Application And Study Of Underwater Vacuum Preloading Method

Due to the poor geological conditions in Tianjin, the high-piled wharf is the main structural wharf type, and the slope stability is crucial. Especially when the width of bearing platform was limited, the slope stability has been the biggest challenge, so it was necessary to strengthen the soft groundwork. Vacuum preloading has been widely used in projects such as ports, roads and water conser vancy. However, underwater vacuum preloading has not been com prehensively adopted in engineering practice. The mechanism of underwater vacuum preloading is also unclear and there are m any problems to be solved in the technique of underwater operation.Combining the project practice, this thes is carried out a series of research work about underwater vacuum preloading techni que by means of theoretical analysis and numerical simulation.Firstly, the characters of high-piled wharf and its structure connecting shore were analyzed, the methods of slope stability and stability calculation were introduced.Secondly, the com parison and selection of bank slope stre ngthening schemes were made aiming at the project of Sinochem Petrochemical Jetty. Key technology of underwater vacuum preloading was described, and the scheme design was carried out.Then, the measured data was arranged and analyzed. The consolidation degree of soils after being treated by vacuum prel oading surpassed 90%, which achieved the projected objectives, and its construction technology was tested and further improved. So the rationality of the design and the st rengthening effect of underwater vacuum preloading were further validated.Lastly, the process of preloading was sim ulated by the ABAQUS s oftware. Comparing of the results of numerical simulation and field measurement data showed a good agreement of the settlement curve and the pore water pressure curve.To sum up, based on the engineering pr actice of bank slope strengthening under the condition of narrow platform, the design and theoretical analysis of underwater vacuum preloading technology are carried out. And the feasible m ethod of finite element simulation is p ut forward and validated. The work of this thesis has gr eat significance to the applicat ion and popularization of unde rwater vacuum preloading technique.