JP2003003789A - Evaluation method of property of tunnel excavated natural ground - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation method of the property of a tunnel excavated natural ground capable of efficiently executing a supporting of a tunnel corresponding to the property by safely and accurately deciding the property of an excavated natural ground when the natural ground is excavated as a tunnel by a partial tunnel face excavation machine. SOLUTION: When the tunnel is excavated while pushing a cutter drum put on the front end of a boom of the partial tunnel face excavation machine against the bedrock thereby, and since there is mutual relation between vibration force (maximum amplitude value) of the boom generated in the case of excavation and an evaluation point of the bedrock to be artificially measured, the vibration force of the boom is measured to calculate an evaluation point of the bedrock from the vibration data, and the property of the tunnel excavated bedrock is evaluated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of evaluating the properties of a tunnel excavated ground, which enables safe and efficient judgment of the properties of the excavated ground when constructing a tunnel.

[0002]

2. Description of the Related Art When a rock mass is excavated by a free-section excavator when constructing a tunnel, the tunnel is supported to prevent skin fall and collapse of the excavated tunnel wall and to ensure the safety of workers. ing. The support for this tunnel will be set according to the evaluation score of the bedrock. The evaluation point of this bedrock is based on the observation items such as the impact of the hammer and the weathering alteration degree by hammers, the interval of cracks, the condition, the direction, the presence of spring water, etc. It is decided by observing the properties artificially. The evaluation score of this bedrock is
Each of the above evaluation items is scored, and these are combined to make a comprehensive evaluation point. This evaluation point represents the stability of the natural ground.

The support of the tunnel includes the injection of shotcrete, the support of the ring, the installation of the rock bolt, etc., and the optimum support means is determined based on the evaluation point of the rock mass determined by the above-mentioned artificial observation. You have selected. The most important evaluation item of the rock mass is the compressive strength of the rock mass. This judgment of the compressive strength is usually made by hitting the natural ground with a hammer or observing it as described above.

[0004]

However, in such a judgment method, it is necessary to rely on the experience and intuition of a skilled measurer, and an inexperienced measurer cannot make an accurate judgment. Individual differences will occur depending on the measurer. Further, since the work is performed on the exposed wall surface of the excavation inside the tunnel, there is a risk that the rock mass may collapse and there is a risk.

The ground evaluation methods other than the observation by the measurer include the excavation position of the free section excavator, the load of the excavation motor,
There is a method to analyze the excavation data such as the pressing force of the cutter drum against the natural ground to evaluate the natural ground. Among these excavation data, the data showing the nature of the ground is considered to be the load of the cutting motor and the pressing force of the cutter drum, but in the past data analysis, there is a difference between the nature of the ground and these data. The current situation is that no clear correlation is recognized. In addition, as a method for accurately obtaining the compressive strength, there is a method in which a specimen is taken from the ground and a strength test is performed on the specimen, but this method requires a significant amount of time and effort to determine the properties of the ground. In short, there is a problem that the tunnel construction work process is delayed.

The present invention has been made in view of the above problems, and an object thereof is to make it possible to safely, easily and accurately evaluate the characteristics of the ground when constructing the tunnel. It is to provide a method for evaluating the properties of excavated ground.

[0007]

In order to achieve the above object, the method for evaluating the properties of a tunnel excavation ground according to the present invention is characterized in that the excavation means provided at the tip of the boom is mounted on the bedrock as described in claim 1. When the rock is excavated by pressing, the vibration value of the boom at the time of excavation is measured, and the rock evaluation point is calculated from the vibration data. The vibration value of the boom is, specifically, the maximum amplitude value of the boom as described in claim 2.

In the method for evaluating the property of the ground for excavating the tunnel, the vibration value of the boom changes depending on the magnitude of the pressing force of the means for excavating the tip of the boom against the rock. Therefore, claim 3
The invention according to (1) is characterized in that the maximum amplitude value is corrected according to the pressing force of the boom excavating means. That is, the reference value of the maximum amplitude value of the boom corresponding to the reference value of the pushing force of the boom tip excavating means against the rock is obtained in advance, and the actual measurement value of the pushing force of the boom tip excavating means during rock excavation is obtained. The maximum amplitude value of the boom is corrected by obtaining a converted value of the maximum amplitude value from and adding the difference between the converted value and the reference value of the maximum amplitude value to the measured value of the maximum amplitude value.

Further, according to a fourth aspect of the present invention, for each fixed range of the pressing force of the boom tip excavating means against the rock mass, the maximum amplitude value of the boom corresponding to the pressing force within each range and the rock mass evaluation point are provided. A conversion formula is set in advance, and the rock mass evaluation point is calculated by a conversion formula corresponding to the pressing force of the boom tip excavation means during excavation.

Further, according to a fifth aspect of the present invention, the rock mass is calculated from the maximum amplitude value of the boom corresponding to the pressing force within each range of the pressing force of the boom tip excavating means against the bedrock and the pressing force for each fixed range. It is characterized in that a relational expression for obtaining the evaluation point of is set, and the evaluation point of the bedrock is calculated by the relational expression corresponding to the pressing force of the tip excavating means of the boom at the time of excavation. The most important evaluation point of rock mass is the evaluation point of compressive strength as described in claim 6.

[0011]

[Advantageous effects] When the excavation means attached to the tip of the boom of the free-section excavator is pressed against the rock to be excavated and the rock is excavated, the boom itself vibrates. Since this vibration value fluctuates in proportion to the hardness of the bedrock, the maximum amplitude value of vibration is measured by an accelerometer attached to the boom, and the nature of the ground is evaluated from this vibration data. That is, since there is a correlation between the maximum amplitude value of the vibration of the boom when excavating a certain part and the evaluation point of the bedrock where the operator artificially observed and evaluated that part, the boom vibration Create a conversion formula that can calculate the rock mass evaluation point from the maximum amplitude value,
During excavation by an excavator, the maximum amplitude value of the boom is measured, the rock mass evaluation point corresponding to the maximum amplitude value is obtained from the above conversion formula, and the supporting means corresponding to the evaluation point is selected.

As described above, since a skilled measurer or the like preliminarily evaluates an accurate rock mass evaluation point artificially obtained by the vibration data of the boom of the free cross-section excavator, the measurer or the like It is possible to safely and accurately evaluate the properties of the ground without needing to approach the exposed excavation ground, and to efficiently and efficiently excavate the tunnel and to easily and accurately set up the support of the tunnel corresponding to the properties of the excavation ground. can do.

Further, the vibration data of the boom measured at the time of excavation is converted into the rock mass evaluation point of the excavated portion by the conversion formula of the maximum amplitude value of the boom and the rock mass evaluation point which are obtained in advance. The properties of the ground can be quantitatively and objectively evaluated, and the properties of the ground can be evaluated continuously for each excavation section. It is possible to efficiently construct the support of the tunnel according to the evaluation value.

Since the maximum amplitude value of the boom changes depending on the magnitude of the pressing force of the boom tip excavating means against the natural ground, the maximum amplitude value is corrected according to the change of the pressing force to obtain accurate rock mass. It is necessary to ask for the evaluation score of. As the correction method, as described in claim 3, first, a reference value of the maximum amplitude value of the boom corresponding to the reference value of the pressing force of the boom excavating means against the rock is calculated. Then, the converted value of the maximum amplitude value is obtained from the measured value of the pressing force of the excavating means during rock excavation, and the difference between this converted value and the reference value of the maximum amplitude value is added to the measured value of the maximum amplitude value to detect the boom. This method corrects the maximum amplitude value.According to this method, even if the nature of the ground changes during excavation of the ground by an excavator, the rock mass evaluation points can be accurately detected and evaluated according to the characteristics. can do.

Similarly, as described in claim 4, for each predetermined range of the pressing force of the tip excavating means of the boom against the rock mass, the maximum amplitude value of the boom and the rock mass corresponding to the pressing force within each range are previously set. Set the conversion formula with the evaluation point,
It is also possible to calculate the rock mass evaluation point from the above conversion formula corresponding to the pressing force of the excavating means during excavation by the excavator,
As described in claim 5, for each constant range of the pressing force of the excavating means against the rock mass, the rock mass evaluation point is calculated from the maximum amplitude value of the boom corresponding to the pressing force within each range and the pressing force. Set the relational expression to be obtained, and from the relational expression corresponding to the pressing force of the excavating means during excavation by the excavator, use the pressing force of the boom tip excavating means during excavation by the excavator and the maximum amplitude value as the rock mass evaluation point. The properties of the rock mass of the excavated portion can be accurately detected and evaluated by conversion and calculation, and the tunnel can be supported in accordance with the property of the excavated portion.

[0016] The most important evaluation item of rock mass is the evaluation point of compressive strength, and the maximum amplitude value of the boom when excavating a certain part and the part are measured by the measurer. Since a considerably high correlation is recognized with the compression strength evaluation point that has been observed and evaluated, the compression strength evaluation point is obtained from the maximum amplitude value of the boom by the same method as described above. be able to.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Next, as a concrete embodiment of the present invention, a method for obtaining a compression strength evaluation point of the ground from the maximum amplitude value of a boom will be described with reference to the drawings. As shown, the excavator 1 is a free-section excavator, and the free-section excavator 1 has a boom 3 that swivels in the vertical and horizontal directions by operating a plurality of hydraulic jacks at the front end of a moving carriage 2 including a crawler carriage. And a cutter drum 4 as excavating means is attached to the tip of the boom 3 so as to be movable back and forth.
An acceleration converter 5 is attached to the vehicle, and the acceleration converter 5 is configured to measure the vibration of the boom 3 generated during excavation by the cutter drum 4.

Further, the boom 3 is equipped with a telescope type detector 6 for detecting the pressing force of the cutter drum 4 against the natural ground (rock mass), while the hydraulic jack 7 for rotating the boom 3 in the vertical direction. Is provided with a vertical pressure detection port 8 thereof, a hydraulic jack 9 for turning in the horizontal direction is provided with a horizontal turning pressure detection port 10, and a vertical angle detector 11 is mounted at the turning center of the boom 3. In addition, a detector (not shown) for detecting the voltage and current of the drive motor for the cutter drum 4 is provided at an appropriate position of the free section excavator 1.

When a tunnel is excavated by the free cross-section excavator 1 constructed in this way, the vibration (maximum amplitude value) of the boom 3 detected by the acceleration transducer 5 and the observer artificially observe it with a hammer or the like. As shown in FIG. 2, a high correlation was observed between the evaluated compression strength evaluation points (graded evaluation). That is, in FIG. 2, the horizontal axis indicates the tunnel excavation distance from the wellhead, and the vertical axis indicates the compressive strength evaluation point and the maximum amplitude value of the boom 3, and each time a tunnel of a certain length is excavated, the face ground is excavated. It is a graph showing the results of obtaining the compression strength evaluation point and the maximum amplitude value, and the compression strength evaluation point and the maximum amplitude value of the boom 3 have a proportional relationship.

Since the compression strength evaluation point and the maximum amplitude value of the boom 3 have such a correlation, the compression strength evaluation point corresponding to the maximum amplitude value of the boom 3 is previously determined. A conversion formula to be obtained is created by regression analysis, and when excavating a tunnel by the free cross-section excavator 1, a boom that occurs when excavating the cutter drum 4 against the ground (rock) with a constant pressing force. Three
The maximum amplitude value of the cutter drum 4 is measured by the acceleration converter 5, and the compression strength evaluation point is converted from the measured value in real time by the above conversion formula.
The property of the ground of the excavated portion is evaluated, and the support means corresponding to the evaluation value is selected to support the tunnel in the excavated portion. This conversion formula is shown in Formula 1.

[Formula 1] y = a × x + b ... In the above conversion formula, y is a compression strength evaluation point, x is a maximum amplitude value, and a and b are coefficients.

Further, by displaying the relationship between the maximum amplitude value of the boom 3 and the compression strength evaluation point as a diagram as shown in FIG. 3 from the above conversion formula, the excavation of the maximum amplitude value of the boom 3 is performed. It is possible to directly judge the compressive strength evaluation point of the portion.

When the tunnel is excavated by the free section excavator 1 as described above, the acceleration converter 5, the telescope type detector 6, the vertical pressure detection port 8, which are arranged in the free section excavator 1, Left / right turning pressure detection port 1
0, voltage for detecting the load of the drive motor of the cutter drum 4, the excavation position and the load of the drive motor detected by the current detector, the pressing force of the cutter drum 4 against the ground, the boom 3
As shown in FIG. 4, the excavation data such as the vibration data of No. 1 is A / D converted by the signal conversion boom 3, and then the free section excavator 1
It wirelessly transmits from the transmission unit equipped with to the receiving unit of the receiving device arranged in a proper place such as in a tunnel, and the arithmetic processing unit of this receiving device performs arithmetic processing for each of the above measurement items to evaluate the characteristics of the natural ground. The display printing unit prints the evaluation result.

Next, in the above embodiment, the boom 3
The shape of the rock mass is calculated by calculating the compression strength evaluation point of the rock mass from the maximum amplitude value of the boom 3 when excavating while the cutter drum 4 attached to the tip of the rock is pressed against the rock mass with a constant pressing force. However, when the pressing force of the cutter drum 4 changes to a large or small value, the maximum amplitude value of the boom 3 fluctuates accordingly, resulting in a difference in the relationship with the compression strength evaluation point. For example, the pressing force of the cutter drum 4 tends to be large when the ground is hard and small when the ground is soft.
The pressing force of the cutter drum 4 is also affected by the excavation procedure and habits of the operator. Further, even if the rock itself is hard, if numerous cracks are formed in the bedrock, excavation can be performed without increasing the pressing force of the cutter drum 4.

FIG. 5 shows a case where the correlation between the maximum amplitude value of the boom 3 and the compression strength evaluation point changes as described above, and the horizontal axis shows the wellhead excavated by the free-section excavator 1. And the vertical axis shows the compression strength evaluation point and the maximum amplitude value of the boom 3. In this figure,
The maximum amplitude value of the boom 3 and the compression strength evaluation point correspond relatively well on the pit side from 305 m, but in the tunnel on the front side of 305 m, the boom 3 corresponds to the compression strength evaluation point.
The maximum amplitude value of is relatively small. This is 30
The pressing force of the cutter drum 4 changes in correspondence with the change of the compressive strength evaluation point on the pit side from 5 m, but on the front side of 305 m due to the change in rock quality as described above. The pressing force is insufficient and the maximum amplitude value is relatively small.

As a countermeasure against this, a method of correcting the maximum amplitude value of the boom 3 according to the magnitude of the pressing force of the cutter drum 4 is used. In this method, since the pressing force and the maximum amplitude value have a correlation with each other, the relational expression between them is set as shown in the following mathematical formula 2. In this relational expression, the pressing force that becomes the reference of the cutter drum 4 against the natural ground (rock mass) is determined, and the reference value of the maximum amplitude value of the boom 3 corresponding to the reference value of this pressing force is shown in the following mathematical expression 3. I will get it from the formula. Then, from the measured value of the pressing force of the cutter drum 4, the converted value of the maximum amplitude value of the boom 3 is obtained from the relational expression shown in the following formula 4, and based on the relational formula shown in the formula 5, from the relational expression shown in the above formula 2. The difference is corrected by adding the difference between the reference value of the obtained maximum amplitude value and the converted value obtained from the relational expression shown in Expression 3 to the actual measurement value. Figure 6
FIG. 4 is a diagram showing a method of correcting the maximum amplitude value based on Expressions 1 and 2.

[Formula 2] H = f (T) ...

[Formula 3] H0 = f (T0) ...

[Formula 4] Hb = f (Ta) ...

[Equation 5] Hh = Ha + (H0-Hb) ...

In the equations 2 to 5 and FIG. 6, H: maximum amplitude value, H0: reference value of maximum amplitude value, Ha: actual measured value of maximum amplitude value, Hb: conversion of maximum amplitude value. Value, Hh: correction value of maximum amplitude value, T: pressing force, T
0: Reference value of pressing force, Ta: Actual value of pressing force.

According to this correction method, the value shown in FIG.
As a result of correcting the maximum amplitude value on the front side of 5 m, the result is as shown in FIG. 7, and the maximum amplitude value of the boom 3 and the compression strength evaluation point correspond relatively well.

In the above embodiment, the cutter drum 4
The maximum amplitude value of the boom 3 is corrected according to the pressing force of the boom 3, but as another measure, the maximum amplitude value of the boom 3 and the compression strength evaluation point are changed for each pressing force of the cutter drum 4. A method of dividing the conversion formula can be used. That is, for each constant range of the pressing force of the cutter drum 4 against rock, a conversion formula between the maximum amplitude value of the boom 3 and the compression strength evaluation point corresponding to the pressing force within each range is set, and the cutter during excavation is set. A method of calculating the compression strength evaluation point by a conversion formula corresponding to the pressing force of the drum 4 is adopted.

In this case, the relationship between the maximum amplitude value of the boom 3 and the compression strength evaluation point is the same as the conversion formula shown in the above mathematical expression 1, and the compression strength evaluation point is obtained by this conversion formula. For example, the pressing force of the cutter drum 4 is 4.0 to 6.0 MPa,
Divide into ranges such as 6.0 to 8.0MPa and 8.0 to 10.0MPa, analyze the relationship between the maximum amplitude value of the boom 3 and the compression strength evaluation point in each range, set the conversion formula as described above, and set the free cross section. The maximum amplitude value is converted into a compression strength evaluation point using a conversion formula corresponding to the pressing force of the cutter drum 4 when the excavator 1 excavates a tunnel. FIG. 8 shows the procedure for obtaining the compression strength evaluation points by this method.

As another embodiment, for each constant range of the pressing force of the cutter drum 4 against the natural ground (rock mass), the maximum amplitude value of the boom 3 corresponding to the pressing force within each range and the pressing force thereof. It is also possible to set a relational expression for obtaining the compression strength evaluation point from, and calculate the compression strength evaluation point from the relational expression corresponding to the pressing force of the cutter drum 4 during excavation. in this case,
The relational expression between the maximum amplitude value of the boom 3 and the pressing force of the cutter drum 4 and the compression strength evaluation point is the result of the multiple regression analysis, and
The compression strength evaluation point is calculated by this formula.

[Equation 6] Y = A × X1 + B × X2 + C ... In the relational expression shown in Equation 6, Y: compressive strength evaluation point, X1: pressing force, X2: maximum amplitude value, A, B, C : It is a coefficient.

For example, the pressing force of the cutter drum 4 is 4.0 to
Divide into ranges such as 6.0MPa, 6.0 to 8.0MPa, 8.0 to 10.0MPa, analyze the relationship between the compression strength evaluation points from the maximum amplitude value of boom 3 and its pressing force in each range, and analyze as described above. The conversion formula is set, and the compression strength evaluation point is obtained from the maximum amplitude value and the pressing force using the relational expression corresponding to the pressing force of the cutter drum 4 when the tunnel is excavated by the free section excavator 1. FIG. 9 shows the procedure for obtaining the compression strength evaluation points by this method.

Furthermore, the actual pressing force of the cutter drum 4 is
Graph of the compressive strength evaluation point obtained from the pressing force and the maximum amplitude value of the boom 3 corresponding to this pressing force in the case of 6.0 to 8.0 MPa, and the compressive strength evaluation point obtained by evaluating the measurer Is shown in FIG. In addition, when the actual pressing force of the cutter drum 4 is 8.0 to 10.0 MPa, the compression strength evaluation point obtained from the pressing force and the maximum amplitude value of the boom 3 corresponding to this pressing force, and the measurer evaluated it. A graph with the compression strength evaluation points obtained by the above is shown in FIG. Furthermore, the compressive strength evaluation points obtained from the pressing force and the maximum amplitude value corresponding to this pressing force, and the compressive strength evaluation points obtained by evaluating the measurer are arranged, and the result is shown as a graph in FIG. . From this FIG. 12, it can be understood that the compression strength evaluation point obtained from the pressing force and the maximum amplitude value and the compression strength evaluation point obtained by the evaluation by the measurer are substantially the same.

The procedure for measuring the amplitude of the boom during the excavation by the excavator and obtaining the compression strength evaluation point from the maximum amplitude value has been described above, but the overall evaluation point of the rock mass is calculated from the maximum amplitude value of the boom. The method of obtaining can be performed by the same procedure.

[Brief description of drawings]

1 is a simplified side view of a free-section excavator,

FIG. 2 is a diagram showing the relationship between the maximum amplitude value of the boom and the compression strength evaluation point,

FIG. 3 is a relational diagram between a maximum amplitude value created from a conversion formula and a compression strength evaluation point,

FIG. 4 is a block diagram of processing and displaying various data on the excavator side,

FIG. 5 is a diagram showing a case where there is a difference in the correlation between the maximum amplitude value and the compression strength evaluation point,

FIG. 6 is a diagram for explaining a correction method,

FIG. 7 is a relational diagram of the maximum amplitude value and the compression strength evaluation point when corrected,

FIG. 8 is a block diagram showing a procedure for converting a maximum amplitude value into a compression strength evaluation point,

FIG. 9 is a block diagram showing a procedure for converting a maximum amplitude value and a pressing force into a compression strength evaluation point,

FIG. 10 is a diagram showing a compression strength evaluation point obtained from a pressing force in a certain range and a maximum amplitude value, and a compression strength evaluation point by a measurer;

FIG. 11 is a diagram showing a compression strength evaluation point obtained from a pressing force in a certain range different from the above and a maximum amplitude value, and a compression strength evaluation point by a measurer;

FIG. 12 is a diagram of compression strength evaluation points obtained from actual values of pressing force and maximum amplitude value.

[Explanation of symbols]

1 Free section excavator 3 boom 4 cutter drum 5 acceleration converter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Gen Hamada             2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi             Inside the Okumura group (72) Inventor Mitsuyoshi Takemoto             2-2-2 Matsuzaki-cho, Abeno-ku, Osaka-shi             Inside the Okumura group F-term (reference) 2D054 AC20 BA23 GA10 GA15 GA17                       GA62 GA64 GA66 GA72 GA83                       GA92                 2G064 AA11 AB02 AB07 AB08 AB24                       BA02 CC56 CC58

Claims (6)

[Claims] 1. When excavating rock by pressing the excavation means provided at the tip of the boom against the rock, the vibration value of the boom during excavation is measured and the rock evaluation point is calculated from the vibration data. Evaluation method of tunnel excavation ground characteristics. 2. The method for evaluating the property of a tunnel excavated ground according to claim 1, wherein the vibration value of the boom is a maximum amplitude value. 3. A measured value of the pressing force of the excavating means during rock excavation, which is obtained by obtaining a reference value of the maximum amplitude value of the boom corresponding to the reference value of the pressing force of the boom tip excavating means against the rock. The maximum amplitude value of the boom is corrected by obtaining a converted value of the maximum amplitude value from the calculated value and adding the difference between the converted value and the reference value of the maximum amplitude value to the measured value of the maximum amplitude value. Alternatively, the property evaluation method of the tunnel excavated ground according to claim 2. 4. A conversion formula between the maximum amplitude value of the boom corresponding to the pressing force within each range and the rock mass evaluation point is set for each fixed range of the pressing force of the boom tip excavating means against the rock, The method for evaluating the property of a tunnel excavated ground according to claim 1 or 2, wherein an evaluation point of the bedrock is calculated by a conversion formula corresponding to the pressing force of the excavating means at the time of excavation. 5. A relational expression for obtaining a rock mass evaluation point from the maximum amplitude value of the boom corresponding to the pressing force within each range and the pressing force for each fixed range of the pressing force of the boom excavating means against the rock mass. The property evaluation method of the tunnel excavated ground according to claim 1 or 2, wherein the evaluation point of the rock mass is calculated in advance by a relational expression corresponding to the pressing force of the excavation means at the time of excavation. 6. The evaluation point of the rock mass is an evaluation point of compressive strength, as claimed in any one of claims 1 to 5.
The property evaluation method for a tunnel excavated ground according to any one of items.