Composite Construction Technology of Boring for End-bearing Pile in Spherical Weathered Boulders

Abstract:

In 403 section of Shenzhen metro Line 4, borehole should be completed for end-bearing pile in spherical weathered granite with high strength, anisotropy and large inclined angle, which was only 20m to nearby buildings, so rotary drilling was adopted for safety. Composite drilling technology of drag bit cutting drilling, button roller bit compacting and rectification by annular coring bit was adopted with wall protection by slurry reverse circulation.