In order to study the effect of climate and environment on the performance of loess Road

the CBRvalues of soil samples under dry and wet cycle and freezing thawing cycle were measured by indoor CBRtest.The relationship between P-Lcurves

cycle times and CBRvalues under different cycle conditions

and the evolution law of water content and CBRvalue were analyzed.The experimental results showed that:（1）the relation of P-LIn a curve

when the number of cycles is fixed

the penetration amount increases with the increase of unit pressure.Under the same unit pressure

the more the cycle times

the lower the strength of the specimen and the greater penetration.（2）during the 5 dry and wet cycle

the CBR value decreases with the increase of the cycle times.The CBRvalue under the dry and wet cycle is negatively correlated with the cycle times

the second dry wet cycle is a turning point

the decrease of the CBRvalue increases gradually

and the characteristics of the matrix suction and pore structure are interrelated under the action of repeated dry and wet cycles.（3）during the freeze-thaw cycle

the CBRvalue of freeze-thaw cycles was negatively related to the number of cycles two times

and tended to be stable.（4）in the process of repeated cycles

the change rules of the analysis can be used to simulate the long-term evolution of the Loess Subgrade under the influence of climate and environment

and provide some reference for the actual working conditions.