Method, kit and system for injecting grout into a borehole, method of deploying a tube into a borehole for grout injection and leader for use in a grout injection system

Abstract

The system and method to inject grout into a borehole uses a leader comprising opposite fore and aft portions, a pressure-bearing member between the fore and aft portions, and a leader passage extending from a fore opening at the leader fore portion to an aft opening in the leader aft portion. A tube is attached to the leader and connected to the leader aft opening. The leader is inserted into the borehole with the fore portion first. An impelling fluid is injected in the borehole downstream of the pressure-bearing member and exteriorly of the tube, resulting in pressure being applied on the pressure-bearing member and the leader consequently advancing towards the borehole bottom end, the leader carrying the tube with it to deploy the tube in the borehole. Upstream fluid located in the borehole upstream of the pressure-bearing member is evacuated out of the borehole through the leader passage and the tube. The injection of the impelling fluid is stopped when the leader reaches a leader target position and grout is then injected in the borehole, gradually filling the borehole. The impelling fluid is evacuated from the borehole through the leader passage and the tube while the grout is injected.

1 . A method of injecting grout into a borehole, said borehole comprising a peripheral wall, an open end allowing access from outside said borehole into said borehole and a bottom end opposite said open end, said method comprising:
 providing a leader comprising opposite fore and aft portions, a pressure-bearing member between said fore and aft portions, and a leader passage extending from a fore opening at the leader fore portion to an aft opening in the leader aft portion;   providing a tube attached to said leader and connected to said leader aft opening;   inserting said leader into said borehole with said fore portion first, said borehole defining an upstream portion located upstream of said pressure-bearing member and a downstream portion located downstream of said pressure-bearing member;   allowing said tube to extend outside of said borehole and to slide into said borehole as it is deployed therein;   injecting an impelling fluid in said borehole downstream portion exteriorly of said tube resulting in pressure being applied on said pressure-bearing member and said leader consequently advancing towards said borehole bottom end, said leader carrying said tube with it to deploy said tube in said borehole; while upstream fluid located in said borehole upstream portion is evacuated out of said borehole through said leader passage and said tube;   stopping the injection of said impelling fluid when said leader reaches a leader target position;   injecting grout in said borehole downstream portion; and   evacuating said impelling fluid from said borehole through said leader passage and said tube while said grout is injected, including allowing said impelling fluid to flow from said borehole downstream portion to said borehole upstream portion.   
     
     
         2 . A method as defined in  claim 1 , further comprising:
 sealing said borehole open end before injecting said impelling fluid in said borehole downstream portion; and   providing a downstream fluid connection allowing access to said borehole downstream portion exteriorly of said tube from outside said borehole, with the step of injecting an impelling fluid in said borehole downstream portion being accomplished through said downstream fluid connection and with the step of injecting grout into said borehole downstream portion being accomplished through said downstream fluid connection.   
     
     
         3 . A method as defined in  claim 2 , wherein the step of allowing said grout to flow from said borehole downstream portion to said borehole upstream portion comprises disabling said pressure-bearing member. 
     
     
         4 . A method as defined in  claim 3 , wherein said pressure-bearing member comprises a leader main body and a leader seal attached to and located outwardly of said main body, said impelling fluid applying pressure against said leader seal to force said leader towards said borehole bottom end, said leader seal substantially sealing an area between said leader main body and the borehole peripheral wall, the step of disabling said pressure-bearing member comprising said leader seal rupturing when a threshold pressure is achieved in said borehole downstream portion. 
     
     
         5 . A method as defined in  claim 4 , wherein said leader target position corresponds to said borehole bottom end and said threshold pressure will be achieved when said leader reaches said borehole bottom end and is prevented from further advance while impelling fluid continues to be injected into said borehole downstream portion. 
     
     
         6 . A method as defined in  claim 2 , wherein the step of sealing said borehole open end is accomplished with a borehole interface member inserted in said open end, said borehole interface member comprising a plug that seals said borehole open end, an inner channel extending through said plug, and a tube seal sized to receive said tube therethrough, said tube seal preventing fluid to flow out of said borehole through said inner channel but allowing said tube to slide into said borehole through said tube seal and said inner channel. 
     
     
         7 . A method as defined in  claim 6 , wherein said downstream fluid connection is provided on said borehole interface member such that access to said borehole downstream portion is allowed through said borehole interface member inner channel exteriorly of said tube. 
     
     
         8 . A method as defined in  claim 5 , wherein stopping the injection of said impelling fluid when said leader reaches said leader target position is accomplished in either one of the following cases:
 if there is a marked increase in impelling fluid flow out of said borehole through said tube; and   if there is a marked increase of pressure in said borehole downstream portion.   
     
     
         9 . A method as defined in  claim 8 , further comprising the step of stopping the injection of said grout when grout overflows out of said borehole through said leader passage and said tube. 
     
     
         10 . A method as defined in  claim 2 , wherein said impelling fluid comprises water. 
     
     
         11 . A method of deploying a tube into a borehole for injecting grout, said borehole comprising an open end allowing access from outside said borehole into said borehole and a bottom end opposite said open end, said method comprising:
 providing a leader comprising opposite fore and aft portions, a pressure-bearing member between said fore and aft portions, and a leader passage extending from a fore opening in said leader fore portion to an aft opening in said leader aft portion;   providing a tube attached to said leader and connected to said leader aft opening;   inserting said leader into said borehole with said fore portion first, with said borehole defining an upstream portion located upstream of said pressure-bearing member and a downstream portion located downstream of said pressure-bearing member;   allowing said tube to extend outside of said borehole and to slide into said borehole as it is deployed therein;   injecting an impelling fluid in said borehole downstream portion exteriorly of said tube resulting in pressure being applied on said pressure-bearing member and said leader consequently advancing towards said borehole bottom end, said leader carrying said tube with it to deploy said tube in said borehole; while upstream fluid located in said borehole upstream portion is ejected out of said borehole at least partly through said leader passage and said tube; and   stopping the injection of said impelling fluid when said leader reaches a leader target position.   
     
     
         12 . A method as defined in  claim 11 , further comprising:
 sealing said borehole open end before injecting said impelling fluid in said borehole downstream portion; and   providing a downstream fluid connection allowing access to said borehole downstream portion exteriorly of said tube from outside said borehole, with the step of injecting an impelling fluid in said borehole downstream portion being accomplished through said downstream fluid connection.   
     
     
         13 . A method as defined in  claim 12 , wherein said impelling fluid is one of grout and water. 
     
     
         14 . A grout injection kit for use in assembling a grout injection system for injecting grout into a borehole, comprising:
 a leader comprising opposite fore and aft portions, a pressure-bearing member between said fore and aft portions, and a leader passage extending from a fore opening in said leader fore portion to an aft opening in said leader aft portion;   a tube attachable to said leader and connectable to said leader aft opening;   a borehole interface member comprising:
 a plug; 
 an inner channel extending through said plug and sized to allow said tube to loosely extend and slide therethrough; 
 a tube seal in said inner channel, sized to allow said tube to extend and slide therethrough while preventing fluid flow between said tube seal and said tube; and 
 a downstream fluid connection allowing fluid access into said inner channel exteriorly of said tube. 
   
     
     
         15 . A grout injection kit as defined in  claim 14 , further comprising a fluid pump connectable to said downstream fluid connection. 
     
     
         16 . A grout injection kit as defined in  claim 15 , further comprising an additional fluid pump connectable to said tube. 
     
     
         17 . A grout injection kit as defined in  claim 14 , wherein said pressure-bearing member comprises a leader seal designed to rupture at a determined pressure threshold. 
     
     
         18 . A grout injection system for injecting grout into a borehole, comprising:
 a leader comprising opposite fore and aft portions, a pressure-bearing member between said fore and aft portions, and a leader passage extending from a fore opening in said leader fore portion to an aft opening in said leader aft portion, said leader for insertion into said borehole with said fore portion first and said borehole thus defining an upstream portion located upstream of said pressure-bearing member and a downstream portion located downstream of said pressure-bearing member;   a tube attached to said leader and connected to said leader aft opening;   a plug for sealing the borehole;   a tube channel for allowing said tube to slidingly extend into said borehole from outside the borehole;   a downstream fluid connection for allowing fluid access into said borehole downstream portion exteriorly of said tube; and   a fluid pump connectable to said downstream fluid connection.   
     
     
         19 . A grout injection system as defined in  claim 18 , further comprising an additional fluid pump connectable to said tube. 
     
     
         20 . A grout injection system as defined in  claim 18 , wherein said leader comprises a main body and said pressure-bearing member comprises a leader seal attached to and located outwardly of said main body, said leader seal for substantially sealing an area between said leader main body and the borehole peripheral wall, said leader seal designed to rupture upon a threshold pressure being applied thereagainst. 
     
     
         21 . A grout injection system as defined in  claim 18 , further comprising a borehole interface member that carries said plug, said tube channel comprising an inner channel extending through said borehole interface member including through said plug, and said downstream fluid connection connects to said inner channel through said borehole interface member. 
     
     
         22 . A leader for use in a grout injection system, said leader comprising opposite fore and aft portions, a pressure-bearing member between said fore and aft portions, and a leader passage extending from a fore opening in said leader fore portion to an aft opening in said leader aft portion. 
     
     
         23 . A leader as defined in  claim 22 , further comprising a main body, said pressure-bearing member comprising a leader seal attached to and located outwardly of said main body, said leader seal designed to rupture upon a threshold pressure being applied thereagainst.