JP2020041994A - Underground displacement gauge and underground displacement calculation method - Google Patents

Underground displacement gauge and underground displacement calculation method Download PDF

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JP2020041994A
JP2020041994A JP2018171878A JP2018171878A JP2020041994A JP 2020041994 A JP2020041994 A JP 2020041994A JP 2018171878 A JP2018171878 A JP 2018171878A JP 2018171878 A JP2018171878 A JP 2018171878A JP 2020041994 A JP2020041994 A JP 2020041994A
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measurement
excavation
joint
underground displacement
displacement meter
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JP7246883B2 (en
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秀雄 木梨
Hideo Kinashi
秀雄 木梨
大輔 藤岡
Daisuke Fujioka
大輔 藤岡
雄一 岡崎
Yuichi Okazaki
雄一 岡崎
知 萩野
Satoru Hagino
知 萩野
幸治 辻村
Koji Tsujimura
幸治 辻村
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SK LABO CO Ltd
Obayashi Corp
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SK LABO CO Ltd
Obayashi Corp
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Abstract

To provide an underground displacement gauge and a natural ground displacement measurement method with which it is possible to measure a displacement in the horizontal and vertical directions occurring to a natural ground ahead of a pit face due to tunnel excavation at the same measurement point.SOLUTION: Provided is an underground displacement gauge for measuring an underground displacement and installed in a hole drilled in the underground, comprising: a plurality of long-sized members arranged in series; a plurality of joint members for connecting the adjacent long-sized members together; and two measurement units accommodated in the joint members and provided on plate surface with a strain causing plate in which a strain sensor is installed. The joint members include a pair of joint sleeves arranged in series and connected to the ends of the long-sized members and a hollow cylindrical substance arranged between the pair of joint sleeves and connected so as to be rotationally move in a direction in which the joint sleeves cross each other, with two of the measurement units installed inside of the hollow cylindrical substance in parallel across the pair of joint sleeves toward directions crossing the plate surface of the strain causing plate each other.SELECTED DRAWING: Figure 2

Description

本発明は、トンネル構築予定領域周辺の切羽前方における地山変位を計測する地中変位計および地中変位計を用いた地中変位算定方法に関する。   The present invention relates to an underground displacement meter for measuring a ground displacement in front of a face around a planned tunnel construction area and an underground displacement calculating method using the underground displacement meter.

従来より、地中にトンネル構造物を構築するべく掘削作業を行うと、トンネル構築予定領域の周辺地山にゆるみが生じて鉛直方向に変位が生じるだけでなく、トンネル軸線方向やトンネル横断方向等への水平変位も生じるなど、周辺地山に3次元的な影響を与えることが知られている。特に、軟弱な不良地山でのトンネル工事は、掘削時にも切羽崩落等の可能性があることから、切羽前方の先行変位を事前に計測することが重要となっている。   Conventionally, when excavation work is performed to construct a tunnel structure in the ground, not only does loosening occurs in the ground around the planned tunnel construction area, causing displacement in the vertical direction, but also in the tunnel axis direction and tunnel transverse direction, etc. It is known that a horizontal displacement to the surroundings also occurs, which has a three-dimensional effect on the surrounding ground. In particular, in tunnel construction on a weak defective mountain, it is important to measure the advance displacement in front of the face in advance because there is a possibility of face collapse during excavation.

このような中、トンネル掘削時における周辺地山の変位をモニタリング可能な計測機として、重力加速度センサ等を用いた傾斜計が広く知られている。この傾斜計は、トンネル軸方向に延在するボーリング孔を切羽前方の天端部に削孔し、このボーリング孔に設置されてトンネル掘削時における天端の沈下計測を行うものであり、地山の鉛直方向の変位を計測することはできるものの、水平方向の変位を計測することができない。   Under such circumstances, an inclinometer using a gravitational acceleration sensor or the like is widely known as a measuring instrument capable of monitoring the displacement of the surrounding ground at the time of tunnel excavation. This inclinometer drills a boring hole extending in the axial direction of the tunnel at the top end in front of the face, and is installed in this boring hole to measure settlement of the top end during tunnel excavation. Can measure the displacement in the vertical direction, but cannot measure the displacement in the horizontal direction.

一方、鉛直方向と水平方向の変位を計測可能な変位計として、リンク型変位計が知られている。リンク型変位計は、例えば特許文献1で開示されているように、地山の変位を感知する感知手段が内装された筒体と中継ロッドとを交互に接続してなり、これをトンネル工事周辺地盤に設置して、地盤の水平変位や鉛直変位を連続的に算定するものである。   On the other hand, a link-type displacement meter is known as a displacement meter capable of measuring vertical and horizontal displacements. As disclosed in Patent Document 1, for example, a link-type displacement meter is configured by alternately connecting a tubular body provided with sensing means for sensing the displacement of the ground and a relay rod, and connecting this to a tunnel construction area. It is installed on the ground and continuously calculates the horizontal displacement and vertical displacement of the ground.

特開2000−39316号公報JP 2000-39316 A

しかし、リンク型変位計は、水平方向の変位を計測する感知手段と鉛直方向の変位を計測する感知手段が、リンク型変位計の長手方向に位置をずらして設置されることから、水平変位と鉛直変位の計測値点が同一地点とならない。   However, the link-type displacement meter has a sensor for measuring the displacement in the horizontal direction and a sensor for measuring the displacement in the vertical direction. The measured points of vertical displacement are not the same point.

また、リンク型変位計はその断面径が大きく、広い設置空間を確保できる場合、例えば、既設トンネル内に敷設されている線路に対して支持部材を介して設置し、既設トンネル近傍の掘削工事に伴う地盤の緩みを計測するような場合に好適である。しかし、地山に設けたボーリング孔に挿入・設置して、地山の変位を測定する場合には、ボーリング孔を規格の大きい口径とせざるを得ず、適しているとはいえない。   In addition, when the link type displacement gauge has a large cross-sectional diameter and can secure a wide installation space, for example, it is installed via a support member on the track laid in the existing tunnel, and it is used for excavation work near the existing tunnel. It is suitable for measuring the accompanying ground slack. However, when measuring the displacement of the ground by inserting and installing it in the borehole provided in the ground, the borehole must have a large diameter, which is not suitable.

本発明は、かかる課題に鑑みなされたものであって、その主な目的は、トンネル掘削に伴い切羽前方の地山に生じる水平方向及び鉛直方向の変位を、同一の計測地点で計測することの可能な、地中変位計及び地山の変位計測方法を提供することである。   The present invention has been made in view of the above problems, and a main object of the present invention is to measure horizontal and vertical displacements generated in the ground in front of a face due to tunnel excavation at the same measurement point. It is an object of the present invention to provide an underground displacement meter and a method of measuring the displacement of the ground.

かかる目的を達成するため本発明の地中変位計は、地中に削孔された孔内に設置されて地中変位を計測する地中変位計であって、直列に配置される複数の長尺部材と、隣り合う該長尺部材どうしを連結する複数のジョイント部材と、該ジョイント部材に収納され、板面にひずみセンサが設置される起歪板を備える2体の計測部と、を備え、前記ジョイント部材が、直列に配置され、前記長尺部材の端部に接続される一対の継手スリーブと、一対の該継手スリーブ間に配置され、該継手スリーブが互いに直交する方向に回動自在となるように接続される中空筒体とを有し、該中空筒体の内側に2体の前記計測部が、前記起歪板の板面を互い直交する方向に向けて、一対の前記継手スリーブに跨って並列に設置されることを特徴とする。   In order to achieve such an object, an underground displacement meter of the present invention is an underground displacement meter that is installed in a hole drilled in the ground to measure an underground displacement, and includes a plurality of length-displacement devices arranged in series. A length member, a plurality of joint members connecting the adjacent long members, and two measurement units including a strain-generating plate housed in the joint member and having a strain sensor installed on a plate surface, The joint members are arranged in series, a pair of joint sleeves connected to the end of the long member, and disposed between the pair of joint sleeves, and the joint sleeves are rotatable in directions orthogonal to each other. A hollow cylindrical body connected so as to form a pair of the joints inside the hollow cylindrical body, wherein the two measurement units face the plate surfaces of the strain generating plate in directions perpendicular to each other. It is characterized by being installed in parallel across the sleeve.

本発明の地中変位計によれば、2体の計測部が並列に配置された状態で、それぞれの起歪板の板面を直交させてジョイント部材に収納されている。したがって、地中変位計を地中に設置する際に、起歪板の板面をそれぞれ鉛直方向及び水平方向に向けて配置することで、ジョイント部材の配置位置を計測地点とし、この計測地点で鉛直方向および水平方向の計測値の両者を取得できる。これにより、1つの計測地点で、鉛直方向および水平方向の計測値に基づく鉛直方向及び水平方向の地中変位の両者を算出することが可能となる。   According to the underground displacement meter of the present invention, in a state where the two measurement units are arranged in parallel, the respective strain plates are housed in the joint member with the plate surfaces orthogonal to each other. Therefore, when installing the underground displacement meter in the ground, by arranging the plate surface of the strain plate in the vertical direction and the horizontal direction, respectively, the arrangement position of the joint member is set as a measurement point, and at this measurement point Both vertical and horizontal measurements can be obtained. Accordingly, it is possible to calculate both the vertical and horizontal displacements under the ground based on the measured values in the vertical and horizontal directions at one measurement point.

本発明の地中変位計は、前記計測部が、記起歪板の一端を一方の前記継手スリーブに固定する固定具と、他端を他方の前記継手スリーブに対して前記板面と平行な方向に摺動自在に押圧する押圧具と、を備えることを特徴とする。   In the underground displacement meter of the present invention, the measuring unit has a fixture for fixing one end of the strain plate to one of the joint sleeves, and the other end is parallel to the plate surface with respect to the other joint sleeve. And a pressing tool that slidably presses in a direction.

本発明の地中変位計によれば、一対の継手スリーブが何れに回動しても、前記起歪板は、ひずみセンサが設置される板面と直交する方向にのみ変形するため、2体の計測部各々で計測したい方向の変位を精度よく計測することが可能となる。   According to the underground displacement meter of the present invention, the strain generating plate is deformed only in a direction orthogonal to the plate surface on which the strain sensor is installed, regardless of which one of the pair of joint sleeves is rotated. It is possible to accurately measure the displacement in the direction desired to be measured by each of the measuring units.

本発明の地中変位計は、前記ジョイント部材に、前記継手スリーブと前記長尺部材との間に配置されて両者を接続する金具本体と、該金具本体の外面に先端を前記孔の孔壁に向けて放射状に設置される複数の支持棒材と、を有する連結金具を一対備え、前記支持棒材は、長手方向に伸縮する弾性棒材を1本含む少なくとも3本以上設置されることを特徴とする。   The underground displacement meter of the present invention includes a metal fitting main body disposed between the joint sleeve and the long member and connecting the joint member to the joint member; And a plurality of support fittings radially installed toward the support member, wherein the support fittings are provided with at least three or more elastic sticks including one elastic stick that expands and contracts in the longitudinal direction. Features.

本発明の地中変位計によれば、ボーリング孔内において、複数の支持棒材のうち弾性棒材を収縮した状態で鉛直上向きに配置し、他の支持棒材で地中変位計を支持するように設置すると、弾性棒材は常時、鉛直上方の孔壁を押圧するとともに、その反力での他の支持棒材も孔壁を押圧する態様となる。これにより、周辺地山に変形が生じた際にも地中変位計はボーリング孔内で位置ズレ等を生じることがなく、周辺地山の挙動に追従して隣り合う長尺部材間の角度をジョイント部材を介して変化させることが可能となる。   According to the underground displacement meter of the present invention, in the borehole, the elastic bar among the plurality of support bars is arranged vertically upward in a contracted state, and the underground displacement meter is supported by another support bar. With such a configuration, the elastic bar always presses the hole wall vertically above, and the other support bar presses the hole wall by the reaction force. As a result, even when deformation occurs in the surrounding ground, the underground displacement meter does not generate a displacement or the like in the boring hole, and follows the behavior of the surrounding ground to adjust the angle between the adjacent long members. It can be changed via the joint member.

本発明の地中変位計測方法は、トンネル構築予定領域の周辺地山に請求項1または2に記載の地中変位計を、切羽近傍からトンネル掘進方向に延在する削孔に挿入するとともに、2体の前記計測部各々の前記起歪板が板面をそれぞれ鉛直方向および水平方向に向くようにして設置した後、最も坑口側に位置する前記長尺部材の坑口側端部を計測補助地点、複数の前記ジョイント部材の配置位置を計測地点として設定し、掘削開始前および掘削を開始し切羽位置が所定の距離だけ進むごとに複数の前記計測地点各々で計測を行い、掘削開始前および掘削開始後に計測を行った各時点における前記計測地点各々の位置座標を、前記計測補助地点の位置座標を基準とし、複数の前記計測地点で得た計測値のうちの自己よりも坑口側に位置する前記計測地点の計測値に基づいて算定し、複数の前記計測地点各々における掘削前後の位置座標の変位を、鉛直方向および水平方向各々で算定することを特徴とする。   The underground displacement measuring method of the present invention inserts the underground displacement meter according to claim 1 or 2 into a ground around a planned tunnel construction area into a hole extending from the vicinity of a face in the tunnel excavation direction, After the strain plates of each of the two measurement units are installed so that the plate surfaces face the vertical direction and the horizontal direction, respectively, the pit-side end of the long member located closest to the pit side is a measurement auxiliary point. Setting the arrangement positions of the plurality of joint members as measurement points, performing measurement at each of the plurality of measurement points before the start of excavation and each time the excavation is started and the face position advances by a predetermined distance, and before the start of excavation and excavation The position coordinates of each of the measurement points at each time point when the measurement was performed after the start, based on the position coordinates of the measurement auxiliary point, are located on the wellhead side of the measurement values obtained at the plurality of measurement points. The meter Calculated based on the measurement values of a point, a displacement of position coordinates before and after drilling of the plurality of the measurement point, respectively, characterized in that to calculate the vertical and horizontal directions, respectively.

本発明の地中変位計測方法によれば、地中に削孔した孔内に地中変位計を、2体の計測部に備える起歪板の板面がそれぞれ鉛直方向および水平方向を向くように設置するのみの簡略な設置方法で、多大な手間を要することなく、複数の計測地点各々で、トンネル掘削に伴い切羽前方の地山に生じる水平方向及び鉛直方向の変位の両者を算定することが可能となる。   According to the underground displacement measuring method of the present invention, the underground displacement meter is provided in the hole drilled in the ground so that the plate surfaces of the strain plates provided in the two measurement units face the vertical direction and the horizontal direction, respectively. Calculate both horizontal and vertical displacements occurring at the ground in front of the face due to tunnel excavation at each of multiple measurement points with a simple installation method that only requires installation at Becomes possible.

また、本発明の地中変位計測方法は、トンネル構築予定領域の周辺地山に請求項1または2に記載の地中変位計を、切羽近傍からトンネル掘進方向に延在する削孔に挿入するとともに、2体の前記計測部各々の前記起歪板が板面をそれぞれ鉛直方向および水平方向に向くようにして設置した後、最も坑口側に位置する前記長尺部材の坑口側端部を計測補助地点、複数の前記ジョイント部材の配置位置を計測地点として設定し、掘削開始前および掘削を開始し切羽位置が所定の距離だけ進むごとに複数の前記計測地点各々で計測を行い、掘削開始前における前記計測地点各々の位置座標を、前記計測補助地点の位置座標を基準とし、複数の前記計測地点で得た計測値のうちの自己よりも坑口側に位置する前記計測地点の計測値に基づいて算定し、掘削開始後に計測を行った各時点における前記計測地点各々の位置座標を、掘削前に算定した前記地中変位計の最も先端側に位置する計測地点の位置座標を基準とし、複数の前記計測地点で得た計測値のうちの自己よりも先端側に位置する前記計測地点の計測値に基づいて算定し、複数の前記計測地点各々における掘削前後の位置座標の変位を、鉛直方向および水平方向各々で算定することを特徴とする。   According to the method of measuring the underground displacement of the present invention, the underground displacement meter according to claim 1 or 2 is inserted into a drilling hole extending in the tunnel excavation direction from the vicinity of the cutting face in the ground around the planned tunnel construction area. At the same time, after setting the strain plates of each of the two measurement units so that the plate surfaces face the vertical direction and the horizontal direction, respectively, measure the pit-side end of the long member located closest to the pit side Auxiliary points, the arrangement positions of the plurality of joint members are set as measurement points, measurement is performed at each of the plurality of measurement points before the start of excavation and whenever excavation is started and the face position advances by a predetermined distance, and before the start of excavation. The position coordinates of each of the measurement points are based on the position coordinates of the measurement auxiliary point, and are based on the measurement values of the measurement points located on the wellhead side of the self among the measurement values obtained at the plurality of measurement points. Calculated The position coordinates of each of the measurement points at each time point when the measurement was performed after the start of excavation, based on the position coordinates of the measurement point located at the most distal end side of the underground displacement meter calculated before excavation, a plurality of the measurement points Calculated based on the measurement value of the measurement point located on the tip side than the self of the measurement values obtained in, the displacement of the position coordinates before and after excavation at each of the plurality of measurement points, each in the vertical and horizontal directions It is characterized by being calculated by.

本発明の地中変位計測方法によれば、掘削開始後の各計測地点の地山変位を、掘削作業による影響を受ける程度が最も小さい計測地点の位置座標を基準に算定することから、掘削に伴うトンネル周辺地山の挙動をより精度よく把握することが可能となる。   According to the underground displacement measurement method of the present invention, the ground displacement at each measurement point after the start of excavation is calculated based on the position coordinates of the measurement point that is least affected by the excavation work. This makes it possible to more accurately grasp the behavior of the ground around the tunnel.

本発明によれば、地中に削孔した孔内に地中変位計を、2体の計測部各々に備える起歪板の板面がそれぞれ鉛直方向および水平方向を向くようにして設置することにより、複数の計測地点各々で、トンネル掘削に伴い切羽前方の地山に生じる水平方向及び鉛直方向の変位の両者を把握することが可能となる。   According to the present invention, an underground displacement meter is installed in a hole drilled in the ground such that the plate surfaces of the strain generating plates provided in each of the two measurement units face the vertical direction and the horizontal direction, respectively. Thereby, at each of the plurality of measurement points, it is possible to grasp both the horizontal and vertical displacements that occur in the ground in front of the face due to tunnel excavation.

本実施の形態における地中変位計の設置状況を示す平面図である。It is a top view which shows the installation situation of the underground displacement meter in this Embodiment. 本実施の形態における地中変位計の詳細を示す平面図である。It is a top view which shows the detail of the underground displacement meter in this Embodiment. 本実施の形態における地中変位計の計測部の詳細を示す図である。It is a figure showing the details of the measurement part of the underground displacement meter in this embodiment. 本実施の形態における地中変位計に水平方向の外力が作用した状態を示す平面図である。FIG. 4 is a plan view showing a state in which a horizontal external force acts on the underground displacement meter in the present embodiment. 本実施の形態における地中変位を算出する際の座標軸を示す図である。It is a figure showing the coordinate axis at the time of calculating underground displacement in this embodiment. 本実施の形態における計測地点の位置および計測部により計測される角度を示す概念図である。FIG. 3 is a conceptual diagram illustrating a position of a measurement point and an angle measured by a measurement unit according to the present embodiment. 本実施の形態における第1の算定方法により算定した計測地点の位置座標を示す図である。It is a figure showing the position coordinate of the measurement point calculated by the 1st calculation method in this embodiment. 本実施の形態における第2の算定方法により算定した計測地点の位置座標を示す図である。It is a figure showing the position coordinate of the measurement point calculated by the 2nd calculation method in this embodiment. 本実施の形態における地中変位計に備える計測部の配置例を示す図である。It is a figure showing an example of arrangement of a measuring part with which an underground displacement meter in this embodiment is provided. 本実施の形態における地中変位計に備える計測部の他の事例を示す図である。It is a figure which shows the other example of the measurement part with which the underground displacement meter in this Embodiment is provided.

本発明は、トンネルの掘削工事に伴って生じる、トンネル構築領域周辺の切羽前方における地山変位を計測するための地中変位計、および地中変位計を用いた地中変位計測方法に関するものである。本実施の形態では、地中変位計をトンネル構築予定領域の側方に位置する周辺地山に設置する場合を事例に挙げ、地中変位計測方法を説明しつつ、地中変位計の詳細および地山変位の算定方法を、図1〜図10を用いて説明する。   The present invention relates to an underground displacement meter for measuring a ground displacement in front of a face around a tunnel construction area, which occurs with a tunnel excavation work, and an underground displacement measuring method using the underground displacement meter. is there. In the present embodiment, the case where the underground displacement meter is installed in the surrounding ground located on the side of the tunnel construction planned area will be taken as an example, and the details of the underground displacement meter and The method of calculating the ground displacement will be described with reference to FIGS.

≪地中変位測定方法:地中変位計10を地山に設置≫
トンネルの掘削工事を開始するにあたって、図1の平面図で示すように、掘削開始位置近傍の地山をトンネル構築予定領域Tの断面より広い範囲にわたって掘削し、拡幅部Wを構築する。この後、拡幅部Wから切羽前方のトンネル掘進方向に向けて、トンネル軸線Cと平行にボーリング孔Hを設け、このボーリング孔Hの内方に地中変位計10を挿入・設置する。
方法 Underground displacement measurement method: Underground displacement meter 10 is installed on the ground 山
When starting the tunnel excavation work, as shown in the plan view of FIG. 1, the ground near the excavation start position is excavated over a wider area than the cross section of the tunnel construction scheduled area T, and the widened portion W is constructed. Thereafter, a boring hole H is provided in parallel with the tunnel axis C from the widened portion W toward the tunnel excavation direction in front of the face, and the underground displacement meter 10 is inserted and installed inside the boring hole H.

本実施の形態では、切羽を前方に見てトンネル構築予定領域Tの左側に位置する周辺地山の1箇所にボーリング孔Hを構築して地中変位計10を設置している。しかし、地中変位計10は、トンネル構築予定領域Tの周辺地山いずれの位置に設けてもよく、その数量も1箇所に限定されるものではない。   In the present embodiment, the boring hole H is constructed at one place of the surrounding ground located on the left side of the tunnel construction scheduled area T when the face is viewed forward, and the underground displacement meter 10 is installed. However, the underground displacement meter 10 may be provided at any position on the ground near the planned tunnel construction region T, and the number thereof is not limited to one.

また、本実施の形態では、地中変位計10をボーリング孔Hの孔壁に直接設置しているが、ボーリング孔H内に孔壁保護用のパイプ材を設置してもよく、その場合には、パイプ材の内方に地中変位計10を設置すればよい。さらに、ボーリング孔Hは必ずしもトンネル軸線Cと平行でなくてもよく、トンネル軸線Cに対して所定の角度傾斜させて構築してもよい。   Further, in this embodiment, the underground displacement meter 10 is directly installed on the hole wall of the boring hole H. However, a pipe material for protecting the hole wall may be installed in the boring hole H. , The underground displacement meter 10 may be installed inside the pipe material. Further, the boring hole H may not necessarily be parallel to the tunnel axis C, and may be constructed to be inclined at a predetermined angle with respect to the tunnel axis C.

<地中変位計10:長尺部材1およびジョイント部材2>
ボーリング孔Hに挿入・設置される地中変位計10は、直列に配置される複数の長尺部材1と、隣り合う長尺部材1どうしを連結する複数のジョイント部材2と、ジョイント部材2に内装される2体の計測部3と備え、ジョイント部材2の配置位置がそれぞれ、地中変位計10における計測地点Pとなる。
<Underground displacement meter 10: long member 1 and joint member 2>
The underground displacement meter 10 inserted and installed in the boring hole H includes a plurality of long members 1 arranged in series, a plurality of joint members 2 connecting adjacent long members 1, and a joint member 2. It is provided with two measurement units 3 to be installed, and the arrangement position of the joint member 2 is a measurement point P in the underground displacement meter 10.

長尺部材1は、図1及び図2で示すように、例えばステンレス製の高い剛性を有する断面四角形状の長尺パイプよりなり、その部材長は、計測地点Pを配置したい間隔に応じて適宜設定される。本実施の形態では、地中変位を計測する計測地点Pを、例えば500mmおきに設定するべく、長尺部材1の部材長を500mmとしているが、部材長を1000mmとし計測地点Pの間隔を1000mmとしてもよい。   As shown in FIGS. 1 and 2, the long member 1 is made of, for example, a long pipe made of stainless steel and having a high rigidity and a rectangular cross section, and the length of the member is appropriately determined according to an interval at which the measurement point P is to be arranged. Is set. In the present embodiment, the length of the long member 1 is set to 500 mm in order to set the measurement point P for measuring the underground displacement at, for example, every 500 mm. However, the length of the long member 1 is set to 1000 mm, and the interval between the measurement points P is set to 1000 mm. It may be.

また、長尺部材1は、ボーリング孔H内に設置された際に断面視で、対向する2つの平面が鉛直方向を向き、他の2つの平面が水平方向を向くように配置される。これら長尺部材1は複数を直列に配置されて、ジョイント部材2を介して連結される。   In addition, when installed in the borehole H, the long member 1 is arranged such that two opposing planes face in the vertical direction and the other two planes face in the horizontal direction in a sectional view. A plurality of these long members 1 are arranged in series and connected via a joint member 2.

ジョイント部材2は、計測部3を収納している中空筒体21と、中空筒体21の両端部各々に連結される一対の継手スリーブ(鉛直回動スリーブ22及び水平回動スリーブ23)と、一対の継手スリーブ各々に接続される一対の連結金具27とを有する。   The joint member 2 includes a hollow cylindrical body 21 housing the measuring unit 3, a pair of joint sleeves (a vertical rotating sleeve 22 and a horizontal rotating sleeve 23) connected to both ends of the hollow cylindrical body 21, And a pair of connecting fittings 27 connected to each of the pair of joint sleeves.

図2で示すように、中空筒体21は、長尺部材1より内径の大きい例えばステンレス製の高い剛性を有する中空角筒体よりなり、両端部のうち一方には鉛直回動スリーブ22の一端が、他方には水平回動スリーブ23の一端がそれぞれ挿入される。鉛直回動スリーブ22及び水平回動スリーブ23は、ともに長尺部材1と同じ断面径を有する例えばステンレス製の高い剛性を有する角柱により構成される。   As shown in FIG. 2, the hollow cylindrical body 21 is formed of a hollow rectangular cylindrical body having a larger inner diameter than the long member 1, for example, made of stainless steel and having high rigidity. However, one end of the horizontal rotation sleeve 23 is inserted into the other. Each of the vertical rotation sleeve 22 and the horizontal rotation sleeve 23 is formed of, for example, a highly rigid prism made of stainless steel having the same cross-sectional diameter as the long member 1.

これら中空筒体21と鉛直回動スリーブ22及び水平回動スリーブ23は、いずれも長尺部材1と同様にボーリング孔H内に設置された際に断面視で、対向する2つの平面が鉛直方向を向き、他の2つの平面が水平方向を向くように配置される。   When the hollow cylindrical body 21, the vertical rotation sleeve 22, and the horizontal rotation sleeve 23 are all installed in the boring hole H similarly to the long member 1, the two opposing planes are in the vertical direction when viewed in cross section. And the other two planes are oriented in the horizontal direction.

そして、図2及び図3で示すように、鉛直回動スリーブ22の一端と中空筒体21の一方の端部は、軸線が水平方向に延びる水平軸ピン25が貫通され、水平回動スリーブ23の一端と中空筒体21の他方の端部は、軸線が鉛直方向に延びる鉛直軸ピン26が貫通されることにより連結される。これにより、ジョイント部材2は、中空筒体21に対して鉛直回動スリーブ22が、水平軸ピン25を軸にして鉛直方向に揺動し、水平回動スリーブ23が、鉛直軸ピン26を軸にして水平方向に揺動する、いわゆるユニバーサルジョイントとして機能する。なお、図3は、中空筒体21の内部を図示するため、中空筒体21を取り外した状態となっている。   As shown in FIGS. 2 and 3, one end of the vertical rotation sleeve 22 and one end of the hollow cylindrical body 21 are penetrated by a horizontal shaft pin 25 whose axis extends in the horizontal direction. Is connected to the other end of the hollow cylindrical body 21 by penetrating a vertical shaft pin 26 whose axis extends in the vertical direction. Accordingly, the joint member 2 is configured such that the vertical rotation sleeve 22 swings in the vertical direction about the horizontal shaft pin 25 with respect to the hollow cylindrical body 21, and the horizontal rotation sleeve 23 rotates about the vertical shaft pin 26. It functions as a so-called universal joint that swings horizontally. Note that FIG. 3 shows a state in which the hollow cylindrical body 21 has been removed in order to illustrate the inside of the hollow cylindrical body 21.

このため、中空筒体21の内径は、鉛直回動スリーブ22及び水平回動スリーブ23を挿入可能なだけでなく、鉛直回動スリーブ22の鉛直揺動及び水平回動スリーブ23の水平揺動を許容する大きさが確保されている。一方、中空筒体21の外径は、最小規格値(一般には径66mm)のボーリング孔Hに挿入・設置が可能な程度に成形するとよい。   For this reason, the inner diameter of the hollow cylindrical body 21 not only allows the vertical rotation sleeve 22 and the horizontal rotation sleeve 23 to be inserted, but also controls the vertical swing of the vertical rotation sleeve 22 and the horizontal swing of the horizontal rotation sleeve 23. Acceptable size is secured. On the other hand, it is preferable that the outer diameter of the hollow cylindrical body 21 is formed to such an extent that the hollow cylindrical body 21 can be inserted and installed in a boring hole H having a minimum specification value (generally, a diameter of 66 mm).

また、図2で示すように、中空筒体21に一端が連結されている鉛直回動スリーブ22及び水平回動スリーブ23各々の他端には、それぞれ連結金具27が接続されており、この連結金具27を介して長尺部材1が連結される。   As shown in FIG. 2, a connecting fitting 27 is connected to the other end of each of the vertical turning sleeve 22 and the horizontal turning sleeve 23, one end of which is connected to the hollow cylindrical body 21. The long member 1 is connected via the metal fitting 27.

連結金具27は、帯状鋼板を折り曲げ加工した長尺の金具本体271を備え、金具本体271の長手方向両端部各々に一対の接続板272が設けられている。一方の接続板272は鉛直回動スリーブ22もしくは水平回動スリーブ23の他端に、ボルト等の締結具24を介して締結され、他方の接続板272は、長尺部材1にボルト等の締結具24を介して締結される。   The connection fitting 27 includes a long fitting body 271 formed by bending a strip-shaped steel plate, and a pair of connection plates 272 is provided at each of both longitudinal ends of the fitting body 271. One connection plate 272 is fastened to the other end of the vertical rotation sleeve 22 or the horizontal rotation sleeve 23 via a fastener 24 such as a bolt, and the other connection plate 272 is fastened to the long member 1 with a bolt or the like. It is fastened via the tool 24.

また、金具本体271には、連結金具27を地中変位計10のセントラライザーとして機能させるべく、バネ等の弾性部材を装備した長手方向に伸縮する1本の弾性棒材273aと、ネジ等の長さ調整機能を備えた2本の長さ調整棒材273bとよりなる3本の支持棒材273が放射状に設けられている。これらはいずれも金具本体271に対して、その軸心から放射方向に延在するように設置されるとともに、先端にはボールキャスターが設置されている。なお、長さ調整棒材273bの数量は、2本に限定するものではなく、3本以上設けてもよい。   The metal fitting body 271 has a single elastic bar 273a provided with an elastic member such as a spring and extended and contracted in the longitudinal direction, and a screw or the like, so that the connecting metal fitting 27 functions as a centralizer of the underground displacement meter 10. Three support bars 273 are radially provided, each including two length-adjusting bars 273b having a length adjusting function. Each of these is installed on the metal fitting body 271 so as to extend in the radial direction from the axis thereof, and a ball caster is installed at the tip. Note that the number of the length adjusting rod members 273b is not limited to two, but may be three or more.

これらジョイント部材2を構成する、中空筒体21、鉛直回動スリーブ22、水平回動スリーブ23、連結金具27は、各々の軸心が同一線上に位置するよう配置された状態でそれぞれ連結される。そして、これらジョイント部材2に接続される長尺部材1も、その軸心がジョイント部材2の軸心と同一線上に位置するよう接続される。   The hollow cylindrical body 21, the vertical rotation sleeve 22, the horizontal rotation sleeve 23, and the connection fitting 27, which constitute these joint members 2, are connected to each other in a state where their respective axes are located on the same line. . The long members 1 connected to the joint members 2 are also connected so that their axes are located on the same line as the axis of the joint members 2.

上述する構成の地中変位計10は、地中変位計10の軸心がボーリング孔Hの軸心と合致し、また、連結金具27に備えた3本の支持部材273が孔壁に当接するように、支持部材273のうち2本の長さ調整棒材273bの長さを調整した後、孔壁にボールキャスターを当接させながら挿入・設置される。このとき、弾性棒材273aを収縮させた状態で鉛直上向きに配置するとともに、2本の長さ調整棒材273bで地中変位計10を支持するように設置する。   In the underground displacement meter 10 having the above-described configuration, the axis of the underground displacement meter 10 coincides with the axis of the boring hole H, and the three support members 273 provided on the connection fitting 27 abut against the hole wall. After adjusting the lengths of the two length adjusting rods 273b of the support member 273, the ball casters are inserted and placed in contact with the hole walls. At this time, the elastic bar member 273a is arranged vertically upward in a contracted state, and is installed so as to support the underground displacement meter 10 with two length adjusting bar members 273b.

すると、ボーリング孔H内において、弾性棒材273aは常時、鉛直上方の孔壁を押圧するとともに、その反力で2本の長さ調整棒材273bも孔壁を押圧する態様となり、地中変位計10が孔壁に対して固定される。したがって、周辺地山に変形が生じた際にも地中変位計10はボーリング孔H内で位置ズレ等を生じることがなく、周辺地山の挙動に追従して隣り合う長尺部材1間の角度をジョイント部材2を介して変化させることが可能となる。   Then, in the boring hole H, the elastic rod 273a always presses the hole wall vertically above, and the two length adjusting rods 273b also press the hole wall by the reaction force, so that the underground displacement occurs. A total of 10 is fixed to the hole wall. Therefore, even when a deformation occurs in the surrounding ground, the underground displacement meter 10 does not cause a positional shift or the like in the borehole H, and follows the behavior of the surrounding ground to allow the adjacent long members 1 to move. The angle can be changed via the joint member 2.

≪地中変位測定方法:地山変位の測定≫
上記のとおり、ボーリング孔Hに地中変位計10を挿入・設置した後、トンネル構築予定領域Tの掘削を開始する前と、掘削開始後であって切羽位置が所定距離だけ進むごとに、計測地点P各々について、ジョイント部材2に収納されている計測部3による計測を行うとともに、計測地点P各々の位置座標と、水平方向および鉛直方向の変位を算出する。
方法 Underground displacement measurement method: Measurement of ground displacement 変 位
As described above, after inserting and installing the underground displacement meter 10 in the borehole H, before starting the excavation of the tunnel construction scheduled area T, and after starting the excavation, the measurement is performed every time the face position advances by a predetermined distance. For each point P, measurement is performed by the measurement unit 3 housed in the joint member 2, and the position coordinates of each measurement point P and the displacement in the horizontal and vertical directions are calculated.

<地中変位計10:計測部3>
計測部3は、トンネル構築予定領域Tを掘削することにより生じる周辺地山の変形に伴って地中変位計10に外力が作用し、ジョイント部材2を介して連結される長尺部材1どうしが角度を持って隣り合う状態となった際に、その角度(水平方向の角度及び鉛直方向の角度)を計測するものである。本実施の形態では、図2で示すように、2体の計測部3をジョイント部材2を構成する中空筒体21の内方に配置し、中空筒体21でこれら2体の計測部3を保護している。
<Underground displacement meter 10: Measurement unit 3>
The measuring unit 3 applies an external force to the underground displacement meter 10 with the deformation of the surrounding ground caused by excavating the tunnel construction scheduled area T, and the long members 1 connected via the joint member 2 are connected to each other. When they are adjacent to each other with an angle, the angles (horizontal angle and vertical angle) are measured. In the present embodiment, as shown in FIG. 2, two measuring units 3 are arranged inside hollow cylindrical body 21 constituting joint member 2, and these two measuring units 3 are connected by hollow cylindrical body 21. Protected.

2体の計測部3はいずれも、図3で示すように、起歪板31と、固定具32と、押圧具33とを備え、板バネにより構成される起歪板31の、板面の表裏各々にひずみセンサ34が設置されている。これら2体の計測部3は、起歪板31の板面を互いに直交させた状態で並列に配置され、中空筒体21の内方で鉛直回動スリーブ22と水平回動スリーブ23とに跨るように設置されるが、設置される向きにより水平方向の角度を計測するための水平計測部3a、もしくは鉛直方向の角度を計測するための鉛直計測部3bとして取り扱われる。   As shown in FIG. 3, each of the two measurement units 3 includes a strain generating plate 31, a fixing tool 32, and a pressing tool 33, and has a plate surface of the strain generating plate 31 configured by a leaf spring. A strain sensor 34 is provided on each of the front and back sides. These two measurement units 3 are arranged in parallel with the plate surfaces of the strain plates 31 orthogonal to each other, and straddle the vertical rotation sleeve 22 and the horizontal rotation sleeve 23 inside the hollow cylindrical body 21. It is treated as a horizontal measuring unit 3a for measuring the angle in the horizontal direction depending on the installation direction, or as a vertical measuring unit 3b for measuring the angle in the vertical direction.

水平方向の角度を計測する水平計測部3aは、起歪板31の板面を水平方向に向けた状態で、起歪板31の一端が、水平回動スリーブ23の一端に固定具32により固定され、起歪板31の他端が、鉛直回動スリーブ22の一端に押圧具33を介して板面と平行な方向に摺動自在となる状態で押圧される。   The horizontal measuring unit 3a that measures the angle in the horizontal direction fixes one end of the strain plate 31 to one end of the horizontal rotation sleeve 23 with the fixture 32 with the plate surface of the strain plate 31 facing the horizontal direction. Then, the other end of the strain plate 31 is pressed to one end of the vertical rotation sleeve 22 via the pressing member 33 in a state in which it can slide in a direction parallel to the plate surface.

押圧具33は、いずれの構造のものを採用してもよいが、本実施の形態では押圧板331と押圧板331を鉛直回動スリーブ22に固定するボルト等の固定具332とにより構成し、押圧板331と鉛直回動スリーブ22の表面との間で起歪板31の他端を摺動可能な程度の押圧力で挟み込む態様としている。   The pressing member 33 may have any structure, but in this embodiment, the pressing member 33 includes a pressing plate 331 and a fixing member 332 such as a bolt for fixing the pressing plate 331 to the vertically rotating sleeve 22. The other end of the strain generating plate 31 is sandwiched between the pressing plate 331 and the surface of the vertically rotating sleeve 22 with a pressing force that is slidable.

一方、鉛直方向の角度を計測する鉛直計測部3bは、起歪板31の板面を鉛直方向に向けた状態で、起歪板31の一端が、鉛直回動スリーブ22の一端に固定具32により固定され、起歪板31の他端が、水平回動スリーブ23の一端に押圧具33を介して板面と平行な方向に摺動自在となる状態で押圧される。   On the other hand, the vertical measuring unit 3b for measuring the angle in the vertical direction includes a fixture 32 in which one end of the strain plate 31 is attached to one end of the vertical rotation sleeve 22 in a state where the plate surface of the strain plate 31 faces the vertical direction. , And the other end of the strain plate 31 is pressed against one end of the horizontal rotation sleeve 23 via the pressing member 33 in a state of being slidable in a direction parallel to the plate surface.

したがって、例えば、ジョイント部材2近傍に水平方向の外力が作用すると、図4で示すように、長尺部材1に接続された水平回動スリーブ23が中空筒体21に対して水平方向に回動する。すると、水平計測部3aの起歪板31は鉛直回動スリーブ22上を摺動しつつ、板面が撓んで水平方向に凸面を形成する。これを板面に設置されたひずみセンサ34が検知して電気信号を出力し、この出力値から、ジョイント部材2を介して隣り合う長尺部材1間の水平方向の角度αhを得ることができる。   Therefore, for example, when a horizontal external force acts on the vicinity of the joint member 2, the horizontal rotation sleeve 23 connected to the long member 1 rotates horizontally with respect to the hollow cylinder 21 as shown in FIG. I do. Then, the strain plate 31 of the horizontal measurement unit 3a slides on the vertically rotating sleeve 22 and the plate surface bends to form a convex surface in the horizontal direction. This is detected by the strain sensor 34 installed on the plate surface, and an electric signal is output. From this output value, the horizontal angle αh between the adjacent long members 1 via the joint member 2 can be obtained. .

このとき、鉛直計測部3bを構成する起歪板31は、水平回動スリーブ23上を板面と平行な方向に摺動するため変形することはなく、また、水平力が作用したことによる水平回動スリーブ23の揺動を阻害することもない。   At this time, the strain plate 31 constituting the vertical measuring unit 3b does not deform because it slides on the horizontal rotation sleeve 23 in a direction parallel to the plate surface, and does not deform due to the application of the horizontal force. There is no hindrance to the swing of the rotating sleeve 23.

同様に、ジョイント部材2近傍に鉛直方向の外力が作用した際には、鉛直回動スリーブ22が中空筒体21に対して鉛直方向に回転する。すると、鉛直計測部3bを構成する起歪板31は水平回動スリーブ23上を摺動しつつ、板面が撓んで鉛直方向に凸面を形成する。これを板面に設置されたひずみセンサ34が検知して、隣り合う長尺部材1間の鉛直方向の角度αvを得ることができる。   Similarly, when a vertical external force acts on the vicinity of the joint member 2, the vertical rotation sleeve 22 rotates in the vertical direction with respect to the hollow cylindrical body 21. Then, the strain plate 31 constituting the vertical measuring unit 3b slides on the horizontal rotation sleeve 23, and the plate surface is bent to form a convex surface in the vertical direction. This is detected by the strain sensor 34 installed on the plate surface, and the vertical angle αv between the adjacent elongated members 1 can be obtained.

このように、起歪板31は一対の継手スリーブ22、23が何れに回動しても、ひずみセンサ34が設置される板面と直交する方向にのみ変形し、水平計測部3aと鉛直計測部3b各々で計測したい方向の角度を精度よく計測することが可能となる。   In this manner, the strain plate 31 is deformed only in the direction orthogonal to the plate surface on which the strain sensor 34 is installed, regardless of which of the pair of joint sleeves 22 and 23 rotates, and the vertical measurement section 3a and the vertical measurement section 3a. It is possible to accurately measure the angle in the direction to be measured in each of the sections 3b.

上記のとおり地中変位計10は、並列に配置した水平計測部3aと鉛直計測部3bの2体の計測部3をジョイント部材2に収納しているため、ジョイント部材2の配置位置である計測地点Pにおいて、水平計測部3aの計測値である水平方向の角度αhと鉛直計測部3bの計測値である鉛直方向の角度αvの両者を、ともに計測することが可能となる。   As described above, the underground displacement meter 10 stores the two measuring units 3, the horizontal measuring unit 3 a and the vertical measuring unit 3 b, which are arranged in parallel, in the joint member 2. At the point P, both the horizontal angle αh, which is the measurement value of the horizontal measurement unit 3a, and the vertical angle αv, which is the measurement value of the vertical measurement unit 3b, can be measured together.

そして、計測地点P各々において、水平方向の角度αhと鉛直方向の角度αvの両者を計測できることにより、水平方向及び鉛直方向の位置座標を算出することができ、これにより計測地点Pにおいて、地山の水平方向の変位uhおよび鉛直方向の変位uvの両者を算出することが可能となる。   At each of the measurement points P, both the horizontal angle αh and the vertical angle αv can be measured, so that the horizontal and vertical position coordinates can be calculated. It is possible to calculate both the displacement uh in the horizontal direction and the displacement uv in the vertical direction.

<計測地点Pの位置座標および地中変位uh、uvの算出方法>
以下に、計測地点Pにおける位置座標のおよび地中変位の算出方法を説明する。本実施の形態では、平面視の位置座標と水平方向の変位uhを算出する方法を事例に挙げ、その算定方法を2パターン(第1の算定方法及び第2の算定方法)説明する。
<Method of calculating position coordinates and underground displacements uh and uv of measurement point P>
Hereinafter, a method of calculating the position coordinates and the underground displacement at the measurement point P will be described. In the present embodiment, a method of calculating the position coordinates in a plan view and the displacement uh in the horizontal direction will be described as an example, and two calculation methods (a first calculation method and a second calculation method) will be described.

なお、計測地点Pにおける平面視の位置座標と水平方向の変位uhを算出するにあたり、図1で示すように、拡幅部Wに計測補助地点Psを設定し、計測補助地点Psに係る実測値を用いる。計測補助地点Psとは、地中変位計10の最も坑口側に位置する坑口側長尺部材1aの坑口側端部の配置位置を指し、実測値は、図6(a)(b)で示すように、坑口側長尺部材1aにおける坑口側端部の平面視の位置座標(x0,y0)と、坑口側長尺部材1aの延在方向とトンネル軸線Cにより形成される角の水平方向の傾斜角βh0である。   In calculating the position coordinates in plan view and the displacement uh in the horizontal direction at the measurement point P, as shown in FIG. 1, a measurement auxiliary point Ps is set in the widened portion W, and an actual measurement value related to the measurement auxiliary point Ps is calculated. Used. The measurement auxiliary point Ps indicates the arrangement position of the wellhead-side end member of the wellhead-side long member 1a located closest to the wellhead of the underground displacement meter 10, and the measured values are shown in FIGS. As described above, the position coordinates (x0, y0) in plan view of the wellhead-side end of the wellhead-side long member 1a, the horizontal direction of the angle formed by the extending direction of the wellhead-side long member 1a, and the tunnel axis C The inclination angle is βh0.

また、図5で示すように、X軸はトンネル軸線C方向(+方向は掘進方向)であり、Y軸はトンネル軸線Cと直交する方向(−方向はトンネル軸線Cに近づく方向)、である。なお、鉛直方向(−方向は鉛直下向き)はZ軸とする。   As shown in FIG. 5, the X axis is the direction of the tunnel axis C (the + direction is the excavation direction), and the Y axis is the direction orthogonal to the tunnel axis C (the − direction is the direction approaching the tunnel axis C). . Note that the vertical direction (the-direction is vertically downward) is the Z axis.

<第1の算定方法:地中変位計10の坑口側から先端に向かって順に算出する方法>
第1の算定方法を説明するにあたり複数の計測地点Pi(i=1〜計測地点の数量)は、図6(a)で示すように、地中変位計10の最も坑口側に位置する計測地点を計測地点P1とし、地中変位計10の先端に向けて昇順に配置されているものとする。図6(a)では、事例として、計測地点Piを4点(i=1〜4)示しており、計測地点Pi間の距離はLである。
<First calculation method: Method of calculating sequentially from the wellhead side of underground displacement meter 10 toward the tip>
In describing the first calculation method, a plurality of measurement points Pi (i = 1 to the number of measurement points) are measured at the measurement point located closest to the wellhead of the underground displacement meter 10 as shown in FIG. Is the measurement point P1, and they are arranged in ascending order toward the tip of the underground displacement meter 10. FIG. 6A shows four measurement points Pi (i = 1 to 4) as examples, and the distance between the measurement points Pi is L.

そして、第1の算定方法では、拡幅部Wに位置する計測補助地点Psの実測値を基準とし、坑口側に位置する基準地点P1から先端側に向けて順に位置座標を算定する。   Then, in the first calculation method, the position coordinates are calculated in order from the reference point P1 located on the wellhead side toward the tip side based on the actually measured value of the measurement auxiliary point Ps located in the widened portion W.

まず、地中変位計10の設置後であってトンネル構築予定領域Tの掘削を開始する前の時点で、図6(a)で示すように、計測補助地点Psの位置座標(x0,y0)と切羽位置長尺部材1aのトンネル軸線Cに対する水平方向の傾斜角βh0を実測する。併せて、各計測地点Piについて、水平計測部3aの計測値である水平方向の角度αhiを計測する。   First, at the point after the installation of the underground displacement meter 10 and before starting the excavation of the tunnel construction scheduled area T, as shown in FIG. 6A, the position coordinates (x0, y0) of the measurement auxiliary point Ps. And a horizontal inclination angle βh0 of the long face member 1a with respect to the tunnel axis C is measured. At the same time, for each measurement point Pi, a horizontal angle αhi, which is a measurement value of the horizontal measurement unit 3a, is measured.

次に、各計測地点Piについて、トンネル軸線Cに対する水平方向の傾斜角βhiを、下記(1)式と、実測した傾斜角βh0及び計測値である角度αhiにより算出する。

Figure 2020041994
Next, for each measurement point Pi, the inclination angle βhi in the horizontal direction with respect to the tunnel axis C is calculated by the following equation (1), the actually measured inclination angle βh0, and the measured value αhi.
Figure 2020041994

各計測地点Piにおける平面視の位置座標を、先に実測した計測補助地点Psの位置座標(x0,y0)と(1)式で算出したβhiとに基づいて、(2)式より算出する。

Figure 2020041994
The position coordinates in plan view at each measurement point Pi are calculated from the expression (2) based on the position coordinates (x0, y0) of the measurement auxiliary point Ps actually measured and βhi calculated by the expression (1).
Figure 2020041994

上記の(1)式及び(2)式による算定を、地中変位計10の坑口側に位置する計測地点P1から先端に向かって順に繰り返し、各々の位置座標(xi、yi)を算出する。   The calculation by the above formulas (1) and (2) is repeated in order from the measurement point P1 located on the wellhead side of the underground displacement meter 10 toward the tip, and each position coordinate (xi, yi) is calculated.

上記と同様の手順を、トンネル構築予定領域Tの掘削開始後であって切羽位置が所定距離だけ進むごとに繰り返し実施する。なお、計測補助地点Psの位置座標(x0、y0)と坑口側長尺部材1aのトンネル軸線Cに対する水平方向の傾斜角βh0は、掘削作業が進むごとに変化することから、これらを実測する作業も、掘削開始前と同様に切羽位置が所定距離だけ進むごとに実施する。   The same procedure as above is repeatedly performed after the start of excavation of the tunnel construction scheduled area T and every time the face position advances by a predetermined distance. The position coordinates (x0, y0) of the measurement auxiliary point Ps and the inclination angle βh0 of the wellhead side long member 1a in the horizontal direction with respect to the tunnel axis C change every time the excavation work proceeds. This is also performed every time the face position advances by a predetermined distance, as before the start of excavation.

図7(a)に位置座標の算出結果を示すグラフ、図7(b)に水平計測部3aによる計測値αhとトンネル軸線Cに対する水平方向の傾斜角βhの一覧表を示す。なお、計測地点Pi間の距離Lは1000mmである。図7では、上記の第1の算定方法を切羽位置A(掘削開始前)の時点、及び切羽位置B〜Dの時点(位置座標を算出した時点)の合計4回にわたって行っている。これを見ると、掘削作業が進んで切羽が切羽位置A〜切羽位置Dに進むにつれて、計測補助地点Psおよび計測地点P1〜P4が徐々にトンネル軸線に近づく方向(Y軸の−方向)に移動している様子が見て取れる。特に、切羽位置Cおよび切羽位置Dの時点では、計測地点P2の位置座標が他の計測地点よりトンネル軸線側に大きく移動しており、計測地点P2付近が軟弱な地盤である可能性を含んでいる様子も見て取れる。   FIG. 7A is a graph showing the calculation results of the position coordinates, and FIG. 7B is a list of the measured values αh by the horizontal measuring unit 3a and the inclination angle βh in the horizontal direction with respect to the tunnel axis C. The distance L between the measurement points Pi is 1000 mm. In FIG. 7, the above-described first calculation method is performed a total of four times: at the time of the face position A (before the start of excavation), and at the time of the face positions B to D (time at which the position coordinates are calculated). As can be seen, as the excavation work progresses and the face advances to the face position A to the face position D, the measurement auxiliary point Ps and the measurement points P1 to P4 gradually move in a direction (− direction of the Y axis) gradually approaching the tunnel axis. You can see how they are doing. In particular, at the time of the face position C and the face position D, the position coordinates of the measurement point P2 have moved farther to the tunnel axis side than the other measurement points, and there is a possibility that the vicinity of the measurement point P2 is soft ground. You can see how they are.

次に、計測地点Pi(i=1〜計測地点の数量)各々について、切羽位置A(掘削開始前)の時点の位置座標(初期座標)と切羽位置B〜Dの時点(掘削が所定距離だけ進んだ時点)各々における位置座標の差を算出し、切羽位置B〜Dの時点各々における水平方向の変位uhを算出する。なお、水平方向の変位uhは、図5で示すようなx−y平面内のx方向変位uxおよびy方向変位uyから成るベクトル(ux、uy)である。   Next, for each of the measurement points Pi (i = 1 to the number of measurement points), the position coordinates (initial coordinates) at the time of the face position A (before the start of excavation) and the time points of the face positions B to D (excavation is performed by a predetermined distance). The difference between the position coordinates at each point in time) is calculated, and the displacement uh in the horizontal direction at each point in time of the face positions B to D is calculated. Note that the displacement uh in the horizontal direction is a vector (ux, yy) composed of a displacement ux in the x direction and a displacement yy in the y direction in the xy plane as shown in FIG.

この場合には、先に算出した切羽位置A(掘削開始前)における計測地点Pi各々の平面視における位置座標を初期座標として、(3)式の(xi0,yi0)に代入し、各計測値Piの変位uhiを算出する。

Figure 2020041994
In this case, the position coordinates in plan view of each of the measurement points Pi at the face position A (before starting excavation) calculated earlier are substituted into (xi0, yi0) of the equation (3) as initial coordinates, and each measured value is obtained. The displacement uhi of Pi is calculated.
Figure 2020041994

なお、拡幅部Wの計測補助地点Psの変位uhについても、計測地点Piと同様に上記の(3)式により算定できる。この場合には、先に実測した切羽位置A(掘削開始前)における計測補助地点Psの位置座標を初期座標として、(3)式の(xi0,yi0)に代入し、切羽位置B〜Dの時点各々における計測補助地点Psの位置座標を(xi、yi)に代入することで変位uhを算出する。   In addition, the displacement uh of the measurement auxiliary point Ps of the widened portion W can also be calculated by the above equation (3), similarly to the measurement point Pi. In this case, the position coordinates of the measurement auxiliary point Ps at the previously measured face position A (before the start of excavation) are substituted into (xi0, yi0) of Expression (3) as initial coordinates, and the face positions B to D are determined. The displacement uh is calculated by substituting the position coordinates of the measurement auxiliary point Ps at each time point into (xi, yi).

また、鉛直方向の変位uvを算定する場合には、計測補助地点Psの位置座標(x0、y0)と切羽位置長尺部材1aのトンネル軸線Cに対する水平方向の傾斜角βh0に代えて、計測補助地点Psの位置座標(x0、z0)と切羽位置長尺部材1aのトンネル軸線Cに対する鉛直方向の傾斜角βv0を実測する。併せて、各計測地点Piについて、鉛直計測部3bを用いて鉛直方向の角度αviをそれぞれ計測する。これらを用いて、上記の手順により、計測地点Pi各々の鉛直方向の位置座標および鉛直方向の変位uvを算定すればよい。なお、鉛直方向の変位uvは、図5で示すようなx−z平面内のx方向変位uxおよびz方向変位uzから成るベクトル(ux、uz)である。   When calculating the displacement uv in the vertical direction, instead of the position coordinates (x0, y0) of the measurement auxiliary point Ps and the horizontal inclination angle βh0 of the long face member 1a with respect to the tunnel axis C, the measurement auxiliary point Ps is used. The position coordinates (x0, z0) of the point Ps and the vertical inclination angle βv0 of the long face position member 1a with respect to the tunnel axis C are actually measured. At the same time, the vertical angle αvi is measured for each measurement point Pi using the vertical measurement unit 3b. Using these, the position coordinates in the vertical direction and the displacement uv in the vertical direction of each measurement point Pi may be calculated by the above procedure. Note that the vertical displacement uv is a vector (ux, uz) composed of the x-direction displacement ux and the z-direction displacement uz in the xz plane as shown in FIG.

上記の地中変位計測方法によれば、地中に削孔したボーリング孔H内に地中変位計10を、2体の計測部3に備える起歪板31の板面がそれぞれ鉛直方向および水平方向を向くように設置するのみの簡略な設置方法で、多大な手間を要することなく、複数の計測地点Pi各々で、トンネル掘削に伴い切羽前方の地山に生じる水平方向変位uh及び鉛直方向の変位uvの両者を算定することが可能となる。なお、実際に管理する値は、算出した水平方向の変位uhおよび鉛直方向の変位uvを各方向成分に分解した値ux、uy、uzである。   According to the above-mentioned underground displacement measuring method, the underground displacement meter 10 is provided in the boring hole H drilled in the ground, and the plate surfaces of the strain plates 31 provided in the two measurement units 3 are vertically and horizontally, respectively. With a simple installation method that only installs in the direction, without much labor, at each of the plurality of measurement points Pi, the horizontal displacement uh and the vertical direction generated in the ground in front of the face with tunnel excavation at each of the tunnel excavation Both of the displacement uv can be calculated. The values actually managed are values ux, ui, and uz obtained by decomposing the calculated horizontal displacement uh and the vertical displacement uv into components in each direction.

<第2の算定方法:地中変位計10の先端から後端(切羽側)に向かって算出する方法>
第1の算定方法では、各計測地点Pi(i=1〜計測地点の数量)としたが、第2の算定方法では、各計測地点Pi(i=0〜(計測地点の数量−1))と設定している。つまり、地中変位計10の最も坑口側に位置する計測地点を計測地点P1とし、地中変位計10の先端に向けて昇順に配置され、最も先端側に位置する計測地点の1つ手前をP(n−1)とする。そして、地中変位計10の最も先端側に位置する計測地点を計測地点Pnとし、拡幅部Wに設定した計測補助地点Psを計測地点P0としている。なお、図6(b)では、事例として、計測地点を4点示している(i=0〜3、n=4)。
<Second calculation method: Calculation method from the front end of the underground displacement meter 10 toward the rear end (face side)>
In the first calculation method, each measurement point Pi (i = 1 to the number of measurement points) is used, but in the second calculation method, each measurement point Pi (i = 0 to (the number of measurement points-1)). Is set. In other words, the measurement point located closest to the wellhead side of the underground displacement meter 10 is defined as the measurement point P1, and is arranged in ascending order toward the tip of the underground displacement meter 10, and one point before the measurement point located closest to the tip end Let P (n-1). The measurement point located at the most distal end side of the underground displacement meter 10 is defined as a measurement point Pn, and the measurement auxiliary point Ps set in the widened portion W is defined as a measurement point P0. In FIG. 6B, four measurement points are shown as examples (i = 0 to 3, n = 4).

そして、第2の算定方法では、第1の算定方法と異なり、地中変位計10の先端側に位置する計測地点Pnの位置座標を基準とし、坑口側に向けて最も坑口側に位置する計測地点P1および計測補助地点Psに至るまで順に位置座標を算定する。   In the second calculation method, unlike the first calculation method, the measurement located closest to the wellhead toward the wellhead is based on the position coordinates of the measurement point Pn located on the tip side of the underground displacement meter 10. The position coordinates are calculated in order up to the point P1 and the measurement auxiliary point Ps.

まず、地中変位計10の設置後であってトンネル構築予定領域Tの掘削を開始する前の時点で、第1の算定方法により、計測地点Pi(i=0〜(n−1))、Pn各々について、トンネル軸線Cに対する水平方向の傾斜角βhi、βhn、位置座標(xi、yi)、(xn,yn)を各々算出する。なお、P0(計測補助地点Ps)の位置座標(x0,y0)および傾斜角βh0は、第1の算定方法で示したように、実測値を用いる。   First, at a point after the installation of the underground displacement meter 10 and before starting the excavation of the tunnel construction scheduled area T, the measurement point Pi (i = 0 to (n−1)) is calculated by the first calculation method. For each of Pn, the horizontal inclination angles βhi and βhn with respect to the tunnel axis C and the position coordinates (xi, yi) and (xn, yn) are calculated. As the position coordinates (x0, y0) and the inclination angle βh0 of P0 (the auxiliary measurement point Ps), the actually measured values are used as described in the first calculation method.

そして、上記の算出結果のうち、地中変位計10の最も先端側に位置する計測地点Pnの位置座標(xn,yn)およびトンネル軸線Cに対する水平方向の傾斜角βhnを、掘削作業を開始した後にも変動することのない固定値として取り扱うこととし、以降の(4)式及び(5)式に用いる。   Then, of the above calculation results, the excavation operation was started with the position coordinates (xn, yn) of the measurement point Pn located at the most distal end side of the underground displacement meter 10 and the horizontal inclination angle βhn with respect to the tunnel axis C. It will be treated as a fixed value that does not fluctuate later, and will be used in the following equations (4) and (5).

トンネル構築予定領域Tの掘削作業を開始し、切羽位置が所定の距離だけ進んだところで、各計測地点P1〜P(n−1)について、水平計測部3aの計測値である水平方向の角度αhiを計測する。   Excavation work of the tunnel construction scheduled area T is started, and when the face position advances by a predetermined distance, the horizontal angle αhi, which is the measurement value of the horizontal measurement unit 3a, at each of the measurement points P1 to P (n-1). Is measured.

次に、各計測地点Piについて、トンネル軸線Cに対する傾斜角βhiを、(4)式により算出する。このとき、水平方向の角度αhnおよびトンネル軸線Cに対する水平方向の傾斜角βhnはともに、掘削開始前の時点で第1の算定方法により算定した計測地点Pnの計測値および算定値である。

Figure 2020041994
Next, for each measurement point Pi, the inclination angle βhi with respect to the tunnel axis C is calculated by equation (4). At this time, both the horizontal angle αhn and the horizontal inclination angle βhn with respect to the tunnel axis C are the measurement value and the calculation value of the measurement point Pn calculated by the first calculation method at the time before the start of the excavation.
Figure 2020041994

この後、計測地点Piにおける平面視の位置座標を、掘削開始前の時点で第1の算定方法により算定した計測地点Pnの位置座標(xn,yn)と、(4)式で算出したβhiとに基づいて、(5)式より算出する。

Figure 2020041994
Thereafter, the position coordinates in plan view at the measurement point Pi are calculated by using the position coordinates (xn, yn) of the measurement point Pn calculated by the first calculation method at the time before the start of excavation, and βhi calculated by the equation (4). Is calculated from Equation (5) based on
Figure 2020041994

上記の(4)式及び(5)式による算定を、地中変位計10の先端側に位置する計測地点P(n−1)から最も坑口側に位置する計測地点P1及び拡幅部wに位置する計測地点P0(計測補助地点Ps)に向かって順に繰り返し、各計測地点Piの位置座標(xi、yi)をそれぞれ算出する。   The calculation based on the above equations (4) and (5) is performed at the measurement point P (n-1) located on the tip side of the underground displacement meter 10 and at the measurement point P1 located closest to the wellhead side and the widened portion w. It repeats in order toward the measurement point P0 (measurement auxiliary point Ps), and calculates the position coordinates (xi, yi) of each measurement point Pi.

上記と同様の作業を、切羽位置が所定距離だけ進むごとに繰り返す。こうすると、掘削開始後では、各計測地点Piの位置座標を、水平計測部3aの計測値である水平方向の角度αh1〜αh(n−1)を計測するのみで算定でき、第1の算定方法のように、計測補助地点Psの位置座標(x0、y0)と切羽位置長尺部材1aのトンネル軸線Cに対する水平方向の傾斜角βh0を、繰り返し実測する必要が無い。   The same operation as above is repeated each time the face position advances by a predetermined distance. Thus, after the excavation starts, the position coordinates of each measurement point Pi can be calculated only by measuring the horizontal angles αh1 to αh (n−1), which are the measurement values of the horizontal measurement unit 3a, and the first calculation is performed. As in the method, it is not necessary to repeatedly measure the position coordinates (x0, y0) of the measurement auxiliary point Ps and the horizontal inclination angle βh0 of the long face position member 1a with respect to the tunnel axis C.

図8(a)に位置座標の算出結果を示すグラフ、図8(b)に水平計測部3aによる計測値αhとトンネル軸線Cに対する水平方向の傾斜角βhの一覧表を示す。なお、計測地点Pi間の距離Lは1000mmである。図8では、切羽位置A(掘削開始前)の時点では第1の算定方法により計測地点P0〜P4各々について位置座標を算定し、切羽位置B〜Dの時点各々で、第2の算定方法により計測地点P0〜P3の位置座標を算定している。なお、切羽位置B〜Dの時点では、前述したようにP4(地中変位計10の最も先端側に位置する計測地点Pn)は、掘削作業を開始した後にも変動することのない固定値として取り扱っている。   FIG. 8A is a graph showing the calculation results of the position coordinates, and FIG. 8B is a list of the measured values αh by the horizontal measuring unit 3a and the inclination angles βh in the horizontal direction with respect to the tunnel axis C. The distance L between the measurement points Pi is 1000 mm. In FIG. 8, at the time of the face position A (before the start of excavation), the position coordinates are calculated for each of the measurement points P0 to P4 by the first calculation method, and at the time of the face positions BD, the second calculation method is used. The position coordinates of the measurement points P0 to P3 are calculated. At the time of the face positions B to D, as described above, P4 (the measurement point Pn located at the most distal end of the underground displacement meter 10) is a fixed value that does not fluctuate even after the excavation work is started. We are dealing.

図8を見ると、第1の算定方法と同様に、掘削作業が進んで切羽が切羽位置A〜切羽位置Dに進むにつれて、計測補助地点P0〜P3が徐々にトンネル軸線に近づく方向(Y軸の−方向)に移動している様子が見て取れる。また、切羽位置Dの時点で、計測地点P2の位置座標が他の計測地点よりトンネル軸線側に大きく移動している様子も見て取れる。   Referring to FIG. 8, similarly to the first calculation method, as the excavation work proceeds and the face advances to the face position A to the face position D, the direction in which the measurement auxiliary points P0 to P3 gradually approach the tunnel axis (Y axis) (− Direction) can be seen. Also, at the time of the face position D, it can be seen that the position coordinates of the measurement point P2 are largely moved to the tunnel axis side from the other measurement points.

なお、各計測地点Pi各々の水平方向の変位uhを算出する方法は、第1の算定方法で示した方法と同様に、(3)式を用いればよい。   Note that the method of calculating the horizontal displacement uh of each of the measurement points Pi may use Equation (3), similarly to the method shown in the first calculation method.

また、鉛直方向の変位uvを算定する場合には、掘削開始前の計測地点P0(計測補助地点Ps)の位置座標(x0、y0)と切羽位置長尺部材1aのトンネル軸線Cに対する水平方向の傾斜角βh0に代えて、計測地点P0(計測補助地点Ps)の位置座標(x0、z0)と切羽位置長尺部材1aのトンネル軸線Cに対する鉛直方向の傾斜角βv0を実測する。併せて、各計測地点Pi、Pnについて、鉛直計測部3bの計測値である鉛直方向の角度αvi、αvnを計測する。これらを用いて上記と同様の手順により、計測地点Pi、Pn各々の鉛直方向の位置座標および鉛直方向の変位uvを算定すればよい。   When calculating the displacement uv in the vertical direction, the position coordinates (x0, y0) of the measurement point P0 (measurement auxiliary point Ps) before the start of excavation and the horizontal position of the long face member 1a with respect to the tunnel axis C are set. Instead of the inclination angle βh0, the position coordinates (x0, z0) of the measurement point P0 (measurement auxiliary point Ps) and the vertical inclination angle βv0 of the long face position elongate member 1a with respect to the tunnel axis C are actually measured. At the same time, for each of the measurement points Pi and Pn, the angles αvi and αvn in the vertical direction, which are the measurement values of the vertical measurement unit 3b, are measured. Using these, the position coordinates in the vertical direction and the displacement uv in the vertical direction of each of the measurement points Pi and Pn may be calculated in the same procedure as described above.

上記の地中変位計測方法によれば、掘削後の各計測地点Piの地山変位を、掘削作業による影響を受ける程度が最も小さい計測地点Pnの位置座標を基準に算定することから、掘削に伴うトンネル構築予定領域Tの周辺地山の挙動をより精度よく把握することが可能となる。   According to the above-described underground displacement measurement method, the ground displacement at each measurement point Pi after excavation is calculated based on the position coordinates of the measurement point Pn that is least affected by the excavation work. Accordingly, the behavior of the ground around the planned tunnel construction region T can be grasped more accurately.

また、第1の算定方法と第2の算定方法を併せて実施し算定結果の比較検証を行うと、水平方向の変位uhおよび鉛直方向の変位uvの信頼性をより高めることができる。   Further, when the first calculation method and the second calculation method are performed together and the calculation results are compared and verified, the reliability of the horizontal displacement uh and the vertical displacement uv can be further improved.

本発明の地中変位計および地中変位計を用いた地中変位計測方法は、上記実施形態に限定されるものではなく、本発明の趣旨を逸脱しない範囲で種々の変更が可能である。   The underground displacement meter and the underground displacement measuring method using the underground displacement meter of the present invention are not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

例えば、本実施の形態では、ジョイント部材2に計測部3として水平計測部3aと鉛直計測部3bをそれぞれ1体ずつ採用したが、必ずしもこれに限定するものではなく、図9で示すように、両者を2体ずつ設置してもよい。この場合には、水平計測部3aと鉛直計測部3bの各々で固定具32と押圧具33の位置が逆転するように配置するとよい。   For example, in the present embodiment, one horizontal measuring unit 3a and one vertical measuring unit 3b are adopted as the measuring unit 3 in the joint member 2, but the present invention is not necessarily limited to this, and as shown in FIG. Two of them may be installed. In this case, the horizontal fixture 3a and the vertical fixture 3b should be arranged such that the positions of the fixing tool 32 and the pressing tool 33 are reversed.

また、例えば、水平計測部3aを2体、鉛直計測部3bを1体という具合に、地盤特性や変位を把握した方向の重要度等により、変則的な数量で設置してもよく、さらには、鉛直回動スリーブ22及び水平回動スリーブ23の内面及び外面の両者を利用して、最大8体の計測部3を設けることも可能である。   In addition, for example, two horizontal measuring units 3a and one vertical measuring unit 3b may be installed in irregular amounts depending on the importance of the direction in which the ground characteristics and displacement are grasped, and so on. It is also possible to provide a maximum of eight measuring units 3 using both the inner surface and the outer surface of the vertical rotation sleeve 22 and the horizontal rotation sleeve 23.

さらに、計測部3は、必ずしも図3で示すような構造に限定されるものではなく、例えば、図10で示すように、鉛直回動スリーブ22及び水平回動スリーブ23各々に対して、起歪板31と、これに直交して設置される押圧板331の両者を一体に備える構成としてもよい。こうすると、起歪板31を鉛直回動スリーブ22もしくは水平回動スリーブ23に固定する固定具32、および押圧板331を鉛直回動スリーブ22もしくは水平回動スリーブ23に固定する固定具332、の両者が不要となり、また、押圧板331も別途製作する必要がないため、部材点数を減少させてより簡略な構成とすることが可能となる。   Further, the measuring unit 3 is not necessarily limited to the structure as shown in FIG. 3. For example, as shown in FIG. The plate 31 and the pressing plate 331 installed orthogonal to the plate 31 may be integrally provided. Thus, the fixing tool 32 for fixing the strain plate 31 to the vertical rotation sleeve 22 or the horizontal rotation sleeve 23 and the fixing tool 332 for fixing the pressing plate 331 to the vertical rotation sleeve 22 or the horizontal rotation sleeve 23 are provided. Since both are unnecessary and the pressing plate 331 does not need to be separately manufactured, the number of members can be reduced and a simpler configuration can be achieved.

また、地中変位計10は、端末装置(図示せず)無線接続させておくとよい。端末装置は、演算処理装置、入力部、出力部及び記憶部等を備えた、いわゆるノート型パソコンやタブレット端末である。そして、地中変位計10に備えた計測部3の電気信号を入力部より端末装置に入力させるととともに、演算処理装置に上記第1の算定手段により計測地点Pの位置座標および水平方向の変位uh及び鉛直方向の変位uvを算定する第1の算定部を格納しておく。   The underground displacement meter 10 may be wirelessly connected to a terminal device (not shown). The terminal device is a so-called notebook computer or tablet terminal including an arithmetic processing device, an input unit, an output unit, a storage unit, and the like. Then, the electric signal of the measuring unit 3 provided in the underground displacement meter 10 is input from the input unit to the terminal device, and the arithmetic processing unit uses the first calculating unit to calculate the position coordinates and the horizontal displacement of the measuring point P. uh and a first calculating unit for calculating the vertical displacement uv are stored.

同様に、演算処理装置に上記第2の算定手段により計測地点Pの位置座標および水平方向の変位uh及び鉛直方向の変位uvを算定する第2の算定部を格納しておく。こうすると、管理者は現場や管理事務所等において、端末装置に備えたディスプレィ等の出力装置に、図7及び図8で示すような計測地点Pの算出結果を表示させ、トンネル構築予定領域Tの周辺地山の変形挙動をモニタリングすることが可能となる。   Similarly, a second calculation unit for calculating the position coordinates of the measurement point P, the horizontal displacement uh, and the vertical displacement uv by the second calculation means is stored in the arithmetic processing device. In this way, the administrator displays the calculation result of the measurement point P as shown in FIGS. 7 and 8 on an output device such as a display provided in the terminal device at the site or the management office, and displays the tunnel construction scheduled area T It is possible to monitor the deformation behavior of the surrounding mountain in the area.

1 長尺部材
2 ジョイント部材
21 中空筒体
22 鉛直回動スリーブ(一対の継手スリーブ)
23 水平回動スリーブ(一対の継手スリーブ)
24 締結具
25 水平軸ピン
26 鉛直軸ピン
27 連結金具
271 金具本体
272 接続板
273 支持棒材
273a 弾性棒材
273b 長さ調整棒材
3 計測部
3a 水平計測部
3b 鉛直計測部
31 起歪板
32 固定具
33 押圧具
331 押圧板
332 固定具
34 ひずみセンサ
10 地中変位計
H ボーリング孔
P 計測地点
T トンネル構築予定領域
W 拡幅部
DESCRIPTION OF SYMBOLS 1 Long member 2 Joint member 21 Hollow cylinder 22 Vertical rotation sleeve (a pair of joint sleeves)
23 Horizontal rotating sleeve (a pair of joint sleeves)
Reference numeral 24 Fastener 25 Horizontal axis pin 26 Vertical axis pin 27 Connection fitting 271 Metal fitting body 272 Connection plate 273 Supporting rod 273a Elastic rod 273b Length adjusting rod 3 Measuring unit 3a Horizontal measuring unit 3b Vertical measuring unit 31 Strain plate 32 Fixing device 33 Pressing device 331 Pressing plate 332 Fixing device 34 Strain sensor 10 Underground displacement meter H Boring hole P Measurement point T Tunnel construction planned area W Widening section

Claims (5)

地中に削孔された孔内に設置されて地中変位を計測する地中変位計であって、
直列に配置される複数の長尺部材と、
隣り合う該長尺部材どうしを連結する複数のジョイント部材と、
該ジョイント部材に収納され、板面にひずみセンサが設置される起歪板を備える2体の計測部と、を備え、
前記ジョイント部材が、
直列に配置され、前記長尺部材の端部に接続される一対の継手スリーブと、
一対の該継手スリーブ間に配置され、該継手スリーブが互いに直交する方向に回動自在となるように接続される中空筒体とを有し、
該中空筒体の内側に2体の前記計測部が、前記起歪板の板面を互い直交する方向に向けて、一対の前記継手スリーブに跨って並列に設置されることを特徴とする地中変位計。
An underground displacement meter installed in a hole drilled in the ground to measure underground displacement,
A plurality of long members arranged in series,
A plurality of joint members for connecting the adjacent long members,
Two measurement units housed in the joint member and provided with a strain-generating plate on which a strain sensor is installed on the plate surface,
The joint member,
A pair of joint sleeves arranged in series and connected to the end of the long member,
A hollow cylindrical body disposed between the pair of the joint sleeves and connected so that the joint sleeves are rotatable in directions orthogonal to each other;
A ground, wherein two measurement units are installed in parallel across a pair of the joint sleeves, with the plate surfaces of the strain generating plate facing in directions perpendicular to each other, inside the hollow cylindrical body. Medium displacement meter.
請求項1に記載の地中変位計において、
前記計測部が、前記起歪板の一端を一方の前記継手スリーブに固定する固定具と、他端を他方の前記継手スリーブに対して前記板面と平行な方向に摺動自在に押圧する押圧具と、を備えることを特徴とする地中変位計。
The underground displacement meter according to claim 1,
A fixture for fixing one end of the strain plate to one of the joint sleeves, and a presser for slidably pressing the other end against the other joint sleeve in a direction parallel to the plate surface; And an underground displacement meter.
請求項1または2に記載の地中変位計において、
前記ジョイント部材に、前記継手スリーブと前記長尺部材との間に配置されて両者を接続する金具本体と、該金具本体の外面に先端を前記孔の孔壁に向けて放射状に設置される複数の支持棒材と、を有する連結金具を一対備え、
前記支持棒材は、長手方向に伸縮する弾性棒材を1本含む少なくとも3本以上設置されることを特徴とする地中変位計。
The underground displacement meter according to claim 1 or 2,
A metal fitting body disposed between the joint sleeve and the long member to connect the joint member to the joint member; and a plurality of metal fittings radially installed on the outer surface of the metal fitting body with their tips directed toward the hole wall of the hole. And a pair of connecting brackets having
The underground displacement meter is characterized in that at least three or more support bars including one elastic bar that expands and contracts in the longitudinal direction are installed.
トンネル構築予定領域の周辺地山に請求項1から3のいずれか1項に記載の地中変位計を、切羽近傍からトンネル掘進方向に延在する削孔に挿入するとともに、2体の前記計測部各々の前記起歪板が板面をそれぞれ鉛直方向および水平方向に向くようにして設置した後、
最も坑口側に位置する前記長尺部材の坑口側端部を計測補助地点、2体の前記計測部が収納される複数の前記ジョイント部材の配置位置を計測地点として設定し、
前記掘削開始前、および掘削を開始し切羽位置が所定の距離だけ進むごとに、複数の前記計測地点各々で計測を行い、
掘削開始前および掘削開始後に計測を行った各時点における前記計測地点各々の位置座標を、前記計測補助地点の位置座標を基準とし、複数の前記計測地点で得た計測値のうちの自己よりも坑口側に位置する前記計測地点の計測値に基づいて算定し、
複数の前記計測地点各々における掘削前後の位置座標の変位を、鉛直方向および水平方向各々で算定することを特徴とする地中変位算定方法。
The underground displacement meter according to any one of claims 1 to 3 is inserted into a borehole extending in the tunnel excavation direction from a vicinity of a face in a ground around the planned tunnel construction area, and the two measurements are performed. After setting the strain plate of each part so that the plate surface faces the vertical direction and the horizontal direction respectively,
The pit side end of the long member located closest to the pit side is set as a measurement auxiliary point, and the arrangement position of the plurality of joint members in which the two measurement units are stored is set as a measurement point.
Before the start of the excavation, and every time the excavation is started and the face position advances by a predetermined distance, measurement is performed at each of the plurality of measurement points,
The position coordinates of each of the measurement points before and after the start of excavation and at the time of measurement after the start of excavation, based on the position coordinates of the measurement auxiliary point, Calculated based on the measured value of the measurement point located on the wellhead side,
An underground displacement calculation method, wherein displacements of position coordinates before and after excavation at each of the plurality of measurement points are calculated in each of a vertical direction and a horizontal direction.
トンネル構築予定領域の周辺地山に請求項1から3のいずれか1項に記載の地中変位計を、切羽近傍からトンネル掘進方向に延在する削孔に挿入するとともに、2体の前記計測部各々の前記起歪板が板面をそれぞれ鉛直方向および水平方向に向くようにして設置した後、
最も坑口側に位置する前記長尺部材の坑口側端部を計測補助地点、2体の前記計測部が収納される複数の前記ジョイント部材の配置位置を計測地点として設定し、
前記掘削開始前および掘削を開始し切羽位置が所定の距離だけ進むごとに複数の前記計測地点各々で計測を行い、
掘削開始前における前記計測地点各々の位置座標を、前記計測補助地点の位置座標を基準とし、複数の前記計測地点で得た計測値のうちの自己よりも坑口側に位置する前記計測地点の計測値に基づいて算定し、
掘削開始後に計測を行った各時点における前記計測地点各々の位置座標を、掘削前に算定した前記地中変位計の最も先端側に位置する計測地点の位置座標を基準とし、複数の前記計測地点で得た計測値のうちの自己よりも先端側に位置する前記計測地点の計測値に基づいて算定し、
複数の前記計測地点各々における掘削前後の位置座標の変位を、鉛直方向および水平方向各々で算定することを特徴とする地中変位算定方法。
The underground displacement meter according to any one of claims 1 to 3 is inserted into a drilling extending from a vicinity of a face to a tunnel excavation direction in a ground around a tunnel construction scheduled area, and the two measurements are performed. After setting the strain plate of each part so that the plate surface faces the vertical direction and the horizontal direction respectively,
The pit-side end of the long member located closest to the pit side is set as a measurement auxiliary point, and the arrangement position of the plurality of joint members in which the two measurement units are stored is set as a measurement point.
Before the start of excavation and start excavation, every time the face position advances by a predetermined distance, measure at each of the plurality of measurement points,
The position coordinates of each of the measurement points before the start of excavation, with reference to the position coordinates of the measurement auxiliary point, of the measurement values obtained at the plurality of measurement points, measurement of the measurement point located on the wellhead side with respect to itself. Calculated based on the value,
The position coordinates of each of the measurement points at each time point when the measurement was performed after the start of the excavation, based on the position coordinates of the measurement point located at the most distal end side of the underground displacement meter calculated before the excavation, a plurality of the measurement points Calculated based on the measurement value of the measurement point located on the tip side than the self of the measurement values obtained in,
An underground displacement calculation method, wherein displacements of position coordinates before and after excavation at each of the plurality of measurement points are calculated in each of a vertical direction and a horizontal direction.
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