Local Stability of End-suspended Piles in Ultra-deep Foundation Pits
At present,the reserved rock shoulder width of end-suspended piles and the embedded depth of support piles in foundation pits are mostly determined from the impact on internal forces and deformations of the upper sup-port structure.This approach often overlooks the local stability issues near the bottom of the support structure.Based on the ultra-deep shaft project of the Pearl River Delta Water Resources Allocation Project,we identified three po-tential failure modes for end-suspended pile foundation pits with inclined structural planes or fractured rock masses.We employed the limit equilibrium method to calculate the stability safety factor and analyze the impact of various parameters on the safety factor under different failure modes,such as rock layer burial depth,mechanical properties of structural planes,rock shoulder width,and rock shoulder depth.Our findings reveal that the inclination angle of outward-dipping structural planes and the mechanical properties of structural planes or rock masses significantly af-fect the stability safety factor.This study offers valuable insights for similar projects.
deep foundation pitvertical shaftend-suspended pilestructural planelimit equilibrium methodsafety factor