JP4237886B2

JP4237886B2 - Inclinometer

Info

Publication number: JP4237886B2
Application number: JP22926699A
Authority: JP
Inventors: 宜伸伊藤; 芳博鈴木
Original assignee: Kyowa Electronic Instruments Co Ltd
Current assignee: Kyowa Electronic Instruments Co Ltd
Priority date: 1999-08-13
Filing date: 1999-08-13
Publication date: 2009-03-11
Anticipated expiration: 2019-08-13
Also published as: JP2001050744A

Description

【０００１】
【発明の属する技術分野】
本発明は、構築物や地中等のような計測対象に埋設し、その傾斜角を計測することにより、計測対象の変状を監視するための傾斜計に関するものである。
【０００２】
【従来の技術】
擁壁および建造物のような構築物や地中等の計測対象の変状を傾斜角の変化に基づいて監視することが行なわれている。すなわち、計測対象の要所要所の傾斜角を計測し、該傾斜角の変化に基づいて計測対象の変形や変位を推定する。このような変状監視は、工事施工中においては施工管理上極めて重要なことであり、施工後においては安全管理上極めて重要なことである。そのためには、傾斜角の微小な変化を、長期にわたって高精度で測定することが可能な傾斜計が必要である。
【０００３】
このような微小な傾斜角を検出する方式としては、ひずみゲージ式、差動トランス式、サーボ式および電磁センサ式等の様々な方式があり、各種の装置が従来から提案され且つ実用に供されている。上述した種々の方式のうち、例えば、温度特性、直線性、長期安定性および応答特性等の点で優れているひずみゲージ式の傾斜計が多用されている。一般に、ひずみゲージ式の傾斜計は、可撓性を有する片持ち梁、すなわちカンチレバーの一端を本体保持部に固定し、その他端に錘（重錘）を取り付け、鉛直線に対してこの傾斜計が傾斜した場合のその傾斜角度（偏角度θ）に比例するカンチレバーの曲げひずみの出力（sinθ）をカンチレバーの面上に添設したひずみゲージの抵抗値の変化から電気的に検出するように構成されている。
【０００４】
具体的には、例えば、地盤の変状を監視する土木計測に傾斜計を用いる場合には、計測対象である地中等にガイドパイプを埋設し、該ガイドパイプ内に多段的に傾斜計を設置して、ガイドパイプの変形による傾斜を深度別に微小な傾斜角として計測することにより、地盤の変状を測定する。
このように、構築物や地中等の計測対象の変状を監視する場合には、傾斜方向は一定ではなく、鉛直線に対して、前後左右のあらゆる方向の傾斜角を計測する必要がある。従来の多くの傾斜計は、一方向に関する傾斜を計測するものであり、鉛直線に対して、前後左右のあらゆる方向の傾斜角を計測するためには、一方向測定用の傾斜計を２個用い、これらを同一軸線上に縦列的に且つ感応方向が直交するように配置して、２方向についての傾斜角を計測し、両方向の傾斜角を合成することにより、多方向の傾斜を観測するようにしていた。
【０００５】
ところが、このように２個の一方向計測用の傾斜計を組み合わせて配置して、多方向の傾斜を計測しようとすると、傾斜計の個数が増えて設置作業、特に埋設作業、が煩雑となり、特に多段に配置する場合には作業性が悪い。しかも、直交配置される一組の傾斜計の一方の計測位置と、他方の計測位置とが高さ方向について大きく相違し、現実には異なる位置の傾斜角度を計測していることになり、正確な傾斜の計測を行なうことができない。
これに対して、単一の傾斜計で直交する２方向についての傾斜角を検出するものとしては、例えば図１３に示すような内部構造を用いた２方向計測用の傾斜計が考えられている。
【０００６】
図１３に示す２方向計測用の傾斜計は、金属製の保持部材１０１に、第１の起歪板１０２および第２の起歪板１０３を順次介して錘１０４を吊下する。第１の起歪板１０２、第２の起歪板１０３および錘１０４は、共通の中心軸線Ｃに沿って配設されている。第１の起歪板１０２および第２の起歪板１０３は、いずれも可撓性を有する帯状の薄板からなり、少なくとも一方の面に変形検知用のひずみゲージが添設されている。第１の起歪板１０２は、一端を保持部材１０１に固定し、他端を第１の連結部材１０５により第２の起歪板１０３の一端に結合して、中心軸線Ｃを含む第１の平面に沿って配置されている。また、第２の起歪板１０３は、一端を第１の連結部材１０５により第１の起歪板１０２の前記他端に結合し、他端に第２の連結部材１０６により錘１０４の上端を結合して、中心軸線Ｃを含み前記第１の平面に直交する第２の平面に沿って配置されている。
【０００７】
第１の起歪板１０２および第２の起歪板１０３は、それぞれ板面に垂直方向への撓み変形を検出して、直交する２方向の傾斜角度を計測する。これら保持部材１０１、第１の起歪板１０２、第２の起歪板１０３、第１の連結部材１０５、第２の連結部材１０６および錘１０４を適宜なるケース（図示せず）に収めて２方向計測用の傾斜計を構成している。
【０００８】
【発明が解決しようとする課題】
上述したような在来の傾斜計には、次のような問題があった。
【０００９】
（１）在来の傾斜計は、一方向計測用の傾斜計を用いた場合、多方向の傾斜を計測するためには、２個で一組での全長が長くなり、ボーリング孔に多段設置することができる傾斜計の最大数に限度があり、使用者の要求に充分に応えることができない。
（２）在来の２方向計測用の傾斜計は、図１３のように、例えばｘ方向の傾斜検出部となる第１の起歪板１０２と、例えばｙ方向の傾斜検出部となる第２の起歪板１０３と、１個の錘１０４とが順次直列に接続される構造のため、小型化が困難である。例えば図１３においては、保持部材１０１に対して第１の起歪板１０２、第１の連結部材１０５および第２の起歪板１０３、第２の連結部材１０６を縦列に介して錘１０４が吊下されるため、保持部材１０１から錘１０４までの距離が長くなり、錘１０４の移動範囲が広くなる。このため、ケースを含めた２方向計測用の傾斜計の外径寸法および長さ寸法が大きくなる。
【００１０】
（３）在来の２方向計測用の傾斜計は、図１３のような縦列連結構造であるため、ｘ方向およびｙ方向の２つの方向の傾斜検出部となる第１の起歪板１０２および第２の起歪板１０３を厳密に直交配置しないと、第１の起歪板１０２および第２の起歪板１０３の計測値および撓み変形に第１の起歪板１０２および第２の起歪板１０３の相互干渉の影響があらわれやすい。
（４）傾斜計を設置する環境によっては、落雷等による雷サージ電圧などの電気的作用を受けることがある。このような、電気的作用を受けると従来の傾斜計は、計測が不安定になったりすることがあり、場合によっては故障することがある。
【００１１】
本発明は、上述した事情に鑑みてなされたもので、その目的とするところは、所定方向の傾斜を高精度に且つ効率よく、しかも高感度で計測することができ、小型化が容易な傾斜計を提供することにある。
本発明に係る請求項１の目的は、特に、２方向の傾斜を、高精度に且つ効率よく、しかも干渉が少なく高感度で計測することができ、２方向計測用として小型化が容易な傾斜計を提供することにある。
本発明に係る請求項２の目的は、特に、２方向のうちの一方向の傾斜計測を、大型化せずに行なうことができ、しかも他方向との干渉も効果的に防止し得る傾斜計を提供することにある。
【００１２】
本発明に係る請求項３の目的は、特に、２方向のうちの一方向の傾斜計測を、より小型の構成にて行なうことができ、しかもその他の方向との干渉も一層効果的に防止し得る傾斜計を提供することにある。
本発明に係る請求項４の目的は、特に、２方向のうちの他方向の傾斜計測を、一層小型の構成にて安定に行なうことができる傾斜計を提供することにある。
本発明に係る請求項５の目的は、特に、２方向のうちの他方向の傾斜計測を、さらに小型化した構成にて安定に行なうことが可能な傾斜計を提供することにある。
【００１４】
【課題を解決するための手段】
請求項１に記載した本発明に係る傾斜計は、上述した目的を達成するために、計測対象に埋設して、その傾斜角を計測するための傾斜計において、
保持部材と、
ほぼ中空円筒状をなす第１の錘と、
それぞれ薄肉帯状をなし、ひずみゲージが添設されて撓み変形可能に構成されるとともに、前記第１の錘の円筒状の中心軸線を通る第１の平面上に前記中心軸線に対して対称的に対をなして配設され、各一端を前記保持部材にそれぞれ結合し且つ各他端を前記第１の錘のほぼ円環状をなす上端面にそれぞれ結合して、前記保持部材から前記第１の錘を吊下する一対の第１の起歪板と、
第２の錘と、
薄肉板状をなし、ひずみゲージが添設されて撓み変形可能に構成されるとともに、前記第１の錘の円筒状の中心軸線上で且つ前記第１の平面と前記中心軸線において直交する第２の平面に沿い、一端を前記保持部材に結合し且つ他端を前記第２の錘に結合して、前記保持部材から前記第１の錘の中心軸線に沿う中空部を通して前記第２の錘を吊下する第２の起歪板と、
前記保持部材、第１の錘、一対の第１の起歪板、第２の錘、および第２の起歪板を収容するケースと
を具備することを特徴としている。
【００１５】
請求項２に記載した本発明に係る傾斜計は、
前記保持部材が、前記第１の錘の円筒状の中心軸線に沿って下方に突出する突出部を有し、且つ前記第２の起歪板の前記一端が、前記突出部に結合されることを特徴としている。
請求項３に記載した本発明に係る傾斜計は、
前記第２の錘が、前記第１の錘の円筒状の中心軸線に沿って上方に延びる小径部を有し、且つ前記第２の起歪板の前記他端が、前記小径部に結合されることを特徴としている。
【００１６】
請求項４に記載した本発明に係る傾斜計は、
前記第１の錘が、円筒状の外周面の少なくとも下方部位を、該第１の錘の規制すべき作動範囲および前記ケース内面位置に応じて、上方に拡がるテーパ面としたことを特徴としている。
請求項５に記載した本発明に係る傾斜計は、
前記第１の錘が、円筒状の内周面の少なくとも下方部位を、前記第２の錘の規制すべき作動範囲および前記第２の錘の形状に応じて、下方に拡がるテーパ面としたことを特徴としている。
【００１９】
【作用】
すなわち、本発明の請求項１による傾斜計は、ほぼ中空円筒状をなす第１の錘を、それぞれ薄肉帯状をなし、ひずみゲージが添設されて撓み変形可能に構成されるとともに、前記第１の錘の円筒状の中心軸線を通る第１の平面上に前記中心軸線に対して対称的に対をなして配設され、各一端を前記保持部材にそれぞれ結合し且つ各他端を前記第１の錘の円環状をなす上端面にそれぞれ結合する一対の第１の起歪板により、前記保持部材から前記第１の錘を吊下し、薄肉板状をなし、ひずみゲージが添設されて撓み変形可能に構成されるとともに、前記第１の錘の円筒状の中心軸線上で且つ前記第１の平面と前記中心軸線において直交する第２の平面に沿い、一端を前記保持部材に結合し且つ他端を前記第２の錘に結合する第２の起歪板により、前記保持部材から前記第１の錘の中心軸線に沿う中空部を通して前記第２の錘を吊下して、ケースに収容する。
このような構成により、２方向の傾斜を、高精度に且つ効率よく、しかも干渉が少なく高感度で計測することができ、小型化も容易である。
【００２０】
また、本発明の請求項２による傾斜計は、前記保持部材が、前記第１の錘の円筒状の中心軸線に沿って下方に突出する突出部を有し、且つ前記第２の起歪板の前記一端が、前記突出部に結合される。
このような構成により、特に、２方向のうちの一方向の傾斜計測を、大型化せずに行なうことができ、しかも他方向との干渉も効果的に防止し得る。
本発明の請求項３による傾斜計は、前記第２の錘が、前記第１の錘の円筒状の中心軸線に沿って上方に延びる小径部を有し、且つ前記第２の起歪板の前記他端が、前記小径部に結合される。
このような構成により、特に、２方向のうちの一方向の傾斜計測を、より小型の構成にて行なうことができ、しかもその他の方向との干渉も一層効果的に防止し得る。
【００２１】
本発明の請求項４による傾斜計は、前記第１の錘が、円筒状の外周面の少なくとも下方部位を、該第１の錘の規制すべき作動範囲および前記ケース内面位置に応じて、上方に拡がるテーパ面とする。
このような構成により、特に、２方向のうちの他方向の傾斜計測を、一層小型の構成にて安定に行なうことができる。
本発明の請求項５による傾斜計は、前記第１の錘が、円筒状の内周面の少なくとも下方部位を、前記第２の錘の規制すべき作動範囲および前記第２の錘の形状に応じて、下方に拡がるテーパ面とする。
このような構成により、特に、２方向のうちの他方向の傾斜計測を、さらに小型化した構成にて安定に行なうことが可能である。
【００２４】
【発明の実施の形態】
以下、実施の形態に基づき、図面を参照して本発明の傾斜計を詳細に説明する。
図１〜図３は、本発明の第１の実施の形態に係る２方向計測用の傾斜計の構成を示している。図１は、据え付け構造を含む２方向計測用の傾斜計全体の斜視図であり、図２は、２方向計測用の傾斜計単体の縦断面図、そして図３は、２方向計測用の傾斜計のケース内部の斜視図を示している。
【００２５】
図１〜図３に示す傾斜計は、保持部材１、第１の起歪板２Ａおよび２Ｂ、第１の錘３、第２の起歪板４、第２の錘５、ケース６、第１のガイド部材７、並びに第２のガイド部材８を有しており、さらに図１には接続ロッド９および１０、並びにケーブル１１を示している。保持部材１、第１の起歪板２Ａおよび２Ｂ、第１の錘３、第２の起歪板４、第２の錘５、ケース６、第１のガイド部材７、並びに第２のガイド部材８により、傾斜計２０を形成している。
【００２６】
保持部材１は、例えば絶縁体材料を用いて短寸円柱状に形成され、その中央軸線上に下方に突出する突出部１ａを有している。対をなす第１の起歪板２Ａおよび２Ｂは、それぞれ薄肉帯板状をなし、中心軸線を通る第１の平面上における保持部材１の突出部１ａの両側に中心軸線に対して対称に且つ両者とも該中心軸線に平行に配設される（図２参照）。これら第１の起歪板２Ａおよび２Ｂは、可撓性を有し、それぞれの両面または片面にひずみゲージ（図示せず）が接着、蒸着等の手段により添設されれていて、撓み変形の大きさを計測することができるようになっている。対をなす第１の起歪板２Ａおよび２Ｂの各々の一端は、保持部材１の下面の突出部１ａの両側に固定され、各々の他端は、第１の錘３の上面に結合されている。
【００２７】
第１の錘３は、両端を開放した中空円筒状に形成され、その上端面は、上端部のほぼ半円周分を切欠した形状の段差を有してほぼ円環状をなしており、その段差壁面に対をなす第１の起歪板２Ａおよび２Ｂの各々の他端を結合している。すなわち、対をなす第１の起歪板２Ａおよび２Ｂの各々の他端を、固定ブロック３ａおよび３ｂによって第１の錘３の段差壁面に固定する。したがって、第１の錘３は、保持部材１に一対の第１の起歪板２Ａおよび２Ｂを介して吊下される。
【００２８】
第２の起歪板４は、薄肉帯板状をなし、中心軸線を通り且つ前記第１の平面に中心軸線にて直交する第２の平面上における保持部材１の突出部１ａの先端面の下方に配設される。この第２の起歪板４は、可撓性を有し、その両面または片面にひずみゲージ（図示せず）が添設されれていて、撓み変形の大きさを計測することができるようになっている。第２の起歪板４の一端は、保持部材１の突出部１ａの下面に固定され、他端は、第２の錘５の上端に結合されている。
第２の錘５は、円柱状の上側部位を上方に延びる小径部５ａとして形成し、その上端面は、円形をなしており、その円形に第２の起歪板４の他端を結合している。したがって、第２の錘５も、保持部材１に第２の起歪板４を介して吊下される。
【００２９】
なお、第１の錘３は、少なくとも下端側部位の外周部を上方に向かって拡がるテーパ面に形成して（図２参照）、第１の錘３の可動範囲を確保するとともに、適正な可動範囲を超えないように可動範囲を規制している。また、第１の錘３は、中心軸線に沿う中空部の少なくとも下端側の部位の内面を下方に向かって拡がるテーパ面に形成して、この内部で動作する第２の錘５の可動範囲を確保するとともに、適正な可動範囲を超えないように可動範囲を規制している。
ケース６は、例えば両端を閉塞した円筒状をなし、上述した保持部材１、第１の起歪板２Ａ、２Ｂ、第１の錘３、第２の起歪板４および第２の錘５の各部を収容する。ケース６の内面には、電気的絶縁被覆が施されている。なお、ケース６内には、微振動の影響をなくすためにダンピングオイル等が封入されている。
【００３０】
第１のガイド部材７は、ケース６の上端に固定され、この場合、第２の起歪板４が配設される第２の平面に沿う板状をなして両側方に突出するガイド翼部７ａおよび７ｂを有する。第２のガイド部材８は、ケース６の下端に固定され、この場合、第２の起歪板４が配設される第２の平面に沿う板状をなして両側方に突出するガイド翼部８ａおよび８ｂを有する。これら各部により、２方向計測用の傾斜計２０を構成している。第１のガイド部材７のガイド翼部７ａ、７ｂ、第２のガイド部材８のガイド翼部８ａおよび８ｂは、埋設時にこれらガイド翼部８ａおよび８ｂに嵌合するガイドパイプ（図示省略）のガイド溝あるいはガイドレール等を用いて、傾斜計２０の向きを正しく設定するために設けられている。
【００３１】
例えば、ガイドパイプに多段に配置する場合には、計測対象に鉛直に埋設したガイドパイプに形成されたガイド溝にガイド翼部８ａおよび８ｂを嵌合させて複数個の傾斜計２０を１個ずつ設置し、これら傾斜計２０相互間には、傾斜計２０の間隔を規定する接続ロッド９および１０等を設置する。すなわち、複数の傾斜計２０は、ガイド翼部８ａおよび８ｂをガイドパイプのガイド溝に嵌合させて所定の姿勢つまり向きを維持しつつ、相互間隔を規定する接続ロッド９および１０等により所定間隔で連結されて、ガイドパイプ内に順次挿入されて多段に設置される。
【００３２】
ケーブル１１は、傾斜計２０の第１の起歪板２Ａ、２Ｂおよび第２の起歪板４に添設されたひずみゲージの電気信号を伝達する。傾斜計２０の第１の起歪板２Ａ、２Ｂおよび第２の起歪板４に添設されたひずみゲージの出力電気信号は、ケーブル１１を介して外部に取り出され、個々の傾斜計２０毎の傾斜角度の解析に供される。傾斜計２０の第１の起歪板２Ａ、２Ｂおよび第２の起歪板４に対する給電もケーブル１１を介して行なわれる。
【００３３】
図４は、上述した傾斜計２０を土留め工法における掘削境界面の変状測定に用いる場合の具体的な構成例を示している。
土留め工法とは、掘削による周辺地盤の崩壊および掘削面からの地下水の流入を防ぐための工法である。この土留め工法では、予め掘削境界面に鋼矢板等を用いて連続する土留め壁２１を打設して地盤掘削を行なう。掘削に伴い、隣接した周辺地盤２２上に設置された既設の建造物に発生する傾斜および変位を極力少なくするために、土留め壁２１が設けられる。土留め壁２１は、掘削の進行に際して、安定に保持しなければならないため、腹起こし２３および切りばり２４などを順次設けて、周辺地盤２２と掘削地盤２５との段差部において土留め壁２１を支える。
【００３４】
そのために、情報化施工管理に伴う土留め計測管理が非常に重要となる。土留め壁２１には、鋼矢板を用いるものの他に、鋼管または大深度での鉄筋コンクリート製の連続壁などがある。この土留め壁２１部分で傾斜計２０等を用いた土留め計測が行なわれる。
土留め計測に埋設型の傾斜計２０を用いる場合には、図４に示すように土留め壁２１の近傍に、鉛直方向に沿って例えばアルミニウム製のガイドパイプ２６を最大計測深度に至るまで埋設する。既に述べたように、ガイドパイプ２６には複数の傾斜計２０を、接続ロッドで連結しながら各々所要の計測深度に合わせて多段に挿入する。最後に、ガイドパイプ２６内の空隙にセメントミルク２７を充填して固める。
【００３５】
地盤掘削が開始され、土留め壁２１が掘削側に傾き変形し始めると、その近傍に設置されたガイドパイプ２６もこれに従って同様に変形する。ガイドパイプ２６内の傾斜計２０は、ガイドパイプ２６の変形に応じて傾斜し、土留め壁２１の各深度における傾斜を検出する。この傾斜角と傾斜計２０間の距離に基づいて、各深度間での側方変位が計算される。最大深度地点を基準つまり不動点として、上方深度における側方変位を順次加算することにより、累積側方変位が求められ、その結果に基づいて土留め壁２１全体の変状を確認することができる。なお、大規模な土留め工法等においては、ガイドパイプ２６を使用せずに、鉄筋コンクリート製の連続壁に傾斜計２０を直接埋設して計測する場合もある。
【００３６】
上述した傾斜計２０は、次のような特徴を有している。
傾斜計２０は、第１の錘３を吊下して傾斜角に応じた撓みを生じる起歪板として、２枚つまり一対の第１の起歪板２Ａおよび２Ｂを用い、同一の第１の平面上に間隙を存して配置することにより、第１の起歪板２Ａおよび２Ｂの撓み方向と直角方向に作用するモーメント力を小さくする。また、撓み方向の変位について、第１の錘３の形状を、外面の少なくとも下端側を上方に拡がるテーパ状として最適化し、ケース６内における第１の錘３の移動範囲を制限することにより、第１の起歪板２Ａおよび２Ｂを過負荷から保護するようにしている。さらに第２の錘５についても第１の錘３の内面の少なくとも下端側を下方に拡がるテーパ状として最適化し、第１の錘３内における第２の錘５の移動範囲を制限することにより、第２の起歪板４を過負荷から保護するようにしている。
【００３７】
このように構成することにより、傾斜計２０に、誤って過大な傾斜負荷が加わった場合に、傾斜計２０の検出部が保護されるので、信頼性が向上し、取り扱いが容易となる。しかも、傾斜計２０は、可動部分の全長が短く、可動部分の構成を最適化して、スペース効率を高めており、傾斜計２０のケース６を含む外径寸法および全長を小さくできるため、従来よりも多段に傾斜計を設置することができる。
【００３８】
２方向測定用の傾斜計２０においては、例えば、Ｘ軸方向の傾斜検出部、並びにＹ軸方向の傾斜検出部として用いられる第１の起歪板２Ａおよび２Ｂ、並びに第２の起歪板４は、それぞれ別個に第１の錘３、並びに第２の錘５を有し、互いの検出部を完全に独立させている。なお、適正に変形させひずみゲージでひずみを効率よく検出させるためには、起歪板の寸法形状に制限があり、しかも保持部材１から第１の錘３または第２の錘５の先端までの距離は、それぞれ第１の錘３または第２の錘５の移動範囲を決定するので、それらを考慮して保持部材１の突出部１ａ、第２の錘５の小径部５ａ等の寸法を決定する。
【００３９】
このように、２方向測定用の傾斜計２０において、２方向の検出部である第１の起歪板２Ａ、２Ｂ、および第２の起歪板４をそれぞれ独立させることにより、相互干渉がなくなり、しかも第１の起歪板２Ａ、２Ｂ、および第２の起歪板４の設置される位置が深さ方向について近接させることが容易であるため、測定精度を著しく向上させることができる。また、たとえ一方の傾斜検出部が機械的に故障しても、他方の検出部が影響を受けることがない。
第１および第２の起歪板２Ａ、２Ｂおよび第２の起歪片４を保持する保持部材１に電気的絶縁体を用い、または、その表面に電気的絶縁被覆を設け、且つケース６の内面および錘３，５の表面に電気的絶縁被覆を設けることにより、傾斜計２０におけるひずみゲージ部分等の電気回路部分とケース外部との間の絶縁を行なって、落雷時の雷サージ等による内部放電を防止するようにしている。
尚、絶縁処理は、上述した部材の全てに施すことが望ましいが、必らずしも全てに施すことなく、保持部材１、ケース６および鏡３，５のうち、いずれか１つを電気的絶縁体で構成するか、またはその表面に絶縁被覆を設けるようにしてもよい。
【００４０】
このように、ひずみゲージを添設した第１の起歪板２Ａ、２Ｂ、および第２の起歪板４を保持する保持部材１を絶縁体で構成し、且つケース６内面に絶縁被覆を設けて、雷サージ電圧などによる傾斜計２０内部での放電を発生しにくくしているので、測定精度および信頼性が向上する。
上述のような傾斜計２０の特性を測定した実験結果を図５〜図１１を参照して説明する。実験は、定格容量が傾斜角−５°〜５°のものと、定格容量が傾斜角−１０°〜１０°のものとを用いて行なった。
【００４１】
（１）出力特性
定格容量が傾斜角−５°〜５°のもの、および定格容量が傾斜角−１０°〜１０°のものについて、構成における非直線性およびヒステリシスの試験結果は、図５に示す通りであった。図５の（ａ）および（ｂ）は、それぞれ定格容量が傾斜角−５°〜５°のもののＸ軸方向の出力偏差およびＹ軸方向の出力偏差を示している。図５の（ｃ）および（ｄ）は、それぞれ定格容量が傾斜角−１０°〜１０°のもののＸ軸方向の出力偏差およびＹ軸方向の出力偏差を示している。図５のいずれにおいても出力偏差が±０．５％ＲＯ以内に収まっていることがわかる。
【００４２】
（２）零点の温度影響
温度補償範囲−１０℃〜６０℃において、傾斜角を加えずに測定した零点の温度影響の試験結果を図６に示す。図６の（ａ）および（ｂ）は、それぞれ定格容量が傾斜角−５°〜５°のもののＸ軸方向の出力変化およびＹ軸方向の出力変化を示している。図６の（ｃ）および（ｄ）は、それぞれ定格容量が傾斜角−１０°〜１０°のもののＸ軸方向の出力変化およびＹ軸方向の出力変化を示している。図６のいずれにおいても、±３５℃の変化で±１．５％ＲＯ以内の零点の変化量であり、規模値の±０．０５％ＲＯ／℃以内である。
【００４３】
（３）出力の温度影響
−１０℃、２５℃、および６０℃の環境下において測定した出力の温度影響の試験結果を図７に示す。図７は、定格容量が傾斜角−５°〜５°のものの出力変化を示している。図７においては、±３５℃の変化で±１．５％以内の出力の変化量であり、規模値の±０．１％／℃以内である。
（４）長期安定性
恒温室内において定格負荷を加え、１５０日以上の長期安定度試験を行なった結果を図８に示す。図８（ａ）および（ｂ）は、それぞれ定格容量が傾斜角−５°〜５°のもののＸ軸方向の出力変化およびＹ軸方向の出力変化を示している。図８においては、出力の変動幅は最大でも±０．２５％ＲＯ（１５０日）以内であり、優れた長期安定性を有していることがわかる。
【００４４】
（５）横感度比
感度方向に対して直角方向に負荷を加えた場合の出力の変化量を測定した結果を図９に示す。図９の（ａ）、および（ｂ）は、それぞれ定格容量が傾斜角−５°〜５°のものの感度方向に対して直角方向負荷による出力偏差、および定格容量が傾斜角−１０°〜１０°のものの感度方向に対して直角方向負荷による出力偏差を示している。感度方向の出力に対して、横感度比は±０．２％ＲＯ程度である。
【００４５】
（６）傾斜状態での任意方向出力
傾斜計２０を傾斜させた状態で、傾斜計２０の中心軸線（Ｚ軸）まわりに３６０°回転させたときのＸ軸およびＹ軸の出力を図１０に示す。図１０の（ａ）、および（ｂ）は、それぞれ定格容量が傾斜角−５°〜５°のものの傾斜状態で回転させたときの出力、および定格容量が傾斜角−１０°〜１０°のものの傾斜状態で回転させたときの出力を示している。いずれにおいても、理論値の正弦波に沿った出力を確認することができる。
【００４６】
（７）応答時間
傾斜計２０は、微振動の影響をなくすために、ケース６内にオイルが封入されている。傾斜計２０を常温にて素早く定格負荷まで傾斜させ、出力が安定するまでの時間を測定した結果を図１１に示す。図１１（ａ）および（ｂ）は、それぞれ定格容量が傾斜角−５°〜５°のもののＸ軸方向の出力変化およびＹ軸方向の出力変化を示している。図１１においては、Ｘ軸について６分程度、Ｙ軸について３分程度で出力が安定する。
【００４７】
図１２は、本発明の第２の実施の形態に係る１方向計測用の傾斜計の構成を示している。
図１２は、１方向計測用の傾斜計単体の縦断面図を示している。図１２の傾斜計は、図１〜図３に示した２方向計測用の傾斜計２０から一方の検出部である第２の起歪板４および第２の錘５を除去し、ケース６を小型化したものであり、図１〜図３と同様の部分には同符号を付してその詳細な説明を省略する。
図１２に示す傾斜計３０は、保持部材１、起歪板２Ａおよび２Ｂ、錘３、ケース６′、第１のガイド部材７、並びに第２のガイド部材８を有しており、さらに図１２にはケーブル１１を示している。
【００４８】
この場合、図１〜図３に示した２方向計測用の傾斜計２０から一方の検出部である第２の起歪板４および第２の錘５を除去しているのでその部分のスペースが不要となり、ケース６′特にその全長を短寸に、且つ高感度に構成することができる。
なお、本発明は、上述した実施の形態にのみ限定されるものではなく、その要旨に含まれる範囲内において、種々変形して実施することができる。
【００４９】
【発明の効果】
以上述べたように、本発明の請求項１によれば、ほぼ中空円筒状をなす第１の錘を、それぞれ薄肉帯状をなし、ひずみゲージが添設されて撓み変形可能に構成されるとともに、前記第１の錘の円筒状の中心軸線を通る第１の平面上に前記中心軸線に対して対称的に対をなして配設され、各一端を前記保持部材にそれぞれ結合し且つ各他端を前記第１の錘の円環状をなす上端面にそれぞれ結合する一対の第１の起歪板により、前記保持部材から前記第１の錘を吊下し、薄肉板状をなし、ひずみゲージが添設されて撓み変形可能に構成されるとともに、前記第１の錘の円筒状の中心軸線上で且つ前記第１の平面と前記中心軸線において直交する第２の平面に沿い、一端を前記保持部材に結合し且つ他端を前記第２の錘に結合する第２の起歪板により、前記保持部材から前記第１の錘の中心軸線に沿う中空部を通して前記第２の錘を吊下して、ケースに収容する構成により、２方向の傾斜を、高精度に且つ効率よく、しかも干渉が少なく高感度で計測することができ、小型化も容易な傾斜計を提供することができる。
【００５０】
本発明の請求項２の傾斜計によれば、前記保持部材が、前記第１の錘の円筒状の中心軸線に沿って下方に突出する突出部を有し、且つ前記第２の起歪板の前記一端が、前記突出部に結合される構成により、特に、２方向のうちの一方向の傾斜計測を、大型化せずに行なうことができ、しかも他方向との干渉も効果的に防止し得る。
本発明の請求項３の傾斜計によれば、前記第２の錘が、前記第１の錘の円筒状の中心軸線に沿って上方に延びる小径部を有し、且つ前記第２の起歪板の前記他端が、前記小径部に結合される構成により、特に、２方向のうちの一方向の傾斜計測を、より小型の構成にて行なうことができ、しかもその他の方向との干渉も一層効果的に防止し得る。
【００５１】
本発明の請求項４の傾斜計によれば、前記第１の錘が、円筒状の外周面の少なくとも下方部位を、該第１の錘の規制すべき作動範囲および前記ケース内面位置に応じて、上方に拡がるテーパ面とすることにより、特に、２方向のうちの他方向の傾斜計測を、一層小型の構成にて安定に行なうことができる。
本発明の請求項５の傾斜計によれば、前記第１の錘が、円筒状の内周面の少なくとも下方部位を、前記第２の錘の規制すべき作動範囲および前記第２の錘の形状に応じて、下方に拡がるテーパ面とすることにより、特に、２方向のうちの他方向の傾斜計測を、さらに小型化した構成にて安定に行なうことが可能である。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態に係る傾斜計の構成を一部を切欠して模式的に示す斜視図である。
【図２】図１の傾斜計の構成を模式的に示す縦断面図である。
【図３】図１の傾斜計のケース内の構成を模式的に示す斜視図である。
【図４】図１の傾斜計の設置例を説明するための模式的斜視図である。
【図５】図１の傾斜計における実験による出力特性例を示す図である。
【図６】図１の傾斜計における実験による零点の温度特性例を示す図である。
【図７】図１の傾斜計における実験による出力の温度特性例を示す図である。
【図８】図１の傾斜計における実験による長期安定度の例を示す図である。
【図９】図１の傾斜計における実験による横感度比の例を示す図である。
【図１０】図１の傾斜計における実験による傾斜状態での任意方向出力の例を示す図である。
【図１１】図１の傾斜計における実験による応答時間特性の例を示す図である。
【図１２】本発明の第２の実施の形態に係る一方向計測用の傾斜計の構成を模式的に示す縦断面図である。
【図１３】従来の２方向計測用の傾斜計の構成を模式的に示す斜視図である。
【符号の説明】
１保持部材
１ａ突出部
２Ａ，２Ｂ第１の一方、他方の起歪板
３第１の錘
３ａ，３ｂ固定ブロック
４第２の起歪板
５第２の錘
６，６′ ケース
７第１のガイド部材
７ａ，７ｂガイド翼部
８第２のガイド部材
８ａ，８ｂガイド翼部
９，１０接続ロッド
１１ケーブル
２０傾斜計
２６ガイドパイプ
２７セメントミルク
３０傾斜計[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inclinometer for embedding in a measurement object such as a structure or underground, and monitoring the deformation of the measurement object by measuring its inclination angle.
[0002]
[Prior art]
Monitoring of deformation of a measurement object such as a retaining wall and a structure such as a building or underground is performed based on a change in inclination angle. That is, the inclination angle of a necessary point of the measurement target is measured, and the deformation or displacement of the measurement target is estimated based on the change in the inclination angle. Such deformation monitoring is extremely important for construction management during construction, and is extremely important for safety management after construction. For this purpose, an inclinometer capable of measuring a minute change in tilt angle with high accuracy over a long period of time is required.
[0003]
There are various methods such as strain gauge type, differential transformer type, servo type and electromagnetic sensor type for detecting such a small inclination angle, and various devices have been proposed and put to practical use. ing. Among the various methods described above, for example, strain gauge type inclinometers that are excellent in terms of temperature characteristics, linearity, long-term stability, response characteristics, and the like are frequently used. Generally, a strain gauge type inclinometer is a cantilever having flexibility, that is, one end of a cantilever is fixed to a main body holding portion, and a weight (weight) is attached to the other end, and this inclinometer is attached to a vertical line. The cantilever's bending strain output (sinθ) proportional to the tilt angle (deviation angle θ) of the cantilever is detected from the change in the resistance value of the strain gauge attached on the cantilever surface. Has been.
[0004]
Specifically, for example, when an inclinometer is used for civil engineering measurement to monitor ground deformation, a guide pipe is embedded in the ground to be measured, and the inclinometer is installed in multiple stages in the guide pipe. Then, the deformation of the ground is measured by measuring the inclination due to the deformation of the guide pipe as a minute inclination angle according to the depth.
Thus, when monitoring the deformation of a measurement object such as a structure or underground, the inclination direction is not constant, and it is necessary to measure inclination angles in all directions, front, rear, left, and right with respect to the vertical line. Many conventional inclinometers measure the inclination in one direction. In order to measure the inclination angle in all directions, front, back, left, and right with respect to the vertical line, two inclinometers for unidirectional measurement are provided. These are arranged in tandem on the same axis so that the sensitive directions are orthogonal to each other, and the inclination angles in two directions are measured, and the inclination angles in both directions are combined to observe multi-directional inclinations. It was like that.
[0005]
However, when two inclinometers for unidirectional measurement are combined and arranged to measure multi-directional inclinometers, the number of inclinometers increases and installation work, particularly embedding work, becomes complicated. In particular, the workability is poor when it is arranged in multiple stages. Moreover, one measurement position of a set of inclinometers arranged orthogonally and the other measurement position are greatly different in the height direction, and in reality, the inclination angles at different positions are being measured. It is impossible to measure the inclination.
On the other hand, for detecting an inclination angle in two directions orthogonal to each other with a single inclinometer, for example, an inclinometer for two-direction measurement using an internal structure as shown in FIG. 13 is considered. .
[0006]
The inclinometer for two-direction measurement shown in FIG. 13 suspends a weight 104 from a metal holding member 101 via a first strain plate 102 and a second strain plate 103 in order. The first strain generating plate 102, the second strain generating plate 103, and the weight 104 are disposed along a common central axis C. Each of the first strain generating plate 102 and the second strain generating plate 103 is a flexible strip-shaped thin plate, and a strain gauge for detecting deformation is attached to at least one surface. The first strain plate 102 has one end fixed to the holding member 101 and the other end coupled to one end of the second strain plate 103 by the first connecting member 105, and includes a first axis C. It is arranged along a plane. The second strain plate 103 is connected at one end to the other end of the first strain plate 102 by a first connecting member 105 and at the other end the upper end of the weight 104 by a second connecting member 106. They are coupled and arranged along a second plane that includes the central axis C and is orthogonal to the first plane.
[0007]
Each of the first strain plate 102 and the second strain plate 103 detects bending deformation in a direction perpendicular to the plate surface, and measures an inclination angle in two orthogonal directions. The holding member 101, the first strain generating plate 102, the second strain generating plate 103, the first connecting member 105, the second connecting member 106, and the weight 104 are housed in an appropriate case (not shown). It constitutes an inclinometer for measuring direction.
[0008]
[Problems to be solved by the invention]
The conventional inclinometer as described above has the following problems.
[0009]
(1) Conventional inclinometers, when using inclinometers for unidirectional measurement, have a total length of two in one set to measure multidirectional inclinations, and are installed in multiple stages in the borehole There is a limit to the maximum number of inclinometers that can be done and cannot fully meet the user's requirements.
(2) As shown in FIG. 13, the conventional inclinometer for two-direction measurement includes, for example, a first strain generating plate 102 serving as a tilt detection unit in the x direction and a second strain detection unit serving as a tilt detection unit in the y direction. The strain generating plate 103 and the single weight 104 are sequentially connected in series, so that it is difficult to reduce the size. For example, in FIG. 13, the weight 104 is suspended from the holding member 101 through the first strain plate 102, the first connecting member 105, the second strain plate 103, and the second connecting member 106 in tandem. Therefore, the distance from the holding member 101 to the weight 104 is increased, and the moving range of the weight 104 is increased. For this reason, the outer diameter dimension and length dimension of the inclinometer for two-way measurement including a case become large.
[0010]
(3) Since the conventional inclinometer for two-direction measurement has a cascade connection structure as shown in FIG. 13, the first strain plate 102 serving as an inclination detection unit in two directions, the x direction and the y direction, and If the second strain generating plate 103 is not strictly arranged orthogonally, the first strain generating plate 102 and the second strain generating strain will be affected by the measured values and the bending deformation of the first strain generating plate 102 and the second strain generating plate 103. The influence of mutual interference of the plate 103 is likely to appear.
(4) Depending on the environment where the inclinometer is installed, it may be subject to electrical effects such as lightning surge voltage due to lightning strikes. When subjected to such an electrical action, the conventional inclinometer may become unstable in measurement and may fail in some cases.
[0011]
The present invention has been made in view of the above-described circumstances, and an object of the present invention is to be able to measure a tilt in a predetermined direction with high accuracy and efficiency, and with high sensitivity, and can be easily downsized. To provide a total.
The object of the first aspect of the present invention is to be able to measure the inclination in two directions with high accuracy and efficiency, with less interference and high sensitivity, and easy to downsize for two-way measurement. To provide a total.
The object of the second aspect of the present invention is to provide an inclinometer capable of measuring an inclination in one direction out of two directions without increasing the size and effectively preventing interference with another direction. Is to provide.
[0012]
The object of claim 3 according to the present invention is to be able to measure the inclination in one of the two directions with a smaller configuration, and more effectively prevent interference with other directions. It is to provide an inclinometer to obtain.
The object of the fourth aspect of the present invention is to provide an inclinometer capable of stably measuring the inclination in the other direction out of the two directions with a more compact configuration.
An object of claim 5 of the present invention is to provide an inclinometer that can stably perform inclination measurement in another direction of two directions with a further downsized configuration.
[0014]
[Means for Solving the Problems]
The inclinometer according to the present invention described in claim 1 is an inclinometer that is embedded in a measurement object and measures the inclination angle in order to achieve the above-described object.
A holding member;
A first weight having a substantially hollow cylindrical shape;
Each has a thin strip shape, is configured to be deformable by being attached with a strain gauge, and symmetrically with respect to the central axis on a first plane passing through the cylindrical central axis of the first weight. Arranged in pairs, each one end being coupled to the holding member, and each other end being coupled to a substantially annular upper end surface of the first weight, from the holding member to the first A pair of first strain plates for suspending weights;
A second weight;
A thin plate-like shape is formed so as to be able to bend and deform with a strain gauge attached thereto, and a second shape perpendicular to the first plane and the central axis on the cylindrical central axis of the first weight. The first weight is connected to the holding member and the other end is connected to the second weight, and the second weight is passed from the holding member through the hollow portion along the central axis of the first weight. A second strain plate that is suspended;
A case for housing the holding member, the first weight, the pair of first strain-generating plates, the second weight, and the second strain-generating plate;
It is characterized by comprising.
[0015]
The inclinometer according to the present invention described in claim 2 is:
The holding member has a protrusion that protrudes downward along the cylindrical central axis of the first weight, and the one end of the second strain plate is coupled to the protrusion. It is characterized by.
The inclinometer according to the present invention described in claim 3 is:
The second weight has a small-diameter portion extending upward along the cylindrical central axis of the first weight, and the other end of the second strain plate is coupled to the small-diameter portion. It is characterized by that.
[0016]
The inclinometer according to the present invention described in claim 4 is:
The first weight is characterized in that at least a lower part of a cylindrical outer peripheral surface is a tapered surface that expands upward in accordance with the operation range of the first weight to be regulated and the inner surface position of the case. .
The inclinometer according to the present invention described in claim 5 is:
In the first weight, at least a lower portion of the cylindrical inner peripheral surface is a tapered surface that extends downward in accordance with the operation range of the second weight to be regulated and the shape of the second weight. It is characterized by.
[0019]
[Action]
That is, the inclinometer according to claim 1 of the present invention is configured such that each of the first weights having a substantially hollow cylindrical shape is formed into a thin strip shape, and is provided with a strain gauge so that it can be flexibly deformed. On a first plane passing through the cylindrical central axis of the weight of the weight of the weight, and arranged symmetrically with respect to the central axis, each one end being coupled to the holding member and the other end being the first The first weight is suspended from the holding member by a pair of first strain plates that are respectively coupled to the upper end surface of the weight of one of the circular rings, and has a thin plate shape, and a strain gauge is attached. And one end coupled to the holding member on a cylindrical central axis of the first weight and along a second plane perpendicular to the first plane and the central axis. And a second strain plate connecting the other end to the second weight. And suspended from the second weight through the hollow portion along the center axis of the first spindle from the holding member, it is accommodated in the case.
With such a configuration, it is possible to measure the inclination in two directions with high accuracy and efficiency, with less interference, and high sensitivity, and it is easy to reduce the size.
[0020]
In the inclinometer according to claim 2 of the present invention, the holding member has a projecting portion projecting downward along the cylindrical central axis of the first weight, and the second strain plate. One end of the projection is coupled to the protrusion.
With such a configuration, in particular, tilt measurement in one of two directions can be performed without increasing the size, and interference with other directions can be effectively prevented.
In an inclinometer according to a third aspect of the present invention, the second weight has a small-diameter portion extending upward along the cylindrical central axis of the first weight, and the second strain plate The other end is coupled to the small diameter portion.
With such a configuration, in particular, tilt measurement in one of two directions can be performed with a smaller configuration, and interference with other directions can be more effectively prevented.
[0021]
The inclinometer according to claim 4 of the present invention is characterized in that the first weight has at least a lower part of the cylindrical outer peripheral surface in accordance with the operating range to be regulated by the first weight and the position of the inner surface of the case. The taper surface expands.
With such a configuration, it is possible to stably perform inclination measurement in the other direction out of the two directions with a more compact configuration.
In an inclinometer according to a fifth aspect of the present invention, the first weight has at least a lower part of a cylindrical inner peripheral surface in an operating range to be regulated by the second weight and a shape of the second weight. Accordingly, the taper surface extends downward.
With such a configuration, it is possible to stably perform inclination measurement in the other direction of the two directions with a further downsized configuration.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, based on an embodiment, an inclinometer of the present invention will be described in detail with reference to the drawings.
1 to 3 show the configuration of an inclinometer for two-direction measurement according to the first embodiment of the present invention. FIG. 1 is a perspective view of an entire inclinometer for two-direction measurement including an installation structure, FIG. 2 is a longitudinal sectional view of a single inclinometer for two-direction measurement, and FIG. 3 is an inclination for two-direction measurement. The perspective view inside the case of a meter is shown.
[0025]
The inclinometer shown in FIGS. 1 to 3 includes a holding member 1, first strain generating plates 2 </ b> A and 2 </ b> B, a first weight 3, a second strain generating plate 4, a second weight 5, a case 6, a first 1 and the second guide member 8, and FIG. 1 shows connecting rods 9 and 10 and a cable 11. Holding member 1, first strain plates 2A and 2B, first weight 3, second strain plate 4, second weight 5, case 6, first guide member 7, and second guide member 8 forms an inclinometer 20.
[0026]
The holding member 1 is formed into a short cylindrical shape using an insulating material, for example, and has a protruding portion 1a protruding downward on the central axis. Each of the first strain generating plates 2A and 2B forming a pair has a thin strip shape, and is symmetrical with respect to the central axis on both sides of the protruding portion 1a of the holding member 1 on a first plane passing through the central axis. Both are arranged parallel to the central axis (see FIG. 2). These first strain generating plates 2A and 2B have flexibility, and strain gauges (not shown) are attached to both surfaces or one surface by means of adhesion, vapor deposition, etc. The size can be measured. One end of each of the pair of first strain generating plates 2A and 2B is fixed to both sides of the protruding portion 1a on the lower surface of the holding member 1, and the other end is coupled to the upper surface of the first weight 3. Yes.
[0027]
The first weight 3 is formed in a hollow cylindrical shape whose both ends are open, and its upper end surface has a substantially annular shape with a stepped shape that is substantially semicircular at the upper end. The other ends of the first strain generating plates 2A and 2B paired with the stepped wall surface are coupled. That is, the other ends of the pair of first strain-generating plates 2A and 2B are fixed to the stepped wall surface of the first weight 3 by the fixing blocks 3a and 3b. Accordingly, the first weight 3 is suspended from the holding member 1 via the pair of first strain generating plates 2A and 2B.
[0028]
The second strain generating plate 4 is in the form of a thin strip plate, passes through the central axis and is on the tip surface of the protruding portion 1a of the holding member 1 on the second plane orthogonal to the first plane at the central axis. It is arranged below. The second strain generating plate 4 has flexibility, and strain gauges (not shown) are attached to both sides or one side thereof so that the magnitude of the bending deformation can be measured. It has become. One end of the second strain plate 4 is fixed to the lower surface of the protruding portion 1 a of the holding member 1, and the other end is coupled to the upper end of the second weight 5.
The second weight 5 is formed as a small diameter portion 5a extending upward in the columnar upper portion, and its upper end surface is circular, and the other end of the second strain plate 4 is coupled to the circular shape. ing. Therefore, the second weight 5 is also suspended from the holding member 1 via the second strain plate 4.
[0029]
The first weight 3 is formed at least on the outer peripheral portion of the lower end side portion with a tapered surface that expands upward (see FIG. 2) to ensure the movable range of the first weight 3 and to move the first weight 3 appropriately. The movable range is regulated so as not to exceed the range. Further, the first weight 3 is formed with a taper surface extending downward at least at the lower end side of the hollow portion along the central axis, and the movable range of the second weight 5 operating inside the first weight 3 is provided. In addition to ensuring, the movable range is regulated so as not to exceed the proper movable range.
The case 6 has, for example, a cylindrical shape with both ends closed, and includes the holding member 1, the first strain generating plates 2 </ b> A and 2 </ b> B, the first weight 3, the second strain generating plate 4, and the second weight 5. Accommodates each part. An electrically insulating coating is applied to the inner surface of the case 6. Note that damping oil or the like is enclosed in the case 6 in order to eliminate the influence of fine vibrations.
[0030]
The first guide member 7 is fixed to the upper end of the case 6, and in this case, a guide wing portion protruding in both sides in a plate shape along the second plane on which the second strain-generating plate 4 is disposed. 7a and 7b. The second guide member 8 is fixed to the lower end of the case 6, and in this case, a guide wing portion protruding in both sides in a plate shape along the second plane on which the second strain-generating plate 4 is disposed. 8a and 8b. These parts constitute an inclinometer 20 for measuring in two directions. The guide wings 7a and 7b of the first guide member 7 and the guide wings 8a and 8b of the second guide member 8 are guide pipes (not shown) that fit into the guide wings 8a and 8b when buried. It is provided to correctly set the orientation of the inclinometer 20 using a groove or a guide rail.
[0031]
For example, when the guide pipe is arranged in multiple stages, the guide wings 8a and 8b are fitted into guide grooves formed in the guide pipe vertically embedded in the measurement target, and a plurality of inclinometers 20 are provided one by one. The connecting rods 9 and 10 that define the interval of the inclinometer 20 are installed between the inclinometers 20. That is, the plurality of inclinometers 20 are connected to the guide wings 8a and 8b in the guide grooves of the guide pipe to maintain a predetermined posture, that is, a predetermined distance by the connecting rods 9 and 10 that define the mutual distance. And are inserted into the guide pipe sequentially and installed in multiple stages.
[0032]
The cable 11 transmits an electrical signal of a strain gauge attached to the first strain-generating plates 2A and 2B and the second strain-generating plate 4 of the inclinometer 20. The output electrical signals of the strain gauges attached to the first strain-generating plates 2A and 2B and the second strain-generating plate 4 of the inclinometer 20 are taken out to the outside via the cable 11, and each inclinometer 20 is It is used for the analysis of the inclination angle. Power supply to the first strain-generating plates 2A and 2B and the second strain-generating plate 4 of the inclinometer 20 is also performed via the cable 11.
[0033]
FIG. 4 shows a specific configuration example when the above-described inclinometer 20 is used for measuring the deformation of the excavation boundary surface in the earth retaining method.
The earth retaining method is a method for preventing collapse of surrounding ground due to excavation and inflow of groundwater from the excavated surface. In this earth retaining method, ground excavation is performed by placing a continuous earth retaining wall 21 on the excavation boundary surface in advance using a steel sheet pile or the like. The earth retaining wall 21 is provided in order to minimize the inclination and displacement generated in the existing building installed on the adjacent surrounding ground 22 due to excavation. Since the earth retaining wall 21 must be stably held during the excavation, the belly wall 23 and the cut edge 24 are sequentially provided, and the earth retaining wall 21 is provided at the step portion between the peripheral ground 22 and the excavated ground 25. support.
[0034]
Therefore, earth retaining measurement management accompanying information-oriented construction management is very important. The earth retaining wall 21 includes a steel pipe or a continuous wall made of reinforced concrete at a large depth in addition to those using steel sheet piles. The earth retaining measurement using the inclinometer 20 or the like is performed at the earth retaining wall 21 portion.
When the buried type inclinometer 20 is used for earth retaining measurement, for example, an aluminum guide pipe 26 is buried in the vicinity of the earth retaining wall 21 in the vertical direction up to the maximum measurement depth as shown in FIG. To do. As described above, a plurality of inclinometers 20 are inserted into the guide pipe 26 in multiple stages according to the required measurement depth while being connected by the connecting rod. Finally, the cement milk 27 is filled in the gap in the guide pipe 26 and hardened.
[0035]
When the ground excavation is started and the retaining wall 21 starts to be inclined and deformed toward the excavation side, the guide pipe 26 installed in the vicinity thereof is similarly deformed accordingly. The inclinometer 20 in the guide pipe 26 is inclined according to the deformation of the guide pipe 26 and detects the inclination of the earth retaining wall 21 at each depth. Based on the inclination angle and the distance between the inclinometers 20, the lateral displacement between each depth is calculated. The cumulative lateral displacement is obtained by sequentially adding the lateral displacement at the upper depth with the maximum depth point as the reference, that is, the fixed point, and the deformation of the entire retaining wall 21 can be confirmed based on the result. . In a large-scale earth retaining method or the like, measurement may be performed by directly burying the inclinometer 20 in a continuous wall made of reinforced concrete without using the guide pipe 26.
[0036]
The inclinometer 20 described above has the following characteristics.
The inclinometer 20 uses two sheets, that is, a pair of first strain-generating plates 2A and 2B as a strain-generating plate that suspends the first weight 3 and generates deflection according to the tilt angle. By disposing the gap on the plane, the moment force acting in the direction perpendicular to the bending direction of the first strain plates 2A and 2B is reduced. Also, by optimizing the shape of the first weight 3 as a taper shape that expands at least the lower end side of the outer surface upward with respect to the displacement in the bending direction, and limiting the movement range of the first weight 3 in the case 6, The first strain plates 2A and 2B are protected from overload. Furthermore, the second weight 5 is also optimized as a taper shape that extends downward at least on the lower end side of the inner surface of the first weight 3, and by limiting the movement range of the second weight 5 within the first weight 3, The second strain plate 4 is protected from overload.
[0037]
By configuring in this way, when an excessive inclination load is accidentally applied to the inclinometer 20, the detection part of the inclinometer 20 is protected, so that the reliability is improved and the handling becomes easy. Moreover, the inclinometer 20 has a short overall length of the movable part, optimizes the configuration of the movable part to improve space efficiency, and can reduce the outer diameter and the overall length including the case 6 of the inclinometer 20, so that Inclinometers can be installed in multiple stages.
[0038]
In the inclinometer 20 for measuring in two directions, for example, the first strain generating plates 2A and 2B and the second strain generating plate 4 used as the tilt detecting unit in the X-axis direction and the tilt detecting unit in the Y-axis direction. Each have a first weight 3 and a second weight 5 separately from each other, and the detection portions of each other are completely independent. In addition, in order to properly deform and allow strain gauges to detect strain efficiently, there is a limit to the dimension and shape of the strain generating plate, and the distance from the holding member 1 to the tip of the first weight 3 or the second weight 5 is limited. The distances determine the moving range of the first weight 3 or the second weight 5, respectively, so that the dimensions of the protruding portion 1a of the holding member 1, the small diameter portion 5a of the second weight 5, etc. are determined in consideration of them. To do.
[0039]
As described above, in the inclinometer 20 for measuring in two directions, the first strain generating plates 2A and 2B and the second strain generating plate 4 which are detection units in two directions are made independent, thereby eliminating mutual interference. Moreover, since the positions where the first strain generating plates 2A and 2B and the second strain generating plate 4 are installed can be easily brought close to each other in the depth direction, the measurement accuracy can be remarkably improved. Further, even if one of the inclination detectors mechanically fails, the other detector is not affected.
An electric insulator is used for the holding member 1 that holds the first and second strain generating plates 2A, 2B and the second strain generating piece 4, or an electrical insulating coating is provided on the surface thereof, and the case 6 By providing an electrically insulating coating on the inner surface and the surfaces of the weights 3 and 5, insulation between the electrical circuit portion such as the strain gauge portion of the inclinometer 20 and the outside of the case is performed, and the interior caused by a lightning surge or the like during a lightning strike The discharge is prevented.
The insulation treatment is desirably performed on all of the above-described members, but it is not always necessary to perform the insulation treatment on all of the members, and any one of the holding member 1, the case 6, and the mirrors 3 and 5 may be electrically connected. You may make it comprise an insulator or may provide insulation coating on the surface.
[0040]
Thus, the holding members 1 for holding the first strain generating plates 2A, 2B and the second strain generating plate 4 provided with strain gauges are made of an insulator, and the inner surface of the case 6 is provided with an insulating coating. Thus, it is difficult to generate a discharge in the inclinometer 20 due to a lightning surge voltage or the like, so that measurement accuracy and reliability are improved.
The experimental results of measuring the characteristics of the inclinometer 20 as described above will be described with reference to FIGS. The experiment was performed using a rated capacity having an inclination angle of -5 ° to 5 ° and a rated capacity having an inclination angle of -10 ° to 10 °.
[0041]
(1) Output characteristics
With respect to the rated capacity having an inclination angle of -5 ° to 5 ° and the rated capacity having an inclination angle of -10 ° to 10 °, the test results of nonlinearity and hysteresis in the configuration were as shown in FIG. . 5 (a) and 5 (b) show the output deviation in the X-axis direction and the output deviation in the Y-axis direction when the rated capacity has an inclination angle of −5 ° to 5 °, respectively. FIGS. 5C and 5D show the output deviation in the X-axis direction and the output deviation in the Y-axis direction when the rated capacity has an inclination angle of −10 ° to 10 °, respectively. 5 that the output deviation is within ± 0.5% RO.
[0042]
(2) Zero point temperature effect
FIG. 6 shows the test results of the zero point temperature effect measured without adding the tilt angle in the temperature compensation range of −10 ° C. to 60 ° C. FIGS. 6A and 6B show the change in output in the X-axis direction and the change in output in the Y-axis direction when the rated capacity has an inclination angle of −5 ° to 5 °, respectively. FIGS. 6C and 6D show the change in output in the X-axis direction and the change in output in the Y-axis direction when the rated capacity has an inclination angle of −10 ° to 10 °, respectively. In any of FIGS. 6A and 6B, the change amount of the zero point is within ± 1.5% RO with a change of ± 35 ° C., and is within ± 0.05% RO / ° C. of the scale value.
[0043]
(3) Output temperature effect
FIG. 7 shows the test result of the temperature influence of the output measured in the environment of −10 ° C., 25 ° C., and 60 ° C. FIG. 7 shows the change in output when the rated capacity is at an inclination angle of -5 ° to 5 °. In FIG. 7, the change in output is within ± 1.5% with a change of ± 35 ° C., and is within ± 0.1% / ° C. of the scale value.
(4) Long-term stability
FIG. 8 shows the results of a long-term stability test for 150 days or longer with the rated load applied in a temperature-controlled room. FIGS. 8A and 8B show the change in output in the X-axis direction and the change in output in the Y-axis direction when the rated capacity has an inclination angle of −5 ° to 5 °, respectively. In FIG. 8, the fluctuation range of the output is within ± 0.25% RO (150 days) at the maximum, and it can be seen that it has excellent long-term stability.
[0044]
(5) Lateral sensitivity ratio
FIG. 9 shows the results of measuring the amount of change in output when a load is applied in a direction perpendicular to the sensitivity direction. 9 (a) and 9 (b) show the output deviation due to a load perpendicular to the sensitivity direction and the rated capacity having an inclination angle of −10 ° to 10 °, respectively, with the rated capacity having an inclination angle of −5 ° to 5 °. It shows the output deviation due to the load perpendicular to the sensitivity direction. The lateral sensitivity ratio is about ± 0.2% RO with respect to the output in the sensitivity direction.
[0045]
(6) Arbitrary direction output in an inclined state
FIG. 10 shows the outputs of the X axis and the Y axis when the inclinometer 20 is tilted and rotated 360 ° around the central axis (Z axis) of the inclinometer 20. 10 (a) and 10 (b) show the output when the rated capacity is rotated at an inclination angle of −5 ° to 5 ° and the rated capacity is an inclination angle of −10 ° to 10 °, respectively. The output is shown when the object is rotated in an inclined state. In any case, the output along the theoretical sine wave can be confirmed.
[0046]
(7) Response time
Inclinometer 20 is filled with oil in case 6 in order to eliminate the influence of fine vibration. FIG. 11 shows the result of measuring the time until the output is stabilized by inclining the inclinometer 20 to the rated load quickly at room temperature. FIGS. 11A and 11B show the change in output in the X-axis direction and the change in output in the Y-axis direction when the rated capacity is at an inclination angle of −5 ° to 5 °, respectively. In FIG. 11, the output stabilizes in about 6 minutes for the X axis and about 3 minutes for the Y axis.
[0047]
FIG. 12 shows a configuration of an inclinometer for unidirectional measurement according to the second embodiment of the present invention.
FIG. 12 shows a longitudinal sectional view of a single clinometer for unidirectional measurement. The inclinometer of FIG. 12 removes the second strain plate 4 and the second weight 5 as one of the detection units from the inclinometer 20 for two-direction measurement shown in FIGS. The parts are the same as those shown in FIGS. 1 to 3 and are not described in detail.
An inclinometer 30 shown in FIG. 12 includes a holding member 1, strain generating plates 2A and 2B, a weight 3, a case 6 ′, a first guide member 7, and a second guide member 8, and further, FIG. Shows the cable 11.
[0048]
In this case, since the second strain generating plate 4 and the second weight 5 which are one detection part are removed from the inclinometer 20 for two-direction measurement shown in FIGS. The case 6 ', in particular, its entire length can be made short and highly sensitive.
In addition, this invention is not limited only to embodiment mentioned above, In the range included in the summary, various deformation | transformation can be implemented.
[0049]
【The invention's effect】
As described above, according to claim 1 of the present invention, each of the first weights having a substantially hollow cylindrical shape is formed into a thin strip shape, and a strain gauge is attached to be configured to be able to be flexibly deformed. The first weight is disposed symmetrically with respect to the central axis on a first plane passing through the cylindrical central axis of the first weight, and each end is coupled to the holding member and the other end. The first weight is suspended from the holding member by a pair of first strain plates that are respectively coupled to the upper end surface forming the annular shape of the first weight. Attached and configured to be able to bend and deform, and on the cylindrical central axis of the first weight and along a second plane orthogonal to the first plane and the central axis, one end is held as described above A second strain plate that is coupled to the member and has the other end coupled to the second weight. The second weight is suspended from the holding member through a hollow portion along the central axis of the first weight, and is accommodated in the case, so that the inclination in two directions can be performed with high accuracy and efficiency. It is possible to provide an inclinometer that can measure with high sensitivity with little interference and can be easily downsized.
[0050]
According to the inclinometer of claim 2 of the present invention, the holding member has a protruding portion that protrudes downward along the cylindrical central axis of the first weight, and the second strain plate. With the structure in which the one end is coupled to the projecting portion, it is possible to measure inclination in one of two directions without increasing the size, and effectively prevent interference with the other direction. Can do.
According to the inclinometer of claim 3 of the present invention, the second weight has a small-diameter portion extending upward along the cylindrical central axis of the first weight, and the second strain generation With the configuration in which the other end of the plate is coupled to the small-diameter portion, it is possible to measure the inclination in one of the two directions in a smaller configuration, and also to interfere with other directions. It can be prevented more effectively.
[0051]
According to the inclinometer of claim 4 of the present invention, the first weight has at least a lower portion of the cylindrical outer peripheral surface depending on the operation range to be regulated by the first weight and the position of the inner surface of the case. By using a tapered surface that expands upward, in particular, it is possible to stably measure the inclination in the other direction of the two directions with a more compact configuration.
According to the inclinometer of claim 5 of the present invention, the first weight has at least a lower portion of the cylindrical inner peripheral surface, the operating range to be regulated by the second weight, and the second weight. By using a tapered surface that expands downward depending on the shape, it is possible to stably measure the inclination in the other direction out of the two directions with a further miniaturized configuration.
[Brief description of the drawings]
FIG. 1 is a perspective view schematically showing a configuration of an inclinometer according to a first embodiment of the present invention with a part cut away.
2 is a longitudinal sectional view schematically showing the configuration of the inclinometer of FIG. 1. FIG.
3 is a perspective view schematically showing a configuration inside a case of the inclinometer of FIG. 1. FIG.
4 is a schematic perspective view for explaining an installation example of the inclinometer of FIG. 1; FIG.
FIG. 5 is a diagram showing an example of output characteristics by an experiment in the inclinometer of FIG. 1;
6 is a graph showing an example of temperature characteristics of a zero point by an experiment in the inclinometer of FIG. 1. FIG.
7 is a graph showing an example of temperature characteristics of an output by an experiment in the inclinometer of FIG. 1. FIG.
8 is a diagram showing an example of long-term stability by an experiment in the inclinometer of FIG. 1. FIG.
9 is a diagram showing an example of a lateral sensitivity ratio by an experiment in the inclinometer of FIG. 1. FIG.
10 is a diagram showing an example of an arbitrary direction output in an inclined state by an experiment in the inclinometer of FIG. 1;
11 is a diagram showing an example of response time characteristics by an experiment in the inclinometer of FIG. 1. FIG.
FIG. 12 is a longitudinal sectional view schematically showing a configuration of an inclinometer for unidirectional measurement according to a second embodiment of the present invention.
FIG. 13 is a perspective view schematically showing a configuration of a conventional inclinometer for two-way measurement.
[Explanation of symbols]
1 Holding member
1a Protrusion
2A, 2B First one and the other strain generating plate
3 First weight
3a, 3b fixed block
4 Second strain plate
5 Second weight
6,6 'case
7 First guide member
7a, 7b Guide wings
8 Second guide member
8a, 8b Guide wings
9,10 Connecting rod
11 Cable
20 Inclinometer
26 Guide pipe
27 Cement milk
30 Inclinometer

Claims

In an inclinometer that is embedded in the measurement object and measures the tilt angle,
A holding member;
A first weight having a substantially hollow cylindrical shape;
Each has a thin strip shape, is configured to be deformable by being attached with a strain gauge, and symmetrically with respect to the central axis on a first plane passing through the cylindrical central axis of the first weight. Arranged in pairs, each one end being coupled to the holding member, and each other end being coupled to a substantially annular upper end surface of the first weight, from the holding member to the first A pair of first strain plates for suspending weights;
A second weight;
A thin plate-like shape is formed so as to be able to bend and deform with a strain gauge attached thereto, and a second shape perpendicular to the first plane and the central axis on the cylindrical central axis of the first weight. The first weight is connected to the holding member and the other end is connected to the second weight, and the second weight is passed from the holding member through the hollow portion along the central axis of the first weight. A second strain plate that is suspended;
An inclinometer, comprising: the holding member, a first weight, a pair of first strain-generating plates, a second weight, and a case that houses the second strain-generating plate.

The holding member has a protruding portion that protrudes downward along the cylindrical central axis of the first weight, and the one end of the second strain plate is coupled to the protruding portion. The inclinometer according to claim 1.

The second weight has a small diameter portion extending upward along the cylindrical central axis of the first weight, and the other end of the second strain plate is coupled to the small diameter portion. The inclinometer according to claim 1 or 2, wherein

The first weight is characterized in that at least a lower portion of a cylindrical outer peripheral surface is a tapered surface that expands upward in accordance with the operation range of the first weight to be regulated and the position of the inner surface of the case. The inclinometer according to any one of claims 1 to 3.

In the first weight, at least a lower portion of the cylindrical inner peripheral surface is a tapered surface that extends downward in accordance with the operation range of the second weight to be regulated and the shape of the second weight. inclinometer according to any one of claims 1 to claim 4, characterized in.