Underground structures are important civil infrastructure in modern urban areas. They are used in a wide range of engineering applications including building foundations, underground transportation systems, and underground storage facilities. The stability of the excavated ground is a major challenge in the design and construction processes. Bracing approaches have been implemented in the current state-of-practice to ensure the safety of the excavation. One common braced excavation system involves vertical retaining walls on both sides of the excavated ground held in place using horizontal internal struts. These struts are designed using empirical lateral pressure distribution envelopes. A set of scaled physical models were designed and tested to evaluate these internal strut loads and compare them with empirically predicted values. The empirical equations predicted lower strut loads than what were measured experimentally. Several reasons could result in the difference, especially the fixity of the structure, construction process, and the depth of the model.
