某在役明城墙病害调研及评估方法

Pathologies investigation and assessment method of an ancient City Wall in Ming Dynasty

评估在役古城墙的病害等级对其制定修复方案具有重要意义。以西部某明城墙为研究对象,对其存在的风化、裂缝、不均匀变形、受水分入渗、整体损伤程度等病害特征及诱因进行了大量调研分析和无损探测研究,基于古城墙砌体和夯土材料的损伤力学机理和专家建议,提出了描述上述病害程度等级指标的确定方法。建议将该明城墙病害分为A级(微弱)、B级(轻度)、C级(中度)和D级(重度)4个等级,并采用数值方法、模糊数学理论和层次分析法,建立了古城墙病害等级模糊评价系统及可视化评价平台。研究结果表明:(1)基于无损探测技术来获取明城墙病害数据库,结合古建筑材料的损伤理论,可系统量化在役明城墙的病害等级;(2)评估系统能够很好的应用于古城墙的病害诊断中,该明城墙南墙的病害程度最严重,西、北墙次之,东墙保存较完好,其病害客观评估结果与现场调研结果基本吻合,可在同历史时期建造的古建筑砖-土结构的病害评估中推广应用。

Assessing the damage grading plays an important role in establishing repairing schemes of the ancient City Wall(ACW).a City Wall in west regeion in Ming Dynasty is taken as research object,the damage features and causes of weathering,cracks,uneven deformation,water invasion and overall damage degree in the ACW are largely investigated and studied with non-destructive detection methods.Based on the damage mechanism of the masonry and rammed soil in the ACW and professional proposal,the defining methods of damage grading indexes of mentioned above in the ACW are proposed.The damage degrees are divided into four grades,such as grade A(weak damage),grade B(mild damage),grade C(moderate damage)and grade D(severe damage).The fuzzy comprehensive evaluation system and visual assessment platform of the damage grading of the ACW are established by using the numerical method,fuzzy mathematics and Analytic Hierarchy Process method.Based on the non-destructive detection methods and damage mechanism of materials in the ACW,the damage database of which can be established to quantify and analyze the damage grading;The assessment results with proposed platform show that the south wall of ACW is damaged more severely than that of the west and north wall,the east wall is perfectly preserved.The objective damage assessment of the ACW is well agreement with the subjective cognition during the investigation.The proposed evaluation system and platform are suitable and can be used in the similar ancient buildings constructed with masonry-rammed soil.