ESTIMATION OF SALT-SOLUTIONED CAVERN GEOMETRY FROM SUBSIDENCE TROUGH CONFIGURATIONS UNDER SUPER-CRITICAL CONDITION

บทคัดย่อ

Physical model tests are performed using a trap door apparatus to simulate surface subsidence as affected by size and shape of salt-solution caverns created at the interface between salt and overlying soil formations.  Fine sand (2 mm) is used as overburden material.  The maximum subsidence and trough width are measured using 3-D laser scanner.  Numerical simulations using PFC code are performed to compare with the model results and to correlate the cavern geometries under a variety of cohesions and friction angles of the overburden.  The results indicate that the surface subsidence and trough width increase with increasing cavern width and height.  Under the same cavern height, the maximum subsidence slightly decreases with increasing the overburden thickness.  The computer model results agree well with those obtained from the physical model results.  Set of empirical equations is derived to fit with the physical model results, which can be used to estimate the cavern height and width from the subsidence trough configurations and overburden mechanical properties.