考虑接触非线性的西安明城墙稳定分析  

Stability analysis of Xi’an city wall considering nonlinear contact

作　　者：张柯[1] 吴敏哲[1] 孟昭博[1] 李志宏[2] 

机构地区：[1]西安建筑科技大学土木工程学院,西安710055 [2]机械工业勘察设计研究院,西安710055

出　　处：《岩土力学》2010年第9期2913-2918,2929,共7页Rock and Soil Mechanics

摘　　要：西安明城墙是由内芯土和外包墙组成的人工黄土边坡。强度折减有限元法是分析土坡稳定性、确定土坡最小安全系数的有效方法,但应用该方法计算城墙的安全系数时,却难以处理外包墙上的潜在破坏面对城墙稳定性的影响。根据外包墙破坏的实际情况,假设了不同形式和位置的潜在破坏面来模拟外包墙的破坏形态,通过考虑软化性能的界面本构方程,应用强度折减有限元法确定了外包墙的最危险破坏形态,并基于此破坏形态研究了影响城墙稳定性的主要因素,可为古城墙的稳定性评估和保护修缮提供依据。分析表明,城墙内芯土潜在滑动弧可简化为一条直线,其顶点位于坡肩内约3m处;城墙沿该滑动弧的安全系数满足稳定性要求;外包墙的破坏形态和砂浆强度、外包墙与内芯土之间的摩擦系数是影响城墙变形破坏的主要因素。Xi＇an city wall is an artificial loess slope composed of inner-soil and outer-brick masonry. Strength reduction FEM is an effective method for analyzing the slope stability and calculating the safety factor. But when it is applied to analyze the wall＇s stability, such difficulties emerge as the potential fracture face in the outer-brick masonry and the interface between inner-soil and outer-brick masonry. According to the contact condition, a plastic interface constitutive equation considering the softening on shear capacity is developed to analyze the stability of Xi＇an city wall by using strength reduction FEM. The results indicate that the potential slip circle could be simplified to a line with the vertex 3 m away from the slope shoulder. And the safety factor along this line can meet the engineering requirements of stability. Furthermore, several principal factors that affect the deformation and damage of the wall are determined, such as the shearing strength of outer-brick masonry and the friction coefficient between inner-soil and outer-brick masonry. So it can serve the stability assessment and renovation of the city wall.

关 键 词：城墙 稳定性 界面本构方程 强度折减有限元 

分 类 号：TU435[建筑科学—岩土工程]