(1. College of Civil Engineering，Chongqing University，Chongqing 400045，China；2. Academy of Dazu Rock Carvings，Chongqing 402360，China；3. Chongqing Bureau of Geology and Minerals Exploration，Chongqing 401121，China)
Abstract：Grotto temples are located in environments that are subject to long-term alternating effects of cooling and heating，and temperature variations commonly lead to changes in the mechanical properties of the grotto surrounding rock. The sandstone of the Dazu Grottoes in Chongqing was taken as the research object in this paper. The mechanical properties of grotto sandstone were investigated by uniaxial compression test and Brazil split test，and the stress-strain curve，strength，peak stress and strain，elastic modulus，and failure mode of grotto sandstone under different temperature and heating-cooling conditions were analyzed. The results show that the uniaxial compressive strength of sandstone decreased after 10 heating-cooling cycles. Compared to natural cooling，water cooling significantly reduced the uniaxial compressive strength of sandstone. The tensile strength of the sandstone was strongly influenced by the cooling method，with the lowest tensile strength under the low-temperature water cooling cycle. The peak strain of sandstone decreased after 10 heating-cooling cycles. Compared to natural cooling，water cooling cycles decreased the elastic modulus of sandstone，and it also decreased as the number of cycles increased from 5 to 10. The failure mode of sandstone under uniaxial compression was mainly shear failure，which became complex after heating-cooling cycles. The main difference of the failure modes of sandstone under Brazilian splitting was the shape and number of cracks. After water cooling cycles，the main crack of sandstone changed from linear to arc or formed secondary cracks.
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2024, Vol. 43 
