盾构隧道侧穿引发砌体建筑物变形损伤实例研究

Case Study on Deformation Damage of Masonry Building Caused by Lateral Crossing of Shield Tunnel

现有关于盾构隧道侧穿砌体建筑物的研究,大多只针对砌体建筑物沉降和整体倾斜指标进行分析,当砌体建筑物发生不均匀沉降时,容易产生裂缝,仅从这两项指标不能分析建筑物开裂损伤情况。在使用常规本构模型进行盾构隧道侧穿数值模拟计算时,既不能体现砌体建筑物独特的结构,也不能反映出建筑物上发生的开裂和应变情况。基于此,以呼和浩特地铁1号线盾构隧道侧穿玛拉沁饭店为工程背景,在数值模拟中使用节理砌体本构模型进行有限元计算,并结合工程实测数据对盾构侧穿后建筑物不均匀沉降和应变情况进行分析。结果表明:(1)盾构隧道侧穿砌体建筑物后,砌体建筑物的开裂区域是从下往上发展的,拉伸应变较大的区域主要集中在建筑物最底部,大部分拉伸应变区域与门洞位置相关联;(2)砌体建筑物不均匀沉降区域集中在建筑物的门窗洞口位置,不均匀沉降较大的区域与应变较大的区域相对应,该区域更容易发生开裂;(3)随着砌筑砂浆黏聚力的增加,砌体建筑物发生的应变和不均匀沉降逐渐减小,砌体建筑物易开裂区域逐渐减少。

Most of the research into lateral crossing of masonry building by shield tunnel conducted so far is focused on analysis of settlement and overall inclination of the masonry building.A masonry building that experiences differential settlement is susceptible to cracking,so the aforesaid two indicators are not enough to analyze the crack damage of the building.The numerical simulation calculation of lateral crossing of shield tunnel that uses conventional constitutive model does not take into account the unique structure of masonry building or the crack and stress of the masonry building.In this study,therefore,the lateral crossing of Malaqin Restaurant by the shield tunnel of Hohhot Metro Line 1 is used as the example.In the numerical simulation,finite element calculation is conducted by using the jointed masonry constitutive model.The differential settlement and strain of the building resulting from lateral crossing by the shield are analyzed by using the measurement data.As the results indicate:(1)After lateral crossing of the masonry building by a shield tunnel,the cracking area of the masonry building develops from the bottom up,the tensile strain is mostly concentrated at the lowermost part of the building,and most tensile strain regions are related to the position of the door opening.(2)The differential settlement areas of the masonry building are concentrated at the door and window openings,and the areas with major differential settlement are the areas with major strain which are more susceptible to cracking.(3)As the cohesion of masonry mortar increases,the strain and differential settlement of the masonry building gradually decrease,and the areas on the masonry building that are susceptible to cracking gradually decrease.