JP4627533B2

JP4627533B2 - Underground displacement measuring device

Info

Publication number: JP4627533B2
Application number: JP2007020412A
Authority: JP
Inventors: 滋三輪; 薫小林; 智基塩谷; 幸樹熊谷; 琢之田村; 寿郎阿保
Original assignee: Tobishima Corp
Current assignee: Tobishima Corp
Priority date: 2007-01-31
Filing date: 2007-01-31
Publication date: 2011-02-09
Anticipated expiration: 2027-01-31
Also published as: JP2008185498A

Description

本発明は、所定地盤内の地中変位を計測する地中変位計測装置に関するものである。 The present invention relates to an underground displacement measuring apparatus that measures underground displacement within a predetermined ground.

一般に、地中変位計測装置とは、地盤地中内の変位・変動が予測される地中内に設置され、当該地盤の地表面や地表面近傍位置に設置した構造物などの隆起・変形を招来する地中変位量を計測する装置と指標されている。
ここで、従来、地中変位計測装置としては、地中の変位量を電気信号へ変換する計測装置、電気抵抗の変化から地中の伸縮量を計算する計測装置などいわゆる電気式計測装置が一般に知られている。 In general, an underground displacement measuring device is installed in the ground where displacement or fluctuation in the ground is predicted, and it is used to measure uplift / deformation of structures, etc. installed on the ground surface or in the vicinity of the ground surface. It is indexed as a device that measures the amount of underground displacement that is introduced.
Here, conventionally, as an underground displacement measuring device, a so-called electric measuring device such as a measuring device that converts an underground displacement amount into an electric signal, or a measuring device that calculates an underground expansion / contraction amount from a change in electric resistance is generally used. Are known.

しかし、このような従来の電気式計測装置では、以下の様な課題が生じていた。
すなわち、地中内変動が起きる地盤内では地下水位が高く、従来の電気式地中変位計測装置では、電線、その他金属部材で形成された計測装置構成部材の腐食、絶縁不良やショートなどが起こりやすく、もって計測装置の耐久性に限界が認められ、長期間の使用ができないとの課題があった。
また、複数個の電気式地中変位計測装置を同時に用いる際には、通常、電気信号の伝送を行うにつき、１個の地中変位計測装置で１本のケーブルが必要となるため、複数本の伝送用ケーブルを用意しなければならないこととなり、その結果、ケーブルの材料費と設置費用がきわめて高価になってしまうとの課題があった。
さらに、電気式の地中変位計測装置であると、電気信号が通常の状態で伝送できる距離は最大１km程度とされており、それ以上の距離の場合は増幅装置が必要となるので、この点からも機械費用や設置費用が割高になるとの課題があった。 However, such a conventional electric measuring apparatus has the following problems.
In other words, the groundwater level is high in the ground where subsurface fluctuations occur, and in conventional electric underground displacement measuring devices, corrosion, insulation failure, short-circuiting, etc. of measuring device components formed of electric wires and other metal members occur. There was a problem that the durability of the measuring device was limited, and that it could not be used for a long time.
In addition, when a plurality of electric underground displacement measuring devices are used at the same time, normally, one cable is required for one underground displacement measuring device to transmit an electrical signal. As a result, there has been a problem that the material cost and installation cost of the cable become extremely expensive.
Furthermore, in the case of an electrical underground displacement measuring device, the distance that electrical signals can be transmitted in a normal state is about 1 km at maximum, and an amplifier is required for distances longer than this, Therefore, there was a problem that the machine cost and the installation cost were expensive.

そこで近年、光ファイバセンサを利用した地中変位計測装置が開発されるに至った（特開２００４−１６３２９４号公報参照）。
しかして、この装置により従来の電気式地中変位計測装置の課題はほとんどが解決されるものとなった。 In recent years, therefore, an underground displacement measuring apparatus using an optical fiber sensor has been developed (see Japanese Patent Application Laid-Open No. 2004-163294).
As a result, most of the problems of the conventional electric underground displacement measuring apparatus have been solved by this apparatus.

すなわち、いわゆるＦＢＧ式光ファイバセンサを利用することにより、伝送信号の減衰が激しい電線を用いる必要がない。また、ＦＢＧ式光ファイバセンサは電気信号ではなく光信号を用いて計測を行うもので、単一の、すなわち１本の光ファイバケーブルで多数の地中計測装置を同時に接続し、計測可能となるため、伝送用光ケーブルの本数は伝送用電線に比較し圧倒的に少なくてすむものとなる。
さらに、光信号は長距離の伝送でも減衰が少なく、最大約９kmまで増幅装置を用いずに伝送可能とされる。 That is, by using a so-called FBG type optical fiber sensor, it is not necessary to use an electric wire in which the transmission signal is severely attenuated. In addition, the FBG type optical fiber sensor performs measurement using an optical signal instead of an electric signal, and a single, that is, a single optical fiber cable can be used to simultaneously connect a large number of underground measurement devices and perform measurement. Therefore, the number of transmission optical cables is far less than that of transmission wires.
Furthermore, optical signals are less attenuated even over long distance transmission, and can be transmitted up to about 9 km without using an amplifier.

特開２００４−１６３２９４号公報JP 2004-163294 A

かくして、本発明はいわゆるＦＢＧ式光ファイバセンサを利用した地中変位計測装置に、さらに改良を加え、品質を向上させたものであって、特に、地中内変動が起きる地盤内では地下水位が高く、耐水性の高い装置が要請されていることに応え開発されたものである。
すなわち、地下水位が高い地中内に設置した場合であっても、耐水性に優れているために長期間の使用にも耐え、しかも精度よく計測できる地中変位計測装置を提供することを目的とするものである。
Thus, the present invention is a further improvement to the underground displacement measuring device using the so-called FBG type optical fiber sensor to improve the quality, and in particular, the groundwater level in the ground where the underground fluctuation occurs. It was developed in response to the demand for high and water-resistant devices.
In other words, even when installed in the ground where the groundwater level is high, the object is to provide an underground displacement measuring device that can withstand long-term use and can measure with high accuracy due to its excellent water resistance. It is what.

本発明による地中変位計測装置は、
筒状収納部材と、前記筒状収納部材の上端部を閉塞する上端閉塞部と、筒状閉塞部の下端部を閉塞する下端閉塞部と、前記上端閉塞部及び前記下端閉塞部とにより上、下端部が閉塞され保護管とされた筒状収納部材に密閉状態で収納される計測部形成部と、を備え、
前記計測部形成部は、ＦＢＧによって構成された検出部と、該検出部が取り付けられると共に、検出された検出信号を伝送する1本の伝送用光ファイバケーブルと、前記検出部が取り付けられた伝送用光ファイバケーブルを被覆保護する被覆保護部と、前記被覆保護部の下端と前記下端閉塞部とを連結し、被覆保護部に張力を付加する張力付加部材と、を有し、
前記被覆保護部は、上、下の膨出部及び棒状被覆保護部を有する構成ユニットの1対を挟み合わせて内部を密閉状態となす構成とされ、少なくとも一方側の構成ユニットにおける前記上、下の膨出部及び棒状被覆保護部には、検出部つき伝送用光ファイバケーブルを導入、配置する導入溝が設けられ、上の膨出部における導入溝に沿って検出部つき伝送用光ファイバケーブルが導入されると共に、前記棒状被覆保護部における導入溝の略中間位置に前記検出部が配置され、下の膨出部において検出部つき伝送用光ファイバケーブルが折り返されて、棒状被覆保護部及び上の膨出部の導入溝に導入され、上の膨出部から外部へ向け退出させる構成とされ、
前記検出部つき伝送用光ファイバケーブルは、前記筒状収納部と前記被覆保護部とにより密閉、被覆され、外部から二重に遮断されてなり、
前記検出部が、地中の変化により伸縮してひずみを検出する際には、前記被覆保護部における棒状被覆保護部が該検出部と共に伸縮する構成とされた、
ことを特徴とし、
または、
筒状収納部材と、前記筒状収納部材の上端部を閉塞する上端閉塞部と、筒状閉塞部の下端部を閉塞する下端閉塞部と、前記上端閉塞部及び前記下端閉塞部とにより上、下端部が閉塞され保護管とされた筒状収納部材に密閉状態で収納される計測部形成部と、を備え、
前記計測部形成部は、ＦＢＧによって構成された検出部と、該検出部が取り付けられると共に、検出された検出信号を伝送する１本の伝送用光ファイバケーブルと、前記検出部が取り付けられた伝送用光ファイバケーブルを被覆保護する被覆保護部と、前記被覆保護部の下端と前記下端閉塞部とを連結し、被覆保護部に張力を付加する張力付加部材と、張力が付加されない伝送用光ファイバケーブル部分に設けられたＦＢＧよりなる温度検出部と、を有し、
前記被覆保護部は、上、下の膨出部及び棒状被覆保護部を有する構成ユニットの1対を挟み合わせて内部を密閉状態となす構成とされ、少なくとも一方側の構成ユニットにおける前記上、下の膨出部及び棒状被覆保護部には、検出部つき伝送用光ファイバケーブルを導入、配置する導入溝が設けられ、上の膨出部における導入溝に沿って検出部つき伝送用光ファイバケーブルが導入されると共に、前記棒状被覆保護部における導入溝の略中間位置に前記検出部が配置され、下の膨出部において検出部つき伝送用光ファイバケーブルが折り返されて、棒状被覆保護部及び上の膨出部の導入溝に導入され、上の膨出部から外部へ向け退出させる構成とされ、
前記検出部つき伝送用光ファイバケーブルは、前記筒状収納部と前記被覆保護部とにより密閉、被覆され、外部から二重に遮断され、
前記検出部が、地中の変化により伸縮してひずみを検出する際には、前記被覆保護部における棒状被覆保護部が該検出部と共に伸縮する構成とされた、
ことを特徴とし、
または、
合成樹脂製の筒状収納部材と、前記筒状収納部材の上端部を閉塞する合成樹脂製の上端閉塞部と、筒状閉塞部の下端部を閉塞する合成樹脂製の下端閉塞部と、前記上端閉塞部及び前記下端閉塞部とにより上、下端部が閉塞され保護管とされた筒状収納部材に密閉状態で収納される計測部形成部と、を備え、
前記計測部形成部は、ＦＢＧによって構成された検出部と、該検出部が取り付けられると共に、検出された検出信号を伝送する１本の伝送用光ファイバケーブルと、前記検出部が取り付けられた伝送用光ファイバケーブルを被覆保護する繊維強化プラスチック材製の被覆保護部と、前記被覆保護部の下端と前記下端閉塞部とを連結し、被覆保護部に張力を付加する繊維強化プラスチック材製の張力付加部材と、張力が付加されない伝送用光ファイバケーブル部分に設けられたＦＢＧよりなる温度検出部と、を有し、
前記被覆保護部は、上、下の膨出部及び棒状被覆保護部を有する構成ユニットの1対を挟み合わせて内部を密閉状態となす構成とされ、少なくとも一方側の構成ユニットにおける前記上、下の膨出部及び棒状被覆保護部には、検出部つき伝送用光ファイバケーブルを導入、配置する導入溝が設けられ、上の膨出部における導入溝に沿って検出部つき伝送用光ファイバケーブルが導入されると共に、前記棒状被覆保護部における導入溝の略中間位置に前記検出部が配置され、下の膨出部において検出部つき伝送用光ファイバケーブルが折り返されて、棒状被覆保護部及び上の膨出部の導入溝に導入され、上の膨出部から外部へ向け退出させる構成とされ、
前記検出部つき伝送用光ファイバケーブルは、前記筒状収納部と前記被覆保護部とにより密閉、被覆され、外部から二重に遮断され、
前記検出部が、地中の変化により伸縮してひずみを検出する際には、前記被覆保護部における棒状被覆保護部が該検出部と共に伸縮する構成とされた、
ことを特徴とし、
または、
前記筒状収納部材を長手方向に向かい複数個設置し、該複数個設置した筒状収納部材内の伝送用光ファイバケーブルを接続して構成した、
ことを特徴とし、
または、
前記筒状収納部材を並列に複数個設置し、該複数個設置した筒状収納部材内の伝送用光ファイバケーブルを接続して構成した、
ことを特徴とするものである。
The underground displacement measuring apparatus according to the present invention is
A cylindrical storage member, an upper end closing portion that closes an upper end portion of the cylindrical storage member, a lower end closing portion that closes a lower end portion of the cylindrical closing portion, and the upper end closing portion and the lower end closing portion, A measurement unit forming unit that is stored in a sealed state in a cylindrical storage member having a lower end closed and a protective tube ,
The measuring unit forming part includes a detection unit constituted by FBG, with detection portion is attached, one and the transmission optical fiber cable for transmitting a detection signal detected, the detection section is attached transmission A coating protection portion for coating and protecting the optical fiber cable, and a tension applying member for connecting the lower end of the coating protection portion and the lower end closing portion and applying tension to the coating protection portion,
The covering protection part is configured to sandwich a pair of constituent units having an upper and lower bulging part and a rod-like covering protecting part so that the inside is sealed, and the upper and lower parts in at least one of the constituent units The bulging part and the rod-shaped covering protection part are provided with an introduction groove for introducing and arranging a transmission optical fiber cable with a detection part, and the transmission optical fiber cable with a detection part along the introduction groove in the upper bulge part Is introduced, and the optical fiber cable for transmission with the detector is folded back at the lower bulging portion, and the rod-like sheath protector and It is introduced into the introduction groove of the upper bulging part, and is configured to exit outward from the upper bulging part,
The transmission optical fiber cable with the detection unit is hermetically sealed and covered by the cylindrical storage unit and the covering protection unit, and is double cut off from the outside.
When the detection unit detects strain by expanding and contracting due to a change in the ground, the rod-shaped coating protection unit in the coating protection unit is configured to expand and contract together with the detection unit.
It is characterized by
Or
A cylindrical storage member, an upper end closing portion that closes an upper end portion of the cylindrical storage member, a lower end closing portion that closes a lower end portion of the cylindrical closing portion, and the upper end closing portion and the lower end closing portion, A measurement unit forming unit that is stored in a sealed state in a cylindrical storage member having a lower end closed and a protective tube ,
The measuring unit forming part includes a detection unit constituted by FBG, with detection portion is attached, one and the transmission optical fiber cable for transmitting a detection signal detected, the detection section is attached transmission A coating protection part for coating and protecting the optical fiber cable, a tension applying member for connecting the lower end of the coating protection part and the lower end closing part, and applying tension to the coating protection part, and an optical fiber for transmission without applying tension A temperature detection unit made of FBG provided in the cable part ,
The covering protection part is configured to sandwich a pair of constituent units having an upper and lower bulging part and a rod-like covering protecting part so that the inside is sealed, and the upper and lower parts in at least one of the constituent units The bulging part and the rod-shaped covering protection part are provided with an introduction groove for introducing and arranging a transmission optical fiber cable with a detection part, and the transmission optical fiber cable with a detection part along the introduction groove in the upper bulge part Is introduced, and the optical fiber cable for transmission with the detector is folded back at the lower bulging portion, and the rod-like sheath protector and It is introduced into the introduction groove of the upper bulging part, and is configured to exit outward from the upper bulging part,
The optical fiber cable for transmission with the detection unit is hermetically sealed and covered by the cylindrical storage unit and the covering protection unit, and is double cut off from the outside,
When the detection unit detects strain by expanding and contracting due to a change in the ground, the rod-shaped coating protection unit in the coating protection unit is configured to expand and contract together with the detection unit.
It is characterized by
Or
A synthetic resin tubular housing member, and the cylindrical housing upper closed portion of synthetic resin for closing the upper end of the member, and the lower end closed portion of the synthetic resin for closing the lower end of the cylindrical closing part, the An upper end closing portion and a lower end closing portion, and a measurement portion forming portion that is housed in a sealed state in a cylindrical housing member that is closed at the lower end portion to form a protective tube ,
The measuring unit forming part includes a detection unit constituted by FBG, with detection portion is attached, one and the transmission optical fiber cable for transmitting a detection signal detected, the detection section is attached transmission a fiber-reinforced plastic material made of covering portions for covering and protecting the use optical fiber cables, said covering the lower end of the protective portion and connecting the said bottom closure portion, the tension of the manufactured fiber-reinforced plastic material for adding tension to the covering portion An additional member, and a temperature detection unit made of FBG provided in a transmission optical fiber cable portion to which no tension is applied,
The covering protection part is configured to sandwich a pair of constituent units having an upper and lower bulging part and a rod-like covering protecting part so that the inside is sealed, and the upper and lower parts in at least one of the constituent units The bulging part and the rod-shaped covering protection part are provided with an introduction groove for introducing and arranging a transmission optical fiber cable with a detection part, and the transmission optical fiber cable with a detection part along the introduction groove in the upper bulge part Is introduced, and the optical fiber cable for transmission with the detector is folded back at the lower bulging portion, and the rod-like sheath protector and It is introduced into the introduction groove of the upper bulging part, and is configured to exit outward from the upper bulging part,
The optical fiber cable for transmission with the detection unit is hermetically sealed and covered by the cylindrical storage unit and the covering protection unit, and is double cut off from the outside,
When the detection unit detects strain by expanding and contracting due to a change in the ground, the rod-shaped coating protection unit in the coating protection unit is configured to expand and contract together with the detection unit.
It is characterized by
Or
A plurality of the cylindrical storage members are installed facing in the longitudinal direction, and configured by connecting transmission optical fiber cables in the plurality of cylindrical storage members installed,
It is characterized by
Or
A plurality of the cylindrical storage members are installed in parallel, and configured by connecting transmission optical fiber cables in the plurality of cylindrical storage members installed,
It is characterized by this.

本発明による地中変位計測装置によれば、いわゆるＦＢＧ式光ファイバセンサを利用した地中変位計測装置にさらに改良を加え、特に、地中内変動が起きる地盤内では地下水位が高く、耐水性の高い装置が要請されるが、このような地下水位の高い箇所での計測であっても、充分に耐水性に優れているために長期間の使用にも耐えられ、しかも精度のよい計測ができるとの優れた効果を奏する。
According to the underground displacement measuring apparatus according to the present invention, the underground displacement measuring apparatus using the so-called FBG type optical fiber sensor is further improved. In particular, the groundwater level is high in the ground where underground changes occur, and the water resistance is high. However, even when measuring at such high groundwater levels, it is sufficiently water-resistant so that it can withstand long-term use and can be measured accurately. There is an excellent effect that can be done.

以下、本発明を図に示す発明を実施するための最良の形態に基づいて説明する。 Hereinafter, the present invention will be described based on the best mode for carrying out the invention shown in the drawings.

まず、図１から理解されるように、本発明による地中変位計測装置１は、筒状収納部材２と、前記筒状収納部材２の上端部を閉塞する上端閉塞部３と、筒状閉塞部２の下端部を閉塞する下端閉塞部４と、該筒状収納部材２に収納される計測部形成部５とを有して構成されている。 First, as understood from FIG. 1, the underground displacement measuring apparatus 1 according to the present invention includes a cylindrical storage member 2, an upper end closing portion 3 that closes an upper end portion of the cylindrical storage member 2, and a cylindrical closure. The lower end closing part 4 which closes the lower end part of the part 2 and the measurement part forming part 5 stored in the cylindrical storage member 2 are configured.

そして、前記計測部形成部５は、検出信号伝送用光ファイバケーブル７が１本用いられ、かつこの伝送用光ファイバケーブル７の所定箇所にはファイバグーティング（ＦＢＧ）２０により構成された検出部６が設けられている。
しかして、該検出部６つき伝送用光ファイバケーブル７は、前記筒状収納部材２内へ挿入されると共に、検出部６を内部へ設置した後、折り返されて外部へむけて退出する構成とされている。
そして、当該検出部６及び伝送用光ファイバケーブル７を被覆保護する被覆保護部８と、該被覆保護部８の下端と下端閉塞部４とを連結し、検出部６及び伝送用光ファイバケーブル７に一定の張力を付加する弾性係数の大きい張力付加部材９をも有している。 The measurement unit forming unit 5 uses a single detection signal transmission optical fiber cable 7, and a detection unit constituted by a fiber gouting (FBG) 20 at a predetermined position of the transmission optical fiber cable 7. 6 is provided.
Thus, the transmission optical fiber cable 7 with the detection unit 6 is inserted into the cylindrical housing member 2, and after the detection unit 6 is installed inside, the transmission optical fiber cable 7 is folded back and exits toward the outside. Has been.
Then, the covering protection portion 8 for covering and protecting the detection portion 6 and the transmission optical fiber cable 7 is connected to the lower end and the lower end closing portion 4 of the covering protection portion 8, and the detection portion 6 and the transmission optical fiber cable 7 are connected. A tension applying member 9 having a large elastic coefficient for applying a constant tension is also provided.

ここで、図１に示すように、筒状収納部材２は、塩化ビニル樹脂などの合成樹脂材で構成するとよい。該筒状収納部２は、内部に収納される検出部６や伝送用光ファイバケーブル７を地下水の浸水などから保護する保護管となるものだからである。 Here, as shown in FIG. 1, the cylindrical housing member 2 may be made of a synthetic resin material such as vinyl chloride resin. This is because the cylindrical housing portion 2 serves as a protective tube that protects the detection portion 6 and the transmission optical fiber cable 7 housed therein from the inundation of groundwater.

下端閉塞部４は、前記筒状収納部２の下端開口を塞ぐもので、図１から理解されるように、略栓状に形成されている。また、上端閉塞部３は前記筒状収納部２の上端開口を塞ぐよう略円盤状の形状になっている。 The lower end closing portion 4 closes the lower end opening of the cylindrical storage portion 2 and is formed in a substantially plug shape as understood from FIG. The upper end closing part 3 has a substantially disk shape so as to close the upper end opening of the cylindrical storage part 2.

これら上端閉塞部３及び下端閉塞部４についても筒状収納部２と同様に塩化ビニル樹脂などの合成樹脂材で構成するとよい。 The upper end closing portion 3 and the lower end closing portion 4 may be made of a synthetic resin material such as vinyl chloride resin, similarly to the cylindrical storage portion 2.

次に、被覆保護部８の構成につき、図１，図２，図３などを参照して説明すると、まず、該被覆保護部８は、２つの構成ユニット１０，１０を挟みあわせて、検出部６や伝送用の光ファイバケーブル７を外部から完全に遮蔽し被覆保護するように構成されている。この被覆保護部８の構成ユニット１０は、図から理解されるように、上下の膨出部とその中間の棒状被覆保護部とにより形成されており、前記の棒状被覆保護部内部に検出部６が配置される構成となっている。 Next, the configuration of the covering protection unit 8 will be described with reference to FIG. 1, FIG. 2, FIG. 3, and the like. First, the covering protection unit 8 sandwiches the two constituent units 10 and 10 and detects the detection unit. 6 and the optical fiber cable 7 for transmission are completely shielded from the outside and covered and protected. As can be understood from the drawing, the constituent unit 10 of the covering protection portion 8 is formed by upper and lower bulging portions and a bar-shaped covering protection portion in the middle thereof, and the detection portion 6 is provided inside the rod-shaped covering protection portion. Is arranged.

ここで、一方側の構成ユニット１０には検出部６つき伝送用光ファイバケーブル７を導入する導入溝１１が設けてある場合があり、該導入溝１１内に沿って検出部６つき光ファイバケーブル７を前記棒状被覆保護部に配置する。そして、その両端側は上下の膨出部によって被覆保護されると共に、挟み込まれて固定される。 Here, there is a case where an introduction groove 11 for introducing the transmission optical fiber cable 7 with the detection unit 6 is provided in the constituent unit 10 on the one side, and the optical fiber cable with the detection unit 6 along the introduction groove 11. 7 is arranged in the rod-shaped covering protection part. The both end sides are covered and protected by the upper and lower bulges, and are sandwiched and fixed.

この様に、検出部６つき光ファイバケーブル７が導入溝１１に沿って配設された前記一方側の構成ユニット１０には、図２に示すように他方側の構成ユニット１０が貼り付けられ、検出部６つき光ファイバケーブル７は挟み合わされて密閉状態とされ、完全に被覆保護されるものとなる。よって、地下水位の高い地中内にあっても、地下水の浸水を完全に防護でき、もって長期間の使用ができるものとされた。 In this way, to the one-side component unit 10 in which the optical fiber cable 7 with the detection unit 6 is disposed along the introduction groove 11, the other-side component unit 10 is attached as shown in FIG. The optical fiber cable 7 with the detection unit 6 is sandwiched and sealed to be completely covered and protected. Therefore, even in the ground where the groundwater level is high, the inundation of groundwater can be completely protected, and it can be used for a long time.

ここで、２つの構成ユニット１０，１０を貼り合わせて固定する方法については何ら限定されるものではないが、例えば、接着剤で接着するなど、両構成ユニット１０，１０を貼り合わせ固着し、密閉することが考えられる。 Here, the method of adhering and fixing the two constituent units 10 and 10 is not limited in any way. For example, the two constituent units 10 and 10 are bonded and fixed together by, for example, bonding with an adhesive. It is possible to do.

そして、前記被覆保護部８を繊維強化プラスチック（ＦＲＰ）で形成しておけば、該繊維強化プラスチック（ＦＲＰ）はきわめて耐水性が高い材質であり、もって密閉性もよく、たとえ地下水位の高い地中内で使用されたとしても、内部に浸水することがなく、長期間の使用に充分耐えうるものとなる。また、被覆保護部８の下端からは前記張力付加部材９が接続される。
この張力付加部材９としては、比較的弾性係数の大きい繊維強化プラスチック部材（ＦＲＰ）などで形成した棒状のコード部材が好ましい。そして、この張力付加部材９の下端を前記の下端閉塞部４に固着するものとなる。 And if the said covering protection part 8 is formed with fiber reinforced plastic (FRP), this fiber reinforced plastic (FRP) is a material with very high water resistance, and has good sealing property, even if the groundwater level is high. Even if it is used inside, it will not be submerged inside and will be able to withstand long-term use. Further, the tension applying member 9 is connected from the lower end of the covering protecting portion 8.
The tension applying member 9 is preferably a rod-shaped cord member formed of a fiber reinforced plastic member (FRP) having a relatively large elastic coefficient. Then, the lower end of the tension applying member 9 is fixed to the lower end closing part 4.

以上において次に、本発明による計測装置の組み立て及び設置につき説明する。
まず、検出部６つき光ファイバケーブル７を、被覆して保護する被覆保護部８を構成する構成ユニット１０の導入溝１１内に配置し、２つの構成ユニット１０，１０を貼り合わせ固着する。 Next, the assembly and installation of the measuring device according to the present invention will be described.
First, the detection unit 6 with the optical fiber cable 7, positioned within guide grooves 11 of the component units 10 constituting the covering portion 8 to cover and protect, bonding the two constituent units 10,10 fixed.

ここで、前記のように、検出部６は被覆保護部８の略中間位置に設置され、また被覆保護部８の先端側から挿入された伝送用光ファイバケーブル７は被覆保護部８の後端側に設けられた例えば円柱状の突起により構成された折り返し部１２で折り返し、再度前記被覆保護部８の先端側から退出するよう構成される。 Here, as described above, the detection unit 6 is installed at a substantially middle position of the coating protection unit 8, and the transmission optical fiber cable 7 inserted from the front end side of the coating protection unit 8 is the rear end of the coating protection unit 8. For example, it is configured to be folded back by a folded portion 12 constituted by, for example, a columnar protrusion provided on the side, and to be withdrawn from the front end side of the covering protection portion 8 again.

しかして、検出部６と伝送用光ファイバ７が配置された被覆保護部８は筒状収納部材２内に収納され、収納された被覆保護部８の後端側には、下端閉塞部４に接続された棒状の張力付加部材９が連結される。 Thus, the covering protection part 8 in which the detection part 6 and the transmission optical fiber 7 are arranged is housed in the cylindrical housing member 2, and the lower end closing part 4 is provided on the rear end side of the housed covering protection part 8. The connected rod-like tension applying members 9 are coupled.

その後、上端閉塞部３を上下に貫通するボルト部材１３を収納されている被覆保護部８の先端側に連結し、前記ボルト部材１３を螺合することにより、筒状収納部材２内において、一定の張力をもって被覆保護部８を配置する。 Thereafter, a bolt member 13 penetrating the upper end closing portion 3 in the vertical direction is connected to the distal end side of the covering protection portion 8 that is accommodated, and the bolt member 13 is screwed into the tubular housing member 2 so that it is constant. The covering protection part 8 is arranged with a tension of.

しかして、筒状収納部材２の内部は上端閉塞部３と下端閉塞部４とによって密閉されると共に、さらに、検出部６と伝送用光ファイバケーブル７とは被覆保護部８によって厳重に遮蔽、密閉され、もって地下水によって浸水するおそれが全くないものとなる。 Thus, the inside of the cylindrical housing member 2 is sealed by the upper end closing portion 3 and the lower end closing portion 4, and the detection portion 6 and the transmission optical fiber cable 7 are strictly shielded by the covering protection portion 8. It is hermetically sealed, so there is no risk of being submerged by groundwater.

このように組み立てられ、作成された地中変位計測装置１は、たとえば図５に示すような箇所の地中内に設置される。 The underground displacement measuring apparatus 1 assembled and created in this way is installed in the ground at a location as shown in FIG. 5, for example.

図５に示す地盤は、例えば変形しない堅牢な地盤部分１４と、その上に位置する塑性圧により隆起し、変質する地盤部分１５とよりなる。そして当該地盤は地下水位の高い地盤となっている。 The ground shown in FIG. 5 includes, for example, a solid ground portion 14 that does not deform, and a ground portion 15 that is raised and deformed by plastic pressure located thereon. The ground is a ground with a high groundwater level.

このような地盤上にトンネル２３などが形成された場合、地盤の隆起などの地中変位がダイレクトにインバート１６の隆起に直結する。よって、絶えず当該地盤の変位を計測し、監視する必要があるのである。 When the tunnel 23 or the like is formed on such ground, the underground displacement such as the ground uplift is directly connected to the uplift of the invert 16. Therefore, it is necessary to constantly measure and monitor the displacement of the ground.

そこで、トンネル２３のインバート１６を掘削し、この掘削孔に前記地中変位計測装置１を設置するのである。 Therefore, the invert 16 of the tunnel 23 is excavated, and the underground displacement measuring device 1 is installed in the excavation hole.

すると、被覆保護部８の上部膨出部と下部膨出部との中間位置に設置された棒状被覆保護部内の検出部６が、地中の変化により、例えば棒状被覆保護部と共に伸縮してひずみを生じ、該ひずみを検出することにより地中変位を計測することになる。
本発明では、検出部６の構成につき、図４に示すような、ファイバグレーティング型光ファイバセンサ、すなわちファイバグレーティング（ＦＢＧ）をセンサとして使用している、
ここで、ＦＢＧタイプのセンサ原理につき、若干説明しておく。 Then, the detection part 6 in the rod-shaped covering protection part installed in the middle position between the upper bulging part and the lower bulging part of the covering protecting part 8 expands and contracts together with, for example, the rod-shaped covering protecting part due to changes in the ground. The ground displacement is measured by detecting the strain.
In the present invention, a fiber grating type optical fiber sensor, that is, a fiber grating (FBG) as shown in FIG.
Here, the FBG type sensor principle will be briefly described.

まず、図４に示すように、光ファイバケーブル７のコア２１内に複数のブラッグ回折格子１７を形成する。
そして、ブラッグ回折格子１７に入射光１８が入射されると、ブラッグ回折格子１７の間隔ｘとコア２１の屈折率の積に比例する周波数を持つ反射光１９が発生する。 First, as shown in FIG. 4, a plurality of Bragg diffraction gratings 17 are formed in the core 21 of the optical fiber cable 7.
When the incident light 18 is incident on the Bragg diffraction grating 17, reflected light 19 having a frequency proportional to the product of the interval x of the Bragg diffraction grating 17 and the refractive index of the core 21 is generated.

しかして、光ファイバケーブル７にひずみが生じると、ブラッグ回析格子１７の間隔ｘが変化するため、反射光１９の周波数も変化する。そして、ファイバグレーティング（ＦＢＧ）２０を利用したセンサ、すなわちファイバグレーティングセンサは、この変化量をもとにひずみを計算するものとなる。 Thus, when the optical fiber cable 7 is distorted, the interval x of the Bragg diffraction grating 17 changes, and the frequency of the reflected light 19 also changes. A sensor using the fiber grating (FBG) 20, that is, a fiber grating sensor, calculates strain based on the amount of change.

ＦＢＧ、すなわちファイバグレーティング２０は光ファイバケーブル７のコア内ブラッグ回析格子１７を入射光１８を用いてＧｅドープ領域に形成されたもので、格子間隔ｘで決まる特定の波長λの光を反射する特徴を有する。 The FBG, that is, the fiber grating 20 is formed by forming the Bragg diffraction grating 17 in the core of the optical fiber cable 7 in the Ge-doped region using the incident light 18 and reflects light having a specific wavelength λ determined by the lattice spacing x. Has characteristics.

今、長さLの光ファイバケーブル７が張力を受けてΔLだけ伸張したとき、ひずみをεとして Now, when the optical fiber cable 7 of length L is stretched by ΔL under tension, the strain is ε

と定義し、ファイバグレーティング２０の格子間隔ｘも同じ比率でのびると仮定すれば、温度が一定のもとでは波長も同じ比率

で変化することとなる。
従って、反射光１９の波長を計測することでひずみεが得られることとなる。

Assuming that the grating spacing x of the fiber grating 20 also extends at the same ratio, the wavelength is the same ratio under a constant temperature.

Will change.
Therefore, the strain ε can be obtained by measuring the wavelength of the reflected light 19.

しかして、ファイバグレーティング２０を検出部６として構成すれば、その物体の歪みをファイバグレーティング２０の歪みとして検出することができるのである。 Therefore, if the fiber grating 20 is configured as the detection unit 6, the distortion of the object can be detected as the distortion of the fiber grating 20.

また、ファイバグレーティング２０の透過光２２は反射成分が欠落したスペクトルとなるので、欠落した波長を計測しても同様の計測が可能となる。 Further, since the transmitted light 22 of the fiber grating 20 has a spectrum with a missing reflection component, the same measurement is possible even if the missing wavelength is measured.

このように、ファイバグレーティング２０は、光ファイバケーブル７のコア２１内の屈折率を周期的に変化させたブラッグ回折格子１７を有して構成されており、該ファイバグレーティング波長選択性をひずみ測定に応用したものと言える。 As described above, the fiber grating 20 includes the Bragg diffraction grating 17 in which the refractive index in the core 21 of the optical fiber cable 7 is periodically changed. The fiber grating wavelength selectivity is used for strain measurement. It can be said that it has been applied.

また、ファイバグレーティング型光ファイバセンサの前記ファイバグレーティング２０には１mmあたり約２０００個のブラッグ回折格子１７が配置可能と言われているのである。 In addition, it is said that about 2000 Bragg diffraction gratings 17 can be arranged per 1 mm in the fiber grating 20 of the fiber grating type optical fiber sensor.

なお、図２に示すように、張力付加部材９によって張力が付加されない光ファイバケーブル部分、換言すれば被覆保護部８が伸縮しない部分、すなわち例えば、被覆保護部８の上方部分膨出部にファイバグレーティング（ＦＢＧ）２０よりなる温度検出部２４を設けておくことが考えられる。 As shown in FIG. 2, the optical fiber cable portion to which no tension is applied by the tension applying member 9, in other words, the portion where the covering protection portion 8 does not expand or contract, that is, for example, the fiber at the upper portion bulging portion of the covering protection portion 8. It is conceivable to provide a temperature detection unit 24 made of a grating (FBG) 20.

ファイバグレーティング（ＦＢＧ）２０は温度によっても変化するものであり、この温度検出部２４によって温度変化の部分のひずみだけ計測できれば、それを本来のひずみ計測値の補正に使用することができるからである。
また、本発明の様に光ファイバケーブル７を使用する計測装置の場合は、１本の光ファイバケーブル７の長さ方向各箇所に間隔をあけて複数の検出部６を装着し、該光ファイバケーブル７を複数個の筒状収納部材２内に直列状態にして長手方向に接続し、長尺な計測装置を構成すれば、地中内深い箇所から地表面まで複数層からなる地盤の変位をそれぞれの検出部６で計測できる装置とすることができる（図１０参照）。
さらに、図５に示すようなトンネル２３内において、その長手方向へ向け、所定間隔をあけた状態で本発明による計測装置を設置することもでき、もって精度の高い地中変位計測、監視ができるものとなる（図９参照）。 This is because the fiber grating (FBG) 20 changes depending on the temperature, and if the temperature detector 24 can measure only the strain of the temperature change portion, it can be used to correct the original strain measurement value. .
Further, in the case of a measuring device using the optical fiber cable 7 as in the present invention, a plurality of detection units 6 are mounted at intervals in the longitudinal direction of the single optical fiber cable 7, and the optical fiber is installed. If the cable 7 is connected in the longitudinal direction in a plurality of cylindrical storage members 2 and connected in the longitudinal direction to form a long measuring device, the displacement of the ground consisting of a plurality of layers from the deep underground to the ground surface can be achieved. It can be set as the apparatus which can be measured by each detection part 6 (refer FIG. 10).
Furthermore, in the tunnel 23 as shown in FIG. 5, the measuring device according to the present invention can be installed in a state with a predetermined interval in the longitudinal direction, so that the underground displacement can be measured and monitored with high accuracy. (See FIG. 9).

本発明による地中変位計測装置は、地中内の地下水位が高い箇所であって、供用中のトンネル２３の変状監視や変状が継続的に進行している供用中のトンネル２３におけるインバートの盤ぶくれ、さらには供用中のトンネル２３における側壁・アーチ部の変形の長期監視など計測箇所が坑口から離れており、長距離の信号伝送が必要な変状監視にきわめて有効である。
さらには、地中内の地下水位が高い箇所であって、遠隔地の地すべり斜面の防災監視、地すべり斜面と、信号を受信し地すべりを監視する場所が離れている場合の地すべり斜面の防災監視などにもきわめて有効なものとなる（図１１参照）。
The underground displacement measuring device according to the present invention is a place where the underground water level in the underground is high, and the inversion in the in-service tunnel 23 in which the in-service tunnel 23 is monitored for deformation and the deformation is continuously progressing. This is very effective for monitoring deformations that require long-distance signal transmission, such as long-term monitoring of deformation of side walls and arches in the tunnel 23 in service and long-term monitoring of deformation of the side walls and arches.
In addition, disaster prevention monitoring of landslide slopes in the ground where the groundwater level is high, disaster prevention monitoring of landslide slopes when the landslide slope and the place where signals are received and monitored are remote Is extremely effective (see FIG. 11).

本発明実施例の概略構成を説明する構成説明図（その１）である。BRIEF DESCRIPTION OF THE DRAWINGS It is structure explanatory drawing (the 1) explaining schematic structure of this invention Example. 本発明実施例の概略構成を説明する構成説明図（その２）である。FIG. 3 is a configuration explanatory diagram (part 2) illustrating a schematic configuration of an embodiment of the present invention. 本発明実施例の概略構成を説明する構成説明図（その３）である。FIG. 3 is a configuration explanatory diagram (part 3) illustrating a schematic configuration of an embodiment of the present invention. ファイバブラッググレーティングセンサの原理を説明する説明図である。It is explanatory drawing explaining the principle of a fiber Bragg grating sensor. 本発明の使用状態を説明する説明図である。It is explanatory drawing explaining the use condition of this invention. 本発明による計測装置の組み立て状態を説明する構成説明図（その１）である。It is composition explanatory drawing (the 1) explaining the assembly state of the measuring device by this invention. 本発明による計測装置の組み立て状態を説明する構成説明図（その２）である。It is composition explanatory drawing (the 2) explaining the assembly state of the measuring device by this invention. 本発明による計測装置の組み立て状態を説明する構成説明図（その３）である。It is composition explanatory drawing (the 3) explaining the assembly state of the measuring device by this invention. 本発明による計測装置の設置例を説明する説明図（その１）である。It is explanatory drawing (the 1) explaining the example of installation of the measuring device by this invention. 本発明による計測装置の設置例を説明する説明図（その２）である。It is explanatory drawing (the 2) explaining the example of installation of the measuring device by this invention. 本発明による計測装置の設置例を説明する説明図（その３）である。It is explanatory drawing (the 3) explaining the example of installation of the measuring device by this invention.

１地中変位計測装置
２筒状収納部
３上端閉塞部
４下端閉塞部
５計測部形成部
６検出部
７伝送用光ファイバケーブル
８被覆保護部
９張力付加部材
１０構成ユニット
１１導入溝
１２折り返し部
１３ボルト部材
１４変形しない堅牢な地盤部分
１５塑性圧により隆起し、変質する地盤
１６インバート
１７ブラッグ回析格子
１８入射光
１９反射光
２０ファイバグレーティング
２１コア
２２透過光
２３トンネル
２４温度検出部 DESCRIPTION OF SYMBOLS 1 Ground displacement measuring apparatus 2 Cylindrical storage part 3 Upper end obstruction | occlusion part 4 Lower end obstruction | occlusion part 5 Measurement part formation part 6 Detection part 7 Optical fiber cable for transmission 8 Cover protection part 9 Tension applying member 10 Configuration unit 11 Introducing groove 12 Folding part 13 Bolt member 14 Solid ground portion 15 not deformed Ground 16 raised and deformed by plastic pressure 16 Invert 17 Bragg diffraction grating 18 Incident light 19 Reflected light 20 Fiber grating 21 Core 22 Transmitted light 23 Tunnel 24 Temperature detector

Claims

A cylindrical storage member, an upper end closing portion that closes an upper end portion of the cylindrical storage member, a lower end closing portion that closes a lower end portion of the cylindrical closing portion, and the upper end closing portion and the lower end closing portion, A measurement unit forming unit that is stored in a sealed state in a cylindrical storage member having a lower end closed and a protective tube ,
The measuring unit forming part includes a detection unit constituted by FBG, with detection portion is attached, one and the transmission optical fiber cable for transmitting a detection signal detected, the detection section is attached transmission A coating protection portion for coating and protecting the optical fiber cable, and a tension applying member for connecting the lower end of the coating protection portion and the lower end closing portion and applying tension to the coating protection portion,
The covering protection part is configured to sandwich a pair of constituent units having an upper and lower bulging part and a rod-like covering protecting part so that the inside is sealed, and the upper and lower parts in at least one of the constituent units The bulging part and the rod-shaped covering protection part are provided with an introduction groove for introducing and arranging a transmission optical fiber cable with a detection part, and the transmission optical fiber cable with a detection part along the introduction groove in the upper bulge part Is introduced, and the optical fiber cable for transmission with the detector is folded back at the lower bulging portion, and the rod-like sheath protector and It is introduced into the introduction groove of the upper bulging part, and is configured to exit outward from the upper bulging part,
The transmission optical fiber cable with the detection unit is hermetically sealed and covered by the cylindrical storage unit and the covering protection unit, and is double cut off from the outside.
When the detection unit detects strain by expanding and contracting due to a change in the ground, the rod-shaped coating protection unit in the coating protection unit is configured to expand and contract together with the detection unit.
An underground displacement measuring device characterized by that.

A cylindrical storage member, an upper end closing portion that closes an upper end portion of the cylindrical storage member, a lower end closing portion that closes a lower end portion of the cylindrical closing portion, and the upper end closing portion and the lower end closing portion, A measurement unit forming unit that is stored in a sealed state in a cylindrical storage member having a lower end closed and a protective tube ,
The measuring unit forming part includes a detection unit constituted by FBG, with detection portion is attached, one and the transmission optical fiber cable for transmitting a detection signal detected, the detection section is attached transmission A coating protection part for coating and protecting the optical fiber cable, a tension applying member for connecting the lower end of the coating protection part and the lower end closing part, and applying tension to the coating protection part, and an optical fiber for transmission without applying tension A temperature detection unit made of FBG provided in the cable part ,
The covering protection part is configured to sandwich a pair of constituent units having an upper and lower bulging part and a rod-like covering protecting part so that the inside is sealed, and the upper and lower parts in at least one of the constituent units The bulging part and the rod-shaped covering protection part are provided with an introduction groove for introducing and arranging a transmission optical fiber cable with a detection part, and the transmission optical fiber cable with a detection part along the introduction groove in the upper bulge part Is introduced, and the optical fiber cable for transmission with the detector is folded back at the lower bulging portion, and the rod-like sheath protector and It is introduced into the introduction groove of the upper bulging part, and is configured to exit outward from the upper bulging part,
The optical fiber cable for transmission with the detection unit is hermetically sealed and covered by the cylindrical storage unit and the covering protection unit, and is double cut off from the outside,
When the detection unit detects strain by expanding and contracting due to a change in the ground, the rod-shaped coating protection unit in the coating protection unit is configured to expand and contract together with the detection unit.
An underground displacement measuring device characterized by that.

A synthetic resin tubular housing member, and the cylindrical housing upper closed portion of synthetic resin for closing the upper end of the member, and the lower end closed portion of the synthetic resin for closing the lower end of the cylindrical closing part, the An upper end closing portion and a lower end closing portion, and a measurement portion forming portion that is housed in a sealed state in a cylindrical housing member that is closed at the lower end portion to form a protective tube ,
The measuring unit forming part includes a detection unit constituted by FBG, with detection portion is attached, one and the transmission optical fiber cable for transmitting a detection signal detected, the detection section is attached transmission a fiber-reinforced plastic material made of covering portions for covering and protecting the use optical fiber cables, said covering the lower end of the protective portion and connecting the said bottom closure portion, the tension of the manufactured fiber-reinforced plastic material for adding tension to the covering portion An additional member, and a temperature detection unit made of FBG provided in a transmission optical fiber cable portion to which no tension is applied,
The covering protection part is configured to sandwich a pair of constituent units having an upper and lower bulging part and a rod-like covering protecting part so that the inside is sealed, and the upper and lower parts in at least one of the constituent units The bulging part and the rod-shaped covering protection part are provided with an introduction groove for introducing and arranging a transmission optical fiber cable with a detection part, and the transmission optical fiber cable with a detection part along the introduction groove in the upper bulge part Is introduced, and the optical fiber cable for transmission with the detector is folded back at the lower bulging portion, and the rod-like sheath protector and It is introduced into the introduction groove of the upper bulging part, and is configured to exit outward from the upper bulging part,
The optical fiber cable for transmission with the detection unit is hermetically sealed and covered by the cylindrical storage unit and the covering protection unit, and is double cut off from the outside,
When the detection unit detects strain by expanding and contracting due to a change in the ground, the rod-shaped coating protection unit in the coating protection unit is configured to expand and contract together with the detection unit.
An underground displacement measuring device characterized by that.

A plurality of the cylindrical storage members are installed facing in the longitudinal direction, and configured by connecting transmission optical fiber cables in the plurality of cylindrical storage members installed,
The underground displacement measuring device according to claim 1, claim 2, or claim 3 .

A plurality of the cylindrical storage members are installed in parallel, and configured by connecting transmission optical fiber cables in the plurality of cylindrical storage members installed,
The underground displacement measuring apparatus according to claim 1, 2, or 3.