US 4,068,488 A · Method of backfilling pipeline trenches

Abstract

A trench containing a pipeline is backfilled by temporarily supporting the pipeline at grade in the trench on deflatable airbags spaced along the bottom of the trench. The trench is then backfilled below and around the pipe by pneumatically blowing a granular fill material into the trench first beneath the pipe and then progressively upwardly about its opposite sides to about its spring line so as simultaneously to backfill the trench and uniformly compact the fill material about the pipe without leaving any voids. The fill material is blown into the trench through a pair of opposed air ducts with upturned lower outlet ends extending into the trench on opposite sides of the pipe so that backfilling progresses upwardly on opposite sides of the pipe simultaneously. As backfilling operation progresses along the trench and approaches each support pad, the pad is deflated and removed so that the operation can proceed uninterruptedly. After the trench is pneumatically backfilled to the spring line of the pipe in the aforesaid manner, the upper portion of the trench to the soil surface can be backfilled in a conventional manner.

Claims12

Dependent claims

A method of backfilling a trench containing a pipeline comprising:

temporarily supporting said pipeline at a desired final position and grade within said trench spaced from the opposite sides of said trench and spaced above the bottom of the trench on removable support pads spaced at intervals along the bottom of said trench,
at a portion of said pipeline unsupported by said support pads blowing under pneumatic pressure a granular fill material into said trench first below and into the space beneath and about said pipeline and then progressively upwardly about and along the opposite sides of said pipeline to fill the trench spaces about the pipeline to at least about the spring line thereof, said fill material being blown at a velocity sufficient to simultaneously backfill said trench and compact said granular fill material to a substantially uniform desired final density about said pipeline to support the same at its final position and grade within said trench, whereby subsequent compaction of said fill material is not required,
and continuing the aforesaid pneumatic filling operation progressively in a given direction along said trench and removing said support pads seriatim as the filling operation approaches each said pad.

The method of backfilling a pipeline trench comprising the steps:

supporting a pipeline at a desired final position and grade within said trench at spaced intervals along said pipeline so as to create a substantial air space between said pipeline and the bottom of said trench except at such intervals and air spaces between the opposite sides of said pipeline and opposite sides of said trench,
blowing a granular fill material into said trench under pneumatic pressure first along the bottom of said trench below said pipeline and into the space between said pipeline and the bottom of said trench and then progressively upwardly along the opposite sides of said pipeline and trench to fill the spaces between said opposite sides of said pipeline and opposite sides of said trench and simultaneously compact said fill material to a substantially uniform desired final density about the bottom and opposite sides of said pipeline to thereby substantially eliminate air pockets within said fill material and between said fill material and said pipeline, and eliminate the need for subsequent compaction of such fill material,
and blowing said fill material in the aforesaid manner simultaneously from opposite sides of said pipeline so that said filling operation progresses simultaneously from beneath and below said pipeline upwardly along the opposite sides thereof.

Dependencies are inferred from the claim text.

Method of backfilling pipeline trenches

Life of this patent

Method of backfilling pipeline trenches

Life of this patent

Abstract

Claims12