Effect of multiple wetting and drying cycles on the macropore structure of granite residual soil

•The drying effect makes the connected macropores become poor, the wetting effect the macropore space and porosity increase after wetting.•The variation of connected pore porosity is larger than that of the porosities of the total and isolated pores.•The connectivity of pores decreases with an increasing number of wetting and drying cycles.•The connected macropores play a decisive role on the saturated hydraulic conductivity of granite residual soil.