Method for consolidating foundation soils or for lifting very heavy or very large structures requiring the application of a pressure of more than 500 kpa

Abstract

A method for consolidating foundation soils or for lifting very heavy or very large structures requiring the application of a pressure of more than 500 kPa, which consists in injecting into the soil to be consolidated or into the soil below the foundations of the structure to be lifted substances which expand as a consequence of a chemical reaction and are suitable to generate, during expansion, a pressure of more than 500 kPa.

1 - 16 . (canceled)  
   
   
       17 . A method for consolidating foundation soils or for lifting very heavy or very large structures requiring the application of a pressure of more than 500 kPa, comprising the step of injecting into the soil to be consolidated or into the soil below the foundations of the structure to be lifted substances which expand as a consequence of a chemical reaction and are suitable to generate, during expansion, a pressure of more than 500 kPa.  
   
   
       18 . A method for consolidating foundation soils or for lifting very heavy or very large structures requiring the application of a pressure of more than 500 kPa, comprising the steps of: 
 producing a plurality of holes in the soil, said holes being mutually spaced and lying below the lower front or underside of the foundations of the structure;    injecting into the soil, through said holes, a substance which expands as a consequence of a chemical reaction and comprises a mixture of polyols and an MDI isocyanate, or a similar expandable substance, with an expansion start time substantially between 2 and 25 seconds and with a potential volume increase, as a consequence of expansion, of more than 5 times the volume of the expandable substance before expansion;    determining when the intended degree of consolidation of the soil or the intended degree of lifting of the structure is reached;    ending the injection of said expandable substance when the intended degree of consolidation of the soil is reached or when the intended degree of lifting of the structure is reached.    
   
   
       19 . The method according to  claim 18 , wherein the intended degree of lifting of the structure and/or the intended degree of consolidation of the soil is determined by constantly monitoring the level of the structure above the injection region.  
   
   
       20 . The method according to  claim 18 , wherein the intended degree of consolidation of the soil is determined by measuring the amount of injected expandable substance.  
   
   
       21 . The method according to  claim 17 , wherein the expansion start time of said expandable substance is substantially between 2 and 7 seconds.  
   
   
       22 . The method according to  claim 17 , wherein said expandable substance, during expansion, generates a pressure on the surrounding soil that is proportional to the tension opposed by the soil and is higher than 500 kPa and can exceed 10,000 kPa.  
   
   
       23 . The method according to  claim 17 , wherein said expandable substance comprises two components: a first component constituted by polyether polyol and/or polyester polyol, by a catalyst and by water, and a second component constituted by MDI isocyanate.  
   
   
       24 . The method according to  claim 18 , wherein said holes are formed vertically.  
   
   
       25 . The method according to  claim 18 , wherein said holes are formed at an angle with respect to the vertical.  
   
   
       26 . The method according to  claim 18 , wherein the injection of said expandable substance in said holes is performed simultaneously in a plurality of holes.  
   
   
       27 . The method according to  claim 18 , wherein the injection of said expandable substance in said holes is performed continuously, making the injection point rise gradually along the corresponding hole.  
   
   
       28 . The method according to  claim 18 , wherein the injection of said expandable substance in said holes is performed in a plurality of steps, making the injection point rise intermittently along the corresponding hole.  
   
   
       29 . The method according to  claim 18 , comprising additional steps for the injection of said expandable substance in holes which are spaced between the holes already used for preceding injection steps.  
   
   
       30 . The method according to  claim 17 , wherein an expandable substance is used that comprises a mixture of polyols and an MDI isocyanate, or a similar expandable component, with an expansion start time substantially between 2 and 25 seconds and with a potential volume increase, as a consequence of expansion, which is more than five times the volume of the substance before expansion, in order to consolidate foundation soils or lift very heavy or very large structures that require the application of a pressure of more than 500 kPa.  
   
   
       31 . The method according to  claim 30 , wherein said expandable substance comprises a mixture of two components: a first component, constituted by polyether polyol and/or polyester polyol, by a catalyst and by water, and a second component, constituted by MDI isocyanate.  
   
   
       32 . The method according to  claim 31 , wherein said expandable substance has an expansion start time that is substantially between 2 and 7 seconds.