Abstract:

Numerical simulation with finite element method is adopted to analyze deformation and mechanical properties of layered salt rock. Firstly, with numerical experiment method, macro-equivalent elastic-mechanics parameters of layered salt rock with mudstone interlayers are predicted; and then a micro-finite element model of layered salt rock is established; micro-stress and strain distribution and stress concentration are studied under uniaxial and triaxial loadings. The above numerical simulation is compared with the corresponding experimental and theoretical study. The results show that the micro-finite element method, an effective method, can forecast the macro-mechanics properties of layered salt rock; the mechanical properties mismatch of two adjacent layers results in obvious stress concentration and differential deformation at the interlayer and interface; an equivalent tension stress is applied on the stiffer interlayer and correspondingly an equivalent compression stress is applied on the weaker salt rock under uniaxial loadings. While under triaxial compression, micro-stress and strain distribution of layered salt rock is complicated under different confining pressures and deviator stresses. The present study can intuitively analyze deformation and failure characteristics; it also provides a theoretical basis for further study of the stability of the oil/gas storage cavern in layered salt rock formation.

Key words: layered salt rock, interlayer, micro-stress and strain, stress concentration