Abstract: This paper presents a case history of mitigating the horizontal cracks in the manually dug caissons. The horizontal cracks are detected by the low strain integrity tests and concrete coring methods. High pressure grouting was used to seal off these defects. The construction techniques of minimizing the horizontal cracks in the manually dug caissons are also proposed.

Key words: Manually Dug Caissons, Horizontal Cracks, Low Strain Integrity Testing Methods, High Pressure Grouting