Abstract: Ultra-large mining height faces with multiple thick and hard strata (MTHS) exhibit highly complex overburden structural evolution, intense support loading, and frequent dynamic events, posing serious challenges to roof stability and safe, efficient mining. To clarify the mechanisms of overburden instability and strong ground pressure under MTHS conditions, the 122104 working face of the Caojiatan coal mine, the first 10 m ultra-large mining height face in China was selected as the engineering case. A combination of physical simulation, digital image correlation (DIC) monitoring, and field measurements was employed to investigate the evolution of overburden failure, deformation characteristics, and support shield resistance behavior. Based on the findings, a composite mechanical model of “fractured arch-long cantilever beam-articulated rock beam” was established to describe the overburden structural evolution and its control over ground pressure behavior. The results indicate that overburden failure evolves through three distinct stages. ① Progressive delamination, the immediate roof and lower hard strata undergo gradual separation, and the caving height approximates the delamination height. ② Sudden structural failure, the lower hard strata form a long cantilever beam that fractures abruptly under small deformation, inducing cooperative collapse of multiple upper layers. The caving height greatly exceeds the delamination height, signifying beam-dominated instability. ③ Synergistic collapse, upper and lower hard strata jointly bear load, forming an ultra-long cantilever beam whose critical failure triggers extensive coordinated collapse. DIC observations show that the principal strain prior to beam fracture is below 10⁻², indicating brittle failure under elastic deformation. Overburden movement drives variations in support shield resistance, and the two exhibit strong correspondence. During gradual caving, the resistance increases steadily without impact; when the long beam reaches its critical span and fails, the resistance rises sharply, generating intense dynamic impact. The coordinated action of multiple hard strata enlarges the beam span and bearing range, amplifying both static accumulation and dynamic response. Field monitoring revealed a pattern of “high static resistance accumulation-multi-stage dynamic surges-high-frequency periodic weighting”, with an average leg shortening of 693 mm and a 52.6% safety valve opening rate, consistent with model predictions. This study deepens the understanding of overburden instability and strong ground pressure mechanisms dominated by thick hard strata, providing theoretical and technical guidance for roof control and dynamic disaster prevention in ultra-large mining height faces.