JPH04285290A - Method for constructing deep circular vertical shaft - Google Patents

Abstract

PURPOSE:To construct a circular vertical shaft of great depth wherein the thickness of a landslide protection wall and the depth of embedment are reduced, workability is improved, and economy is increased. CONSTITUTION:A vertical shaft is excavated inwater inside a cylindrical landslide protection wall 2 constructed inside the ground 1 and a plurality of flexible tubes 7 are cylindrically arranged inside the vertical shaft. A liquid-setting material 10 is pressed into the tubes 7 and a reinforcing ring 13 is constructed inside the landslide protection wall 2. Bottom concrete 15 is placed inwater and then water is drained from the inside of the vertical shaft.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a deep circular shaft which is affected by groundwater pressure.

0002

BACKGROUND OF THE INVENTION The underground continuous wall construction method is generally used to construct deep circular shafts, and if the excavation is deep, a reinforcing ring is constructed by reverse drilling. Since excavation is carried out by dry-up the excavation side, water pressure acts on the retaining wall, and when excavating deep, the ground becomes hard, so the hydraulic load accounts for most of the load.

0003

[Problems to be solved by the invention] In the conventional construction method, there are many water leaks due to high water pressure, and in order to ensure safety against uplift pressure from below, the retaining wall needs to have a very long embedded part. , getting bigger and bigger. In addition, the thickness of the retaining wall is determined at the bottom where the water pressure is greatest, so the wall thickness at the top becomes unnecessarily large, which is uneconomical.

Furthermore, since the reverse pouring method is generally adopted, the work becomes complicated. The present invention has been proposed in view of the problems of the prior art, and its objectives are to reduce the wall thickness and penetration depth of retaining walls, improve workability, and improve economic efficiency. The object of the present invention is to provide an improved method for constructing a deep circular shaft.

[0005]

[Means for Solving the Problems] In order to achieve the above object, according to the method for constructing a shaft according to the present invention, a cylindrical mountain retaining wall is constructed in the ground, and the shaft is constructed underwater inside the mountain retaining wall. excavated and placed multiple flexible tubes in a cylindrical shape within the same shaft.
A reinforcing ring is constructed inside the retaining wall by press-fitting a liquid hardening material into the tube, and a concrete bottom slab is constructed underwater in the shaft, after which water in the shaft is drained.

[0006]

[Operation] According to the present invention, after constructing a cylindrical mountain retaining wall on the required ground, by underwater excavating the inside of the mountain retaining wall,
The shaft will be excavated with water pressure acting on the inside of the mountain retaining wall, which will offset the groundwater pressure acting on the outside of the mountain retaining wall. Next, a plurality of flexible tubes are arranged in a cylindrical shape in the shaft, and a liquid hardening material is press-fitted into the tubes to expand the tubes, thereby constructing a reinforcing ring that is crimped to the inner wall surface of the retaining wall. This makes it possible to excavate a vertical shaft while applying water pressure to the retaining wall.

[0007] Next, after constructing the bottom concrete submerged in the shaft, the water in the shaft is drained to construct a deep shaft whose watertightness is maintained by the flexible tube constituting the reinforcing ring. It is something.

[0008]

[Embodiment] The present invention will be described below with reference to the illustrated embodiment. As shown in FIGS. 1 and 8, a cylindrical retaining wall 2 is constructed by arranging retaining members in a cylindrical shape on a required ground 1. . (First step) Next, as shown in FIG. 2, the water level 3 inside the cylindrical retaining wall 2 is kept constant, and the excavator 4 is used to dig the vertical shaft while applying a predetermined water pressure to the inner surface of the retaining wall 2. excavate underwater. (Second process) In the figure, 5 is a crane and 6 is a top reinforcing ring.

Next, as shown in FIG. 3, a cylindrical body consisting of a flexible tube 7 having airtightness and pressure resistance that is continuous in the depth direction is set along the cylindrical retaining wall 2. (Third Step) In the figure, 8 is an upper reinforcing ring for suspending the flexible tube 7, and 9 is a lower reinforcing ring for retaining the shape of the flexible tube 7. Next, as shown in FIGS. 4 and 9, a liquid hardening material 10 such as cement mortar is press-fitted into the flexible tube 7, and the flexible tube 7 is expanded and hardened. (Fourth step) An injection pipe 11 and an exhaust pipe 12 are connected to each of the flexible tubes 7 as shown in FIG. 11, and the liquid hardening material 10 is sequentially press-fitted from the lower flexible tube 7. Note that after the liquid curable material 10 in the lower flexible tube 7 is cured, the liquid curable material 10 is injected into the adjacent upper flexible tube 7. In addition, the upper and lower flexible tubes 7
If there is sufficient connection strength, the liquid hardening material 10 may be injected into a plurality of flexible tubes 7 at the same time. Furthermore, in order to reduce the load on the flexible tube connection part, air may be sealed in the upper flexible tube 7 to utilize buoyancy. Fibers may also be incorporated to improve the strength properties of the liquid curable material.

After the reinforcing ring 13 expanded by injecting the liquid hardening material 10 is thus constructed inside the retaining wall 2, the reinforcing bar cage 14 of the bottom plate of the shaft is inserted into the shaft as shown in FIG. (Fifth step) Next, as shown in FIG. 6, a bottom slab concrete 15 is placed in the shaft via a tremie pipe 16. (Sixth step) As the concrete 15, high fluidity concrete that does not require compaction is used.

When the bottom slab concrete 15 reaches the required strength, the water in the shaft is drained as shown in FIGS. 7 and 10, and finishing concrete 17 is placed on the inner surface of the shaft as necessary to complete the circular shaft. Complete. (7th step, final step)

0012

According to the present invention, when excavating a cylindrical mountain retaining wall constructed in the ground, water pressure is applied to the inside of the mountain retaining wall to offset the groundwater pressure acting on the outside of the mountain retaining wall. Since it is safe against piping and heaving during construction, the length of the retaining wall to be embedded can be shortened, reducing the need for reinforcement during temporary construction. Additionally, excavation work can be carried out safely because there are no struts.

[0013] Also, inside the mountain retaining wall, underwater,
By injecting a liquid hardening material into a plurality of flexible tubes connected in a cylindrical shape and constructing a reinforcing ring by hardening the same material, the wall thickness of the retaining wall can be reduced. A highly watertight vertical shaft is constructed by constructing a reinforcing ring in which flexible tubes are continuously arranged inside the retaining wall.

Furthermore, according to the present invention, groundwater is not pumped up from the surrounding ground during construction, so ground subsidence and fluctuations in the groundwater level are suppressed. Furthermore, according to the present invention, complicated form work is not necessary, and workability is improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the first step of an embodiment of the method for constructing a deep circular shaft according to the present invention.

FIG. 2 is a longitudinal sectional view showing the second step of the method of the invention.

FIG. 3 is a longitudinal sectional view showing the third step of the method of the invention.

FIG. 4 is a longitudinal sectional view showing the fourth step of the method of the present invention.

FIG. 5 is a longitudinal sectional view showing the fifth step of the method of the present invention.

FIG. 6 is a longitudinal sectional view showing the sixth step of the method of the present invention.

FIG. 7 is a longitudinal cross-sectional view showing the final step of the method of the invention.

FIG. 8 is a cross-sectional plan view of FIG. 1;

FIG. 9 is a cross-sectional plan view of FIG. 4;

FIG. 10 is a cross-sectional plan view of FIG. 7;

FIG. 11 is a partial longitudinal sectional view of a series of flexible tubes.

[Explanation of symbols]

1. Ground 2 Cylindrical mountain retaining wall 4 Excavator 7 Flexible tube 11 Injection tube 12 Exhaust pipe 13 Reinforcement ring 15 Bottom slab concrete

Claims (1)

[Claims] [Claim 1] A cylindrical mountain retaining wall is constructed in the ground, a vertical shaft is excavated underwater inside the mountain retaining wall, a plurality of flexible tubes are arranged in a cylindrical shape within the vertical shaft, and a plurality of flexible tubes are arranged in a cylindrical shape within the vertical shaft. A deep circular shaft is characterized in that a reinforcing ring is constructed inside the retaining wall by press-fitting a liquid hardening material into the shaft, and a bottom slab concrete is constructed underwater in the shaft, and then water in the shaft is drained. Construction method.