Fascines

Abstract

Inflatable members for incorporation into a fascine are linked together at their ends by chains or other such flexible tension members, the tension in which is such as to cause at least local compression and flattening of the inflatable members where they are in contact with adjacent members. The forces so generated between adjacent members can prevent their tendency to rotate under the action of traffic crossing the fascine.

1 . A fascine comprising an assembly of parallel inflatable members of generally cylindrical form, wherein such members at least in the region of the crossing surface of the fascine are linked to adjacent members by flexible tension members at each end thereof, and wherein the effective lengths of the flexible tension members between their points of connection to the inflatable members are so related to the dimensions of the inflatable members as to cause at least local compression of adjacent such members when inflated and the generation of forces between those members sufficient substantially to resist their relative rotation when the fascine is crossed by vehicular traffic. 
   
   
       2 . An assembly of three parallel inflatable fascine members of generally cylindrical form linked together in a triangular pattern by flexible tension members at each end thereof, wherein the effective lengths of the flexible tension members between their points of connection to the inflatable members are so related to the dimensions of the inflatable members as to cause at least local compression of those members when inflated and the generation of forces between them sufficient substantially to resist their relative rotation when the assembly is crossed by vehicular traffic 
   
   
       3 . A fascine according to  claim 1  wherein the flexible tension members are connected to the inflatable members at positions substantially aligned with the central axes thereof 
   
   
       4 . A fascine according to  claim 1  wherein the flexible tension members are connected to the inflatable members at positions offset from the central axes thereof. 
   
   
       5 . A fascine according to  claim 1  where the effective lengths of the flexible tension members are in the range 80-98% of the unconstrained distance between their points of connection to adjacent inflatable members. 
   
   
       6 . A fascine according to  claim 5  where the effective lengths of the flexible tension members are in the range 88-95% of the unconstrained distance between their points of connection to adjacent inflatable members. 
   
   
       7 . A fascine according to  claim 1  wherein the degree of reduction of the diameters of the inflatable members where they are locally compressed is in the range 3-8%. 
   
   
       8 . A fascine according to  claim 7  wherein the degree of reduction of the diameters of the inflatable members where they are locally compressed is in the range 5-6%. 
   
   
       9 . The combination of a plurality of inflatable members of generally cylindrical form and a plurality of flexible tension members to link adjacent such inflatable members together at each end thereof, all adapted to be assembled into a fascine according to  claim 1 . 
   
   
       10 . A method of constructing a fascine comprising an assembly of parallel inflatable members of generally cylindrical form, which comprises linking at least such members intended to be in the region of the crossing surface of the fascine to adjacent members by flexible tension members at each end thereof and inflating the inflatable members, the effective lengths of the flexible tension members between their points of connection to the inflatable members being so related to the dimensions of the inflatable members as to cause at least local compression of adjacent such members when inflated and the generation of forces between those members sufficient substantially to resist their relative rotation when the fascine is crossed by vehicular traffic. 
   
   
       11 . A method of constructing an assembly of three parallel inflatable fascine members of generally cylindrical form, which comprises linking those members together in a triangular pattern by flexible tension members at each end thereof and inflating the inflatable members, the effective lengths of the flexible tension members between their points of connection to the inflatable members being so related to the dimensions of the inflatable members as to cause at least local compression of those members when inflated and the generation of forces between them sufficient substantially to resist their relative rotation when the assembly is crossed by vehicular traffic. 
   
   
       12 . A method according to  claim 10  wherein the flexible tension members comprise chains which, prior to completion of inflation of the inflatable members, are shortened by connecting non adjacent links together by means which are adapted to break under the tension in the shortened chains generated during inflation.