Study and Analysis on Pile-Soil Stress Ratio of the Composite Foundation of Cement-Soil Mixing Pile under Flexible Foundation

In order to analyze the characteristics of pile-soil stress ratio of the composite foundation of cement-soil mixing pile under flexible foundation, this paper points out the displacement mode of friction pile; According to the deformation characteristic of friction pile, ascertain the neutral point of composite foundation. And this paper also derives the exact formula about length-stress ratio which addresses the problem of soft soil foundation according to the deformation co-ordination conditions of the pile composite foundation. The calculation of actual example proves that the formula about pile-soil stress ratio is in accordance with actual measurement number. The pile-soil stress ratio which addresses the problem of soft soil foundation is generally between 2~4. If other conditions keep invariable, pile-soil stress ratio become big when cushion modulus become big. Cushion modulus effect the length-stress ratio greatly.