JPH0633038Y2 - Shield excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a shield excavator.

(Prior art) In the direct lining method, the inner formwork is assembled in the tunnel hole excavated by the shield excavator, and the lining concrete is placed between the inner formwork and the shield tail as well as the existing lining concrete front face. After the installation, by applying propulsion reaction forces to the concrete and the inner formwork, respectively, the lining excavator mounted on the shield excavator is propelled by the concrete jerk and the shield jerk, and the lining excavation is performed. In this method, a reinforcing bar attached to a gable formwork / press ring mounted on the tip of a concrete jack is pressed into the concrete.

(Problems to be solved by the invention) In the direct lining method described above, when the gable formwork is demolded, if the distance between the tip of the shield tail and the gable formwork surface is small, the earth pressure of the rock mass that spreads is propagated. The area crosses the end wall of the cast lining concrete, which causes the disadvantage that the concrete whose strength in the early stage of hardening near the end face is small is directly subjected to the stress generated by earth pressure.

On the other hand, groundwater in the ground is more likely to lead to water leakage as the inflow route is shorter, and therefore in the conventional method, water leakage occurs due to the small distance between the tip of the shield tail and the gable form surface.
The leaked water washes the gable wall of the lining concrete, resulting in a disadvantage for the gable wall's independence.

The present invention has been proposed in view of the above-mentioned problems of the prior art. The purpose of the present invention is to transmit earth pressure from the ground to the lining concrete with a simple structure and to shield groundwater of the ground. The point is to provide a shield excavator that lengthens the inflow route into the tail and promotes self-supporting of the lining concrete gable wall.

(Means for Solving the Problem) In order to achieve the above-mentioned object, a shield excavator according to the present invention has a plurality of thin plates with a gap between each other along a peripheral portion of a tip of a shield tail of the shield excavator. They are arranged side by side and supported in a cantilever manner.

(Operation) According to the present invention, as described above, since a plurality of thin plates are juxtaposed with each other with a gap therebetween along the peripheral portion of the tip of the shield tail of the shield excavator, and supported in a cantilevered manner. , The distance between the tip of the shield tail and the gable wall surface of the cast lining concrete part becomes large, the earth pressure propagation area of the expanded ground does not intersect with the gable wall surface, and the strength of the initial hardening near the gable wall surface. The concrete whose expression is small is not directly subjected to the stress generated by the earth pressure, and the gable wall surface is self-supporting.

Further, the thin plate lengthens the inflow path of groundwater from the ground to the inside of the shield tail, prevents water leakage from the gable wall surface, and the gable wall surface is washed by the water leakage, so that independence is not impaired.

Further, the elastic deformation of the thin plates is increased by the gap formed between the thin plates supported in a cantilever manner along the peripheral edge of the tip of the shield tail, and the thin plates are laid flexibly following the earth pressure and driven against the ground. It is interposed between the lining concrete and the lining concrete and adheres closely to both.

(Embodiment) The present invention will be described below with reference to the illustrated embodiment.

1 and 2, (1) is the shield tail of the shield excavator, (2) is the inner formwork assembled in the tunnel hole excavated by the excavator, and the inner formwork (2) and After placing the lining concrete (3) between the shield tail (1) and the front of the existing lining concrete (not shown), the lining concrete (3) and the inner formwork (2) ), The shield excavator is propelled by the lining concrete jack (4) and the shield jack (5) mounted on the shield excavator.

In the figure, (4a) is a press ring mounted on the tip of the lining concrete jack (4), and (5a) is a spreader mounted on the tip of the shield jack (5).

A large number of thin steel plates (6) along the peripheral edge of the tip of the shield tail (1) are installed in parallel with each other with a minute gap (t) between them. It is cantilevered.

Since the illustrated embodiment is configured as described above, the thin plate (6) supported in a cantilever manner on the peripheral edge of the tip of the shield tail (1) allows the tip of the shield tail (1) and the lining concrete to be covered. The space between the gable wall surface of (3) becomes large, so the earth pressure propagation area of the expanded distribution does not intersect with the gable wall surface, and the lining concrete near the gable wall surface where the strength development in the initial stage of hardening is small is directly Without supporting earth pressure, it does not impair the independence of the gable wall.

The thin plate (6) lengthens the inflow path of groundwater into the shield tail (1), and prevents water leakage from the end wall of the lining concrete (3). As a result, it is possible to prevent the wall surface of the gable from being washed with ground water and impairing the independence. At this time, the gap (t) between the adjacent thin plates (6) is disadvantageous because it shortens the inflow route of groundwater, but this gap (t)
Is extremely small, and the influence of the gap can be ignored for the whole thin plate.

If leakage is observed, the leakage flows between the inside of the thin plate (6) and the lining concrete (3), but if there is a flow velocity, a difference occurs in the water pressure acting on the inside and outside of the thin plate (6), The thin plate (6) is pressed against the side of the lining concrete (3) and closely adheres to the concrete (3) to advantageously prevent leakage of water.
Furthermore, since the mortar and the fine particles of earth and sand etc. are packed in the gap (t) of the thin plate (6), the water blocking effect by the mortar and earth and sand itself is exerted.

Furthermore, since a gap (t) is provided between the adjacent thin plates (6), the elastic deformation of the thin plates (6) becomes large, and it flexibly follows the earth pressure of the natural ground to cover the natural ground. It intervenes between the work concrete (3) and adheres to each other.

If the thin plate (6) is not provided with a gap (t), the thin plate (6) is difficult to fit as a whole even if it partially fits in the ground and the lining concrete (3), and prevents water leakage. Is a disadvantage.

3 to 6 show each embodiment of the mounting structure of the thin plate (6) to the shield tail (1). In the embodiment shown in FIG. 3, a large number of rectangular thin plates (6) are shielded. The tails (1) are juxtaposed along the outer periphery of the tip of the tail (1) with a minute gap (t), and the bases of the respective thin plates (6) are welded (w) to the shield tail (1).

In the embodiment shown in FIG. 4, the base end of the thin plate (6) having a split portion (6c) having a clearance (t) extending in the longitudinal direction at the free end is the tip end of the shield tail (1). It is fixed along the outer peripheral edge of the via a fitting (7).

In the embodiment shown in FIG. 5, the base ends of the elastic thin plates (6) arranged side by side with a gap (t) are welded to the inclined inner peripheral edge of the tip of the shield tail (1). The thin plate
The free end (6b) supported in a cantilever manner from the tip of the shield tail (1) in (6) slides closely along the ground due to its elasticity during the excavation of the shield excavator. Is configured.

In the embodiment shown in FIG. 6, the base ends of the thin plates (6) juxtaposed with each other with a gap (t) are annularly cut along the outer peripheral edge of the tip end of the shield tail (1). The thin plate (6) is fixed to a mounting step (1a) having a step equal to the thickness of the thin plate (6) via a mounting tool (7).

(Effects of the Invention) According to the present invention, as described above, a plurality of thin plates are arranged in parallel with each other along the peripheral edge of the tip of the shield tail of the shield excavator with a gap therebetween, and supported in a cantilevered manner. As a result, by increasing the distance between the tip of the shield tail and the gable wall surface of the lining concrete and lengthening the groundwater inflow route from the natural ground, the lining with a small strength development in the early stage of hardening near the gable wall surface. Prevent concrete from bearing stress generated by earth pressure and prevent water leakage. Therefore, if water leakage is observed on the gable wall surface, if there is a flow velocity in the water leakage flowing between the inside of the thin plate and the lining concrete, the thin plate will move to the lining concrete side due to the water pressure difference acting on the front and back of the thin plate. It is pressure-bonded and has an advantageous effect on preventing water leakage. Furthermore, by packing fine particles of mortar and earth and sand into the gaps between the thin plates, the water-blocking effect is exhibited. It promotes independence.

Further, the elastic deformation of the thin plates increases due to the gap between the thin plates, and the thin plates flexibly deform following the earth pressure, and are interposed between the ground and the concrete and adhere to them.

Further, according to the present invention, when manufacturing, the thin plate is processed, and the shield tail is not directly processed. Therefore, the processing is easy and the thin plate is easily attached to the shield tail, and the workability is improved. Is also economical.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing a tip end portion of a shield tail of an embodiment of a shield excavator according to the present invention, and FIG. 2 is a perspective view showing an attachment portion of a thin plate to a shield tail of the shield excavator, FIGS. FIG. 6 is a perspective view showing another embodiment of the mounting portion for the shield tail of the thin plate. (1) …… shield tail, (2) …… inner formwork, (3) …… lining concrete, (4) …… lining concrete jack, (5) …… shielding jack, (6)… … Thin plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-287396 (JP, A) Actually developed 62-176297 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A shield excavator comprising a plurality of thin plates arranged side by side along a peripheral portion of a tip end of a shield tail of the shield excavator with a gap therebetween and supported in a cantilever manner.