摘要
南京城墙根据受力特点可分为自承重式城墙和包山式城墙,其中包山式城墙易受后侧土坡影响发生整体式失稳破坏。为了获得包山式城墙发生失稳破坏的顶点变形预警值,将土体作用下的包山式城墙简化为城墙、粘结界面和土坡三部分,对城墙采用混凝土塑性损伤模型进行整体建模;假设土坡符合Mohr-Coulomb定理,同时定义粘结界面法向和切向系数。数值模拟分析时,采用强度折减法模拟降雨情况下土体强度指标下降情况;当城墙顶点的位移发生突变时,令其为发生整体失稳破坏的预警值。最后,以南京城墙小桃园倒塌段为例进行分析,数值模拟结果与实际情况相符,同时还与单自由度假设下的砌体墙平面外计算理论进行对比,两者变形规律相似。
Nanjing city wall can be divided into self-bearing type wall and baoshan type wall according to the stress characteristics,among which the baoshan type wall is prone to integral instability under the influence of the soil slope at the back.In order to obtain the peak deformation warning value of Baoshan type city wall under the action of soil,the city wall under the action of soil is simplified into three parts:the city wall,the bond interface and the soil slope,and the concrete plastic damage model is adopted to model the whole city wall.It is assumed that the soil slope conforms to the Mohr-Coulomb theorem,and the normal and tangential coefficients of the bond interface are defined.In numerical simulation analysis,strength reduction method is used to simulate the decline of soil strength index under rainfall condition.When the displacement of the top of the wall is abrupt,it is made to be the early warning value of overall instability failure.Finally,taking the collapsed section of Xiaotaoyuan of Nanjing City Wall as an example,the numerical simulation results are consistent with the actual situation.At the same time,the numerical simulation results are compared with the out-of-plane calculation theory of masonry wall under the assumption of single degree of freedom,and the deformation rules of the two are similar.
作者
程浩然
敬登虎
CHENG Hao-ran;JING Deng-hu(School of Civil Engineering,Southeast University,Nanjing Jiangsu 211189China)
出处
《江苏建筑》
2021年第S01期1-4,共4页
Jiangsu Construction
关键词
包山式城墙
失稳破坏
塑性损伤
强度折减法
预警
数值模拟
baoshan type city wall
instability failure
plastic damage
strength reduction method
early warning
numerical simulation
