大型圆形沉井结构应力及其周边沉降计算  

Stress of large cylindrical caisson structure and its adjacent settlement

作　　者：邓友生[1] 万昌中[1] 闫卫玲[1] 时一波[2] 肖本林[1] 赵明华[3] 

机构地区：[1]湖北工业大学土木工程与建筑学院,湖北武汉430068 [2]中铁大桥局集团第六工程有限公司,湖北武汉430100 [3]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《岩土力学》2015年第2期502-508,共7页Rock and Soil Mechanics

摘　　要：根据武汉鹦鹉洲长江大桥北锚碇大型圆形沉井结构特点与工程地质条件,结合施工现场沉降监测控制点的实测数据,采用大型有限元计算程序ADINA建立了三维计算模型,对沉井结构及其周围的地下连续防护墙进行了有限元分析,分析了沉井在下沉与封底过程中其结构自身的应力分布与变形情况,并探索了沉井在下沉过程中对周边邻近高层建筑与堤岸构筑物的影响。计算研究结果表明:沉井外围的地下连续防护墙主应力会随沉井的下沉而相应地增加,在沉井封底后其变形主要出现在上部和底部;而沉井在下沉过程中其结构底部的刃脚、十字隔墙、十字隔墙与环形井壁结合处均会出现较大拉应力;沉井的周边土体沉降量会随下沉深度而相应地增大。在沉井封底完成后测点的沉降理论计算值与实际监测值比较吻合,一般计算值较监测值稍小:二者的差值在邻近高层建筑的沉降控制测点为-1.22^-0.88 mm;而在附近的长江大堤处的关键测点为-1.27~0.64 mm。该计算模型对锚碇沉井下沉过程的沉降控制具有参考作用。Given the structural features and engineering geological conditions of north anchorage large cylindrical caisson of Wuhan Parrot Cay Yangtze River bridges, combining with in-situ monitored data of some key points, three dimensional calculation modes of FEM are established with software ADINA to analyze stress and deformation of caisson structures and its adjacent diaphragm wall. The stress distribution and deformation of the structures are studied during the caisson sinking and its bottom sealing. The effects of caisson sinking on adjacent high-rise buildings and bank structures are also analyzed comparatively. The research results show that： the principal stress of diaphragm wall increases with the increasing of sinking depth, and its deformation appears mainly in its top and bottom after the caisson bottom sealing, the tension stress would be higher at its structure cutting edge, the middle of cross wall, the joints of cross wall and inner face of caisson well. The corresponding settlement of adjacent soil around the caisson increases with the increasing of sinking length as well. Settlements of monitored points from calculation agree well with measured data after bottom sealing, and the former is generally less than the latter. The differences between them are from -1.22 mm to -0.88 mm at the key points of adjacent high-rise buildings, and those at the key points near the Yangtze River bank are from -1.27 mm to 0.64 mm. The calculation model will provide a guide for settlement control during the caisson sinking.

关 键 词：锚碇沉井 地下连续墙 有限元 应力 沉降 监测 

分 类 号：TU753.64[建筑科学—建筑技术科学]