Experimental study on 3D image of adjacent impact from shield tunnel excavation

Referring to the engineering background of the shield section of the Tsinghuayuan tunnel passing through the pile foundation of Beijing Metro Line 13 at a short distance, an experimental model was established, and the three-dimensional disturbance characteristics of adjacent pile foundations caused by shield construction in pebble strata were carried out. A total of 5 model piles (1#~5# piles) are arranged in the test model. Taking the 1# pile as an example, the three-dimensional influence characteristics of the shield tunneling process on the pile foundation are analyzed, and it is found that the additional bending moment is mainly generated in the stage from -0.5D to 0D between the cutter head and the pile foundation, and the maximum transverse bending moment is the maximum longitudinal bending moment. The additional axial force is mainly generated in the stage of -0.5D to 1.5D, the additional settlement of the pile top is mainly generated in the stage of -1D to 1D, and the additional bearing capacity of th