Process For Exposing Underground Utilities

Abstract

A process for safely excavating to reveal underground utilities. The process includes the steps of: identifying known utilities; planning an excavation trench; excavating the trench by: (i) making a cut of the excavation trench at a selected depth; (ii) extracting material from the trench; (iii) observing the trench; (iv) adjusting the depth of cut; and repeating (i) to (iv) until the process is complete.

1 . A process for exposing underground utilities in an excavation zone which may contain known utilities and unknown utilities including the steps of:
 identifying known utilities;   planning an excavation trench taking into account known utilities;   excavating the trench by:
 (i) making a cut of the excavation trench at a selected depth; 
 (ii) extracting material from the trench; 
 (iii) observing the trench to identify signs of the presence of a utility; 
 (iv) adjusting the depth of cut based on the outcome of the observation such that the depth of cut is reduced at the first signs of the pressure of a utility and further reduced as the cut approaches the utility; and 
   repeating (i) to (iv) until the process is complete.   
     
     
         2 . The process of  claim 1  wherein the step of identifying known utilities includes one or more of: checking records of utility locations; tracing likely utility routes from known nodes; tracing utilities using ground penetrating radar or other subterranean mapping techniques. 
     
     
         3 . The process of  claim 1  wherein the step of planning the trench includes selecting a trench location to minimise disruption of known utilities. 
     
     
         4 . The process of  claim 1  wherein the step of planning the trench includes marking the selected trench location on the ground together with known utility locations and depth. 
     
     
         5 . The process of  claim 4  wherein the marking of known utility locations and depths are colour coded to maximise visibility. 
     
     
         6 . The process of  claim 1  wherein the step of a making a cut of the excavation trench is performed by a mechanical saw that has controllable depth of cut. 
     
     
         7 . The process of  claim 6  wherein the first cut of a new trench is at a depth of 50 mm or 45 mm or 40 mm or 35 mm or 30 mm or 25 mm or 20 mm or 15 mm or 10 mm or 5 mm. 
     
     
         8 . The process of  claim 6  wherein a location of the mechanical saw is controllable in the X direction (advancement along the trench), Y direction (lateral position of the cut) and Z direction (depth of cut). 
     
     
         9 . The process of  claim 1  wherein the step of extracting material from the trench uses a vacuum excavation machine. 
     
     
         10 . The process of  claim 9  wherein the step of extracting material from the trench uses a vacuum excavation machine and the vacuum excavation machine follows closely behind the mechanical saw to continuously remove material from the trench. 
     
     
         11 . The process of  claim 9  wherein the vacuum excavation machine is a hydro excavator that can operate in a low pressure mode of about 200 psi and a high pressure mode of about 2000 psi. 
     
     
         12 . The process of  claim 1  wherein the step of observing the trench includes observing the bottom and/or sides of the trench to identify any sign of the presence of a utility. 
     
     
         13 . The process of  claim 12  wherein the signs include one or more of: change in colour; change in material; cracking, pitting or lifting. 
     
     
         14 . The process of  claim 1  wherein the step of adjusting the depth of cut is based on the observation of the trench. 
     
     
         15 . The process of  claim 14  wherein the adjustment to the depth of cut is 0 mm.