EXPERIMENTAL STUDY ON THE INFLUENCE OF DRY-WET CYCLE ON CREEP CHARACTERISTICS OF ARGILLACEOUS SILTSTONE IN LONGY-OU GROTTOES
Longyou Grottoes,a 1000-year-old historical site,has been significantly deformed and destroyed by long-term erosion and weathering and human activities.Aiming at the surrounding rock of Longyou Grottoes-argilla-ceous siltstone,this study explores the influence of water-bearing state and the number of dry-wet cycles on the short-term mechanical properties and long-term mechanical properties of argillaceous siltstone by simulating the dry-wet cycle test under the alternate changing environment of rainy season and dry season,combined with SEM analy-sis,uniaxial compression and uniaxial compression creep test.The results show that the dry-wet cycle will aggravate the deterioration of the internal structure of the rock,increase and connect the internal holes,and make the struc-ture loose.With the increase of the number of cycles,the peak strain and strength of rock gradually decrease in both dry and saturated state,and the damage in saturated state is more serious,and the uniaxial compressive strength of dry rock decreases in a negative exponential function.According to the creep curve,it is found that with the increase of dry-wet cycles,the instantaneous strain and total creep increase gradually,and the influence of wa-ter on the instantaneous strain is particularly significant.The long-term strength decreases with the increase of dry-wet cycles,and the long-term strength of saturated samples is 46％～51％of that of dry samples.Through Burgers model analysis,it is found that the instantaneous elastic modulus EM of dry samples is about 1.91～2.32 times that of saturated samples.The higher the number of dry-wet cycles,the smaller the instantaneous elastic modulus EM.However,the correlation between the time parameter Td and the viscosity coefficientηMrequired for steady-state creep and the stress level is not obvious,so it is difficult to fully reflect the comprehensive influence of dry-wet cy-cles and water on rocks.This study provides an important reference for understanding the rock deterioration mecha-nism of Longyou Grottoes and evaluating the long-term stability of the Grottoes.
万方数据
维普
