JP3721486B2 - Evaluation method of ground in tunnel excavation and tunnel excavation method using it - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to a technical field of a ground excavation method in tunnel excavation using a full-section tunnel excavator (hereinafter referred to as TBM: tunnel boring machine) and a tunnel excavation method using the same .
[0002]
[Prior art]
The TBM excavation method is capable of high-speed excavation without support if it is blessed with natural ground conditions, and can fully utilize its advantages, but poor geological areas such as aquifer mountains and fault fracture zones with low consolidation Drilling is not good, and troubles caused by these often occur, and TBM often stops for several months. In order to prevent TBM troubles caused by such geological factors, it is necessary to know in advance the changes in the stratum structure of the front rocks in front of the face and the geological properties and scales of the defective geological areas. There is a need for a TBM excavation system that can correctly evaluate and select countermeasures and auxiliary construction methods, and determine whether TBM excavation is possible.
[0003]
Conventionally, as a method for predicting the face ahead of the face, for example, in JP-A-4-161588, drilling data by a hydraulic percussion drill (a drilling depth obtained by drilling, a cumulative drilling time at each depth, a drilling hole, We propose a method to calculate the fracture energy by speed, piston impact energy, feed force, torque, water supply pressure, etc.) and to make a prediction in relation to the rock grade by the probability statistical method.
[0004]
[Problems to be solved by the invention]
However, although the prediction method using the percussion drill is an effective method in the case of the blasting method, in the case of TBM, the drilling must be interrupted and a percussion drill must be installed on the face, and during boring There is a problem that the construction period is greatly extended because TBM excavation is not possible, and there is a problem of TBM cutter breakage when the rod is bitten in a natural ground and the rod must be thrown into the natural ground, and the above method is adopted for TBM excavation It is difficult to do.
[0005]
In order to solve this problem, in the Japanese Patent Application No. 9-139693, the present inventors can investigate and evaluate natural ground in front of the face by advanced boring from the inside of the TBM machine, and can discriminate natural ground properties with high accuracy. At the same time, we have applied for a tunnel excavation system that can select appropriate support and auxiliary methods according to the natural ground properties and can perform reliable TBM excavation.
[0006]
The present invention further improves the above-mentioned invention of the prior application, indexes a part of TBM machine data to be measured in real time to excavation energy, gripper coefficient, and the like, and evaluates criteria determined in advance prior to the underground observation survey at the time of pulling the rear body of the TBM It is an object of the present invention to provide a tunnel excavation system capable of predicting a ground grade based on the above and thereby constructing an appropriate support pattern in a timely manner.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the method of evaluating the ground in front of the face in tunnel excavation according to the first aspect of the present invention includes a cylindrical skin plate, a cutter head rotatably attached to the tip of the skin plate, and a rear part in the machine. A full-section tunnel excavator (TBM) equipped with a thrust jack, a main gripper , and an advanced boring device installed in the TBM, the drilling speed obtained from the advanced boring investigation by the advanced boring device , A first evaluation step for calculating fracture energy using the cross-sectional area of the drilling hole, and evaluating a natural ground property in front of the face according to an evaluation standard set by the fracture energy, torque, and driving force , and then the entire cross-section tunnel Drilling speed, cutter rotation speed, cutter torque, propulsion thrust force, main grind obtained by excavating with the excavator Stress during overhang - is calculated drilling from strain characteristic energy and gripper coefficient, a second evaluation step of evaluating the natural ground properties of tunnel face by criteria set by the drilling energy and the gripper coefficient, the second evaluation And a feedback step for reviewing the first evaluation standard based on the above .
The tunnel excavation method using the full-section tunnel excavator of the second invention is characterized by selecting a support structure by natural ground evaluation using the natural ground evaluation method of the first invention and tunneling .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1-10 shows one Embodiment of the tunnel excavation system of this invention, FIG. 1 is a schematic diagram of TBM used by this invention.
[0009]
In FIG. 1, the TBM 1 includes a cylindrical skin plate 3, a cutter head 2 that is rotatably mounted at the tip of the skin plate 3, a thrust jack 4 and a main gripper 5 that are installed at the rear of the machine, and the main gripper 5. The cutter head 2 is rotated while the thrust jack 4 is extended by taking a reaction force on the well wall and excavating one stroke. A rotary percussion drill 6 is installed on the thrust jack 4. The rotary percussion drill 6 has a non-core boring mode in which a drill bit is drilled while rotating and rotating the tip bit, and a partial core boring mode in which the tip core is taken while the bit is changed and the drill is struck and rotated. The percussion drill 6 is installed so as to be swingable in the vertical and horizontal directions, and as shown by the dotted line in the figure, the inside face boring 8 drilled in the direction perpendicular to the face surface 7 and the skin plate 3 as shown by the solid line in the figure. An outer face boring 9 that is drilled from the rear end obliquely forward of the face is made possible.
[0010]
FIG. 2 is a diagram for explaining the system configuration and evaluation items of the present invention. In the present invention, the TBM excavation evaluation items are grasped from the advanced boring survey and the TBM machine data, and the support pattern is finally evaluated. Of course, data from conventional underground observation surveys and mechanics surveys / tests are also added to the evaluation criteria as needed. TBM excavation evaluation items are (1) grasp of geological change and excavation speed, (2) grasp of stability of top and shoulder, (3) grasp of stability of side wall, (4) well spring water It consists of evaluation, (5) evaluation of defective geology, and (6) support pattern evaluation.
[0011]
In the advanced boring survey, (1) drilling depth, (2) drilling speed, (3) feed force, (4) impact energy, (5) number of hits, (6) torque, (7) rotational speed, (8) Acquire data such as water supply pressure and (9) water supply amount, index these data as destruction energy, and evaluate evaluation items (1) to (6) based on these data and destruction energy. In addition, the evaluation items (1), (4), (5) are based on observations of the color of the slime, the shape, type, size, and hardness of the rock fragments, the determination of the geology by collecting partial cores, and the measurement of the amount of spring water in the borehole. Evaluate (6).
[0012]
From TBM machine data, (1) excavation speed, (2) cutter rotation speed, (3) cutter torque, and (4) thrust thrust force are obtained, and these data are indexed as excavation energy. Evaluation items (1) to (6) are evaluated based on energy.
[0013]
(5) Calculate the front gripper coefficient and evaluate the evaluation item (2). (6) Calculate the left and right main gripper coefficients and evaluate the evaluation item (3).
[0014]
FIG. 3 is a flowchart showing an example of data processing of the tunnel excavation system of the present invention. First, in step S1, a geological survey point in front of the face is specified from a geological book or the like, and then a TBM excavation is performed in step S2 to the survey point. In step S3, TBM machine data such as excavation speed, cutter torque, thrust thrust, etc. is obtained. get. In step S4, in parallel with the TBM excavation, boring 9 (about 50 to 100 m) is performed obliquely forward with the rotary percussion drill 6 in the non-core boring mode, and boring drilling data is acquired in step S5. This drilling data includes (1) drilling depth, (2) drilling speed, (3) feed force, (4) impact energy, (5) number of impacts, (6) torque, and (7) rotational speed. , (8) water supply pressure, and (9) water supply amount. Next, in the data analysis / plotting means in step S6, based on the boring data, (1) depth change analysis, (2) correlation analysis between data, (3) measurement data indexing, (4) Estimate mechanical parameters. These contents will be described below.
[0015]
(1) Analysis of change in depth For example, a Gaussian model shown in FIG. 4 (B) or FIG. 4 (C) using a known probability / statistical method from data of change in measured value with respect to the drilling depth shown in FIG. 4 (A). The non-Gaussian model shown in Fig. Thereby, it becomes possible to recognize easily the change of the measured value with respect to the drilling depth.
[0016]
(2) Correlation analysis between data (1) It is possible to estimate the hardness of the formation from the correlation between drilling speed and impact energy x the number of impacts.
(2) The rocky state can be estimated from the correlation between drilling speed and feed force.
(3) The formation collapse can be estimated from the correlation between drilling speed and torque x rotation speed.
(4) The type of rock can be estimated from the correlation between torque × rotational speed and impact energy × number of impacts. (5) The rock type and hydrogeological structure can be estimated from the correlation between the water supply pressure and the water supply volume.
[0017]
(3) Indexing measurement data Fracture energy EP (kgf · cm / cm ² / cm ² )
EP = impact energy (kgf · cm) × number of impacts (bpm) / drilling speed (cm / min) / drilling cross-sectional area (cm ² )
2. Drilling energy ^{Et (kgf · cm / cm 2} / cm): Energy Et = El / A necessary for drilling a unit volume
E1: Energy required for excavation of unit cm (kgf · cm / cm)
E1 = thrust thrust (tf) × 1000 + [ 2π × cutter rotation speed (rpm) × cutter torque (tf · m) × 1000 × 100] / [digging speed (mm / min) × 0.1]
A: Drilling cross section (cm ² )
3. Gripper coefficient Gc (kgf / cm ² )
Strain εj (stroke δj / excavation radius r) is taken on the horizontal axis, and gripper loading stress σj is taken on the vertical axis, and the stress-strain characteristics when the gripper is extended are quantified. The value of the gripper coefficient is calculated from the following equation.
[0018]
Gc = ([sigma] m + 2- [sigma] m-2) / ([epsilon] m + 2- [epsilon] m-2) ( where m represents the number of intermediate pitches of the stroke when the gripper is extended ) .
εj = δj / r
j = 1, number of stations (4) Estimate of mechanical parameters Uniaxial compressive strength of rock mass = k × fracture energy Next, in the natural ground evaluation means in step S7, referring to the correlation between the measured data, etc. Within the borehole data, the geological structure, rock type, rock mass, etc. are classified, identified, and judged by the expert from the TBM site based on changes in the depth axis such as fracture energy, drilling speed, torque, and advance force. Create a mountain evaluation chart.
[0019]
Next, in step S8, it is determined whether or not to perform core boring in the face if the ground is defective and it is desired to investigate in more detail. If YES, core boring in the face is performed, and in step S10 Core boring data is acquired, and the formation structure is determined again in steps S5 to S7 based on this data. Then, based on the determined stratum structure, a support construction and an auxiliary construction method are selected in step S11. Next, in step S12, whether or not TBM excavation is possible is determined. If it is determined that TBM excavation is possible, the process returns to step S2, TBM excavation is performed, and if it is determined that TBM excavation is impossible, in step S13 Evaluation is performed, trouble estimation, countermeasure work, and preliminary ground reinforcement work are performed, and the process returns to step S2 to perform TBM excavation.
[0020]
FIG. 5 is a diagram for explaining natural ground evaluation by advanced boring in step S7, selection of a support work and selection of an auxiliary method in step S11. Note that the borehole drilling data evaluation reference value, the support structure, and the auxiliary method are merely examples, and are not limited thereto. Depending on the measured drilling speed, torque, feed force and the fracture energy value calculated from the measured data, it is divided into 5 levels from 1 to V, and appropriate support according to each level. Selection of construction method, selection of auxiliary construction method, and TBM excavation method are selected. The all-around simple liner is a method in which a liner piece is assembled over the entire circumference of the well wall, and the shield jack is a method in which a propulsion reaction force is applied to this all-around simple liner. The backfill injection is a method in which mortar is injected between the liner and the pit wall, and the face injection is a method in which cement milk or urethane material is injected from the inside of the machine into the face and the surrounding ground.
[0021]
6A and 6B are diagrams for explaining the simplified prior support system of FIG. 5, FIG. 6A is a cross-sectional view of the TBM, and FIG. 6B is a cross-sectional view of the tail portion of the skin plate. . In this system, when the cutter head 2 digs up for one stroke, the front receiving material 11B is received by the ring support 12 immediately behind the tail portion of the skin plate 3, and the front gripper 13 installed on the inverse liner 15 is extended. It is pressed and supported, and is fixed to the ring support 12 on the front by a tie rod 16. Next, the next receiving material 11A is inserted into the space between the skin plate 3 and the pit wall at a space between the existing receiving material 11B, and the fiber blowing mortar 20 is applied to the pit wall surface. As described above, since the back of the skin plate 3 is always supported by the receiving material, it is possible to prevent the skin from falling off.
[0022]
FIG. 7 is a perspective view of the open liner system of FIG. In this system, liner members 21a, 21b, and 21c that support a part of the tunnel top end are disposed between adjacent ring support members 12 to stabilize the tunnel top end, and to promote the reaction force of the shield jack. It is something to take. Depending on the strength of the ground, a plate-like liner member 21a, a liner member 21b having a partial space, and a wire mesh-like liner member 21c are prepared.
[0023]
Fig. 8 shows an example in which the natural ground division, support structure, auxiliary construction method, and excavation method change according to the drilling depth of advanced boring, predicting the natural ground properties in front of the face as much as possible from inside the TBM machine, By selecting an appropriate support structure and auxiliary construction method according to the mountain properties, a reliable excavation can be performed.
[0024]
FIG. 9 is a diagram showing changes in excavation energy, front gripper coefficient, and main gripper stroke, which are index values of TBM machine data. In the figure, 2 is a cutter head, 5 is a main gripper, and 13 is a front gripper.
[0025]
FIG. 10 is a diagram for explaining an evaluation method in the tunnel excavation system of the present invention. FIG. 10 (A) shows an example of evaluation standard of ground level from the excavation energy and gripper coefficient based on the TBM machine data described above, and FIG. 10 (B) is a ground level from the advanced boring survey explained in FIG. An example of evaluation criteria is shown.
[0026]
In the present invention, first, the natural ground grade is evaluated based on the advanced boring survey, and then the natural ground grade is evaluated based on the actual TBM machine data. Based on the evaluation result, the natural ground grade based on the previous advanced boring survey is evaluated. The evaluation standard is reviewed, and the natural ground evaluation standard can always be set by the latest information by learning with this feedback system.
[0027]
【The invention's effect】
As is clear from the above description, according to the present invention, a part of the TBM machine data of the real-time measurement is indexed by the excavation energy and the gripper coefficient, thereby making it possible to discriminate by the numerical value of the ground grade. Therefore, it is possible to select an appropriate support structure and auxiliary method according to natural ground properties, and to perform reliable TBM excavation. In addition, since the natural ground property can be predicted before the rear trunk of the TBM is drawn, an appropriate support pattern according to the natural mountain property can be selected. Furthermore, the prediction accuracy of the natural ground grade from the advanced boring survey results is learned by reviewing the natural ground evaluation standard by feedback of TBM machine data, and the natural ground property can be predicted and evaluated with high accuracy and the latest information.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a TBM used in the present invention.
FIG. 2 is a diagram for explaining a system configuration and evaluation items in the present invention.
FIG. 3 is a flowchart showing an example of data processing of the advanced boring survey in FIG. 2;
FIG. 4 is a diagram for explaining data plotting;
FIG. 5 is a diagram for explaining natural ground evaluation by advanced boring, selection of a support structure, and selection of an auxiliary method.
6A and 6B are diagrams for explaining the simplified prior support system of FIG. 5, in which FIG. 5A is a cross-sectional view of the TBM, and FIG. 5B is a cross-sectional view of the tail portion of the skin plate.
7 is a perspective view showing the open liner system of FIG. 5. FIG.
FIG. 8 is a diagram showing an example in which the natural ground division, the support structure, the auxiliary construction method, and the excavation method change according to the drilling depth of the boring.
FIG. 9 is a diagram showing changes in excavation energy, front gripper coefficient, and main gripper stroke, which are index values of TBM machine data.
FIG. 10 is a diagram for explaining an evaluation method in the tunnel excavation system of the present invention.
[Explanation of symbols]
1 ... TBM (Tunnel excavator with full cross section)
2 ... Cutter head 5 ... Main gripper 6 ... Advanced boring device 7 ... Face face 8, 9 ... Advanced boring 13 ... Front gripper

Claims (2)

A cylindrical skin plate, a cutter head rotatably mounted at the tip of the skin plate, a thrust jack placed at the rear of the machine, a full-section tunnel excavator (TBM) equipped with a main gripper , and installed in the TBM It is equipped with an advanced boring device , and the fracture energy is calculated using the drilling speed, the number of hits, and the cross-sectional area obtained from the advanced boring survey by the advanced boring device , and is set by the fracture energy, torque, and feed force The first evaluation step to evaluate the natural ground properties in front of the face according to the evaluation criteria , and then the excavation speed, cutter rotation speed, cutter torque, propulsion thrust force, main gripper overhang obtained by excavation by the full-section tunnel excavator The drilling energy and gripper coefficient are calculated from the stress-strain characteristics of the A second evaluation step of evaluating the natural ground properties of tunnel face by criteria set by formic and gripper coefficient, and characterized by comprising feedback step of, reviewing the first evaluation criterion to the second based on the evaluation of A natural ground evaluation method in front of the face in tunnel excavation. A tunnel excavation method using a full-section tunnel excavator, wherein the tunnel excavation method is carried out by selecting a support structure based on an evaluation of a natural ground using the natural ground evaluation method according to claim 1. .

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