METHOD FOR INCREASING STRENGTH OF EXISTING STEEL PIPE PILE

• Main Authors: WAKITA EIJI, TAKAHASHI IKUO, YOKOYAMA KAZUTOMO, KISHIDA SATORU, MANO HIDEYUKI, ISHII KIYOSHI, OGISAKO EIJI, SHIMAZAKI YASUYOSHI, MURAKAMI KAZUO, ONOE ATSUO, YOSHIDA SHIGERU, KATSUSAWA KATSUE, YOSHIDA JUN, FUKUTAKE TAKEYOSHI
• Format: Patent
• Language: English
• Published: 04.03.1997
• Edition: 6
• Subjects: EMBANKMENTS; EXCAVATIONS; FIXED CONSTRUCTIONS; FOUNDATIONS; HYDRAULIC ENGINEERING; SOIL SHIFTING; UNDERGROUND OR UNDERWATER STRUCTURES

PROBLEM TO BE SOLVED: To increase the strength of an existing steel pipe pile driven into the ground by digging the inside of the existing steel pipe pile, forming an increased-diameter space at the lower end by digging and pouring concrete into the existing steel pipe pile and the increased-diameter space. SOLUTION: Using a reverse circulation drill, the inside of an existing steel pipe pile 10 is dug up to the lower end of the pile 10, and then a water-jet cutter is inserted into the pile 10 to cut the lower end of the pile 10, with this cut piece pulled up through the inside of the pile 10. Then the reverse circulation drill is inserted again into the pile 10 and rotated in the direction opposite to the direction of excavation of the reverse circulation drill to form an increaseddiameter space S1 whose diameter is made larger than the outside diameter of the pile 10. Next, a reinforcement unit 12 is installed on the bottom surface of the increased-diameter space S1, and concrete 14 is placed using a tremie. A bottom 14a larger than the diameter of the pile 10 can be formed within the supporting ground 3, and the area of the supporting ground 3 to support vertical loads can be increased.