Study On The Mechanism Of The Improvement By Jetting And Bearing Of The Positive Pressure Platform Foundation

It is important to improve the soft subsoil in seabed in order to use as the foundation of the platform. The concept of the positive pressure platform treated by jetting is an innovation of the construction technology of platforms. The mechanism of the improvement by jetting and bearing of the positive pressure platform foundation is one of the crucial techniques that have to be solved as soon as possible. This paper carries out a research on the mechanism for the soft clay subsoil in the shallow sea and following conclusions are reached:By comparing all the feasible plans based on the soil properties in the Shengli oil field, the treatment scheme of the platform foundation is proposed. That is to penetrate the short rigid piles to the required depth by jetting and form composite foundation with cement soil. Furthermore the failure mode of the composite foundation is represented and the improvement mechanism focusing on this failure mode is studied.The material for the foundation treatment and the additives are selected rationally. Then the solidification mechanism of cement soil is discussed and the mechanical features and the corrosion on the cement soil by the sea water are analyzed. Also the compounding tests of cement soil are carried out.The mechanisms of the vertical and lateral bearing of the composite foundation are analyzed and the formula to calculate the bearing capacity of the treated foundation is selected, which provide a basis for the software development of the capacity calculation.The software to compute the bearing capacity of the composite foundation treated by jetting of the positive pressure platform is developed. Then the basic function and principle of the software are described, program flow diagram and interface demonstration are provided. In addition, the accuracy of the software is verified with actual example. The bearing capacity of the composite foundation treated by jetting of the positive pressure platform is calculated. The sensitivity analysis is implemented to discover the influence of the soil properties on the bearing capacity.