摘要
南京“包山式”古城墙以其独特的外包墙体和内侧山体紧密咬合承载机理成为中国古城墙的代表作。但雨水渗透显著影响城墙稳定机理,这是导致城墙开裂和失稳坍塌的直接原因。为研究雨水渗透对南京“包山式”城墙稳定性的影响:基于古城墙砖砌体与土体间的“咬合”作用,采用库仑土压力理论的改进计算方法;以南京城墙神策门段城墙为研究背景,利用Geo-studio软件中的SLOPE/W模块,分析土体含水率变化对城墙稳定性安全系数的影响;采用ABAQUS软件构建数值分析模型,模拟并对比了四种不同土坡水位工况下城墙外包砌体的位移、应力和应变变化。研究结果表明:考虑城墙与土体间的“咬合”作用和土体的黏聚力后所得到的土压力合力值大于朗肯土压力理论值;古城墙内侧土体的含水率维持在10%~17%之间时,城墙的整体稳定性能够保持在较高的水平;城墙外包砌体在水位上升时沿墙高方向展现出“抛物线”型的水平位移增加,特别是水位上升到城墙顶部2 m时,城墙底部1 m高度的主拉应力显著增加,表明该区域极易出现拉裂缝。研究结果可为南京“包山式”古城墙的安全评估与保护修缮提供科学依据。
The city wall of surrounding mountain in Nanjing,characterized by its unique outer masonry and close integration with the inner mountain terrain,represents a typical example of ancient Chinese city walls.Rain infiltration has a significant impact on the wall's stability,often leading to cracking and partial collapses.To investigate the influence of rainwater infiltration on the stability of the wall of surrounding mountain,this study established a model based on the interfacial interlocking mechanism between the ancient masonry and the adjacent soil mass,employing an improved calculation method derived from Coulomb's earth pressure theory.Using the Shence Gate section of the Nanjing's city wall as a case study,the Geo-studio software's SLOPE/W module was applied to analyze changes in the wall's stability factor under varying soil moisture conditions.Additionally,a numerical model was developed using ABAQUS software to simulate the displacement,stress,and strain responses of the external masonry under four different water table conditions.The results indicate that the resultant earth pressure,accounting for the interlocking action between the wall and the soil as well as soil's cohesion,is greater than that predicted by Rankine's earth pressure theory.The city wall maintains high stability when the soil moisture content within the wall structure remains between 10%and 17%.The horizontal displacement of the outer masonry increases parabolically with rising water levels.Particularly,when the water level reaches 2 meters below the top of the wall,the principal tensile stress at 1 meter above the wall's base rises sharply,indicating a high risk of tensile cracks in this region.This study provides a scientific basis for the safety evaluation and conservation of the city wall of surrounding mountain in Nanjing.
作者
魏慧敏
王南南
王志强
穆保岗
WEI Huimin;WANG Nannan;WANG Zhiqiang;MU Baogang(School of Civil Engineering,Southeast University,Nanjing 211189,China;Nanjing City Wall Protection and Management Center,Nanjing 210000,China;Office of the Jiaozuo Municipal People's Government,Jiaozuo 454150,China;Jiangsu Dongda Engineering Testing Technology Co.,Ltd.,Nanjing 211102,China)
出处
《文物保护与考古科学》
北大核心
2025年第6期112-122,共11页
Sciences of Conservation and Archaeology
基金
江苏省文物科研课题(No.2020SK14)
南京城墙科技项目(2023-NJCHQ-002)资助。
关键词
古城墙
雨水渗透
有限元分析
稳定性
土压力
Ancient city wall
Rainfall infiltration
Finite element analysis
Stability
Earth pressure
