Chaos is a kind of universal phenomenon of nonlinear system. On the basis of chaotic theory

chaotic characteristics of soft soil foundation deformation of the Pearl River Delta are discussed. Based on engineering characteristics and microstructure of soft soil

radical reasons of chaotic characteristics of soft soil deformation are analyzed; the qualitative analysis and quantitative analysis according to Lyapunov exponents of chaotic characteristic of soft soil deformation are discussed as well. The research results show that all of the maximal Lyapunov exponent ( ) of natural soft soil foundation and all kinds of composite foundation in Pearl River Delta are more than 0; therefore the deformation of soft soil foundation is chaotic. The chaotic theory offers a new effective way for study of soft soil and has broad application foreground in engineering fields.