力学顺序分层的泥岩涂抹过程-自由上表面水饱和模型实验结果
The aim of this study is to improve our knowledge of the processes that lead to clay smear during faulting ofa layered sand-clay sequence in an analogue sandbox model. We carefully characterized mechanical properties of thematerials used by a series of geotechnical tests. Displacement field was quantified using PIV (Particle Image Velocimetry).The model is water-saturated to allow the deformation of wet clay and sand in one experiment comprising a sandpackage with a horizontal layer of clay above a predefined rigid basement fault. The thickness and rigidity of the claylayer are the parameters varied in this study. The model shows a range of structures that are related to competencecontrast between sand and different clay types. Results show ductile shearing of soft clay with a transition to brittlefracturing of stiff clay accompanied by the formation of rotating clay blocks in the fault zone. Localized deformation isobserved through time showing (i) the propagation of one active fault migrating laterally through the sediment package,and (ii) the formation of a stable prism between two or more active faults that gets progressively smaller with minorrotation of the hanging wall fault. Continuous clay smear is observed resulting from the lateral injection of clay as wellas from a reworked mixture of sand and clay.