[On-site Trouble Case] The test water tank sank when the steel arrow board was pulled out.

Learning from cases where steel arrows could not be removed: estimated causes and proposed countermeasures!

This is a case where the test water tank sank after pulling out the temporary soil retaining steel sheet pile for the water tank structure work, and the steel sheet pile could not be removed. When the steel sheet pile was pulled out at the end of the temporary period, the viscous soil adhered to it and was pulled up together. As a result, a void of the size of the steel sheet pile plus additional material occurred within the ground. The surrounding ground moved into the void that formed within the ground, and it is estimated that the water tank structure also sank into the void, causing the tank to sink. 【Countermeasure Proposal】 ■ Apply a friction reduction agent (friction cutter agent) to the temporary steel sheet pile in advance to prevent adhesion between the temporary steel sheet pile and the ground soil, thereby minimizing the ground voids that occur during the pulling out of the steel sheet pile. *For more details, please download the PDF or feel free to contact us.

Piles, caissons, sheet pilesGround foundation construction method