JP4442914B1 - Non-destructive investigation method for internal damage of pavement - Google Patents
Non-destructive investigation method for internal damage of pavement Download PDFInfo
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Abstract
【課題】舗装の内部損傷箇所を非破壊で迅速に定量調査できる方法を提供する。
【解決手段】上記課題は、舗装路面Ｒにおける検出対象領域の全体にわたり所定の間隔で、電磁波レーダーｋによる探査を行い、各反射波検出位置４０における反射波データ５０を取得し、この反射波データ５０に基づき、各反射波検出位置４０の所定深さにおける反射波強度５５を取得し、この反射波強度５０が所定の強度しきい値以上となる反射波検出位置４０を内部損傷箇所とし、且つ反射波強度が所定の強度しきい値未満となる反射波検出位置４０を非内部損傷箇所として、検出対象領域に占める内部損傷箇所の割合を定量化する、ことを特徴とする舗装の内部損傷箇所の非破壊調査方法により解決される。
【選択図】図１２The present invention provides a method capable of non-destructive and quick quantitative investigation of an internally damaged portion of pavement.
An object of the present invention is to search the electromagnetic wave radar k at a predetermined interval over the entire detection target region on the paved road surface R, obtain reflected wave data 50 at each reflected wave detection position 40, and obtain the reflected wave data. 50, the reflected wave intensity 55 at a predetermined depth of each reflected wave detection position 40 is acquired, and the reflected wave detection position 40 at which the reflected wave intensity 50 is equal to or greater than a predetermined intensity threshold is used as an internal damage point. An internally damaged portion of the pavement characterized by quantifying the proportion of the internal damaged portion in the detection target area, with the reflected wave detection position 40 where the reflected wave intensity is less than a predetermined intensity threshold as a non-internal damaged portion It is solved by the non-destructive investigation method.
[Selection] Figure 12
Description
本発明は 舗装の内部損傷箇所、例えば表面からは確認できない又は確認し難いひび割れ、層間剥離、滞水箇所等を、非破壊で調査する方法に関するものである。 The present invention relates to a method for nondestructively investigating internally damaged portions of pavement, such as cracks, delamination, and stagnant portions that cannot be confirmed or difficult to confirm from the surface.
舗装の性能はその供用に伴い低下するものである。よって、一般的な舗装管理においては、舗装の現況を適時に調査し、路面性能や舗装自体の強度がある程度まで低下したならば、舗装の維持（路面性能の回復及び舗装の構造的強度低下の遅延）又は修繕を行うといったことが実施されている。 The performance of pavement decreases with its service. Therefore, in general pavement management, the current state of pavement is investigated in a timely manner, and if the road surface performance and the strength of the pavement itself have decreased to a certain extent, maintenance of the pavement (recovery of road surface performance and reduction of the structural strength of the pavement) Delays) or repairs are being implemented.
このような舗装管理において、舗装の現況調査はその後の維持・修繕計画の指標となるため極めて重要であり、既設舗装の状態を正確に把握する必要がある。我が国における調査の種類には、簡易調査、路面の定量調査、破損原因の調査、及び利用者等の意見調査等があり、中でも定量調査は、管理目標値の設定により数値的且つ客観的な管理を行うことができるため、現在の舗装管理では欠かせないものとなっている。ここで、路面の定量調査では、次の（ａ）〜（ｅ）の調査を行うことが一般的となっている。
（ａ）ひび割れ率・ひび割れ度：スケッチ又は路面性状測定車により行う。
（ｂ）わだち掘れ量：横断プロフィルメータや路面性状測定車により行う。
（ｃ）平坦性：３メートルプロフィルメータまたは同等の結果が得られる方法により行う。
（ｄ）浸透水量：現場透水量試験により行う。
（ｅ）その他：すべり抵抗値、騒音値、ポットホール（長径、短径、個数）。
In such pavement management, pavement status surveys are extremely important because they serve as indicators for subsequent maintenance and repair plans, and it is necessary to accurately grasp the state of existing pavements. The types of surveys in Japan include simple surveys, quantitative surveys of road surfaces, surveys of causes of damage, and surveys of opinions of users, etc. Among them, quantitative surveys are numerical and objective management by setting management target values. This is an essential part of the current pavement management. Here, in the road surface quantitative survey, the following surveys (a) to (e) are generally performed.
(A) Cracking rate / cracking degree: A sketch or a road surface property measuring vehicle is used.
(B) Rudder digging amount: Performed with a crossing profilometer or road surface property measuring vehicle.
(C) Flatness: Performed by a 3 meter profilometer or a method that gives equivalent results.
(D) Permeated water amount: Performed by on-site water permeability test.
(E) Others: Slip resistance value, noise value, pothole (long diameter, short diameter, number).
これらの測定結果をそのまま用いて路面性能を評価しても良いが、いくつかの項目に基づく評価式を用いて性能評価を行うことが行われており、代表的なものとして、下記のＭＣＩ（維持管理指数）やＰＳＩ（供用性指数）、空港舗装におけるＰＲＩ（空港舗装供用性指数）がある。
MCI = 10 - 1.48C0.3 - 0.29D0.7 - 0.47σ0.2 …（1）
MCI0 = 10 - 1.51C0.3 - 0.30D0.7 …（2）
MCI1 = 10 - 2.23C0.3 …（3）
MCI2 = 10 - 0.54D0.7 …（4）
PSI = 4.53 - 0.518logσC0.9 - 0.371C0.5 - 0.174D2 …（5）
ただし、
C：ひび割れ率（％）
D：わだち掘れ量の平均（MCI：mm，PSI：cm）
σ：平坦性（mm）
〔注〕ＭＣＩは、式（１）（平坦性が未測定の場合は式（２））、式（３）及び式（４）の算出結果のうち最小値をもってＭＣＩの値とする。
Although the road surface performance may be evaluated using these measurement results as they are, performance evaluation is performed using an evaluation formula based on several items. As a representative example, the following MCI ( Maintenance index), PSI (serviceability index), and airport pavement PRI (airport pavement serviceability index).
MCI = 10 - 1.48C 0.3 - 0.29D 0.7 - 0.47σ 0.2 ... (1)
MCI 0 = 10 - 1.51C 0.3 - 0.30D 0.7 ... (2)
MCI 1 = 10-2.23C 0.3 (3)
MCI 2 = 10-0.54D 0.7 … (4)
PSI = 4.53 - 0.518logσC 0.9 - 0.371C 0.5 - 0.174D 2 ... (5)
However,
C: Crack rate (%)
D: Average rutting amount (MCI: mm, PSI: cm)
σ: Flatness (mm)
[Note] MCI is the value of MCI with the minimum value of the calculation results of Formula (1) (Formula (2) when flatness is not measured), Formula (3), and Formula (4).
また、ＭＣＩ値と補修の必要性との関係、並びにＰＳＩ値と補修工法との関係は次のとおりである。
MCI値 ≧ ５ ：望ましい管理水準（補修不要）
MCI値 ≦ ４ ：補修の必要あり
MCI値 ≦ ３ ：早急に補修の必要あり
PSI値 ＝ ３〜２．１ ：表面処理
PSI値 ＝ ２〜１．１ ：オーバーレイ
PSI値 ＝ １〜０ ：打換え工
The relationship between the MCI value and the necessity of repair, and the relationship between the PSI value and the repair method are as follows.
MCI value ≧ 5: Desirable management level (repair not required)
MCI value ≦ 4: Needs repair
MCI value ≦ 3: Need immediate repair
PSI value = 3 to 2.1: Surface treatment
PSI value = 2 to 1.1: Overlay
PSI value = 1 to 0: Replacement work
通常の場合、定量調査と同時に又は必要に応じて単独での、破損原因の調査を行う。破損原因の調査としては、採取コアの観察調査、コアからのアスファルトの抽出及び性状試験調査、舗装構造の非破壊調査（ＦＷＤやベンケルマンビーム等を用いたたわみ量測定等）や開削調査などがあり、舗装構造の非破壊調査や開削調査は、下表に示すように、路面のひび割れの進行速度やひび割れの状態等に応じて実施される。そして、その調査結果に基づき、路面の破損状況、支持力、疲労抵抗性等により舗装構造の評価が行われる。舗装構造の評価方法としては、路面の破損状況にもとづく残存等値換算厚、ＦＷＤなどのたわみ測定装置で測定される表面たわみ、疲労度等の指標を用いて行う方法がある。 In the normal case, the cause of damage is investigated simultaneously with the quantitative investigation or as needed. The investigation of the cause of damage includes observation of the collected core, extraction of asphalt from the core and property test, non-destructive investigation of the pavement structure (measurement of deflection using FWD, Benkelman beam, etc.) and excavation investigation. Yes, as shown in the table below, non-destructive surveys and excavation surveys of pavement structures are carried out according to the progress of cracks on the road surface and the state of cracks. Based on the survey results, the pavement structure is evaluated based on the road surface damage, bearing capacity, fatigue resistance, and the like. As an evaluation method of the pavement structure, there is a method of using an index such as a remaining equivalent-converted thickness based on a road surface breakage condition, a surface deflection measured by a deflection measuring device such as FWD, and a fatigue level.
他方、これらの現況調査の結果、既設舗装の性能が管理上の目標値を下回っている場合や、近い将来に下回ることが予想される場合などには、舗装の維持、修繕が行われる。舗装の維持は局部的で軽度な修理を行うものであり、下表のとおり、日常的維持と予防的維持とがある。 On the other hand, as a result of these current surveys, paving is maintained and repaired when the performance of the existing pavement is below the management target value, or when it is expected to drop in the near future. The maintenance of the pavement involves local and minor repairs, and there are daily maintenance and preventive maintenance as shown in the table below.
予防的維持は、舗装構造の性能に大きな変状が現れる前に路面の性能回復を図るものであり、例えば下表のとおりである。 The preventive maintenance is intended to restore the performance of the road surface before a major change appears in the performance of the pavement structure, for example, as shown in the table below.
これらに対して、舗装の修繕は、維持では不経済もしくは十分な回復が期待できない場合に、建設時の性能程度に復旧することを目的として行うものであり、例えば下表のとおりである。 On the other hand, pavement repair is performed for the purpose of restoring the performance at the time of construction when maintenance is not economical or sufficient recovery cannot be expected, for example, as shown in the table below.
しかしながら、従来の舗装評価の定量調査においては、ひび割れ等の損傷箇所に重きを置いているにもかかわらず、舗装の表面に露見したひび割れ等の損傷箇所しか定量化していなかったため、調査精度の点で改善の余地があった。 However, in conventional quantitative surveys for pavement evaluation, although the damages such as cracks are emphasized, only the damages such as cracks exposed on the surface of the pavement have been quantified. There was room for improvement.
すなわち、例えば図１６に順を追って示したように、舗装はその供用に伴い疲労し、平坦性、わだち掘れ量、ひび割れの増加により構造の健全性が低下し、また路面性能が低下していく。また、随時、舗装の日常的な維持は行われる。そして、ひび割れの進行により、路盤に水が浸入し、路盤損傷が進行する段階になると、オーバーレイ工法等の表層補修が実施され、路面の定量調査においてはひび割れの無い新設時と同じ評価となる。 That is, for example, as shown in FIG. 16 in order, the pavement fatigues as it is used, and the soundness of the structure decreases due to the increase in flatness, rutting amount, and cracks, and the road surface performance also decreases. . In addition, daily maintenance of the pavement is performed from time to time. Then, when the crack progresses, water enters the roadbed and the roadbed damage progresses, and surface layer repair such as the overlay method is carried out. In the quantitative survey of the road surface, the evaluation is the same as when a new installation without cracks.
しかし、このような表層補修が実施され、表面から内部への水の浸入が防止されたとしても、内部のひび割れが補修されていないと、内部のひび割れが増殖し、路面に到達したり、路盤の損傷が進行したりすることにより、内部の損傷は進行しており、それにもかかわらず、従来の路面の定量調査を実施すると、ひび割れの無い新設時からの疲労と同じ評価となってしまう。もちろん、内部構造の詳細調査も実施できなくはないが、前述の表１に示す通り、表面のひび割れ率が低い場合には詳細調査の必要性が低いと判断され、内部構造の詳細調査は実施されないことが普通であった。 However, even if such surface repair is performed and water intrusion from the surface is prevented, if the internal cracks are not repaired, the internal cracks will proliferate and reach the road surface. However, when the conventional quantitative survey of the road surface is carried out, the same evaluation as the fatigue from the time of new installation without cracks is made. Of course, it is not impossible to conduct a detailed survey of the internal structure, but as shown in Table 1 above, if the surface crack rate is low, it is judged that the need for a detailed survey is low, and a detailed survey of the internal structure is conducted. It was normal not to be.
また、近年増加傾向にある排水性舗装は表層が多孔質であるため、表面のひび割れが発見され難く、対応が遅れ易い。よって、このような排水性舗装に従来の定量調査を適用した場合にも、調査精度の点で改善の余地があった。 In addition, since drainage pavement, which has been increasing in recent years, has a porous surface layer, it is difficult to find cracks on the surface and the response tends to be delayed. Therefore, even when a conventional quantitative survey is applied to such drainage pavement, there is room for improvement in terms of survey accuracy.
そして、これらの問題の原因を探ると、定量調査においては非破壊で広範囲を迅速に調査できることが望まれるのに対して、従来、舗装の内部構造に対してそのような調査を行いうるものが存在していないことが知見された。 And if the cause of these problems is investigated, it is desired that a quantitative survey can be conducted quickly and non-destructively, but in contrast, there are those that can perform such a survey on the internal structure of pavement. It was found that it did not exist.
そこで、本発明の主たる課題は、舗装内部の損傷箇所を非破壊で迅速に定量調査できる方法を提供することにある。 Then, the main subject of this invention is providing the method which can carry out a quantitative investigation quickly and nondestructively the damage location inside a pavement.
上記課題を解決した本発明は次記のとおりである。
＜請求項１記載の発明＞
舗装の内部損傷箇所を非破壊で定量調査する方法であって、
電磁波レーダーを用い、舗装路面における検出対象領域の全体にわたり、路面に沿う方向に所定の間隔を空けて、舗装上から舗装内へ電磁波を深さ方向に入射させるとともにその反射波を舗装上で検出することにより、各反射波検出位置における反射波データを取得し、
この取得した反射波データに基づき、前記各反射波検出位置の反射波データにおける舗装表面の反射波ピークと路盤被覆層下面の反射波ピークとの間の部分から、反射波強度の最大値を当該反射波検出位置の反射波強度の代表値としてそれぞれ取得するとともに、
前記取得した反射波データに基づき、舗装表面における反射波ピークより下側における反射波の総エネルギーを前記各反射波検出位置について算出し、
この総エネルギーが所定のエネルギーしきい値以下となる反射波検出位置を内部損傷箇所とするとともに、
総エネルギーが所定のエネルギーしきい値を超える反射波検出位置であって、且つ前記反射波強度の代表値が所定の強度しきい値以上となる反射波検出位置を内部損傷箇所とし、
総エネルギーが所定のエネルギーしきい値を超える反射波検出位置であって、且つ反射波強度の代表値が所定の強度しきい値未満となる反射波検出位置を非内部損傷箇所として、
前記検出対象領域に占める内部損傷箇所の割合を定量化する、
ことを特徴とする舗装の内部損傷箇所の非破壊調査方法。
The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
A non-destructive method for quantitatively investigating the internal damage of pavements,
Using an electromagnetic wave radar, electromagnetic waves are incident in the depth direction from the pavement into the pavement at a predetermined interval in the direction along the road surface over the entire detection target area on the pavement surface, and the reflected wave is detected on the pavement. By obtaining reflected wave data at each reflected wave detection position,
Based on the acquired reflected wave data, the maximum value of the reflected wave intensity is calculated from the portion between the reflected wave peak on the pavement surface and the reflected wave peak on the lower surface of the roadbed covering layer in the reflected wave data at each reflected wave detection position. While obtaining each as a representative value of the reflected wave intensity at the reflected wave detection position ,
Based on the acquired reflected wave data, the total energy of the reflected wave below the reflected wave peak on the pavement surface is calculated for each reflected wave detection position,
While the reflected wave detection position where this total energy is below a predetermined energy threshold is an internal damage location,
The reflected wave detection position where the total energy exceeds a predetermined energy threshold value, and the reflected wave detection position where the representative value of the reflected wave intensity is equal to or greater than the predetermined intensity threshold value is an internal damage location,
The reflected wave detection position where the total energy exceeds the predetermined energy threshold and the reflected wave detection position at which the representative value of the reflected wave intensity is less than the predetermined intensity threshold is defined as a non-internal damage location.
Quantifying the proportion of internal damage occupying the detection target area,
A non-destructive investigation method for internally damaged parts of pavements characterized by
（作用効果）
本発明者らは、いわゆる電磁波レーダーを利用することにより、舗装の内部損傷箇所を定量化できるとの知見を得て本発明をなすに至った。すなわち、舗装内部のひび割れ、層間剥離、滞水箇所、補修箇所等の内部損傷に電磁波が入射しようとすると、その一部は反射し、反射波として検出することができ、これらの損傷の無い部分からは反射波は検出されない。本発明では、この原理を利用して、舗装路面における検出対象領域の全体にわたり、路面に沿う方向に所定の間隔を空けて、舗装上から舗装内へ電磁波を深さ方向に入射させるとともにその反射波を舗装上で検出することにより、各反射波検出位置における反射波データを取得し、内部損傷箇所・非内部損傷箇所を判別し、検出対象領域に占める内部損傷箇所の割合を定量化する。よって、舗装の広範囲な検出対象領域における内部損傷箇所を非破壊で迅速に調査できるようになる。
(Function and effect)
The present inventors have obtained the knowledge that by using a so-called electromagnetic wave radar, it is possible to quantify the internal damage location of the pavement, and have made the present invention. In other words, if electromagnetic waves try to enter internal damage such as cracks, delamination, stagnant locations, repair locations, etc. inside the pavement, some of them will be reflected and can be detected as reflected waves, and these undamaged parts No reflected wave is detected. In the present invention, by utilizing this principle, electromagnetic waves are incident from the pavement into the pavement in the depth direction and reflected in the depth direction along the road surface over the entire detection target area on the pavement road surface. By detecting the wave on the pavement, the reflected wave data at each reflected wave detection position is acquired, the internal damage location / non-internal damage location is determined, and the ratio of the internal damage location in the detection target region is quantified. Therefore, it becomes possible to quickly investigate non-destructive internal damage points in a wide detection target area of the pavement.
特に、本発明では、各反射波検出位置の反射波データにおける舗装表面の反射波ピークと路盤被覆層下面の反射波ピークとの間の部分（つまり路盤被覆層の内部損傷によりピークが発生する可能性がある部分）から、反射波強度の最大値を当該反射波検出位置の反射波強度の代表値としてそれぞれ取得し、この代表値が所定の強度しきい値以上であるか、未満であるかにより内部損傷箇所・非内部損傷箇所を判別することにより、ある反射波検出位置に存在する内部損傷の深さと、他の反射波検出位置に存在する内部損傷の深さとが異なっていても、いずれか一方だけではなく、両方を加味して検出対象領域に占める内部損傷箇所の割合を定量化することができる。 In particular, in the present invention, the portion between the reflected wave peak on the pavement surface and the reflected wave peak on the lower surface of the roadbed coating layer in the reflected wave data at each reflected wave detection position (that is, a peak may occur due to internal damage of the roadbed coating layer). The maximum value of the reflected wave intensity is obtained as a representative value of the reflected wave intensity at the reflected wave detection position, and the representative value is greater than or less than a predetermined intensity threshold value. By distinguishing between internal damage locations and non-internal damage locations, the internal damage depth at one reflected wave detection position may be different from the internal damage depth at another reflected wave detection position. It is possible to quantify the proportion of internal damages in the detection target area by taking into account both of them and not only one.
ただし、アスファルト層又はコンクリート層のような均質な路盤被覆層内に、粒状に崩れた損傷部分が存在していると、その損傷部分に上方から入射した電磁波だけでなく、被覆層の下面から反射して戻ってくる電磁波も散乱し、結果的には舗装上では舗装内からの反射波を殆ど検出できない状態が発生する。よって、ひび割れ等のように単に反射波強度が強い部分を有する箇所を内部損傷箇所とするだけでは、このような損傷箇所は検出することができない。 However, if there is a damaged part broken into particles in a homogeneous roadbed covering layer such as an asphalt layer or a concrete layer, not only electromagnetic waves incident on the damaged part from above but also reflected from the lower surface of the covering layer. As a result, the returning electromagnetic wave is also scattered, and as a result, a state in which the reflected wave from the inside of the pavement can hardly be detected occurs. Therefore, such a damaged portion cannot be detected simply by setting a portion having a portion having a strong reflected wave intensity such as a crack as an internally damaged portion.
これに対して、上述のように舗装表面よりも下側における反射波の総エネルギーを利用し、総エネルギーが所定のエネルギーしきい値以下となるか否かを見れば、散乱により反射波が消失するような内部損傷があるか否かを精度良く判別することができる。そして、総エネルギーが所定のエネルギーしきい値を超える条件の下で、反射波強度の代表値に基づく内部損傷箇所の判別を行うことにより、より多くの種類の内部損傷を定量化することができるようになる。 On the other hand, if the total energy of the reflected wave below the pavement surface is used as described above and the total energy falls below a predetermined energy threshold, the reflected wave disappears due to scattering. It is possible to accurately determine whether or not there is internal damage. And by determining the internal damage location based on the representative value of the reflected wave intensity under the condition that the total energy exceeds the predetermined energy threshold, it is possible to quantify more types of internal damage. It becomes like this.
＜請求項２記載の発明＞
前記各反射波検出位置の反射波強度を、路面の多孔性及び湿潤状態の影響を排除するための補正係数を乗じて補正する、請求項１記載の舗装の内部損傷箇所の非破壊調査方法。
<Invention of Claim 2 >
The nondestructive investigation method for an internally damaged portion of the pavement according to claim 1, wherein the reflected wave intensity at each reflected wave detection position is corrected by multiplying by a correction coefficient for eliminating the influence of the porosity and wet state of the road surface.
（作用効果）
電磁波を舗装に向かって照射した場合、舗装表面における反射波強度は、舗装の材質及びその湿潤状態（天候）によって変化し、一般に水分量が多いと反射波強度が高くなり、水を含まない排水性舗装のように多孔質で空隙が多いと弱くなる。よって、取得した反射波データの強度をそのまま用いると、調査結果が舗装の湿潤状態、舗装の多孔性により変化してしまい、調査結果の客観性や汎用性が損なわれ、他の調査結果との対比も困難となる。よって、上述のように補正係数を乗じて反射波強度を補正するのが好ましい。
(Function and effect)
When electromagnetic waves are irradiated toward the pavement, the reflected wave intensity on the pavement surface varies depending on the material of the pavement and its wet condition (weather). Generally, when there is a large amount of water, the reflected wave intensity increases, and water does not contain water. It becomes weak when it is porous and has a lot of voids, such as pavement. Therefore, if the intensity of the acquired reflected wave data is used as it is, the survey results will change due to the wet state of the pavement and the porosity of the pavement, and the objectivity and versatility of the survey results will be impaired. Contrast is also difficult. Therefore, it is preferable to correct the reflected wave intensity by multiplying the correction coefficient as described above.
＜請求項３記載の発明＞
前記各反射波検出位置の反射波強度の違いが現された前記検出対象領域の平面可視化画像を作成し、この可視化画像に現れた、反射波強度が所定の強度しきい値以上となる領域の連続性の程度により、前記内部損傷箇所及び非内部損傷箇所を判別する、請求項１又は２記載の舗装の内部損傷箇所の非破壊調査方法。
<Invention of Claim 3 >
Create a planar visualization image of the detection target area showing the difference in reflected wave intensity at each of the reflected wave detection positions, and display the area of the reflected wave intensity that is greater than or equal to a predetermined intensity threshold that appears in the visualization image. The nondestructive investigation method for an internally damaged part of pavement according to claim 1 or 2 , wherein the internal damaged part and the non-internally damaged part are discriminated by a degree of continuity.
（作用効果）
このような平面可視化画像を作成することにより、内部損傷箇所及び非内部損傷箇所をより高精度に判別できるようになる。
(Function and effect)
By creating such a planar visualization image, it becomes possible to discriminate between the internal damage location and the non-internal damage location with higher accuracy.
＜請求項４記載の発明＞
前記舗装が、排水性舗装、オーバーレイ補修された舗装、又は表層打換えされた舗装である、請求項１〜３のいずれか１項に記載の舗装の内部損傷箇所の非破壊調査方法。
<Invention of Claim 4 >
The nondestructive investigation method of the internal damage location of the pavement according to any one of claims 1 to 3 , wherein the pavement is a drainage pavement, an overlay repaired pavement, or a pavement whose surface layer is replaced.
（作用効果）
排水性舗装は、表層が多孔質であるため、表面のひび割れが発見され難いという特徴がある。また、補修された舗装は、表面が綺麗でも内部損傷が増殖していることもある。よって、本発明はこれらの舗装の内部損傷箇所の調査に好適である。
(Function and effect)
Since drainage pavement has a porous surface layer, it has a feature that surface cracks are difficult to be found. Also, the repaired pavement may have increased internal damage even if the surface is clean. Therefore, this invention is suitable for the investigation of the internal damage location of these pavements.
以上のとおり、本発明によれば、舗装の内部損傷箇所を非破壊で迅速に定量調査できるようになる、等の利点がもたらされる。 As described above, according to the present invention, there are advantages such as the ability to quickly and quantitatively investigate the internal damage portion of the pavement in a non-destructive manner.
以下、本発明の一実施形態について添付図面を参照しながら詳説する。なお、「深さ方向」とは路面と直交する方向を意味する。 Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The “depth direction” means a direction orthogonal to the road surface.
＜計測＞
本発明は電磁波レーダーを用いて舗装の内部探査を行う。電磁波レーダーとしては、GSSI社（米国）製の各種電磁波レーダーシステム（例えばSIR3000等）、日本無線社製RCレーダー（例えばハンディサーチNJJ-95B等）、アイレック技建社製のコンクリート構造物の鉄筋探査装置（例えばライトエスパー）、コマツエンジニアリング社製のレーダ探査機（例えばアイアンシーカ）等、公知のものを特に限定無く用いることができるが、送受信センサを多数並設したレーダーシステムが高効率・高精度であるため好ましい。以下、具体例について説明する。
<Measurement>
The present invention performs an internal exploration of pavement using an electromagnetic wave radar. As electromagnetic wave radar, various electromagnetic wave radar systems (for example, SIR3000) manufactured by GSSI (USA), RC radar (for example, Handy Search NJJ-95B) manufactured by Japan Radio Co., Ltd. A known device such as a device (for example, Light Esper) or a radar probe (for example, an iron seeker) manufactured by Komatsu Engineering can be used without any particular limitation, but a radar system in which a large number of transmission / reception sensors are arranged in parallel is highly efficient and highly accurate. Therefore, it is preferable. Hereinafter, specific examples will be described.
図１は電磁波レーダーの概略図である。符号ａは電磁波の送受信アンテナおよび送受信回路を一体的にケースに組み込んだセンサａ、符号ｃはｎ個のセンサａを並列に連結してアレイ状としたアレイアンテナ、符号ｂはアレイアンテナｃを構成する各センサａに対して夫々スイッチングにより機能の切り替えを行い、個々に送受信および信号処理を行うようにするコントロールユニットをそれぞれ示している。なお、アレイアンテナｃとコントロールユニットｂとによりレーダーシステムｋを構成している。 FIG. 1 is a schematic diagram of an electromagnetic wave radar. Symbol a is a sensor a in which an electromagnetic wave transmission / reception antenna and a transmission / reception circuit are integrated in a case, symbol c is an array antenna in which n sensors a are connected in parallel, and symbol b is an array antenna c. A control unit is shown in which functions are switched by switching for each sensor a to perform transmission / reception and signal processing individually. The array antenna c and the control unit b constitute a radar system k.
レーダーシステムに用いられるセンサａとしては、ステップ波形によるインパルス発信を用いたものであって、周波数が０．５〜３ＧＨｚの中心帯域を持つものが好適であり、特に周波数を１ＧＨｚ以上として探査を行うと、波長が短いことから深さ方向の分解能が向上する。深さ方向の分解能は特に限定されないが、５ｃｍ未満であるのが好ましい。一方、電磁波は周波数が高くなるにつれて、物体中での減衰が激しくなるが、２ＧＨｚ以下で探査を行えば、ある程度の深度（４０ｃｍ以上）まで十分な探査を行うことができる。 As the sensor a used in the radar system, one using impulse transmission by a step waveform and having a center band with a frequency of 0.5 to 3 GHz is preferable, and the search is performed with a frequency of 1 GHz or more. And since the wavelength is short, the resolution in the depth direction is improved. The resolution in the depth direction is not particularly limited, but is preferably less than 5 cm. On the other hand, as the frequency of the electromagnetic wave increases, the attenuation in the object becomes severe. However, if the search is performed at 2 GHz or less, a sufficient search can be performed to a certain depth (40 cm or more).
コントロールユニットｂによりコントロールされた各センサａからは、舗装の表面Ｒから内部に向けて略垂直に電磁波が発振される。そして、舗装内からの反射波は各センサａに受信される。各センサａで受信された反射波は、コントロールユニットｂを介してアナログ信号からデジタル信号に変換されたデータとしてデータ処理装置に出力される。 From each sensor a controlled by the control unit b, electromagnetic waves are oscillated substantially vertically from the surface R of the pavement toward the inside. And the reflected wave from the inside of a pavement is received by each sensor a. The reflected wave received by each sensor a is output to the data processing device as data converted from an analog signal to a digital signal via the control unit b.
レーダーシステムｋは、より具体的には図２に示すように構成することができる。すなわち、レーダーシステムｋにおけるセンサａは送信部Ｔｘと受信部Ｒｘとにより構成され、ｎ個のセンサａへの給電は、例えばコントロールユニットｂに設けられた電源電池３１により供給され、また該電源電池はコントロールユニットｂ内の各回路に給電される。 More specifically, the radar system k can be configured as shown in FIG. That is, the sensor a in the radar system k is configured by the transmission unit Tx and the reception unit Rx, and power supply to the n sensors a is supplied by, for example, the power supply battery 31 provided in the control unit b. Is fed to each circuit in the control unit b.
ｎ個のセンサａの送信部への送信指令は、スイッチ切り替え制御回路３４が第１切り替えスイッチ３４ａを順次切り替えることにより、順次送信を行うようになっており、この切替のタイミングはタイミング源発振回路３３ｂで発生した数十ＭＨｚのクロックパルスにより行われ、例えばタイミングクロックパルスの周期毎に順次スイッチングされ、数μｓ後にはアレイアンテナのｎ個のセンサａを一巡する。 The transmission command to the transmission unit of the n sensors a is sequentially transmitted by the switch switching control circuit 34 sequentially switching the first changeover switch 34a, and the timing of this switching is the timing source oscillation circuit. This is performed by a clock pulse of several tens of MHz generated at 33b. For example, the switching is sequentially performed every period of the timing clock pulse, and after a few μs, the n sensors a of the array antenna are made a round.
各センサａの送信部Ｔｘで発信された電磁波は、測定対象物に対して反射と透過を繰り返し、その内部状況を反射信号としてセンサａの受信部Ｒｘで受信する。受信された反射信号は、同期信号発生回路３３からの同期信号に従ってサンプリングされ、低周波の受信信号１〜ｎに変換されて各センサから出力される。各センサから出力された受信信号は、スイッチ切り替え回路３４にて、Ａ／Ｄ変換回路３５およびバッファ３６により信号の処理が行われ、第２切り替えスイッチ３４ｂの切り替えにより順次データ処理装置へ出力される。 The electromagnetic wave transmitted by the transmission unit Tx of each sensor a repeats reflection and transmission with respect to the measurement object, and receives the internal state as a reflection signal by the reception unit Rx of the sensor a. The received reflected signal is sampled according to the synchronizing signal from the synchronizing signal generation circuit 33, converted into low frequency received signals 1 to n, and output from each sensor. The received signals output from the sensors are processed in the switch switching circuit 34 by the A / D conversion circuit 35 and the buffer 36, and are sequentially output to the data processing device by switching the second selector switch 34b. .
図３の（ａ）は、レーダーシステムｋが図１に示す単配列状態を示しており、副走査方向におけるセンサａの間隔をｄとすると、この単配列状態の分解能はｄとなる。これに対し、図３の（ｂ）に示すように、ｎ列の単配列のアレイアンテナｃ１を千鳥状にｍ行配列することにより、このアレイアンテナｃ２は、ｍ倍の分解能を得ることができ、これにより水平解像度が決定される。そして、単配列時におけるアレイアンテナｃ１の分解能ｄに対し、ｍ行配列するアレイアンテナｃ２は、ｄ／ｍの分解能となる。また、図４に示すように、センサａをｍ行×ｎ列に配列したアレイアンテナｃ３としても良い。この構成では、アレイアンテナｃ３を移動させることなく一度にｍ行×ｎ列の範囲で探査を行える。 FIG. 3A shows the single array state shown in FIG. 1 when the radar system k is shown in FIG. 1. If the interval of the sensors a in the sub-scanning direction is d, the resolution of this single array state is d. On the other hand, as shown in FIG. 3B, the array antenna c2 can obtain m times the resolution by arranging the array antenna c1 of the single array of n columns in a staggered pattern of m rows. This determines the horizontal resolution. The array antenna c2 arranged in m rows has a resolution of d / m with respect to the resolution d of the array antenna c1 in the single array. Moreover, as shown in FIG. 4, it is good also as the array antenna c3 which arranged the sensor a in m row xn column. In this configuration, the search can be performed in a range of m rows × n columns at a time without moving the array antenna c3.
探査に際しては、作業員がアンテナを逐次移動させながら測定を行っても良いが、図５に示すように、レーダーシステムｋを搭載した自動車等の探査車１０で舗装路面Ｒを走行しながら、舗装路面Ｒにおける検出対象領域の全体にわたり、路面Ｒに沿う方向に所定の間隔を空けて探査を行うのが望ましい。図５に示す探査車１０は、レーダーシステムｋの他に、光学式距離計（回転式距離計でも良い）１１、路面状況を撮像するためのカメラ１２、ＧＰＳ装置１３を搭載しており、これらの出力信号がデータ処理装置１４に入力されるように構成されている。データ収録装置１４としては、汎用のコンピュータを用いることができる。図示例では、データ処理装置１４等の機器を牽引する構造となっているため、データ処理装置１４等の機器を制御するための制御装置１５を車両に搭載している。 During the exploration, the operator may perform the measurement while sequentially moving the antenna. However, as shown in FIG. 5, the paving is performed while traveling on the paved road surface R with the exploration vehicle 10 such as an automobile equipped with the radar system k. It is desirable that the entire search target area on the road surface R is searched with a predetermined interval in the direction along the road surface R. In addition to the radar system k, the exploration vehicle 10 shown in FIG. 5 is equipped with an optical distance meter (or a rotary distance meter) 11, a camera 12 for imaging road surface conditions, and a GPS device 13. Is output to the data processing device 14. A general-purpose computer can be used as the data recording device 14. In the illustrated example, a device such as the data processing device 14 is pulled, and thus a control device 15 for controlling the device such as the data processing device 14 is mounted on the vehicle.
レーダーシステムｋにおけるセンサａの配列方向を副走査方向とし、副走査方向および電磁波の発信方向に対して直交する方向を主走査方向とすると、レーダーシステムｋの主走査方向は探査車１０の走行方向となっており、走行に伴う移動距離は距離計１１からデータ処理装置１４に対して入力されるようになっている。 If the arrangement direction of the sensors a in the radar system k is the sub-scanning direction, and the direction perpendicular to the sub-scanning direction and the electromagnetic wave transmission direction is the main scanning direction, the main scanning direction of the radar system k is the traveling direction of the exploration vehicle 10. Thus, the travel distance associated with travel is input from the distance meter 11 to the data processing device 14.
図６は、レーダーシステムｋを主走査方向に移動させて得られた情報を処理するプロセスを示している。レーダーシステムｋは検査対象である舗装路面Ｒ上に支持され、主走査方向に沿って移動される。その際、コントロールユニットｂは、例えばｎ個のセンサａ（１，２，・・・・ｎ）を順に駆動し、副走査方向の各位置における反射波データが主走査方向について時々刻々と出力する。つまり、図７に示すように、反射波データ（強度（振幅）及び深度（時間））４２は、主走査方向に所定の反射波検出間隔（移動方向の位置間隔）で、且つ副走査方向に所定の反射波検出間隔（センサ配列間隔）で定まる各検出位置４１で取得される。これらの検出間隔は適宜定めることができるが、１０ｃｍ未満であることが望ましい。 FIG. 6 shows a process for processing information obtained by moving the radar system k in the main scanning direction. The radar system k is supported on the paved road surface R to be inspected and moved along the main scanning direction. At that time, the control unit b drives, for example, n sensors a (1, 2,... N) in order, and the reflected wave data at each position in the sub-scanning direction is output momentarily in the main scanning direction. . That is, as shown in FIG. 7, the reflected wave data (intensity (amplitude) and depth (time)) 42 has a predetermined reflected wave detection interval (position interval in the moving direction) in the main scanning direction and in the sub-scanning direction. It is acquired at each detection position 41 determined by a predetermined reflected wave detection interval (sensor array interval). These detection intervals can be determined as appropriate, but are preferably less than 10 cm.
取得される各検出位置４０の反射波データ５０は、各検出位置４０の位置情報と関連付けて、データ処理装置１４に内蔵又は接続された図示しない記憶装置に記録される。この際、各検出位置４０の位置情報の生データは、主走査方向移動距離及び副走査方向のセンサ配列間隔であるが、必要に応じて三次元座標に変換し、生データと併せて記録することができ、また、反射波データ５０は波形データであるが、必要に応じて後述する総エネルギーや反射波強度の最大値を求めて、波形データとともに記録することができる。 The acquired reflected wave data 50 at each detection position 40 is recorded in a storage device (not shown) built in or connected to the data processing device 14 in association with the position information of each detection position 40. At this time, the raw data of the position information of each detection position 40 is the movement distance in the main scanning direction and the sensor array interval in the sub-scanning direction, but is converted into three-dimensional coordinates as necessary and recorded together with the raw data. Although the reflected wave data 50 is waveform data, the maximum value of total energy and reflected wave intensity, which will be described later, can be obtained and recorded together with the waveform data as necessary.
＜分析＞
上述の計測により舗装路面Ｒにおける検出対象領域の全体にわたり反射波データ５０を取得したならば、次いで取得データ５０の分析を行い、検出対象領域に占める内部損傷６１を有する箇所（内部損傷箇所）の割合を定量化する。この定量化の手順の一例が図８に示されている。まず、好適には取得した反射波データ５０の強度補正を行う。図９に示すように、電磁波の反射波５０のうち舗装表面Ｒからの反射波強度５１は、舗装の材質及びその湿潤状態（天候）によって変化し、一般に水分量が多いと反射波強度が高くなり、水を含まない排水性舗装のように多孔質で空隙が多いと弱くなる。よって、この影響を排除するため、例えば図９に示すように補正係数を乗じて反射波データ５０の強度を深さ方向全体にわたり補正する。なお、図９中の符号６５は路盤層を、また符号６０は路盤６５上を被覆する被覆層（アスファルト舗装における表層及び基層。ただし、上層路盤がアスファルト安定処理されたアスファルト混合物層の場合のみ、表層から上層路盤までを被覆層という）を示している。補正係数は、例えば乾燥状態の密粒度アスファルト表面における反射波強度を予め又は後に計測して標準データとし、この標準データと本計測における舗装表面Ｒにおける反射波強度との比をとることにより設定することができ、例えば下表のように設定することができる。なお、雨の日であって路面表面に滞水が見られる場合は、補正できるレベルに無いため、調査を避けるのが望ましい。
<Analysis>
If the reflected wave data 50 is acquired over the entire detection target area on the pavement road surface R by the above-described measurement, then the acquired data 50 is analyzed, and the location (internal damage location) of the internal damage 61 in the detection target area is analyzed. Quantify the percentage. An example of this quantification procedure is shown in FIG. First, the intensity of the acquired reflected wave data 50 is preferably corrected. As shown in FIG. 9, the reflected wave intensity 51 from the pavement surface R of the reflected wave 50 of the electromagnetic wave varies depending on the material of the pavement and its wet state (weather), and generally the reflected wave intensity is high when the amount of water is large. It becomes weak when it is porous and has many voids, such as drainage pavement that does not contain water. Therefore, in order to eliminate this influence, for example, as shown in FIG. 9, the intensity of the reflected wave data 50 is corrected over the entire depth direction by multiplying the correction coefficient. In addition, the code | symbol 65 in FIG. 9 is a roadbed layer, and the code | symbol 60 is a coating layer (surface layer and base layer in asphalt pavement covering the road bed 65. However, only when the upper layer roadbed is an asphalt-stabilized asphalt mixture layer, The surface layer to the upper layer roadbed are called coating layers). The correction coefficient is set, for example, by measuring the reflected wave intensity on a dry dense asphalt surface in advance or later as standard data and taking the ratio of the standard data and the reflected wave intensity on the pavement surface R in this measurement. For example, it can be set as shown in the following table. If it is rainy and there is water on the road surface, it is not possible to correct it and it is desirable to avoid investigation.
次に、舗装表面Ｒより下側における反射波５３の総エネルギーを各反射波検出位置４０について算出し、この総エネルギーが所定のエネルギーしきい値以下となる反射波検出位置４０を内部損傷箇所と判別する。すなわち、通常の場合、図１０（ａ）に示すように、反射波は舗装表面Ｒで最も強く且つ一定のピーク５１が現れ、路盤被覆層６０（アスファルト舗装ではアスファルト層又はコンクリート舗装ではコンクリート層）の下面（路盤層との境界）でも比較的強いピーク５２が現れる。しかし、被覆層６０内に粒状に崩れた損傷部分が存在していると、その損傷部分において入射波及び反射波が散乱してしまうため、図１０（ｂ）に示すように、舗装表面Ｒより下側における反射波５３にピークが殆ど現れなくなる。そこで、舗装表面Ｒにおける反射波ピーク５１を基準としてそれよりも下側の反射波５３の総エネルギーを算出し、この総エネルギーが所定のエネルギーしきい値以下であるか否かを基準に区別すれば、被覆層６０内に粒状に崩れた損傷部分が存在しているか否かを検出することができる。このエネルギーしきい値は適宜定めることができるが、通常の場合は舗装表面Ｒの反射波ピーク５１の強度に対して（以下、単に対舗装表面という）５〜２０％、特に５〜１５％とするのが好ましい。ここで、エネルギーしきい値を定める基準となる舗装表面Ｒの反射波ピーク５１の強度は、各検出位置毎に求めたり、任意の検出位置における値を代表的に用いたりしても良いが、複数の検出位置（例えば、一度に計測が行われた道路区間若しくはその一部の区間）の平均値を用いるのがより好ましい。 Next, the total energy of the reflected wave 53 below the pavement surface R is calculated for each reflected wave detection position 40, and the reflected wave detection position 40 at which this total energy is equal to or less than a predetermined energy threshold is determined as an internal damage location. Determine. That is, in the normal case, as shown in FIG. 10A, the reflected wave has the strongest and constant peak 51 on the pavement surface R, and the roadbed covering layer 60 (asphalt pavement for asphalt pavement or concrete layer for concrete pavement). A relatively strong peak 52 also appears on the lower surface (boundary with the roadbed layer). However, if there is a damaged portion broken into a granular shape in the coating layer 60, the incident wave and the reflected wave are scattered in the damaged portion, and therefore, as shown in FIG. A peak hardly appears in the reflected wave 53 on the lower side. Therefore, the total energy of the reflected wave 53 below is calculated on the basis of the reflected wave peak 51 on the pavement surface R, and a distinction is made based on whether or not the total energy is below a predetermined energy threshold value. For example, it is possible to detect whether or not there is a damaged portion broken into particles in the coating layer 60. This energy threshold value can be determined as appropriate, but in the normal case, it is 5 to 20%, particularly 5 to 15%, with respect to the intensity of the reflected wave peak 51 of the pavement surface R (hereinafter simply referred to as the pavement surface). It is preferable to do this. Here, the intensity of the reflected wave peak 51 of the pavement surface R that serves as a reference for determining the energy threshold value may be obtained for each detection position, or a value at an arbitrary detection position may be representatively used. It is more preferable to use an average value of a plurality of detection positions (for example, a road section measured at a time or a part of the section).
なお、内部損傷は、舗装表面Ｒに沿う方向にある程度の広がりを有している場合が多く、通常レベルのレーダーの分解能を有していれば、局所的（例えば一つの検出位置だけ）に総エネルギーが低くなるようなことは殆ど無い。よって、局所的に総エネルギーが低くなった場合は、誤検出の可能性が高いため排除するのが望ましい。具体的には、総エネルギーが所定のエネルギーしきい値以下である検出位置４０の数や面積を算出し、所定しきい値以下である場合は誤検出として内部損傷が無かったものとしても良いが、このような微妙な判断は自動化するよりも作業員が行った方が良いため、各反射波検出位置４０の総エネルギー値の違いが濃淡、色分け、これらの組み合わせ等で現された検出対象領域の平面可視化画像を作成し、作業員がこの画像に基づいて、総エネルギーが所定のエネルギーしきい値以下の部分の連続性を見て、連続性が十分にあると認められる場合に内部損傷があり、連続性が無いと認められる場合に内部損傷が無いものと識別するのが望ましい。この場合に作成する平面可視化画像としては、総エネルギーの違いが一様に現された画像よりも、総エネルギーが所定の強度しきい値以下である箇所を他の箇所と異なる色で表示すること（又は線で囲む等でも良い）により強調表示した画像が好ましい。この画像の表示については、リアルタイムに表示させてもよく、またデータの取得後に表示領域の指定により表示させるようにしてもよい。これらの画像処理については、後述の反射強度の場合と基本は同様であるため、反射強度の画像例を参照されたい。 In many cases, the internal damage has a certain extent in the direction along the pavement surface R. If the radar has a normal level of resolution, the damage is locally (for example, only one detection position). There is almost no reduction in energy. Therefore, if the total energy is locally low, it is desirable to eliminate it because the possibility of erroneous detection is high. Specifically, the number and area of the detection positions 40 where the total energy is equal to or lower than a predetermined energy threshold value are calculated. If the total energy is equal to or lower than the predetermined threshold value, it may be assumed that there is no internal damage as a false detection. Such subtle judgment is better performed by the worker rather than automating, so that the difference in the total energy value of each reflected wave detection position 40 is indicated by the shade, color classification, combination of these, etc. If the worker creates a flat visualization image of the image and sees the continuity of the part where the total energy is below the predetermined energy threshold based on this image, the internal damage is found to be sufficient. It is desirable to identify that there is no internal damage when it is recognized that there is no continuity. As a planar visualization image created in this case, the part where the total energy is equal to or less than the predetermined intensity threshold is displayed in a different color from the other parts, rather than an image where the difference in total energy appears uniformly. An image highlighted in (or by surrounding with a line) is preferable. The image may be displayed in real time, or may be displayed by specifying a display area after data acquisition. Since these image processes are basically the same as in the case of the reflection intensity described later, refer to the image example of the reflection intensity.
一方、総エネルギーが所定のエネルギーしきい値を超える反射波検出位置４０については、図１１に示すように、各反射波検出位置４０の反射波データ５０における舗装表面の反射波ピーク５１と路盤被覆層下面の反射波ピーク５２との間の部分５４（つまり路盤被覆層の内部損傷によりピークが発生する可能性がある部分）から、反射波強度の最大値５５を当該反射波検出位置４０の反射波強度の代表値としてそれぞれ取得し、図１２に示すように、この代表値５５が所定の強度しきい値以上となる反射波検出位置４０を内部損傷箇所とし、且つ反射波強度の代表値５５が所定の強度しきい値未満となる反射波検出位置を非内部損傷箇所として判別する。また、基準となる強度しきい値は適宜定めることができるが、通常の場合は対舗装表面で５〜１５％とするのが好ましい。ここで、強度しきい値を定める基準となる舗装表面Ｒの反射波ピーク５１の強度は、エネルギーしきい値の場合と同様であり、各検出位置毎に求めたり、任意の検出位置における値を代表的に用いたりしても良いが、複数の検出位置（例えば、一度に計測が行われた道路区間若しくはその一部の区間）の平均値を用いるのがより好ましい。 On the other hand, with respect to the reflected wave detection position 40 where the total energy exceeds a predetermined energy threshold value, as shown in FIG. 11, the reflected wave peak 51 and the roadbed cover on the pavement surface in the reflected wave data 50 at each reflected wave detection position 40. The maximum value 55 of the reflected wave intensity is reflected from the reflected wave detection position 40 from a portion 54 between the reflected wave peak 52 on the lower surface of the layer (that is, a portion where a peak may occur due to internal damage of the roadbed covering layer). As a representative value of the wave intensity, as shown in FIG. 12, the reflected wave detection position 40 where the representative value 55 is equal to or greater than a predetermined intensity threshold is used as an internal damage location, and the representative value 55 of the reflected wave intensity is obtained. Is determined as a non-internal damage location. Moreover, although the intensity | strength threshold value used as a reference | standard can be determined suitably, it is preferable to set it as 5 to 15% with respect to a pavement surface in the normal case. Here, the intensity of the reflected wave peak 51 of the pavement surface R, which serves as a reference for determining the intensity threshold, is the same as in the case of the energy threshold, and can be obtained for each detection position, Although it may be representatively used, it is more preferable to use an average value of a plurality of detection positions (for example, a road section in which measurement is performed at one time or a part of the section).
前述のとおり、内部損傷は、路面に沿う方向にある程度の広がりを有している場合が多いため、通常レベルのレーダーの分解能を有していれば、局所的（例えば一つの検出位置だけ）に反射波強度が高くなるようなことは殆ど無い。よって、前述の総エネルギー値の場合と同様に、局所的に反射波強度が高くなった場合は、誤検出の可能性が高いため排除するのが望ましい。具体的には、反射波強度が所定の強度しきい値以上である検出位置４０の数や面積を算出し、所定しきい値以下である場合は誤検出として内部損傷が無かったものとしても良いが、このような微妙な判断は自動化するよりも作業員が行った方が良いため、図１３に示すように各反射波検出位置４０の反射波強度の違いが濃淡、色分け、これらの組み合わせ等で現された検出対象領域の平面可視化画像７０を作成し、作業員がこの画像７０に基づいて、反射波強度が所定の強度しきい値以上の部分７１（図示例では色の濃い部分）の連続性を見て、連続性が十分にあると認められる場合に内部損傷があり、連続性が無いと認められる場合に内部損傷が無いものと識別するのが望ましい。この場合に作成する平面可視化画像としては、図１３に示すように、反射波強度の違いが濃淡で一様に現された画像７０よりも、図１４に示すように反射波強度が所定の強度しきい値以上である箇所８１が他の箇所と極端に異なる色で表示すること（又は線で囲む等でも良い）により強調表示された画像８０が好ましい。なお、図１４の（ａ）図及び（ｂ）図は、それぞれ図１３の（ａ）図及び（ｂ）図と同じ部分を強調表示したものである。この画像の表示については、リアルタイムに表示させてもよく、またデータの取得後に表示領域の指定により表示させるようにしてもよい。 As described above, internal damage often has a certain extent in the direction along the road surface. Therefore, if the radar has a normal level of resolution, it is locally (for example, only one detection position). The reflected wave intensity is hardly increased. Therefore, as in the case of the total energy value described above, if the reflected wave intensity is locally high, it is desirable to eliminate it because the possibility of erroneous detection is high. Specifically, the number and area of the detection positions 40 where the reflected wave intensity is equal to or greater than a predetermined intensity threshold value may be calculated. However, since it is better for the operator to make such a delicate determination than to automate, the difference in the reflected wave intensity at each reflected wave detection position 40 is different from each other as shown in FIG. A plane visualization image 70 of the detection target area shown in FIG. 6 is created. Based on this image 70, an operator creates a portion 71 (a dark-colored portion in the illustrated example) whose reflected wave intensity is equal to or greater than a predetermined intensity threshold value. From the viewpoint of continuity, it is desirable to identify that there is internal damage when it is recognized that there is sufficient continuity, and that there is no internal damage when it is recognized that there is no continuity. As shown in FIG. 13, the planar visualized image created in this case has a reflected wave intensity of a predetermined intensity as shown in FIG. 14 rather than an image 70 in which the difference in reflected wave intensity is uniformly expressed in shades. An image 80 that is highlighted by displaying a location 81 that is equal to or greater than the threshold in a color extremely different from other locations (or may be surrounded by a line) is preferable. 14A and 14B show the same portions as those in FIGS. 13A and 13B, respectively. The image may be displayed in real time, or may be displayed by specifying a display area after data acquisition.
これらの結果が得られたならば、検出対象領域に占める内部損傷箇所７１，８１の割合、つまり内部損傷率（内部ひび割れ率）を求める。この算出方法は適宜定めることができるが、例えば、我が国の道路管理において標準的となっているひび割れ率（表面に現れたひび割れ等の表面露見損傷に基づくもの）を応用することができる。図１５は、この算出方法の概要を示しており、この方法は、検出対象領域を０．５ｍ×０．５ｍ程度の矩形の単位領域（以下、グリッドという）に分割し、グリッド内の損傷の種類、数、面積に応じて定まる所定の式により各グリッドの損傷面積を算出し、これを全グリッドの面積で除算してひび割れ率を算出するというものである。そして、このひび割れ率は、前述のＭＣＩ値又はＰＳＩ値の算出式におけるＣ値（ひび割れ率）としてそのまま代入することができ、これにより求まるＭＣＩ値又はＰＳＩ値は従来のものと同様に舗装の評価に用いることができる。 If these results are obtained, the ratio of the internal damage locations 71 and 81 in the detection target area, that is, the internal damage rate (internal crack rate) is obtained. Although this calculation method can be determined as appropriate, for example, a crack rate (based on surface exposure damage such as a crack appearing on the surface) that is standard in road management in Japan can be applied. FIG. 15 shows an outline of this calculation method. This method divides the detection target area into rectangular unit areas (hereinafter referred to as grids) of about 0.5 m × 0.5 m, and damages in the grid are calculated. The damage area of each grid is calculated by a predetermined formula determined according to the type, number, and area, and the crack ratio is calculated by dividing this by the area of all grids. The crack rate can be directly substituted as the C value (crack rate) in the above-described calculation formula of the MCI value or PSI value, and the MCI value or PSI value obtained by this can be evaluated in the same way as the conventional one. Can be used.
ひび割れ率が高い場合等、必要に応じて、次のような詳細な分析を更に行い、内部損傷の位置や種類を特定することができる。すなわち、内部損傷の位置は、舗装上面から下面まで深さ方向に所定の間隔（分解能以下）で、各深さにおける各反射波検出位置４０の反射波強度をそれぞれ取得し、所定の強度しきい値以上の反射波検出位置４０を当該深さにおける内部損傷箇所として、平面位置及び深さ方向位置を求めることができる。また、舗装上面Ｒから深さ方向に所定の間隔（分解能以下）で、各深さにおける各反射波検出位置４０の反射波強度の違いが濃淡、色分け、これらの組み合わせ等で現された検出対象領域の平面可視化画像をそれぞれ作成し、各深さの平面可視化画像に基づいて内部損傷箇所の平面位置及び深さ方向位置を求めることもできる。 If the crack rate is high, the following detailed analysis can be further performed as necessary to identify the position and type of internal damage. That is, the position of the internal damage is obtained by obtaining the reflected wave intensity at each reflected wave detection position 40 at each depth at a predetermined interval (below the resolution) in the depth direction from the upper surface to the lower surface of the pavement, and the predetermined intensity threshold. The plane position and the position in the depth direction can be obtained by setting the reflected wave detection position 40 that is equal to or greater than the value as an internal damage location at the depth. In addition, a detection target in which a difference in reflected wave intensity at each reflected wave detection position 40 at each depth is expressed by shading, color classification, a combination thereof, etc. at a predetermined interval (below resolution) in the depth direction from the pavement upper surface R. It is also possible to create a planar visualization image of each region and obtain the planar position and depth direction position of the internal damage location based on the planar visualization image of each depth.
また、内部損傷の種類は、下表に示すように、内部損傷箇所（内部損傷を有する検出位置４０）の反射波強度、周波数分析、及び平面形状を単独又は適宜組み合わせることにより識別することができる。 Also, as shown in the table below, the type of internal damage can be identified by combining the reflected wave intensity, frequency analysis, and planar shape of the internal damage location (detection position 40 having internal damage) alone or appropriately. .
もちろん、この詳細分析とともに又はこれに代えて、従来の「破損原因の調査」を行っても良い。 Of course, a conventional “investigation of damage cause” may be performed together with or instead of this detailed analysis.
＜その他＞
（イ）評価対象の舗装は、特に限定されないが、路盤上にアスファルト合材からなる路盤被覆層（基層・表層）が設けられたアスファルト舗装、路盤被覆層がセメントコンクリートからなるコンクリート舗装が好適であり、特に排水性舗装、オーバーレイ補修された舗装、表層打換えされた舗装が好適である。
（ロ）内部損傷とは、内部にのみ存在し、表面に露出していないひび割れ、層間剥離、滞水部分の他、表面に露出しているが内部まで延在しているひび割れや、ポットホール、パッチング、局部打ち換え部分等を含む。
<Others>
(B) The pavement to be evaluated is not particularly limited, but asphalt pavement in which a roadbed covering layer (base layer / surface layer) made of asphalt mixture is provided on the roadbed, concrete pavement in which the roadbed covering layer is made of cement concrete is suitable. In particular, drainage pavement, pavement with overlay repair, and pavement replaced with surface layer are suitable.
( B ) Internal damage refers to cracks that are present only in the interior and are not exposed on the surface, delamination, and stagnant parts, cracks that are exposed on the surface but extend to the interior, and potholes. , Patching, local replacement part, etc.
本発明は、道路の維持・管理等に際して、アスファルト舗装等の舗装におけるひび割れ等の内部損傷箇所を、非破壊で定量調査するために利用できるものである。 INDUSTRIAL APPLICABILITY The present invention can be used for non-destructive quantitative investigation of internal damage sites such as cracks in pavements such as asphalt pavements during road maintenance and management.
ｋ…電磁波レーダーシステム、ａ…センサ、１０…探査車、１１…光学式距離計、１２…カメラ、１３…ＧＰＳ装置、１４…データ処理装置、１５…制御装置、Ｒ…舗装表面（路面）、４０…反射波検出位置、５０…反射波、５１…舗装表面におけるピーク、５２…被覆層底面におけるピーク、５２…反射波強度の代表値、６０…被覆層、６１…内部損傷、６５…路盤、７０…反射波強度の平面可視化画像、７１…内部損傷箇所、８０…強調表示された反射波強度の平面可視化画像、８１…内部損傷箇所。 k ... electromagnetic wave radar system, a ... sensor, 10 ... exploration vehicle, 11 ... optical distance meter, 12 ... camera, 13 ... GPS device, 14 ... data processing device, 15 ... control device, R ... pavement surface (road surface), 40 ... reflected wave detection position, 50 ... reflected wave, 51 ... peak on pavement surface, 52 ... peak on bottom surface of coating layer, 52 ... representative value of reflected wave intensity, 60 ... coating layer, 61 ... internal damage, 65 ... roadbed, 70: Planar visualization image of reflected wave intensity, 71: Internal damage location, 80 ... Planar visualization image of reflected wave intensity highlighted, 81: Internal damage location.
Claims (4)
電磁波レーダーを用い、舗装路面における検出対象領域の全体にわたり、路面に沿う方向に所定の間隔を空けて、舗装上から舗装内へ電磁波を深さ方向に入射させるとともにその反射波を舗装上で検出することにより、各反射波検出位置における反射波データを取得し、
この取得した反射波データに基づき、前記各反射波検出位置の反射波データにおける舗装表面の反射波ピークと路盤被覆層下面の反射波ピークとの間の部分から、反射波強度の最大値を当該反射波検出位置の反射波強度の代表値としてそれぞれ取得するとともに、
前記取得した反射波データに基づき、舗装表面における反射波ピークより下側における反射波の総エネルギーを前記各反射波検出位置について算出し、
この総エネルギーが所定のエネルギーしきい値以下となる反射波検出位置を内部損傷箇所とするとともに、
総エネルギーが所定のエネルギーしきい値を超える反射波検出位置であって、且つ前記反射波強度の代表値が所定の強度しきい値以上となる反射波検出位置を内部損傷箇所とし、
総エネルギーが所定のエネルギーしきい値を超える反射波検出位置であって、且つ反射波強度の代表値が所定の強度しきい値未満となる反射波検出位置を非内部損傷箇所として、
前記検出対象領域に占める内部損傷箇所の割合を定量化する、
ことを特徴とする舗装の内部損傷箇所の非破壊調査方法。 A non-destructive method for quantitatively investigating the internal damage of pavements,
Using an electromagnetic wave radar, electromagnetic waves are incident in the depth direction from the pavement into the pavement at a predetermined interval in the direction along the road surface over the entire detection target area on the pavement surface, and the reflected wave is detected on the pavement. By obtaining reflected wave data at each reflected wave detection position,
Based on the acquired reflected wave data, the maximum value of the reflected wave intensity is calculated from the portion between the reflected wave peak on the pavement surface and the reflected wave peak on the lower surface of the roadbed covering layer in the reflected wave data at each reflected wave detection position. While obtaining each as a representative value of the reflected wave intensity at the reflected wave detection position ,
Based on the acquired reflected wave data, the total energy of the reflected wave below the reflected wave peak on the pavement surface is calculated for each reflected wave detection position,
While the reflected wave detection position where this total energy is below a predetermined energy threshold is an internal damage location,
The reflected wave detection position where the total energy exceeds a predetermined energy threshold, and the reflected wave detection position where the representative value of the reflected wave intensity is equal to or greater than the predetermined intensity threshold is an internal damage location,
The reflected wave detection position where the total energy exceeds the predetermined energy threshold and the reflected wave detection position at which the representative value of the reflected wave intensity is less than the predetermined intensity threshold is defined as a non-internal damage location.
Quantifying the proportion of internal damage occupying the detection target area,
A non-destructive investigation method for internally damaged parts of pavements characterized by
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