The influence of environmental humidity change on the stability of rock caves in Longyou Grottoes

Abstract

Silty sandstone grottoes are suffered climate changes. The Longyou Grottoes are typical argillaceous siltstone. This paper utilized the coupled humid-mechanical-damage model to investigate the influence of environmental humidity change on the deformation and stability of Cave 4 and Cave 5 in Longyou Grottoes. It is found that the change in environmental humidity significantly influences the stability of caves in Longyou Grottoes. The water saturation of surrounding rock changes with the increase or decrease of ambient humidity. The water swelling and dry shrinkage processes greatly affect the stress state and mechanical properties of the surrounding rock, resulting in micro-cracks which may form fractures that disturb the structural integrity and aggravate the geological hazard of weathering. The cave roof is the most dangerous position during the humidity variation. Pre-existing fissures act as shortcuts for humidity diffusion and stress generation. In turn, the fast diffusion rate and high stress cause further propagation of the fissures. Repairing pre-existing fissures and applying waterproof measurements on the inner wall of caves contributes to the stability and durability of the grottoes. This study improves the understanding of the relationship between the changes in environmental humidity and the weathering of grottoes and provides theoretical support for the subsequent disaster risk management and preservation of Longyou Grottoes.