JP7401394B2 - How to predict the final displacement of a tunnel - Google Patents

Description

The present invention relates to a method for accurately predicting the final displacement amount of a tunnel, such as the inner space displacement amount and the crown settlement amount.

For example, in the construction of mountain tunnels, typified by the NATM construction method, various types of surveying are performed in order to construct the tunnels with high precision and high quality. Surveying items include, for example, shoring inspection that measures the top, left and right three points of a steel shoring to confirm installation accuracy, hit surveying that measures hit at any cross section or arbitrary point after excavation, and crown surveying. There are underground A measurements that measure the amount of subsidence and internal space displacement, and cross-sectional measurements that measure an arbitrary cross section of the internal space of an excavation.

Among these various survey items, the underground A measurement is carried out at regular intervals (for example, at intervals of 10 to 30 m) in the tunnel extension direction. Among underground A measurements, measuring the amount of crest subsidence involves measuring the change in absolute height and elevation at the same location at the top of the tunnel due to excavation, and by understanding the amount and rate of subsidence at the top of the tunnel, safety of the tunnel can be improved. The purpose of this measurement is to obtain data for determining the stability and effectiveness of shoring.Measurement of internal displacement is used to confirm the stability of the tunnel and the effectiveness of shoring, determine the timing of shoring construction, and perform lining work. The purpose is to obtain materials for determining the establishment date, etc.

The surveying work for the underground A measurement is carried out by installing a total station 51 inside the tunnel 50, as shown in FIG. This is done by measuring the quasi-targets 52, 52... (five points: the top, left shoulder, lower left half, right shoulder, lower right half) and managing the amount of displacement and sinking of each point.

On the other hand, as part of tunnel construction management, the final displacement amount of the tunnel is predicted based on the underground A measurement. The most frequently used method is to accumulate correlation data between the initial displacement rate in underground A measurement (often the rate of progress of displacement one day after the start of measurement or the rate of progress of displacement up to the 1D displacement amount) and the final displacement amount. If the initial displacement rate is measured by the A measurement in the pit after excavation, the final displacement amount is predicted from the correlation data.

As related to this technology, Patent Document 1 below describes a cable that is stretched with a constant tension between two predetermined measurement points, and a cable that is installed at one of the two measurement points and A ground deformation measurement device comprising: means for detecting the amount of movement of the detector; and arithmetic processing means for determining the displacement speed of each measurement point from the amount of movement detected by the detection means and calculating the final displacement amount based on this displacement speed. is disclosed.

Furthermore, in Patent Document 2 listed below, a displacement management level is set stepwise from a predetermined maximum displacement amount, and the final displacement amount corresponding to the displacement management level is determined based on the elapsed period after the start of measurement and the amount of displacement in the tunnel. A control curve for inner space displacement during tunnel excavation is set by calculation using a function curve with the parameters as parameters, and a displacement prediction curve is determined using the function curve based on the initial displacement speed obtained immediately after the start of excavation. A method for predicting displacement inside a tunnel is disclosed, which predicts the amount of displacement.

Japanese Patent Application Publication No. 7-159106 Japanese Unexamined Patent Publication No. 7-197785

However, in the above-mentioned method for predicting the final displacement amount, it is desirable to measure the displacement amount (initial displacement speed) immediately after excavation. After the installation of the shoring and the secondary spraying, the process starts when the collimation target (optical prism) is installed on the wall, so some time has already elapsed from the time of blasting to the initial measurement, which can lead to errors. There was a problem with this being a factor. As a result, errors occurred in predicting the final amount of displacement, which often resulted in situations in which it was not possible to secure the thickness of the concrete lining, or in many cases, resewing (re-excavation) was forced.

Therefore, the main object of the present invention is to provide a method for predicting the final amount of displacement with higher accuracy than before, based on the initial displacement speed determined from displacement measurement, in the construction of mountain tunnels.

In order to solve the above problem, the present invention according to claim 1 provides a method for predicting the final displacement amount based on the initial displacement speed obtained from displacement measurement in the construction of a mountain tunnel, comprising:
After blasting, the tunnel wall surface is first sprayed, then steel shoring is installed, and the installation position of the steel shoring is measured by measuring the sighting target attached to the steel shoring. A first step of continuously measuring the displacement of the steel shoring after performing the shoring inspection to be performed;
After completing the secondary spraying, the second step is to set up a collimation target on the tunnel wall and start the underground A measurement.
Based on the displacement measurement of the steel shoring and the displacement measurement by the underground A measurement, an initial displacement speed that takes into account the amount of displacement of the steel shoring is calculated, and an initial displacement rate is calculated based on the accumulated data. A method for predicting the final displacement of a tunnel is provided, which is characterized by comprising a third step of predicting the final displacement from correlation data between the displacement speed and the final displacement.

In the invention according to claim 1, first, a shoring inspection is performed to measure the installation position of the steel shoring, and then displacement measurement of the steel shoring is continuously performed. (First step). Then, as usual, after finishing the secondary spraying, if a collimation target is installed on the tunnel wall and the underground A measurement is started (second step), the displacement measurement of the steel shoring and the underground A Based on the displacement measurement, the initial displacement rate is calculated taking into account the displacement of the structural steel support, and the final displacement rate is calculated from the correlation data between the initial displacement rate and the final displacement created based on the accumulated data. The amount of displacement is predicted (third step).

In the present invention, the displacement of the steel shoring is measured at an earlier stage than normal underground A measurement, that is, from the stage when the steel shoring is installed, and the displacement of the steel shoring is measured based on the displacement measurement by the underground A measurement. The initial displacement speed is calculated by taking into account the displacement amount of the workpiece. The amount of displacement of the tunnel ground after blasting shows a tendency to be large at the beginning and gradually converge. However, underground A measurements could only be started after the secondary spraying was completed and a collimation target was installed on the tunnel wall, and measurements were taken only after the displacement had begun to converge to a certain extent. As a result, the correlation between the initial displacement speed and the final displacement amount was weakened accordingly, so in the present invention, in order to start measuring the tunnel displacement amount from the earliest possible stage, after the steel shoring was installed, Since the displacement of the steel shoring is measured and the initial displacement rate is calculated by adding this value to the measured value of the underground A measurement, the correlation between the initial displacement rate and the final displacement amount can be improved, and the final displacement rate can be improved. It becomes possible to predict the amount of displacement with high accuracy.

As the present invention according to claim 2, the initial displacement speed is defined as α (days) from the start of displacement measurement of the steel shoring to the start of A measurement, and D as the displacement amount of the steel shoring after this α has elapsed. The final value of the tunnel according to claim 1, which is calculated by (D _α + D ₂₄ )/(α + 1) (mm/day), where _α is the displacement amount 24 hours after the start of the measurement in the tunnel A and D ₂₄ . A method for predicting displacement is provided.

The invention according to claim 2 provides a first method of calculating an initial displacement rate that takes into account the amount of displacement of the steel support, based on the displacement measurement of the steel support and the displacement measurement by the underground A measurement. This is an example. Since it is specified that the underground A measurement is to measure the displacement 24 hours after the start of the measurement, the displacement after 24 hours of the underground A measurement is set as _D24 and the displacement D _α of the steel shoring. It is converted into a displacement amount per day (initial displacement speed) using a formula in which the sum of the displacement amounts is the numerator and the measurement time (α+1) (days) is the denominator.

As the present invention according to claim 3, the initial displacement speed is defined as α (hour), which is the time from the start of displacement measurement of the steel shoring to the start of measurement A, and D, the displacement amount of the steel shoring after this α has elapsed. 2. The calculation is performed by (D _α +D _24-α ) (mm/day), where α is the displacement amount after (24 hours-α) has elapsed since the start of the underground A measurement and D _{24-α is} A method for predicting the final displacement of a tunnel is provided.

The invention according to claim 3 provides a second method for calculating an initial displacement rate that takes into account the amount of displacement of the steel support, based on the displacement measurement of the steel support and the displacement measurement by the underground A measurement. This is an example. In this method, the amount of displacement of the steel shoring 24 hours after the start of displacement measurement is determined by (D _α +D _24−α ), and this is taken as the initial displacement rate (mm/day).

The present invention according to claim 4 is a method for predicting the final displacement amount based on the initial displacement speed obtained from displacement measurement in the construction of a mountain tunnel, comprising:
After blasting, the tunnel wall surface is first sprayed, then steel shoring is installed, and the installation position of the steel shoring is measured by measuring the sighting target attached to the steel shoring. A first step of continuously measuring the displacement of the steel shoring after performing the shoring inspection to be performed;
a second step of calculating the initial displacement speed based only on the displacement measurement of the steel shoring, and predicting the final displacement amount from correlation data between the initial displacement speed and the final displacement amount created based on the accumulated data; A method for predicting the final displacement of a tunnel is provided.

In the invention according to claim 4, the displacement of the steel shoring is measured at an earlier stage than the normal underground A measurement, that is, from the stage when the steel shoring is installed, and based only on the displacement measurement of the steel shoring. The initial displacement speed is calculated using The amount of displacement of the tunnel ground after blasting shows a tendency that there is a large initial displacement and then the amount of displacement gradually converges, but for underground A measurement, a collimation target was set on the tunnel wall after the secondary blasting was completed. Measurements could not be started until after this, and measurements were taken after the displacement had begun to converge to a certain extent, so the correlation between the initial displacement speed and the final displacement amount was correspondingly weakened.

Therefore, in the present invention, in order to start displacement measurement as early as possible after blasting, the displacement of the steel shoring is measured after the steel shoring is installed, and the initial stage is based only on the displacement measurement of this steel shoring. Since the displacement speed is calculated, the correlation between the initial displacement speed and the final displacement amount can be improved, and the final displacement amount can be predicted with high accuracy.

As the present invention according to claim 5, the shoring inspection and displacement measurement of the steel shoring are performed by attaching a collimation target to a predetermined location of the steel shoring before erecting the steel shoring. There is provided a method for predicting the final displacement of a tunnel according to any one of claims 1 to 4.

The invention as set forth in claim 5 stipulates a specific method for measuring displacement of steel shoring. In order to efficiently measure the displacement of steel shoring, sighting targets are attached to designated locations on the steel shoring before it is erected, and the shoring can be inspected after the steel shoring is installed. This makes it possible to subsequently measure the displacement of steel shoring.

The present invention according to claim 6 is characterized in that the collimation target attached to the steel shoring is supported by a hinge or a swing arm, and can be retracted by rotation operation so as not to be exposed to blast waves during blasting. There is provided a method for predicting the final displacement of a tunnel according to any one of items 1 to 5.

In the invention set forth in claim 6, there is a concern that the collimation target attached to the steel shoring for measuring the displacement of the steel shoring may be damaged by the blast wave caused by the blasting. Therefore, the collimation target was rotatably supported on a steel support using a hinge or a swinging arm, and the rotation operation enabled the target to be evacuated from the blast wave during blasting, so that it would not be damaged by the blast wave from blasting. It is something.

As described in detail above, according to the present invention, in constructing a mountain tunnel, it is possible to predict the final displacement amount with higher accuracy than before based on the initial displacement speed obtained from displacement measurement.

FIG. 2 is a vertical cross-sectional view of a tunnel showing the procedure for excavating a tunnel. It is a flowchart of tunnel excavation procedure. (A) is a diagram of the procedure for drilling and charging the face with a drill jumbo, (B) is a diagram of the procedure for removing sludge using a wheel loader, and (C) is a diagram of the procedure for primary spraying. FIG. 3 is a front view showing the attachment position of the collimation target 11 to the steel shoring 10. FIG. It is a construction procedure diagram of the steel shoring 10. This is a diagram showing the procedure for shoring inspection. It is a schematic diagram of underground A measurement. It is a drawing of a procedure for driving a rock bolt. It is a graph showing an example of correlation data between an initial displacement speed and a final displacement amount. FIG. 3 is a diagram for explaining an example of calculating an initial displacement speed (mm/day). FIG. 2 is a cross-sectional view showing an example of attaching a collimation target to a steel shoring 10, with (A) showing the time of measurement and (B) showing the time of blasting. It is a measurement procedure diagram of underground A measurement. It is a figure showing the measurement point of underground A measurement.

Embodiments of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1, tunnel construction heavy machinery such as a drill jumbo 1, a spray machine 2, and a wheel loader are arranged near the face S to perform excavation work. The illustrated example is a mini-bench construction method in which excavation is carried out by simultaneous work on the upper and lower halves. In each case, as shown in the flowchart in Fig. 2, a drill jumbo is used to drill holes and charge the face, to break down the upper and lower halves at once (blasting), and then to remove the sludge, remove the hit, and After performing the shoveling, primary spraying is performed on the wall surface using the spraying machine 2, then the steel shoring 10 is erected, and after the secondary spraying is performed, the procedure for driving rock bolts. Excavation is now being carried out by

The present invention provides a method for predicting the final displacement amount based on the initial displacement speed determined from displacement measurement in the construction of the mountain tunnel. Specifically, after performing primary spraying on the tunnel wall surface after blasting, a steel shoring 10 is installed, and a collimation target attached to the steel shoring 10 is measured. A first step of continuously measuring the displacement of the steel shoring 10 after performing a shoring inspection to measure the installation position of the steel shoring 10;
After completing the secondary spraying, the second step is to set up a collimation target on the tunnel wall and start the underground A measurement.
Based on the displacement measurement of the steel shoring 10 and the displacement measurement by the underground A measurement, an initial displacement speed is calculated taking into account the amount of displacement of the steel shoring 10, and is created based on the accumulated data. This step consists of a third step of predicting the final displacement amount from correlation data between the initial displacement velocity and the final displacement amount.

The tunnel excavation process will be explained in detail below.

(Drilling/Charging)
As shown in Fig. 3(A), the drill jumbo 1 is positioned in front of the face S, and the drilling machine 1A mounted on the drill jumbo 1 is used to drill a hole in the face S. Once the charge is placed in the borehole, the upper and lower halves are torn off at once by an explosion (blasting process).

(Drawing out etc.)
Next, as shown in FIG. 3(B), the wheel loader 4 removes the shear. The waste is transported to the outside of the mine by a waste transport vehicle 5. Further, after that, a backhoe or a breaker is used to perform a hit or break (not shown).

(Primary spraying)
Once the work up to this point has been completed, the first concrete spraying work will begin. As shown in Fig. 3(C), the spraying operation is carried out with the spraying machine 2 positioned in front of the face, and the concrete is sprayed approximately 5 cm thick from the spraying nozzle 2a held at the tip of the arm. Spray it on the wall.

(Erection of steel shoring)
Next, construction work for the steel shoring 10 begins. As the steel shoring 10, H-shaped ropes are usually used. Prior to erection work, as shown in FIG. 4, collimation targets 11 are attached to predetermined locations on the steel shoring 10, in the illustrated example five locations: the top, left shoulder, lower left half, right shoulder, and lower right half. Make sure to keep it.

The steel shoring 10 is erected using the spraying machine 2, as shown in FIG. The spraying machine 2 is equipped with two erector devices 2A and 2B for steel shoring, and the steel shoring 10A and 10B, which are divided into two at the center, are held by the erector devices 2A and 2B, respectively. Once the steel supports 10A and 10B have been positioned at predetermined positions along the circumferential direction of the wall surface after excavation, workers on board the baskets 2C and 2D connect the steel supports 10A and 10B at the top position. will be held.

(Shoring inspection)
Next, a shoring inspection is performed to verify whether the steel shoring 10 is installed at the designed position with a predetermined accuracy.

For surveying work, a total station 6 is installed inside the tunnel, as shown in FIG. The total station 6 is a surveying instrument that is equipped with laser irradiation, an automatic sighting function, an automatic sight tracking function, and an automatic leveling correction function in addition to the basic functions of distance measurement and angle measurement. In the measurement, the total station 6 collimates at least two reference points A and B, the coordinates of which are known in advance, and the installation coordinates of the total station 6 are calculated by the backward intersection method applying the principle of triangulation. Since the installation point may change, it is desirable to repeatedly specify the installation coordinates of the total station 6 each time various types of surveying are performed.

As shown in FIG. 6, the inspection of the steel shoring 10 is carried out at at least the left end inspection point, the top end inspection point, and the right end inspection point among the five sighting targets 11 provided on the steel shoring 10. The three collimation targets 11 of the measurement points may be surveyed by the total station 6.

(Displacement measurement of steel shoring 10)
After the above-mentioned shoring inspection is completed, the displacement measurement of the steel shoring 10 is continued. The inspection points are five targets installed on the steel shoring 10. This measurement point was set in accordance with the underground A measurement.

Normally, when the steel shoring 10 is installed along the primary sprayed surface, there are places where spaces are partially formed between the steel shoring 10 and the primary sprayed surface. However, even if a large number of such partial spaces are formed, as long as the steel shoring 10 is in contact with the primary sprayed surface at multiple points in the circumferential direction, it will not disturb the ground. The deformation generally appears as deformation of the steel shoring 10. Therefore, by measuring the displacement of the steel shoring 10, it is possible to understand the deformation of the ground.

In addition, since the displacement measurement of the steel shoring 10 has a strong implication that it is performed as part of the underground A measurement, it is desirable that the measurement frequency be matched with the underground A measurement, which will be described later.

(Secondary spraying)
Once the steel shoring 10 has been erected, a secondary spraying of concrete is performed using a spraying machine 2 to a thickness of approximately 5 to 15 cm.

(Inside mine A measurement)
Once the secondary spraying is completed, underground A measurement will be carried out. When measuring underground A, a collimation target 11 is installed on the secondary spraying surface. As shown in Figure 12, the collimation target 11 is installed at five points: the top, left shoulder, lower left half, right shoulder, and lower right half, and the displacement (and distance between measurement points) and subsidence of each point are measured. Measure the amount.

The survey is carried out by installing a total station 6 inside the tunnel, as shown in FIG. As shown in the figure, it is desirable to use the automatic sighting function of the total station 6 to successively survey a large number of sighting targets.

Regarding the measurement frequency, it may generally be carried out according to Table 1 below.

なお、測定頻度は、内空変位の変位速度より定まる計測頻度と、切羽からの離れによる定まる計測頻度のうち頻度の高い方を採用するものとする。

In addition, the measurement frequency shall be determined by the measurement frequency determined by the displacement speed of the internal space displacement, and the measurement frequency determined by the distance from the face, whichever is higher.

(Rock bolt installation)
After completing the secondary spraying, rock bolts are driven along the radial direction of the tunnel along the circumferential direction of the tunnel, as shown in FIG.

(Prediction of final displacement)
Based on the displacement measurement of the steel shoring 10 and the displacement measurement by the underground A measurement, an initial displacement speed (mm/day) considering the amount of displacement of the steel shoring 10 is calculated, and the data is accumulated. The final displacement amount is predicted from the correlation data between the initial displacement velocity and the final displacement amount created based on. This will be explained in detail below.

First, the method for calculating the initial displacement speed (mm/day) will be specifically explained in detail based on FIG. 9.

<First method>
As shown in the upper part of FIG. 9, the time from the start of displacement measurement of the steel shoring 10 to the start of A measurement is α (days), the displacement amount of the steel shoring 10 after this α has elapsed is D _α , The amount of displacement 24 hours after the start of the measurement in the mine A is defined as _D24 .

The first method is based on the total amount of displacement, which is the sum of the amount of displacement D _α of the steel shoring 10 and the amount of displacement D ₂₄ after 24 hours have elapsed since the start of the measurement of underground A, as shown in the middle part of FIG. The initial displacement velocity is determined by Specifically, since it is stipulated that the amount of displacement after 24 hours has elapsed from the start of measurement in the underground A measurement, the displacement _D24 of the steel shoring after 24 hours has elapsed in the underground A measurement. The displacement amount obtained by adding the displacement amount D _α is the numerator, and the measurement time (α + 1) (days) is used as the denominator to calculate the displacement amount per day (initial displacement speed), which is converted to the initial displacement speed (mm /day). If α: 0.125 days (3 hr), D _α : 20 mm, and D ₂₄ : 60 mm, the initial displacement speed will be (20+60)/1.125=71.1 (mm/day).

Note that the reason for converting the amount of displacement per day is that there is variation in the time α from the start of displacement measurement of the steel shoring 10 to the start of A measurement, and in general, the final displacement is predicted after 24 hours of underground A measurement. This is because since the calculation is based on the amount of time displacement, it is desirable to convert it into the amount of displacement per day based on the relationship with these.

<Second method>
The second method is to directly calculate the amount of displacement of the steel support 10 24 hours after the start of displacement measurement using (D _α + D _24-α ), and use this as the initial displacement rate (mm/day). It is something.

As shown in the upper part of FIG. 9, the time from the start of displacement measurement of the steel shoring 10 to the start of A measurement is α (hour), the displacement amount D _α of the steel shoring 10 when this α has elapsed, and the Assuming that the amount of displacement after (24 hours-α) has elapsed since the start of the measurement of underground A is D _24-α , in the second method, as shown in the lower part of FIG. 9, the amount of displacement D _α of the steel shoring 10 is , the initial displacement speed (mm/day) can be taken as the total displacement amount obtained by adding the displacement amount D _24-α after the start of the measurement in the mine A (24 hours-α). Regarding the displacement amount _D24-α , draw a displacement curve based on the displacement amount _D24 after 24 hours have elapsed from the start of the underground A measurement, and read the displacement amount at the time point (24 hours-α) after the start of the underground A measurement. Alternatively, the amount of displacement D _24-α may be directly measured by measuring the displacement using the total station 6 at a time point (24 hours-α) after the start of the measurement in the mine A.

Once the initial displacement speed (mm/day) has been determined using the above method, the relationship between this initial displacement speed (mm/day) and the final displacement amount (mm) can be plotted for each support pattern, with the horizontal axis representing the initial displacement speed. (mm/day) and plot it on a graph with the vertical axis as the final displacement (mm). When a certain amount of data is accumulated, the shoring pattern (E, DII , DI, CII-b, CI), it becomes possible to obtain correlation data (correlation straight line or correlation curve).

In subsequent excavations, by determining the initial displacement rate (mm/day), it becomes possible to predict the final displacement (mm) based on the correlation data for each shoring pattern. For example, in FIG. 10, if the initial displacement speed is 54 (mm/day) and the shoring pattern is CI, it is possible to predict that the final displacement amount will be 80 (mm).

[Second form example]
In the above embodiment, the displacement of the steel shoring 10 is measured at an earlier stage than normal underground A measurement, that is, from the stage when the steel shoring 10 is installed, and the displacement measurement of the steel shoring 10 and the underground A Although the initial displacement speed was calculated based on the displacement measurement by taking into account the amount of displacement of the steel shoring 10, it is possible to calculate only the displacement measurement of the steel shoring 10, regardless of the above-mentioned underground A measurement. It is also possible to calculate the initial displacement speed based on the , and predict the final displacement amount from correlation data between the initial displacement speed and the final displacement amount created based on the accumulated data.

The displacement behavior of the steel shoring 10 is an indirect displacement of the ground via the steel shoring 10, but the displacement behavior clearly reflects the deformation of the ground. . Therefore, since it is considered that there is a high correlation between the initial displacement rate and the final displacement amount determined from the displacement of the steel shoring 10, it is possible to It becomes possible to predict the final displacement amount based on the initial displacement speed calculated based only on the 10 displacement measurements.

[Other form examples]
(1) Regarding the attachment of the collimation target 11 to the steel shoring 10, the collimation target 11 will remain in place even during subsequent blasting. However, since it is expected that the target will be damaged by the blast during blasting, the collimating target 11 attached to the steel shoring 10 is supported by hinges 13 and can be evacuated by rotation operation so as not to be exposed to the blast during blasting. It is desirable to do so. Specifically, as shown in FIG. 11, the collimation target 11 is fixed to the hinge 13 using a support that connects a fastener 12 and a hinge 13. Attachment to the steel shoring 10 is performed using the fasteners 12, and during measurement the hinge 13 is opened to expose the collimation target 11 to the outside as shown in FIG. ), the hinge 13 is closed to avoid receiving the blast from the face side.

In addition, instead of being supported by the hinge 13, the collimation target 11 is supported by a swinging arm that is swingable around a support shaft, and can be evacuated from being exposed to the blast during blasting by rotating the target. (not shown).

1... Drill jumbo, 2... Spraying machine (with erector device), 3... Material carrier, 4... Wheel loader, 5... Slipper carrier, 6... Total station, 10... Steel shoring, 11... Sighting target, 12... Fastener, 13... Hinge

Claims (6)

A method for predicting the final displacement amount based on the initial displacement speed obtained from displacement measurement in the construction of a mountain tunnel, the method comprising:
After blasting, the tunnel wall surface is first sprayed, then steel shoring is installed, and the installation position of the steel shoring is measured by measuring the sighting target attached to the steel shoring. A first step of continuously measuring the displacement of the steel shoring after performing the shoring inspection to be performed;
After completing the secondary spraying, the second step is to set up a collimation target on the tunnel wall and start the underground A measurement.
Based on the displacement measurement of the steel shoring and the displacement measurement by the underground A measurement, an initial displacement speed that takes into account the amount of displacement of the steel shoring is calculated, and an initial displacement rate is calculated based on the accumulated data. A method for predicting the final displacement of a tunnel, comprising a third step of predicting the final displacement from correlation data between the displacement speed and the final displacement. The initial displacement speed is defined as α (days) from the start of displacement measurement of the steel shoring to the start of A measurement, and D _α the displacement amount of the steel shoring after this α has elapsed, from the start of A measurement in the mine. The method for predicting the final displacement of a tunnel according to claim 1, wherein the calculation is performed by (D _α +D ₂₄ )/(α+1) (mm/day), where the displacement after 24 hours is D ₂₄ . The initial displacement speed is defined as α (time) from the start of displacement measurement of the steel shoring to the start of A measurement, and D _α the displacement amount of the steel shoring after this α elapses, from the start of A measurement in the mine. The method for predicting the final displacement of a tunnel according to claim 1, wherein the prediction method of the final displacement of a tunnel is calculated by (D _α +D _{24-α )} (mm/day), where the displacement after (24 hours-α) is D 24-α. . A method for predicting the final displacement amount based on the initial displacement speed obtained from displacement measurement in the construction of a mountain tunnel, the method comprising:
After blasting, the tunnel wall surface is first sprayed, then steel shoring is installed, and the installation position of the steel shoring is measured by measuring the sighting target attached to the steel shoring. A first step of continuously measuring the displacement of the steel shoring after performing the shoring inspection to be performed;
a second step of calculating the initial displacement speed based only on the displacement measurement of the steel shoring, and predicting the final displacement amount from correlation data between the initial displacement speed and the final displacement amount created based on the accumulated data; A method for predicting the final displacement of a tunnel, the method comprising: According to any one of claims 1 to 4, the shoring inspection and displacement measurement of the steel shoring are performed by attaching a collimation target to a predetermined location of the steel shoring before erecting the steel shoring. A method for predicting the final displacement of the tunnel described. A tunnel according to any one of claims 1 to 5, wherein the collimation target attached to the steel shoring is supported by a hinge or a swing arm, and can be evacuated by rotation operation so as not to receive a blast wave during blasting. How to predict the final displacement.

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