Study on the Characteristics of Damaged Sandstone in the Longshan Grottoes Using Water Chemistry and Freeze–Thaw Cycling

Sandstone from the Longshan Grottoes in Taiyuan, China, was research object of this paper. The sandstone samples were soaked distilled water, Na2SO4 solution, and NaCl solution subjected to freeze–thaw testing. specimens treated with 0, 5, 10, 15, 20, 25, 30 cycles. mass ratio, P-wave velocity, surface hardness, uniaxial compressive strength, other physical-mechanical features rock measured after different numbers results mercury injection, scanning electron microscopy, X-ray diffraction combined explore damage mechanisms characteristics under action chemicals It found that degree increased logarithmically number cycles, causing most damage. Damage variables D cycles 3.89%, 6.51%, 4.74%, respectively. difference between solutions is caused by combination frost heave, dissolution, salt crystallization, process generally occurs inside outside manifested as an increase macropores appearance new pores. Freezing–thawing are important causes powdering detachment Grottoes.