关键词: 麦积山石窟;时空变异性;非平稳随机过程谱表示法;危岩体稳定性;石质文物;

Abstract: In order to study the structural stability of stone cultural relic dangerous rock masses from time scale and spatial variability, a model of spatial distribution and time degradation of rock mass strength parameters was established.The dangerous rock mass of Grotto 13 in the Maiji Mountain Grottoes was selected as the research object.The strength reduction method was used to simulate and calculate the rock mass stability.The simulation results show that the maximum displacement under the current conditions of the Maiji Mountain Grotto 13 is 1.8 mm, displacement direction of the middle part is slightly inclined to the outside of the cave, and the top of the cave shows local plastic deformation, however the overall stability is good, and the simulation results are consistent with the current survey.By using the time degradation model, it is found that the top displacement of Grotto 13 is 1.2 mm under current conditions, and the maximum displacement of the cave is predicted to be 1.3 mm after 50 years, still locating at the cave top, however the maximum displacement of the cave will be transferred from the cave top to the slope foot after 100 years, reaching 16.7mm.It shows that the model will have a large plastic area penetration phenomenon after 100 years, top of the cave shows tensile failure, and the bottom of the cave shows shear failure.The spatio-temporal variation model effectively improves the accuracy of traditional static mechanicalcal culations, and the time degradation model truly reproduces the dynamic failure process of dangerous rock masses in caves.It has extensive application values in accurately evaluating the long-term structural stability of dangerous rock masses, and can be used as references for dangerous rock treatment project.

Key words: Maiji Mountain Grottoes; spatio-temporal variability; spectral representation method of nonstationary random process; stability of dangerous rock masses; stone cultural relics;