Stability and structural stress variation of the shaft tower foundation during frost heaving and thawing settling
Freezing method construction around tall tower causes lifting or settlement of tower founda-tion,which seriously threaten the stability of tower foundation and its structural safety.In order to solve the problem,symmetrical drilling,local freezing protection,and hot water circulation of temperature-controlled hole are adopted to avoid freezing front and tower foundation.The elevation of tower founda-tion is measured continuously during the process of drilling,frost heaving and thawing settling.The measurement results show that during the period of drilling,frost heaving and thawing settlement,the tower foundation successively experiences a process of slow subsidence,slight uplift,fast subsidence,and settlement stability.The maximum inclination value of the tower foundation is far less than the al-lowable value,and the freezing protection measures adopted effectively guarantee the stability of the tower foundation.the numerical simulation of tower structure stress is carried out with the monitoring data of tower foundation settlement.The simulation results show that the peak value of tensile stress on the upper surface of the main beam of the shaft tower appears between the pilaster and the main beam where the peak value of tensile stress on the upper surface of the main beam of the shaft tower increases with the increase of the inclination value of the shaft tower.When the maximum tensile stress on the up-per surface of tower girder is within strength limit of C25 concrete during the period of drilling,frost heaving and thawing settlement,the safety of tower structure can be guaranteed.A similar material model of temperature-topsoil-well tower interaction is established and simulation experiments are carried out.The experimental results show that the longer the freezing time,the lower the freezing temperature and the greater the lifting amount and settlement amount of well tower foundation after thawing settle-ment,and more time required for the stability of well tower foundation after thawing settlement,the peak value of the lifting amount of well tower foundation is much smaller than that of the thawing settle-ment amount of well tower foundation.The simulation results are consistent with the measured results and numerical simulation results.
万方数据
维普
