Simulation Experiment Study on Large-Size Sandstone Weathering Under Coupling Effect of Rainfall, Temperature and Sunlight

Grottoes are widely distributed in Gansu Province and most of them are carved into sandstone. Due to the vulnerability of the sandstone grotto temples and the fact that Gansu is prone to heavy rainfall in summer, the voids on the dry sandstone surface are filled with water and expand when the raindrops fall on the surface. After a rainfall, the sunlight gradually increases and water quickly dissipates. This intense drying-wetting cycle leads to weathering diseases of different degrees in the rock mass. On the basis of the multifactor variable coupling relationship of the environment of the sandstone grotto temples, a weathering simulation test of large-size sandstone was carried out in a multi-field coupling laboratory under the conditions of rainfall, temperature and sunlight. The test results preliminarily revealed the rainwater infiltration characteristics, water content and temperature response characteristics as well as surface deterioration characteristics of sandstone under the action of rainfall, temperature and sunlight. In addition, sensitive areas were identified and the weathering mechanism of sandstone under the action of rainfall, temperature and sunlight was revealed, accumulating basic data for the research on weathering mechanism of sandstone grotto temples and the research and development and application of anti-weathering technologies.