Shadowing pathology on diaphragm walls investigation

Nowadays, the densification of cities requires the multiplication of underground infrastructures like car parks and metro stations. It is in this context that has been established for 70 years now, the diaphragm wall technique. The construction works follow complex implementation operations that can generate some defects and cause the appearance of imperfections. Among these imperfections, shadowing pathologies is the main subject of this study. The objective is to better understand the different operations with the intention in explaining the formation of the pathology. An experimental study is presented to answer some questions related to the concrete. Thanks to a laboratory prototype called Beta Tank, two complementary campaigns were conducted. Using different exfiltration outcomes, and by varying the cementitious material, it was possible to recreate the shadowing pathologies. The results found from the experimental campaigns allowed identifying potential causes of the anomalies and helped in proposing some recommendations for the foundation materials and techniques.