Abstract:

The swelling properties of limestone and sandstone at 300 ℃ to 700 ℃ were investigated by the experiment system used to measure the swelling properties of rocks at high temperature and designed by ourselves. The experimental results show that the swelling stresses of limestone and sandstone increase with temperature increasing during raising temperature; and the swelling velocity of sandstone is more quickly than the limestone. The swelling stress of sandstone is 2.45 times as that of limestone when just reaching to 700 ℃. The fitted functions of curves about swelling stress and temperature are second-degree parabolaes during raising temperature; and the related coefficients are all above 0.94. The swelling stresses of two kinds of rocks increase slowly during constant temperature with time prolonging and tended to steady values at last. Two kinds of rocks’ swelling stresses reach to the limit values at 600 ℃; but the specific processes are different. The swelling stress of sandstone is 3.14 times as that of limestone when constant temperature process finished at 700 ℃. The swelling stress of rock is obviously related to lithological characters, mineral resolving, porosity and sound velocity.

Key words: limestone, sandstone, high temperature, unidirectional restraint, swelling stress