JP2014009545A - Plastic fluidity evaluation method of excavated soil in chamber in earth pressure type shield construction method, and earth pressure type shield excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively obtain and evaluate the plastic fluidity of excavated soil in a chamber, in an earth pressure shield construction method.SOLUTION: Earth pressure gauges for measuring the earth pressure of excavated earth at a plurality of positions in a chamber are installed at positions near passing loci of stirring blades, respectively. An index value which becomes an indication of variation situation of the earth pressure when the stirring blade passes near the earth pressure gauge is obtained from a measured value measured by each of the earth pressure gauges, and the plastic fluidity of the excavated earth at the plurality of positions in the chamber is evaluated on the basis of the index values. Measurement results are handled as waveform data and the index value is obtained on the basis of the variation situation of the waveform data. A deviation earth pressure and/or Fourier amplitude is used as the index value. Evaluation results are visually displayed in a display of a management computer. The management computer is provided as management means for calculating the index value from the measured value of the earth pressure gauge and evaluating/displaying the plastic fluidity.

Description

  The present invention relates to an earth pressure shield method, and more particularly to an evaluation method for evaluating plastic fluidity of excavated soil in a chamber during excavation, and an earth pressure shield excavator for performing the evaluation method.

  As is well known, the earth pressure type shield method uses hydrostatic bentonite and polymer for the excavated soil taken into the chamber using an earth pressure type shield excavator provided with a chamber for taking the excavated soil behind the cutter device. By adding a chemical solution such as material or bubbles and stirring with a stirring blade, the excavated soil has a predetermined plastic fluidity, and the earth pressure is applied to the face to perform excavation while maintaining the face stably. It is a construction method based on this.

  In such earth pressure type shield method, it is important to apply the earth pressure by the excavated soil uniformly and stably to the entire face of the face, so that the plastic fluidity of the excavated soil in the chamber is appropriately set and It needs to be kept stable. For this purpose, it is necessary to sequentially check whether the excavated soil is uniformly plasticized in the entire chamber during excavation, and Patent Document 1 proposes a method for that purpose.

  In the method disclosed in Patent Document 1, a rotating flapper type measuring device is provided so as to protrude into a chamber, and the measuring device receives from the excavated soil by measuring the rotational torque when the measuring device is rotated in the excavated soil. The plastic fluidity of the excavated soil (that is, the condition of the excavated soil) is evaluated based on the resistance force.

JP 2007-191878 A

In the above conventional method, the plastic fluidity of the excavated soil in the chamber during excavation can be directly grasped and managed in real time, but the measuring device is always subject to resistance from the excavated soil, and thus frequently fails. In that respect, it is not practical and has not become widespread.
Further, since it is necessary to provide the measuring device so as to protrude into the chamber, the installation position thereof is restricted, and usually one of the outermost peripheral portions in the chamber is not interfered with the rotation of the cutter device or the stirring blade. Therefore, it is difficult to grasp the entire plastic fluidity in the chamber over a wide range.

  As described above, at present, an effective and appropriate method for accurately and extensively evaluating the plastic fluidity of excavated soil in the chamber has not been established, and it is necessary to develop an effective and appropriate means to enable it. It is said that it is the actual situation.

  In view of the above circumstances, the invention according to claim 1 stabilizes the face by stirring the excavated soil with a stirring blade in the chamber to impart plastic fluidity, and applying the earth pressure of the excavated soil to the face. A method for evaluating the plastic fluidity of excavated soil in a chamber in an earth pressure shield method for evaluating the plastic fluidity of the excavated soil in the chamber, which is applied to an earth pressure shield method of performing excavation, A plurality of earth pressure gauges for measuring the earth pressure of the excavated soil at a plurality of locations are respectively installed in the vicinity of the passage trajectory of the agitating blade, and the agitating blade is measured by the earth pressure gauge from the earth pressure gauge. Each of the index values to be an index of the earth pressure fluctuation status when passing through a nearby position, and based on those index values, the above-mentioned at a plurality of locations in the chamber And evaluating the plastic flow of Kezudo.

  Invention of Claim 2 is the evaluation method of invention of Claim 1, Comprising: The earth pressure measurement by the earth pressure gauge is performed momentarily at a predetermined sampling time, the measurement result is handled as waveform data, The index value is obtained based on the fluctuation state of the waveform data.

  Invention of Claim 3 is the evaluation method of invention of Claim 2, Comprising: The deviation earth pressure calculated | required by removing the influence of the earth removal and excavation from the waveform data as the index value, and / or A Fourier amplitude obtained by Fourier analysis from the deviation earth pressure is used.

  Invention of Claim 4 is the evaluation method of invention of Claim 3, Comprising: The index value in the arbitrary positions in the said chamber, the said index value in the position of the said earth pressure gauge, the said earth pressure gauge, and the said arbitrary Calculated based on the distance to the position of the position and obtained as an estimated value, based on the estimated value, evaluate the plastic fluidity of the excavated soil in the entire chamber, and visualize the result on the display of the management computer It is characterized by displaying.

  The invention according to claim 5 is configured to perform excavation while stabilizing the face by agitating the excavated soil with a stirring blade in the chamber to impart plastic fluidity and applying the earth pressure of the excavated earth to the face. A soil pressure type shield excavator, wherein a plurality of earth pressure gauges for measuring the earth pressure of the excavated soil at a plurality of locations in the chamber are respectively installed in the vicinity of the passage trajectory of the stirring blade, and the earth pressure gauge From the measured values, index values serving as indices of fluctuations in earth pressure when the agitating blades pass near the earth pressure gauge are obtained, and the excavated soil at a plurality of locations in the chamber is obtained based on the index values. It is characterized by comprising management means for evaluating and displaying the plastic fluidity.

According to the present invention, since the fluctuation state of the earth pressure when the agitating blade passes through the position near the earth pressure gauge reflects the hard and soft state of the excavated earth, that is, the plastic fluidity, the measured value from the earth pressure gauge at that time It is possible to effectively grasp and evaluate the plastic fluidity of excavated soil at that position.
Therefore, according to the present invention, the measuring device frequently fails as in the case of the conventional method shown in Patent Document 1 (when the plastic fluidity of excavated soil is directly measured by the measuring device protruding into the chamber). It is possible to install multiple earth pressure gauges in the chamber without hindrance, and it is possible to grasp and evaluate the plastic fluidity of the entire chamber over a wide range. It is possible to excavate while performing proper construction management.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows an embodiment of the present invention, in which (a) is a side view showing a schematic configuration of a tip portion of the earth pressure shield excavator of the present embodiment, and (b) is a front view (viewed along line bb in (a)). (Cross sectional view), (c) is an enlarged view of the main part for showing the positional relationship between the earth pressure gauge and the stirring blade. FIG. 4 is an explanatory diagram of the principle of the present invention, (a) is a diagram showing waveform data as a measurement value by a soil pressure gauge, and (b) is a deviation soil excluding the influence of jack thrust and soil removal from the waveform data. It is a figure which shows a pressure. FIG. 4 shows index values in the present invention, where (a) shows a deviation earth pressure and (b) shows a Fourier amplitude. It is explanatory drawing about the calculation method for estimating the index value of arbitrary points similarly. It is a figure which shows the example of the visualization display pattern to a management computer.

Hereinafter, with reference to FIGS. 1-5, embodiment of the plastic fluidity | liquidity evaluation method of the excavation soil in a chamber in the earth pressure type shield method of this invention and earth pressure type shield method will be described.
1A to 1C show a schematic configuration of an earth pressure shield excavator used for applying the evaluation method of the present embodiment.
This is basically the same as the earth pressure type shield excavator used in the normal earth pressure type shield construction method, as shown in FIG. The chamber 3 is provided, and the excavated soil generated by excavating the face by the cutter device 4 is taken into the chamber 3, and a chemical solution such as hydrobentonite or a polymer material or bubbles is added to the excavated soil in the chamber 3. The excavated soil is given a predetermined plastic fluidity by stirring and the earth pressure is applied to the face so that the excavation is performed while stabilizing the face.

  In this embodiment, the excavated soil in the chamber 3 is agitated by the agitating blade 5 provided on the back of the cutter device 4, and the excavation in the chamber 3 is performed in the vicinity of the rotation trajectory of the agitating blade 5. The earth pressure gauges 6 for measuring the earth pressure of the soil are installed at a plurality of locations, and the plastic flow of the excavated earth in the chamber 3 is performed by a management computer (management means) (not shown) based on the measured values by the earth pressure gauges 6. Excavation is performed while evaluating and displaying the sex.

That is, as shown in (a), the stirring blades 5 (in the present embodiment, the two stirring blades 5 of the two agitating blades 5) are respectively disposed on both sides of the outer peripheral edge of the back of the cutter device 4 with the axis serving as the center of rotation. Since the shape and the installation position are different, in order to distinguish them, one is set as a stirring blade 5a and the other is set as a stirring blade 5b). The agitating blade 5 moves while drawing a circular rotation trajectory in the chamber 3, thereby agitating the excavated soil in the chamber 3.
The installation positions of the stirring blades 5 may be arbitrarily set so that an efficient stirring effect on the excavated soil can be obtained in the entire chamber 3, and as long as the rotation locus of both the stirring blades 5 is matched ( That is, it may be installed at a position equidistant from the shaft center). However, it is more preferable to slightly shift both positions in the radial direction because it can stir over a wide range. In the illustrated example, as shown in (a), the other stirring blade 5b is installed slightly outside in the radial direction from one stirring blade 5a.

Then, as shown in (a), a plurality of earth pressure gauges 6 for measuring the earth pressure of the excavated soil agitated in the chamber 3 are respectively agitated in the partition wall 2 defining the chamber 3. The agitating blades 5 installed at positions near the trajectory of the blades 5 and at the back of the cutter device 4 as the cutter device 4 rotates are located near the respective earth pressure gauges 6 as shown in FIG. It is supposed to pass by itself.
In the illustrated example, as shown in (b), the earth pressure gauge 6 is installed at a position where the virtual circle that is the rotation trajectory of the stirring blade 5 is equally divided into six equally in the circumferential direction. The earth pressure gauges 6 are distributed at almost equal intervals so as to form a circle with respect to a total of six places, two places each at the bottom and the middle in the height direction.

In this embodiment, the earth pressure of the excavated earth in the chamber 3 is measured at each point by each earth pressure gauge 6, and the earth when the agitating blade 5 passes the position near each earth pressure gauge 6 from these measured values. Index values that are indicators of the pressure fluctuation state are obtained, and the plastic fluidity of the excavated soil in the entire chamber 3 is evaluated based on these index values.
In particular, in the present embodiment, earth pressure measurement by the earth pressure gauge 6 at the time of excavation is carried out almost continuously at a predetermined sampling time (for example, at intervals of 0.25 seconds), the measurement result is handled as waveform data, and the waveform data A management computer (not shown) as a management means for obtaining deviation earth pressure and Fourier amplitude as index values based on the fluctuation state and evaluating plastic fluidity on the basis of the deviation earth pressure and Fourier amplitude. ).

The principle of the present invention will be described with reference to FIGS.
The average earth pressure in the entire chamber 3 measured by the earth pressure gauge 6 greatly increases due to the influence of jack thrust during excavation, and greatly decreases when the earth is discharged from the chamber 3. The measurement value obtained by measuring almost continuously with a very short sampling time as described above basically exhibits a waveform that repeatedly rises and falls as shown in FIG. 2 (a). .

With respect to such a basic waveform, when the agitating blade 5 passes a position in the vicinity of an arbitrary earth pressure gauge 6, there is an effect that the excavated soil is pressed against the nearest earth pressure gauge 6 by the agitating blade 5. In response, the measured value by the earth pressure gauge 6 temporarily rises slightly.
The degree of increase in earth pressure at that time is not always constant, and varies depending on the plastic fluidity of the excavated soil at the position near the earth pressure gauge 6, and the excavated soil has low plastic fluidity (excavation) The measured value rises remarkably when the soil is hard and difficult to flow), but the measured value does not increase so much when the plastic fluidity is high (when the excavated soil is soft and flows sufficiently). is there.

  Therefore, the present invention eliminates the effects of jack thrust and soil removal from the waveform data as the measured value of the earth pressure gauge 6 as shown in FIG. Data on the deviation earth pressure as shown in (b) is obtained (specifically, the total earth pressure average value may be subtracted from the measured value of the earth pressure gauge 6).

  The deviation earth pressure data has a peak every time the stirring blade 5 passes, and there is a clear correlation between the magnitude of the peak and the hardness of the excavated soil as shown in FIG. Yes (as described above, the peak value increases as the excavated soil is harder, and decreases as the excavated soil is softer). Therefore, the hardness value of the excavated soil, that is, plastic fluidity, is grasped using the peak value in this deviation soil pressure data as an index value. And can be evaluated.

  Further, Fourier analysis is further performed on the above-mentioned data of the earth pressure, and a power spectrum for showing the characteristics of earth pressure fluctuation in relation to the period is obtained, and the power spectrum is shown in FIG. 3B. If such Fourier amplitude is obtained, the Fourier amplitude data also has a peak corresponding to the hardness of the excavated soil when the stirring blade 5 passes through. Therefore, this data is also the plastic fluidity of the excavated soil in the chamber 3. Can be used as an index value, and plastic fluidity can be evaluated from this.

  Therefore, according to the present embodiment, the deviation earth pressure data shown in FIG. 3A and / or the Fourier amplitude data shown in FIG. 3B are used as index values (in other words, deviation earth pressure and Fourier amplitude). ) Qualitative and quantitative relationship between the peak value in the deviation earth pressure and Fourier amplitude as the index value and the plastic fluidity as an index value in advance or theoretically If obtained, it is possible to grasp and evaluate the plastic fluidity of the excavated soil at the position of each earth pressure gauge 6 in the chamber 3 at the time of excavation from the index value by the management computer. Can be effectively used for construction management.

  In the case of the evaluation method of this embodiment, the earth pressure gauge only needs to be installed facing the chamber 3, so that the measurement apparatus frequently fails as in the case of the conventional method shown in Patent Document 1. In addition, since it is possible to install a plurality of (many) earth pressure gauges 6 at a desired position in the chamber 3 without hindrance, it is possible to evaluate the plastic fluidity of the entire chamber 3 over a wide range. In that respect, it is much more effective than the conventional method.

In order to evaluate the plastic fluidity of the excavated soil in the entire chamber 3 by the evaluation method of the present embodiment, it is naturally preferable to set as many earth pressure measurement points as possible with the earth pressure gauge 6. However, since it is not realistic to install too many earth pressure gauges 6, it is practical to have about 6 places as in the above embodiment, or even at least about 4 places in the chamber 3. It is possible to grasp and evaluate the entire plastic fluidity to a practical level.
Moreover, in this embodiment, since it is based on detecting the earth pressure fluctuation | variation when the stirring blade 5 passes, the installation position of the earth pressure gauge 6 shall be as close as possible to the passage position of the stirring blade 5 Of course, it is preferable that the position of the earth pressure gauge 6 is not strictly defined as long as the fluctuation of the earth pressure when the stirring blade 5 passes can be detected significantly.
In any case, the sampling time of the data by the earth pressure gauge 6 is preferably very short so as to obtain substantially continuous waveform data (for example, about 0.25 second intervals as in the above embodiment) What is necessary is just to set arbitrarily, as long as data required in construction management can be collected.

  Furthermore, in order to grasp and evaluate the plastic fluidity in the whole chamber 3 more intuitively, the index value at an arbitrary position is estimated by the following method based on the index value at the installation position of the earth pressure gauge 6. It is preferable to estimate and evaluate the plastic fluidity not only in the installation position of the earth pressure gauge 6 but also in the entire chamber 3.

That is, in this embodiment, as shown in FIG. 4, the index value at each point obtained by actually calculating the estimated value Vp of the index value at an arbitrary point P in the chamber 3 based on the measured value of the earth pressure gauge 6. Based on V1 to V6 and distances L1 to L6 between the installation position of the earth pressure gauge 6 and an arbitrary point P, it can be obtained by calculation according to the equation (1).
The coefficients α _{1 to} α ₆ in the equation (1) are weighting coefficients indicating the degree of influence from the index values V _{1 to} V _{6 at} the position of the earth pressure gauge 6 with respect to an arbitrary point P. These coefficients α _{1 to} α ₆ are Each is obtained by equation (2). The index n in equation (2) may be n = 1, but n = 2 or n = 3 may be used when the influence of distance is more important.

Then, the point P is set at many points throughout the chamber 3, and index values at these points are respectively obtained as estimated values Vp (for this purpose, L1 to L6 corresponding to the positions (coordinates) of each point. (2) and (1) can be repeated using the value of the parameter as a parameter), and the results are visualized and displayed on the display of the management computer every moment, so that the operator can visually monitor the display, and the chamber 3 It is possible to intuitively and easily evaluate the plastic flow state of the entire inside, and it is possible to perform appropriate construction management based on it.
In this case, the form of visualization display on the display is arbitrary. For example, as shown in FIG. 5, it is conceivable that the region indicating the chamber 3 is displayed by color according to the plastic fluidity or displayed in different shades. . Specifically, for example, an area where the excavated soil is excessively hard is displayed in red, an excessively soft area is displayed in blue, an appropriate area is displayed in white, or an area with poor plastic fluidity is displayed in a darker area with a higher density. It is also possible to do this.

  Although the embodiment of the present invention has been described above, the above embodiment is merely a preferable example, and the present invention is not limited to the above embodiment, and a specific method of the evaluation method of the present invention, for example, Specific calculation method for calculating the index value from the measured value of the earth pressure gauge, specific evaluation method and display method for evaluating and displaying the plastic fluidity based on the index value, and the evaluation method of the present invention As for the specific configuration of each part of the earth pressure shield excavator used for carrying out the above, it is natural that appropriate design changes and applications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Skin plate 2 Bulkhead 3 Chamber 4 Cutter apparatus 5 Stirring blade 6 Earth pressure gauge

Claims (5)

The excavated soil is agitated by a stirring blade in a chamber to give plastic fluidity, and is applied to an earth pressure type shield method for excavating while stabilizing the face by applying the earth pressure of the excavated soil to the face. A method for evaluating the plastic fluidity of the excavated soil in
A plurality of earth pressure gauges for measuring the earth pressure of the excavated soil at a plurality of locations in the chamber are respectively installed in the vicinity of the passing trajectory of the stirring blades, and the stirring blades are determined from the measured values by the earth pressure gauges. An index value serving as an index of the fluctuation state of earth pressure when passing through a position near the earth pressure gauge is obtained, and the plastic fluidity of the excavated soil at a plurality of locations in the chamber is evaluated based on the index value. A method for evaluating the plastic fluidity of excavated soil in a chamber in the earth pressure type shield method.   The earth pressure is measured by the earth pressure gauge every moment at a predetermined sampling time, the measurement result is handled as waveform data, and the index value is obtained based on the fluctuation state of the waveform data. The plastic fluidity | liquidity evaluation method of the excavation soil in a chamber in the earth pressure type shield construction method of 1 description.   The deviation earth pressure obtained by excluding the influence of soil removal and excavation from the waveform data and / or the Fourier amplitude obtained by Fourier analysis from the deviation earth pressure is used as the index value. The plastic fluidity | liquidity evaluation method of the excavation soil in a chamber in the earth pressure type shield construction method of 2 description.   An index value at an arbitrary position in the chamber is calculated based on the index value at the position of the earth pressure gauge and a distance between the earth pressure gauge and the arbitrary position, and is obtained as an estimated value. 4. The excavated soil in the chamber in the earth pressure shield method according to claim 3, wherein the plastic fluidity of the excavated soil in the entire chamber is evaluated based on the value, and the result is visualized on a display of a management computer. Plastic fluidity evaluation method. An earth pressure shield excavator configured to perform excavation while stabilizing the face by agitating the excavated soil with a stirring blade in the chamber to impart plastic fluidity and applying the earth pressure of the excavated earth to the face. ,
A plurality of earth pressure gauges for measuring the earth pressure of the excavated soil at a plurality of locations in the chamber are installed in the vicinity of the passing trajectory of the stirring blade, respectively, and the stirring blade is measured by the earth pressure gauge based on the measured value by the earth pressure gauge. Each index value that is an index of the fluctuation state of earth pressure when passing through a position near the pressure gauge is obtained, and the plastic fluidity of the excavated soil at a plurality of locations in the chamber is evaluated and displayed based on the index values. The earth pressure type shield excavator characterized by comprising the management means for this.

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