JPH0321789A - Sharp bending shield method - Google Patents

Abstract

PURPOSE:To reduce the size of a vertical shaft for converting direction, to prevent a collapse of a pithhead for drawing-out, and to reduce the time from converting the direction to a reexcavation, by converting the direction of a shield machine whose shield tail is removed, in the vertical shaft for converting direction. CONSTITUTION:A shield machine A is advanced to the midway of a vertical shaft B for converting direction through a pithhead D for drawing-out. A shield tail (b) is removed at the pithhead D and left in the ground, and after that, a shield machine A' is converted its direction in the vertical shaft B. Then, a pressure-holding wall F and a pithhead G for reexcavation are arranged in the vertical shaft B, and after excavating temporarily by the shield machine A', preferably, the other shield tail (c) is connected, and the reexcavation is started by a shield machine A''. In this case, the removal and the connection of the shield tails (b) and (c) are carried out by a cutting and a welding, but in the other way, removing and connecting means provided at the tails (b) and (c) beforehand may be used, or the both methods may be used concurrently.

Description

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

The present invention relates to a shield construction method in which a tunnel is excavated and constructed using the propulsion of a shield machine, and more particularly to a shield construction method in which tunnels are excavated along sharp curves.

[Conventional technology]

Conventionally, in the steep curve shield construction method in which excavation is carried out along a sharp curve with a radius of 15 m or less, a vertical shaft for turning is excavated at the required position, and the shield machine is turned in the shaft and the necessary processing work is carried out. After the excavation was carried out, the excavation was carried out again. To briefly explain this with reference to FIGS. 12 and 13, Shield 4! 11 is drawn out through the extraction shaft 4 of the retaining wall 3 into the direction change vertical shaft 2 which has been excavated in advance. The shielding machine 1 is turned around on the pedestal 5, the front cutter bit 1' is directed to the new excavation direction, and the bearing wall 6 and temporary shoring 7 are installed (the 13th
Figure), the tunnel will be re-excavated from the pit entrance 8 according to the customary method.

[The invention is trying to solve the problem! ] The above-mentioned direction change vertical shaft 2 includes a bearing wall 6 and a temporary support 7 in addition to an area 9 necessary for changing the direction of the shield machine i itself.
It is recognized that it is necessary to use a shield with a diameter approximately twice as long as the length of the AT, including the area where the AT is attached and the extra space for various types of work. It has become extremely difficult to excavate large-diameter shafts when considering the impact on nearby residents and the buried objects, etc., in construction work in the vicinity of existing buried objects or structures. ing. In addition, in the above, the shield at is connected to the vertical shaft 2 for direction change.
When the shield Ill is pulled out, the surrounding area of the extraction pit 4 may collapse, and the tunnel opening must be thoroughly cleaned after being pulled out. It takes a surprising amount of time from changing the direction of the shield Ill to starting digging again. Ta. The main object of the present invention is to make it possible to easily change the direction of a shield machine even if the vertical shaft for turning is small, and another object is to prevent the collapse of the extraction tunnel entrance and to handle the tunnel opening after extraction. make it easy to implement,
The purpose of this is to make it possible to change the direction of the shield machine and start digging again in a short period of time.

[Means to solve the problem]

The principles of the present invention proposed to achieve the above objectives are as follows. The steep curve shield construction method of the present invention relates to a steep curve shield construction method in which the direction of the shield machine is changed within the direction change shaft, and then the shield machine excavates again.・First, the shield aA that has been dug is entered halfway into the direction change vertical shaft B through the extraction shaft D,
Separate the shield tail part b of it at the extraction pit D and insert it into the ground. Place it. Next, the shield machine A' with the shield tail part b cut off
The direction is changed in the above-mentioned direction change shaft B. Then, a separately manufactured shield tail part C is connected to the rear end of the shield front half of the shield liA', and a shield aA' having a shield tail part like the shield machine A is obtained. After that, the shield aA# starts digging again. In the above, if the separately manufactured shield tail C is connected to the shield lIA' from which the shield tail part b has been cut off, after the above direction change and the shield lIA' is temporarily dug, the result will be as shown below. The vertical shaft B for changing direction can be made even smaller. Further, by separating and connecting the shield tail portion b by cutting and welding, the work can be made simple and strong. However, the shield tail part b of the shield mA is made to be freely accessible and detachable using a required approach and detachment means, and the additional shield tail part C
It is also convenient to provide a necessary contact/separation means in advance and to separate and connect these shield tail portions b and C using the contact/separation means. Incidentally, the separation and connection of the shield tail part b can also be carried out by combining the above-described cutting and welding with the connecting and separating means provided in advance on the shield tail part b and the additional shield tail part C.

[Effect]

As mentioned above, since the shield Ia 8' from which the shield tail part b has been separated is changed direction in the direction change shaft B,
The vertical shaft B for changing the direction needs to be much smaller than when changing the direction of a shield machine that is still equipped with the shield tail part B. However, by connecting a separately manufactured shield tail portion C to the shield vlA', it is possible to re-excavate in the same manner as before.

【Example】

In the following, a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6. A is a shield machine, and when the shield machine A, which has been excavating using a conventional excavation method, reaches a turning shaft B with a rectangular cross section, it opens a withdrawal shaft D in a retaining wall C. Next, the shield machine A is moved halfway into the direction change shaft B through the extraction shaft D, that is, at least the front half of the shield (made of steel M) that surrounds the machine room a is inserted into the direction change shaft B. The shield tail part b, which does not have a machine such as a shield jack installed inside, is pulled out to the relevant position located rearward from the extraction shaft D (Fig. 1.2). After caulking between the earth retaining wall C and the shield tail part b by known means, the shield of the shield iA is cut by melting along the inner wall surface of the direction change shaft B, in other words, along the inner surface of the earth retaining wall C. Cut it using an appropriate method and separate the shield tail part b from the front half of the shield. The separated shield tail part b remains as it is on the ground ψ
This prevents the collapse of the earth and sand around the extraction tunnel entrance D, and also eliminates the need to deal with tail voids formed between the existing segment and the ground. In other words, the above-mentioned caulking is sufficient for wellhead treatment, and the amount of backfill injection can be reduced accordingly.
This contributes to reducing the amount of auxiliary processing in the reaching section. Next, the shield machine A' with the shield tail part b cut off is advanced to the center of the direction change shaft B, and the direction is changed according to the customary method on the mount E (Fig. 3). Furthermore, a bearing wall F is installed at a predetermined position within the direction change shaft B, and a re-excavation tunnel entrance G is installed on the re-excavation direction side. After that, use the narrow segments as temporary support and attach the shield aA' to the additional shield tape described later. Temporarily advance to a place where you can secure the space necessary for the work of adding the part, and use the shield ImA' to hold the ground, and at that position, shield tail part C for the addition, which is prepared separately. Shield 4L! It is integrally welded and connected to the rear end of the front half of the shield A', thereby obtaining a shield ellA' that is substantially the same as the shield machine A (Fig. 5). The supplementary shield tail part C is made separately from a steel cylinder and is substantially the same as the shield tail part B, which is placed underground. Therefore, temporary shoring H is installed on the bearing wall F, and the shield machine A# is pushed in the usual way, that is, with jack thrust, to resume excavation. 7 to 11 show a second embodiment of the present invention. This second embodiment differs from the first embodiment in that the direction change shaft B' has a circular cross section, and that the side of the bearing wall F' that contacts the inner wall surface of the shaft B' is curved. Other than the difference from the embodiment, there are no other differences from the first embodiment, and FIGS. 7 to 11 correspond to FIGS. 2 to 6, respectively. Therefore, to avoid redundancy, the same parts will be given the same reference numerals and their explanations will be omitted. In this second embodiment, the shield I! The shield tail part b of A is
When cut in a straight line as in the example, the vertical shaft for changing direction B
Although there is a crescent-shaped protrusion within ′, this protrusion does not pose any particular problem. However, if necessary, by cutting it in a curved state along the inner wall surface of the shaft B', that is, along the arcuate dotted line l in FIG. This can be done so that it does not stick out. In the figure, J is the shield machine cradle, K is the existing segment,
L indicates the tail void between segment K and the ground, and this tail void is backfilled as appropriate during excavation work. Note that the means for cutting/separating and connecting the shield tail part b of the shield IIA is not limited to cutting and welding in the first and second embodiments; It is possible to freely connect and disconnect using a required connecting and disconnecting means, and the additional shield tail part is also provided with a required connecting and disconnecting means in advance, and the connecting and disconnecting means is used to perform disconnection and connection, and furthermore, this connecting and disconnecting means It is also possible to use the above-mentioned cutting and welding together.

【Effect of the invention】

As is clear from the above description, the steep bend shield construction method of the present invention is recognized to have the following effects. ■ The direction of the shield machine with the shield tail section separated is changed within the direction change shaft, so the direction change shaft is much smaller than when changing the direction of the shield machine with the shield tail section still attached. That's enough. Of course, there is no need to go to the front face of the shield machine and perform preliminary excavation by hand. ■． In relatively narrow places such as under narrow roads or in close proximity to existing buried objects or structures, it is possible to change the direction as desired without worrying too much about the impact on neighboring residents or the buried objects, etc. It is convenient for excavating a vertical shaft. ■ After changing the direction of the shield machine that is not equipped with the above-mentioned shield tail part, by connecting the separately manufactured shield tail part to it, it is possible to immediately start digging again in the same way as before. ■ Also, the shield tail part is separated at the extraction tunnel entrance and placed underground, and
This prevents the collapse of earth and sand on one side and simplifies the treatment of tail voids. In other words, as a wellhead treatment, it is sufficient to caulk the relatively narrow gap between the detention shield tail and the extraction wellhead, and the amount of backfill injection can be reduced accordingly. ■ The construction area for auxiliary construction methods such as strengthening other mountains upon arrival can be reduced. ■ If the shield machine from which the shield tail section has been separated is temporarily moved forward after changing the direction described above, the work area for connecting the separately manufactured shield tail section can be further expanded, and therefore, it can also be used to The vertical shaft for turning can be made smaller by the corresponding amount. ■ The above-mentioned separation and connection of the shield tail part can be done by cutting and welding, or by using the necessary connecting/disconnecting means provided on the shield tail part of the shield machine and the shield tail part for addition.
Furthermore, by using these methods together, it can be done easily and firmly.

[Brief explanation of drawings]

Drawings 1 to 6 show a first embodiment of the present invention, in which Fig. 1 is a cross-sectional view of the shield machine having entered halfway into the direction change shaft, and Fig. 2 is a plan view of the same. , Figure 3 is a plan view showing the shield machine changing direction with the shield tail section separated, Figure 4 is a plan view with the bearing wall installed, and Figure 5 is the separately made shield tail section connected. FIG. 6 is a plan view of the state in which re-mil& has been started, FIGS. 7 to 11 show the second embodiment, and FIG. Figure 8 is a cross-sectional view showing the state where the shield machine has entered halfway, Figure 8 is a plan view showing the direction change state of the shield machine with the shield tail section separated, Figure 9V
! J is a plan view with the bearing wall installed, and Figure 10 is a plan view of the bear with a separately manufactured shield tail connected. Figure 11 is a plan view of the state in which re-excavation has started, Figures 12 and 13 are for explaining the conventionally known shield construction method, and Figure 12 is a diagram of the state in which the shield machine has entered the diversion shaft. The sectional view and FIG. 13 are plan views of the shield machine in a state where it is about to change direction and start digging again.

Claims (1)

[Scope of Claims] 1. In the sharp turn shield construction method, in which the direction of the shield machine is changed in the direction change shaft, and then the shield machine excavates again, the shield machine that has been excavated is moved into the direction change shaft. The shield machine is entered halfway through the extraction shaft, and its shield tail is cut off at the extraction shaft and kept underground, and the shield machine with its shield tail cut off is turned in the direction change shaft, and then ,
A sharp turn shield construction method characterized by connecting a separately manufactured shield tail part to the shield machine and starting re-excavation. 2. A claim characterized in that the shield machine from which the shield tail part has been separated is temporarily excavated after the above direction change, and then the separately manufactured shield tail part is connected to start excavation again. The steep curve shield construction method described in Section 1. 3. The steep turn shield construction method according to claim 1 or 2, wherein the shield tail portion is separated and connected by cutting and welding. 4. The shield tail part of the shield machine can be freely connected and detached using a required connection/detachment means, and the additional shield tail part is also provided with the required connection/detachment means in advance, and these two shield tail parts can be disconnected and connected. 3. The steep curve shield construction method according to claim 1 or 2, wherein: 5. According to claim 1 or 2, the separation and connection of the shield tail portion is performed by cutting and welding in combination with a connecting/separating means provided in advance on the shield tail portion and the supplementary shield tail portion. Sharp curve shield construction method.