Abstract:

Adopting the large physical simulation experiment with the Longmenshan fault zone as the research background, it reproduced the imbricated thrust fault evolution process. By the real-time monitoring of displacement and strain in inside of the model, it was concluded the deformation and stress distribution law of imbricate thrust fault as follows:1)The deformation of the whole tectonic region is inclined up along the fault zone except partly inclined down of underlying fault footwall; the deep deformation is greater than shallow surface at the same side of fault zone; the horizontal deformation gradually decreases with the increase of the distance from the extrusion end, and accompanied by instaneous jumping increase.2)The research area is in compressive stress state except local tensile stress in the shallow of the upper wall,and the deep stress and its release quantity are much greater than the shallow; the stress does not increase or decrease linearly, but with the increasing displacement of extrusion end along a trend shocks up and down. The crustal stress near the underlying fault zone is more likely to appear accumulation and release. In the changing time, the deep is jumping decrease, but the both side of the underlying fault zone instantly increase at first then decrease gradually.3)The deformation and stress of shallow changes with the same rule, but all are lagging behind the deep.

Key words: imbricated thrust fault, Longmenshan, crustal stress, simulation experiment