Lateral bending Behavior and Calculation of Perforated Cross-Plate Joints in Lattice-Shaped Diaphragm Walls

Ke Li¹RUI YANG^1*Weicheng Tu¹Qinxin Hu²Qian Kong¹

• ¹CCCC Second Harbor Engineering Co., Ltd., Wuhan, China
• ²University of Strathclyde, Glasgow, United Kingdom

Due to their substantial vertical and horizontal bearing capacities, lattice-shaped diaphragm walls (LSDWs) have been increasingly employed in bridge foundations and foundation pit enclosure structures. In contrast to conventional diaphragm walls, which primarily bear vertical loads, LSDWs are mainly subjected to horizontal forces during foundation pit excavation. Therefore, it is essential to investigate the lateral bending performance of LSDW joints. This study investigates China's innovative LSDW ship lock wall project, offering the first comprehensive analysis of the lateral bending behavior of single-and double-cross perforated cross-plate joints (PCPJs). These joints represent a crucial yet insufficiently explored joint type within LSDWs. Eight sets of PCPJs and one non-joint wall were subjected to four-point bending tests to evaluate the 2 influence of the steel plate perforation ratio on the load-displacement response and bearing capacity of PCPJs. The investigation identified the typical lateral bending failure modes and mechanisms of PCPJs and proposed a method for calculating their lateral bending bearing capacity. The results reveal that the separation of the steel-concrete interface between the web plate and the lower flange, fracture of the concrete dowel, and tensile cracking of the concrete at the end of the steel plate flange characterize the lateral bending failure modes of PCPJs. The bending capacities of the single-and double-cross PCPJs in the elastic stage were 25.5% and 44.9% of the ultimate bearing capacity, respectively. Notably, the lateral bending capacity of the double-cross PCPJ segment was greater than that of the single-cross case but lower than that of the non-joint segment. Under the same perforation ratio, the lateral bending capacity of the double-cross PCPJ case was about 1.6 times greater than that of the single-cross case. Moreover, the lateral bearing capacity of the PCPJs was positively correlated with the perforation ratio. Compared with the single-cross PCPJ, the lateral bending bearing capacity of the double-cross PCPJ exhibited greater sensitivity to the perforation ratio. Additionally, the deviation between the calculated and experimental values ranged from –2.16% to 6.20%, validating the reliability of the proposed calculation method and providing a critical reference for similar engineering applications.