material that has been spread and compacted on a base, and to compact the loose material. It is characterized by measuring changes in electrical characteristics due to
In addition, electromagnetic waves are emitted from the top surface of the compacted bulk material, reflected at the interface with the base, and the reflected electromagnetic waves are received to measure changes in electrical properties due to compaction of the bulk material.♂I11 It is characterized by:

The above-mentioned foundation must be a layer such as lower embankment, concrete layer, asphalt JI11, etc., and must have a clear boundary surface with the compacted layer above it and a surface that can reflect electromagnetic waves. .

In addition, the above-mentioned bulk materials include embankment materials, roadbed materials, roadbed materials, 7s and 7alto paving materials, crushed stone materials, and the like.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In the figure, reference numeral 1 denotes a base, on which soil 2 as a compacting material is leveled and compacted by rolling with rollers or the like.

On the surface of t2, a transmitting antenna 3 and a receiving antenna 4 are installed at predetermined intervals.

The transmitting antenna 3 emits electromagnetic waves W generated by the transmitter 5 into the soil 2.

The electromagnetic wave W emitted from L delivery Ipo 7 antenna 3 is earth 2
The light passes through the interior diagonally downward, is reflected at the boundary between the base 1 and the soil 2, travels diagonally upward, and is received by the receiving antenna 4. The electromagnetic waves W that are emitted from the transmitting antenna 3 and transmitted through the soil 2 before being received by the receiving antenna 4 may have their propagation speed reduced or energy lost due to particles, moisture, and voids in the soil 2 along the way. It becomes desolate.

The reflected electromagnetic wave W received by the receiving antenna 4 is sent to the receiver 6.

The transmitter 5 and receiver 6 are connected to an analyzer 7 and a display 8 in sequence.

Next, the operation of the apparatus of the above embodiment will be explained.

First, an electromagnetic wave W having a frequency that is most strongly affected by the compaction of the soil 2 is transmitted from the transmitter 'n5, and the electromagnetic wave W reflected from the boundary between the base fil and the soil 2 is received by the receiving antenna (
tf and sends it to the receiver 6.

The signal of the received electromagnetic wave W is sent to the analyzer 7, where the electrical characteristics of the soil 2 due to the electromagnetic wave W (eg, propagation velocity ν, relative permittivity ε, attenuation rate, etc.) are calculated. These electrical characteristics (propagation velocity ν, relative permittivity C1, lachrylation rate 'fP) are:
Since it changes depending on the degree of compaction of the soil 2, the degree of compaction of the soil 2 can be known by reading such electrical characteristics.

The electrical characteristics measured and analyzed as described above are displayed on the display 8.
Graphs and the like are processed and displayed in an easy-to-understand manner so that they can be immediately checked visually.

The state of compaction can be checked in real time as described above, so as the compaction work progresses, the compaction can be confirmed when the measured electrical characteristics reach a certain value (preset control standard). Make sure to finish the hardening work.

1 Effect of the invention 1 (1) The method of the present invention is safe in non-destructively measuring compacted bulk materials, and the measurement time is extremely short, making it possible to measure at a large number of locations and achieving high quality. Construction of an earth structure that has been uniformly compacted will take 11 hours.

(2) Since measurements can be taken continuously in parallel with compaction work, areas where compaction is insufficient can be immediately pointed out and re-compaction can be carried out.

(3) Since the measurement is non-contact and the device is lightweight,
It is also possible to install it on a device such as a computer, etc., thereby making it possible to automate the measurement.

[Brief explanation of the drawing]

The figure is a conceptual diagram of an apparatus for carrying out the measurement method of the present invention. 1...Base, 2...Top, 3...Transmission antenna, 4
... 1 receiver antenna, 5 ... transmitter, 6 ... receiver, 7 ... analyzer, 8 ... display, W ... electromagnetic wave.

Claims (2)

[Claims] (1) Electromagnetic waves of a predetermined frequency are transmitted through loose material that has been spread and compacted on a substrate, and changes in electrical properties due to the compaction of the loose material are measured. How to measure the degree of compaction. (2) Emit electromagnetic waves from above the compacted loose material, reflect it at the interface with the base, receive the reflected electromagnetic waves, and measure changes in electrical properties due to compaction of the loose material. A method for measuring the degree of compaction of bulk materials using electromagnetic waves according to claim 1.