Background Many dump yards are formed during backfilling earthwork. The soils were loose and soil nutrient was deficient in dump yards. Vegetation are widely used to reinforceside slope of dump yards. At present, the researches on soil fixation of side slope were mainly concentrated on highway slopes and reservoir slopes. Few reports were concentrated on side slope of stone dump yards.

Methods Compared with bare land of dump yards in Diexi town of Mao county, native herbs (Taraxacum mongolicum, Phragmites australis, Chenopodium album) and artificially planted herbs (Lolium perenne and Eleusine indica) were as the research objects. In order to screen out herbaceous plants with better performance in soil conservation and slope fixation, electronic universal testing machine, direct shear apparatus and soil anti-scourability experimental device were applied to measure the maximum tension resistance and tensile strength of single root, the shear strength of root-soil composite and soil anti-scourability index, respectively.

Results 1) The tensile resistance of herb roots increased with the increase of root diameter, whereas the tensile strength decreased with the increase of root diameter. The average root tensile resistance of five herbs presented as C. album (12.42 N)> T. mongolicum (11.52 N)> P. australis (7.96 N)> E. indica (4.36 N)> L. perenne (3.36 N), while the tensile strength showed an opposite trend as L. perenne(62.6 MPa) > E. indica(43.8 MPa) > P. australis(43.7 MPa) > T. mongolicum(32.2 MPa) > C. album(27.2 MPa). 2)The root-soil composite of L. perenne generally showed the highest shear strength, followed by E. indica, C. album, T. mongolicum, P. australis and bare land under 4 load conditions (level 50, 100, 150 and 200 kPa). 3) Soil anti-scourability indexes of five herbs presented as L. perenne(3.09 min/g)> C. album (2.93 min/g)> E. indica (2.60 min/g)> T. mongolicum (2.19 min/g)> P. australis (1.52 min/g)> Bare land (1.37 min/g).

Conclusions C. album showed maximum tension resistance of single root, and the L. perenne showed maximum anti-scourability and shear strength. Therefore, C. album and L. perenne should be considered invegetation restoration of dump yards in the barrier area of western Sichuan basin.