Monitor and Control for Caisson Foundation Construction of Wufengshan Changjiang River Bridge

摘要

ublishercopyright>? 2019, Journal Press, China Railway Bridge Science Research Institute, Ltd. All right reserved.? 2019, Journal Press, China Railway Bridge Science Research Institute, Ltd. All right reserved. The main bridge of the Wufengshan Changjiang River Bridge is a suspension rail-cum-road bridge with a main span of 1 092 m and a structure of steel truss girder, and the caisson foundation with sizes of 100.7 m×72.1 m×56 m is adopted for the north anchorage. The caisson consists of a concrete-filled steel box for the first section and reinforced concrete structures for the rest nine sections. The plan of "height extending for 3 times and sinking for 3 times" is used in the caisson construction. In order to timely know the geometric attitude and stress conditions of the caisson in construction stages, a real-time online monitoring system is established to automatically survey the geometric attitude, stresses of caisson structure, and soil pressure of blade foot of caisson. Meanwhile, the caisson sinking is timely controlled according to the monitoring data. The results show that the elevation difference and inclination of the caisson are all within the limited values, the deflections of caisson are all within the limited value 20 mm, and the geometric attitude of caisson can meet the requirements of controlled parameters. The measured stresses of concrete and steel structures are basically within the limited values and the measured soil pressures are all controlled within the limited value 1.20 MPa. It is revealed that the caisson structure is in good force condition and can meet the requirements of controlled parameters.The main bridge of the Wufengshan Changjiang River Bridge is a suspension rail-cum-road bridge with a main span of 1 092 m and a structure of steel truss girder, and the caisson foundation with sizes of 100.7 m×72.1 m×56 m is adopted for the north anchorage. The caisson consists of a concrete-filled steel box for the first section and reinforced concrete structures for the rest nine sections. The plan of "height extending for 3 times and sinking for 3 times" is used in the caisson construction. In order to timely know the geometric attitude and stress conditions of the caisson in construction stages, a real-time online monitoring system is established to automatically survey the geometric attitude, stresses of caisson structure, and soil pressure of blade foot of caisson. Meanwhile, the caisson sinking is timely controlled according to the monitoring data. The results show that the elevation difference and inclination of the caisson are all within the limited values, the deflections of caisson are all within the limited value 20 mm, and the geometric attitude of caisson can meet the requirements of controlled parameters. The measured stresses of concrete and steel structures are basically within the limited values and the measured soil pressures are all controlled within the limited value 1.20 MPa. It is revealed that the caisson structure is in good force condition and can meet the requirements of controlled parameters.