System And Method For Subgrade Stabilization Of Railroad Bed

Abstract

The invention is a system and method for repairing, improving, and stabilizing subgrade and subsoil/natural ground layers of a rail bed generally consisting of softer soils. One embodiment includes a method of installing subsurface inclusions and ballast fills comprising injected slurry mixtures of stabilizing material such as cement grout mixed with in situ soil. Another embodiment includes a system of installed ground inclusions and ballast fills. Another embodiment includes an integrated system of equipment for emplacing the system of inclusions and ballast fills.

1 . A system for repairing a rail bed underlying a railroad having rails and cross ties, the system comprising:
 a rail mounted wheeled vehicle enabling the vehicle to be driven off and driven onto the rails;   a drill mast mounted on the vehicle, the drill mast having a pair of drills and corresponding drill heads;   a power source for powering the drills to selectively penetrate the rail bed; a pump;   a hydraulic lift mounted to the vehicle for rotating the drill mast between a first horizontal stowed position to a second vertical operating position;   a grout source wherein the pump operates to transfer the grout through a transfer line to the drill mast; and   wherein the drill heads inject the grout into the rail bed.   
     
     
         2 . The system, as claimed in  claim 1 , further comprising:
 a cement silo for storing grout material; and   a transfer line connected between the silo and pump enabling transfer of grout material from the silo to the pump.   
     
     
         3 . The system, as claimed in  claim 2 , further comprising:
 a rail trailer mounted on the rail ties and supporting the cement silo.   
     
     
         4 . The system, as claimed in  claim 3 , further comprising:
 an engine mounted on the rail trailer; and   drive tracks mounted on the rail tracks and communicating with the engine to propel the trailer.   
     
     
         5 . The system, as claimed in  claim 1 , wherein:
 the drill mast is secured to the truck by a support frame.   
     
     
         6 . The system, as claimed in  claim 1 , wherein:
 the vehicle further includes rail guides removably secured to the vehicle to maintain alignment of the wheels on the rail track.   
     
     
         7 . The system, as claimed in  claim 1 , wherein:
 the drill heads are selectively and controllably lowered to drill holes in the rail bed and are subsequently lifted to inject grout to form inclusions in the drilled holes.   
     
     
         8 . The system, as claimed in  claim 1 , wherein:
 the vehicle is operated to incrementally advanced to position the drills to emplace a plurality of inclusions that are spaced from one another along a length of the rail bed.   
     
     
         9 . A method for stabilizing subgrade and subsoil ground layers of a railroad bed underlying a railroad having rails and cross ties, the method comprising:
 providing a rail mounted vehicle, a drill mast mounted on the vehicle, the drill mast having a pair of drills and corresponding drill heads;   determining a location on the railroad where the subgrade or subsoil have failed causing destabilization of the ballast upon which the rails and cross ties lie;   positioning the drills over the location to a first position;
 drilling first holes by the drills into the subgrade and/or the subsoil; 
   withdrawing the drills and injecting a grout mix by the drill heads as the drills are withdrawn to form corresponding first inclusions in the first drilled holes;   moving the vehicle and repositioning the drills over the location to a second position spaced from the first position;   drilling second holes by the drills;   withdrawing the drills and injecting the grout mix by the drill heads as the drills are withdrawn to form corresponding second inclusions in the second drilled holes; and   wherein the vehicle and drill mast remain mounted on the railroad during emplacement of the inclusions.   
     
     
         10 . The method, as claimed in  claim 9 , further comprising:
 injecting the grout mix in a ballast pocket to fill the ballast pocket forming ballast fill that communicates with at least one inclusion.   
     
     
         11 . The method, as claimed in  claim 9 , further comprising:
 varying a rate of injection of the grout mix through the drills to selectively form the inclusions considering a volume of the drilled holes.   
     
     
         12 . The method, as claimed in  claim 11 , further comprising:
 varying a rate of injection of the grout mix through the drills to selectively form the ballast fill considering a volume of the ballast pocket.   
     
     
         13 . The method, as claimed in  claim 9 , further comprising:
 determining a scope of the failed subgrade and/or subsoil;   determining a number of inclusions required to repair the subgrade and/or subsoil;   predetermining an array of inclusions to emplace considering the number of inclusions required; and   sequentially emplacing the array of inclusions including a plurality of the inclusions that are spaced along a length of the railroad and spaced laterally from one another.   
     
     
         14 . The method, as claimed in  claim 13 , wherein:
 the array comprises a preselected number of rows of inclusions and a preselected lateral spacing of the inclusions in the rows.   
     
     
         15 . The method, as claimed in  claim 14 , wherein:
 the rows include at least two rows of inclusions extending along a length of the railroad.   
     
     
         16 . The method, as claimed in  claim 14 , wherein:
 the lateral spacing of the inclusions includes at least one of a pair of laterally aligned inclusions located on interior sides of corresponding rail tracks.   
     
     
         17 . The method, as claimed in  claim 16 , wherein:
 the lateral spacing of the inclusions includes at least one of a pair of laterally aligned inclusions located on exterior sides of corresponding rail tracks.   
     
     
         18 . The method, as claimed in  claim 16 , wherein:
 the lateral spacing of the inclusions includes at least three laterally aligned inclusions.   
     
     
         19 . The method, as claimed in  claim 9 , further comprising:
 rotating the drill mast from a first stowed position to a second vertical operating position for drilling the holes.   
     
     
         20 . The method, as claimed in  claim 9 , further comprising:
 selectively changing a lateral spacing of the drills on the drill mast to match a desired lateral spacing of inclusions to be formed.