基坑支护结构中超长混凝土板支撑的温度应力研究

Temperature Stress of Superlong Reinforced Concrete Slab Bracing in Foundation Pit Retaining Structure

介绍了混凝土支撑轴力计算理论,并将其应用于某大型基坑板支撑轴力监测布置和轴力换算,根据该基坑板支撑轴力、地连墙水平位移和温度监测数据,研究温度变化对超长钢筋混凝土板支撑轴力和围护结构变形的影响,通过两个工况模拟,验证、预测了板支撑轴力和地连墙水平位移随温度的变化规律,并得出如下结论:(1)板支撑轴力与温度的变化趋势相吻合,温度越高时,温度变化对板支撑轴力的影响越显著,日温差对支撑梁轴力的增幅最大可达30%,表明在支护与开挖工况稳定的情况下,温度作用是长板撑支撑梁轴力变化的主要原因;(2)板支撑处地连墙水平位移变化与温度变化具有较好的相关性,但随着深度的增加,温度变化对地连墙水平位移的影响减弱。

The calculation theory of axial force of concrete support is introduced,and applied to the axial force monitoring arrangement and axial force conversion of a large foundation pit slab support.According to the monitoring data of axial force of foundation pit slab support,horizontal displacement of ground diaphragm wall and temperature,the influence of temperature change on axial force of ultra-long reinforced concrete slab support and deformation of envelope structure was studied.The variation law of plate support axial force and horizontal displacement of ground connecting wall with temperature was verified and predicted,and the following conclusions are drawn:(1)The axial force of slab support is consistent with the trend of temperature change.The higher the temperature is,the more significant the influence of temperature change on the axial force of slab support is.The increase of daily temperature difference on the axial force of beam support is up to 30%,indicating that temperature is the main reason for the axial force change of long slab support beam under stable supporting and excavation conditions.(2)The horizontal displacement of the diaphragm wall at the plate support has a good correlation with the temperature change,but with the increase of depth,the influence of temperature change on the horizontal displacement of the diaphragm wall is weakened.