JPS63268900A - Shield for method of cast-in-place lining construction - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention eliminates steps such as primary lining, secondary lining, and backfilling in conventional shield construction methods.

This invention relates to a shield for the cast-in-place lining method, in which a concrete lining is directly constructed on the ground, where backfilling is injected at the same time as excavation, making construction safer and labor-saving.

(Conventional technology) Conventional shield construction methods generally use segments, and one assembled segment is pushed and excavated, and lining is injected into the gap between the segment and the ground to prevent other mountains from collapsing.
Furthermore, since each work process is divided into parts, such as rolling up concrete and performing secondary lining, the construction period is long and expensive segments are used, resulting in a large construction cost. There is.

In order to improve this work process, the primary lining using segments has been omitted in recent years. The development of a cast-in-place concrete lining method is underway, but since it does not use segments, it is necessary to wait for the cast concrete to set to support the reaction force of excavation, and there is also a method to shield concrete from setting and setting. To do this within the skin plate of.

After excavation, it is necessary to refill the gap between the lining and other piles, which takes a long time, and a shield that can take full advantage of the cast-in-place lining method has not yet emerged. .

(Problems to be solved by the invention) As mentioned above, the shield construction method has progressed to the development and practical application of cast-in-place lining construction methods that do not use segments, but the following problems remain unresolved and urgent development is required. is necessary.

Namely.

fll Traditionally, the shield excavation was assembled backwards. Copper or concrete segments are pressed and excavated, but in the case of cast-in-place lining construction, it takes a considerable amount of time for the concrete to set, so the process has to wait until this time before moving forward, prolonging the process.

(2) In order to place and set concrete within the skin plate of the shield, when the shield is advanced after caking, due to the diameter difference between the excavation outer diameter (ground inner diameter) and the concrete lining outer diameter. Voids are created, which may lead to accidents such as spring water from the ground depending on the stratum, or damage to the ground surface due to collapse of other mountains.

It is an object of the present invention to solve the above problems and provide a shield that can fully utilize the advantages of the cast-in-place lining method.

(Means and effects for solving the problem) This invention has been made in view of the above problems, and in the shield for the cast-in-place lining construction method, the shield is connected to the shield jack and is in close contact with the inner circumferential surface of the skin plate. A sliding annular holder and a concrete pouring pipe installed in the inner formwork.

It is equipped with a concrete casting pipe that penetrates the skin plate, and prevents the propulsion reaction force during shield excavation from being supported by the concrete lining immediately after casting (inner formwork with sufficient strength). In addition, two concrete casting pipes installed at the rear end of the shield skin plate and the inner formwork fill the voids around the lining in synchronization with the excavation, responding to ground pressure and @water pressure. By discharging concrete with discharge pressure, it is safe and efficient by preventing accidents such as spring water from the ground, depression of the ground surface due to collapse, and upheaval of the ground surface due to excessive backfilling. This enables easy digging and advancing work.

(Example) Next, embodiments of the present invention will be described based on the drawings.

Figure 1 is an overall cross-sectional view of the shield for the cast-in-place lining construction method, and shows an annular holder [phase] connected to the shield jack ■ and sliding in close contact with the inner surface of the skin plate ■.
The main components are a concrete casting pipe (■) that penetrates the inside of the skin plate (■) and discharges concrete to the rear of the shield, and a concrete casting pipe (■) installed in the inner formwork (■). The inner formwork (2) has a length of 1 stroke of the shield jack (2) and is divided into a plurality of segments in an arcuate liquid, and one set constitutes a ring.

This is how it is done. An example of the work process for a shield for the cast-in-place lining method will be explained based on Figure 2 (al, fb) and (cl). Figure 2 +a+ shows the inner peripheral surface of the skin plate ■ of the shield body ■ and the inner formwork ■, The state in which unset concrete is being poured from the concrete pouring pipe ■ into the space surrounded by the front end face 0 of the holder [phase] and the fully set lining ■ is shown.The concrete is completely isolated from the ground. Because of this, there is no earth pressure from other mountains, and there is no earth and sand.

A homogeneous lining can be obtained without spring water mixing into the concrete. Once the space is filled with unset concrete, the shield jack begins to extend and excavation begins. The inner formwork is strong enough to handle the reaction force of excavation■
Supported by

Figure 2 (BL shows tail voids that occur during excavation ■, i.e., the skin plate ■ moves forward, so a concrete pouring pipe ■
This indicates a state in which more unset concrete is injected, and the amount of fireflies to be injected is equal to the void created as the shield advances. In addition, if other mountains are particularly prone to collapse and there is spring water, the injection pressure can be adjusted in accordance with the measured Tonosho and spring water pressures to prevent the other mountains from collapsing.

Furthermore, construction can be carried out safely without causing upheaval of the ground surface due to excessive injection amount.

Figure 2 (C1 shows the state in which one stroke of excavation has been completed and the shield jack is reduced 0) For example, if one stroke of excavation is assumed to be about 1,500 dragons, the one stroke of excavation time is usually 500 dragons. (This is a common-sense time required for actual shield construction methods.) When using quick-drying concrete, the elapsed time is about 50 minutes, although the strength of the concrete is insufficient, but approximately It condenses to the extent that it does not flow.In other words, even if the holder [phase] separates from the end face 0 of the newly installed lining ■ with the shrinkage of the shield jack ■, the lining ■ maintains the cast shape. Continuing excavation by installing the inner formwork and repeating the same work as shown in the figure below.In addition, the inner formwork (■) will be removed from the existing lining at the rear after it has completely solidified and used for the new lining.

(Effect of the invention) This invention is constructed as described above in detail.

- It is possible to complete the secondary lining in one work process without using segments for the secondary lining, and material costs can be reduced because excavation can be continued regardless of the setting of poured concrete. This makes it possible to reduce costs and shorten the construction period.

Furthermore, to place concrete during excavation.

When constructing a curved tunnel, it freely adapts to the curvature of the tunnel wall, making construction easier and preventing other mountains from collapsing and raising the ground surface.

Since spring water is reliably prevented, it is possible to implement the cast-in-place lining method, which is highly economical and safe.

[Brief explanation of the drawing]

FIG. 1 is an overall structural diagram of an embodiment of the present invention, FIG. 2 (al, fbl, and c+ are explanatory diagrams of the working steps of the present invention, respectively, and FIG. 3 is a reference example of the prior art. ...Shield body, 2...Shield jack. 3...Skin plate, 4...Inner formwork. 5...Concrete casting pipe (inner formwork). 6...Concrete casting pipe (Skin plate). 10...Holder.

Claims (1)

[Claims] Consists of an annular holder that is connected to a shield jack and slides in close contact with the inner peripheral surface of the skin plate, a concrete casting pipe installed in the inner formwork, and a concrete casting pipe installed through the skin plate. , shield for cast-in-place lining method.