Treatment technology and application of bored-cast-in-place piles with defect at extreme depth by means of concrete pumping

After the defects of bored-cast-in-place piles at great depth are detected, the concrete around the defects is removed and then new concrete is filled by high-pressure pumping so as to keep the same quality as the original materials. This technology is originally employed in the defect treatment if an inter-layer is examined in bored-cast-in-place piles. For the Hangzhou Bay Bridge, defects are found around 63-67 m of the total length of 96 m in the bored-cast-in-place pile No.1 of the North Bridge for shipping through the ultrasound and CT measurements. After the application of this technology in the defect treatment of the pile, the pile capacity is effectively strengthened to keep the same quality as that of the original concrete compared with the commonly used concrete grouting.