Structural Characteristics and Deformation Evolution of an Intra-Continental Fold-Thrust Belt in Eastern Sichuan: Insights Into Analogue Sandbox Models

The Eastern Sichuan area is a typical fold-and-impulse zone. It bounded by the Qiyue Mountain fault, with septal folds on east and west. Based previous geological mapping surface structure research as well fault-related folding theory, in this study, tectonophysical simulation experiments were conducted to investigate tectonic geometry kinematics of fold-impulse selecting different experimental materials changing physical properties cover, friction between cover basement, number slip layers, burial depth, other factors. Finally, similarity results morphological characteristics real was assessed. show that deformation style influenced some extent brittle shear strength ductile interlayer cohesions competent incompetent high rheology, depth slickensides played crucial roles formation final evolution fold fault step-like system, composed lower crustal crystalline basement detachment surface, regional boundary fractures, overlying Cambrian Triassic synclines, necessary condition for zone controls overall Under action multiple phases activity main stress orientations, phenomenon superimposed directions observed at present formed. well-developed karst features are not conducive construction project tunnel where tightly closed back-slope, fissures, normal faults have developed