NUMERICAL ANALYSIS AFFECTING LOOSENING OF SURROUNDING SOIL CAUSED BY REMOVAL AND BACKFILLING OF EXISTING PILES ON PILE EXTRACTION METHOD WITH SHAFT-SOIL SEPARATION

In recent years, numerous buildings constructed during Japan’s period of rapid economic growth have undergone reconstruction or redevelopment. Consequently, the removal of existing piles and the restoration of ground conditions to their original state have become increasingly required. However, several cases have been reported in which the disturbance of the ground caused by pile removal has resulted in a reduction of soil strength. To elucidate this mechanism, a series of numerical analyses were conducted using the Subloading tij model. This decrease in mean effective stress is considered to be the primary factor contributing to the observed reduction of soil strength.