[Objective] The effects of rock fissure angle on the in-situ shear characteristics of the base material under different plant root systems were studied

in order to provide a scientific reference for water and soil conservation and ecological restoration.[Methods] The samples were cured for 90 days under three conditions:plant-free

bermudagrass and multi-flowered magnolia. The in-situ shear test of the substrate was carried out under the angle of 15°

30°

45°

60°

75° and 90° between the rock crack and the vertical direction of shear.[Results] ①The shear strength and residual shear strength of bermudagrass and magnolia root-substrate composites were significantly greater than those of non-rooted substrates. The average increase in shear strength was 33.87%-65.18% and 44.94%-73.65% respectively. ② The shear strength of samples without plant substrate reached the peak value when the displacement was 8-11 mm

while the bermudagrass root-substrate composite and the multifloral magnolia root-soil composite reached the peak value when the displacement was 20-36 mm. The root system could lag the peak displacement of the vegetation concrete

and root-containing substrate sample could withstand greater deformation. ③ For the same plant

different distribution of rock fissures had different effects on the soil consolidation ability of the root system. As the fissure angle increased

its shear strength increased first and then decreased. When the fissure angle was 60°

its shear strength reached maximum.[Conclusion] The root system can significantly enhance the shear strength of the vegetation concrete substrate and increase the residual shear stress. The distribution of different cracks has different effects on improving the shear strength of the substrate

but the effect of crack distribution on residual shear strength is not obvious.