JP3213261B2 - Detecting looseness of tunnel excavation wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting a property of a wall surface of a tunnel excavation, that is, a loose state when a tunnel excavator excavates a tunnel in a bedrock.

[0002]

2. Description of the Related Art When a tunnel is formed while excavating bedrock by a tunnel excavator, the excavated tunnel wall surface may fall off or fall down. At the rear, the loosened state of the tunnel excavation wall is detected, and a support is formed according to the loosened state.

[0003]

However, the detection of the loosened state of the tunnel excavation wall is performed on the tunnel excavation wall exposed behind the tunnel excavator. When the lining member is stretched, there is a risk that the rock may collapse, and there is a problem that the construction work is extremely dangerous. Furthermore, since the method of detecting the loosened state of the tunnel excavation wall is performed visually,
Not only does it require a great deal of experience, but it also makes accurate judgment difficult.Therefore, in order to ensure safety, it is necessary to construct shoring with strength greater than necessary, which increases the cost and reduces work efficiency. There was a problem of doing.

[0004] The present invention has been made in view of such problems, and an object of the present invention is to accurately detect a loosened state of a tunnel digging wall on a tunnel digging machine side and detect a tunnel digging wall behind a tunnel digging machine. Another object of the present invention is to provide a method for detecting a loosened state of a tunnel excavation wall surface, which can make it possible to construct a support having a form corresponding to a loosened state more safely and more efficiently than before.

[0005]

According to a first aspect of the present invention, there is provided a method for detecting a loosened state of a tunnel excavation wall, wherein a roof is provided on at least an upper peripheral portion of the tunnel excavation wall. the load applied to the roof measured during tunnel excavation Te, tunneling walls of detecting the slack condition of the tunnel boring wall on the magnitude of the load that the measured
A method for detecting a loose state of a surface, wherein the roof is vertically supported by a hydraulic jack with respect to an upper portion of a tunnel excavator, and the hydraulic jack is extended to press the roof against a tunnel excavation wall surface. Thereafter, the hydraulic jack is contracted to release the pressure contact of the roof from the tunnel excavation wall surface, and the operating oil pressure of the hydraulic jack when the pressure contact force is released is measured. It is characterized by detecting.

[0006]

[Operation and Effect] The roof provided on the tunnel excavator is pressed against the tunnel excavation wall surface to support the exposed rock. In this case, the surface of the tunnel excavation wall may easily fall off or collapse due to loosening of the bedrock from the upper periphery, so that at least the upper periphery of the tunnel excavation wall may be supported by the roof. When the roof is supported by the tunnel excavation wall, in the case of stable rock that does not loosen, if the roof is slightly lowered from the state where the roof is pressed against the tunnel excavation wall, the load on the roof from the tunnel excavation wall side In the case of disintegrating rock mass which is loosened, even if the roof is slightly moved downward from the state where the roof is pressed against the tunnel excavation wall surface, a load corresponding to the magnitude of the looseness is applied to the roof due to the looseness of the rock mass. By measuring this load, the loose state of the rock on the wall of the tunnel excavation can be quantitatively and simply and accurately detected, and early detection is possible, so that the rock in the loose state can be dealt with accurately and efficiently.

Further, since the detection of the looseness of the rock on the wall of the tunnel excavation is performed by the roof covering the tunnel excavator as described above, it is safer than the conventional method of directly determining the exposed rock on the wall of the tunnel excavation. In addition, it is possible to detect whether there is looseness in the bedrock of the tunnel excavation wall portion supported by the roof, that is, to detect whether there is a possibility of skin fall or collapse, Supporting means corresponding to the loosened state of the tunnel excavation wall portion can be selected. It is possible to construct the support selected above on the tunnel excavation wall part, and it is not necessary to construct a support with strength greater than necessary. It also may be applied be efficiently support Engineering optimum structure corresponding to loosening state of the tunnel excavation wall.

Further, as a means for detecting the loosened state of the tunnel excavation wall, the above-mentioned roof is supported above the tunnel excavator by a hydraulic jack, and the hydraulic jack is extended to press the roof against the tunnel excavation wall. ,
The hydraulic jack is contracted to release the pressure contact of the roof from the tunnel excavation wall surface, the operating oil pressure of the hydraulic jack at this time is measured, and the state of loosening of the tunnel excavation wall surface is detected from the magnitude of the hydraulic pressure value. It is possible to quantitatively and steplessly detect the state of loosening of the tunnel excavation wall surface.If the looseness is small, use lining with shotcrete as a support means. It is possible to adopt an appropriate form of support such as assembling the support by a ring made of a ring, reducing a pitch between the supports, or using a segment or using a lock bolt.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a tunnel excavator A provided with a roof 2 supporting an upper peripheral portion of a tunnel excavation wall surface t. The tunnel excavator A is formed to have a diameter smaller than the tunnel diameter and rotatably supports a cutter plate 3 for excavating a tunnel at the front surface thereof; A beam body 4 of a fixed length extending horizontally in the tunnel length direction from the back of the excavator body 1 to the rear, and a jack 5a which projects downward from the lower surface of the excavator body 1 and extends and contracts. A front support 5 to be extended, and a rear support 6 projecting downward from the lower surface of the rear end of the beam body 4 and being vertically expandable and contractable by a jack 6a.
, A rear gripper 7 slidably mounted along the lower surface of the beam body 4, and a propulsion jack 8 connecting the excavator body 1 and the rear gripper 7.

The rear grippers 7 are disposed on the rear side of the beam member 4 and are provided on both lower surfaces of a beam receiver 9 slidable relative to the beam member 4 as is well known. The two rear grippers 7, 7 are connected to both sides of the rear surface of the excavator body 1 by the propulsion jacks 8, 8, respectively. Note that a rotary drive mechanism (not shown) for the cutter plate 3 is provided in the excavator body 1.

The roof 2 is formed in an arc shape in cross section along a circumferentially curved surface of an inner peripheral wall of an upper peripheral portion of the tunnel excavation wall surface t.
Is formed to have a width capable of supporting at least the upper peripheral portion of.
The roof 2 is supported on a front upper surface of the beam body 4 of the tunnel excavator A via a link 10 and a hydraulic jack 11.

As shown in FIG. 2, this support structure pivots the upper end of the link 10 and the hydraulic jack 11 in the front-rear direction with a small front-rear space on the lower surface near the center of the roof 2 in the longitudinal direction. The links 10 and the hydraulic jack 11 are freely pivoted 12 and 13, and the links 10 and the hydraulic jacks 11 are expanded and inclined in a lateral C-shape in a direction away from the pivots 12 and 13 toward the lower end, and are inclined. The lower end is pivotally attached to the front end of the upper surface of the beam body 4 so as to be freely rotatable, and the lower end (tip) of the hydraulic jack 11 inclined in the direction opposite to the link 10 is moved rearward from the lower end pivoting portion 14 of the link 10. The beam member 4 is pivotally mounted 15 on the upper surface of the beam member 4 at a predetermined interval so as to be rotatable in the front-rear direction.

The hydraulic jack 11 is, as shown in FIG.
Hydraulic oil supply device installed at the right place in tunnel excavator A
Pressure oil is supplied through a pressure oil pipe 17 connected to a pressure oil pipe 16. An oil pressure gauge 18 is provided in the pressure oil pipe 17 to detect a rock state loosening state detecting means on the tunnel excavation wall t together with the roof 2. Make up.

The tunnel T is excavated by the tunnel excavator A equipped with the rock state looseness detecting means having the above structure, and the loose state of the tunnel excavation wall surface t is detected. A method of forming a support in a loose state, that is, a structure according to properties, will be described.
The right and left rear grippers 7, 7 are stretched while the beam receiver 9 is drawn to the front side of the beam body 4 along the beam body 4 to be pressed against the tunnel excavation wall surface t, while the rear support 6 is It is separated upward from the bottom surface of the excavation wall t. Furthermore, the roof 2 is brought into close or sliding contact with the upper peripheral wall surface of the tunnel excavation wall surface t without being pressed against it, so that the rock pieces are prevented from falling into the machine.

In this state, when the propulsion jacks 8, 8 are extended while rotating the cutter plate 3, the excavator body 1 moves forward while the front support 5 slides along the bottom surface of the tunnel excavation wall surface t. Face rock is excavated by the plate 2. When a tunnel T having a predetermined length is excavated, excavation by the excavator body 1 is stopped, and then the hydraulic oil is supplied from the hydraulic oil supply device 16 to the hydraulic jack 11 through the hydraulic oil pipe 17, and the operating oil pressure causes the hydraulic jack 11 to operate. By extending the rod and rotating the link 10 in the upright direction, the roof 2 is moved upward and pressed against the tunnel excavation wall surface t.

Then, when the supplied pressure oil amount reaches a certain amount, the supply of the pressure oil is stopped, and the operating oil pressure at this time is detected by the oil pressure gauge 18. The detected oil pressure value is the tunnel excavation wall t
It depends on the quality of the rock. In other words, the more stable the rock,
The oil pressure value is large, and the oil pressure value is small as it is loose. As described above, the degree of loosening of the rock is detected by the magnitude of the hydraulic pressure value when the roof 2 is pressed against the tunnel excavation wall surface t with a certain amount of pressure oil.

From this state, the working pressure oil supplied to the hydraulic jack 11 is gradually returned to the pressure oil supply device 16 and the hydraulic jack 11
When the pressing force of the roof 2 against the tunnel excavation wall surface t is released by contracting the rod, the roof B2 of the tunnel excavation wall surface t is stable as shown in FIGS. The hydraulic pressure corresponding to the own weight of the roof 2 is displayed on the oil pressure gauge 18 without applying a load from the tunnel excavation wall t side, and the tunnel excavation wall t pressed by the roof 2 is a stable ground. Can be determined.

On the other hand, as shown in FIG. 4, when the rock B2 on the tunnel excavation wall surface t against which the roof 2 is pressed is loose, the working pressure oil for the hydraulic jack 11 is gradually supplied to the pressure oil supply device 16 from the pressed state. By returning, the rod of the hydraulic jack 11 is contracted, and as shown in FIG.
Even if the pressure contact of the roof 2 to the roof 2 is released, since the loose load of the loose rock B2 is acting on the roof 2, the hydraulic pressure equivalent to the sum of the own weight of the roof 2 and the loose load is applied to the hydraulic pressure gauge 18 Will be displayed.

At this time, since the weight of the roof 2 is constant, a value obtained by subtracting a value corresponding to the weight of the roof 2 from the value displayed on the oil pressure gauge 18 indicates the magnitude of the loose load. The magnitude of this loose load value is proportional to the magnitude of the degree of looseness, such as a loose state in which the tunnel excavation wall surface t easily falls or a loose state in which it easily collapses. By calculating, the magnitude of the looseness of the rock on the tunnel excavation wall surface t at the site is known. Furthermore, if the roof 2 is divided into a plurality of parts in the circumferential direction or the length direction of the tunnel, and a hydraulic jack is attached to each of the divided roofs, the loose state of the rock can be grasped more accurately.

On the other hand, as the tunnel excavator A excavates, a tunnel excavation wall t exposed from the rear end of the roof 2 of the tunnel excavator A is provided with a support for preventing the rock from falling off or falling down from the tunnel excavation wall t. Is constructed. As the form (pattern) of this support, there are various types of supports that are constructed according to the size of the loosened state of the rock on the tunnel excavation wall t from the stable rock which does not necessarily require the support at all. As such a support form, the following support is generally employed for the tunnel excavation wall t as the rock state of the rock on the tunnel excavation wall t increases from small to large.

That is,. Lining with sprayed concrete,. Combination of this sprayed concrete lining and steel ring support. Narrow the pitch between the steel ring supports in the form of support,
. Combined with lock bolts to be installed on the tunnel excavation wall surface t in the form of support. In the form of support, the spacing between the lock bolts is reduced. Support by assembling steel liners (steel segments),.
In addition, a construction form in which rock bolts are used together is adopted.

The detection of the looseness of the rock on the tunnel excavation wall surface t is performed as described above by the roof 2 disposed in front of the support construction site. While exposing to the rear of the roof 2 according to the excavation of A, it is possible to select an appropriate supporting form according to the degree of looseness of the rock on the tunnel excavation wall portion, and the tunnel excavation wall portion is moved from the rear end of the roof 2 When exposed to the rear, it is possible to quickly construct a support form according to the looseness of the rock part. In addition, when it is detected that the loose load is particularly large, a steel liner is assembled in the roof 2 and the support is constructed without exposing the excavation wall surface.

When the roof 2 is pressed against the tunnel excavation wall surface t and the rock state thereof is detected, the tunnel excavator A is stopped and the rear support 6 is extended to thereby lower the lower end surface of the tunnel excavation wall t. Crimp to the bottom of
The excavator body 1 and the beam body 4 are supported together with the front support 5. Then, after detecting the loosened state of the rock on the tunnel excavation wall surface t at the place where the tunnel excavator A stops, when excavating the next tunnel of a certain length,
After releasing the pressure from the rear gripper 7 against the tunnel excavation wall t, the propulsion jack 8 is contracted to
Then, as described above, the rear brick 7 is pressed against the tunnel excavation wall surface t and the rear support 7 is separated upward from the tunnel excavation wall surface t, and the propulsion jack 8 is rotated while rotating the cutter plate 3 in this state. The tunnel T is extended and excavated.

The detection of rock looseness on the tunnel excavation wall surface t is performed every time a tunnel of a fixed length is excavated, and as shown in FIG. 1, a steel liner (steel segment) corresponding to the degree of rock looseness. A combination of the support by assembling 19 and the fastening of the steel liner 19 by placing the lock bolt 20 on the excavation wall t, the support form of the steel ring support 21, the lining with sprayed concrete 22, etc. is there.

[Brief description of the drawings]

FIG. 1 is a simplified longitudinal sectional side view of a state where a tunnel is excavated by a tunnel excavator having a roof for detecting a rock loose state,

FIG. 2 is a simplified side view showing a state in which a roof is pressed against rock rock on a stable excavation wall surface,

FIG. 3 is a simplified side view showing a state in which a pressing force of a roof is released from an excavation wall surface,

FIG. 4 is a simplified side view showing a state in which a roof is pressed against an excavation wall surface having collapsible rock;

FIG. 5 is a simplified side view showing a state in which a pressure contact force of a roof is released from an excavation wall surface.

[Explanation of symbols]

 A Tunnel excavator 1 Excavator body 2 Roof 11 Hydraulic jack 16 Pressure oil supply device 17 Pressure oil piping 18 Oil pressure gauge t Tunnel excavation wall B1, B2 Rock

────────────────────────────────────────────────── (5) References JP-A-60-212594 (JP, A) JP-A-8-291689 (JP, A) JP-A-7-4176 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) E21D 9/00 E21D 9/06 301 E21D 9/10

Claims (1)

(57) [Claims] 1. A provided a roof on at least the upper peripheral portion of the tunnel boring wall by measuring the load applied to the roof during excavation of the tunnel, the tunnel excavation for detecting the slack condition of the tunnel boring wall on the magnitude of the load that the measured Loose wall
A state detection method, the roof over the tunnel boring machine
Parts can be moved up and down freely by hydraulic jacks.
The hydraulic jack is extended and the
After pressing the pressure on the tunnel excavation wall,
The roof is pressed from the tunnel excavation wall
Unscrew, measure the operating oil pressure of the hydraulic jack at this time, and
Detecting loose state of tunnel excavation wall from pressure value
Method for detecting looseness of tunnel excavation wall
Law.