Abstract: Aiming at the difficulty of deformation observation of adjacent pile foundation during excavation of ultra-large diameter tunnels, a transparent soil test scheme was proposed for ultra-large diameter tunnels going through pile foundation laterally.Fused quartz sand, as well as mixed solution of n-Dodecane and white oil were used as pore solution to prepare transparent soil, and optical observation system and PIV processing system were combined.The soil displacement around pile caused by shield tunnel excavation was analyzed and the soil displacement fields around pile under different conditions were obtained.The test results show that with the increase of the distance between piles and tunnels, the excavation disturbance to the soil near the pile foundation will become smaller and smaller.When the distance between piles and tunnels reaches 1.5 times the tunnel diameter, the influence on the pile foundation will reach the critical value.With the increase of pile length, the vertical displacement of soil on the pile side shows a parabolic form, first increasing and then decreasing.With the increase of pile length, the horizontal displacement of soil on the side of pile will change from soil of upper pile part leaning towards tunnel to soil of upper pile part together with soil of tunnel side all leaning towards tunnel.The closer the excavation face is to the pile foundation, the more severe the influence of excavation on the soil displacement around the pile.