JPH01127796A - Propulsion reaction receiving method in method of cast-in-place shield construction - Google Patents

Abstract

PURPOSE: To increase a friction force of a form and lining concrete by tightening a flush bolt provided in the form after required strength of concrete is obtained. CONSTITUTION: When a form 1 is assembled, a stud 2 is attached to the form 1, and then the form 1 is assembled on a shield face 3. Furthermore, a reinforcing bar 4 is arranged at a predetermined position using the bolt 2 as a spacer to place concrete 5. The stud 2 is loosened when the concrete 5 is still not in a solid state, and the bolt 2 is tightened when required strength is obtained to integrally formed it with the tightening form 1. Consequently, adhesion force and friction force of the form 1 and lining concrete 6 are increased, and propulsion reaction force for a shield jack 7 provided at a tip of the form 1 can be ensured.

Description

[Detailed description of the invention] [Industrial application field]

This invention secures the propulsion reaction force by tightening the embedded bolts installed in the formwork in the lining part where the required strength has been achieved, and the adhesion and friction between the formwork and the lining concrete.

[Conventional technology]

Conventionally, the propulsion reaction force of the cast-in-place shield construction method is transmitted to the concrete lining through the formwork, but the propulsion reaction force of the shield jack is transmitted only by the contact friction force between the formwork and the concrete lining. This is not enough to absorb the force, so it is necessary to insert something like a rubber plate with a high friction coefficient between the formwork and the concrete to increase the frictional force, or to form recesses in the lining. There is also a construction method in which a convex part is provided on the frame so that the two mesh together to provide shear resistance, but the former is still not sufficient to receive the propulsive reaction force, and the latter is complicated to construct. There are drawbacks.

[Problems to be solved by the invention] Even if the propulsion reaction force of the cast-in-place shield construction method is transferred to the concrete through the formwork to absorb the propulsion reaction force, the normal frictional force between the formwork and concrete is not sufficient to absorb the propulsion reaction force. It is an invention that attempts to solve the problem [Means for solving the problem]

Attach embedded bolts to the formwork and pour concrete into the framework. After the concrete develops strength, tighten the embedded bolts to increase the adhesion and frictional force between the formwork and lining concrete and secure the propulsion reaction force against shield jacks. The problem was solved by

[Effect]

After installing the embedded bolts when assembling the formwork, pour concrete, loosen the embedded bolts once when the concrete is young, tighten the embedded bolts after the concrete has achieved the required strength, and integrate the formwork with the formwork and lining concrete. This increases the adhesion force and frictional force of the mold and ensures the propulsion and reaction force against the shield jack installed at the tip of the formwork.

【Example】

After attaching the embedded bolts (2) to the formwork (1) during assembly of the formwork (1), attach the formwork (1) to the shield surface (3).
Assemble and use the embedded bolts (2) as spacers to place reinforcing bars (4) in the designated positions, then pour concrete (5), loosen the embedded bolts (2) by 11 degrees when the material is young, and After the required strength of the concrete (5) is achieved, the embedded bolts (2) are tightened and integrated with the formwork (1) to increase the adhesion between the formwork (1) and the lining concrete (6).
The frictional force is increased to ensure a propulsion reaction force against the shield jack (7) installed at the tip of the formwork (1). Note that (8) indicates a press jack, (9) a shield machine, and (10) a shield machine tail. Next, to describe the configuration of the embedded bolt (2), the hexagonal bolt (11), washer plate (12), formwork skin plate (13) of the formwork (1), cushion material (14) for the hexagonal bolt (11) It consists of an L-shaped anchor (16) with a female thread (15) carved inside, and a cushioning material (
Anchors (16) are installed through the formwork (14), and hexagonal bolts (16) are installed from the outside of the formwork (1) through the washer plates (12).
1) is screwed into the female thread (■5) of the anchor (16).

【effect】

The extension of the formwork can be shortened by increasing the frictional force not only by the adhesion and frictional force between the formwork and concrete lining but also by tightening. When the reinforcing bars and embedded bolts are integrated, the reinforcing bars can be placed accurately in the predetermined positions. Compared to other methods of transmitting the reaction force of the formwork to the lining concrete, this method has the advantage of being easier to work with and requiring no special machinery or equipment.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the entire shield, and FIG. 2 is an enlarged sectional view showing the relationship between the embedded bolt and the formwork.

Claims (1)

[Claims] (1) When the formwork is erected, the embedded bolts are attached and the concrete is placed after the framework is built, and after the concrete has developed its strength, the embedded bolts are tightened to increase the adhesion and frictional force between the formwork and the lining concrete, and the end of the formwork is A method for receiving propulsion reaction force in the cast-in-place shield construction method, which is characterized by securing propulsion reaction force against the installed shield jack.