植草根系的加筋效果及机理研究

Study on the effect and mechanism of grass roots reinforcement

为了研究植物根系对浅层土的加筋机理,对野外的巴根草根系原状粉土试样进行快剪试验,然后对剪切破坏后土样进行重塑,比较原状根系和重塑根系土样以及无根重塑土的抗剪特性,分析根系特性的加筋效果。研究结果表明根系对抗剪强度的影响随根须特征而改变,对于原状土样,当含根量少于0.2%时,根系的加筋作用不明显,当含根量在0.2%~1%时,含根原状土的抗剪强度明显提高。当含根量较多大于1%时,原状土的残余强度反而最低,这也说明根与土壤间的复杂生物化学作用对土体抗剪强度的提高起一定作用。

In order to study the reinforcement mechanism of plant roots on soil,the field undisturbed silt samplescontaining eleusine indica roots in the field were taken to fast direct shear test,and then the soil samples after shear failure were remolded.The shear properties of undisturbed roots,remolded roots and rootless remolded soil were compared,and the reinforcement effect of root characteristics was analyzed.The results show that the effect of root system on shear strength changes with the characteristics of root whiskers.For undisturbed soil samples,when the root content is less than 0.2%,the reinforcement effect of root system is not obvious.When the root content is between 0.2%and 1%,the shear strength of undisturbed soil with roots is significantly improved.When the root content is more than 1%,the residual strength of undisturbed soil is the lowest,which shows that the complex biochemical interaction between root and soil plays a certain role in the improvement of soil shear strength.