北石窟寺平顶窟顶板层状剥落破坏力学机制研究  

STUDY ON THE MECHANICAL MECHANISM OF LAYERED SPALLING DAMAGE OF THE FLAT ROOF IN BEISHIKU TEMPLE GROTTOES

作　　者：裴强强[1,2,3,4] 白玉书 郭青林 刘鸿[1,3] 陈卫昌 PEI Qiangqiang;BAI Yushu;GUO Qinglin;LIU Hong;CHEN Weichang(Dunhuang Academy,Dunhuang 736200,China;Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province,Lanzhou University of Technology,Lanzhou 730050,China;Research Center for Conservation of Cultural Relics of Dunhuang,Dunhuang 736200,China;Cultural Heritage Conservation Design and Consultation Co.,Ltd.of Gansu Mogao Grottoes,Dunhuang 736200,China;Chinese Academy of Cultural Heritage,Beijing 100029,China)

机构地区：[1]敦煌研究院,敦煌736200 [2]兰州理工大学教育部土木工程防灾减灾工程中心,兰州730050 [3]甘肃省敦煌文物保护研究中心,敦煌736200 [4]甘肃莫高窟文化遗产保护设计咨询有限公司,敦煌736200 [5]中国文化遗产研究院,北京100029

出　　处：《工程地质学报》2024年第6期2041-2054,共14页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:U22A20599)。

摘　　要：以庆阳北石窟寺为代表的陇东石窟多开凿于弱胶结砂岩地层,呈现结构松散、胶结物含量与强度低、沉积原生层理面黏结力弱等特点,平顶窟容易发育顶板层状剥落病害。选取北石窟寺10处具有典型剥落病害特征的洞窟进行调查,获取岩层剥落病害的几何参数及分布特征。调查发现北石窟寺平顶窟顶板层状剥落的破坏特征呈现多阶段性,从底部最大拉应力区域开始发育裂缝,逐渐向上扩展剥落,形成步进式坍塌,直至构成稳定的极限平衡拱。考虑上覆荷载、层理面黏接力、端部支撑和水平构造应力等多种因素的综合作用,逐步推导了从固支梁模型到简支梁模型、悬臂梁模型,最终形成极限平衡拱模型的渐近演化过程,并结合结构力学和弹性力学理论建立了不同损伤阶段的典型力学模型,揭示了顶板层状剥落不同阶段病害特征和破坏机制,并提出了不同阶段破坏的临界范围及阈值。研究成果能够更精确预测砂岩平顶窟失稳趋势,可为顶板岩体稳定性评价和预防性保护提供理论支撑,对同类石窟的长期保护具有重要参考价值。The Longdong rock caves,exemplified by the Beishiku Temple in Qingyang,were primarily excavated in weakly cemented sandstone strata.These rock masses are characterized by loose structures,low cementation strength,and weak bonding along bedding planes,which predispose flat-topped cave roofs to stratified spalling.This study selected ten representative spalling caves in the Beishiku Temple,where field investigations were conducted to acquire geometric parameters and spatial distribution characteristics of the spalling damage.The findings indicate that stratified spalling in flat-topped roofs exhibits a distinct multi-stage progression.Cracks initially form in regions of maximum tensile stress at the base of the roof and gradually propagate upward,resulting in stepwise collapses and eventually the formation of an ultimate equilibrium arch.By comprehensively considering factors such as overburden load,bonding strength of bedding planes,end constraints,and horizontal tectonic stress,this study derived the asymptotic evolution process from a fixed-end beam to an ultimate equilibrium arch model.Mechanical models corresponding to each evolutionary stage were developed using principles of structural mechanics and elasticity theory.The research elucidates the staged failure mechanism and critical thresholds of stratified spalling in sandstone cave roofs.It enables accurate predictions of roof instability trends and provides a theoretical basis for evaluating roof stability and implementing preventive conservation measures.These findings offer valuable insights for the long-term preservation and sustainable protection of similar rock caves.

关 键 词：北石窟寺 顶板剥落破坏 破坏过程 力学模型 验证分析 

分 类 号：K879.2[历史地理—考古学及博物馆学]