基于谱表示法和时间衰变模型的岩体稳定性评价

Stability analysis on dangerous rockmass based on spectral representation method and time degradation model

为了从时间尺度和空间变异性上研究石质文物危岩体的结构稳定性,建立了岩体强度参数的空间分布和时间退化模型。选取麦积山石窟13号窟危岩体为研究对象,利用强度折减法对石窟岩体稳定性进行模拟计算。模拟结果表明:①麦积山13号窟现状条件下最大位移为1.8 mm,中部位移方向略微倾向石窟外侧,石窟顶部呈现局部塑性变形,但整体稳定性较好,模拟结果与现状调查较为一致。②加入时间衰变模型后发现,13号窟现状条件下顶部位移为1.2 mm;预测50 a后洞窟最大位移位于洞顶,为1.3 mm;100 a后洞窟最大位移从洞顶转移至坡脚,为16.7 mm。③强度折减分析表明,100 a后模型产生大面积塑性区域贯通现象,洞顶发生拉张破坏,洞底剪切破坏。时空变异模型有效提高了传统静力学计算精度,通过时间退化模型真实地再现了石窟危岩体的动态破坏过程,在精确评价危岩体长期稳定性方面具有广泛应用价值,可为危岩治理提供参考。

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.