JP2004293213A - Method for evaluating soundness of concrete pile - Google Patents

Method for evaluating soundness of concrete pile Download PDF

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Publication number
JP2004293213A
JP2004293213A JP2003088988A JP2003088988A JP2004293213A JP 2004293213 A JP2004293213 A JP 2004293213A JP 2003088988 A JP2003088988 A JP 2003088988A JP 2003088988 A JP2003088988 A JP 2003088988A JP 2004293213 A JP2004293213 A JP 2004293213A
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concrete pile
concrete
soundness
pile
elastic wave
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JP4050172B2 (en
Inventor
Yoshiaki Nagataki
慶明 長瀧
Nagamitsu Yagishita
修満 八木下
Masato Mashima
正人 真島
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Taisei Corp
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Taisei Corp
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  • Piles And Underground Anchors (AREA)
  • Length Measuring Devices Characterised By Use Of Acoustic Means (AREA)
  • Radar Systems Or Details Thereof (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for evaluating the soundness of a concrete pile, by which the soundness of the concrete pile can be evaluated accurately. <P>SOLUTION: A measuring hole 3 is formed at the central section of the concrete pile 1 and a hybrid type inspection device 5 composed of an elastic-wave radar 511 and an electromagnetic-wave radar 512 is hung down into the hole 3, and elastic waves and electromagnetic waves are transmitted in the horizontal direction from the inspection device 5. The elastic waves reflected by the external surface of the pile 1 and the electromagnetic waves reflected by a reinforcement 2 are detected by the device 5, and a first horizontal distance HD<SB>1</SB>from the inwall surface of the hole 3 to the external surface of the pile 1 is measured from a time data up to a detection after the oscillation of the elastic waves. A second horizontal distance HD<SB>2</SB>from the inwall surface of the hole 3 to the reinforcement 2 is measured from the time data up to a reception after the transmission of the electromagnetic waves, and the thickness of cover concrete of the reinforcement 2 is obtained from a difference between the distance HD<SB>1</SB>and the distance HD<SB>2</SB>and the soundness of the concrete pile 1 is evaluated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、既製杭や場所打ち杭等によって地中に構築された既存コンクリート杭あるいは新設コンクリート杭の健全性を評価する方法に関する。
【０００２】
【従来の技術】
既製杭や場所打ち杭等によって地中に構築された既存コンクリート杭の健全性を評価する方法として、地盤を掘削して既存コンクリート杭の頭部を露出させた後、その頭部を打撃して得られる反射波形から既存コンクリート杭の長さを測定して健全性を評価する方法が知られている。しかし、この方法では、既存コンクリート杭の長さが長い場合には正確な測定を行うことが困難であり、さらに既存コンクリート杭の長さ以外の寸法（例えば既存コンクリート杭の外径等）から既存コンクリート杭の健全性を評価することができないという問題があった。そこで、このような問題を解決するために、既存コンクリート杭の中心部に測定穴を鉛直に形成し、次いで測定穴に弾性波レーダを挿入した後、弾性波レーダから弾性波を水平方向に発振し、その反射波を弾性波レーダで検波することによって既存コンクリート杭の外径を測定する方法が提案されている（特許文献１参照）。
【０００３】
【特許文献１】
特開２００１−１５３６３８号公報
【０００４】
【発明が解決しようとする課題】
しかしながら、上記文献１に開示された方法では、既存コンクリート杭中に存在する鉄筋のコンクリート被り厚さ（既存コンクリート杭の外面から鉄筋までの水平距離）までは測定することができないため、既存コンクリート杭の健全性を正確に評価することが困難であった。
本発明は、このような問題点に着目してなされたものであり、既存コンクリート杭や新設コンクリートの健全性を正確に評価することのできるコンクリート杭の健全性評価方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
上記の目的を達成するために、請求項１の発明に係るコンクリート杭の健全性評価方法は、コンクリート杭に該コンクリート杭の軸方向に形成された測定穴から前記コンクリート杭の内部に電磁波レーダと弾性波レーダとからなるハイブリッド型探査装置を挿入し、次いで前記ハイブリッド型探査装置から弾性波を前記コンクリート杭の軸方向と直交する方向に発振して前記コンクリート杭の外面で反射した弾性波を前記ハイブリッド型探査装置で検波すると共に前記ハイブリッド型探査装置から電磁波を前記コンクリート杭の軸方向と直交する方向に発信して前記コンクリート杭の鉄筋で反射した電磁波を前記ハイブリッド型探査装置で受信し、前記弾性波を発振してから検波するまでの時間データに基づいて前記測定穴の内壁面から前記コンクリート杭の外面までの第１の距離を測定すると共に前記電磁波を発信してから受信するまでの時間データに基づいて前記測定穴の内壁面から前記鉄筋までの第２の距離を測定し、その測定結果から前記鉄筋のコンクリート被り厚さを求めて前記コンクリート杭の健全性を評価することを特徴とする。
【０００６】
請求項２の発明に係るコンクリート杭の健全性評価方法は、前記測定穴内で前記ハイブリッド型探査装置を鉛直な軸回りに回転させて前記コンクリート杭の健全性を評価することを特徴とする。
請求項１の発明では、測定穴に挿入されたハイブリッド型探査装置から弾性波をコンクリート杭の軸方向と直交する方向に発振してコンクリート杭の外面で反射した弾性波をハイブリッド型探査装置で検波すると共にハイブリッド型探査装置から電磁波をコンクリート杭の軸方向と直交する方向に発信してコンクリート杭の鉄筋で反射した電磁波をハイブリッド型探査装置で受信し、弾性波を発振してから検波するまでの時間データに基づいて測定穴の内壁面からコンクリート杭の外面までの第１の距離を測定すると共に電磁波を発信してから受信するまでの時間データに基づいて測定穴の内壁面から鉄筋までの第２の距離を測定することで、コンクリート杭中に存在する鉄筋のコンクリート被り厚さを測定することができる。したがって、鉄筋のコンクリート被り厚さからコンクリート杭の健全性を正確に評価することができる。
【０００７】
請求項２の発明では、前記測定穴に挿入された前記ハイブリッド型探査装置を前記コンクリート杭の軸回りに回転させることで、鉄筋のコンクリート被り厚さをコンクリート杭の全周に亘って測定できるので、コンクリート杭の健全性をより正確に評価することができる。
【０００８】
【発明の実施の形態】
以下、図面を参照して本発明の実施の形態について説明する。
図１は、本発明の一実施形態に係るコンクリート杭の健全性評価方法を実施するためのコンクリート被り厚さ測定システムの一例を示すブロック構成図である。同図に示されるコンクリート被り厚さ測定システムは、ハイブリッド型探査装置５と、このハイブリッド型探査装置５の上端に接続されたワイヤロープ６と、このワイヤロープ６を介してハイブリッド型探査装置５を昇降させる昇降装置７を備えており、昇降装置７には、ハイブリッド型探査装置５の昇降位置を検出する深度検出器８が付設されている。
【０００９】
また、図１のコンクリート被り厚さ測定システムはハイブリッド型探査装置５の出力からコンクリート杭の外径や鉄筋のコンクリート被り厚さ等を測定する測定装置９を備えており、この測定装置９で測定されたコンクリート杭の外径や鉄筋のコンクリート被り厚さは、表示装置１０に表示されるようになっている。
ハイブリッド型探査装置５は探査部５１と、探査部５１を鉛直な軸回りに駆動する回転装置５２を備えており、探査部５１は弾性波レーダ５１１と電磁波レーダ５１２とから構成されている。また、ハイブリッド型探査装置５は探査部５１の回転角度を検出する回転角度検出器５３を備えており、この回転角度検出器５３から出力された信号は、昇降装置７や回転装置５２を制御する制御装置１１に供給されるようになっている。なお、弾性波レーダ５１１は弾性波発振器５１１ａと弾性波検波器５１１ｂとから構成され、電磁波レーダ５１２は電磁波発信器５１２ａと電磁波受信器５１２ｂとから構成されている。
【００１０】
図２乃至図４は、本発明の一実施形態に係るコンクリート杭の健全性評価方法を示す図である。図２乃至図４において、符号１はコンクリート杭、２は鉄筋を示しており、コンクリート杭１の健全性を評価する場合には、図２に示すように、先ず、コンクリート杭１の中心部を鉛直に掘削して、コンクリート杭１の長さとほぼ同じ深さを有する測定穴３をコンクリート杭１の中心部に形成する。次に、図３に示すように、測定穴３の真上にウィンチ等の昇降装置７を設置し、昇降装置７を作動させてハイブリッド型探査装置５を測定穴３の中へワイヤロープ６で吊り降ろす。
【００１１】
このようにして、測定穴３の中に吊り降ろされたハイブリッド型探査装置５が所定位置に到達したならば、昇降装置７を停止させる。そして、図４に示すように、ハイブリッド型探査装置５の弾性波発振器５１１ａから弾性波（超音波を含む弾性波）ｅｗを水平方向に発振させるとともに、ハイブリッド型探査装置５の電磁波発信器５１２ａからコンクリートを透過可能な電磁波（例えば１ＧＨｚ未満の電磁波）ｍｇｗを水平方向に発信させる。また、これと同時にハイブリッド型探査装置５の回転装置５２を作動させ、ハイブリッド型探査装置５の探査部５１を鉛直な軸回りに一定速度で回転させる。
【００１２】
このとき、弾性波レーダ５１１の弾性波発振器５１１ａから発振された弾性波ｅｗは、コンクリート杭１のコンクリート中を伝播してコンクリート杭１の外面で反射される。そして、コンクリート杭１の外面で反射した弾性波ｅｗは弾性波レーダ５１１の弾性波検波器５１１ｂで検波され、この弾性波検波器５１１ｂでは、検波した弾性波をコンクリート杭１の半径情報として測定装置９に供給する。
【００１３】
一方、電磁波レーダ５１２の電磁波発信器５１２ａから発信された電磁波ｍｇｗは、コンクリート杭１のコンクリート中を伝播して鉄筋２で反射される。そして、鉄筋２で反射した電磁波ｍｇｗは電磁波レーダ５１２の電磁波受信器５１２ｂで受信され、この電磁波受信器５１２ｂでは、受信した電磁波は鉄筋２の位置情報として測定装置９に供給する。
【００１４】
測定装置９では、弾性波発振器５１１ａ及び弾性波検波器５１１ｂからの情報すなわち弾性波ｅｗを発振してから検波するまでの時間データに基づいて測定穴３の内壁面からコンクリート杭１の外面までの第１の水平距離ＨＤ１（図３参照）を測定するとともに、電磁波発信器５１２ａ及び電磁波受信器５１２ｂからの情報すなわち電磁波ｍｇｗを発信してから受信するまでの時間データに基づいて測定穴３の内壁面から鉄筋２までの第２の水平距離ＨＤ２（図３参照）を求める。そして、得られた第１の水平距離ＨＤ１と第２の水平距離ＨＤ２との差から鉄筋２のコンクリート被り厚さ（コンクリート杭１の外面から鉄筋２までの水平距離）を求め、これを表示装置１０に表示する。
【００１５】
このように、コンクリート杭１の中心部に測定穴３を鉛直に形成し、次いで測定穴３に弾性波レーダ５１１と電磁波レーダ５１２とを有するハイブリッド型探査装置５を降下させた後、ハイブリッド型探査装置５から弾性波ｅｗを水平方向に発振してコンクリート杭１の外面で反射した弾性波ｅｗをハイブリッド型探査装置５で検波すると共に、ハイブリッド型探査装置５から電磁波ｍｇｗを水平方向に発信してコンクリート杭１の鉄筋２で反射した電磁波ｍｇｗをハイブリッド型探査装置５で受信し、弾性波ｅｗを発振してから検波するまでの時間データに基づいて弾性波ｅｗを発振してから検波するまでの時間データに基づいて測定穴３の内壁面からコンクリート杭１の外面までの第１の水平距離ＨＤ１を測定するとともに、電磁波ｍｇｗを発信してから受信するまでの時間データに基づいて測定穴３の内壁面から鉄筋２までの第２の水平距離ＨＤ２を求めることにより、得られた第１の水平距離ＨＤ１と第２の水平距離ＨＤ２との差から鉄筋２のコンクリート被り厚さを測定することができる。したがって、コンクリート杭１中に存在する鉄筋２のコンクリート被り厚さからコンクリート杭１の健全性を正確に評価することができる。
【００１６】
また、測定穴３に降下されたハイブリッド型探査装置５を鉛直な軸回りに回転させることで、鉄筋２のコンクリート被り厚さをコンクリート杭１の全周に亘って測定できるので、コンクリート杭１の健全性をより正確に評価することができる。
なお、上述した実施形態ではコンクリート杭１が場所打ち杭で杭全体がコンクリートで充填されている場合を例示したが、コンクリート杭１が既製杭で杭中央部が土やソイルセメント等で充填されている場合でも本発明を適用できることは勿論である。また、上述した実施形態ではコンクリート杭１の横断面が円形である場合を例示したが、本発明はこれに限定されるものではなく、コンクリート杭１の横断面が矩形である場合にも鉄筋のコンクリート被り厚さを測定することができる。また、コンクリート杭１が大口径杭の場合にはコンクリート杭１の中心部に測定穴３を必ずしも設ける必要はなく、コンクリート杭１の外径部に近づいた位置に測定穴３を設けてもよい。さらに、コンクリート杭１に形成される測定穴３の数は１つに限られるものではなく、コンクリート杭１に複数の測定穴３を設けてもよい。
【００１７】
また、上述した実施形態では既存コンクリート杭の健全性を評価する場合を例示したが、本発明はこれに限定されるものではなく、新設コンクリート杭の健全性を評価する場合にも適用できることは勿論であり、この場合、測定穴３は新設コンクリート杭に予め設けておいてもよい。
【００１８】
【発明の効果】
以上説明したように、請求項１の発明に係るコンクリート杭の健全性評価方法によれば、コンクリート杭中に存在する鉄筋のコンクリート被り厚さを測定できるので、コンクリート杭の健全性を正確に評価することができる。
請求項２の発明に係るコンクリート杭の健全性評価方法によれば、鉄筋のコンクリート被り厚さをコンクリート杭の全周に亘って測定できるので、コンクリート杭の健全性をより正確に評価することができる。
【図面の簡単な説明】
【図１】コンクリート被り厚さ測定システムの一例を示すブロック構成図である。
【図２】コンクリート杭の中心部に測定穴を鉛直に形成した状態を示す図で、（ａ）は縦断面図、（ｂ）は（ａ）のＢ−Ｂ矢視断面図である。
【図３】測定穴にハイブリッド型探査装置を吊り降ろした状態を示す図である。
【図４】ハイブリッド型探査装置から発振された弾性波と電磁波を模式的に示す図である。
【符号の説明】
１ コンクリート杭
２ 鉄筋
３ 測定穴
５ ハイブリッド型探査装置
６ ワイヤロープ
７ 昇降装置
８ 深度検出器
９ 測定装置
１０ 表示装置
１１ 制御装置
５１ 探査部
５２ 回転装置
５３ 回転角度検出器
５１１ 弾性波レーダ
５１２ 電磁波レーダ
５１１ａ 弾性波発振器
５１１ｂ 弾性波検波器
５１２ａ 電磁波発信器
５１２ｂ 電磁波受信器[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for evaluating the soundness of an existing concrete pile or a newly constructed concrete pile constructed underground with a ready-made pile, a cast-in-place pile, or the like.
[0002]
[Prior art]
As a method to evaluate the soundness of existing concrete piles constructed underground with ready-made piles or cast-in-place piles, excavating the ground to expose the head of the existing concrete pile, and then hitting the head There is known a method of measuring the length of an existing concrete pile from the obtained reflection waveform to evaluate soundness. However, in this method, it is difficult to perform accurate measurement when the length of the existing concrete pile is long. There was a problem that the soundness of the concrete pile could not be evaluated. Therefore, to solve such a problem, a measurement hole is formed vertically in the center of the existing concrete pile, and then an elastic wave radar is inserted into the measurement hole, and then the elastic wave oscillates in the horizontal direction from the elastic wave radar. A method of measuring the outer diameter of an existing concrete pile by detecting the reflected wave with an elastic wave radar has been proposed (see Patent Document 1).
[0003]
[Patent Document 1]
JP 2001-153638 A
[Problems to be solved by the invention]
However, the method disclosed in the above-mentioned document 1 cannot measure the concrete covering thickness of the reinforcing steel existing in the existing concrete pile (horizontal distance from the outer surface of the existing concrete pile to the reinforcing steel). It has been difficult to accurately evaluate the soundness of the building.
The present invention has been made in view of such problems, and an object of the present invention is to provide a method for evaluating the soundness of concrete piles, which can accurately evaluate the soundness of existing concrete piles and new concrete. I do.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a method for evaluating the soundness of a concrete pile according to the invention of claim 1 includes an electromagnetic wave radar and a measuring hole formed in the concrete pile in an axial direction of the concrete pile. Insert a hybrid exploration device consisting of an elastic wave radar and then oscillate an elastic wave from the hybrid exploration device in a direction perpendicular to the axial direction of the concrete pile and reflect the elastic wave reflected on the outer surface of the concrete pile. The hybrid type exploration device detects and transmits electromagnetic waves from the hybrid type exploration device in a direction orthogonal to the axial direction of the concrete pile and receives the electromagnetic waves reflected by the reinforcing bars of the concrete pile by the hybrid type exploration device, From the inner wall surface of the measurement hole based on the time data from oscillation of the elastic wave to detection Measure a first distance to the outer surface of the concrete pile and measure a second distance from the inner wall surface of the measurement hole to the rebar based on time data from transmitting the electromagnetic wave to receiving the electromagnetic wave. The soundness of the concrete pile is evaluated by obtaining the concrete covering thickness of the reinforcing bar from the measurement results.
[0006]
The method for evaluating the soundness of a concrete pile according to the invention of claim 2 is characterized in that the soundness of the concrete pile is evaluated by rotating the hybrid exploration device around a vertical axis in the measurement hole.
According to the first aspect of the present invention, the elastic wave oscillated in the direction orthogonal to the axial direction of the concrete pile from the hybrid type exploration device inserted into the measurement hole, and the elastic wave reflected on the outer surface of the concrete pile is detected by the hybrid type exploration device. At the same time, the electromagnetic wave is transmitted from the hybrid exploration device in the direction orthogonal to the axial direction of the concrete pile, the electromagnetic wave reflected by the reinforcing bar of the concrete pile is received by the hybrid exploration device, and the elastic wave is oscillated and detected. The first distance from the inner wall surface of the measurement hole to the outer surface of the concrete pile is measured based on the time data, and the first distance from the inner wall surface of the measurement hole to the reinforcing bar is determined based on the time data from when the electromagnetic wave is transmitted to when it is received. By measuring the distance of No. 2, the concrete covering thickness of the reinforcing steel present in the concrete pile can be measured. Therefore, the soundness of the concrete pile can be accurately evaluated from the concrete covering thickness of the reinforcing bar.
[0007]
According to the invention of claim 2, since the hybrid type exploration device inserted into the measurement hole is rotated around the axis of the concrete pile, the concrete covering thickness of the reinforcing bar can be measured over the entire circumference of the concrete pile. Thus, the soundness of the concrete pile can be more accurately evaluated.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing an example of a concrete covering thickness measuring system for implementing a method for evaluating soundness of a concrete pile according to an embodiment of the present invention. The concrete covering thickness measuring system shown in the figure includes a hybrid exploration device 5, a wire rope 6 connected to the upper end of the hybrid exploration device 5, and a hybrid exploration device 5 via the wire rope 6. An elevating device 7 for elevating is provided, and the elevating device 7 is provided with a depth detector 8 for detecting an elevating position of the hybrid exploration device 5.
[0009]
Further, the concrete covering thickness measuring system of FIG. 1 includes a measuring device 9 for measuring the outer diameter of the concrete pile, the concrete covering thickness of the reinforcing steel, and the like from the output of the hybrid exploration device 5. The outer diameter of the concrete pile and the concrete covering thickness of the reinforcing bar are displayed on the display device 10.
The hybrid search device 5 includes a search unit 51 and a rotating device 52 that drives the search unit 51 about a vertical axis. The search unit 51 includes an elastic wave radar 511 and an electromagnetic wave radar 512. The hybrid search device 5 includes a rotation angle detector 53 that detects a rotation angle of the search unit 51, and a signal output from the rotation angle detector 53 controls the lifting device 7 and the rotation device 52. It is supplied to the control device 11. The elastic wave radar 511 includes an elastic wave oscillator 511a and an elastic wave detector 511b, and the electromagnetic wave radar 512 includes an electromagnetic wave transmitter 512a and an electromagnetic wave receiver 512b.
[0010]
2 to 4 are diagrams showing a method for evaluating the soundness of a concrete pile according to one embodiment of the present invention. 2 to 4, reference numeral 1 denotes a concrete pile, and 2 denotes a reinforcing bar. When soundness of the concrete pile 1 is evaluated, first, as shown in FIG. By drilling vertically, a measurement hole 3 having a depth substantially equal to the length of the concrete pile 1 is formed in the center of the concrete pile 1. Next, as shown in FIG. 3, an elevating device 7 such as a winch is installed just above the measuring hole 3, and the elevating device 7 is operated to move the hybrid-type exploration device 5 into the measuring hole 3 with a wire rope 6. Hang it down.
[0011]
When the hybrid-type exploration device 5 suspended in the measurement hole 3 reaches a predetermined position in this way, the lifting device 7 is stopped. Then, as shown in FIG. 4, an elastic wave (an elastic wave including an ultrasonic wave) ew is oscillated in a horizontal direction from an elastic wave oscillator 511 a of the hybrid exploration device 5, and an electromagnetic wave transmitter 512 a of the hybrid exploration device 5 transmits the elastic wave ew. An electromagnetic wave (eg, an electromagnetic wave of less than 1 GHz) mgw that can pass through concrete is transmitted in the horizontal direction. At the same time, the rotation device 52 of the hybrid search device 5 is operated to rotate the search unit 51 of the hybrid search device 5 about a vertical axis at a constant speed.
[0012]
At this time, the elastic wave ew oscillated from the elastic wave oscillator 511a of the elastic wave radar 511 propagates through the concrete of the concrete pile 1 and is reflected on the outer surface of the concrete pile 1. Then, the elastic wave ew reflected on the outer surface of the concrete pile 1 is detected by an elastic wave detector 511b of the elastic wave radar 511, and the elastic wave detector 511b uses the detected elastic wave as radius information of the concrete pile 1 as a measuring device. 9
[0013]
On the other hand, the electromagnetic wave mgw transmitted from the electromagnetic wave transmitter 512a of the electromagnetic wave radar 512 propagates through the concrete of the concrete pile 1 and is reflected by the reinforcing bar 2. Then, the electromagnetic wave mgw reflected by the reinforcing bar 2 is received by the electromagnetic wave receiver 512b of the electromagnetic wave radar 512, and the electromagnetic wave receiver 512b supplies the received electromagnetic wave to the measuring device 9 as position information of the reinforcing bar 2.
[0014]
In the measuring device 9, based on the information from the elastic wave oscillator 511 a and the elastic wave detector 511 b, that is, the time data from when the elastic wave ew is oscillated to when the elastic wave ew is detected, the measurement from the inner wall surface of the measuring hole 3 to the outer surface of the concrete pile 1 is performed. The first horizontal distance HD 1 (see FIG. 3) is measured, and the measurement hole 3 is measured based on the information from the electromagnetic wave transmitter 512a and the electromagnetic wave receiver 512b, that is, the time data from when the electromagnetic wave mgw is transmitted to when it is received. A second horizontal distance HD 2 (see FIG. 3) from the inner wall surface to the reinforcing bar 2 is obtained. Then, a first horizontal distance HD 1 and second horizontal distance difference thickness suffer concrete reinforcing bar 2 from of the HD 2 obtained (horizontal distance from the outer surface of the concrete pile 1 to rebar 2), this It is displayed on the display device 10.
[0015]
As described above, the measurement hole 3 is formed vertically in the center of the concrete pile 1, and then the hybrid type exploration device 5 having the elastic wave radar 511 and the electromagnetic wave radar 512 is dropped in the measurement hole 3, and then the hybrid type search is performed. The elastic wave ew is oscillated in the horizontal direction from the device 5, and the elastic wave ew reflected on the outer surface of the concrete pile 1 is detected by the hybrid exploration device 5, and the electromagnetic wave mgw is transmitted from the hybrid exploration device 5 in the horizontal direction. The electromagnetic wave mgw reflected by the reinforcing bar 2 of the concrete pile 1 is received by the hybrid exploration device 5, and the elastic wave ew is oscillated based on the time data from the time when the elastic wave ew is oscillated until the time when the elastic wave ew is detected. with measuring a first horizontal distance HD 1 to the outer surface of the concrete pile 1 from the inner wall surface of the measurement hole 3 on the basis of the time data, electromagnetic waves mg by obtaining the horizontal distance HD 2 times from the inner wall surface of the measuring hole 3 on the basis of the data up to rebar 2 second until receiving from the originating a w, a first horizontal distance HD 1 obtained first it is possible to measure the concrete wearing thickness of the reinforcing bar 2 from the difference between the second horizontal distance HD 2. Therefore, the soundness of the concrete pile 1 can be accurately evaluated from the concrete covering thickness of the reinforcing bar 2 existing in the concrete pile 1.
[0016]
In addition, by rotating the hybrid exploration device 5 lowered to the measurement hole 3 around a vertical axis, the concrete covering thickness of the reinforcing bar 2 can be measured over the entire circumference of the concrete pile 1. Soundness can be more accurately evaluated.
In the above embodiment, the concrete pile 1 is a cast-in-place pile and the entire pile is filled with concrete. However, the concrete pile 1 is a ready-made pile and the pile center is filled with soil or soil cement. It goes without saying that the present invention can be applied even in the case where it exists. Further, in the above-described embodiment, the case where the cross section of the concrete pile 1 is circular is illustrated. However, the present invention is not limited to this, and the reinforcing bar is not limited to the case where the cross section of the concrete pile 1 is rectangular. Concrete overlay thickness can be measured. When the concrete pile 1 is a large-diameter pile, it is not always necessary to provide the measurement hole 3 at the center of the concrete pile 1, and the measurement hole 3 may be provided at a position near the outer diameter of the concrete pile 1. . Further, the number of measurement holes 3 formed in the concrete pile 1 is not limited to one, and a plurality of measurement holes 3 may be provided in the concrete pile 1.
[0017]
Further, in the above-described embodiment, the case where the soundness of the existing concrete pile is evaluated is exemplified. However, the present invention is not limited to this. In this case, the measurement holes 3 may be provided in advance in the newly installed concrete pile.
[0018]
【The invention's effect】
As described above, according to the method for evaluating the soundness of a concrete pile according to the first aspect of the present invention, since the concrete covering thickness of the reinforcing steel present in the concrete pile can be measured, the soundness of the concrete pile can be accurately evaluated. can do.
According to the method for evaluating the soundness of a concrete pile according to the invention of claim 2, since the concrete covering thickness of the reinforcing bar can be measured over the entire circumference of the concrete pile, it is possible to more accurately evaluate the soundness of the concrete pile. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an example of a concrete covering thickness measuring system.
FIGS. 2A and 2B are diagrams showing a state in which a measurement hole is formed vertically in the center of a concrete pile, where FIG. 2A is a longitudinal sectional view and FIG. 2B is a sectional view taken along the line BB of FIG.
FIG. 3 is a diagram showing a state where a hybrid exploration device is suspended from a measurement hole.
FIG. 4 is a diagram schematically showing an elastic wave and an electromagnetic wave oscillated from a hybrid exploration apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Concrete pile 2 Reinforcing bar 3 Measurement hole 5 Hybrid exploration device 6 Wire rope 7 Elevation device 8 Depth detector 9 Measurement device 10 Display device 11 Control device 51 Exploration unit 52 Rotation device 53 Rotation angle detector 511 Elastic wave radar 512 Electromagnetic wave radar 511a elastic wave oscillator 511b elastic wave detector 512a electromagnetic wave transmitter 512b electromagnetic wave receiver

Claims (2)

コンクリート杭に該コンクリート杭の軸方向に形成された測定穴から前記コンクリート杭の内部に電磁波レーダと弾性波レーダとからなるハイブリッド型探査装置を挿入し、次いで前記ハイブリッド型探査装置から弾性波を前記コンクリート杭の軸方向と直交する方向に発振して前記コンクリート杭の外面で反射した弾性波を前記ハイブリッド型探査装置で検波すると共に前記ハイブリッド型探査装置から電磁波を前記コンクリート杭の軸方向と直交する方向に発信して前記コンクリート杭の鉄筋で反射した電磁波を前記ハイブリッド型探査装置で受信し、前記弾性波を発振してから検波するまでの時間データに基づいて前記測定穴の内壁面から前記コンクリート杭の外面までの第１の距離を測定すると共に前記電磁波を発信してから受信するまでの時間データに基づいて前記測定穴の内壁面から前記鉄筋までの第２の距離を測定し、その測定結果から前記鉄筋のコンクリート被り厚さを求めて前記コンクリート杭の健全性を評価することを特徴とするコンクリート杭の健全性評価方法。A hybrid exploration device comprising an electromagnetic wave radar and an elastic wave radar is inserted into the concrete pile from a measurement hole formed in the concrete pile in an axial direction of the concrete pile, and then the elastic wave is emitted from the hybrid type exploration device to the concrete pile. The elastic wave oscillating in the direction orthogonal to the axial direction of the concrete pile and reflected on the outer surface of the concrete pile is detected by the hybrid type exploration device, and the electromagnetic wave from the hybrid type exploration device is orthogonal to the axial direction of the concrete pile. The electromagnetic wave transmitted in the direction and reflected by the reinforcing bar of the concrete pile is received by the hybrid type exploration device, and the concrete is removed from the inner wall surface of the measurement hole based on time data from oscillation of the elastic wave to detection. Measuring a first distance to the outer surface of the pile and transmitting and receiving said electromagnetic waves; Measuring the second distance from the inner wall surface of the measurement hole to the reinforcing bar based on the time data up to, and determining the concrete covering thickness of the reinforcing bar from the measurement result to evaluate the soundness of the concrete pile. A method for evaluating the soundness of concrete piles, characterized by the following. 前記測定穴に挿入された前記ハイブリッド型探査装置を前記コンクリート杭の軸回りに回転させて前記コンクリート杭の健全性を評価することを特徴とする請求項１記載のコンクリート杭の健全性評価方法。The method for evaluating the soundness of a concrete pile according to claim 1, wherein the soundness of the concrete pile is evaluated by rotating the hybrid exploration device inserted into the measurement hole around an axis of the concrete pile.
JP2003088988A 2003-03-27 2003-03-27 Evaluation method for soundness of concrete piles Expired - Fee Related JP4050172B2 (en)

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