JPH04222795A - Further depth vertical shaft construction method by vertical shield machine - Google Patents

Abstract

PURPOSE:To construct efficiently, economically and safely an accessible vertical shaft necessary for constructing a road, railway or underground solid construction in the ground of the further depth of 50-100m. CONSTITUTION:An enclosed and sludge pressure type vertical shield machine 1 is provided downward in a specific position on the ground, and a reaction force device 2 of the same vertical shield machine 1 is provided to excavate downward at a right angle. The diameter of a cutter head 3 is widened at a position of a vertical shaft bottom 6 to excavate a vertical shaft 5 to the specific depth, and the cutter head 3 is driven forward with a specific stroke downward at a right angle to make widening excavation. Structural steels and reinforcing bars are placed to the inside of the widening excavation section 9 mentioned above, and concrete is placed to construct the vertical shaft bottom 6.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention is applicable to
The present invention relates to a method for constructing a deep shaft using a vertical shield machine, which is used to construct an access shaft for constructing roads, railways, or underground three-dimensional space structures at a depth of ~100 m underground.

0002

BACKGROUND OF THE INVENTION Conventionally, as techniques for constructing shaft structures, the following methods have been widely and generally practiced: 1) Cut-and-cut construction method 2) Caisson construction method 3) PC well construction method.

0003

[Problems to be solved by the present invention] The conventional construction methods 1), 2), and 3) have advantages and disadvantages depending on the construction scale and depth, and each construction method is adopted and implemented depending on the situation. has been done. However, in any case, there is no effective way to realize a vertical shaft structure in a deep underground area that reaches 50 to 100 meters below the ground surface and is subject to a large groundwater pressure of 5 to 10 kg/cm2, with a content that satisfies both the construction period and construction cost. There is no construction method. For example, with the open-cut construction method, as the depth increases, countermeasures against groundwater and groundwater pressure become important issues, which increases costs. The caisson construction method and the PC well construction method are capable of constructing deep shafts to a certain extent, but there are major problems in construction accuracy and cost.

0004

[Means for Solving the Problems] As a means for solving the above-mentioned problems of the prior art, a method for constructing a deep shaft using a vertical shield machine according to the present invention has the following features as shown in the drawings: a) A step in which a sealed, muddy water pressurizing type vertical shield machine 1 is placed facing downward at a predetermined position on the ground, a reaction force device 2 of the vertical shield machine 1 is installed, and excavation is performed vertically downward (Figs. 1A and B). ) and b) the shaft bottom part 6 where the shaft 5 has been excavated to a predetermined depth.
Steps of enlarging the diameter of the cutter head 3 at the position of and moving the cutter head 3 vertically downward with a predetermined stroke to perform bottom-expanding excavation (FIG. 1C); and c) installing a steel frame or reinforcing bar in the bottom-expanding portion 9 The shaft bottom plate 6 is constructed by placing concrete and pouring concrete.

[0005] In addition, the vertical shield machine 1 applied to the present invention has a cutter head 3 of a spoke type with center support, and is configured to be expandable and contractible in the radial direction, and furthermore, is capable of advancing and retreating with a predetermined stroke in the excavation direction. It is characterized by its configuration.

[0006]

[Operation] Initially, the vertical shield machine 1 excavates vertically downward by applying an excavation reaction force to the reaction force device 2. Thereafter, the excavation is carried out using the propulsive reaction force generated by the circumferential friction between the shield segment 8 and the ground. Regarding groundwater and groundwater pressure, the stability of the face at the tip of the excavation is ensured by controlling the mud water pressure of the vertical shield machine 1, which is a closed type and pressurizes mud water. In addition, water is stopped at the rear of the excavated portion by the shield segment 8 and the main lining constructed inside the shield segment 8.

[0007] The cutter head 3 has its arms 3b, 3
c (spokes) expand and contract in the radial direction, reducing or expanding the diameter from a minimum of about 3 m to a maximum of about 6 m. Then, by moving the center shaft (rotating shaft) 4 back and forth in the excavation direction, the bottom is expanded to a depth of 2 to 3 m (FIG. 1C). After the bottom expansion is completed, the diameter of the cutter head 3 is reduced so that the diver can enter the face and move the cutter head 3 into the shaft 5.
Collect inside. Alternatively, the cutter head 3 can be connected to the shaft bottom plate 6.
It is also used as a reinforcing material (steel frame).

[0008] As the concrete in the shaft bottom plate 6 hardens and the water is stopped from the tip of the outer frame 1a of the vertical shield machine 1, there is no fear of groundwater intrusion, and the groundwater pressure is absorbed by the shaft bottom plate 6 and its water is stopped. A structure is created in which the load is transmitted to the ground as a shield lining.

[0009]

Embodiments Next, illustrated embodiments of the present invention will be described. FIG. 1A shows a stage in which a vertical shield machine 1 is placed facing downward at a predetermined position on the ground, a reaction force device 2 is provided thereon, and preparations are made to start digging vertically downward. The applied vertical shield machine 1 is of a closed type and pressurizes muddy water. Moreover, the cutter head 3 has arms (spokes) 1b and 1c arranged in the radial direction from 0 to
The cutter head 3 can be expanded and contracted by about 1.5 m, and the minimum diameter of the cutter head 3 can be reduced to about 3 m, and the maximum diameter can be expanded to about 6 m. In FIGS. 2A and 2B, 1d is a movable bit attached to arms 1b and 1c, and 1e is a fixed bit. The central shaft 4 of the cutter head 3 is configured to be able to advance and retreat in the excavation direction with a stroke of about 0 to 2.5 m. Reaction force device 2
is configured to take a reaction force to the ground by underground anchors 7, 7.

FIG. 1B shows a stage in which the construction of the shaft 5 has progressed to a certain extent by the vertical shield machine 1 digging vertically downward, and FIG. 1C shows the stage where the shaft 5 has been constructed to a target depth of 50 m to 100 m below the ground surface. This shows the stage in which the construction of the shaft has progressed and the bottom has been expanded at the bottom of the shaft. This bottom-expanding excavation is a preparation for constructing the shaft bottom plate 6, and the shield cutter 3 is expanded to a diameter of about 6 m, and the
Dig 3m. In the above-mentioned bottom-expanding excavation, the amount of muddy water in the excavation chamber (bottom-expanding section) 9 naturally increases, but the muddy water pressure control mechanism of the shield machine 1 maintains a constant water pressure (5~ 10kg/cm2
) to hold. When the above-mentioned bottom-expanding excavation has progressed to a predetermined stroke, flocculating material is put into the muddy water in the excavation chamber 9, stirred well to cause muddy water separation, and fresh water replacement is performed. This ensures good visibility for divers entering the face. After the above fresh water replacement is completed, the manholes of the first bulkhead (pressure wall) 1b and second bulkhead (pressure wall) 1c of the vertical shield machine 1 are opened and closed, and the diving chamber 1d partitioned between the two is opened and closed. Water or drainage control and water pressure control allow the diver to enter the face (excavation chamber 9). Before the diver enters, the cutter head 3 is previously reduced in diameter to its minimum diameter and retreated (raised) to a position as close to the first bulkhead 1b as possible. Then, the cutter head 3 is recovered by a diver disassembling the cutter head 3 and bringing the disassembled parts into the diving chamber 1d. Alternatively, a method may be implemented in which the cutter head 3 is retreated to the diving chamber 1d through the manhole of the first bulkhead 1b while remaining in the minimum diameter reduced state.

After recovering the cutter head 3 as described above, the reinforcing bars and steel frames are brought into the excavation chamber 9 where the bottom has been expanded, and they are assembled to form the shaft bottom plate 6.
reinforcement will be installed. Note that instead of bringing in a steel frame, the cutter head 3 can be used as a substitute for the steel frame. After installing the reinforcement as described above, the diver returns from the excavation chamber 9 into the shaft 5. and,
The shaft bottom plate 6 is constructed by placing underwater concrete in the excavation chamber 9 by replacing it with muddy water (FIG. 1D). In addition, as a means of completely water-stopping the shaft bottom plate 6, the shield skin plate 1f that constitutes the outer frame 1a of the vertical shield machine 1 is configured to be able to advance and retreat by about 30 to 100 cm, and is used as a water-stopping plate. . As shown in FIG. 3, after pouring underwater concrete into the excavation chamber 9, while the concrete is not yet hardened, the shield skin plate 1f is advanced to penetrate sufficiently deeply into the concrete and become fixed. be.

After the concrete of the shaft bottom 6 is completely hardened and completed as described above, the remaining mud water is removed from the excavation chamber 9, and the skin plate of the vertical shield machine 1 is molded into the outer frame 1a. A main lining will be used as the frame. In this case, the lower bottom part of the shield segment 8 constructed on the upper part is temporarily supported by a hollow steel pipe and concrete support by operating a propulsion jack. The main lining is constructed with the supporting material involved.

[0013] In this way, construction of the deep shaft 5 approximately 100 m below the ground surface is completed. After that, the pressure inside the first and second bulkheads 1b and 1c is reduced, and the cutter head 3
It is possible to dismantle and recover the unrecovered main equipment of the vertical shield machine 1, including the equipment, and to reuse them.

[0014]

[Effects achieved by the present invention] According to the method for constructing a deep shaft using a vertical shield machine according to the present invention, it is possible to provide an access shaft essential for the development of a deep unused underground space. Moreover, such access shafts can be constructed efficiently, economically, and safely.

[Brief explanation of the drawing]

FIG. 1 A to D are important process diagrams of the shaft construction method of the present invention.

FIGS. 2A and 2B are bottom views showing the cutter head of the vertical shield machine in its diameter-reduced and diameter-expanded states;

FIG. 3 is a cross-sectional view showing a water stop structure of the bottom of the shaft.

[Explanation of symbols]

1 Vertical shield machine 2 Reaction force device 5 Vertical shaft 6　Bottom part of shaft 3 Cutter head 9 Expanded bottom excavation part

Claims (2)

[Claims] Claim 1: a) A step of arranging a closed type muddy water pressurizing vertical shield machine facing downward at a predetermined position on the ground, and installing a reaction force device for the shield machine to excavate vertically downward; b) ) enlarging the diameter of a cutter head at a position in the bottom of the shaft where the shaft has been excavated to a predetermined depth, and making the cutter head excavate vertically downward with a predetermined stroke to perform bottom-expanding excavation; A method for constructing a deep shaft using a vertical shield machine, which comprises the following steps: installing a steel frame or reinforcing bars, and pouring concrete to construct a shaft bottom. [Claim 2] The vertical shield machine is characterized in that its cutter head is a center-supported spoke type and is configured to be expandable and contractible in the radial direction, and furthermore, is configured to move forward and backward within a predetermined stroke in the excavation direction. A method for constructing a deep shaft using a vertical shield machine according to claim 1.