Method for pile-driving

Abstract

A method for optimizing the driving of a pile into the ground by a pile-driving machine using a hammer ram; moving a block for driving the pile towards the end of the pile with an impact energy (W kin ); determining a kinetic variable (Q 1 ) of the impact, proportional to the kinetic energy of the block, when the block is moving towards the pile in the pile driving direction; determining the value of a kinetic variable (Q 3 ) of the return motion, proportional to the kinetic energy of the block, when returning, after an impact on the pile, in a direction opposite to the pile driving direction; calculating a kinetic variable ratio (Q 1 /Q 3 ); comparing (Q 1 /Q 3 ) with a predetermined target value (Q 1 /Q 3 tav ) for (Q 1 /Q 3 ), producing the shortest possible total pile driving time (t tot ); adjusting the impact energy (W kin ) of the next impact so (Q 1 /Q 3 ) of the next impact is changed towards (Q 1 /Q 3 tav ).

1 . A method for optimizing the driving of a pile ( 7 ), the method comprising:
 driving the pile ( 7 ) into the ground by a pile-driving machine comprising a hammer ram ( 1 ) to be placed against the pile ( 7 ) and a block ( 6 ) that is movable back and forth therein;   moving the block ( 6 ) applied for driving the pile ( 7 ) towards the end of the pile ( 7 ) with a given impact energy (W kin );   determining the value of a kinetic variable (Q 1 ) of the impact, proportional to the kinetic energy of the block ( 6 ) used for driving the pile, when the block ( 6 ) is moving towards the pile ( 7 ) in the pile driving direction;   determining the value of a kinetic variable (Q 3 ) of the return motion, proportional to the kinetic energy of the block ( 6 ), when the block ( 6 ) is returning, after an impact on the pile ( 7 ), in a direction opposite to the pile driving direction;   calculating a kinetic variable ratio (Q 1 /Q 3 ) by means of the determined kinetic variable (Q 1 ) of the impact and kinetic variable (Q 3 ) the return motion;   comparing the obtained kinetic variable ratio (Q 1 /Q 3 ) with a predetermined target value (Q 1 /Q 3   tav ) for the kinetic variable ratio (Q 1 /Q 3 ), producing the shortest possible total pile driving time (t rot ) for the pile ( 7 );   adjusting the impact energy (W kin ) of the next impact in such a way that the kinetic variable ratio (Q 1 /Q 3 ) determined by the kinetic variable (Q 1 ) of the impact and the kinetic variable (Q 3 ) of the return motion of the next impact will be changed towards the target value (Q 1 /Q 3   tav ).   
     
     
         2 . The method according to  claim 1 , wherein the impact energy (W kin ) of the next impact is determined by utilizing the impact energy (W kin ) used in the preceding impacts and the real kinetic variable ratio (Q 1 /Q 3 ) obtained by it. 
     
     
         3 . The method according to  claim 2 , wherein the value of the impact energy (W kin ) is increased if the real impact variable ratio (Q 1 /Q 3 ) of the preceding impact is higher than the target impact variable ratio (Q 1 /Q 3   tav ). 
     
     
         4 . The method according to  claim 2 , wherein the value of the impact energy (W kin ) is decreased if the real impact variable ratio (Q 1 /Q 3 ) of the preceding impact is lower than the target impact variable ratio (Q 1 /Q 3   tav ). 
     
     
         5 . The method according to  claim 1 , wherein the difference of the kinetic variable ratios, i.e. the deviation (Δ Q 1 /Q 3 ) in the kinetic variable ratio, is calculated from the kinetic variable ratio (Q 1 /Q 3 ) and the target kinetic variable ratio (Q 1 /Q 3   tav ). 
     
     
         6 . The method according to  claim 5 , wherein the deviation in the kinetic variable ratio (ΔQ 1 /Q 3 ) is minimized by adjusting the impact energy (W kin ) of the block ( 6 ). 
     
     
         7 . The method according to  claim 1 , wherein before starting the pile driving process, the target variable ratio (Q 1 /Q 3   tav ) is determined by calculating on the basis of the cross-sectional area, length, and type of the pile, and/or the soil properties, by optimizing the impact energy (W kin ) so that by impacts producing an equal advance, the pile ( 7 ) can be driven to the determined depth in a time (t tot ) as short as possible. 
     
     
         8 . The method according to  claim 1  wherein the target kinetic variable ratio (Q 1 /Q 3   tav ) is determined so that by impacts producing different advances, the pile ( 7 ) can be driven to the determined depth in a time (t tot ) as short as possible. 
     
     
         9 . The method according to  claim 1 , using the impact time (T 1 ) as the kinetic variable (Q 1 ) of the impact motion and the return motion time (T 3 ) as the kinetic variable (Q 3 ) of the return motion, as well as the motion time ratio (T 1 /T 3 ) determined on the basis of these. 
     
     
         10 . The method according to  claim 1 , using the impact velocity (V 1 ) as the kinetic variable (Q 1 ) of the impact motion and the return motion velocity (V 3 ) as the kinetic variable (Q 3 ) of the return motion, as well as the velocity ratio (V 1 /V 3 ) determined on the basis of these. 
     
     
         11 . The method according to  claim 1 , using the kinetic energy (W 1 ) of the impact motion as the kinetic variable (Q 1 ) of the impact motion and the kinetic energy (V 3 ) of the return motion as the kinetic variable (Q 3 ) of the return motion, as well as the velocity ratio (V 1 /V 3 ) determined on the basis of these.