Method for constructing a tunnel course, and structural element for use by the method

Abstract

A method and a structural element for the construction of a directionally flexible and watertight tunnel lining ( 1 ) or tunnel course ( 1 ), the method using pre-fabricated elements of concrete or sandwich structure ( 3, 4, 5; 73;73 ′). Interspace between such elements and extending transversely of the direction of the tunnel course or tunnel lining receives an interspace cast ( 14 ) using an outer flexible formwork ( 2 ) in the form of skirts ( 2′, 2 ″) attached to the outside of the elements ( 3, 4, 5; 73, 73 ′), and which through interconnection ( 11 ) thereof form a flexible, “bag-like” formwork ( 2 ) on the outside of the elements ( 3, 4, 5; 73, 73 ′). Together with conventional formwork ( 12 ) on the inside of the elements ( 3, 4, 5; 73, 73 ′) there is formed a defined cavity ( 13 ) which can be filled with injectable mass of concrete. After the concrete has hardened it will provide support to the installed elements ( 3, 4, 5; 73, 73 ′) as well as providing support relative to exposed surface portion of rock surface ( 10 ). The elements ( 3, 4, 5; 73, 73 ′) can be provided on the outside with a membrane ( 17 ). Further, the elements can be provided with injection paths ( 16 ) in order to at any time establish a completely watertight tunnel lining ( 1 ).

1 . A method for constructing tunnel courses which are completely or partly surrounded by rock formations and/or are located in open air, the tunnel course in its longitudinal direction consisting of a plurality of mutually separate, pre-fabricated tunnel arch forming structural elements which are intended to be sealed against each other, comprising:
 a) installing along a tunnel course at each longitudinal side thereof tunnel element bases and cast these onto masses adjacent the bases,   b) placing from recesses on the bases successively in the longitudinal direction of the tunnel course with mutual distance self-supportive sections each consisting of at least two of said tunnel arch forming elements, wherein the tunnel arch forming elements are made of concrete or sandwich structure,   c) arranging at the outside of the sections at the opening therebetween an outer, flexible formwork,   d) arranging formwork equipment across the opening between the sections at the inside of the sections,   e) injecting concrete through the formwork equipment into a space defined by adjacent tunnel arch forming element sections, said outer flexible formwork and said formwork equipment, so that injected concrete expands the outer, flexible formwork outwardly and laterally at the outside of the tunnel course, and   f) letting the injected concrete harden.   
     
     
         2 . The method according to  claim 1 , the tunnel course being surrounded by rock masses, wherein feature a) further includes providing the base with a skirt attached thereto along a face of the base facing the inside of the tunnel course, the skirt being configured to form a flexible formwork, and fixedly casting the base into place by filling concrete into a space bordered by the base, neighbouring rock masses and the skirt. 
     
     
         3 . The method according to  claim 1 , wherein said tunnel arch forming elements are made of concrete and provided on their outside with a watertight membrane. 
     
     
         4 . The method according to  claim 1 , wherein the outer flexible formwork is provided by using two longitudinal skirts at the upright edges of adjacent tunnel arch forming element, and interconnecting the neighbouring skirts to form the flexible formwork. 
     
     
         5 . The method according to  claim 1 , wherein each skirt is configured as a net, wherein concrete is injected into said space of which the flexible formwork forms a part until filled by concrete, and wherein some concrete is allowed to penetrate the flexible formwork provided by the interconnected net configured skirts. 
     
     
         6 . The method according to  claim 4 , the tunnel course being surrounded by rock masses, further comprising letting the injected concrete press the flexible formwork to expand in order to contact a portion of adjacent rock mass. 
     
     
         7 . The method according to  claim 1 , comprising after the hardening of concrete in feature f) injecting via pre-arranged injection path in upright contact faces on the tunnel arch forming elements sealing mass between the injected, hardened concrete and the adjacent tunnel sections. 
     
     
         8 . The method according to  claim 1 , comprising injecting, via pre-arranged injection path at contact faces on the tunnel arch forming elements in direction of the tunnel course, sealing mass between adjacent elements of a tunnel section. 
     
     
         9 . The method according to  claim 1 , wherein a compressible, open-pore mat is located between contact faces of the tunnel arch forming elements in the direction of the tunnel course, and wherein sealing mass is injected via the mat into the space between the contact faces. 
     
     
         10 . The method according to  claim 1 , further providing a puncturable mat or cushion structure containing sealing mass between opposite edge faces of the tunnel elements located in the direction of the tunnel course, and upon joining the elements to form a tunnel section thereby puncturing the mat or cushion structure to form a sealing between the opposite contact faces. 
     
     
         11 . The method according to  claim 1 , wherein in a recess of the bases there is located a puncturable mat or cushion structure containing sealing mass to interact with lowermost elements of a tunnel section, and causing the mat or cushion structure to be punctured when the lowermost elements enter the respective recess. 
     
     
         12 . The method according to  claim 1 , comprising prior to step b) locating in recesses in the bases a fluid spreading mat, and injecting therein a sealing mass to spread the sealing mass in a space between the recesses and lowermost elements of a tunnel section entered into the recesses. 
     
     
         13 . The method according to  claim 1 , the tunnel course being surrounded by rock masses, further comprising injecting into cavities between the tunnel sections and the rock masses filler means in the form of concrete or loose filler material. 
     
     
         14 . The method according to  claim 1 , the tunnel course being located in open air, further comprising applying concrete or other covering means to the outside of tunnel sections formed by tunnel arch forming elements. 
     
     
         15 . The method according to  claim 1 , wherein, following feature f), the tunnel course is completed by casting a tunnel foundation after a membrane is established on a smoothing cast on a bed formed by rock or filler material. 
     
     
         16 . A structural element for use in manufacturing a tunnel course according to the method of  claim 1 , wherein the element is of concrete or a sandwich structure, and wherein the element on the outside thereof at either edge to be positioned upright and extending in a direction transversely of the longitudinal direction of the tunnel and the element, is provided with a first, outer, flexible formwork half which is configured to be interconnectable with a corresponding second, outer, flexible formwork half on a neighbouring further structural element when said further structural element is positioned next to the first mentioned element, to form a flexible formwork for receiving concrete injected between the adjacent elements and into the flexible formwork. 
     
     
         17 . The structural element according to  claim 16 , wherein the structural element is made of concrete, and wherein its outside face is provided with a watertight membrane. 
     
     
         18 . The structural element according to  claim 16 , wherein said outer, flexible formwork halves each consists of attached skirt configured as a net, injectable concrete being locatable in a space defined by the interconnected, flexible formwork halves and opposite upright side edges of adjacent tunnel arch forming structural elements. 
     
     
         19 . The structural element according to  claim 18 , wherein the net has a mesh width which is small enough to prevent the largest sized added material of the injected concrete to penetrate the net configured flexible formwork, and large enough to allow smaller sized parts of the added material over at least a part of the injection period to penetrate the flexible formwork. 
     
     
         20 . The structural element according to  claim 16 , configured for a tunnel lining surrounded by rock masses, wherein the flexible formwork has a property of flexibility which allows injected concrete to press the flexible formwork to come to rest against a portion of the rock mass. 
     
     
         21 . The structural element according to  claim 16 , comprising an injection path moulded-in or arranged in the contact faces of the structural element which extend transversely of the tunnel course, the injection path capable of causing sealing mass to be injected into a space between injected, hardened concrete forming an interspace cast and tunnel arch forming elements adjacent thereto. 
     
     
         22 . The structural element according to  claim 16 , wherein an injection path, located in at least one of the contact faces of the structural element which extends in the direction of the tunnel course, is provided to allow injection of sealing mass between contact faces of adjacent elements which extend in such a direction. 
     
     
         23 . The structural element according to  claim 16 , wherein in a space between contact faces of elements extending in the direction of the tunnel course, there is arrangable a compressible, open-pore mat capable of receiving sealing mass to seal said space. 
     
     
         24 . The structural element according to  claim 16 , wherein sealing in a space between contact faces of elements extending in the direction of the tunnel course is provided by a puncturable mat or cushion structure which contains a sealing mass and to be located in said space. 
     
     
         25 . The structural element according to  claim 16 , further comprising a puncturable mat and cushion structure containing sealing mass to provide sealing between lowermost elements of the tunnel arch forming elements and corresponding base elements below shaped to receive a lowermost end of said lowermost elements.