JP2006022503A - Construction method for connecting bifurcated section of shield tunnel, and shield tunnel structure using the construction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance safety in the execution of work and reduce a construction period and construction costs, by enabling a bifurcated section to be surely connected in ground, without using a cut and cover tunneling method etc. concurrently employing an auxiliary construction method, or securing the great length of a merging section; and to enable construction to be surely performed even under high water pressure. <P>SOLUTION: Branch-line tunnels 4 are constituted as three circular tunnels wherein two tunnel structures 10 with a diameter smaller than that of the branch-line tunnel 4 are annexed so that the positional relationship of bringing respective outer peripheral walls of the branch-line tunnels 4 and the two tunnel structures 10 into almost concurrent and partial contact with an outer peripheral wall of a main-line tunnel 2 at the point of merging with the main-line tunnel 2 can be established. After freezing treatment is applied to a section where the outer peripheral wall of the main-line tunnel 2 and the respective outer peripheral walls of the two tunnel structures 10 come into contact with one another, at a point where the maine-line tunnel 2 merges with the three circular tunnels, an opening communication section is opened by removing opposed wall sections of the main-line tunnel 2 and the branch-line tunnel 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shield tunnel branch connection method and a shield tunnel structure using the method, and in particular, without using an open-cut method or the like, without increasing the length of the merged portion, and further improving the ground. It is possible to minimize the auxiliary construction method, connect the branch part in the ground, improve the safety at the time of construction, shorten the construction period and reduce the construction cost, and even work under high water pressure. The present invention relates to a possible shield tunnel junction connection method and a shield tunnel structure by the method.

  For example, the following tunnel merging methods are known as conventional techniques related to tunnel branching connection. In this prior art, tunnels formed by a preceding tunnel structure composed of a plurality of segments and a trailing tunnel structure composed of a large number of small-diameter tunnel structures are joined together. First, a preceding tunnel structure composed of a plurality of segments is constructed in advance, and a subsequent tunnel structure composed of a small-diameter tunnel structure is constructed so as to gradually approach the preceding tunnel structure. When they come into contact with each other, the succeeding tunnel structure is superposed on a part of the non-muscle segment on the outer periphery of the preceding tunnel structure. Thereby, even in the middle of merging, a series / integrated tunnel structure is always constructed, and sufficient strength and water stoppage are ensured. Then, in a state where the overlapped portion by both of the tunnels has a constant strength, the excavation of the small-diameter tunnel structure of the succeeding tunnel structure is stopped, and the inner wall is constituted by the preceding tunnel structure composed of segments. Thereby, since the preceding tunnel structure always constitutes the inner wall, it becomes an auxiliary member when excavating the inside of the tunnel space. And finally, it is set as the structure which completed the excavation of the small diameter tunnel structure of the succeeding tunnel, and was made to converge on the preceding tunnel structure (for example, refer patent document 1).

Further, as a conventional technique related to the construction of a large-section tunnel structure related to the merge of tunnels, for example, the following continuous hole shield method is known. This prior art is followed by excavating the first tunnel with the preceding first shield machine and lining a part of the excavation cross section of the first tunnel with an excavable segment made of mortar or the like. As a continuous hole shield construction method that can shorten the construction period by excavating the second tunnel where the excavation cross-section partially overlaps with the first tunnel while excavating the lining material with the second shield machine (For example, refer to Patent Document 2).
Japanese Patent Laid-Open No. 4-155093 (page 3, FIGS. 1 to 6). Japanese Patent Laid-Open No. 1-192995 (second page, FIG. 2).

  In the tunnel merging method described in Patent Document 1, the trailing tunnel structure is constructed by superposing a large number of small diameter tunnel structures in the radial direction. For this reason, there exists a possibility that a construction cost may increase in construction of a trailing tunnel structure. In addition, the trailing tunnel structure is dug so as to gradually approach the axis of the preceding tunnel structure, and from the point of approach to the preceding tunnel structure, the outer periphery of the segment of the unstructured structure of the preceding tunnel structure It is constructed and merged while polymerizing. For this reason, the length of the merging portion becomes longer and the construction period becomes longer.

  In addition, in the continuous hole shield method described in Patent Document 2, a part of the first tunnel is covered with a segment that can be excavated, and the second shield machine that follows is excavated with the second shield machine while the second shield machine is excavated. Although a technique for constructing a large-section tunnel by forming a tunnel has been disclosed, there is no disclosure about the point that this construction method can be applied to the junction connection of a shield tunnel.

  By the way, recently, with the trend of increasing the depth of the tunnel, the construction method of the junction part of the shield tunnel has become a big issue. Conventionally, when a branch part is provided in a shield tunnel, there are many cases where the underground cutting and expansion method using ground improvement or the like is used. In addition, it is impossible to adopt the open-cut method in the private basement, and since the open-cut method is also limited in terms of water pressure, the length of the merging part is increased even under high water pressure at a large depth. Therefore, it is desired to develop a reliable underground connection method that can shorten the construction period and reduce the construction cost without any problems.

  Therefore, it is possible to connect to a certain bifurcation in the ground without using underground cutting and expansion method combined with an auxiliary construction method, and without increasing the length of the merged portion, thereby improving safety during construction. At the same time, there is a technical problem to be solved in order to shorten the construction period and reduce the construction cost, and to reliably perform the construction even under high water pressure, and the present invention aims to solve this problem.

  The present invention has been proposed in order to achieve the above-mentioned object, and the invention according to claim 1 is to connect a branch portion of a shield tunnel in which a branch tunnel having a circular cross section is joined to a main tunnel through an opening connecting portion. The branch line tunnel has two tunnel structures having a smaller diameter and a circular cross section than the branch line tunnel, and the axis lines of the branch line tunnel and the two tunnel structures are in the same direction and Three branch walls and a portion of each of the outer peripheral walls of the two tunnel structures are arranged so as to be in a positional relationship in which they are in contact with the outer peripheral wall of the main tunnel almost simultaneously. Connecting to a branch portion of a shield tunnel configured to be a circular tunnel and removing the opposing wall portion of the main tunnel and the branch tunnel and earth and sand interposed between the opposing wall portions to open the opening connecting portion The law provides.

  According to this configuration, the main tunnel is formed at the junction where a part of each outer peripheral wall of the branch tunnel and the two tunnel structures is in contact with the outer peripheral wall of the main tunnel while the three-circular tunnel is dug by the three-circular shield machine. By removing the opposing wall portion between the and the branch tunnel and the earth and sand interposed between the opposing wall portions, the opening connecting portion is opened, and the branch portion of the branch tunnel is connected to the main tunnel.

  In the invention according to claim 2, the freezing treatment is performed on the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures at the junction of the main tunnel and the three-circular tunnel. Later, a shield tunnel branch connecting method for opening the opening connecting portion is provided.

  According to this configuration, the main tunnel is formed at the junction where a part of each outer peripheral wall of the branch tunnel and the two tunnel structures is in contact with the outer peripheral wall of the main tunnel while the three-circular tunnel is dug by the three-circular shield machine. Freezing treatment is performed on the contact portion between the outer peripheral wall of each of the two tunnel structures and each outer peripheral wall of the two tunnel structures, and after forming a frozen water-stopping zone around the planned opening region of the opening connecting portion, By removing the opposing wall portion and the earth and sand interposed between the opposing wall portions, the opening connecting portion is opened, and the branch portion of the branch tunnel is connected to the main tunnel.

  According to a third aspect of the present invention, the ground is improved in the ground around the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures at the junction of the main tunnel and the three-circular tunnel. 2. The method for connecting branch portions of a shield tunnel according to claim 1, wherein the opening connecting portion is opened after the agent is injected and the water stop treatment is performed.

  According to this configuration, the main tunnel is formed at the junction where a part of each outer peripheral wall of the branch tunnel and the two tunnel structures is in contact with the outer peripheral wall of the main tunnel while the three-circular tunnel is dug by the three-circular shield machine. The ground improvement agent is injected into the ground around the contact area between the outer peripheral wall of the two tunnel structures and each of the outer peripheral walls of the two tunnel structures, water-stopping treatment is performed, and the ground improvement water-stopping zone is formed around the planned opening area of the opening communication part. After the formation, the opening connecting portion is opened by removing the opposing wall portion between the main line tunnel and the branch line tunnel and the earth and sand interposed between the opposing wall portions, and the branch portion tunnel connection to the main tunnel is established. Done.

  According to a fourth aspect of the present invention, an outer peripheral wall portion of the main tunnel in which a part of each outer peripheral wall of the two tunnel structures is in contact with the outer peripheral wall of the main tunnel is a shape of the outer peripheral wall of the tunnel structure. A branch tunnel connection method for a shield tunnel formed in a reverse R shape along the line is provided.

  According to this configuration, it is possible to increase the freeze-stop zone by bringing the outer peripheral walls of the two tunnel structures into contact with the respective reverse R-shaped portions formed on the outer peripheral wall portion of the main tunnel. Become.

  According to a fifth aspect of the present invention, an excavable material is embedded in the inverted R-shaped portion formed on the outer peripheral wall of the main tunnel, and the three-circular tunnel is moved to the main tunnel by the three-circular shield machine. And a shield tunnel branch connection method in which the material is excavated and removed by the three-round shield machine at the time of merging.

  According to this configuration, the material that can be excavated is embedded in the reverse R-shaped portion formed on the outer peripheral wall portion of the main tunnel, so that when the main tunnel is dug by the shield machine, the shield machine or the main tunnel is inserted into the main tunnel. There is no risk of water leakage.

  According to a sixth aspect of the present invention, there is provided a structural member before the opening connecting portion is opened after the freezing treatment is performed on the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures. We provide a method for connecting branch parts of linked shield tunnels.

  According to this configuration, the contact portion between the outer peripheral wall of the main tunnel and each outer peripheral wall of the two tunnel structures is firmly connected and held, and at the time of construction of the opening connection portion, leakage due to the impact of the construction is prevented. Thus, it is possible to reliably maintain the water-stopping property.

  The invention according to claim 7 is a shield tunnel structure in which a branch line tunnel having a circular cross section joins with a main line tunnel via an opening connecting part, and the branch line tunnel is more than the branch line tunnel. Two tunnel structures having a small diameter and a circular inner section covered with segments, the axis of the branch tunnel and the two tunnel structures are in the same direction, and the junction with the main tunnel A shield tunnel structure comprising a three-circular tunnel attached so that a part of the outer peripheral walls of the branch line tunnel and the two tunnel structures are in contact with each other substantially simultaneously with the outer peripheral wall of the main tunnel I will provide a.

  According to this configuration, the opening communication part between the main line tunnel and the branch line tunnel at the branch part is formed in such a manner that the three circular tunnels are dug by the three circular shield machine, and the outer peripheral walls of the branch line tunnel and the two tunnel structures. Shield tunnel with a branch by removing the opposing wall of the main tunnel and the branch tunnel and the earth and sand interposed between the opposing walls at the junction where part of the main tunnel touches the outer wall of the main tunnel The structure is realized.

  According to an eighth aspect of the present invention, an outer peripheral wall portion of the main tunnel, in which a part of each outer peripheral wall of the two tunnel structures contacts the outer peripheral wall of the main tunnel, has a shape of the outer peripheral wall of the tunnel structure. The shield tunnel structure formed in the reverse R shape along the line is provided.

  According to this configuration, when the freezing treatment is performed on the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures, each inverted R-shaped portion formed on the outer peripheral wall portion of the main tunnel. Since the outer peripheral walls of the two tunnel structures are in contact with each other, the contact area is increased and the freeze-stop zone can be increased.

  The invention according to claim 9 is the segment on each tunnel structure side and the segment on the main tunnel side in a portion where a part of each outer peripheral wall of the two tunnel structures contacts the outer peripheral wall of the main tunnel. Provides a shield tunnel structure in which a tension freezing pipe is previously installed.

  According to this configuration, the freezing process can be performed efficiently and reliably on the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures without requiring a separate freezing method. It becomes possible.

  The invention according to claim 10 provides a shield tunnel structure in which the outer peripheral wall on the main tunnel side and the outer peripheral wall on the tunnel structure side are connected by a structural member.

  According to this configuration, the contact portion between the outer peripheral wall of the main tunnel and each outer peripheral wall of the two tunnel structures is firmly connected and held, and the connection between the main tunnel and the branch tunnel is firmly held at the branch portion. It becomes possible to do.

  According to the first aspect of the present invention, it is possible to form an opening connecting portion having a necessary opening area in the ground without increasing the length of the joining portion between the main tunnel and the branch tunnel. Therefore, there is an advantage that the safety during construction can be improved and the work period can be shortened and the work cost can be reduced.

  The invention according to claim 2 forms an opening communication portion having a necessary opening area in the ground without taking a length of a joining portion of the main line tunnel and the branch line tunnel by freezing. Can do. Therefore, it is possible to perform branch connection without using a construction method such as underground cutting and expansion, improve safety during construction, shorten the construction period and reduce construction cost, and There is an advantage that it can be reliably constructed even under high water pressure.

  According to the invention of claim 3, by applying a water stop treatment by injecting a ground improvement agent, the required opening area in the ground can be increased without taking a length of the joining portion between the main tunnel and the branch tunnel. The opening communication part which has can be formed. Therefore, it is possible to perform branch connection without using a construction method such as underground cutting and expansion, improve safety during construction, shorten the construction period and reduce construction cost, and There is an advantage that it can be reliably constructed even under high water pressure.

  Since the invention according to claim 4 is formed in an inverted R shape along the shape of the outer peripheral wall of the tunnel structure, there is an advantage that the freeze-stop zone can be increased and the water-stop performance can be further improved. is there.

  According to the fifth aspect of the present invention, a material that can be excavated is embedded in an inverted R-shaped portion formed on the outer peripheral wall portion of the main tunnel, so that when the main tunnel is dug by the shield machine, There is an advantage that water can be prevented from leaking and can be constructed safely and efficiently even under high water pressure.

  According to the sixth aspect of the present invention, the contact portion between the outer peripheral wall of the main tunnel and each outer peripheral wall of the two tunnel structures is firmly connected and held, and leakage of water due to the impact of the construction is made at the time of construction of the opening communication portion. Is prevented, and the water stoppage can be reliably maintained.

  According to the seventh aspect of the present invention, an opening connecting portion having a necessary opening area in the ground is formed without increasing the length of the joining portion between the main tunnel and the branch tunnel. Therefore, there is an advantage that the construction period can be shortened and the construction cost can be reduced, and a low-cost shield tunnel structure can be realized.

  According to the eighth aspect of the present invention, the outer peripheral wall portion of the main tunnel is formed in an inverted R shape along the shape of the outer peripheral walls of the two tunnel structures. There is an advantage that the water stoppage can be further improved by increasing the zone.

  The invention according to claim 9 is an effective and reliable freezing water stop zone at the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures without requiring a separate freezing method. There is an advantage that can be formed.

  In the invention described in claim 10, since the outer peripheral wall on the main tunnel side and the outer peripheral wall on the tunnel structure side are connected by a structural member, the connection between the main tunnel and the branch tunnel at the branch portion is strong. There is an advantage that it can be held.

  Safety at the time of construction is possible without using construction methods such as underground cutting and expanding methods that use auxiliary construction methods and open-cut construction methods, etc., and without having to lengthen the length of the confluence, making it possible to reliably connect the junction in the ground. The purpose of this project is to shorten the construction period and reduce the construction cost, and also to ensure the construction even under high water pressure. A branch connection method, wherein the branch line tunnel has two tunnel structures having a smaller diameter and a circular cross section than the branch line tunnel, and the axis lines of the branch line tunnel and the two tunnel structures are the same. And a positional relationship in which a part of each outer peripheral wall of the branch tunnel and the two tunnel structures is in contact with the outer peripheral wall of the main tunnel almost simultaneously at the junction with the main tunnel. A three-circular tunnel attached to the main tunnel and the three-circular tunnel at the junction of the reverse R-shaped recess in the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures Are subjected to a freezing treatment by means of tension freezing tubes installed in advance on each of the outer peripheral wall on the main tunnel side and the outer peripheral wall on the tunnel structure side, and further in the region subjected to the freezing treatment or After connecting the outer peripheral wall on the main tunnel side and the outer peripheral wall on the tunnel structure side in the vicinity of the region with a structural member, the opposing wall portion between the main tunnel and the branch line tunnel, and between the opposing wall portions This was realized by removing the intervening earth and sand to form the opening communication part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a front sectional view before forming an opening connecting portion of a branch portion, FIG. 2 is an enlarged front sectional view showing a contact portion between the main tunnel and the tunnel structure, and FIG. 3 is an inverted R shape in the main tunnel. FIG. 4 is a plan view schematically showing the branching portion of the shield tunnel.

  First, the shield tunnel structure according to the shield tunnel branch connection method according to this embodiment and the configuration of each tunnel used in the shield tunnel structure will be described. As shown in FIGS. 1 and 4, the shield tunnel structure has a circular main line tunnel 2 with an inner peripheral wall covered with a segment 1, and an inner peripheral wall lined with a segment 3. Branch tunnels 4 having a small cross-section and a circular cross section are joined at the branch portion 5 via the opening connecting portion 6.

  While the main tunnel 2 is excavated by a circular shield machine (not shown), the segment 1 is formed in an annular shape on the inner peripheral wall of the excavation hole behind the circular shield machine. As shown in FIG. 2 and FIG. 3, the tunnel structure 10 is located at a part of each outer peripheral wall of the two tunnel structures 10, 10 to be described later on the outer peripheral wall of the main tunnel 2. An inverted R-shaped recess 7 corresponding to the shape of the outer peripheral wall is formed. In the inverted R-shaped concave portion 7, a material 8 such as digging mortar or synthetic resin is provided in order to prevent water leakage into the circular shield machine or the main tunnel 2 when the main tunnel 2 is dug by the circular shield machine. Embedded.

  On the other hand, when the opening connecting portion 6 is opened in the opposing wall portion between the branch tunnel 4 and the main tunnel 2, the branch line tunnel 4 has a predetermined opening planned area 6 a on the opposing wall portion. In order to form a freeze-stop zone in the vicinity region surrounding the planned opening region 6a, the following three-circular tunnel is configured.

  That is, the branch line tunnel 4 includes two tunnel structures 10, 10 having a smaller diameter than the branch line tunnel 4 and an inner peripheral wall covered with the segment 9. Each axis of each of the tunnel structures 10 and 10 is in the same direction, and a part of each of the outer peripheral walls of the branch tunnel 4 and the two tunnel structures 10 and 10 at the junction with the main tunnel 2 is It is configured as a three-circular tunnel that is attached so as to be in a positional relationship that contacts the outer peripheral wall of the main tunnel 2 almost simultaneously.

  The three-circular tunnel is excavated by a three-circular shield machine (not shown) from the beginning of the branch-line tunnel 4, and the segment 3 is circularly formed on the inner peripheral wall of the branch-line tunnel-side excavation hole behind the three-circular shield machine. Each segment 9 is formed in an annular shape on the inner peripheral wall of the excavation hole on the side of each tunnel structure.

  Then, the segment 9 on the side of each tunnel structure 10, 10 side and the side of the main tunnel 2 at the part where a part of each outer peripheral wall of the two tunnel structures 10, 10 is in contact with the outer peripheral wall of the main tunnel 2. Tension freezing tubes 11a and 11b are installed in advance in the segment 1, respectively.

  In addition, the opening after the freezing treatment by the tension freezing tubes 11a and 11b is performed on the contact portion 12 between the outer peripheral wall of the main tunnel 2 and the outer peripheral walls of the two tunnel structures 10 and 10. Before the connection portion 6 is opened, the segment 1 on the main tunnel 2 side in the region where the freezing treatment is performed or in the vicinity of the region in order to improve the impact resistance when the opening connection portion 6 is opened. A structural member 13 such as a tie bolt is driven from the inside of the main tunnel 2 between the tunnel structure 10 and the segment 9 on the side of each tunnel structure. In the example of FIGS. 1 and 2, the structural member 13 is driven into the planned opening region 6a side in the region subjected to the freezing process. The structural member 13 also functions to firmly hold the connection between the main tunnel 2 and the branch tunnel 4 at the branch portion 5 after construction.

  Next, a method for connecting the branching section between the main tunnel and the branch tunnel configured as described above will be described. While digging a three-circular tunnel with a three-circular shield machine, when the three-circular tunnel joins the main tunnel 2, the three-circular shield machine excavates and removes material 8 such as mortar and synthetic resin, The outer peripheral wall is brought into direct contact with the outer peripheral wall of the main tunnel 2 and a part of each outer peripheral wall of the two tunnel structures 10 and 10 is brought into contact with each inverted R-shaped recess 7 as shown in FIG. Keep in contact.

  In such a contact state, a low-temperature liquefied gas such as liquid nitrogen is sent to the tensioned freezing tubes 11a and 11b, and a part of each outer peripheral wall of the two tunnel structures 10 and 10 and the main tunnel 2 side. The contact portion 12 with each inverted R-shaped recess 7 is subjected to a freezing process to form a frozen water-stop zone in a region surrounding the planned opening region 6 a of the opening connecting portion 6. At this time, the outer peripheral walls of the two tunnel structures 10 and 10 are in contact with the respective reverse R-shaped concave portions 7 on the main tunnel 2 side, so that the area of the contact portion 12 is expanded, and the frozen water-stop zone Increases and a freeze-stop zone is efficiently formed in a region substantially surrounding the planned opening region 6a. In addition, although illustration is abbreviate | omitted, instead of forming a water stop zone by freezing, you may inject | pour a ground improvement agent into the ground around the contact part 12, and may perform a water stop process.

  Next, a structure is formed from the inside of the main tunnel 2 between the segment 1 on the main tunnel 2 side and the segment 9 on the tunnel structures 10 and 10 side in the freeze-stop zone or in the vicinity of the freeze-stop zone. The member 13 is driven to perform a process of firmly connecting and holding the contact portions 12 between the inverted R-shaped concave portions 7 on the main tunnel 2 side and the outer peripheral walls of the two tunnel structures 10 and 10, and the next opening To maintain the water stoppage during construction.

  After performing each of the required treatments, the opening connecting portion 6 is opened by removing the opposing wall portion between the main tunnel 2 and the branch tunnel 4 and the earth and sand interposed between the opposing wall portions, A branch part connection of the branch line tunnel 4 to the main line tunnel 2 is performed. In addition, after opening the opening connection part 6, it can also be utilized as a reinforcement member of the part which the said tunnel structures 10 and 10 opened.

  As described above, in the shield tunnel branch connection method according to the present embodiment and the shield tunnel structure by the method, a part of each outer peripheral wall of the two tunnel structures 10 and 10 and the main tunnel 2 side Freezing treatment is performed on the contact portions 12 with the respective inverted R-shaped concave portions 7 by the tension freezing tubes 11a and 11b to form a frozen water stop zone in a region substantially surrounding the planned opening region 6a of the opening communication portion 6; Furthermore, the structural member 13 was driven in and the water stoppage was reliably maintained at the time of opening construction of the opening communication portion 6, so that the length L of the merged portion between the main line tunnel 2 and the branch line tunnel 4 was not increased. The opening connecting part 6 having a necessary opening area in the ground can be formed. Therefore, it is possible to connect branching parts without using underground cutting and expanding methods combined with an auxiliary method for water stoppage, improving safety during construction, shortening the construction period and reducing construction costs In addition, it can be reliably constructed even under high water pressure.

  In this embodiment, in order to form a frozen water stop zone in the area surrounding the planned opening area 6a, the tension freezing pipe 11a is attached to the segment 9 on each tunnel structure 10, 10 side and the segment 1 on the main tunnel 2 side. 11b is installed in advance, but the tension freezing pipe is not installed in advance, and the three-circular shield machine side is dug into the main tunnel 2 while digging the three-circular tunnel with the three-circular shield machine. For example, a freezing tube may be inserted into the ground near the contact portion 12.

  Further, the present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

The figure shows an embodiment of the present invention.
Front sectional drawing before the opening connection part formation of the branch part in a shield tunnel structure. The front sectional view which expands and shows the contact part of the main line tunnel and tunnel structure in FIG. The expanded front sectional view of the part formed in the reverse R shape in the main line tunnel. The top view which shows typically the part of the branch part in a shield tunnel structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Main-line tunnel segment 2 Main-line tunnel 3 Branch-line tunnel segment 4 Branch-line tunnel 5 Branch part 6 Opening connection part 6a Planned opening area 7 Reverse R-shaped recessed part 8 Material such as mortar or synthetic resin 9 Tunnel structure segment 10 Tunnel structure 11a, 11b Tension freezing pipe 12 Contact part 13 Structural member

Claims (10)

A branch tunnel connection method for a shield tunnel that joins a branch tunnel with a circular cross-section to the main tunnel via an opening connecting portion,
The branch-line tunnel includes two tunnel structures having a smaller diameter and a circular cross section than the branch-line tunnel, and the axis of the branch-line tunnel and the two tunnel structures are in the same direction and the main-line tunnel. And a three-circular tunnel attached so that a part of the outer peripheral walls of the branch tunnel and the two tunnel structures are in contact with the outer peripheral wall of the main tunnel at the same time. A method for connecting a branch portion of a shield tunnel, wherein the facing connecting portion of the main tunnel and the branch tunnel and the earth and sand interposed between the facing walls are removed to open the opening connecting portion.   Freezing treatment is performed on the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures at the junction of the main tunnel and the three-circular tunnel, and then the opening connecting portion is opened. The method for connecting branching portions of a shield tunnel according to claim 1.   At the confluence of the main tunnel and the three-circular tunnel, water stopping treatment is performed by injecting a ground improver into the ground around the contact portion between the outer peripheral wall of the main tunnel and the outer peripheral walls of the two tunnel structures. 2. The method for connecting branching portions of a shield tunnel according to claim 1, wherein the opening connecting portion is opened after applying.   The outer peripheral wall portion of the main tunnel in which a part of each outer peripheral wall of the two tunnel structures contacts the outer peripheral wall of the main tunnel is formed in an inverted R shape along the shape of the outer peripheral wall of the tunnel structure. The branch tunnel connection method for a shield tunnel according to claim 1, 2, or 3.   The reverse R-shaped portion formed on the outer peripheral wall portion of the main tunnel is embedded with excavable material, and when the three-circular shield machine joins the three-circular tunnel to the main tunnel, the three-round shape is obtained. 5. The method for connecting a branch portion of a shield tunnel according to claim 4, wherein the material is excavated and removed by a shield machine.   The contact portion between the outer peripheral wall of the main tunnel and each outer peripheral wall of the two tunnel structures is connected with a structural member after the freezing process and before the opening connecting portion is opened. Item 6. A method for connecting a branch portion of a shield tunnel according to item 1, 2, 3, 4 or 5. The main tunnel is a shield tunnel structure having a branch portion where a branch tunnel having a circular cross section joins through an opening connecting portion,
The branch line tunnel has two tunnel structures having a smaller diameter than the branch line tunnel and a circular cross section whose inner peripheral wall is covered with a segment, and the axis lines of the branch line tunnel and the two tunnel structures are In the same direction and at a junction with the main tunnel, the branch line tunnel and a part of each outer peripheral wall of the two tunnel structures are in a positional relationship in which they are in contact with the outer peripheral wall of the main tunnel almost simultaneously. A shield tunnel structure comprising three attached circular tunnels.   The outer peripheral wall portion of the main tunnel in which a part of each outer peripheral wall of the two tunnel structures contacts the outer peripheral wall of the main tunnel is formed in an inverted R shape along the shape of the outer peripheral wall of the tunnel structure. The shield tunnel structure according to claim 7, wherein the shield tunnel structure is formed.   The tension freezing pipes are respectively provided in the segment on the tunnel structure side and the segment on the main tunnel side in a portion where a part of each outer peripheral wall of the two tunnel structures contacts the outer peripheral wall of the main tunnel. The shield tunnel structure according to claim 7 or 8, wherein: is installed in advance.   10. The shield tunnel structure according to claim 7, 8 or 9, wherein an outer peripheral wall on the main line tunnel side and an outer peripheral wall on the tunnel structure side are connected by a structural member.

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