Upgrading and Application of Small-sized Drilling Rig in the Protection of Transmission Tower near Deep Foundation Pit

Abstract

The small-sized drilling rig such as XY-100 is widely used in survey engineering. With the development of underpinning technique, more and more micro-pile should be drill near buildings and structures. The higher rig shelf should be upgraded for suit with limited space. The excavation of deep foundation pit lead to security risks when high voltage transmission tower near the pit. Based on the foundation underpinning technology and the deep foundation pit supporting method, a reinforcement design method is proposed for transmission tower foundation near deep excavation. In the method, the shallow foundation of tower is transformed into pile foundation firstly using micro-pile which transfer the loads to the deep soil layer. Then using micro pile composite soil nailing wall supporting technology to support for the vertical excavation of deep foundation pit. The micro-piles are drilled using the upgrading drill rig and the protection engineering achieved success.