KR101651536B1 - System for evaluating compaction degree of railway roadbed using tdr (time domain reflectometry),and method for the same - Google Patents

Abstract

By using Time Domain Reflectometry (TDR), it is possible to quickly and accurately evaluate the geotechnical characteristics of reliable soil with water content and dry density, which is an integral part of the roadbed, and to provide a flat strip TDR probe integrated in the TDR system, There is provided a system and method for estimating railway roadbed roughness using TDR which can easily measure and evaluate on-site railway road surface roughness in a state in which a TDR system is carried, without the necessity of intrusion into a railway roadbed.

Description

TECHNICAL FIELD [0001] The present invention relates to a system and method for estimating railroad roadbed roughness using TDR,

More particularly, the present invention relates to a system and method for evaluating a railway roadbed roughness using TDR (Time Domain Reflectometry) in order to evaluate a compaction degree of a railway roadbed.

In general, compaction is performed so that excessive settlement does not occur due to the structure or other external environmental factors when the embankment is constructed to construct the structure on the ground. Such compaction can be performed not only on the clay ground but also on the existing ground.

After carrying out such a compaction operation, it is necessary to carry out compaction quality control to judge whether the compaction work has been sufficiently performed, for example, whether the compaction work has been properly adapted to the structure of the embankment. Such compaction quality control can have a significant impact on subsequent processes, such as the stability of the structure.

At this time, it is important to accurately measure the compaction degree in the quality control of the compaction of the ground. Compaction refers to increasing the dry density (or dry unit weight) of the soil by bringing the soil particles close to each other by applying a constant pressure to the soil, and since the compaction of the soil changes depending on the water content of the soil, It is very important to know the optimum water content and maximum dry density of the soil to be measured. For example, when compaction is performed while varying the water content ratio of the soil under the same conditions, there is a point at which the drying density becomes maximum in each water content ratio. Also, the drying density may vary depending on the degree of compaction at the same water content.

 As described above, there is a point where the largest value of the dry density, that is, the dry density is the maximum, at which the dry density becomes maximum in each water content. That is, the water content at the point at which the largest dry density value is reached (when the dry density becomes maximum) is referred to as "optimum water content", and the dry density obtained at the optimum water content is referred to as "maximum dry density".

The maximum dry density is generally measured in the form of a sample using the soil in the field, a compaction step in which the water content of the sampled soil is varied, and a compaction test in which the relationship between the dry density according to the water content ratio is determined Lt; / RTI >

When the maximum drying density is obtained through this compaction test, the compaction operation is performed in the field. Compaction is carried out on site by comparing the maximum dry density ("maximum dry density obtained from the compaction test") obtained by the test by measuring the dry density of the field ground where such compaction has been performed ("dry density of the site") Relative compaction of a ground can be obtained.

On the other hand, it is the domestic situation that the design and construction technology follow the past technology in comparison with other fields, which is the main component of the road and railroad. In general, the soil moisture content and dry density are important factors in managing the quality of compaction. In Korea, however, the road surface compaction assessment in the field is carried out by the conventional method (KSF 2312) (KSF 2310), and repeated loading tests. Such quality control of conventional compaction is not only economical but also may cause problems such as reduction of bearing capacity, settlement and crack due to unevenness of compaction in civil engineering structures and civil engineering works.

On the other hand, due to low reliability of compaction quality control in Korea, construction costs are wasted due to settlement and cracks in roads and railways. Therefore, in order to have high reliability and high quality management technology, it is necessary to convert from conventional compaction quality control to electronic quality control method, and technical experience should be accumulated within a few years. It is necessary. As a result, it is necessary to develop a TDR system that can measure road surface constants such as soil moisture content and dry density more economically and reliably, and can grasp the geotechnical characteristics of soil quickly and accurately. to be.

Also, securing the degree of compaction in civil engineering is very important as a fundamental part in carrying out the construction work. For example, quality control of compaction used in many works such as retaining walls, dams, banks, roads and railways is a basic task, but in Korea, it tends to be neglected by quality control of conventional compaction. Such insufficient quality control can lead to deterioration of civil structure and uneven settlement of roads and railways, which may cause a lot of human and property damage. Therefore, in order to prevent damage from poor quality control, quality control of domestic compaction should be improved by analyzing the propagation behavior of the soil and inherent electromagnetic waves in the conventional manner following the technology in the past, to improve the quality control of reliable electronic compaction.

Recently, in order to solve these problems, the United States and Europe have been studying a method of easily obtaining the design constants related to the compaction of the bedrock, and as a representative method thereof, there are a nuclear measuring device (Nuclear Guage) and a time domain reflectometry Reflectometer) is used. However, since the use of Nuclear Guage is inferior due to the risk of radioactive isotopes, the use of TDR, which has no risk of radioisotope, is increasing. As a result of the advanced study of TDR, high quality reliability of road and rail road compaction should be secured.

In recent years, research on TDR has been carried out in the United States and Australia. Recently, a theoretical formula for measuring the volumetric water content has been established. In addition, recently, ASTM TDR method considering geotechnical characteristics has been developed, Studies on TDR to measure dry density have been actively conducted.

In addition, it is proved experimentally that the elastic modulus measurement method using the bender element is applied for the first time in the field of soil mechanics, and the similar maximum shear modulus value is obtained through the test of the bending element and the test of the bender element. .

For example, in Korea, test and calibration tests were carried out on the function sensor under the road using the TDR sensor for coating thickness, influence of inter-sensor interference, influence of temperature, and compaction ratio, and distributed TDR sensor A distributed TDR metrology system was used to verify the depth function of large - scale embankment.

Recently, a technique has been developed for laying the foundation for quick and easy compaction quality control standards for clay soils and roads by measuring the water content and density of clay soils using TDR system

However, according to the related art, there is a problem that the TDR probe is manufactured in a rod shape so that it can be intruded into the railway roadbed, and such a rod-shaped TDR probe is not integrated with the TDR system and must be carried separately.

Korean Patent No. 10-1269325 filed on September 28, 2012, entitled "TDR measurement line and TDR measurement system equipped with it" Korean Patent No. 10-1330828 filed on June 25, 2012, entitled "Water content meter for measuring water content of concrete" Korean Patent Publication No. 2010-20711 (Published on Feb. 23, 2010), entitled "Method for Measuring Compaction Quality of Railroad Tracks" Korean Registered Patent No. 10-974892 filed on Aug. 1, 2008, entitled "Method for Measuring Compaction Quality of Soil" Korean Patent No. 10-1242681 filed on Aug. 26, 2010, entitled "Apparatus for Measuring Relative Density of Embankment Layer and Method for Measuring Relative Density of Embankment Layer Using It" Korean Registered Patent No. 10-643055 filed on June 24, 2005, entitled "Compaction degree management and road bed evaluation system" No. 10-1134075 filed on October 13, 2009, entitled " Device for Providing Continuous Compaction Information of Ground According to Movement of Ground Compaction Equipment and Method for Providing Continuous Compaction Information of Ground Using the Device "

The present invention has been made to solve the above-mentioned problems. It is an object of the present invention to provide a railroad roadbed grading system using TDR, which can quickly and accurately evaluate the geotechnical characteristics evaluation of reliable soil having water content and dry density, Evaluation system and method therefor.

It is another object of the present invention to provide a TDR system that does not require a flat strip TDR integrated in a TDR system to be attached to a lower portion of a housing box, The present invention provides a system and method for evaluating railway roadbed roughness using TDR, which can easily measure and evaluate road surface roughness in the field.

According to an aspect of the present invention, there is provided a system for evaluating railway roadbed roughness using a TDR, comprising: a flat strip TDR probe installed on a surface of a railway roadbed on which compaction is performed; A waveform generator for propagating an input signal through a coaxial cable connected to said flat strip TDR probe; A data acquisition unit receiving a reflected signal from the flat strip TDR probe; An oscilloscope for displaying the input signal and the reflection signal; A data storage unit for storing the input signal and the reflection signal; A dielectric constant and a volume electrical conductivity estimator for estimating a dielectric constant and a volume electrical conductivity according to an input signal and a reflection signal stored in the data storage; A water content and dry density calculating unit for calculating a water content and a dry density corresponding to the estimated dielectric constant and the volume electrical conductivity; And a railway roadbed roughness evaluation unit for evaluating a railway roadbed roughness degree according to the calculated moisture content and dry density, wherein the flat strip TDR probe is provided in a flat strip shape on the surface of a railway roadbed, Attached to the bottom of the box is the complete nondestructive testing without penetration,
The oscilloscope of the waveform generator, the flat strip TDR probe, the data acquisition unit, and the compaction degree evaluation apparatus is built in the housing box formed of EPS foam or a lightweight material, and measures the railroad road surface roughness And evaluating the results.

Here, the housing box may be formed of EPS foam or a lightweight material.

Here, the data storage unit, the dielectric constant and the volumetric conductivity estimator, the water content and dry density calculator, and the railroad roadbed roughness estimator may be embedded in a PC or a laptop computer.

According to another aspect of the present invention, there is provided a method for evaluating railroad roadbed roughness using a TDR, comprising the steps of: a) installing a flat strip TDR probe of a TDR device on a surface of a railway roadbed subjected to compaction; ; b) the waveform generator of the TDR device propagates an input signal through a coaxial cable connected to the flat strip TDR probe; c) receiving a reflected signal from the flat strip TDR probe by a data acquisition unit of the TDR apparatus; d) displaying the input signal and the reflected signal through an oscilloscope, and storing the input signal and the reflected signal in a data storage unit; e) estimating a dielectric constant and a volume electrical conductivity according to an input signal and a reflection signal stored in the data storage unit; f) calculating a moisture content and a dry density, which are integral with the bedrock state according to the correlation corresponding to the estimated dielectric constant and the volume electrical conductivity; And g) evaluating the railroad roadbed compaction degree according to the calculated moisture content and dry density, wherein the flat strip TDR probe of step a) is installed in the form of a flat strip on the surface of the railway roadbed, The test is carried out in a completely non-destructive manner,
The oscilloscope of the waveform generator, the flat strip TDR probe, the data acquisition unit, and the compaction degree evaluation apparatus is built in the housing box formed of EPS foam or a lightweight material, and measures the railroad road surface roughness And evaluating the results.

)는

로 주어지고, 여기서, a는 흙의 전파에 의해서 얻어지는 상수이고, b는 물의 전파에 의해서 구해지는 상수이며,

는 함수비를 나타내고,

는 물의 단위중량으로서 9.8

로 주어지고,

는 건조밀도를 나타내는 것을 특징으로 하는 TDR을 이용한 철도노반 다짐도 평가 방법.Here, in the step c), the dielectric constant (

)

Where a is a constant obtained by propagation of soil, b is a constant obtained by propagation of water,

Represents the water content,

Is 9.8 < RTI ID = 0.0 >

Lt; / RTI >

Wherein the dry density of the railroad tread is in the range of 1 to 10 mm.

Here, the constant a is given in the range of 0.95 to 1.2, and the constant b can be given in the range of 7.5 to 9.

)가 0인 건조토(dry soil) 일 때,

가 되고, 상기 함수비(

)가 100인 포화토(saturation soil) 일 때,

가 되며, 여기서,

는 포화토의 유전상수를 나타내고,

는 물의 유전상수를 각각 나타내는 것을 특징으로 한다.Here, the water content ratio (

) Is 0 dry soil,

, And the water content ratio (

) Is 100 saturation soil,

Lt; / RTI >

Represents the dielectric constant of the saturating soil,

Is a dielectric constant of water.

)은

로 주어지고, 여기서,

는 진공 전자기파 속도이고,

는 상기 펄스 발생기에서 생성되는 스텝 펄스의 2배전압이며,

는 장주기 전압레벨일 수 있다.Here, in step c), the volume electrical conductivity (

)silver

Lt; / RTI >

Is the vacuum electromagnetic wave velocity,

Is a voltage twice the step pulse generated by the pulse generator,

May be a long term voltage level.

Here, by comparing the optimum water content and the maximum dry density obtained by the compaction test in the step g), it is possible to evaluate the degree of compaction of the railway roadbed by obtaining the relative compaction degree of the ground subjected to compaction in the field.

According to the present invention, it is possible to quickly and accurately evaluate the geotechnical property evaluation of reliable soil having a moisture content and a dry density, which is an integral part of the road surface, using TDR. That is, the efficiency of the construction, the economical efficiency and the reliability can be easily secured through the quality control of the electronic compaction using the TDR system.

According to the present invention, a flat strip TDR probe integrated in a TDR system is attached to a lower portion of a housing box, so that it is not necessary to intrude into a railway roadbed. In addition, And can be easily measured and evaluated. In other words, by constructing the TDR probe in the form of a flat strip, solid gravel can be tested completely non-destructively on the upper layer, unlike the existing TDR system. And can be easily applied to domestic sites.

According to the present invention, it is possible to apply to various civil engineering works or various grounds, and the construction period can be shortened by judging quickly and accurately the degree of compaction.

1 is a block diagram of a railroad roadbed roughness evaluation system using TDR according to an embodiment of the present invention.
2 is a block diagram of a system for evaluating railway roadbed roughness using TDR according to an embodiment of the present invention.
3 is a diagram illustrating a TDR device in a railroad roadbed roughness evaluation system using TDR according to an embodiment of the present invention.
4 is a view showing a measurement probe in a railroad roadbed roughness evaluation system using TDR according to an embodiment of the present invention.
5 is a diagram illustrating a result of TDR propagation in a railroad roadbed roughness evaluation system using TDR according to an embodiment of the present invention.
6 is a flowchart illustrating a method of evaluating railway roadbed roughness using TDR according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. Also, the term "part" or the like, as described in the specification, means a unit for processing at least one function or operation, and may be implemented by hardware, software, or a combination of hardware and software.

[System for Evaluating Railroad Roadbed Compaction Using TDR (100)]

FIG. 1 is a block diagram of a system for evaluating a railroad roadbed roughness using a TDR according to an embodiment of the present invention, FIG. 2 is a block diagram of a railroad roadbed roughness evaluation system using a TDR according to an embodiment of the present invention, FIG. 4 is a view illustrating a measurement probe in a railroad roadbed roughness evaluation system using a TDR according to an embodiment of the present invention. FIG. 4 is a view illustrating a measurement probe in a railroad roadbed roughness degree evaluation system using a TDR according to an embodiment of the present invention.

Referring to FIG. 1, a system 100 for evaluating a railroad roadbed roughness using TDR according to an embodiment of the present invention includes a waveform generator 111, a flat strip TDR probe 112, a data acquisition unit 113, And the PC may be embodied as a PC oscilloscope 121 of the personal computer 120, and the components may be embedded in the housing box 101 for easy carrying. Here, the housing box 101 is preferably made of EPS foam or lightweight material.

1 to 4, a system 100 for evaluating a railway roadbed roughness using TDR according to an exemplary embodiment of the present invention is roughly implemented as a TDR apparatus 110 and a degree-of-compaction apparatus 120, The TDR apparatus 110 includes a waveform generator 111, a flat strip TDR probe 112 and a data acquisition unit 113. The apparatus 120 includes an oscilloscope 121, a data storage unit 122, A dielectric constant and volume electrical conductivity estimating unit 123, a water content and dry density calculating unit 124 and a railroad roadbed roughness evaluating unit 125. At this time, the data storage unit 122, the dielectric constant, The conductivity estimation unit 123, the water content and dry density calculation unit 124, and the railroad roadbed roughness evaluation unit 125 may be implemented as a microcontroller in a PC or a laptop computer.

The flat strip TDR probe 112 is installed on the surface of the railroad bed where the compaction is performed. The flat strip TDR probe 112 may be, but is not limited to, a flat strip TDR probe having a predetermined length, as shown in FIG. 4 described below. However, the TDR probe 112 according to the embodiment of the present invention may be attached to the bottom of the housing box 101 in the form of a flat strip so that the hard gravel Unlike the conventional TDR system, it is possible to perform the complete non-destructive test without penetrating the upper layer.

The waveform generator 111 propagates the input signal through a coaxial cable connected to the flat strip TDR probe 112, as shown in FIG. In this case, the waveform generator 111 may be a step generator or a TDR generator.

The data acquisition unit 113 receives the reflection signal from the flat strip TDR probe 112.

In addition, the oscilloscope 121 displays the input signal and the reflection signal, and the data storage unit 122 stores the input signal and the reflection signal. The oscilloscope 121 may be an external type connected to the TDR device 110. In the embodiment of the present invention, the oscilloscope 121 may be a personal computer (PC) oscilloscope 121 ). At this time, the input signal and the reflection signal can be stored in an Excel file format, but are not limited thereto.

The dielectric constant and volume electrical conductivity estimating unit 123 estimates the dielectric constant and the volume electrical conductivity according to the input signal and the reflection signal stored in the data storage unit 122, respectively.

The water content and dry density calculator 124 calculates the bedrock state constant, which is the moisture content and the dry density, corresponding to the estimated dielectric constant and the volume electrical conductivity.

The railway roadbed roughness evaluation unit 125 evaluates the railway roadbed roughness according to the calculated water content and dry density. That is, the railroad roadbed roughness degree evaluation unit 125 can evaluate the degree of compaction of the railway roadbed by comparing the relative moisture content of the ground subjected to compaction in the field by comparing the optimum water content and the maximum dry density obtained by the compaction test.

), 건조밀도(

)의 신뢰성 있는 흙의 지반공학적 특성 평가를 신속하고 정확하게 평가할 수 있다. 또한, TDR 시스템에 일체화된 플랫스트립(Flat Strip) TDR 탐침을 하우징 박스의 하부에 부착하여 사용함으로써 철도노반에 관입시킬 필요가 없고, TDR 시스템을 휴대한 상태에서 철도노반 다짐도를 현장에서 간편하게 측정 및 평가할 수 있다.As a result, the system for evaluating the railway roadbed roughness using DR according to the embodiment of the present invention calculates the water content

), Dry density (

) Can be evaluated quickly and accurately. In addition, the Flat Strip TDR probe integrated in the TDR system can be attached to the bottom of the housing box, eliminating the need to enter the railway roadbed. The TDR system can be easily measured and measured in the field while carrying the TDR system. Can be evaluated.

) 및 건조밀도(

)를 산출하는 과정을 구체적으로 설명하기로 한다.Hereinafter, the TDR is used to determine the water content

) And dry density (

) Will be described in detail.

First, TDR (Time Domain Reflectometry) is an electrical measuring device for measuring the electrical signal echo time of the flat strip TDR probe 112 installed in the soil using the electric conduction characteristic of the electric signal. The characteristics of the electromagnetic waves reflected by the impedance changes of the medium around the coaxial cable 114 and the flat strip TDR probe 112 during propagation through the coaxial cable 114 and the flat strip TDR probe 112 installed on the surface of the soil The basic principle is to measure the dielectric constant of soil.

)와 플랫스트립 TDR 탐침(112)의 길이(

)를 통하여 유전상수(

)를 구하기 위한 수학식 1은 다음과 같이 주어진다.Specifically, with respect to this TDR, the distance between two radio waves

) And the length of the flat strip TDR probe 112 (

Lt; RTI ID = 0.0 > (

) ≪ / RTI > is given as follows.

)와 흙의 체적 함수량(

)의 상관관계를 통하여 이론식에 의한 관계가 성립됨을 증명하고 있고, 함수비(

)를 구할 수 있는 수학식 2 및 수학식 3은 다음과 같다.This equation (1) shows the dielectric constant

) And volumetric water content of soil (

), And it is proved that the relation by the theoretical formula is established through the correlation of

(2) and (3) are as follows.

는 물의 단위중량으로서, 9.8

로 주어지고,

는 건조밀도를 나타낸다.here,

Is 9.8 < RTI ID = 0.0 >

Lt; / RTI >

Represents the dry density.

)와 유전상수(

)의 상관관계에 있어 많은 오차가 발생됨이 연구를 통하여 증명되었다. 이에 따라 보다 정밀하게 현장 흙에 대한 계산을 통하여 a, b 상수를 얻음으로써, TDR로 측정된 유전상수와 건조밀도의 상관관계를 이용한 관계식은 다음과 같이 수학식 4로 주어질 수 있다.According to Equations (2) and (3), satisfactory volumetric water content within the tolerance range of general soil was obtained, but the volumetric water content of soil in organic soil, fine clay soil and clay

) And dielectric constant (

) Were found to be correlated with each other. Accordingly, by obtaining the a and b constants more precisely through the calculation of the soil in the field, the relational expression using the correlation between the dielectric constant and the dry density measured by TDR can be given by Equation (4) as follows.

)가 0인 건조토(dry soil) 일 때,

가 되고, 함수비(

)가 100인 포화토(saturation soil) 일 때,

가 된다. 따라서 상수 a는 흙의 전파에 의해서 얻어지는 상수이고, 상수 b는 물의 전파에 의해서 구해지는 상수이다. 여기서,

는 포화토의 유전상수를 나타내고,

는 물의 유전상수를 각각 나타낸다. 또한, 상기 상수 a는 0.95 내지 1.2의 범위로 주어지고, 상기 상수 b는 7.5 내지 9의 범위로 주어질 수 있다.Here,

) Is 0 dry soil,

, And the water ratio (

) Is 100 saturation soil,

. Therefore, the constant a is a constant obtained by propagation of soil, and the constant b is a constant obtained by propagation of water. here,

Represents the dielectric constant of the saturating soil,

Represents the dielectric constant of water, respectively. Also, the constant a is given in the range of 0.95 to 1.2, and the constant b can be given in the range of 7.5 to 9.

)은 TDR 전압크기와 관련이 있고, 이때, 체적전기전도율(

)은 다음의 수학식 5와 같고, 그 결과는 도 1에 도시된 바와 같다. 여기서, 도 5는 본 발명의 실시예에 따른 TDR을 이용한 철도노반 다짐도 평가 시스템에서 TDR 전파 결과를 예시하는 도면이다.Further, the volume electrical conductivity obtained from the TDR propagation (

) Is related to the TDR voltage magnitude, where the volumetric conductivity (

) Is as shown in the following equation (5), and the result is as shown in Fig. 5 is a diagram illustrating a TDR propagation result in a railroad roadbed roughness evaluation system using TDR according to an embodiment of the present invention.

는 진공 전자기파 속도이고,

는 상기 펄스 발생기에서 생성되는 스텝 펄스의 2배전압이고,

는 장주기 전압레벨이다.here,

Is the vacuum electromagnetic wave velocity,

Is a voltage twice the step pulse generated by the pulse generator,

Is a long-term voltage level.

)와 함수비(

)를 보다 정밀하게 구할 수 있는 수학식 6 및 수학식 7이 다음과 같이 주어질 수도 있다.On the other hand, the dry density (

) And water content (

(6) and (7), which can be obtained more precisely, may be given as follows.

), 건조밀도(

)를 신속 정확하게 측정할 수 있다. 또한, TDR 시스템에 일체화된 플랫스트립(Flat Strip) TDR 탐침을 하우징 박스의 하부에 부착하여 사용함으로써 철도노반에 관입시킬 필요가 없고, TDR 시스템을 휴대한 상태에서 철도노반 다짐도를 현장에서 간편하게 측정 및 평가할 수 있다.According to the embodiment of the present invention, the TDR is used to calculate the water content

), Dry density (

) Can be measured quickly and accurately. In addition, the Flat Strip TDR probe integrated in the TDR system can be attached to the bottom of the housing box, eliminating the need to enter the railway roadbed. The TDR system can be easily measured and measured in the field while carrying the TDR system. Can be evaluated.

[Method for Evaluating Railway Roadbed Compaction Using TDR]

6 is a flowchart illustrating a method of evaluating railway roadbed roughness using TDR according to an embodiment of the present invention.

Referring to FIGS. 2 and 6, a method for evaluating railroad roadbed roughness using a TDR according to an embodiment of the present invention includes: firstly, applying a flat strip TDR probe 112 of a TDR apparatus 110 to a compaction- (S110). At this time, the flat strip TDR probe 112 according to the embodiment of the present invention is attached to the bottom of the housing box 101 in the form of a flat strip, so that hard gravel is not penetrated in the upper layer unlike the existing TDR system The test can be done completely nondestructive.

Next, the waveform generator 111 of the TDR device 110 propagates the input signal through the coaxial cable 114 connected to the flat strip TDR probe 112 (S120).

Next, the data acquisition unit 113 of the TDR apparatus 110 receives a reflection signal from the flat strip TDR probe 112 (S130).

Next, the input signal and the reflected signal are displayed through the oscilloscope 121 and stored in the data storage unit 122 (S140).

Next, the dielectric constant and the volume electrical conductivity are estimated according to the input signal and the reflection signal stored in the data storage unit 122 (S150).

)는

로 주어지고, 여기서, a는 흙의 전파에 의해서 얻어지는 상수이고, b는 물의 전파에 의해서 구해지는 상수이며,

는 함수비를 나타내고,

는 물의 단위중량으로서 9.8

로 주어지고,

는 건조밀도를 나타낸다. 또한, 상기 함수비(

)가 0인 건조토(dry soil) 일 때,

가 되고, 상기 함수비(

)가 100인 포화토(saturation soil) 일 때,

가 되며, 여기서,

는 포화토의 유전상수를 나타내고,

는 물의 유전상수를 각각 나타낸다. 이때. 상기 상수 a는 0.95 내지 1.2의 범위로 주어지고, 상기 상수 b는 7.5 내지 9의 범위로 주어지질 수 있다.At this time, the dielectric constant (

)

Where a is a constant obtained by propagation of soil, b is a constant obtained by propagation of water,

Represents the water content,

Is 9.8 < RTI ID = 0.0 >

Lt; / RTI >

Represents the dry density. Further,

) Is 0 dry soil,

, And the water content ratio (

) Is 100 saturation soil,

Lt; / RTI >

Represents the dielectric constant of the saturating soil,

Represents the dielectric constant of water, respectively. At this time. The constant a is given in the range of 0.95 to 1.2, and the constant b is given in the range of 7.5 to 9. [

)은

로 주어지고, 여기서,

는 진공 전자기파 속도이고,

는 상기 펄스 발생기에서 생성되는 스텝 펄스의 2배전압이며,

는 장주기 전압레벨일 수 있다.Further, the volume electrical conductivity (

)silver

Lt; / RTI >

Is the vacuum electromagnetic wave velocity,

Is a voltage twice the step pulse generated by the pulse generator,

May be a long term voltage level.

이고,

로 주어질 수 있다.Next, the water content and the dry density corresponding to the estimated dielectric constant and the volume electrical conductivity are calculated (S160). For example,

ego,

Lt; / RTI >

Next, the railway road surface roughness is evaluated according to the calculated water content and dry density (S170). In other words, by measuring the water content and dry density of the on-site ground where the compaction is performed, comparing the optimum water content and the maximum dry density obtained by the compaction test, the compaction degree of the ground subjected to the compaction in the field is obtained and the degree of compaction of the railroad roadbed is evaluated .

), 건조밀도(

)를 신속 정확하게 측정할 수 있다. 또한, TDR 시스템에 일체화된 플랫스트립(Flat Strip) TDR 탐침을 하우징 박스의 하부에 부착하여 사용함으로써 철도노반에 관입시킬 필요가 없고, TDR 시스템을 휴대한 상태에서 철도노반 다짐도를 현장에서 간편하게 측정 및 평가할 수 있다.As a result, according to the embodiment of the present invention, by using the TDR,

), Dry density (

) Can be measured quickly and accurately. In addition, the Flat Strip TDR probe integrated in the TDR system can be attached to the bottom of the housing box, eliminating the need to enter the railway roadbed. The TDR system can be easily measured and measured in the field while carrying the TDR system. Can be evaluated.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

100: Railway roadbed compaction assessment system using TDR
101: Housing box
110: TDR device
120: Compensation evaluation device (PC)
111: Waveform generator
112: Flat Strip TDR Probe
113: Data acquisition unit
114: Coaxial cable
121: Oscilloscope (for PC)
122: Data storage unit
123: Dielectric Constant and Volumetric Conductivity Estimation
124: water content and dry density calculation section
125: Railroad roadbed roughness evaluation unit

Claims (9)

A flat strip TDR probe 112 mounted on the surface of the compromised railroad bed;
A waveform generator 111 for propagating an input signal through a coaxial cable 114 connected to the flat strip TDR probe 112;
A data acquisition unit (113) for receiving a reflection signal from the flat strip TDR probe (112);
An oscilloscope 121 for displaying the input signal and the reflection signal;
A data storage unit 122 for storing the input signal and the reflection signal;
A dielectric constant and a volume conductivity estimating unit 123 for estimating a dielectric constant and a volume electrical conductivity according to an input signal and a reflection signal stored in the data storage unit 122;
A moisture content and dry density calculation unit (124) for calculating a water content and a dry density corresponding to the estimated dielectric constant and the volume electrical conductivity; And
And a railway roadbed roughness evaluation unit (125) for evaluating a railway roadbed roughness degree according to the calculated moisture content and dry density,
The flat strip TDR probe 112 is a flat strip having a fork shape formed of a rectangular plate and is installed on the surface of a railway roadbed and is tested by performing a complete nondestructive test without attaching to the lower portion of the housing box 101,
The oscilloscope 121 of the waveform generator 111, the flat strip TDR probe 112 and the data acquiring unit 113 and the compaction degree estimating apparatus 120 may be an EPS form or a light- And the railroad roadbed roughness is measured and evaluated in the field in a state in which the railroad roadbed is built in the box (101). delete The method according to claim 1,
The data storage unit 122, the dielectric constant and volumetric conductivity estimator 123, the water content and dry density calculator 124, and the railroad roadbed roughness estimator 125 are embedded in a PC or a laptop computer Estimation System of Railroad Roadbed Using TDR. a) providing a TDR flat strip TDR probe 112 in the form of a flat strip on the compaction surface of the railway bed;
b) a waveform generator (111) of the TDR device (110) propagates an input signal through a coaxial cable connected to the flat strip TDR probe (112);
c) receiving the reflection signal from the flat strip TDR probe 112 by the data acquisition unit 113 of the TDR apparatus;
d) displaying the input signal and the reflected signal through an oscilloscope, and storing the input signal and the reflected signal in a data storage unit;
e) estimating a dielectric constant and a volume electrical conductivity according to an input signal and a reflection signal stored in the data storage unit;
f) calculating a moisture content and a dry density, which are integral with the bedrock state according to the correlation corresponding to the estimated dielectric constant and the volume electrical conductivity; And
g) evaluating the railway roadbed compaction degree according to the calculated water content and drying density
, ≪ / RTI &
The flat strip TDR probe 112 in the step a) is formed in the form of a flat strip having a fork shape made of a rectangular plate and is installed on the surface of the railway roadbed and attached to the lower portion of the housing box 101, Lt; / RTI >
The oscilloscope 121 of the waveform generator 111, the flat strip TDR probe 112 and the data acquiring unit 113 and the compaction degree estimating apparatus 120 may be an EPS form or a light- A method for evaluating railway roadbed roughness using TDR, characterized by measuring and evaluating a railway roadbed roughness in a portable state while being built in a box (101). 5. The method of claim 4,
In the step c), the dielectric constant (

)

Where a is a constant obtained by propagation of soil, b is a constant obtained by propagation of water,

Represents the water content,

Is 9.8 < RTI ID = 0.0 >

Lt; / RTI >

Wherein the dry density of the railroad tread is in the range of 1 to 10 mm. 6. The method of claim 5,
Wherein the constant a is given in a range of 0.95 to 1.2, and the constant b is given in a range of 7.5 to 9. 15. A method for evaluating railway roadbed roughness using TDR, 6. The method of claim 5,
The water content ratio (

) Is 0 dry soil,

, And the water content ratio (

) Is 100 saturation soil,

Lt; / RTI >

Represents the dielectric constant of the saturating soil,

Is a dielectric constant of water. The method of evaluating railway roadbed roughness using TDR. 5. The method of claim 4,
In step c), the volume electrical conductivity (

)silver

Lt; / RTI >

Is the vacuum electromagnetic wave velocity,

Is a voltage twice the step pulse generated by the waveform generator,

Is a long-term voltage level. 5. The method of claim 4,
The relative degree of compaction of the ground subjected to the compaction in the field is evaluated by comparing the optimum water content and the maximum dry density obtained by the compaction test in the step g) to evaluate the degree of compaction of the railroad roadbed using the TDR Way.

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