JP4922200B2 - Concrete placement control method and concrete placement system - Google Patents

Description

  The present invention relates to a method and a concrete placement system for controlling placement of uncured concrete before demolding in a cast-in-place lining method.

  Conventionally, in forming a shield tunnel, a cast-in-place lining method, an extruded concrete lining method, and an ECL (Extruded Concrete Lining) method are used. A construction method is used in which a frame is assembled in an annular shape, concrete is poured between the inner mold frame and the excavated ground, and lining concrete is constructed to form a tunnel (see, for example, Patent Document 1). .

JP 2006-241800 A

  However, until now there has been no means to accurately measure the lining thickness of uncured concrete before demolding, and the concrete lining thickness is estimated indirectly from the placement pressure and placement amount and cured. The concrete was managed by measuring the thickness of the concrete after demolding. However, since the lining thickness is measured after demolding, the lining thickness of concrete can only be indirectly controlled. For this reason, the lining thickness has to be increased excessively, and there is a problem that the amount of concrete used is increased.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to control the lining thickness of the concrete being placed in the cast-in-place lining method.

  In order to achieve the above-described object, the first invention is to excavate a natural ground with a shield excavator while assembling a mold form inside the tail part of the shield excavator so that the mold form and the excavated ground are formed. In forming concrete tunnel by placing concrete between mountains and forming a tunnel, the formwork has an oscillation device and a vibration receiving device using a giant magnetostrictive element, and the oscillation device vibrates. A step (a) of generating a wave, the vibration receiving device receiving the wave, and measuring the lining thickness of the concrete from the arrival time of the wave, and the lining thickness is a target lining thickness And (b) a step of changing the concrete supply amount and the concrete pouring pressure so as to be within the management range.

  Further, the mold is provided with four side plates on the skin plate, a plurality of openings are provided on the skin plate, a gate that can be opened and closed is provided on the opening, and the one side of the skin plate is It is preferable that an oscillation device using a giant magnetostrictive element and a vibration receiving device are provided at a position corresponding to the gate.

  The oscillation device preferably includes a giant magnetostrictive vibrator having a head that can vibrate by a giant magnetostrictive element, and the vibration receiving device preferably includes a sensor.

  The step (a) is reflected by the step of pushing the oscillation device and the vibration receiving device to the concrete, the step of causing the oscillation device to vibrate and generating a wave, and the boundary between the natural ground and the concrete. A step of receiving the wave by the vibration receiving device; and a step of obtaining a lining thickness of the concrete based on the wave, wherein the step (b) includes a lining thickness of the concrete and a target lining thickness. And a step of changing the concrete supply amount and the concrete placing pressure when the lining thickness is outside the control range of the target lining thickness. .

  According to a second aspect of the present invention, while excavating a natural ground with a shield excavator, a mold is assembled in an annular shape inside the tail portion of the shield excavator, and concrete is placed between the mold and the excavated natural ground. In constructing lining concrete and forming a tunnel, a supply means for supplying concrete between the formwork and the excavated ground, a pressing means for pressing the concrete, and the formwork, An oscillation device using a giant magnetostrictive element and a vibration receiving device, wherein the vibration receiving device receives the wave generated by the oscillation device and measures the thickness of the concrete; and the measured concrete thickness Accordingly, a concrete placement system comprising a concrete supply amount of the supply means and a control means for controlling the pressing force of the pressing means.

  According to the present invention, in the cast-in-place lining method, the concrete lining thickness can be controlled in real time during placement.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing a shield excavator 1 that forms a tunnel in the natural ground 19. The shield excavator 1 includes a rotary excavation unit 3 at a front end, and includes a cylindrical tail plate 5 that extends to the rear of the rotary excavation unit 3. A plurality of shield jacks 7 and a press jack 9 are provided along the inside of the tail plate 5. At the rear end of the press jack 9, a wife form frame 11 is provided that can move back and forth along the inner peripheral surface of the tail plate 5.

  The wife formwork 11 is a component that can be moved back and forth by the expansion and contraction of the press jack 9 in a state of blocking between the inside of the tail plate 5 and an inner formwork 13 described later. Moreover, it also has a function as a pressure plate for pressing the concrete 21.

  Further, the shield jack 7 obtains a reaction force from the inner mold 13, and the shield excavator 1 is propelled by the reaction force. Further, concrete 21 is filled between the end form 11, the inner form 13, and the natural ground 19. The concrete 21 is supplied from a remixer (not shown), and is placed from the concrete supply hole 16 of the end form 11 through the placement pump 17 and the concrete supply hose 15. The ring formed by the end form 11 is provided with both the press jack 9 and the concrete supply hole 16, and the concrete supply hole 16 is provided with a concrete supply hose 15. The upper part of FIG. 1 represents the end form 11 that the press jack 9 pressurizes, and the lower part represents the end form 11 provided with the concrete supply hose 15 and the concrete supply hole 16.

  The shield excavator 1 includes a press jack 9 and a end form 11 as concrete pressing means, and a placing pump 17, a concrete supply hose 15, and a concrete supply hole 16 as concrete supply means.

  Note that the tunnel formed by the shield excavator 1 is not limited to a tunnel having a circular cross section, and may be a tunnel having a semi-cylindrical cross section or a horseshoe cross section.

FIG. 2 is a perspective view of the inner mold 13 according to the present embodiment.
The inner mold 13 includes a skin plate 23 and a side plate 25. The skin plate 23 is provided with an oscillation device 29 and a vibration receiving device 27.

  The skin plate 23 is a curved rectangular plate. The skin plate 23 forms a part of an annulus, and is formed into an annular shape and a cylindrical shape by gathering a plurality of inner molds 13. The skin plate 23 is made of steel.

  The side plate 25 is a rectangular plate. The side plates 25 are provided at the four ends of the skin plate 23 to increase the strength of the skin plate 23. The side plate 25 is made of steel.

  The inner mold 13 includes one oscillation device 29 and one vibration receiving device 27. However, in order to improve measurement accuracy, a plurality of vibration receiving devices 27 may be provided for one oscillation device 29. A plurality of pairs of 29 and vibration receiving device 27 may be provided.

  FIG. 3 is a schematic view of the AA cross section of FIG. 2, and a socket 31 having a gate 33 is provided in the opening of the skin plate 23. A screw is provided at the bottom of the socket 31.

  The gate 33 is provided so that the concrete 21 pressed by the end formwork 11 does not leak through the opening of the inner formwork 13, and a gate valve, a cut gate, or the like is used.

  FIG. 4A shows the oscillation device 29. The oscillating device 29 includes a cylindrical casing 37, a nipple 39 formed at an end of the casing 37, and a vibrator 41 and a head 43 that can protrude from the upper portion of the casing 37 by a jack 45.

  The nipple 39 is provided with a screw that can be screwed into the socket 31.

  Moreover, it is not restricted to the fixing by screwing like the nipple 39, The joint for pipes which can join the socket 31 and the casing 37 can be used. For example, a one-touch coupler can be used.

  Further, a packing may be provided between the vibrator 41 and the casing 37 to prevent the concrete 21 from entering the casing 37 when the gate 33 is opened.

  The jack 45 can move the vibrator 41 back and forth, and may be a hydraulic jack or a screw jack. The jack 45 is preferably provided with a stroke meter. This is because, when measuring the lining thickness of concrete, if the head position is different, the propagation distance of the wave is different and the calculated lining thickness changes.

  FIG. 5 is a schematic view of a cross section of the vibrator 41. A giant magnetostrictive element 51 is placed in a coil 49, and a permanent magnet 53 covers the coil 49. The giant magnetostrictive element 51 is connected to a rod 57, and a force is applied to the rod 57 in the major axis direction of the vibrator 41 by a spring 55.

The giant magnetostrictive element 51 is formed of a compound of Tb _0.3 Dy _0.7 Fe _2.0 (terbium-dysprodium-iron). By causing a current to flow through the coil 49 and generating a magnetic field, the giant magnetostrictive element 51 normally extends 0.1% or more in the major axis direction. When the magnetic field from the coil 49 disappears, the original length is restored. The giant magnetostrictive element 51 expands and contracts by repeatedly applying / stopping the current to the coil 49. As the giant magnetostrictive element 51 expands and contracts, the rod 57 reciprocates, and the head 43 vibrates in the direction of the arrow shown in FIG.

  4B shows the vibration receiving device 27. The vibration receiving device 27 is provided with a sensor 47 in a cylindrical casing 37 having a nipple 39 at the tip. 37 can protrude from the top. Further, the vibration receiving device 27 may include a packing and a stroke meter in the same manner as the oscillation device 29.

  The sensor 47 can generally use a vibrometer that can receive the wave generated by the head 43 and reflected by the boundary between the concrete 21 and the rock of the natural ground 19. For example, an accelerometer provided with a piezoelectric element can be used.

  Next, a method of measuring the lining thickness of the concrete 21 using the oscillation device 29 and the vibration receiving device 27 in the inner mold 13 will be described with reference to FIG.

  As shown in FIG. 6A, the oscillation device 29 and the vibration receiving device 27 are attached to the socket 31 of the inner mold 13.

  As shown in FIG. 6B, the nipple 39 of the oscillation device 29 and the vibration receiving device 27 is screwed into the socket 31. The screwing of the nipple 39 and the socket 31 can withstand the pressure of the concrete 21.

  Thereafter, as shown in FIG. 6C, the gate 33 is opened, and the vibrator 41 and the head 43 are projected from the oscillation device 29, and the sensor 47 is projected from the gate 33 from the vibration receiving device 27. At this time, the head 43 and the sensor 47 protrude into the concrete 21 to be equal to or higher than the plane formed by the skin plate 23 so that the wave 59 is not affected by the socket 31 such as being reflected in the socket 31. .

  Thereafter, the vibrator 41 vibrates the head 43 to generate a wave 59 such as a P wave or an S wave. The wave 59 is reflected at the boundary surface and received by the sensor 47 because the propagation speed between the concrete 21 and the natural ground 19 is different. The tip of the head 43 vibrates in a direction compressing the concrete 21 to generate a P wave, and the side surface of the head 43 vibrates in a direction shearing the concrete 21 to generate an S wave.

  Thereafter, as shown in FIG. 6D, the vibrator 41 is housed in the casing 37 of the oscillation device 29, the sensor 47 is housed in the casing 37 of the vibration receiving device 27, and the gate 33 is closed.

  Thereafter, as shown in FIG. 6 (e), the oscillation device 29 and the vibration receiving device 27 are removed from the inner mold 13. The oscillation device 29 and the vibration receiving device 27 may be removed from the inner mold 13 for which the lining thickness measurement has been completed or the inner mold 13 with the concrete 21 hardened, and installed in another inner mold 13. .

  In measuring the concrete lining thickness, it is also possible to measure without pushing the vibrator 41 or the sensor 47 into the concrete 21. When measuring without pushing, it is not necessary to provide the jack 45 to the oscillation device 29 and the vibration receiving device 27. Also in the measurement method, the pushing process and the pulling back process of the vibrator 41 and the sensor 47 are not necessary.

  An example of a method for calculating the lining thickness using vibration receiving data is introduced. Using the received vibration data received by the sensor 47, the arrival time of the direct wave and the arrival time of the reflected wave are calculated. Here, since the distance between the oscillation device 29 and the vibration receiving device 27 is known, the propagation speed of the wave in the concrete 21 can be calculated from the arrival time of the direct wave. Therefore, the lining thickness can be calculated from the propagation speed and the arrival time of the reflected wave.

  In this measurement method, an S-wave having a shorter wavelength than that of a conventional ultrasonic generator can be generated by an oscillator using a giant magnetostrictive element.

  Further, in this measurement method, it is possible to contact the concrete before demolding and the oscillation device, which have been difficult in the past, without interposing a metal inner mold frame between them.

  In addition, the present measurement method provides an inner mold that allows the oscillation device and the vibration receiving device to be taken in and out while withstanding the pressure of the pressurized concrete.

  That is, in this measurement method, it is possible to measure the lining thickness of uncured concrete before demolding in the cast-in-place lining method, which has been difficult to measure conventionally.

  Then, the placement method of the concrete 21 is demonstrated using FIG.

  As shown in FIG. 7A, the shield jack 7 is contracted to secure a space for inserting the inner mold 13d in a space adjacent to the inner mold 13c.

  As shown in FIG. 7B, an inner mold 13d is installed between the shield jack 7 and the inner mold 13c.

  As shown in FIG. 7C, the concrete supply hose 15 starts placing concrete 21 on a portion surrounded by the inner mold 13, the wife mold 11, and the natural ground 19. The wife form frame 11 moves to the left in the figure as the concrete 21 is placed while being applied with a certain pressure by the press jack 9.

  As shown in FIG. 7D, after the end form 11 passes through a portion where the oscillation device 29 and the vibration receiving device 27 are present, the thickness of the concrete 21 is measured by the method shown in FIG. Further, based on the measured thickness, the pressure applied by the press jack 9 to the end form 11 and the amount of the concrete 21 supplied by the concrete supply hose 15 are controlled.

  As shown in FIG. 7 (e), when the end form 11 reaches the end of the inner form 13d, the shield jack 7 is contracted again to secure a space for the next inner form 13 to enter. That is, the state returns to the state of FIG.

  By repeating the process shown in FIG. 7, the shield excavator 1 is dug, concrete is placed, and a tunnel lining is formed.

  In the cast-in-place lining method, the inner mold 13 is removed from the hardened concrete 21, moved forward, and assembled into a shield.

  FIG. 8 is a diagram illustrating the control device 61 according to the present embodiment. The control device 61 can send an oscillation command to the oscillation device 29 and can receive vibration receiving data from the vibration receiving device 27. Further, it is possible to control the supply speed of the concrete 21 by controlling the rotation speed of the placing pump 17, and to control the placing pressure of the concrete 21 by controlling the pressure of the press jack 9.

  For example, the control device 61 is a computer, and includes, for example, a calculation unit, a storage unit, a communication unit, an input unit, a display unit, and the like.

  The calculation means calculates a lining thickness from vibration receiving data and executes a control flow to be described later. The storage means stores vibration receiving data, measured lining thickness, management value and management range, which will be described later, a program for executing a control method, and the like.

  The communication means performs communication such as transmitting an oscillation command to the oscillating device 29, receiving wave vibration data from the vibration receiving device 27, and transmitting a setting value change to the placing pump 17 and the press jack 9.

  The input means inputs a management value and a management range manually or automatically. Further, the display means displays information such as the current rotation speed of the placing pump 17, the pressure of the press jack 9, the lining thickness of the concrete 21, and the vibration receiving data.

  The control device 61 may control not only the lining thickness of the concrete 21 but also the shield excavation speed, the face pressure of the shield, the amount of excavated soil, and the presence / absence of a gap at the top end Such data may be collected.

  When the casting pressure is increased, the lining thickness of the concrete 21 increases. This is because the concrete 21 bites into the natural ground 19 due to an increase in the pouring pressure. On the other hand, when the placing pressure is lowered, the concrete 21 is thinned by the soil water pressure from the natural ground 19.

  Further, when the pouring pressure is increased, the amount of concrete 21 necessary for the pouring is increased, so that it is necessary to increase the rotation speed of the pouring pump 17 and increase the supply amount of the concrete. On the contrary, if the driving pressure is lowered, it is necessary to reduce the rotation speed of the driving pump 17.

  FIG. 9 is a flowchart illustrating a control method performed by the control device 61. First, the management range of the lining thickness is set (step 101). As a management range setting method, “design thickness” + “excavation” is set as a management value, and a certain range is provided above and below the management value. For example, if the design thickness is 30 cm, the surplus depth is 2 cm, and the fixed range is ± 0.5 cm, the management range is 31.5 cm to 32.5 cm.

  Thereafter, the concrete lining thickness is measured by the method described in FIG. 6 (step 102). Next, the measured thickness is compared with the maximum value of the management range (step 103), and when the measured thickness is larger than the maximum value of the management range, the setting pressure for driving (linked with the pressure setting of the press jack 9) and The placement setting flow rate is lowered (as a result, the setting rotational speed of the placement pump 17 is lowered) (step 105). Next, the measured thickness and the minimum value of the management range are compared (step 104). If the measured thickness is smaller than the minimum value of the management range, the setting pressure and the setting flow rate are increased (step 106). . If the measured thickness is within the control range, the set value is not changed and the process returns to the next measurement.

  In step 105, the set pressure of the press jack 9 may be automatically changed by a fixed value such as 0.01 MPa, or may be automatically changed by a fixed rate such as 5% of the current value. Further, the amount of change may be determined manually. The setting rotational speed of the driving pump 17 may be changed in the same manner, and may be changed in the same way in step 106.

  Further, the lining thickness of the concrete 21 after curing is measured by a known method or the like, the lining thickness after curing is compared with the lining thickness before curing obtained by this measuring method, and the management It is preferable to change the value.

  According to this embodiment, the lining thickness of uncured concrete is measured, and the lining thickness of concrete being placed is directly controlled by changing the placement amount and supply amount of concrete in real time. it can.

  According to this embodiment, a concrete lining having a sound lining thickness can be reliably performed. The lining can be performed without excessively increasing the lining thickness and using the concrete excessively, and without lowering the lining thickness below the design thickness.

  In addition, according to the present embodiment, it is possible to construct without applying extra pressure to the concrete, so even in a portion where the earth covering is thin, the earth covering is not deformed and the ground is not raised or submerged. That's it.

  While the preferred embodiments of the concrete placing method and the placing system according to the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

The figure which shows the outline | summary of the shield excavator 1 which concerns on this Embodiment. The figure which shows the internal mold 13 which has the oscillation apparatus 29 and the vibration receiving apparatus 27 based on this Embodiment. The figure which shows the cross section of the inner mold frame 13 which concerns on this Embodiment. The figure which shows the oscillation apparatus 29 and the vibration receiving apparatus 27 which concern on this Embodiment. FIG. 4 is a schematic view of a cross section of a vibrator 41 according to the present embodiment. The figure which shows the measuring method of the lining thickness of the concrete 21 which concerns on this Embodiment. The figure which shows the measuring method of the lining thickness of the concrete 21 which concerns on this Embodiment. The figure which shows the measuring method of the lining thickness of the concrete 21 which concerns on this Embodiment. The figure which shows the measuring method of the lining thickness of the concrete 21 which concerns on this Embodiment. The figure which shows the measuring method of the lining thickness of the concrete 21 which concerns on this Embodiment. The figure which shows the placement method of the concrete 21 which concerns on this Embodiment. The figure which shows the control apparatus 61 which concerns on this Embodiment. The flowchart of the lining thickness control of the control apparatus 61 which concerns on this Embodiment.

Explanation of symbols

1 ……… Shield excavator 3 ……… Rotating cutting part 5 ……… Tail plate 7 ……… Shield jack 9 ……… Press jack 11 ……… Wife mold 13 ……… Inner mold 15 ……… Concrete supply hose 16 ……… Concrete supply hole 17 ………… Place pump 19 ……… Machiyama 21 ……… Concrete 23 ……… Skin plate 25 ……… Side plate 27 ……… Vibration device 29 ……… Oscillation Device 31 ......... Socket 33 ......... Gate 37 ......... Case 39 ......... Nipple 41 ......... Vibrator 43 ......... Head 45 ......... Jack 47 ......... Sensor 49 ... …… Coil 51 ... ... Super magnetostrictive element 53 ......... Permanent magnet 55 ......... Spring 57 ... …… Rod 59 ......... Wave 61 ......... Control device

Claims (5)

While excavating the natural ground with a shield excavator, the formwork is assembled in an annular shape inside the tail part of the shield excavator, and concrete is placed between the formwork and the excavated natural ground to provide lining concrete. In building and forming a tunnel,
The mold has an oscillation device and a vibration receiving device using a giant magnetostrictive element,
(A) measuring the lining thickness of the concrete from the arrival time of the wave, the vibration receiving device receiving the wave, the oscillation device vibrates to generate a wave;
A step (b) of changing the concrete supply amount and the concrete placing pressure so that the lining thickness falls within the control range of the target lining thickness;
A concrete placement control method comprising: The formwork is
There are 4 side plates on the skin plate,
The skin plate is provided with a plurality of openings,
A gate that can be opened and closed is provided in the opening,
The concrete placement control method according to claim 1, wherein an oscillation device using a magnetostrictive element and a vibration receiving device are provided at a position corresponding to the gate on one side of the skin plate. The oscillation device includes a giant magnetostrictive vibrator having a head that can vibrate by a giant magnetostrictive element,
The concrete placement control method according to claim 2, wherein the vibration receiving device includes a sensor. The step (a)
A step in which the oscillation device vibrates to generate a wave;
The vibration receiving device receiving the wave reflected by the boundary between the natural ground and the concrete; and
A step of determining a lining thickness of the concrete based on the wave;
With
The step (b)
Comparing the concrete lining thickness with the target lining thickness;
When the lining thickness is outside the control range of the target lining thickness, the step of changing the concrete supply amount and the concrete placement pressure;
The concrete placement control method according to claim 1, further comprising: While excavating the natural ground with a shield excavator, the formwork is assembled in an annular shape inside the tail part of the shield excavator, and concrete is placed between the formwork and the excavated natural ground to provide lining concrete. In building and forming a tunnel,
Supply means for supplying concrete between the formwork and the excavated ground;
Pressing means for pressing the concrete;
The mold has an oscillation device and a vibration receiving device using a giant magnetostrictive element, and the vibration receiving device receives a wave generated by vibration generated by the oscillation device and measures the thickness of the concrete. When,
A concrete placement system comprising: a concrete supply amount of the supply means and a control means for controlling the pressing force of the pressing means according to the measured concrete thickness.

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