Abstract: When a 10 m-deep foundation site in thick soft silty peaty soils in Wuhan was excavated to the second internal cross supporting layer, an excavator was overturned and seriously damaged the concrete supporting beam. To mitigate this accident, the excavated area was backfilled so that the horizontal displacement and the internal force in the supporting beans were effectively controlled. But the support beam was seriously damaged, the balance of the support system was destroyed. The remediation work was performed on the support beams and nodes were reinforced in a timely manner. The following excavation was performed safely. This paper introduces the project overview, accident cause and remediation plan and site monitoring program. Deep excavation construction accidents are relatively common, according to different conditions of the effective remediation program selected is also valuable engineering experience.