JP2006233626A - Tunnel structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tunnel structure reducing the damage of a tunnel wall surface following fault vibration displacement at the occurrence of an earthquake of a tunnel passing through a fault in a rock-bed. <P>SOLUTION: An outside wall body 8 integrated with the wall surface of the rock-bed is formed of a wall surface of high rigidity formed with a widened open-cut part 3 across the fault 2. An inside wall body 9 having the same inner void cross section as a lining part of a normal lining 5 is provided in a position separated from the outside wall body 8. The inside wall body 9 has a plurality of ring bodies 10 connected in an axial direction and connected to anchor part ring bodies 12 integrated with the lining of the normal lining 5. A mutual joint part of the ring bodies 10, 12 is provided with an expansion joint 13 allowing sliding displacement in the axial direction of the tunnel. Leg bodies 14 formed of base isolating members are installed between the inside wall body 9 and the outside wall body 8 to constitute a base isolating structure in which displacement in a support direction is allowed. A seal part 15 for preventing the outflow of seepage water and preventing falling-in is installed at an opening of the fault 2 exposed to the widened and open-cut rock-bed surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  This invention relates to tunnel wall surface due to discontinuous surface vibration displacement at the time of earthquake occurrence in the vicinity of tunnel penetration position of large-scale discontinuous surface such as faults existing in rock mass in the design and construction of underground space such as tunnel in civil engineering field The present invention relates to a tunnel structure for reducing or minimizing damage such as collapse or collapse.

  When excavating underground spaces such as tunnels in the rock mass, it is necessary to pierce large discontinuities such as faults existing in the rock mass. New Austrian Tunneling Method (NATM, New Austrian Tunneling Method), where the tunnel wall is integrated with cement, steel, rock bolts, and other highly rigid materials, and is supported immediately after rock excavation. As a result, tunnel construction that winds up the perforations of discontinuous surfaces such as faults in the bedrock with a thick wall has been put to practical use.

  In practical tunneling methods, the tunnel wall surface is formed as a continuous rigid body similar to the open wall of the rock mass, so the strain relief and stress state between the continuous rock mass and discontinuous faults are different when an earthquake occurs. Inability to cope with relative displacement vibrations that depend on the level of damage caused by the collapse or collapse of the tunnel wall around a large discontinuous surface such as a fault, which cannot cope with the deformation of a discontinuous surface such as a fault Existed.

As a tunnel structure corresponding to the ground deformation at the time of such an earthquake, for example, there is a conventional technique as shown below.
JP 2000-64790 A JP 2001-55893 A JP 2000-204891 A

  Patent Document 1 describes a tunnel structure in which a dynamic earth pressure buffering region is provided between a tunnel and a surrounding natural ground, and this dynamic earth pressure buffering region includes a support that supports earth pressure from the peripheral natural ground, It was comprised from the buffer body arrange | positioned inside this. The support is a wall made of mortar or concrete, and the shock absorber is made by enclosing a dynamic earth pressure buffer material in an elastic bag, and this dynamic earth pressure buffer material is solidified in a fluidized state after injection and then solidified. For example, urethane rubber that can absorb energy when subjected to forced deformation has been adopted.

  Patent Document 2 discloses a tunnel structure in which a sliding material is mounted on the outer peripheral surface of a tunnel housing. This sliding material insulates the tunnel from the ground by generating a slip between the ground and the frame, cuts off the transmission of ground strain to the tunnel, and reduces the cross-sectional force of the frame generated during an earthquake. there were.

  Further, Patent Document 3 discloses a tunnel structure having a ring-shaped flexible member inside, and this flexible member has a length longer than the width of the fault crushing zone, and both ends thereof are faulted. It was fixed to the lining part with a ring-shaped cross section arranged across. The aim was to secure a tunnel function even at the time of fault destruction by deforming the non-fixed area avoiding the constraint by the lining part between the fixed areas at the time of fault destruction.

  However, conventional tunnel structures with a dynamic earth pressure buffering area and tunnel structures with sliding materials attached to the outer peripheral surface of the frame cannot handle large displacement vibrations on discontinuous surfaces such as existing faults that are most likely to deform when an earthquake occurs. It was. That is, most of the rock behavior during an earthquake depends on deformation such as slip and dilation along the discontinuous surface such as existing faults, and the stress state change in the rock mass also appears prominently on these discontinuous surfaces, When an earthquake occurs, large three-axis displacement vibrations are likely to occur on the discontinuous surface, and in the conventional tunnel structure with cushioning material and sliding material, the rock mass and the tunnel frame are in full contact with each other through these intermediate materials. However, the triaxial seismic vibration of the rock mass was directly transmitted to the tunnel wall surface, and could not prevent the tunnel wall surface from collapsing or collapsing around discontinuous surfaces such as faults.

  The tunnel structure with a ring-shaped flexible member inside can be applied to pipe facilities such as water and sewage systems, but for railways and automobiles that must maintain a rigid wall surface in the event of an earthquake. It could not be applied to the tunnel structure.

  The present invention has been made to solve the above-mentioned problems of the conventional tunnel structure, and reduces the damage of the tunnel wall caused by the fault vibration displacement at the time of the earthquake occurrence of the tunnel penetrating the fault in the rock, The object is to provide a tunnel structure in which the wall surface of the tunnel is maintained regardless of the destruction or collapse of the wall surface due to the earthquake. Another object of the present invention is to provide a tunnel structure that has a seismic isolation structure that does not transmit the vibration at the time of the earthquake to the tunnel wall surface, and that can be repaired promptly even when damage such as collapse occurs on the rock wall surface.

  In order to solve the above-mentioned problems, the tunnel structure of the present invention is a tunnel structure constructed by excavating the inside of a rock having a large scale discontinuous surface such as a fault. It has an outer wall body formed on a surface and an inner wall body made of a rigid body constructed at a distance from the outer wall body at least at the position of the discontinuous surface.

  When a large-scale fault penetrating part that is predicted to vibrate in the event of an earthquake during tunnel excavation is encountered, widening is performed across this discontinuous surface part. Fixing regions are provided at both ends of the widened portion, and a normal lining portion having a general cross section on the outside thereof is integrally connected to an inner wall body and an outer wall body sandwiched therebetween. The outer wall body has a support structure similar to that of the normal lining portion, and is a highly rigid wall surface made of, for example, rock bolts, sprayed concrete, grout and the like, and the support body is integrated with the rock wall surface.

  Considering the amount of discontinuous surface displacement that can occur during an earthquake, the inner wall body is installed at a position sufficiently separated from the outer wall body so that the rock surface that has been displaced by vibration does not come into contact. The inner wall body usually has the same inner air section as the lining part, but is structured to withstand even if a discontinuous surface collapses or collapses during an earthquake. The inner wall body is constructed by assembling a concrete or steel member divided in the circumferential direction at the widened portion and fixing it to the normal lining portion.

  The double tunnel structure separating the rock mass support from the tunnel wall by widening the vicinity of the tunnel penetration position on the discontinuous surface, to the tunnel structure and its wall with the relative displacement difference due to the vibration displacement of the rock around the fault due to the earthquake Avoid direct propagation of.

  The inner wall body in the tunnel structure according to claim 2 is provided with an expansion joint capable of allowing sliding displacement in the tunnel axial direction. The installation position and the number of locations of the expansion joint are appropriately determined according to the length of the widened portion, the properties of the discontinuous surface, and the like. The expansion joint is provided in the circumferential direction of the inner wall body so that only an axial displacement is possible and the displacement in the radial direction can be restricted. When providing expansion joints at a plurality of locations, a plurality of ring-shaped tunnel wall surfaces are joined to form an inner wall body.

  The inner wall body in the tunnel structure according to claim 3 is supported by a seismic isolation member protruding from the outer wall body. A leg body made of a seismic isolation member is installed between the outer side wall body and the inner side wall body to constitute a seismic isolation structure in which displacement in the support direction is allowed. The seismic isolation member is an appropriate combination of an isolator having strength and rigidity capable of supporting the entire inner wall body weight and sufficiently soft characteristics in the horizontal direction of the member and a damper having damping performance.

  5. A seal material made of a relatively lightweight material that can be deformed to prevent permeation water outflow and collapse prevention is provided at the opening portion of the discontinuous surface exposed to the rock surface that has been widened and cut in the tunnel structure according to claim 4. It is characterized by this. As the sealing material, for example, the opening is covered with a coating film made of synthetic resin, synthetic rubber or the like, and a net or the like is further installed as a countermeasure against collapse. The opening of the discontinuous surface is not closed by a highly rigid member so that it can be easily deformed during earthquake vibration.

  The tunnel structure of the present invention has an outer wall formed on the rock surface that has been widened and opened, and an inner wall body that is separated from the outer wall, so that it becomes a double tunnel structure that separates the rock support and the wall surface of the tunnel. It is possible to avoid the propagation of the tunnel structure with the relative displacement discrepancy accompanying the vibration displacement of the surrounding rock mass of the fault and its direct propagation to the wall surface, and to reduce the damage of the tunnel wall surface.

  In other words, even if a failure or collapse occurs near a discontinuous surface such as a fault that is most likely to be damaged or collapsed during an earthquake, at least the tunnel wall surface can be maintained and damage caused by passage through the tunnel during an emergency disaster can be maintained. It becomes possible to minimize. In addition, because the outer wall and the inner wall are separated from each other, even when large-scale faults such as large faults after a disaster have occurred, repairing collapses and collapses due to rock mass fluctuations such as earthquakes is possible. Repair becomes easier, and the repair period and scale can be reduced.

  The inner wall body in the tunnel structure according to claim 2 is provided with an expansion joint capable of allowing sliding displacement in the tunnel axial direction, so even if relative displacement occurs in the axial direction across the discontinuous surface, the displacement It can absorb the body and prevent the body damage. Further, since the inner wall body in the tunnel structure according to claim 3 is supported by a seismic isolation member protruding from the outer wall body, it is possible to prevent transmission of vibration in the triaxial direction of the rock wall surface to the tunnel wall surface. It is possible to realize a damage reduction structure that does not directly transmit the damage of collapse and collapse due to the vibration of the discrepancy displacement generated at the discontinuous surface in the tunnel to the inner wall of the tunnel.

  In the tunnel structure according to claim 4, since the opening of the discontinuous surface is covered with a seal material made of a relatively lightweight material that can be deformed, it is possible to prevent the outflow of infiltrated water or the like that occurs when an earthquake occurs. It is also possible to prevent the discontinuity from collapsing. Because damage such as collapse and collapse due to large-scale rock mass changes such as earthquakes concentrates on discontinuous surfaces such as large faults existing in the rock mass, if the opening of the discontinuous surface is covered with a rigid member The part to be destroyed becomes larger. For this reason, the opening of the discontinuous surface is easily deformed at the time of earthquake vibration, and if it is covered with a material that is not destroyed, damage such as collapse can be reduced.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a cross-sectional view of a tunnel structure with a double-structure seismic isolation that prevents relative vibration displacements associated with earthquakes from being transmitted directly to the tunnel wall in the rock surrounding the discontinuous surface such as faults. .

  In construction of underground space such as a practical tunnel, the wall surface of the tunnel in the rock mass 1 is directly joined to the rock excavation wall surface by cement or the like, but in the structure of the present invention, a discontinuous surface such as the fault 2 in the rock mass 1 The structure is such that relative displacement during an earthquake or the like due to the rock 1 not being continuous in the vicinity, for example, displacement in the direction of the arrow shown in FIG.

  When excavating the rock mass 1, in the vicinity of the discontinuous surface such as the fault 2, the widened excavation portion 3 is provided across the surface, and the rock bolt 6 is sprayed on the rock wall surface in the same manner as the structure of the normal lining 5 of the general section excavation portion 4. Concrete 7 or grout is placed to form an outer wall 8 that is integrated with the rock wall surface with a highly rigid wall surface. An inner wall body 9 having the same inner cross section as the lining portion of the lining 5 is provided at a position separated from the outer wall body 8.

  The inner wall body 9 has a configuration in which a plurality of ring bodies 10 assembled in the widened cut-out part 3 are connected in the axial direction by a concrete or steel member divided in the circumferential direction. 11 is connected to a fixing unit ring body 12 that is integrated with the lining of the normal lining 5.

  The joints of these ring bodies 10 and 12 are provided with expansion joints 13 that can allow sliding displacement in the tunnel axis direction. Considering the amount of discontinuous surface displacement that can occur during an earthquake, the inner wall body 9 is installed at a position that is sufficiently separated from the outer wall body 8 so as not to contact the rock surface that has been displaced by vibration. The leg body 14 is installed to constitute a seismic isolation structure in which displacement in the support direction is allowed. In addition, a seal portion 15 is installed at the opening of the fault 2 exposed to the rock surface that has been widened and cut out to prevent the seepage water from flowing out and to prevent the collapse.

  Details of the seal portion will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view of the seal portion. The discontinuous surface such as fault 2 existing in the bedrock is open to the cut wall, and when the earthquake occurs, the discrepancy shown in the direction of the arrow in FIG. 2 on the discontinuous surface such as fault 2 is the weakest part in the rock. When relative vibration displacement occurs, the seepage water flows out from the opening and collapse of collapsed rocks occurs.

  For this reason, rock bolts 6, sprayed concrete, grouts 7 and the like are placed on the bedrock of the widened cut-out portion 3 to construct a solid outer wall body 8, but a coating film 15a made of a resin material or the like is formed at the opening of the fault 2 A net member 15b or the like is installed by an anchor 15c to protect against flooding and microdisintegration.

  Next, details of the expansion joint of the inner wall body will be described with reference to FIGS. 3 is an enlarged sectional view of the inner wall body fixing portion, and FIG. 4 is a plan view and a sectional view of the expansion joint. The fixing part ring body 12 is usually integrated with the lining of the lining 5, but an expansion joint 13 is provided at the end in the direction of the widened cut-out part 3 and is connected to the ring body 10 of the inner wall body 9. The expansion joint 13 is provided in the circumferential direction of the inner wall body 9, and is only capable of displacement in the tunnel axis direction indicated by a plan view arrow in FIG. 4B, and is a sectional view so that the radial displacement can be constrained. The step part 13a shown in FIG. The expansion joint 13 has a structure similar to a slide structure used for an existing bridge floor slab or the like, and is a connection structure made of steel or the like.

  Next, the structure of a seismic isolation member is demonstrated based on FIG.5 and FIG.6. FIG. 5 is a cross-sectional view showing the VV cross section of FIG. 1, and FIG. 6 is a cross-sectional view showing an example of the seismic isolation member. The seismic isolation member is configured so that the displacement of the outer wall body 8 combined with the rock wall surface is not directly transmitted to the ring body 10 which is the tunnel wall surface of the inner wall body 9 via the leg body 14. An isolator having strength and rigidity capable of supporting the entire weight of the inner wall body 9 and sufficiently soft in the horizontal direction of the member and a damper having damping performance are appropriately combined. The legs 14 having a seismic isolation function are arranged radially and have a three-dimensional seismic isolation function.

  As an example of the seismic isolation member, the laminated rubber shown in FIG. 6 (a) is laminated and bonded with thin rubber sheets 14a and steel plates 14b alternately in order to suppress the influence of vibration displacement in the direction of the support axis by suppressing the rigidity in the support. A soft steel material 14c is press-fitted into the central portion. When the laminated steel is subjected to shear deformation, the soft steel material 14c is plastically deformed so that an isolator with a built-in damper that absorbs energy is obtained. The steel damper shown in FIG. 6 (b) can follow a large horizontal deformation and a vertical deformation accompanying it with a structure in which the center of the steel is gradually narrowed. In the oil damper shown in Fig. 6 (c), the structure of the oil cylinder is incorporated in the axial direction to support the outer peripheral structure and the inner peripheral structure, and the seismic isolation in the support axial direction is realized by the change of the oil pressure in the cylinder. Is done.

  The tunnel structure of the present invention can be widely applied not only to mountain tunnels but also to structures in underground spaces formed by excavating rock.

It is sectional drawing of a tunnel structure. It is an expanded sectional view of a seal part. It is an expanded sectional view of an inner wall body fixing part. It is the top view and sectional drawing of an expansion joint. It is sectional drawing which shows the VV cross section of FIG. It is sectional drawing which shows an example of a seismic isolation member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rock bed 2 Fault 3 Widening excavation part 4 General cross-section excavation part 5 Normal lining 6 Rock bolt 7 Spraying concrete 8 Outer side wall body 9 Inner side wall body 10 Ring body 11 Fixing area 12 Fixing part ring body 13 Expansion joint 14 Leg body 15 Seal part

Claims (4)

  In a tunnel structure constructed by excavating the inside of a rock having a large discontinuous surface such as a fault, an outer wall body formed on the rock surface obtained by widening the vicinity of the tunnel penetration position of the discontinuous surface, and at least the discontinuous surface A tunnel structure characterized by having an inner wall body made of a rigid body constructed at a position spaced apart from an outer wall body.   The tunnel structure according to claim 1, wherein the inner wall body includes an expansion joint capable of allowing a slide displacement in a tunnel axial direction.   The tunnel structure according to claim 2, wherein the inner wall body is supported by a seismic isolation member protruding from the outer wall body.   The opening portion of the discontinuous surface exposed to the rock surface that has been widened and cut open is provided with a seal material made of a relatively lightweight material that can be deformed to prevent outflow of osmotic water and to prevent collapse. 1. The tunnel structure according to 1.

Images