Abstract: A unified analytical solution to cylindrical cavity expansion is derived by considering different ratio of tension modulus to compression modulus and strain-softening behavior. The stress field, strain field, displacement field and final expansion pressure are obtained. On the basis of this, the calculation formula of the limit bearing capacity of aggregate pile is obtained, and the formula is applied to calculate the limit bearing capacity of gravel pile in a highway gravel pile composite foundation. The calculation results agree well with the in situ measured values. In the end, the influence of different ratio of tension modulus to compression modulus, parameter of strain-softening behavior and other parameters on calculation results is discussed. The analysis results show that neglect of difference between the tension modulus and compression modulus and the strain-softening behavior will lead to significant calculation errors.