Apparatus and method for measuring supporting force of large diameter ferroconcrete piles

An apparatus for measuring a supporting force of ferroconcrete piles installed at a scene by means of a bi-directional front end oil pressure loading apparatus using a high pressure loading system, comprising:

• an upper disc having a predetermined thickness and diameter;
• a lower disc positioned below the upper disc;
• a high-pressure jack positioned between the upper disc and the lower disc;
• upper and lower displacement measuring rods coupled to the ferroconcrete piles and separated from the upper disc by a predetermined distance;
• an oil pressure jack displacement instrument coupled to a side of the high-pressure jack;
• an oil pump for supplying oil pressure to the high-pressure jack;
• and
• an oil pressure hose and a load and pressure adjuster for conveying the oil pressure supplied by the oil pump to the high-pressure jack.

An apparatus for measuring a supporting force of ferroconcrete piles installed at a scene by means of a bi-directional front end oil pressure loading apparatus using a high pressure loading system, comprising:

• an upper disc having a predetermined thickness and diameter;
• a lower disc positioned below the upper disc;
• an oil pressure jack positioned between the upper disc and the lower disc;
• upper and lower displacement measuring rods coupled to the ferroconcrete piles and separated from the upper disc by a predetermined distance;
• an oil pressure jack displacement instrument coupled to a side of the oil pressure jack;
• an oil pump for supplying oil pressure to the oil pressure jack;
• and
• an oil pressure hose for conveying the oil pressure supplied by the oil pump to the oil pressure jack.

An apparatus for measuring a supporting force of ferroconcrete piles installed at a scene by means of a bi-directional front end oil pressure loading apparatus using a high pressure loading system, comprising:

• upper and lower displacement measuring rod casings;
• an induction cover having a penetration hole formed therein, said induction cover being insertable into said upper and lower displacement measuring rod casings;
• upper and lower displacement measuring rods having a predetermined length and insertable into the penetration hole of the induction cover;
• a connection member insertable into an interior of the induction cover and having a penetration hole formed therein for use in coupling the connection member to the induction cover, the upper and lower displacement measuring rods being successively inserted into the penetration holes;
• and
• a supporting plate positioned at a top of the induction cover and having an insertion rod for sealing top ends of the upper and lower displacement measuring rods.

A supporting force measuring method for use in an apparatus for measuring a supporting force of ferroconcrete piles installed at a scene by means of a bi-directional front end oil pressure loading apparatus using a high pressure loading system, said method comprising the steps of:

• forming a hole in a ground, said hole having a predetermined size and depth;
• installing the apparatus for measuring the supporting force in the hole;
• providing a tremie tube into which the bi-directional front end oil pressure loading apparatus is inserted;
• pouring concrete into the tremie tube, the concrete being poured into penetration holes via a tremie induction tube positioned at a lower end of the tremie tube;
• driving the bi-directional front end oil pressure loading apparatus so that a high oil pressure cylinder is inflated when the concrete is recuperated;
• measuring a displacement at upper and lower side faces of the bi-directional front end oil pressure loading apparatus using a displacement measuring rod after inflation of the high oil pressure cylinder, and measuring abrasion of the ground contacted by the concrete;
• and
• preparing a load distribution chart using the measured abrasion.

A supporting force measuring method for use in an apparatus for measuring a supporting force of ferroconcrete piles installed at a scene by means of a bi-directional front end oil pressure loading apparatus using a high pressure loading system, said method comprising the steps of:

• (a) providing a load sensor coupled to upper and lower discs of the apparatus;
• (b) measuring values derived by the load sensor for each loading;
• (c) calculating a piles column face abrasion at a predetermined loading using the measured values from the load sensor;
• (d) deriving a distribution chart according to a depth;
• (e) calculating a size of the abrasion with respect to a same upward load as a sinking amount at a predetermined downward loading from the distribution chart;
• (f) successively calculating a total abrasion distribution chart by directionally converting abrasion distributions on the lower of the upper and lower discs after the abrasion distribution on the lower of the upper and lower discs with respect to the downward loading is combined with an abrasion distribution on the upper of the upper and lower discs with respect to an upward loading;
• (g) deriving an axis load distribution chart at a predetermined loading by addition of a component of a front end supporting force of piles derived in step (c);
• (h) repeatedly carrying out the steps (b) thru (g);
• and
• (i) completing derivation of the axis load distribution chart with regard to a representative loading step.