竖向地震荷载下人字批顶结构石窟的稳定性分析  

Study on seismic stability of grottos with gable roof under vertical seismic loads

作　　者：石玉成[1] 王旭东[2] 秋仁东[1] 郭青林[2] 

机构地区：[1]中国地震局兰州地震研究所,甘肃兰州730000 [2]敦煌研究院,甘肃敦煌736200

出　　处：《世界地震工程》2009年第4期148-152,共5页World Earthquake Engineering

基　　金：国家社会公益研究专项项目(2002DIB20062)

摘　　要：我国部分石窟的空间建造采用了人字批顶形式,体现了中国传统建筑形式与佛教石窟建造形式上的融合。选取莫高窟典型的人字批顶结构的254号石窟作为研究对象,建立了三维的石窟计算模型,考虑了竖向地震荷载作用,通过输入不同地震加速度时程,计算了4种模型情况下石窟岩体的拉应力分布情况。结果表明,石窟的人字批顶处易形成较大拉应力区,易遭受地震破坏;石窟中心塔柱可以有效地提高所在石窟岩体的抗震能力,但对下部窟体的上部岩体会产生应力集中,是窟体防护加固的重点部位。同时,对于洞窟密集而又分上下几层的石窟群,在抗震防护中应充分考虑竖向地震荷载的作用。Some of the Chinese grottos adopted a gable roof, which is a fusion of Chinese architecture tradition and that of Buddhism. In this paper, using No. 254 grotto with gable roof as an example, 3D numerical model of the grotto is established and its analysis is done incorporating consideration of vertical ground motion effect and different parameters of time history of ground motion. Working cases of four 3D models are calculated to get tensile stress dis- tribution in rockmass. The results show that the top of the gable roof endures strongest tensile stress and is relatively vulnerable under effect of strong earthquake. Although central pillar can improve seismic resistance of rock mass of grottos, it also causes stress concentration in rocks around both ends, where is the key spot for seismic reinforcement. For close grottos arranged in tiers the effect of vertical seismic loads is an important factor, which should be included for seismic safety of grottos.

关 键 词：人字形批顶结构石窟 围岩 竖向地震荷载 有限元模拟 

分 类 号：TU435[建筑科学—岩土工程] P315.98[建筑科学—土工工程]