JPH01285843A - System for measuring underground seepage water - Google Patents

Abstract

PURPOSE:To quantitatively measure the specific physical properties of the medium at a desired depth part, by respectively embedding a pair of electromagnetic wave transmitting and receiving units in the medium to be measured at a desired depth. CONSTITUTION:The time required when the electromagnetic pulse emitted from a transmission antenna AT propagates over a distance (P) to reach a receiving antenna AR is measured to calculate the effect of a attenuation due to seepage moisture exerting on the propagation speed (v) inherent to the soil quality of an objective region. In this case, as the external factor exerting effect on the propagation speed (v) of an electromagnetic wave, the delay of a time due to a rise in the content of seepage water by rainfall is calculated. That is, the change of a lowering in the propagation speed (v) is calculated and, on the basis of the comparison data with a preliminarily calculated inherent propagation speed, seepage quantity can be calculated quantitatively.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is a system for measuring underground water seepage, etc. 6. [Conventional technology] Radars that use radio waves to detect, for example, gas vibrators buried underground, or to explore the presence of underground water and strata structures, have recently been put into practical use. For example, an overview is introduced in Reference F 1), and an actual product example 2) is also published.

1) Literature “Measurement and Control” magazine Vol. 1.20. No, 8. Published by the Society of Instrument and Control Engineers.

P, 762-771 2) Product example [Underground Exploration Rator KSD-8 type].

■Kowara, a new product manufactured by Koden, emits radio waves that propagate through space from the earth's surface to attenuating media such as underground, underwater, and living organisms.
Based on the principle of detecting the shape, position, etc. of a target by the echo radio waves reflected from an object (target) existing therein, underground installation of gas 7/water pipes, electric wires, etc. It was applied to the detection of objects, geological surveys of bedrock/groundwater, etc.

[Invention or problem to be solved]

However, this type of conventional equipment as described above, especially in the case of ground-penetrating radar, is configured to emit radio waves from the ground surface to the depth of the ground, so it is useful for, for example, mountain conservation and flood control management. In this case, it was not possible to effectively measure the most basic elements, such as the amount of infiltration into the ground due to rainfall, the amount retained, and their changes over time.

Particularly in Japan, where there are many areas with heavy rainfall and poor topographical conditions, although the above factors are extremely important, there is no effective alternative method, and it is mainly based on empirical external observation. I was estimating/judging them.

This invention was made in view of the above-mentioned conventional problems, particularly in the area of mountain and flood control management. intended to provide.

[Means to solve the problem]

Therefore, in the present invention, an electromagnetic wave generation/transmission unit each having a transmitting antenna and an electromagnetic wave receiving unit having a receiving antenna are paired, and the medium to be measured is arranged such that both antennas face each other at an appropriate interval. Quantitatively analyze specific physical properties of the medium, such as the amount of water seeping into the ground, by embedding the antenna in the medium and measuring the propagation speed of the electromagnetic wave and waveform disturbance between the two antennas. The aim is to achieve the above objective by configuring a system that allows the following.

[Effect]

With the above-described system configuration, by embedding and measuring each pair of transmitting/receiving units at a desired depth in the medium to be measured, specific physical properties of this part in the medium can be determined, e.g. , it is possible to quantitatively know the distribution of the amount of underground water seepage and other information.

(Example) The present invention will be explained below based on examples.

(System Configuration) FIG. 1 shows a schematic diagram of the system configuration of an example in which the principles of this invention are applied to measuring the amount of underground infiltration caused by rainfall. E is the underground where moisture has permeated due to rainfall, which is the medium to be investigated.
G indicates the ground.

A T / A n are a pair of transmitting/receiving antennas, each buried at a depth d in the ground E so as to face each other horizontally with an interval p between them.
n is attached to the transmitter/receiver T/R to form each unit, and each unit A/T, A,/R
are each drip-proof/water-proof sealed.

On the other hand, 1 is a signal installed on the ground! The IJ control/processing means is connected to each transmitter/receiver T/R by a lead wire 2.

FIG. 2 is a block diagram showing details of an example of the system configuration. The transmitter T includes a pulse generating circuit and a transmitting circuit, while the receiver R includes a pulse receiving circuit and a sampling circuit. Reference numeral 3 denotes a control circuit disposed relatively close to the ground surface G, which controls pulse generation, synchronization of transmission/reception, and the like. 4 includes a frequency conversion circuit for signal processing, and 5 includes an analog display circuit, an A/D conversion circuit, and the like.

Reference numeral 6 indicates a data transmission circuit, and reference numeral 7 indicates data processing/analysis software, both of which are configured to be capable of remote communication/control via wires or wirelessly via each antenna 8.

(Embedding Procedure) FIGS. 3(a), (b), and (c) show process charts of an example of the underground burying procedure of each transmitting/receiving unit. Although the figure illustrates a horizontal surface, it goes without saying that the surface may be on a slope such as an actual mountain forest.

First, in figure (a), a predetermined distance p(
For example, a pair of vertical holes 10 are cut at a distance of 1.0 to 1.5 m) and are slightly deeper (α) than a predetermined ground depth (d) at which each antenna is to be installed.

Reference numeral 11 represents the topsoil portion to be removed first, and the excavated surface is preserved without being dispersed for later backfilling.

Next, as shown in Figure (b), the transmitting/receiving antennas T/R of each unit are separated from the bottom of each unit, and are placed in close contact with the wall surface so that they face each other in the water. Backfill to the bottom (indicated by 12). (c) As shown in the figure, both holes are completely backfilled (indicated by 13), and each lead wire 2 is connected to the control 2/processing means 1 on the ground.

(Other burying methods) Example 1-2 shows a case in which the transmitting/receiving unit was left buried for a certain period of time to obtain temporal data, but this is not limited to just kneading. For example, as shown in the cross-sectional view of the main part in Fig. 4, an observation tube 20 of a predetermined length made of a non-magnetic material such as vinyl chloride that allows the passage of electromagnetic waves is embedded in advance, and transmission/reception can be performed as necessary. Set the unit 1. You can also set the unit. 20 is a waterproof cover, 22
2 shows the waterproof packing part of the Riet wire table extractor 1. Also, 23 is crushed stone filled in the bottom of the tube 20, and 24 is a non-magnetic net placed therein.

(Operation/effect) Next, the operation/effect in the system configuration as described above will be explained.

i′ of this system! 11 The constant principle is extremely tp pure, and the electromagnetic pulse radiated from the transmitting antenna A□ is
The time it takes to propagate p and reach the receiving antenna A7 (n
The purpose is to find out the effect of attenuation due to infiltrated moisture on the propagation velocity V, which is unique to the soil of the target area, by measuring the s order.

In this case, the external factors that affect the propagation velocity V of electromagnetic waves are generally infiltration water due to rainfall and changes in water content due to long-term dryness, but in a country like Japan, the latter Since the influence of is practically negligible except in specific areas, the delay in the above time due to the increase in water content caused by the navigator, that is, the change in the decrease in the propagation speed (attenuation rate), is calculated, and the unique propagation Speed ■. Which comparison data can be used to quantitatively determine the amount of penetration, and it is also easy to display this directly in analog or digital form.
By burying a desired number of unit pairs and collecting data over time, it is possible to know the quantitative distribution and temporal changes in water content.

(Application example) By using the data on temporal changes in water content in each area as described above, for example, by determining the difference between precipitation (this measurement is extremely easy to obtain using conventional methods) and the amount of seepage water. , it becomes possible to estimate the actual amount of water held by water sources, etc.

In addition, by determining the difference between the infiltration time, the amount of infiltrated water, and the amount of water flowing out to the water source, it is possible to estimate the saturation state of water in the water in the target area, and this can be used, for example, to predict the degree of danger in areas above ground. obtain.

Furthermore, if necessary, various physical properties such as the density, degree of consolidation, and cohesive force of the soil at that point in time can be known from the moisture content.

By utilizing the effects like -V, it becomes possible to use it for a wide range of clogging applications, such as -F2.

1) Investigation of rainfall infiltration ■ Surface land conservation ■ Measurement of changes in moisture content in forest land / Forest land conservation management ■ Investigation related to groundwater ■ Investigation of snowmelt water infiltration, etc. 2) Investigation of moisture content variables ■ Effect of watering in dry areas Investigation - Maintenance management of sand, embankments, etc. The principle of this invention is applicable not only to moisture measurement as described above, but also to other methods such as management of grains, feed, etc. in silos and transport ships. It can also be extended to measurement of the amount of media present.

〔Effect of the invention〕

-1 As explained, according to this inventive system,
Since each pair of electromagnetic wave transmitting/receiving units is buried at a desired depth in the medium to be measured and is configured to measure the propagation velocity of the electromagnetic wave, it is possible to measure the specific physical properties of the medium in this part, for example, underground. It has become possible to quantitatively measure the amount of permeated water, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an embodiment of the underground percolation water measuring system according to the present invention, FIG. 2 is a detailed block diagram of an example of the device configuration, and FIG. 3(a). (b) and (c) are process diagrams of an example of underground burying means for each transmitting/receiving unit, and FIG. 4 is a sectional view of a main part showing an example of another burying method. T/R...Transmitter/Receiver A T/A *...Transmitting/receiving antenna E
−−−−−−Underground (medium) d/p−・・・・Predetermined depth/interval ■・・・・・・
Propagation velocity Applicant Green Technology Co., Ltd. Figure 1 Figure 3 (b) ■ Brush Figure 4

Claims (1)

[Claims] An electromagnetic wave generating/transmitting means having a transmitting antenna and the electromagnetic wave receiving means having a receiving antenna are buried as a pair in a target medium to be measured at a predetermined depth so that both antennas face each other at an appropriate interval, By measuring the propagation speed of the electromagnetic wave between the two antennas, waveform disturbance, etc., it is possible to quantitatively analyze specific physical properties of the medium, such as the amount of water seeping into the ground, etc. Features: A measurement system for underground water seepage, etc.