Experimental Investigation on Deformation Characteristics of Strutted U-Shape Sheet Pile Flexible Retaining Structures in Excavations Using 3D Printing

U-shape steel sheet piles are widely used in deep and large excavation engineering due to their excellent soil-retaining and water-stopping performances. To achieve deformation control in excavations, an experimental investigation on the deformation characteristics of a strutted U-shape sheet pile flexible retaining structure was conducted. Single-layer and double-layer strutted retaining structure excavation indoor model tests in sand, where U-shape sheet piles were formed by 3D printing, were successfully accomplished. Deformation was monitored in real time during the test. The results show that the lateral displacement mode of the retaining structure transformed with the change in excavation from the “cantilever” to the “bulge” and finally developed into an intricate “recurve bow”. The average maximum lateral displacement was 0.756% of the excavation depth. With a maximum settlement of 0.375% of the excavation depth on average, the distribution of ground settlement behind walls changed from “exponential” to “triangular” before ultimately transforming into “trough” or “trapezoid” mode. The maximum settlement to maximum lateral displacement ratio (smax/δmax) on average was 0.54; the maximum settlement deformation rate was always less than the maximum lateral displacement deformation rate.