<p>When blasting excavation is carried out near building pile foundations in urban tunnel projects, the pile-soil interface experiences damage under the blasting dynamic loading, leading to a reduction in interface strength. Based on a self-developed pile-soil interface shear testing device capable of applying dynamic disturbance loads, this study investigates the strength degradation behaviour of the pile-soil interface under dynamic disturbance loading, considering factors such as model pile roughness (0°, 15°, 30°), dynamic disturbance load intensity (Class A, Class B, Class C), and the number of dynamic disturbance cycles. The results show that the shear mechanical properties of smooth pile-soil interfaces exhibit strain softening, whereas those of rough pile-soil interfaces exhibit strain hardening. As the roughness of the model pile increases, the shear strength of the pile-soil interface increases, but the rate of growth in shear strength decreases. Under dynamic disturbance loading, the shear strength of the pile-soil interface decreases for all roughness conditions, and the shear strength continuously decreases with increasing dynamic load intensity. The stress wave at the pile-soil interface causes both transmission and reflection, inducing tensile-shear effects that generate microcracks and reduce interface strength. Under different dynamic disturbance load intensities applied to pile-soil interfaces with varying roughness, the microcracks generated by the transmission and reflection of stress waves at the pile-soil interface accumulate as the number of disturbance cycles increases, resulting in a continuous decrease in the shear strength of the interfaces with varying roughness. After 20 cycles of Class C dynamic loading, the shear strength attenuation of the pile-soil interface with 0° roughness, 15° roughness, and 30° roughness is 7.59% to 17.31%. The research results can guide the safety control of pile foundations in buildings adjacent to tunnel blasting.</p>