APPLICATION OF UNDERPINNING PILE BY MANUAL DIGGING IN TREATMENT OF COLLAPSIBLE LOESS FOUNDATION ACCIDENT

A single story industrial building in Xi'an is positioned on a high-filled ground. Because the designeradopted unsuitable ground treatment method，so cracks occurred on the wall and the floor，whose width was about 2.0centimeter inside and outside of the ground which were nearly SN direction; the extensional fracture was mainly on the west of building， which was a serious hidden danger of the building. The scheme of rectifying deviation by underpinning pile was employed after investigation for sake of safety. Based on which the following aspects were investigated: the formula to determine the numbers of underpinning piles for rectifying the leaning building was presented; scheme choice of rectifying deviation，designing method，construction procedure of underpinning pile，jacking monitoring and controlling were introduced in derail; difficult factors and corresponding problems during jacking construction were provided. After reinforcement construction， the settlement of the building tended to stabilization and the normal operation of the workshop was restored. After deformation observation for 6 months，it can be concluded that underpinning pile by manual digging is feasible to reinforce similar structures and project in loess region.