Patent Publication Number: US-4545701-A

Title: Tunnel wall structure

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a tunnel wall structure constructed by a shield process. 
     In the prior art constructing a tunnel wall structure by the shield process, reinforced concrete segments are assembled progressively using an erector with the progress of a shield machine. There have been proposed various means for joining the concrete segments at the time of the assembly. In one of these means, which is most extensively used in practice, joint members are burried end portions of adjacent concrete segments and clamped by bolts and nuts. 
     The wall structure that is obtained by assembling the concrete segments in the form of a ring is required that it can perfectly withstand the earth pressure as a whole. In additions the individual concrete segments in the ring-like wall assembly experience a bending moment, which is highest on the inner wall surface. Accordingly, the joints that connect adjacent concrete segments in the peripheral direction of the wall structure are required to have a high tensile strength. 
     Meanwhile, individual concrete segments have to be comparatively readily positioned in their width direction, i.e., in the direction of the tunnel, and the tunnel wall structure has to be constructed comparatively speedily. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1 and 2 are sectional views of a tunnel wall structure taken in a direction perpendicular to the direction of a tunnel and in the direction of the tunnel respectively; 
     FIGS. 3 and 4 are plan views showing a concrete segment A and a concrete segment K respectively; 
     FIGS. 5, 6 and 7 are views showing a segment A taken in the peripheral direction and width direction thereof; 
     FIGS. 8, 9 and 10 are respectively a front view, a plan view and a side view showing a joint member for peripheral direction; 
     FIGS. 11,12 and 13 show a positioning member in a front view and sectional views; and 
     FIGS. 14 and 15 are sectional views showing a joint in peripheral direction and a joint in width direction respectively. 
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     The tunnel wall structure according to the invention has been developed to meet the demands noted above. The embodiment of the invention will now be described in detail with reference to the drawings. 
     With reference to FIGS. 1-7 of the drawing, the tunnel wall structure according to the invention is obtained by assembling three different kinds of concrete segments A, B and K in the form of a ring and joining such ring-like structures one after another in the width direction of the segments, i.e., in the direction of the tunnel. It will be appreciated from FIG. 1 that the ring has an axis and therefore, from FIGS. 1-3, that the segments, A for example, have circumferentially opposite ends A1 and axially opposite sides A2. 
     Each concrete segment is provided with joints 1 for the circumferential direction and thus at opposite ends A1 thereof, and joints 2 in the width or axial direction and thus at opposite sides A2 thereof. Further, each concrete segment is provided at its center with a tube-like member 3, into which an end of an erector is screwed at the time of the assembly, and through which a filler material is charged after the ring-like structure has been assembled. Further, each concrete segment has burried inserts 4 provided at suitable positions, which are used for mounting internal construction materials and also for mounting guide members at the time of the assembly. 
     The joint 1 for the peripheral direction comprises a joint member 5 which is cast from steel. As seen in FIGS. 8, 9, 10 and 14, member 5 has a central bolt hole 6 and is also provided with recesses 7 formed in a portion surrounding the bolt hole 6. The joint member 5 of joint 1 also has opposite side projections 5a, which are radially spaced from bolt hole 6 and formed with threaded holes 9 through which anchor bars 8 are screwed. When the joint member 5 is buried in the concrete segment, a block-out 10 is formed on its inner side such that it communicates with the recesses 7. 
     In assembly, circumferentially ajacent concrete segments are abutted in the circumferential direction so that the mating joint members 5 also abut each other. In this state, a bolt 11 is passed through the aligned bolt holes 6 of the two joint members 5, and a nut 12 is fitted on the bolt 11 and tightened. The segments A and B are united together progressively such that the ring-like wall structure is constructed progressively upwards. Finally, a key segment K is fitted to complete a ring-like structure. Gaps 13 formed between adjacent segments are filled with a seal material. 
     As will be seen in FIG. 3, joint 2 for the axial direction is constituted by a curved bolt hole 15 which is open to the joint boundary or segment side A2 on one hand and to an inner block-out 14 on the other hand. When axially adjacent segments are to be joined together, as shown in FIG. 14, disc-like concave and convex positioning members 16 and 17 shown in FIGS. 11-13 are provided at the joint boundary defined by sides A2 and between the mating bolt holes 15. These positioning members 16 and 17 have openings 16a and 17a therethrough, respectively, and are secured in position by anchor members 18. A guide pipe 19 is provided in the bolt hole 15 in a portion thereof adjacent to the inner end open to the block-out 14. 
     In assembly, the concave and convex positioning members 16 and 17 of axially adjacent concrete segments are mated with each other. In this state, a curved bolt 20 is passed through the mated and communicated bolt holes 15, and a nut 21 is fitted on the bolt 20 and tightened. In this way, axially adjacent concrete segments can be assembled together in the direction of the tunnel. Gaps 13 formed between adjacent concrete segments abutted in the axial direction thereof are also filled with a seal material. 
     In the Figures, designated at 22 is concrete, and at 23 reinforcing bars. 
     As has been described in the foregoing, according to the invention individual concrete segments are united together in the circumferential direction by joining together abutted steel casting joint members, which are secured to the abutted concrete segments by anchor bars and provide for a comparatively high mechanical strength, with a bolt and a nut. Thus, it is possible to obtain an assembly and joints of a high tensile strength. Also, the assembling work itself is simple like the prior art assembly using bolt and nut. 
     Further, use is made of concave and convex positioning members for the assembly of adjacent concrete segments in their axial direction to facilitate the positioning of the segments and alignment of mated bolt holes. The positioning members further have an effect of reinforcing the bolt holes and also improving the shearing strength after the concrete segments are assembled. The invention is thus very beneficial in industry.