Abstract:

 Based on the monitoring data of pulling and arching supporting structure of deep foundation pit in Jinan, the correlations of  cable stress, displacement and internal force of the pile were studied. The factors that influence the displacement of excavations and the settlement of surrounding buildings were discussed.Some useful conclusions were drawn, which could help the pit design and construction. First,the monitoring data of foundation pit anchor cable tension analysis showed that the loss of prestress was bigger with the improper measures when the cable was stretched. Second, by setting the inclinometer pipe and steel bar stress gauge monitoring of pile displacement and internal force analysis, the point of inflection of displacement and internal force of pile appeared when the pit was bottomed, and the displacement and internal force of pile could be effectively controlled by combined action of top beam and anchor cable. Third, based on the observation and analysis of settlement of surrounding buildings, it was found that the distance to pit edge and dewatering were the key factors of surrounding building settlement. The settlement of building surroundings pit could be ignored with better soil conditions.

Key words: displacement, internal force, pulling force;monitoring, settlement, pile-anchor structure