In order to investigate the shear characteristics of salt rock in brine soak environment during the process of salt cavern building

an orthogonal experiment is designed to investigate the influences of brine soak time

temperature and loading rate on the shear properties of salt rock. The experimental results show that: brine soak weakens the shear strength of salt rock

and the longer the brine soak time is

the lower the shear strength of salt rock is

but the shear strength will be stabilized eventually; the increasing of brine temperature exacerbates internal damage of salt rock

which decreases shear strength; the shear strength of salt rock

soaked in a certain temperature brine

decreases with the increasing of loading rate. And the ductile characteristics of salt rock are gradually weakened with the increasing of soak time

temperature and loading rate. The binary linear regression is respectively conducted by any two factors

the relative importance ratio is used to build judgment matrix according to the standardized regression coefficients for salt rock’ shear strength

and weights of various factors are calculated by analytic hierarchy process. The weights of temperature

loading rate and soak time respectively are 0.397

0.340

and 0.263. The results of range analysis and weights calculation show that the primary factor affecting the shear strength of rock salt is temperature

and the secondary factor is loading rate

followed by the soaking time.