JPH0223671Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to an underground passage using a pipe beam that is constructed under an existing railway track or road by the pipe beam construction method.

[Prior art]

Conventionally, in the pipe beam construction method, steel pipes have been used only as temporary materials, and when used as permanent construction materials, they are exposed to live loads from trains for several decades, so they suffer from fatigue, corrosion, etc. There was a problem.

Figures 1 and 2 show the structure of an underground passage 7' using the conventional pipe beam construction method.
After the female joint 12 is attached to the outer surface of the steel pipe 4 in a factory or the like, it is pushed through the steel pipe at the site, earth and sand from the joint is removed, and a hardening material such as mortar is injected.

The construction procedure in this case is as follows with reference to the same figure.

Installation of pillars 6 and beams 5 Pushing in steel pipes 4 Injection of mortar into joints 12 Excavation of earth and sand 3 under steel pipes 4 Reinforcement for underground passage 7' section (ceiling, walls) Placing concrete 8 in the same section Dump concrete 10 Casting Removal of struts 6 and beams 5 Completion of underground passage 7' However, due to constraints on joint strength, the clearance between the male and female joints is relatively narrow in these joints 12, so the degree of mortar filling on site is not perfect.
In addition, due to repeated loads caused by trains, etc., the mortar 14
Problems such as the tendency for cracks to occur in the joints and the problems with the fatigue strength of the joints are obstacles to making them into permanent structures. Therefore, in terms of structural design, the steel pipe 4 cannot be treated as a strength member, and the thickness of the ceiling of the underground passage 7' becomes large, and the amount of excavated earth increases accordingly. Furthermore, in the conventional type, if the degree of mortar filling was low, cracks would occur in the mortar 14, resulting in a decrease in water-stopping properties and a risk of rainwater etc. leaking under the beam.

[Purpose of invention]

This idea was developed to solve the problems in the conventional technology as mentioned above.It has a structure in which steel pipes as pipe beams can be used as strength members for underground passages, significantly reducing construction costs, and improving the We are trying to make effective use of space.

[Structure of the idea]

This idea involves press-fitting steel pipes into the ground in a continuous, almost horizontal manner, connecting adjacent steel pipes with joints, and constructing pipe beams in the excavated space under the steel pipes. A dowel is provided on the outer peripheral surface of the lower part of the steel pipe, and the steel pipe and the concrete of the underground passage ceiling are integrated into a composite structure.

As a dowel, there is a stud method in which studs are directly welded to the outer circumferential surface of the steel pipe, or a reinforcing bar insertion method in which a through hole is provided in the steel pipe and reinforcing bars are inserted to connect the concrete filled inside the steel pipe and the concrete on the ceiling of the underground passage. It is possible to use Due to these dowels, the steel pipe as a pipe beam and the concrete of the underpass ceiling work as a composite structure, and the steel pipe also becomes a strength member of the underpass ceiling.

〔Example〕

FIGS. 3 and 4 show examples of this invention, in which 1 is a railroad track, 2 is gravel on the roadbed, and 3 is earth and sand.

Supports 6 and beams 5 are installed at positions corresponding to the entrance and exit of the underground passage 7, and the horizontally press-fitted steel pipes 4 are supported by the beams 5 and connected to each other by male and female joints 12 on the sides. It supports the load from above. In this state, an underground passage 7 is constructed in the excavated part below the steel pipe 4, and the concrete 8 on the ceiling of the steel pipe 4 and the underground passage 7 is connected by the dowel 13 welded to the lower outer peripheral surface of the steel pipe 4.
are integrated into a composite structure. Note that the pillars 6 and the beams 5 can be removed after the underground passage 7 is constructed.

FIG. 5 shows details of the steel pipe 4, in which a plurality of studs are welded to the lower outer peripheral surface of the steel pipe 4 as dowels 13. Figure 6 shows the case of the reinforcing bar insertion method, where a hole is made in the steel pipe 4 and the dowel 13'
A reinforcing bar with a hook is inserted. Note that the drilling of the steel pipe 4 is performed at a factory or on site.

The construction procedure is as follows.

Installation of struts 6 and beams 5 Pushing in steel pipes 4 Injecting mortar 14 into joints 12 Excavation of earth and sand 3 under steel pipes 4 Attaching dowels 13 to steel pipes 4 Reinforcement in underpass 7 Place concrete 8 in the same parts Supports 6 and removal of beam 5 Underpass 7 completed [Effects of the invention] This invention has the above-mentioned configuration, and since the steel pipe as a pipe beam and the concrete of the underpass ceiling are integrated and work as a composite structure, the ceiling thickness D of the underpass can be reduced. Can be made thinner. Furthermore, if the amount of excavation is the same, the underground passage space H can be increased. Steel pipes serve as a strength component for underground passages, and unlike conventional structures, there is no need to separate them from the ceiling and place concrete in between, so construction materials can be saved, the amount of excavated soil can be reduced, and construction costs can be reduced. Ru.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view taken in a direction perpendicular to the tunnel in the conventional example, Fig. 2 is a sectional view thereof, Fig. 3 is a longitudinal sectional view taken in a direction perpendicular to the tunnel in this invention, and Fig. 4 is a sectional view thereof. FIGS. 5 and 6 are sectional views showing details of steel pipe sections in different embodiments, respectively. 1...Railway, 2...Gravel, 3...Embankment, 4...
Steel pipe, 5... Beam, 6... Support, 7, 7'... Underpass, 8... Concrete, 9... Rebar, 10...
Waste concrete, 11...road, 12...joint,
13,13'... Jibel, 14... Mortar.

Claims (1)

[Scope of utility model registration request] In an underground passage using a pipe beam, steel pipes are continuously pressed into the ground almost horizontally, adjacent steel pipes are connected by joints, and the pipe beam is constructed in the excavated space under the steel pipes. An underground passage using a pipe beam characterized by having a dowel on the outer peripheral surface and a composite structure by integrating the steel pipe and the concrete of the underground passage ceiling.