1. CASE JEILL ENTERPRISE CO., LTD. KOREA.

2. ( VIEW OF JOB SITE-01 )

3. ( VIEW OF JOB SITE-02 )

4. ( VIEW OF JOB SITE-03 )

5. 1. BACK GROUND ONE OF OUR CLIENTS ( CHOSUK CONSTRUCTION CO.) WHO IS A SUBCONTRACTOR SPECIALIZED IN JET GROUTING WORKS. THEY WERE SUBCONTRACTED GROUTING WORKS IN SUBSOIL LAYER UNDERNEATH EXISTING RUBBLE MOUND SITUATED 10 METERS BELOW SEA LEVEL AT A PORT PROJECT IN SOUTHERN KOREA. WORKS COMPRISED OF DRILLING 10 METERS RUBBLE MOUND, AND JET GROUTING 5-6 METERS THICK SILTY CLAY LAYER FOR THE PREVENTION OF SETTLEMENT AND IMPROVING BEARING CAPACITY. BIG CHALLENGE OF THE WORKS WAS LIMITED COMPLETION TIME, 60DAYS ALLOWED. THEY ESTIMATED CONSTRUCTION TIME WOULD BE 125 DAYS IF THEY ADOPTED AIR HAMMERS, IT WAS ABSOLUTELY UNACCEPTABLE.

6. IN ORDER TO SOLVE THESE PROBLEMS, WE RECOMMENDED THE CLIENT TO CHANGE DRILLING METHODS FROM AIR-POWERED DRILLING TO WATER-POWERED DRILLING. COMPARISION AIR DRILLING WATER DRILLING TOTAL DRILL METERS : 8,100 M 8,100 M PENETRATION RATE : 8.0 M/HR 25.0 M/HR TIME TO COMPLETE : 125 DAYS 40 DAYS

7. SCENE-HARBOR-KWANGYANG

8. 2. DETAILS OF PROJECT (A) PROJECT NAME : QUAYWALL CONSTRUCTION (B) JOB SITE LOCATION : SOUTHERN COAST IN KOREA (C) PROJECT PERIOD : 2008. 01 ~ 2008. 08 (D) QUAYWALL DIMENSION : LENGTH : 1,000 m WIDTH : 15 m ~ 20 m DEPTH : 15 m ~ 20 m (E) SCOPE OF WORKS : DRILLING WORKS FOR JET-GROUTING STEEL STRUCTURE WORKS CEMENT CONCRETE WORKS

9. DEPT H SEA LEVEL 15 m 5 m 10 m 20 m 25 m SEA WATER BOULDER SILTY CLAY BED ROCK 3. SOIL CONDITION

13. 4. JET-GROUTING WORKS FOR SOIL STABILIZATION (A) DRILLING WORKS HOLE Q’TY : 540 HOLE DIA. : 89.0 mm HOLE DEPTH : AVERAGE 15.0 m (B) CEMENT MILK INJECTION WORK CEMENT /WATER RATIO = 1 : 1 INJECTION PRESSURE : 400 bar INJECTION VOLUME : 180 Liter / Min INJECTION INTERVAL : 16 Min / m COLUMN DIA. : 2000 – 2500 m/m

14. SCENE – BRIDGE-PUSAN

15. 5. CONVENTIONAL METHOD (DRILLING) MACHINES APPLIED : DRILLING RIG MODEL : SM400 MFGR : SOILMEC S.P.A., ITALY TORQUE : 1198 daNm WEIGHT : 11 TON AIR COMPRESSOR MODEL : SULLAIR AIR PRESSURE : 21.0 KG/CM 2 HAMMER TYPE : DTH ( DOWN THE HOLE) OPERATION : PNEUMATIC POWER (AIR) DIA. : 4 “

16. 6. PROBLEMS WITH CONVENTIONAL METHOD - IMPACT POWER LOSS FROM WATER INSIDE. - LOW PENETRATION RATE ( 8.0 m / PER ONE HOUR ) - TOO MUCH DRILLING TIME REQUIRED. ( THREE HOURS OR MORE REQUIRED FOR 25-30 m DEPTH HOLE ) - DELAY THE WORK SCHEDULE. ( SCHEDULED PERIOD 60 DAYS, ESTMATED COMPLETE 125 DAYS ) - HIGHER CONSTRUCTION COST.

17. SCENE-SEASHORE- KWANGYANG

18. 7. IMPROVED METHOD BY WASSARA WATER HAMMER MACHINE APPLIED. - DRILLING RIGS : SM400 ( SAME AS CONVENTIONAL METHOD ) - HIGH PRESSURE PUMP : MODEL : 5T302 MFGR : SOILMEC S.P.A. ITALY PRESSURE : 400 bar DELIVERY : 250 Liter / Min. - HAMMER : TYPE : WATER HAMMER MODEL : W-100 HOLE DIA. : 115 mm (BIT) PRESSURE : 180 bar

19. 8. ADVANTAGES BY WASSARA WATER HAMMER - HIGHER IMPACT POWER. - HIGHER PENETRATION RATE. ( DRILLING SPEED 25-30 m / PER HOUR) - SHORTEN DRILLING TIME - IMPROVE WORK PROGRESS. - COST REDUCTION.

20. 9. CONSIDERATION FOR APPLICATION RECOMMEND FOR DRILLING : - UNDER WATER-LEVEL. - THROUGH BOULDER LAYER AND FRACTURED ZONE. - THROUGH ROCK STRATA. - BETTER TO CHOOSE THE COMPANIES WHO ALREADY HAVE HIGH PRESSURE PUMP. - EMPHASIZING REDUCTION OF DRILLING COST AND - HIGH DRILLING SPEED/SHORTEN DRILLING TIME.

21. ( BIRD’S –EYE VIEW AFTER COMPLETION )