JP3788545B2 - Tunnel excavator and skin fall prevention method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tunnel excavator, and more particularly, to a tunnel excavator provided with a gripper that is expanded and contracted by a gripper jack with respect to a tunnel pit wall, and a skin fall prevention method using the tunnel excavator.
[0002]
[Prior art]
Conventionally, as one type of tunnel excavator, for example, a tunnel excavator as disclosed in Japanese Patent Publication No. 62-32319 is known. When excavating natural ground using this type of tunnel excavator, the thrust force is transmitted to the cutter head support by the thrust jack while the main gripper (rear gripper) takes the reaction force against the tunnel wall. Excavation is performed by rotating the cutter head supported by the cutter head support.
[0003]
[Problems to be solved by the invention]
However, as described above, when the gripper is expanded with a uniform pressure and pressed against the tunnel pit wall to obtain a driving reaction force, when excavating a ground layer with poor soil conditions such as a medium hard rock layer or a soft rock layer, There is a problem in that cracks occur in the pit wall and the pit wall collapses. In addition, the collapsed rock fragments are accumulated at the lower part of the tunnel, so that there is a problem that an operator needs to remove them.
[0004]
The present invention adjusts the pressing force of the gripper for the purpose of eliminating such problems when excavating a medium hard rock layer, a soft rock layer, or a natural mountain that is likely to lose skin, and thereby a wall wall It is an object of the present invention to provide a tunnel excavator that can prevent the material from collapsing and a skin wall fall-off prevention method using the tunnel excavator.
[0005]
[Means for solving the problems and actions / effects]
In order to achieve the above-described object, the tunnel excavator according to the present invention is a tunnel excavator provided with a gripper that is expanded and contracted by a gripper jack with respect to the tunnel wall.
The gripper jack is composed of an upper gripper jack and a lower gripper jack, and the upper gripper jack and the lower gripper jack are driven by an independent hydraulic pressure, and the pressure of the upper gripper jack and the lower gripper jack are A hydraulic circuit means capable of individually setting the pressure is provided.
[0006]
In the present invention, when excavating a medium hard rock layer or a soft rock layer where the tunnel wall is likely to crack due to the pressing force of the gripper, the gripper applied to the upper half of the tunnel center where the tunnel wall is likely to collapse due to the influence of gravity. The pressing force of the gripper is adjusted by the hydraulic circuit means so as to reduce the pressing force and increase the pressing force of the gripper applied to the lower half portion from the center of the tunnel where the pit wall is difficult to collapse. However, the lower half of the pit wall is more likely to collapse than the upper half depending on the condition of the natural ground. In this case, the pressing force applied to the upper half is increased and the pressing force applied to the lower half is decreased. It is also possible. The above-described pressure control of the upper gripper jack and the lower gripper jack can be performed by making the hydraulic circuit of each gripper jack independent. Further, this pressure control can be automatically performed by inserting a plurality of switching valves, pressure switches and the like in the hydraulic circuit.
[0007]
As described above, by reducing the pressure applied to the upper half or the lower half of the tunnel pit wall that tends to collapse, cracks caused by pressing of the gripper and collapse of the mine wall can be prevented. Further, the grip force can be obtained by increasing the pressure applied to the lower half or upper half of the tunnel well wall that is not easily collapsed. Furthermore, by adjusting the pressure applied to the upper half or the lower half of the tunnel well wall, the pressing force can be changed according to the soil layer such as a hard rock layer or a soft rock layer.
[0008]
In the present invention, the tunnel pit wall contact surface of the gripper shoe of the gripper is an R surface in the digging direction, or the front and rear ends of the tunnel pit wall contact surface are R chamfered or C chamfered. preferable. By doing so, it is possible to suppress the local surface pressure generated at both ends of the gripper shoe, and therefore it is possible to prevent the skin of the tunnel pit wall from being caused by the local surface pressure.
[0011]
In this invention, it is preferable that the tunnel well wall contact surface of the gripper shoe of the gripper is an R surface in the vertical direction . In addition, the surface facing the gripper shoe in the gripper shoe fitting portion of the tunnel excavator body to which the gripper shoe of the gripper is fitted may be an R surface. By doing this, when the pressing force of the gripper applied to the upper half portion from the center of the tunnel pit wall and the pressing force of the gripper applied to the lower half portion are different, the galling caused by the gripper shoe or the tunnel excavator body is prevented. Can do.
[0012]
Next, the skin peeling prevention method according to the present invention is a skin wall peeling prevention method using each tunnel excavator,
First, when all gripper jacks for expanding and contracting the gripper are expanded with a weak pressure that does not cause the skin to fall to the maximum extent, and this extension does not provide a gripping force that can withstand the reaction force, It is characterized in that only the gripper jack on the side that is difficult to perform is further subjected to oil pressure to ensure a grip force that can withstand the digging reaction force.
[0013]
According to the present invention, the gripper is first expanded by applying the same weak pressure to all jacks so that the tunnel wall does not fall off. If this expansion allows the tunnel excavator to obtain a gripping force that can withstand the excavation reaction force, excavation is performed. However, if the tunnel excavator cannot obtain a gripping force that can withstand the digging reaction force even by this expansion, apply a higher hydraulic pressure to the gripper jack on the relatively stable side of the natural ground to reduce the digging reaction force. Ensure excavation with sufficient grip.
[0014]
Such pressure control of the upper gripper jack and the lower gripper jack is possible by making the hydraulic circuit connected to each independent, and by using a plurality of switching valves, pressure switches, etc. in this hydraulic circuit, The gripper jack pressure can be automatically controlled.
[0015]
As mentioned above, the upper gripper jack and the lower gripper jack are each extended by applying separate oil pressure, so that the gripper's pressing force is low on the ground where the pit wall tends to collapse. The pressing force of the gripper can be increased at the mountain portion. Therefore, it is possible to prevent skin peeling due to the pressing force of the gripper and to sufficiently obtain the digging reaction force of the tunnel excavator.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, specific examples of the tunnel excavator and the skin fall prevention method according to the present invention will be described with reference to the drawings.
[0017]
1 is a longitudinal sectional view of a tunnel excavator according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is a sectional view taken along the arrow B in FIG. FIG. 4 shows a hydraulic circuit according to this embodiment.
[0018]
The tunnel excavator 1 according to the present embodiment is divided into a front trunk 2 and a rear trunk 3 and is extended and contracted by a thrust jack 4. A cutter head 7 having a large number of disk cutters 6 on the front surface is rotatably supported via a cutter head support 5 provided inside the front side of the front cylinder 2.
[0019]
A main gripper (gripper) P having a gripper frame 9 is installed behind the cutter head support 5. A thrust jack 4 is provided between the cutter head support 5 and the gripper frame 9. Further, the cutter head support 3 is provided with a front gripper 8 that is used to stabilize the excavation during excavation and to support the cutter head support 5 against the tunnel wall at the end of excavation.
[0020]
The main gripper P is in contact with a tunnel pit wall to fix the excavator body 1 and a main gripper shoe (gripper shoe) 10 and a main gripper jack (gripper jack) 11 (upper side) for expanding the main gripper shoe 10. The main gripper jack 11a, the lower main gripper jack 11b) and a hydraulic circuit (FIG. 4) for driving the main gripper jack 11 are provided.
[0021]
As shown in FIG. 2, the shape of the tunnel pit wall contact surface of the main gripper shoe 10 is an R surface with respect to the excavation direction. Further, the shape of the tunnel well wall contact surface of the main gripper shoe 10 is an R surface as shown in FIG. 3A in the vertical direction of the gripper shoe with respect to the extending direction of the main gripper P. Has been. As another embodiment, as shown in FIG. 3B, the shape of the surface facing the main gripper shoe 10 in the fitting portion 1a of the main gripper shoe 10 of the main body of the tunnel excavator 1 may be an R surface. As shown in FIG. 3C, the main gripper shoe 10 and the fitting portion 1a may both be R surfaces.
[0022]
Next, the hydraulic circuit according to this embodiment shown in FIG. 4 will be described in detail. In this hydraulic circuit, the downstream of the pump 13 is branched into a relief valve 14 side and a switching valve 15 side, and a relief valve 14 is installed on the relief valve 14 side to perform maximum hydraulic pressure of the hydraulic circuit and pump protection. On the other hand, a switching valve 15 for switching the direction of pressure oil is installed on the switching valve 15 side, and the downstream of the switching valve 15 is separated into an upper main gripper jack 11a side circuit and a lower main gripper jack 11b side circuit. Yes. Each of these circuits is provided with an upper jack switching valve 12a and a lower jack switching valve 12b. A relief valve 17, an upper main gripper jack 11a, and a pressure switch 20a are arranged in parallel on the downstream side of the upper jack switching valve 12a. Similarly to the downstream side of the upper jack switching valve 12a, the relief valve 17, the lower main gripper jack 11b, and the pressure switch 20b are arranged in parallel on the downstream side of the lower jack switching valve 12b. Yes.
[0023]
Next, a skin fall prevention method using the tunnel excavator 1 configured as described above will be described in detail.
[0024]
When the tunnel excavator 1 is used to excavate, for example, a soil layer in which the upper half of the tunnel pit wall tends to fall off, the hydraulic pressure applied to the upper main gripper jack 11a and the lower main gripper jack 11b is a hydraulic circuit ( Adjust in (Fig. 4).
[0025]
First, the switching valve 15 is set to the B position, the upper jack switching valve 12a and the lower jack switching valve 12b are set to the A position, and the upper main gripper jack 11a and the lower main gripper jack 11b are tunneled at a low pressure. The wall is extended to such an extent that the pit wall does not fall off (the operator's judgment or the pressure setting value of the pressure switch 20a). Thereafter, the upper jack switching valve 12a is switched to the B position to hold the upper main gripper jack 11a at a low pressure (set pressure of the pressure switch 20a). The relief valve 14 is set to a circuit maximum hydraulic pressure, and the pressure switch 20a is set to a pressure at which no skin peeling occurs.
[0026]
Next, only the lower main gripper jack 11b is extended to the set value of the pressure switch 20b with the lower jack switching valve 12b set to the A position, and then the lower main gripper jack 11b is set to a high pressure (pressure switch). 20b (set pressure). In this way, the pressing force of the main gripper applied to the upper half of the tunnel pit wall and the pressing force of the main gripper applied to the lower half are adjusted. However, the pressure setting value of the pressure switch 20b is not less than the pressure setting value of the pressure switch 20a and not more than the pressure setting value of the relief valve 17.
[0027]
As described above, the pressing pressure applied to the part that is easy to remove skin (in this embodiment, the tunnel wall in the upper half of the tunnel center) is lowered, and the part that is difficult to remove skin (in this example, the tunnel wall in the lower half of the tunnel center). ) Is increased, the skin peeling caused by the pressing force of the main gripper shoe 10 can be prevented, and a sufficient excavation reaction force can be obtained.
[0028]
Further, in the present embodiment, as shown in FIG. 3A, the main gripper shoe 10 has an R surface with respect to the extending direction of the main gripper P so that the upper main gripper jack 11a is There is an effect that it is possible to prevent galling caused by the difference between the pressure and the pressure of the lower main gripper jack 11b. In addition, as shown in FIG. 2, the tunnel well wall contact surface of the main gripper shoe 10 is an R surface with respect to the digging direction, so that the surface pressure of the main gripper shoe 10 is made uniform, Since the pressure applied to the wall becomes uniform, it is possible to prevent the skin of the tunnel pit wall from falling due to the local surface pressure. Even when the shape of the rear trunk 3 and the main gripper shoe 10 of the tunnel excavator 1 is the shape shown in FIG. 3B or FIG. 3C, the same effect as described above can be obtained.
[0029]
In this embodiment, the shield type TBM is used. However, the present invention is not limited to this. For example, the shield type TBM can be used for an open type TBM.
[0030]
In the present embodiment, the shape of the tunnel well wall abutting surface of the main gripper shoe 10 is the R surface with respect to the digging direction. It may be chamfered or chamfered.
[0031]
In the present embodiment, the case where the upper half of the pit wall is excavated in a natural ground part where the skin is likely to fall off has been described. It is only necessary to change the set values of the switch 20a and the pressure switch 20b so that the excavation reaction force is applied to the natural mountain part where the skin is easily removed.
[0032]
In the present embodiment, the hydraulic circuit as shown in FIG. 4 is used. However, the arrangement of the relief valve and the switching valve is not limited to this, and the upper main gripper jack and the lower main gripper jack are independent. It is sufficient that the pressure applied to each jack can be set as the circuit.
[0033]
In this embodiment, one set of main gripper shoes 10 is used, but two sets of main grippers may be used. In this embodiment, two upper and lower jacks are used, but a plurality of jacks may be used. In this case, the pressure applied to the natural mountain part where the skin is easily removed is low, and the pressure applied to the natural mountain part where the skin is relatively difficult to remove is used. Is controlled to be high.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a tunnel excavator according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
3 is another example (b), (c) of FIGS. 1 (a) and 1 (a) and FIG. 3 (a).
FIG. 4 is a hydraulic circuit diagram of the present embodiment.
[Explanation of symbols]
1 Tunnel Excavator 2 Front Drum 3 Rear Drum 4 Thrust Jack 5 Cutter Head Support 6 Disc Cutter 7 Cutter Head 8 Front Gripper 9 Gripper Frame 10 Main Gripper Shoe 11 Main Gripper Jack 11a Upper Main Gripper Jack 11b Lower Main Gripper Jack 12a Upper Jack switching valve 12b Lower jack switching valve 13 Pump 14, 17 Relief valve 15 Switching valve 20a, 20b Pressure switch

Claims (5)

In a tunnel excavator provided with a gripper that expands and contracts with a gripper jack against the tunnel wall,
The gripper jack is composed of an upper gripper jack and a lower gripper jack, and the upper gripper jack and the lower gripper jack are driven by an independent hydraulic pressure, and the pressure of the upper gripper jack and the lower gripper jack are A tunnel excavator characterized by providing hydraulic circuit means capable of individually setting the pressure.   The tunnel pit wall contact surface of the gripper shoe of the gripper is an R surface in the digging direction, or both front and rear ends of the tunnel pit wall contact surface are R chamfered or C chamfered. The tunnel excavator according to 1. The tunnel excavator according to claim 1 or 2, wherein a tunnel pit wall contact surface of the gripper shoe of the gripper is an R surface in the vertical direction . Any of the claims 1 to 3 facing surfaces of the gripper shoe in a gripper shoe fitting portion of the tunneling machine body gripper shoe of the gripper is fitted, characterized in that there is a R surface A tunnel excavator as described in Crab. A method for preventing skin peeling of a mine wall using the tunnel excavator according to any one of claims 1 to 4,
First, when all gripper jacks for expanding and contracting the gripper are expanded with a weak pressure that does not cause the skin to fall to the maximum extent, and this extension does not provide a gripping force that can withstand the reaction force, A method for preventing the skin from falling, characterized in that only the gripper jack on the hard-to-reach side is further subjected to oil pressure to ensure a grip that can withstand the reaction force of the digging.

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