Abstract:Peaty soil is a special regional soft soil. Structures with peaty soil foundations are prone to produce large postconstruction settlements, largely affecting their safety. Thus, it is crucial to study the settlement of peaty soil. The settlement can be divided into three parts, which are as follows: settlement caused by lateral deformation, settlement under the confined condition, and secondary consolidation settlement. Based on the Duncan-Zhang constitutive model, the relationship between compression modulus and secant modulus was established. Combined with the generalized Hooke's law derivation, the settlement caused by lateral deformation was determined. The compression moduli of soil were calculated by the e-p, e-lgp, and e-lnp curves, and the settlement under the confined condition was calculated using the layer-wise method. Furthermore, a high-pressure consolidation creep test was performed on peaty soil. The secant modulus was calculated by the Duncan-Zhang model concept, and the nonlinear correction was performed on the original five-element rheological model. Subsequently, the original and nonlinear models were modified by the introduction of the correction coefficient φs. The two modified models were utilized to fit the creep test curves, and it was found that the fitting effect of the modified original model was very poor; moreover, the correlation coefficients of the modified nonlinear model were all greater than 0.9 and a constitutive equation suitable for describing the creep of peat soil was also obtained. Lastly, the two modified models were used to calculate the secondary consolidation settlement with the layer-wise summation method. It was revealed that the settlement calculation results of the peaty soil are consistent with the actual experiment results, confirming the rationality of the calculation results as well as providing a calculation theory and a constitutive model to reflect the creep characteristics of peaty soil.
