System and method for mitigation of liquefaction

Abstract

A method for the reduction of liquefaction potential within soil of a stratum located a distance deep below a foundation of a structure through the injection of a two-part polyurethane liquid forming a polymer foam.

What is claimed is: 
     
         1 . A system for reinforcing a soil stratum with increased liquefaction potential, comprising:
 a plurality of injectors, one or more injectors comprising:
 a proximal portion having a hollow shape and a solid outer wall, the proximal portion having a length to span from a ground surface to the soil stratum, and 
 a distal portion having a hollow shape and a perforated outer wall; 
   one or more injection nozzles configured to couple with one or more of the plurality of injectors;   wherein, in use, the plurality of injectors are inserted within the soil stratum and an injection fluid is pumped from the one or more injection nozzles into the soil stratum through the plurality of injectors, the injection fluid exits the perforated outer wall of the distal portions of the plurality of injectors, and the injection fluid hardens to displace water from within the soil stratum.   
     
     
         2 . The system of  claim 1 , wherein the one or more injectors comprising:
 a drill cap coupled to an end of the distal portion, wherein, in use, the injection fluid forces off the drill cap from the end of the distal portion to provide another opening for injection of the injection fluid.   
     
     
         3 . The system of  claim 1 , wherein the proximal portion or the distal portion of the one or more injectors comprises two or more segments connected together to form the one or more injectors having a length configured to allow at least a portion of the distal portion to extend into a loose stratum of the soil stratum. 
     
     
         4 . The system of  claim 1 , wherein the proximal portion or the distal portion of the one or more injectors has a tapered shape from a first end to a second end. 
     
     
         5 . The system of  claim 1 , wherein the perforated outer wall of the one or more injectors comprises a plurality of openings, the plurality of openings being covered by a plurality of corresponding covers when the one or more injectors are inserted into the soil stratum, and the plurality of covers being configured to open the corresponding opening in the perforated outer wall when sufficient pressure is applied by the injection fluid when exiting the perforated outer wall through the plurality of openings. 
     
     
         6 . The system of  claim 1 , wherein the distal portion has a distal portion length generally corresponding to the thickness of a loose stratum of the soil stratum. 
     
     
         7 . An injector for reinforcing a soil stratum with increased liquefaction potential, comprising:
 a proximal portion having a hollow shape and a solid outer wall, the proximal portion having a length to span from a ground surface to the soil stratum, and   a distal portion having a hollow shape and a perforated outer wall; and   an injection nozzle configured to couple with the injector;   wherein, in use, the injector is inserted within the soil stratum and an injection fluid is pumped from the injection nozzle into the soil stratum through the injector, the injection fluid exits the perforated outer wall of the distal portion the injector, and the injection fluid hardens to displace water from within the soil stratum.   
     
     
         8 . The injector of  claim 7 , further comprising:
 a drill cap coupled to an end of the distal portion, wherein, in us, the injection fluid forces off the drill cap from the end of the distal portion to provide another opening for injection of the injection fluid.   
     
     
         9 . The injector of  claim 7 , wherein the proximal portion or the distal portion of the injector comprises two or more segments connected together to form the injector having a length configured to allow at least a portion of the distal portion to extend into a loose stratum of the soil stratum. 
     
     
         10 . The injector of  claim 7 , wherein the proximal portion or the distal portion of the one or more injectors has a tapered shape from a first end to a second end. 
     
     
         11 . The injector of  claim 7 , wherein the perforated outer wall of the injector comprises a plurality of openings, the plurality of openings being covered by a plurality of corresponding covers when the one or more injectors are inserted into the soil stratum, and the plurality of covers being configured to open the corresponding opening in the perforated outer wall when sufficient pressure is applied by the injection fluid when exiting the perforated outer wall through the plurality of openings. 
     
     
         12 . The system of  claim 7 , wherein the distal portion has a length generally corresponding to the thickness of a loose stratum of the soil stratum. 
     
     
         13 . A method for the reduction of liquefaction potential within soil of a soil stratum located below a foundation of a structure, comprising:
 providing a plurality of injectors, one or more injectors of the plurality of injectors having a hollow shape over a proximal portion and a distal portion, the proximal portion having a solid outer wall, the distal portion having a perforated outer wall and a length for at least partially extending the distal portion into the soil stratum;   locating at least the portion of the distal portion of the one or more injectors within the soil stratum;   injecting injection liquid into the plurality of injectors and into the soil stratum via the perforated outer wall of the distal portion;   permeating the soil stratum with the injection liquid for displacing water and binding to the soil within the soil stratum; and   allowing the injection liquid to form a solid foam matrix comprising particles of the soil within the soil stratum.   
     
     
         14 . The method of  claim 13 , wherein the one or more injectors comprise a drill cap coupled to an end of the distal portion, and wherein the method further comprises:
 Forcing off the drill cap from the end of the distal portion using the injection liquid to provide another opening for injection of the injection fluid.   
     
     
         15 . The method of  claim 13 , wherein the proximal portion or the distal portion of the one or more injectors comprises two or more segments connected together to form the one or more injectors having the length, and wherein the method comprises:
 assembling the two or more segments of the proximal portion or the distal portion to form the one or more injectors.   
     
     
         16 . The method of  claim 13 , wherein the proximal portion or the distal portion of the one or more injectors has a tapered shape from a first end to a second end. 
     
     
         17 . The method of  claim 13 , wherein the perforated outer wall of the one or more injectors comprises a plurality of openings, the plurality of openings being covered by a plurality of corresponding covers when the one or more injectors are inserted into the soil, and wherein the method further comprises:
 opening the plurality of covers in the perforated outer wall when sufficient pressure is applied by the injection fluid when exiting the perforated outer wall through the plurality of openings.   
     
     
         18 . The method of  claim 13 , wherein the distal portion has a distal portion length generally corresponding to the thickness of a loose stratum of the soil stratum. 
     
     
         19 . The method of  claim 13 , wherein a loose stratum of the soil stratum comprises at least loose sand. 
     
     
         20 . The method of  claim 19 , wherein the loose sand is a first soil stratum, and the soil stratum comprises a second soil stratum disposed above the loose sand, the second soil stratum comprising sand having a higher density than the loose send in the first soil stratum.