Design and monitoring of foundation pit support project for pile foundation underpinning of abutment of interchange bridges

Based on the engineering case of the foundation pit support of No. F26 abutment pile foundation underpinning project on the ramp of Huanghe Road Interchange Bridge on Zhongzhou Avenue in Zhengzhou City, a construction scheme combining the cut and cover method with the underground excavation is put forward, and the composite support of soil-nailing wall shotcrete anchors, borehole grouting and internal bracings is employed. The real-time data monitoring of supporting structures is carried out by means of the remote automatic monitoring and the manual monitoring. The results show that the supporting structures and the construction scheme are reasonable, and the deformations of the slope and the surrounding ground are effectively controlled, and the maximum vertical displacement and the maximum horizontal displacement are 12 and 13 mm, respectively, which are less than the control values. During the whole construction process, the traffics around and above the foundation pit are not affected. The data monitoring system provides a reference for the safe construction and makes the whole project be successfully completed.