JP2014106146A - Drain deterioration determination method - Google Patents
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本発明は水道管などの配水管の更新時期を判断するために用いられる配水管の老朽化判定方法に関するものである。 The present invention relates to a method for determining aging of a water pipe used for judging the renewal time of a water pipe such as a water pipe.
国民生活を維持するライフラインとして全国的に水道管が埋設されているが、経年的使用により水道管内部に腐食や劣化が起こり、このため、既設の水道管については順次更新する配管工事を行う必要がある。ここで、水道管の腐食や劣化が埋設経過年数に比例するものであれば、経過年数に従って順番に更新すれば良いが、腐食や劣化の度合いは水道管の材質、水道管の埋設環境、水道管に流れる水の水質等によって異なるし、他方、埋設経過年数に順次て行う方法を採用するにしても水道管の配管工事記録が適切に管理されていなときは、この方法も採用することができない。 Although water pipes are buried nationwide as a lifeline to maintain the people's lives, corrosion and deterioration occur in the water pipes due to aging, and therefore, the existing water pipes will be renewed sequentially. There is a need. Here, if the corrosion and deterioration of the water pipe is proportional to the age of burial, it may be updated in order according to the number of years of aging, but the degree of corrosion and deterioration depends on the material of the water pipe, the burial environment of the water pipe, Depending on the quality of the water flowing in the pipe, etc., on the other hand, even if the method of sequentially performing the embedment age is adopted, this method may also be adopted if the plumbing records of the water pipe are not properly managed. Can not.
そこで、従来、埋設された水道管の外面の腐食深さを測定して老朽化を判定する方法(特許文献1)、或いは、水道管の流れを遮断して遮断に伴う衝撃波を測定して水道管の劣化を判定する方法(特許文献2)などが提案されている。 Therefore, conventionally, a method of determining the aging by measuring the corrosion depth of the outer surface of the buried water pipe (Patent Document 1), or measuring the shock wave accompanying the interruption by blocking the flow of the water pipe and measuring the water A method for determining deterioration of a pipe (Patent Document 2) has been proposed.
しかしながら、従来の老朽化判定方法のうち前者の判定方法では、地中に埋設された水道管の外面腐食を検査するため、水道管の少なくとも一部を掘り返す必要があり、コストが割高な判定方法となっていたし、他方、後者の判定方法においても衝撃波を発生させるため、衝撃波発生装置が必要となり、これまた、判定構造がコストが極めて高くなっていた。また、前者の判定方法において水道管の一部を検査しただけでは水道管全体の老朽化状況を把握できないという問題点を有していた。 However, in the former judgment method among the conventional aging judgment methods, it is necessary to dug at least part of the water pipe in order to inspect the external corrosion of the water pipe buried in the ground, and the judgment method is expensive. On the other hand, in the latter determination method, a shock wave generator is required to generate a shock wave, and the determination structure is extremely expensive. In addition, there was a problem that the aging status of the entire water pipe cannot be grasped only by inspecting a part of the water pipe in the former determination method.
本発明の目的は、前記従来の問題点に鑑み、水道管等の配水管全体の劣化状況を正確に判断でき、コストも割安になる配水管の老朽化判定方法を提供することにある。 An object of the present invention is to provide a method for determining the deterioration of a distribution pipe that can accurately determine the deterioration status of the entire distribution pipe, such as a water pipe, in view of the above-described conventional problems, and that also reduces the cost.
前記課題を解決するため、本発明に配水管の老朽化判定方法は、流れ方向に離隔した異なる箇所から配水管の水試料を採取する採水工程と、採取した水試料に含まれる懸濁態元素を分析し懸濁態元素の濃度を測定する濃度測定工程と、異なる水試料の懸濁態元素濃度に基づき懸濁態元素濃度の変化量を計測する変化量計測工程と、計測された懸濁態元素濃度の変化量に基づき水質解析を行う水質解析工程とを有している。 In order to solve the above-mentioned problem, the method for determining aging of a water pipe according to the present invention includes a water sampling step of collecting a water sample of the water pipe from different locations separated in the flow direction, and a suspended state included in the collected water sample. A concentration measurement process for analyzing elements and measuring the concentration of suspended elements; a change measurement process for measuring changes in suspended element concentrations based on suspended element concentrations of different water samples; And a water quality analysis process for performing water quality analysis based on the amount of change in turbid element concentration.
本発明によれば、配水管、例えば水道管内に流れる水試料を検査対象としているため、水道管に連結している消火栓や空気弁から採取できるため、試料の入手が簡単である。また、水試料が水道管の流れ方向に離隔した箇所から採取し、かつ、水試料の懸濁態元素濃度の変化量に基づき水質解析を行うため、水道管の上流から下流に亘る水道管全体の老朽化を判断することができる。 According to the present invention, since a water sample flowing in a water pipe, for example, a water pipe, is an object to be tested, it can be collected from a fire hydrant or an air valve connected to the water pipe, so that the sample can be easily obtained. In addition, since the water sample is collected from a location separated in the flow direction of the water pipe and the water quality analysis is performed based on the amount of change in the suspended element concentration of the water sample, the entire water pipe extending from the upstream to the downstream of the water pipe Can be judged as aging.
なお、水質解析として多変量解析(主成分分析)を採用するようにしてもよく、この場合には、第1主成分は腐食生成物に起因する懸濁態元素(Fe、Al又はMnの少なくとも一つ)であり、第2主成分はモルタルライニング劣化に起因する懸濁態元素(Ca)となっている。 Note that multivariate analysis (principal component analysis) may be adopted as the water quality analysis. In this case, the first main component is at least a suspended element (Fe, Al, or Mn) caused by the corrosion product. 1), and the second main component is a suspended element (Ca) due to deterioration of the mortar lining.
本発明によれば、配水管の老朽化判定において、コストが割安となり、かつ、水道管全体の劣化状況を正確に判断することができる。 According to the present invention, it is possible to accurately determine the deterioration state of the entire water pipe, and the cost is reduced in the determination of aging of the water pipe.
図1乃至図5は本発明に係る配水管(水道管)の老朽化判定方法の一実施形態を示すものである。 1 to 5 show an embodiment of a method for determining aging of a water pipe (water pipe) according to the present invention.
この老朽化判定方法の工程は図1に示すとおりである。 The process of this aging determination method is as shown in FIG.
まず、水道管の流れ方向の2地点から水試料を採取する採水工程Aを実行する。この採水工程10では例えば水道管の流れ方向に離隔した異なる箇所から水道水(水試料)を採取する。具体的には、水道管の上流及び下流に連結した消火栓や空気弁から水試料を採取する。水試料の採取タイミングは例えば消火栓の開栓時、開栓から5分経過後、或いは、15分経過後など複数考えられるが、消火栓開栓時の水は消火栓自体の腐食に起因した物質が混入している場合があるため、消火栓腐食等の影響から回避するため、例えば開栓から15分経過した後に採取するようにしてもよい。また、水試料の採水量は僅かな採取料で懸濁態元素の濃度分析が可能であるならば、例えば1L(リットル)程度の僅かな水量でも支障はないが、濃度分析のため多くの水量が必要であれば、例えば30L程度を採取するようにしてもよい。
First, the water sampling process A which collects a water sample from two points of the flow direction of a water pipe is performed. In this
次に、採取した水試料から懸濁物を採取する採取工程Bに移行する。懸濁物の採取方法としては、例えば水試料をメンブレンフィルターを用いて、上記1〜30Lの水試料をろ過し懸濁物を採取する。 Next, the process proceeds to a collection step B where a suspension is collected from the collected water sample. As a method for collecting the suspension, for example, the water sample is filtered using the membrane filter and the 1-30 L water sample is filtered to collect the suspension.
続いて、採取した懸濁物の懸濁態元素濃度の測定工程Cに移行する。この工程では、採取した懸濁物を予め硝酸や過塩素酸を用いて溶解し、この溶解懸濁物を誘導結合プラズマ(ICP;Inductively Coupled Plasma)装置で分析し懸濁態元素濃度を測定する。このICP装置としてICP発光分光分析(AES;Atomic Emission Spectrometry)装置やICP質量分析(MS;Mass Spectrometry)装置が用いられ、これらの装置により、Al、Si、Ca、Mn、Fe、Znが分析され、これらの懸濁態元素の濃度を測定される。 Subsequently, the process proceeds to a measurement step C of the suspended element concentration of the collected suspension. In this process, the collected suspension is dissolved in advance using nitric acid or perchloric acid, and this dissolved suspension is analyzed with an inductively coupled plasma (ICP) device to measure the concentration of suspended elements. . As this ICP device, an ICP emission spectroscopy (AES) device or an ICP mass spectrometry (MS) device is used, and Al, Si, Ca, Mn, Fe, and Zn are analyzed by these devices. The concentration of these suspended elements is measured.
更に、懸濁態元素濃度の測定の後、懸濁態元素濃度の変化量の測定工程Dに移行する。水道管から水道水に懸濁物が混入するが、この測定工程Dでは懸濁態元素の混入の程度を分析するため、水道管の下流から採取した水試料の懸濁態元素濃度から上流から採取した水試料の懸濁態元素濃度を減算して測定した。なお、定量限界値以下の濃度については値を0(ゼロ)としたうえで濃度計算を行い、また、上記減算により値が負となった場合は、値は0(ゼロ)として計算した。 Further, after measuring the suspended element concentration, the process proceeds to a measuring step D for measuring the amount of change in suspended element concentration. Suspensions are mixed into the tap water from the water pipe. In this measurement step D, from the upstream from the suspended element concentration of the water sample collected from the downstream of the water pipe in order to analyze the degree of contamination of the suspended elements. The suspended water element concentration of the collected water sample was subtracted and measured. The concentration was calculated after setting the value to 0 (zero) for the concentration below the limit of quantification, and when the value became negative by the subtraction, the value was calculated as 0 (zero).
最後に、懸濁態元素濃度の変化量を用いた水質解析工程Eに移行する。この水質解析工程Eでは多変量解析、例えば主成分分析によって解析する。なお、主成分分析は統計ソフトウェアによって実施した。 Finally, the process proceeds to the water quality analysis step E using the change amount of the suspended element concentration. In this water quality analysis step E, analysis is performed by multivariate analysis, for example, principal component analysis. The principal component analysis was performed with statistical software.
前記実施形態で示した水道管の老朽化判定方法の実施例を以下に説明する。 An example of the method for determining aging of a water pipe shown in the embodiment will be described below.
老朽化判定方法の対象となっている水道管は、図2に示すように、浄水場からポンプ場に配水し、その後、ポンプ場から配水池に導水する水道管1a,1c、また、配水池の水を配水する水道管1b,1d、更に、浄水場の水を直に配水する水道管1e,1f,1gである。
As shown in Fig. 2,
各水道管1a〜1gは、図3に示すように、各種異なる管材となっている。即ち、水道管1a,1cはモルタルライニング鋼管であり、水道管1bは鋼管であり、水道管1d,1gはモルタルライニングダクタイル鋳鉄管であり、1e,1fは樹脂ライニング鋳鉄管である。また、各水道管1a〜1gの敷設後の年数は、水道管1aは38年、水道管1bは46年〜55年(正確な年数は不明、おおよその時期より算出した)、水道管1cは41年、水道管1dは20年となっている。また、水道管1e,1fはそれぞれ27年と29年(昭和30年代後半〜40年代に敷設され、水道管1eは昭和59年に、水道管1fは昭和57年にそれぞれ補修として洗管と樹脂ライニングを実施した)となっている。更に、水道管1gは21年である。
As shown in FIG. 3, each of the water pipes 1 a to 1 g is a variety of different pipe materials. That is, the
以上のような状況となっている水道管1a〜1gについて、水試料の採水工程A(採水量;7L又は20L)、懸濁物の採取工程B(定容;50mL)、懸濁態濃度の測定工程C(ICP−AESを使用)、懸濁態元素濃度変化量の測定工程Dを順次行い、水質解析工程E(主成分分析)を行った。 About water pipe 1a-1g used as the above situations, water sample sampling process A (sample volume; 7L or 20L), suspension sampling process B (constant volume; 50mL), suspension concentration Measurement step C (using ICP-AES) and measurement step D of suspended element concentration change were sequentially performed, and water quality analysis step E (principal component analysis) was performed.
主成分分析の結果は図5に示すとおりである。各成分の寄与率は第1主成分が43%、第2主成分が36%であり、第1及び第2主成分の累積寄与率は79%であった。また、各主成分の因子負荷量は図4に示すとおりである。 The result of the principal component analysis is as shown in FIG. The contribution ratio of each component was 43% for the first principal component and 36% for the second principal component, and the cumulative contribution ratio of the first and second principal components was 79%. In addition, the factor loading of each main component is as shown in FIG.
因子負荷量により、第1主成分はAl(0.83),Mn(0.93),Fe(0.85)と強い正の相関を有しており、第2主成分はCa(−0.9)と負の相関が強いことがわかる。懸濁態濃度の上昇要因として、第1主成分は腐食生成物の剥離が影響し、また、第2主成分はCaを多量に含むライニング等の影響を示していることが分かる。 Depending on the factor loading, the first principal component has a strong positive correlation with Al (0.83), Mn (0.93), and Fe (0.85), and the second principal component is Ca (−0). .9) and the negative correlation is strong. As the increase factor of the suspension concentration, it can be seen that the first main component is influenced by the peeling of the corrosion product, and the second main component shows the influence of the lining containing a large amount of Ca.
以上のように、本発明に係る配水管の老朽化判定方法によれば、各種の水道管1a〜1gの老朽化状況が水質解析工程Eによって明瞭に判断することができるし、また、その解析は各水道管1a〜1gの流れ方向に離隔した異なる箇所から採取した水試料に基づくものであるから、各水道管1a〜1gはそれぞれ管全体の老朽化状況を的確に判定できる。 As described above, according to the method for determining aging of water pipes according to the present invention, the aging status of various water pipes 1a to 1g can be clearly determined by the water quality analysis step E, and the analysis thereof. Is based on water samples collected from different locations separated in the flow direction of the water pipes 1a to 1g, so that each water pipe 1a to 1g can accurately determine the aging status of the whole pipe.
また、従来の老朽化判定方法とは異なり、水道管の掘り返し作業が不要であり、また、衝撃波発生装置等の大がかりな装置も不要となっているため、コストの点でも割安となっている。 Further, unlike the conventional aging determination method, the work of digging up the water pipe is not necessary, and a large-scale device such as a shock wave generator is not required, so that it is also cheaper in terms of cost.
更に、水質解析工程Eの結果、図5に示すように、管種によって分かれる結果、即ち、モルタルライニング鋼管1a,1c、モルタルライニングダクタイル鋳鉄管1d,1g及び樹脂ライニング鋳鉄管1f,1gがそれぞれに分かれる結果となっているため、埋設された水道管の管種が不明な場合であっても、本判定方法により水道管の管種判定としても利用できる。
Further, as a result of the water quality analysis step E, as shown in FIG. 5, the results divided according to the pipe type, that is, mortar
なお、多変量解析として主成分分析を用いているが、多次元尺度構成法を用いるようにしてもよい。 Although the principal component analysis is used as the multivariate analysis, a multidimensional scale construction method may be used.
1a〜1g…水道管。 1a-1g ... water pipe.
更に、懸濁態元素濃度の測定の後、懸濁態元素濃度の変化量の測定工程Dに移行する。水道管から水道水に懸濁物が混入するが、この測定工程Dでは懸濁態元素の混入の程度を分析するため、水道管の下流から採取した水試料の懸濁態元素濃度から上流から採取した水試料の懸濁態元素濃度を減算して測定した。なお、定量限界値以下の濃度については値を0(ゼロ)としたうえで濃度計算した。 Further, after measuring the suspended element concentration, the process proceeds to a measuring step D for measuring the amount of change in suspended element concentration. Suspensions are mixed into the tap water from the water pipe. In this measurement step D, from the upstream from the suspended element concentration of the water sample collected from the downstream of the water pipe in order to analyze the degree of contamination of the suspended elements. The suspended water element concentration of the collected water sample was subtracted and measured. Note that the concentration of the following quantitative limits and density calculations the values upon which the 0 (zero).
Claims (5)
採取した水試料に含まれる懸濁態元素を分析し懸濁態元素の濃度を測定する濃度測定工程と、
異なる水試料の懸濁態元素濃度に基づき懸濁態元素濃度の変化量を計測する変化量計測工程と、
計測された懸濁態元素濃度の変化量に基づき水質解析を行う水質解析工程とを有する
配水管の老朽化判定方法。 A water sampling process for collecting water samples from different locations separated in the flow direction of the water pipe;
A concentration measurement step of analyzing suspended elements contained in the collected water sample and measuring the concentration of suspended elements;
A change amount measuring step for measuring a change amount of the suspended element concentration based on the suspended element concentration of different water samples;
A method for determining aging of distribution pipes, comprising a water quality analysis step for performing water quality analysis based on the measured change in suspended element concentration.
ことを特徴とする請求項1記載の配水管の老朽化判定方法。 The method according to claim 1, wherein the water quality analysis is multivariate analysis.
ことを特徴とする請求項2記載の配水管の老朽化判定方法。 3. The method for determining aging of a water pipe according to claim 2, wherein principal component analysis is used as the multivariate analysis.
ことを特徴とする請求項3記載の配水管の老朽化判定方法。 In the principal component analysis, the first principal component is a suspended element caused by a corrosion product, and the second principal component is a suspended element caused by mortar lining deterioration. To determine the aging of water pipes.
ことを特徴とする請求項4記載の配水管の老朽化判定方法。 The aging determination method for a water pipe according to claim 4, wherein the first main component is at least one of Fe, Al, or Mn, and the second main component is Ca.
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60351A (en) * | 1983-06-16 | 1985-01-05 | Hitachi Ltd | Monitoring method of corrosion |
JPH01246162A (en) * | 1987-12-22 | 1989-10-02 | Denki Kagaku Kogyo Kk | Low alkaline cement composition and lined pipe for water supply using same |
JPH01250841A (en) * | 1988-03-31 | 1989-10-05 | Kubota Ltd | Corrosion predicting method for buried tube |
JP2001041951A (en) * | 1999-07-30 | 2001-02-16 | Hitachi Ltd | Water quality meter, method for measuring water quality, and water quality monitoring system |
JP2003269683A (en) * | 2002-03-18 | 2003-09-25 | Sumitomo Mitsui Construction Co Ltd | Piping survey system |
JP2008267062A (en) * | 2007-04-24 | 2008-11-06 | Kurimoto Ltd | Method and system of predicting deposit amount of turbid substance |
-
2012
- 2012-11-28 JP JP2012259821A patent/JP2014106146A/en active Pending
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60351A (en) * | 1983-06-16 | 1985-01-05 | Hitachi Ltd | Monitoring method of corrosion |
JPH01246162A (en) * | 1987-12-22 | 1989-10-02 | Denki Kagaku Kogyo Kk | Low alkaline cement composition and lined pipe for water supply using same |
JPH01250841A (en) * | 1988-03-31 | 1989-10-05 | Kubota Ltd | Corrosion predicting method for buried tube |
JP2001041951A (en) * | 1999-07-30 | 2001-02-16 | Hitachi Ltd | Water quality meter, method for measuring water quality, and water quality monitoring system |
JP2003269683A (en) * | 2002-03-18 | 2003-09-25 | Sumitomo Mitsui Construction Co Ltd | Piping survey system |
JP2008267062A (en) * | 2007-04-24 | 2008-11-06 | Kurimoto Ltd | Method and system of predicting deposit amount of turbid substance |
Non-Patent Citations (3)
Title |
---|
JPN6015023775; 石渡恭之, 津金大夢, 藤田昌史, 見島伊織: '配水管の管種・使用年数と水道水中懸濁物の構成元素との関係' 全国水道研究発表会講演集 Vol.63rd, 20120424, Page.368-369 * |
JPN6015023776; 石渡恭之 , 津金大夢, 藤田昌史 , 見島伊織: '配水管ネットワークの消火栓から採取した水試料の水質の解析' 日本水環境学会年会講演集 Vol.46th, 20120314, Page.175 * |
JPN7015001630; 石村貞夫 岩村光資郎: 'SPSSによる多変量解析' J.Lumbar Spine Disord. 日本腰痛学会誌8(1), 2002, 21-25 * |
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