EFFECTS OF SHALLOW SALT CAVITY ON SUBSIDENCE PROFILES UNDER SUPER-CRITICAL CONDITION
Keywords:
Subsidence, physical mode, settlement, salt cavity, friction angleAbstract
Physical model tests were performed to study surface subsidence under various widths and heights of shallow salt cavity induced at the boundary of salt bed and overlying soil stratum. Uniform spherical acrylonitrile butadiene styrene plastic (ABS) balls with 6 mm diameter were used to form particulate medium of the overburden. Width and depth of settlement trough under different geometries and depths of salt cavity were measured by 3-D laser scanner. PFC code was used to correlate the subsidence components with cavity geometries. Results show that depth of surface settlement is mainly controlled by cavity height, while the extent of settlement area is governed by cavity width. Results from discrete element analyses agree reasonably with those of physical model. Sets of empirical equations were developed to correlate the test measurements with the numerical results. They are applicable for predicting cavity height and width based on the configurations of settlement trough and friction angles of overburden.
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