Abstract: The risk factors affecting the safety of pylon foundation in the shield tunneling under tunnels are analyzed. A threedimensional finite element software was used to establish a continuous medium model to simulate the entire process of the shielded tunneling. The results of the surface settlement curve, accumulated settlement, differential settlement and the tilting angle of the foundation around the tower foundation during the shielded tunneling were calculated and the results were processed. The results were compared with the safety control standard values and the safety evaluation conclusions were proposed. The results show that: when the shallowburied independent foundation of the electricity tower is located in the main influence area of the tunnel settlement, the doubleline shield will induce the secondary disturbance to the foundation consequently.The surface settlement, the settlement at the center of the foundation and the differential settlement among the adjacent foundations all exceed the control value. The overall inclination of the tower exceeds the alarm value. The shielded tunneling construction poses a serious threat to the safety of the electricity tower, and the overall transformation of the tower is required.

Key words: shielded tunneling, underpass construction, tower foundation, construction safety assessment