JPH0344165B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field The present invention relates to an in-ground system that detects displacement of a measurement target point with respect to a measurement reference point in the ground by converting it into an electrical quantity using a displacement converter (so-called displacement meter). The present invention relates to a displacement detection device.

(b) Prior art There is a subsidence measurement device as a displacement detection device in the ground. This subsidence measuring device is essential equipment for investigating ground subsidence caused by urban civil engineering such as underground water pumping and underground construction, or for investigating dynamic changes in submarine ground prior to marine civil engineering. It is also important when measuring the amount of vertical subsidence of earth and sand in embankments such as field dams.

Among these subsidence measuring devices, the latter used for dams is generally called a stratified subsidence measuring device or a stratified subsidence meter, and measures the subsidence of each layer of the dam. It is widely used to measure the amount of subsidence in each stratum during and after the construction.

Conventionally, this type of stratified settlement measuring device, as shown in Fig. 1, has a main pipe (made of vinyl chloride) that also serves as a guide, attached to the anchor part _a1 of the dug foundation (fixed layer) a. A support pipe (b) is installed via a joint (c), and a plurality of cross arms (d) made of metal material are installed horizontally at regular intervals on this main pipe (b) so as to be able to slide. Each settling plate (also called a settling plate) is attached to the free end of d.
On the other hand, a panel board g is installed on the upper part _b1 of the main pipe b protruding above the ground f which has been embanked, and the above ground f
A magnetic induction type searcher j using an electromagnet is attached to one end of a cable (suspension rope) i wound around the hoisting drum of a hoisting machine vh installed in The child j is provided so that it can be moved up and down in the vicinity of the cross arm d attached to the main pipe b via a guide roller _g1 attached to the panel board g.

For example, in the above-described conventional layered settlement amount measurement device, when measuring the amount of settlement of sediment in a dam embankment, the cable i is inserted into the main pipe b buried in the earth and sand via a guide roller _g1. By letting out the cable i and lowering the magnetic induction probe j attached to one end of the cable i without contact,
This magnetic induction type probe j detects the amount of subsidence of the cross arm d, which is made of a metal material and is integrated with the above-mentioned settling plate e, which is subsided by the earth and sand, and displays this on the display section g ₂ of the operation panel g via the above-mentioned cable i. The sensor senses the scale at the point where the reaction occurred and measures the amount of settling.

However, with the above-mentioned conventional layered settlement measuring device, the anchor part a ₁ , cross arm d, and each settling plate e must be buried at the same time as the dam is constructed, which makes setting up the device complicated and takes a long time. There is a drawback. In addition, in the case of an artificial structure such as a dam, it is possible to install the device if the above-mentioned labor is excluded, but when measuring the amount of subsidence of existing ground or seabed ground, it is necessary to install the device. The device must be buried after digging down the ground, and it is extremely difficult from a technical and economic standpoint to drill a hole large enough to accommodate the burying work space.

On the other hand, in order to solve the above-mentioned difficulties of the conventional device, it is necessary to provide, for example, a screw action on the main body side of the displacement transducer or the other end of the displacement transmission rod whose one end is connected to the displacement sensing part of the displacement transducer. It is thought that it would be sufficient to provide a pantograph-shaped anchor that expands and contracts, and to extend above the ground an operating rod that is threadedly connected to the pantograph-shaped anchor. In such a stratified settlement measurement device, it is inserted into an observation hole drilled in the ground to be measured, and at a predetermined depth position, the operating rod is rotated to expand the pantograph-shaped anchor. By digging into the peripheral wall of the observation hole, it is possible to fix the other end of the displacement transmitting rod or the main body side of the displacement converter to the ground.

However, the stratified settlement measurement device configured in this way uses the ground (e.g. earth and sand) in the observation hole as a fixed part (reaction part) to turn the operating rod, so it is difficult to use the ground when the ground is quite hard. If you do not have
The anchor is spinning and the anchor cannot be opened. In addition, the mechanism for opening and closing the pantograph-shaped anchor is heavy and bulky, so
There is a problem in that it is not possible to derive a plurality of cables for deriving detection signals from the operating rod or the displacement transducer, and therefore it is not possible to detect displacement across multiple layers.

(c) Purpose The present invention was made in view of the above circumstances, and its purpose is to use a simple structure to accurately and accurately position multi-stage anchors at predetermined depth positions in observation holes drilled in the ground. To provide a displacement detection device in the ground that can be installed reliably and easily, and that can detect displacements such as subsidence of existing artificial structures and seabed ground over multiple layers.

(d) Configuration The present invention is an in-ground displacement detection device that detects the displacement of a measurement target point with respect to a measurement reference point in the ground by converting it into an electrical quantity using a displacement converter. A displacement transducer that outputs a detection signal corresponding to the relative displacement, a displacement transmission rod whose one end is connected to the displacement sensing section of the displacement transducer, and a displacement transmission rod provided at the other end of the displacement transmission rod. A slider crank mechanism is formed by a slider and at least one pair of links, and an anchor part in which the pair of links opens and closes in an umbrella shape by sliding the slider; and a fluid pressure jack that is fixed and slides the slider by supplying or discharging pressure fluid from the outside, and is inserted into a predetermined position in an observation hole drilled in the ground to supply fluid with increased pressure from the outside. The anchor part is configured to be opened in an umbrella shape and press-fitted into the side wall of the observation hole by supplying the fluid pressure jack to the fluid pressure jack,
With such a configuration, the above object can be completely achieved.

Hereinafter, the configuration of the present invention will be explained in detail based on an illustrated embodiment.

FIG. 2 is a side view showing the configuration of one embodiment of the anchor part, which is the main part of the present invention, and shows the anchor part installed in an observation hole drilled in the ground to be measured.

In the figure, reference numeral 1 indicates the ground to be measured, such as the seabed or a construction site, and an observation hole 2 of a predetermined depth is bored by a drilling machine or the like. 3 is
A displacement transmission rod made of stainless steel is inserted into the observation hole 2, and a hydraulic jack 4 as a fluid pressure jack is held and fixed to the distal end side of the rod by a mounting portion 5. This hydraulic jack 4 has a piston rod 6 protruding toward the tip side of the displacement transmission rod 3, and the piston rod is moved by nitrogen gas or oil supplied via a hydraulic pipe 7 from a compressor pump (not shown) installed above ground. 6 extrusions are performed. Hydraulic jack 4
The more protruding tip of the piston rod 6 is connected to a slider 8 which is slidably inserted into the displacement transmission rod 3.
(upper end surface in the figure). One end of a first link 9 is rotatably supported on the slider 8 by a pin 10, and a second link 11 is provided at an intermediate portion of the first link 9.
One end of the second link 11 is rotatably supported by a pin 12, and the other end of the second link 11 is connected to an anchor tip 1 fixed to the tip of the displacement transmission rod 3.
3 with a pin 14 so as to be rotatable. These first links 9, second links 11
are arranged at four symmetrical positions around the displacement transmission rod 3, and in addition, the four members of the slider 8 and the displacement transmission rod 3 constitute a slider crank mechanism (or slider crank chain). It also constitutes an anchor part 15 which, when opened, bites into the side wall of the observation hole 2 and serves to fix the displacement transmission rod 3. Reference numeral 16 denotes a stopper, and when the slider 8 is pushed down by a predetermined distance by the piston rod 6, one end of the stopper 16, which had been fitted into a slit (not shown) drilled in the displacement transmission rod 3, protrudes. to lock the upper end surface of the slider 8, and
prevent it from returning upward. Reference numeral 17 denotes a casing pipe for isolating the displacement transmitting rod 3, which is connected to a displacement converter to be described later, from the surrounding earth and sand.This pipe 17 allows the displacement transmitting rod 3 to come into contact with the surrounding earth and sand. Displacement is prevented from being blocked. Therefore, this casing pipe 17
A pipe made of vinyl chloride or the like having a small coefficient of friction is used, and the end thereof is sealed with a truncated cone-shaped rubber seal.

To explain the function of the anchor shown in the second figure and constructed as described above, after drilling the observation hole 2 in the ground 1 with a boring machine, etc., a compressor (not shown) is inserted into the hydraulic jack 4 (cylinder). When pressurized liquid (oil) is supplied from the pump through the hydraulic pipe 7, the piston (not shown) in the hydraulic jack 4 moves, and the piston rod 6 connected to it also gradually lowers, causing the anchor portion 15 to move. Push the slider 8 downward in the figure. Then, the first link 9 and the second link 11, which had been folded in a state substantially parallel to the displacement transmission rod 3,
As the distance between the pins 10 and 14 that pivot each end becomes shorter, the displacement transmission rod 3 gradually becomes smaller.
It opens as the angle increases, and finally, as shown in Figure 2, it rotates to about 90 degrees, and its tip bites into (press-fits) the side wall of the observation hole 2 in the ground 1. In this way, the displacement transmission rod 3
is securely fixed to the ground at a predetermined depth within the observation hole 2 by the anchor portion 15.

FIG. 3a is a longitudinal sectional view showing the configuration of an embodiment of the displacement transducer according to the present invention, and FIG. 3b, c, and d are sectional views taken along line A-A in FIG. They are a sectional view taken along the line B and a sectional view taken along the line CC.

In FIGS. 3a to 3d, the outer circumference of the main body of the displacement transducer 18 is protected by a cylindrical protection tube 19,
Lid bodies 20a and 20b are screwed onto both ends thereof, respectively. Among the lids 20a and 20b, one of the lids 20a is provided with conduction holes 21 at six locations in the case of the same embodiment, and six rods as displacement sensing portions are inserted from inside the displacement transducer 18. 22 protrudes in a freely extending (or retractable) state, and the protruding portion is fitted into a shield pipe 23 for maintaining airtightness within the displacement transducer 18. The tip of each rod 22 protruding from the displacement transducer 18 is connected to one end of the displacement transmitting rod 3 shown in FIG. 2, respectively. Of the lid body 20a,
A columnar pedestal 24 is fixed at the center of the inner surface of the displacement transducer 18 . This pedestal 24 has
One end side of six cantilevers 25 is fixed along the axial direction at angular intervals of 60 degrees from each other, and the surface of the cantilever 25 is perpendicular to the displacement direction of each rod 22 as a displacement sensing section. A coil spring 26 is suspended between one end of each rod 22 in the displacement transducer 18 and the other end of each cantilever 25.
Strain gauges 27 are attached to the surfaces of the cantilevers 25, each of which changes its resistance when subjected to strain. This strain gauge 27 is connected to each rod 2.
Convert the displacement amount of 2 into the corresponding electric amount.
Strain gauge 2 attached to each cantilever 25
The output cables 28 respectively connected to the terminals 7 and 7 are led out to the outside of the displacement converter 18 through an output cable protection tube 29 bored inside the displacement converter 18 at the center of the other lid 20b. This led out output cable 28 is connected to a joint box 3 which is adjacent to the lid body 20b and which is filled with a moisture-proofing agent.
0, a plurality of cables are grouped together and led out from a joint box 30 as a small number of output cables 31. A coupling rod 32 is attached to one end of the joint box 30 for coupling with a transducer fixing anchor (described later) that fixes the entire displacement transducer 18 within the observation hole 2.

The displacement transducer 18 configured in this manner operates as follows.

Changes in the position of each anchor part 15 (shown in the second diagram) due to ground subsidence etc. are directly transmitted to each rod 22,
The displacement of each rod 22 is damped by each coil spring 26, causing each cantilever 25 to flex.
The deflection of each cantilever 25 is that of the cantilever 2.
A change in the electrical output of the strain gauge 27 attached to the strain gauge 5 is detected by a measuring device (not shown) installed on the ground via each output cable 28, 31.

FIG. 4 shows the anchor part 15 shown in FIG.
It is a schematic side view which shows the state when the subsidence measurement apparatus which has the displacement transducer 18 shown in a figure as a main part is installed in the seabed ground.

In the figure, 33 is the seabed, 15a is a displacement fixing anchor attached to the connecting rod 32 on one end side of the displacement converter 18 shown in FIG. 3 for fixing the displacement converter 18, and 15b, 15c are: These are rod fixing anchors for fixing the displacement transmission rods 3b and 3c, respectively. These anchors 15a, 15b, 15c have the same structure as shown in FIG. 2, and in FIG. 4, illustration of each hydraulic jack 4 and the hydraulic pipe 7 connected to it and supplying oil is omitted. There is.

Next, the installation procedure of the subsidence measuring device will be described based on Fig. 4.

First, an observation hole 2 is drilled to a predetermined depth in the seabed 33 using a drilling machine, and a casing pipe is inserted into the upper part of the observation hole 2 to prevent the observation hole 2 from collapsing. Next, each anchor 15a, 15b, 15
Displacement transducer 1 so that c is located at the measurement target location.
8. Displacement transmission rod 3 and anchor 15a, 1
5b and 15c are connected to each other. The entire device connected in this way is attached to the transducer fixing anchor 15.
Insert it into the observation hole 2 using the insertion rod (not shown) connected to the a side, and insert it into each hole 15a, 15b,
Once it is confirmed that the rods 15c have reached their respective predetermined positions in the observation hole 2, the hydraulic jacks 4 attached to the rod fixing anchors 15b and 15c are
The first link 9 of the anchors 15b, 15c is attached to the hole wall of the observation hole 2 by injecting pressurized fluid (in this case, oil) into the hole (as shown in the second diagram) from an external compression pump through the hydraulic pipe 7. Extend and fix. While confirming that the anchors 15b and 15c are completely fixed to the hole wall using the indicator of the measuring device installed outside, insert the displacement transducer 1 with the insertion rod.
8 and perform zero point adjustment. Next, the displacement transducer 18 is fixed by pressurizing oil into the hydraulic jack 4 of the transducer fixing anchor 15a to cause the first link 9 to protrude and bite into the hole wall. After these operations are completed, the lock pin (not shown) of the insertion rod is removed and pulled out from the apparatus, and then the casing pipe (not shown) inserted into the observation hole 2 for protection is pulled out. After checking the equipment status and zero point again using a measuring device installed on the sea, the output cable 3
1 (the outer skin is protected by a spring hose or the like, although not shown) is laid on the seabed 33 and set up on the sea.

The subsidence measuring device installed in the ground 1 of the seabed 33 as described above records changes in the ground 1 over time using a self-recording recorder connected to a measuring device on the sea. At this time, the data obtained by the instrument is shown in FIG.
This is a change in the relative distance between the displacement converter 18 fixed by the rod fixing anchor 15b and the rod fixing anchor 15c, that is, the displacement.
Therefore, for example, when the rod fixing anchor 15c is located on a fixed layer where the ground does not move, the displacement of each measurement point on the ground 1 can be detected using the position of the rod fixing anchor 15c as a measurement reference. Also, among the anchors 15a to 15c, for example, the absolute height (altitude) of the anchor 15a near the seabed is
The elevations of the other anchors 15b and 15c can be determined by performing leveling using a known benchmark as a reference.

Next, FIG. 5 is a schematic side view showing a state in which a subsidence measuring device according to an embodiment of the present invention is installed below the ground surface.

In the figure, numeral 34 is a manhole chamber provided below the ground surface 35 such as a road, and the displacement converter 18 is fixed within this manhole chamber 34. Directly below the manhole room 34 is an underground passage 36 for a subway, etc., and the observation hole 2 is directed toward the underground passage 36.
is drilled. In this observation hole 2, rod fixing anchors 15b and 1 are installed in the same manner as in the case of FIG.
5c is fixedly installed.

When the subsidence measurement device is installed above the underground passage 36 in this way, it is possible to know the influence of ground subsidence due to the construction of the underground passage.

According to the embodiment constructed and operated as described above, the following advantages can be obtained.

That is, unlike the conventional device shown in Fig. 1, in which a displacement detection device cannot be installed unless a dam or the like is being constructed, the device of this embodiment has a drilling machine etc. installed in the ground 1. Observation hole 2 with a smaller diameter
Since the drilling cost is low, the device can be easily installed not only in artificial constructions such as dams, but also in the seabed and underground as mentioned above, which greatly expands the range of possible installations. Expanded. In particular, as mentioned above, when the operating rod is rotated to open the anchor from the ground, it is difficult to install the anchor if the ground is soft. By injecting pressurized fluid into the jack from the shore (or from the sea), the anchor can be reliably and accurately installed in a predetermined position, no matter how soft the ground is.

In addition, the above embodiment basically has a displacement transducer 1
8. Anchor part 1 consisting of a slider crank chain
5. Displacement transmission rod 3 and hydraulic jack 4-4
Since it only uses parts, its structure is simple, light in weight, and not particularly bulky.
The anchor portions 15 can be installed in multiple stages (layers), that is, displacement across multiple layers can be detected. Therefore, deformations in the ground can be grasped more accurately than before.

Note that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.

For example, each anchor portion 15 is connected to a first link 9 that shares the slider 8 and the displacement transmission rod 3.
An example of a configuration using four pairs of slider-crank chains, each pair consisting of a second link 11 and a second link 11, is shown.
There is no restriction on the number of pairs as long as the anchor portion 15 can be securely fixed to the anchor portion 15. However, anchor 1
When installing 5 in multiple stages, use the displacement transmission rod 3
Since a large amount of space is required for the hydraulic pipes 7 and 7 to pass through, it is desirable that the number of pairs be small.

Further, in the above-described embodiment, an example was shown in which the observation hole 2 was drilled in the vertical direction, but even when the observation hole 2 is bored in the horizontal or diagonal direction, the anchor portion can be easily and reliably installed.

Furthermore, an example in which the present invention is applied to a stratified subsidence measurement device is shown, but the present invention is also applicable to a multi-stage rock displacement meter that detects displacement within the underground rock where underground structures are constructed, and to various layers of embankment in earth dams and rockfield dams. It can also be applied to other applications such as vertical and horizontal displacement meters that can be installed underground to detect vertical subsidence and horizontal expansion within the embankment over a long period of time.

(e) Effects As detailed above, according to the present invention, multi-stage anchors can be installed accurately, reliably, and easily at predetermined depth positions in observation holes drilled in the ground with a simple configuration. As a result, it is possible to provide an in-ground displacement detection device that can detect displacements such as subsidence in existing artificial structures and undersea ground over multiple layers.

[Brief explanation of drawings]

FIG. 1 is a side view of a conventional stratified settlement measuring device in an installed state, FIG. 2 is a side view showing the configuration of an embodiment of the anchor part, which is the main part of the present invention, and FIG. , are vertical cross-sectional views showing the configuration of an embodiment of the displacement transducer according to the present invention, and FIGS.
are sectional views taken along line A-A in FIG. 3a, respectively;
A sectional view taken along the line B-B and a sectional view taken along the line C-C. It is a side view which shows the state in which the subsidence measuring device based on another Example was installed in the ground just above an underground passage. 1...Ground, 2...Observation hole, 3, 3a, 3b...
...Displacement transmission rod, 4...Hydraulic jack, 6...
Piston rod, 7... Hydraulic pipe, 8... Slider, 9... First link, 11... Second link, 13... Anchor tip, 15... Anchor part, 15a... Converter fixing anchor, 15b,1
5c... Rod fixing anchor, 18... Displacement converter, 19... Protection tube, 22... Rod, 24...
Pedestal, 25... Cantilever, 26... Coil spring, 27... Strain gauge, 28, 31...
...output cable, 32...coupling rod, 36...
Underpass.

Claims (1)

[Claims] 1. In a ground displacement detection device that detects the displacement of a measurement target point with respect to a measurement reference point in the ground by converting it into an electrical quantity using a displacement converter, the displacement sensing part is displaced relative to the main body side member and the displacement is detected. a displacement transducer that outputs a detection signal corresponding to the displacement transducer; a displacement transmission rod having one end connected to the displacement sensing portion of the displacement transducer; and a slider and at least one pair of links provided at the other end of the displacement transmission rod. A slider crank mechanism is formed by an anchor part in which the pair of links opens and closes in an umbrella shape by sliding the slider, and an anchor part that is fixed to the displacement transmission rod in proximity to the anchor part and receives pressurized liquid from the outside. a liquid pressure jack that causes the slider to slide by supplying the liquid to the fluid pressure jack, the liquid being inserted into a predetermined position in an observation hole drilled in the ground and having increased pressure from the outside; . A displacement detection device in the ground, characterized in that the anchor portion is configured to open in an umbrella shape and be press-fitted and fixed to a side wall of the observation hole.