The boreholes in frozen coal mines of western China mainly cut through the Cretaceous and Jurassic rock formations characterized as water-rich and weakly cemented strata. The rock mass in the frozen wall undergoes a complete freeze-thaw process under the coupling effect of temperature field and crustal stress field. In this paper

considering the coupling effect of the temperature field and the geostress field in the process of freezing and thawing

the Cretaceous water-rich and weakly-bonded red sandstone is selected to see its mechanical properties based on experiments. Meanwhile

the deterioration mechanism of Cretaceous weakly cemented red sandstone induced by freeze-thaw process as well as the influence of crustal stress during the freeze-thaw process are analyzed. During freeze-thaw process

the confining pressures are set to be 0

2

4

6

8 MPa separately

the freezing temperatures are ?5

?10

?15 ℃ separately

and the thawing temperature is 20 ℃ for all samples. The results show that the Cretaceous weakly cemented red sandstone is very sensitive to freezing and thawing process because of its very poor cementation and low strength. After only one freeze-thaw cycle

the uniaxial compression strength decreases 28.39%. The crustal stress during the freeze-thaw process enhances the binding forces of pores and cracks of Cretaceous weakly cemented red sandstone

therefore the freezing fully develops to the secondary micro-cracks. Due to the further development of freezing effect

the frozen-heave force in the red sandstone increases

strengthening the damage of red sandstone. Therefore

the mechanical properties of red sandstone after melting are further reduced relative to the non-confined freezing and thawing condition. The experimental results in this paper is helpful for the design of shaft lining of borehole located in the frozen coal mines in western China.