JPH08135396A - Base rock holding method of crain guarder - Google Patents

Abstract

PURPOSE: To minimize the base rock excavating amount when crain guarders to guard a ceiling crain are set at both sides of the ceiling of an underground structure, and to make both a timbering work and a high place work unnecessary. CONSTITUTION: In a structure in which crain guarders 14 are set at both ends of a ceiling 10 and vertical walls 18 at the lower side, in the main body 20 of an underground power plant obtained by excavating a base rock E by a tunnel construction method, along its longitudinal direction, and both ends of a ceiling crain 26 are set on the crain guarders 14 runnable, the crain guarders 14 are set to the setting surfaces 10a at both sides of the base of the ceiling 10 excavated preceding. After the crain guarders 14 are fixed to the base rock E by plural fixing anchors 16 hit in to the base rock K by penetrating the sides of the crain guarders 14, the inner side partitioned by both crain guarders 14 is excavated to the lower side, so as to form a vertical wall 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supporting a bedrock of a crane girder, and more specifically, for guiding an overhead crane to both sides of a ceiling part in an underground structure such as an underground powerhouse obtained by excavating the bedrock by a tunnel method. For supporting the crane girder for

[0002]

2. Description of the Related Art As a construction method for constructing an underground structure such as an underground hydroelectric power plant, there is a tunnel construction method for constructing various concrete structures inside a tunnel obtained by excavating rock. In particular, in underground hydropower stations, crane girders are installed on both sides of the ceiling part, and an overhead crane whose both ends are guided by this crane girder is arranged so that it can travel.
It is common to carry a generator or other large-scale machine for power generation.

FIG. 1 shows a conventional geohydropower station, which has a width W of 24 m and a height H of 19.4 m.
After excavating the bedrock E so that the ceiling portion 1a has an arch-shaped cross section, a main body portion 1 made of a vertically long tunnel that is long in the direction orthogonal to the paper surface is obtained, and then sprayed with concrete 2 on the inner surface thereof.
The crane posts 3 are constructed on both sides of the inner surface of the vertical wall portion 1b at predetermined intervals in the direction orthogonal to the paper surface, and the crane girders 4 are continuously installed on top of the crane posts 3 and then the crane girders are installed. Both ends of the overhead crane 5 are installed on the guide 4, and the guide is movably guided thereby. In the figure, reference numeral 6 is a slab concrete, and 7 is a concrete structure constructed inside the main body 1 together with the crane post 3.

[0004]

However, in the above conventional method, when it is desired to secure a sufficient space width,
The inward projecting portion of the crane post 3 becomes a dead space, and therefore, only the projecting amount of the original body 1
Since it is necessary to take a wide range, the amount of rock excavation increases, and there is a drawback that the construction period and construction cost increase significantly.

In addition, after the main body 1 is completed, installation work and removal work of the support work are required to construct the RC crane post 3, and there is also a drawback that workability is poor because it is work at a high place.

The present invention is to solve the above problems, and its object is to minimize the amount of rock excavation when installing crane girders for guiding an overhead crane on both sides of the ceiling of an underground structure. It also provides a rock support method for crane girders that does not require support work and does not require work in high places.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a crane girder along the longitudinal direction on both sides of a ceiling portion of an underground structure obtained by excavating rock mass by a tunnel method. A method of installing both ends of an overhead crane on a crane girder so that the crane can travel, wherein the crane girder is installed on both sides of the base of an arch-shaped ceiling part that was previously excavated, and a plurality of penetrating sides of the crane girder are provided. After fixing the crane girder by driving the fixed anchor of (1) into rock, the inner wall partitioned by the crane girder is excavated downward to form a vertical wall portion (claim 1).

The crane girder may be a concrete structure integrally formed with the arch-shaped ceiling portion (claim 2).

[0009]

According to the construction method of claim 1, in the completed state of the underground structure, the crane girder is installed and fixed on the step portion formed on the upper part of the rock bed constituting the vertical wall portion. The load applied to the bedrock is distributed by the fixed anchor.

By adopting the structure of claim 2, the stability of the crane girder can be enhanced.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. 2 (a) to 2 (c) show a construction procedure of a ground hydropower station according to the first embodiment of the present invention.

First, as shown in (a), the ceiling portion 10 is excavated in an arch shape inside the bedrock E by the tunneling method, and the inner surface of the ceiling portion 10 is covered with the sprayed concrete 12.

Next, the parallelism between the installation surfaces 10a at both bases of the ceiling portion 10 and the horizontality and straightness in the direction orthogonal to the paper surface in the drawing are measured to satisfy the installation standard of the crane girder. Inspect and adjust whether or not
As shown in (b), the crane girders 14 are installed and fixed on both installation surfaces 10a, and then a plurality of fixed anchors 16 are penetrated through the side surfaces of the crane girders 14 at predetermined intervals along the longitudinal direction to the surrounding rock mass E. Drive into the rock and fix it to bedrock E. Each fixed anchor 16 has a function of distributing a vertical load applied to both crane girders 14 and transmitting the vertical load to the bedrock E. In FIGS. 1 (a) and 1 (b), the installation surface 10a is a stepped portion and the lower portion is excavated shallowly, but it is not always necessary to provide the stepped portion at the time of installation.

After the fixed anchor 16 is installed and fixed, the inside divided by the crane girders 14 is (b).
As shown by the broken line in FIG. 1, if the lining with the shotcrete 12 is carried out while excavating downward, the main body portion 20 in which the vertical wall portions 18 are formed on both lower sides of the arched ceiling portion 10 is formed.
Is built. If the bottom slab 22 and another concrete structure 24 are constructed in parallel with this excavation work or after the construction of the main body portion 20 is completed, the underground hydroelectric power plant is completed.

At the time of completion, the overhead crane 26
Both ends of are mounted on the crane girder 14, and these can be used as guides to run in a direction orthogonal to the plane of the drawing.

The crane 26 may be installed immediately after the construction of the crane girder 14 or after the excavation has progressed to some extent. In either case, after the installation, the crane 26 may be installed. It immediately functions as a crane and can be used for loading and unloading of materials for excavation or construction of structures, and then used for transporting generators and other large-scale machines for power generation after the completion of a groundwater hydropower station. It will be.

The stress due to the load of the hoisting material concentrates on the lower part of the installation surface 10a of the crane girder 14, but this part is a solid rock E, and is formed continuously as compared with the conventional crane post. Furthermore, a part of the vertical load is distributed to the side of the bedrock E through the fixed anchors 14, so that sufficient proof stress can be provided.

Further, the dimensions of the underground hydroelectric power station constructed by the above construction method are the same as those of the conventional one shown in FIG.
Is 24 m and the height H is 19.4 m, the construction of the crane post is unnecessary, and the excavation cross section for the amount of protrusion of the post inward is small, so the construction period is 3-4. It has been shortened by a month, and the construction cost has been reduced by several hundred million yen.

FIG. 3 shows a second embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals, and different parts are designated by different reference numerals. The ceiling portion in the figure is constituted by arch concrete 30. The arch concrete 30 is formed in a fan shape from the center O of the radius,
Crane girder portions 32 are integrally formed on both sides of the base portion, and fixed anchors 16 are driven into the ground E through the side surfaces of the crane girder portions 32, and this portion is fixed to the ground E.

Also in this case, the ceiling portion is first excavated and the arch concrete 30 is constructed, and then the inside surrounded by both crane girder portions 32 is excavated to integrate the vertical wall portions 18 at both lower portions of the ceiling portion. The main body 20 is built.

In this embodiment, the crane girder portion 32 is integrally formed on both lower sides of the arch concrete 30, so that the load applied to the crane girder portion 32 is shared by the entire arch concrete, so that the stability can be further enhanced. .

Further, in this embodiment, although it takes a lot of time to construct the arch concrete 30, the arch height of the ceiling portion 10 of the first embodiment is higher than that shown by the broken line in the figure, but it depends on the concrete strength. The arch height can be reduced and the ground excavation amount can be reduced.

[0023]

As described above in detail with reference to the respective embodiments, in the rock support method for the crane girder according to the present invention, the crane girder constitutes the vertical wall portion in the completed state of the underground structure. Since it will be installed and fixed on the step formed at the top of the crane, the load applied to the bedrock through the crane girder will be distributed by the fixed anchors, so it is possible to reduce the number of crane posts and to replace the bedrock that replaces the crane posts. Since it is in an excavated state, the amount of excavated rock can be reduced, the construction period and construction cost can be greatly reduced, and there is the advantage that work at high places is not required and no support work is required. Further in the present invention,
Since the overhead crane can be used even during the excavation of the vertical wall portion, the use of the overhead crane can be further expanded. Further, by adopting the configuration of claim 2 of the present invention, the stability of the crane girder can be further enhanced and sufficient safety can be ensured. Further, there is an advantage that the amount of excavation can be further reduced by reducing the height of the arch on the ceiling.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a completed state of a conventional underground hydropower station.

2 (a) to 2 (c) are cross-sectional views showing a construction procedure of a ground hydropower station according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a completed state of the underground hydroelectric power plant according to the second embodiment of the present invention.

[Explanation of symbols]

 10 Arched Ceiling 10a Installation Surface 14 Crane Girder 16 Fixed Anchor 18 Vertical Wall 20 Main Body 26 Overhead Crane 30 Arch Concrete 32 Crane Girder E Rock

Claims (2)

[Claims] 1. A method of arranging crane girders along the longitudinal direction on both sides of a ceiling portion of an underground structure obtained by excavating rock mass by a tunnel construction method, and installing both ends of the overhead crane on the crane girder so that the crane can travel. The crane girders were installed on both sides of the base of the arched ceiling part that was previously excavated, and a plurality of fixed anchors were pierced through the lateral sides of the crane girders into the rock to fix the crane girders. After that, a vertical wall portion is formed by excavating the inner side partitioned by the crane girder downward, thereby forming a rock support method for the crane girder. 2. The method for supporting a crane girder according to claim 1, wherein the crane girder is a concrete structure integrally formed with the arch-shaped ceiling portion.