Based on the previous studies of others

the incremental calculation method is applied to the composite retaining system of cement-soil piles and soil nailing(CRSCSPSN). According to the unloading effect of excavation and the forming mechanism of soil-nail forces

the establishment method for the proportional coefficients of soil-nail forces is presented and the method makes it possible to calculate the soil-nail forces by increments. The incremental calculation method can effectively explain the influence of construction on soil-nail forces; and the calculation results of this method are more consistent with those of the measured. According to the deformation compatibility between the cement-soil piles and soil nails

and the relations between force and deformation both for soil nails and cement-soil piles

the simplified deformation calculation method for CRSCSPSN is presented. The deformation calculation method proposed is also based on the incremental theory. At last

there is an engineering case of which the calculated horizontal-displacement results and measured results are compared; and the comparison conclusions show that the simplified calculation method of horizontal displacements for CRSCSPSN is acceptable and effective.