At present, the mechanical properties of a single type of soil are focused on in the studies, but the interaction between different types of soil under the condition of coexistence is ignored, and the study on the coordination between different types of soil still has a big gap. According to the needs of the actual engineering situation on site and to study the low liquid limit silty clay-sand strata, the standard triaxial experiment was used to study, in the coexistence of a large number of low liquid limit silty clay and sand strata, the effect of sand content and water content factors on the change of the strength of the strata, and the applicability of Duncan-Chang model. The results show that: compared with silty clay strata, the strength of low liquid limit silty clay-sand strata is smaller; The influence of sand content on soil strength in low liquid limit silty clay-sand strata is obviously divided; The influence of water content of low liquid limit silty clay-sand formation on soil strength is related to sand content and in-situ stress; The low liquid limit silty clay-sand strata accords well with Duncan-Chang hyperbola incremental elastic model.