Study On The Action Mechanism And Construction Technique Of The Cement Stir Piles Of Red Clay

Cement stirring technique has been widely used for of reinforcement of saturated soft clay ground because of its maximum use of soil in situ, flexible reinforcement and low impact on existing buildings and environment. Many researches have been carried out and achievements made on reinforcement mechanism, design calculation and construction technique applying to silt, silty soil, clay and sandy soil with foundation bearing capacity less than 120kPa. However, few study has been done on bearing capacity and deformation calculation of composite foundation reinforced by cement stirring technique applying to red clay which is widely distributed in China. Treatment design theory, construction technique and quality control of the foundation mixed by cement and red clay. Therefore, a study has been done on chemical composition of red clay, mutual reaction, solidification, strength and control factors of mixed cement and red clay, mixing proportion of mixed red clay and cement pile. The study is focused on design theory and its test of vertical bearing capacity for composite foundation of mixed red clay and cement pile. A hyperbola method and its criteria are proposed for single cement-red clay pile by comparison of stress distribution, strain pattern and destruction property among single cement-red clay pile, single concrete pile and single composite foundation pile. Furthermore, an optimal design method is proposed for composite foundation of mixed cement-red clay pile by detailed study of pile size, pile location and bearing capacity calculation. Finally, a guideline is suggested for improvement of ground treatment technique and cost reduction of mixed cement-red clay pile.