JPH10292788A - Tunnel excavating method by tunnel boring machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable judgement of the strength of rock and property of ground, including cracks accurately by setting the range of excavation energy values corresponding to the kinds of ground property, and obtaining excavation energy to judge the ground property. SOLUTION: The relation between the grade of ground and excavation energy of a tunnel boring machine is obtained by providing a trial excavation section of a planned tunnel line. Raw excavation data are collected, boring data are computed, and then boring energy is computed. In parallel thereto, the grade of ground is determined from face observation, hammer sounding and the property of a boring core. The cumulative distribution of excavation energy is obtained from the result of trial excavation, and the grade of ground is determined. In the procedure from the sampling of raw excavation data to the determination of the grade of ground, if it is taken on every occasion of sampling, determination can be done within real time, the selection of a timbering pattern can be accelerated and the trouble such as the binding of a tunnel boring machine in a soft portion of the ground can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel excavation method using a tunnel boring machine, and more particularly, to a method of judging the nature of ground during tunnel excavation based on the correspondence between excavation energy and ground grade. It relates to a tunnel excavation method using a boring machine.

[0002]

2. Description of the Related Art Recently, in the excavation of a mountain tunnel, a tunnel excavation method using a tunnel boring machine (hereinafter, a tunnel boring machine is also referred to as a TBM, and a tunnel excavation method using the same is also referred to as a TBM method) has been reviewed. Spreading rapidly. The reason for this is that the TBM method has many advantages such as high speed excavation, low noise and low vibration, and less damage to the ground compared to the blasting method. Meanwhile, TB
In the M method, there is also a disadvantage that when the TBM is restrained at the soft ground portion, enormous cost and time are required for the subsequent measures. For this reason, in order to apply the TBM method to a ground whose geology changes rapidly as in Japan, it is important to grasp the geological properties of the ground to be excavated as accurately as possible.

Conventionally, as a preliminary investigation before tunnel excavation, physical exploration such as electric / electromagnetic exploration from the air or the ground and direct investigation by surface exploration or boring have been conducted. Could only understand the geological properties of the site and could not reflect it in actual drilling management. In addition, since the front of the TBM is occupied by the disk cutter, which is also referred to as a full-section tunnel excavator, the face in front of the disk cutter could not be actually observed.

[0004] In view of such a problem, in recent years, researches for investigating a target mountain in detail during tunnel construction by TBM have been actively conducted. The following is an explanation of a prior example (mainly an examination using machine data) regarding a method of investigating the ground during tunnel construction by the TBM.

(1) TSP test The TSP test is based on the propagation of reflected waves measured by generating an artificial earthquake in the ground due to blasting and the like, and the fault crush zone and stratum boundary existing on the tunnel construction base surface in front of the face are considered. It predicts the position and the degree of geological change.

On the other hand, in a study on the relationship between the TBM data and the ground properties, it has been confirmed by a laboratory test using a disk cutter that the thrust thrust and the uniaxial compressive strength of the rock are substantially proportional. Also, thrust thrust,
Individual excavation data such as torque and net excavation speed are compared with the ground conditions. In addition, the relationship between thrust thrust, cutter torque, and net excavation speed has been studied. The following are examples of these studies. (2) "The face stabilization method in TBM excavation" (Kazuhiro Onuma, Hiroyuki Yamamoto, Proceedings of the 24th Symposium on Rock Mechanics, 346-350, 1992)
The relationship between the geological condition of the pit wall and the operation data of the TBM (pure excavation speed, thrust thrust, cutter current value, gripper pressure) in the M construction method has been studied.

(3) "Effects of rock properties and mechanical factors on the workability of TBM" (Koji Ishiyama, Riki Inaba, Koji Nakagawa, Noriyuki Arai, Takashi Hirano, Proc. Of the 24th Symposium on Rock Mechanics, 410-414) P. 1992), T
Correlation between penetration (cm / rev), thrust force, and torque as BM data and the Schmidt hammer rebound, rock grade, and crack density as rock property data is studied.

(4) “Analysis of hard rock excavation results to obtain excavation characteristic formula for TBM” (Kyo Hirano, Koji Ishiyama, Riki Inaba, Koji Nakagawa, Proc. Of the 25th Rock Mechanics Symposium, pp. 306-310) , 1993)
As M data, the correlation between penetration (mm / sec), thrust force, torque and IMS rock mass class is examined.

(5) "Relationship between excavation data of TBM and crack distribution of surrounding rocks" (Takeshi Asano, Seiji Eneko, Tomiharu Iwagaki, Toshiaki Saito, Proceedings of the 28th Rock Mechanics Symposium, 1-7) (1997, p. 1997) discusses the correlation between the estimated uniaxial compressive strength of rock cores collected from bedrock, the excavation energy per unit excavation volume, and the excavation speed per unit propulsion pressure. According to the same paper, the excavation energy per unit excavation volume is calculated as (cutter current value x voltage) / (excavation speed x excavation cross-sectional area). In addition, an excavation speed prediction formula expressing the relationship between the propulsion speed and the propulsion pressure using the uniaxial compressive strength of the rock, the deformation coefficient of the rock, and the crack distribution of the rock has been proposed.

(6) "Consideration on TBM excavation characteristics in hard rock", etc. (Sumio Uematsu, Hisao Ishibuka, Shigeru Takamizawa,
Hagiwara Ikuo, 28th Rock Mechanics Symposium
28-32, 1997), as the TBM data, each of the cutter head total current (A) corresponding to the net digging speed (mm / sec), the total thrust (ton) and the torque,
The correlation with rock mass grade is being studied.

(7) “Estimation of rock mass characteristics using hard rock free section excavator” (Tomoyuki Aoki, Katsunori Fukui, Kuniyasu Ryoke, Yoshihiro Miyamoto, Proc. Of the 28th Rock Mechanics Symposium, 298)
, P. 302, 1997), the excavation energy per unit volume is defined as the total power consumption of the cutter motor minus the power consumption when the cutter wheel is idling, and the measured values of the elastic wave velocity at the face and the Schmidt The correlation with hammer test values is being studied.

(8) "TBM which challenged steep slope of 12%"
New Technology ”(Susumu Yoshino, Kazunori Kozu, Yasuo Iwane, Tsutomu Kiuchi, Tunnel and Underground, pp. 29-34, December 1996), cutter rotation pressure, thrust thrust, net digging speed, cutter The correlation between the cut depth, the main gripper (MG) coefficient, the front gripper (FG) coefficient, and the ground data, such as RQD, Schmitt hammer repulsion value, point loading strength, and underground elastic wave velocity, has been studied.

(9) "Understanding Rock Mass Properties Using TBM Excavation Resistance" (Katsunori Fukui, Seisuke Okubo, Tunnel Underground, pp. 35-43, February 1996)
A method for estimating rock strength based on the correlation between thrust during excavation and rock strength, and the correlation between torque and depth of cut and rock strength has been studied.

(10) "Technology for predicting rock formation and geology in front of face using drilling data by hydraulic drilling" (Kenji Aoki, Takeshi Inaba, Yukihiro Shiogama, Yasunari Tezuka, No. 8)
Proceedings of the National Symposium on Mechanics of Kaiiwa, 67-72
Page, 1990), in a so-called advanced boring survey, when drilling with a hydraulic percussion drill, the drilling speed, drilling cross-sectional area,
A method is disclosed in which the fracture energy for the rock is obtained from the piston impact energy and the number of piston strikes, and the correlation between the fracture energy and the rock grade is used to predict the rock grade of the ground to be drilled.

[0015]

However, these prior arts have various problems. That is, in the TSP test (1), since the relationship between the rock mass and the elastic wave velocity is complicated, it was difficult to accurately determine the nature of the ground based on this.

In the preceding examples of the above (2) to (4), (6), (8) and (9), the relation between the individual excavation data and the ground data is poor in theoretical grounds, Although the correlation or multiple correlation analysis is performed, the correlation is poor, so that the nature of the ground cannot be determined with high accuracy based on the correlation. In addition, in some correlation analysis examples, there are some correlations between excavation data and ground properties, but the coefficients obtained from these analyzes need to be calibrated each time the rock type changes. There is no practical. Further, in order to determine the nature of the ground by these methods, data other than the excavation data to be compared with the nature of the ground must be constant, so that it has been difficult to apply the method to construction work.

In the preceding example of (8), the results of Schmitt hammer, RQD, point load test, simple elastic wave test, and the like are used as the ground data, but these can be used as a guide and the entire face However, since it does not accurately represent the information of the excavation, there is a problem that it is not possible to accurately grasp the relationship between the nature of the ground and the excavation data.

On the other hand, as in the preceding examples (5) and (7), the electric energy is directly used as the excavation energy,
The direct use of the current value as the cutter torque as in the preceding example of (6) is based on the fact that these values change depending on the output characteristics of the machine. Is not preferred. The preceding examples of (7) and (10) are directed to hydraulic drills and free-section excavators, but these devices have a small excavated portion, and can obtain excavation data and ground data for the entire face. It cannot be used for TBM as it is.

Therefore, a main object of the present invention is to propose a tunnel excavation method which solves all the above problems and enables more accurate determination of the nature of the ground.

[0020]

According to the present invention, there is provided a tunnel excavation method using a tunnel boring machine, wherein excavation energy is obtained at the time of excavation of a tunnel, and ground properties are determined based on the excavation energy. It is.

In the present invention, since the excavation energy is used in determining the ground level, it is necessary to keep the values of the thrust thrust, the cutter torque, the net excavation speed and the like constant as in the above-mentioned prior example. Not really. Therefore, TBM
Excavation management (including excavation data management) is easy, and the judgment rate of the nature of the ground is high. When the excavation energy is used as a criterion, it is possible to determine not only the strength of the rock at the ground, but also the nature of the ground including cracks and the like existing at the face. Furthermore, since the determination target of the present invention has the nature of the mountain, there is no need to perform calibration due to the difference in rock type.

In the present invention, the excavating energy is:
It can be obtained based on the thrust thrust, the thrust speed, the stroke length of the thrust jack, the cutter torque, and the cutter rotation speed. In this case, it is preferable that the cutter torque value is obtained from an output characteristic curve of the cutter torque. By using the torque actually generated by the TBM, the cutter torque value can be obtained with higher accuracy, and the determination accuracy of the ground property can be improved.

In the present invention, prior to the tunnel excavation, a range of excavation energy values corresponding to various types of ground properties is determined, and the ground properties are determined based on the range of the excavation energy values. be able to.

Further, in the present invention, it is possible to select a support pattern using the result of the determination of the nature of the ground.

Furthermore, in the present invention, it is preferable that after the tunnel excavation is performed for a predetermined distance, the range of the excavation energy value corresponding to each type of the mountainous nature is determined again.

In the present invention, the ground properties are preferably ground grade. Further, it is more preferable that the ground property is at least one of an evaluation point of the ground and an overall evaluation point of the ground.

[0027]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 2 schematically shows the TBM. The TBM body 1 is provided with a cutter head 3 in front of it through a thrust jack 2, which is fixed to the ground 4 by a main gripper (not shown) at the time of excavation, and the cutter head 3 is grounded by the thrust jack 2. The ground 4 is excavated by being rotated while being pressed against the ground 4. In the present invention, a known TBM, for example, both an open type TBM and a full shield type TBM can be used. There are hydraulic and electric rotary means for rotating the cutter head, and both can be used in the present invention.

In the present invention, when excavating by TBM,
First, at least a thrust thrust F, a thrust speed, a stroke length, a cutter torque T, and a cutter rotation speed are obtained.

The thrust thrust F can be obtained by multiplying the thrust pressure measured by a hydraulic pressure gauge (not shown) of the thrust jack 2 by the internal cross-sectional area of the jack and the number of jacks used. The thrust speed is obtained by dividing one stroke length L of the thrust jack by the time required for one stroke.

When the rotary drive source of the cutter head 3 is hydraulic, the cutter torque T can be directly obtained based on the cutter pressure measured by a hydraulic gauge (not shown) of the cutter hydraulic pump. On the other hand, when the rotary drive source is an electric motor, it is possible to theoretically calculate the cutter torque from the input current and the input voltage as in the conventional example described above, but the cutter torque obtained by this and the actually generated cutter torque can be calculated. There is an error between the cutter torque and the cutter torque.
Therefore, for example, it is preferable to actually measure the relationship between the input current value and the cutter torque to obtain an output characteristic curve as shown in FIG. 3, and to obtain the cutter torque value from the current value measured during excavation based on this. Of course, input power can also be used. Since the output characteristic curve reflects the characteristics specific to the device of the TBM, a more accurate cutter torque value can be obtained.

One stroke length L of the thrust jack
Is a substantially constant value determined by the performance of the thrust jack itself. The rotation speed of the cutter is
It is determined by multiplying the rotation capacity per unit (rpm) by the number of cutter rotary pumps used, and this is also determined at a substantially constant value depending on the performance of the apparatus itself.

In the present invention, excavation energy is obtained from the thrust thrust, the thrust speed, the stroke length, the cutter torque, and the cutter rotation speed. As a method of obtaining the excavation energy, a method using the following equations (1) and (2) is proposed. E = {(F−F0) × L + 2π × (T−T0) × N} / V (1) N = n × L / v (2) where E: per unit excavation volume Drilling energy (tf /
m ²⁾ F: Thrust thrust (tf) F0: frictional force caused by the mechanical structure of the thrust jacks (tf) L: length of one stroke of the thrust jacks (m) T: Cutter torque (tfm) T0: the cutter head Torque value (tfm) corresponding to frictional force due to mechanical structure N: Number of cutter rotations per rotation of thrust jack (rotation) n: Number of cutter rotations (rpm) v: Thrust speed (m / min) V: Excavation volume per stroke of thrust jack (m ³ ) Above, how to obtain thrust thrust, cutter torque, thrust speed and excavation energy in TBM excavation has been described. Therefore, the tunnel excavation method of the present invention including determination of the nature of the ground based on excavation energy will be described in detail below based on experimental examples.

In this example, examples of ground grades shown in Tables 1 and 2 (the symbols .largecircle., .Quadrature., .Quadrature. And .circle-solid. In Table 1 correspond to those in Table 2) are used. Of course, other ground grades can be used. In the table, C _{H to} C _L are all C in this example.

[0034]

[Table 1]

[0035]

[Table 2]

The tunnel excavation of this embodiment will be described with reference to the flow chart shown in FIG. 1. First, the correspondence between the ground grade and the excavation energy of the TBM in a planned tunnel line predetermined for the ground is grasped. A test excavation section was set up for the drilling. This test excavation section is desirably a section sufficient for sampling data necessary for determination of a determination value to be described later in a mountainous portion of a grade where excavation is performed for the first time. In order to set this test excavation section, it is also possible to perform preliminary survey drilling for the target ground and grasp the change in the ground grade along the planned tunnel line in the ground.

In excavation in the test excavation section, TBM
The drilling raw data (oil pressure of thrust jack, supply current value to cutter torque, thrust pressure, stroke length of thrust jack, etc.) are sampled at appropriate intervals, and the drilling data (thrust thrust, thrust thrust, Thrust speed, stroke length, cutter torque, cutter rotation speed) were calculated, and the excavation energy E per unit excavation volume was calculated by the above equations (1) to (3).

On the other hand, in FIG. 1, in parallel with the calculation of the excavation energy E, the ground grade is determined based on the face observation and the hammer percussion of the ground sampling part. This may not be possible depending on the type or the like. In this example, the TBM used was a full shield type, and the method used was to use segments for lining and to assemble the segments immediately after the excavation was completed, so that face observation in test excavation could not be performed. Therefore, in this example, instead of determining the ground grade based on the face observation and the like, the ground grade is determined from the properties of the boring core obtained by performing the preceding horizontal boring.

In the case where the ground grade is determined based on the face observation and the hammer strike, the ground grade is determined based on, for example, the criteria shown in Tables 3 and 4 for the ground grade based on the face observation and the hammer strike. You only need to judge the grade. That is, an evaluation point is given to each classification element based on the face observation result and the hammer percussion result based on Table 4, and the ground grade is determined from Table 3 based on the total evaluation point.
In addition, when face observation or the like is possible, for example, there is a case where an open type TBM is used, or a case where a face observation or the like is possible behind a machine even with a full shield type.

In the present invention, in the test excavation, instead of the judgment of the ground grade based on face observation and hammering, another judgment method of the ground grade can be used.

[0041]

[Table 3]

[0042]

[Table 4]

From the results of the test excavation, for example, as shown in FIG. 4, the cumulative distributions b to d of the excavation energy E corresponding to the respective ground grades B to C were obtained. Curves b ′ to d ′ are normal distribution curves of the cumulative distributions b to d. In this example, since the number of samples of the excavation data relating to the ground grade A was not sufficient, this was excluded from the determination target. However, in the practice of the present invention, when the ground grade A is other ground grades, Can be determined in the same manner as

Since these normal distribution curves b 'to d' overlap each other in the direction of the horizontal axis (digging energy E), the range of the drilling energy value corresponding to each mountain class is determined by the following method. That is, as shown in FIG. 7, between two adjacent distributions, one cumulative distribution is a cumulative distribution from the left and the other cumulative distribution is a cumulative distribution from the right to obtain cumulative distributions in opposite directions. In this method, an X-axis value determined as an intersection of the cumulative distributions is used as a discrimination value between two adjacent distributions. The discrimination rate is Y at the intersection as shown in FIG.
The axis value can be obtained by subtracting 1 from the axis value.
f ₁ and f ₂ are respective probability density functions.

FIG. 5 shows a case where this method is applied to this embodiment. Now, focusing on d ′ and c ′ as adjacent normal distribution curves, a normal distribution curve d ″ is created from the right with respect to the normal distribution curve of d ′, and the intersection of this and the distribution curve c ′ is
It is a discrimination value between the ground grades D and C, and is approximately 2440.0 (t
f / m ² ). Similarly, ground grade B and ground grade C
As a result of determining the discrimination value of about 3090.0 (tf /
m ² ). Table 5 shows the results of determining the discrimination rate together with these discrimination values.

[0046]

[Table 5]

Accordingly, the range of the excavation energy value E corresponding to each mountain class is a range determined by these discrimination values, and in this case, is as shown in Table 6.

[0048]

[Table 6]

After the excavation energy determination value is determined,
Start the main excavation. Also in this excavation, sampling of excavation raw data is performed, and excavation data (thrust thrust, thrust speed, stroke length, cutter torque, cutter rotation speed) are calculated from these raw data, and excavation energy is calculated based thereon. Was. The digging energy obtained in the current digging part is calculated as
In comparison with the range of the excavation energy value corresponding to D (see Table 2), the ground grade in the current excavation portion was determined.

FIG. 6 shows the distance from the tunnel entrance,
(A) Excavation energy value obtained from excavation data, (b)
Ground grade determined by face observation and hammering,
And (c) is a graph showing the relationship between the excavation energy and the determination result of the ground grade.

As is clear from the figure, the judgment result of the ground grade based on the excavation energy showed good agreement with the ground grade determined based on face observation and hammering.

The procedure from the sampling of the raw excavation data to the determination of the ground grade is sequentially performed for each sampling of the raw excavation data, and the determination of the ground grade in the current excavation portion is quickly performed in real time. This makes it possible to speed up the selection of the support pattern thereafter and to avoid troubles such as restraint at the soft ground portion of the TBM.

<Other Embodiments> In the present invention, it is possible to select a support pattern by using the determination result of the ground grade. That is, based on the support pattern corresponding to each mountain grade as shown in Table 7, the support pattern is selected from the ground grade determined from the excavation energy as described above. Table 7 is referred to as a standard design pattern, and other patterns can be applied. The selection of the support pattern can be automated.

[0054]

[Table 7]

If the procedure from the sampling of raw excavation data to the selection of the support pattern is also performed sequentially for each sampling of the raw excavation data, the support pattern in the current excavation portion can be quickly selected in real time. Can be.

Further, the value of the excavation energy E obtained in the main excavation gradually increases as a whole due to the wear of the cutter head and the increase in the binding force of the ground against the TBM which increases as the excavation depth increases. Is assumed. Therefore, as shown in FIG.
It is desirable to provide a new test excavation section and reset the excavation energy discrimination value. Therefore, the predetermined distance referred to in the present invention is a distance at which the increase in the excavation energy E obtained in the main excavation due to the influence of the wear of the cutter head and the increase in the binding force of the ground against the TBM is not significant ( (About 1000 m in a normal TBM).

Further, in the above example, the ground judgment is performed by using the correspondence between the excavation energy and the ground grade. However, the correspondence between the excavation energy and the evaluation score of the ground or the comprehensive evaluation point is used. Is more preferred. That is, in the test excavation, the correspondence between the excavation energy and the ground evaluation point or the comprehensive evaluation point is grasped, and the ground evaluation point or the overall evaluation point is determined from the excavation energy obtained in the main excavation. The evaluation score of the ground or the total evaluation score is determined by numerical values unlike the grade evaluation such as the ground grade, so that it is possible to grasp the correspondence with the excavation energy by performing regression analysis, etc. There are advantages. Since the evaluation points and the total evaluation points have been described above, they will be omitted here.

[0058]

As described above, according to the present invention, mainly the following effects can be obtained. (1) Since the nature of the ground can be determined without depending on the type of rock, there is versatility. (2) Excavation data such as thrust thrust, cutter torque, and pure excavation speed do not need to be constant, so excavation management is easy and determination accuracy is improved. (3) Since the nature of the ground can be determined without performing face observation, the nature of the ground in front of the cutter disc can be determined even with a full shield type TBM. (4) Since the nature of the ground in the current excavated portion can be quickly determined, it is possible to promptly select a support pattern and cope with a trouble thereafter. (5) Since no human judgment is required for selecting the support pattern, the excavation by the TBM can be fully automated. (6) When the correspondence between the excavation energy and the evaluation score of the ground or the comprehensive evaluation point is used, since the evaluation point is a quantitative value, the correspondence between the excavation energy and the excavation energy is subjected to regression analysis or the like. It becomes possible to grasp.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of tunnel excavation according to the present invention.

FIG. 2 is a schematic view of a tunnel boring machine.

FIG. 3 is a graph showing a relationship between a cutter supply current value and a cutter torque.

FIG. 4 is a graph of a cumulative distribution of excavation energy.

FIG. 5 is a graph of a cumulative distribution of excavation energy.

FIG. 6 shows the relationship between the distance from the tunnel entrance and (a) the excavation energy value obtained from the excavation data, (b) the relationship with the ground grade obtained by boring core analysis, and (c) the ground grade in the main excavation. 6 is a graph showing the relationship with the determination result.

FIG. 7 is a diagram illustrating a principle of calculating a discrimination value.

[Explanation of symbols]

1 ... Tunnel boring machine body, 2 ... Thrust jack, 3 ... Cutter head, 4 ... Ground mountain.

Continuation of the front page (72) Inventor Shoichi Ando 4-12-20 Nihonbashi Honcho, Chuo-ku, Tokyo Inside Sato Industry Co., Ltd.

Claims (8)

[Claims] 1. A tunnel excavation method using a tunnel boring machine, wherein excavation energy is obtained at the time of excavation of a tunnel, and ground properties are determined based on the excavation energy. 2. The tunnel excavation method according to claim 1, wherein the excavation energy is obtained based on a thrust thrust, a thrust speed, a stroke length of a thrust jack, a cutter torque, and a cutter rotation speed. 3. The tunnel excavation method using a tunnel boring machine according to claim 2, wherein the cutter torque value is obtained from an output characteristic curve of the cutter torque. 4. Prior to the tunnel excavation, a range of excavation energy values corresponding to various types of ground properties is determined, and the determination of the ground properties is performed based on the range of the excavation energy values. A tunnel excavation method using a tunnel boring machine according to any one of claims 1 to 3. 5. The tunnel excavation method using a tunnel boring machine according to claim 1, wherein a support pattern is selected using the result of the determination of the nature of the ground. 6. After performing the tunnel excavation for a predetermined distance,
The tunnel excavation method using the tunnel boring machine according to any one of claims 1 to 5, wherein the range of the excavation energy value corresponding to each of the types of the ground properties is determined again. 7. The ground property is a ground grade.
7. A tunnel excavation method using a tunnel boring machine according to any one of items 6 to 6. 8. The tunnel excavation method using a tunnel boring machine according to claim 1, wherein the ground property is at least one of an evaluation score of the ground and an overall evaluation score of the ground.