Based on Coulomb’s earth pressure theory

assuming the trace of the principal stress arching in the back of rigid retaining wall as parabola

the theory formulae are obtained including the lateral coefficients of active and passive earth pressures and the friction coefficients of horizontal differential elements; then improved formulae of active and passive earth pressures are presented. The results show that the calculation results considering soil arching are consistent with the ones of model tests. Being in active limit state

the inner friction angles become smaller

the outer friction angles on the soil-wall interface become larger; the effect of soil arching becomes more distinct; as a result

the application point of resultant active earth pressure is higher. Being in passive limit state

the inner friction angles and the outer friction angles on the soil-wall interface are larger

the effect of soil arching becomes more distinct; and the application point of resultant passive pressures is lower.