Influencing Factors Analysis of Stability of Hole Wall of Bored Pile in Seasonal Frozen Ground in the West of China

Collapsing and shrinkage of hole wall are two troubles to drilling of bored pile. In order to avoid such troubles, ultimate hole depth of bored pile was deduced with dry excavation technology. To hydraulic excavation technology, by the method of finite element numerical simulation and finite element strength reduction, excavation process of hole of bored pile are simulated in ADINA and ANSYS software, The influences of hole radius, hole depth, power of rotary drilling rig and pressure of auger boring tool on stability of hole wall are analyzed. The analysis indicate that the major problem of stability of hole wall of bored pile in seasonal frozen ground in the west of China is hole shrinkage. the deeper and bigger the hole are or the greater the pressure of auger boring tool is, the more serious the phenomenon of hole shrinkage is. Under other same conditions, to reduce pressure of auger boring tool less than to 35KPa, hole shrinkage can be reduced effectively.