Influence of temperature stress on internal force and deformation of retaining structures for deep excavations

The influence of temperature stress upon internal force and deformation of retaining and structures for deep excavations is analyzed by monitoring the foundation pit of Wuhan Changjiang Shipping Center. The results show that the axial force of bracing system is increased by 41% and the horizontal displacement of the crown beams is decreased obviously when the temperature increases from 30℃ to 37℃. When the temperature drops, the horizontal displacement of the top crown beams increases 17 mm, and that of the lateral soils outside the retaining wall significantly lags behind the displacement of concrete retaining wall, resulting in large crack in soils between the wall and the side ditch. Some construction and technical measures are put forward to reduce the effect of temperature stress, and concrete strength should be increased by one grade if large temperature difference occurs during construction period. It is suggested that the allowable values of retaining structures should be appropriately reduced considering the displacement of supporting structures, the temperature influence coefficient should be 1.2 when the supporting length is greater than 40 m, and it should be above 1.4 without necessary thermal insulation and moisturizing measures. This research has important theoretical and practical significance for similar projects.