基于试验与模型的构树根系固土效果量化的研究

doi:10.16843/j.sswc.2019.01.004

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Abstract [Background] Roots of vegetation play an important role in slope stability, and increase soil strength. To study and quantify the effect of the root system on soil reinforcement, taking the Broussonetia papyrifera as the research object, the reinforcement effect of the root system of the B. papyrifera was determined by two methods of experimental determination and model calculation.[Methods] We used root-soil samples of B. papyrifera with different root diameters and volumes, and measured the pull strength of root-soil samples. Direct shear instrument was used to determine the shear strength of the root-soil and soil blocks. Wu model was to calculate the root shear strength increment of the root-soil samples. Compared measured values with the calculated values by Wu model, the effect of the diameter and the number of roots on the increment of shear strength were analyzed.[Results] 1) The tensile strength and pull strength of B. papyrifera root decreased with the increase of diameter. Two strengths intersected at a diameter of 1.3 mm. The root's pull strength was greater than the tensile strength when the diameter was < 1.3 mm; the tensile strength was higher than the pull strength when the root system was > 1.3 mm. 2) The results of the direct shear test showed that when the positive pressure on the shear surface was smaller, the shear strength of the soil-root blocks increased with the increase of the root diameter and the number of roots. As the positive pressure increased, the relationship between the shear strength and root diameter and the number of roots was no longer a simple incremental relationship. The maximum shear strength of root-soil complexes with the same number of roots migrated toward the smaller diameter of the average root diameter. 3) Wu model overestimated the effect of roots on soil reinforcement, and high valuation increased as the number of roots and root diameter increases.[Conclusions] There is a threshold between the tensile strength and the pull strength, and it is 1.3 mm. Under a certain range of root cross-sectional area ratio, the influence of the increase in shear strength of smaller diameter roots is more significant than the number of roots. For soil of Jiufeng and the root of B. papyrifera, we revised the k' value as 0.45. In addition, how to improve the simulation accuracy of the model and explore the numerical model of strength suitable for the failure of different plant roots is still a direction in this field.

Key words： Broussonetia papyrifera reinforcement effect tensile and pull strength enhancement value of shear strength Wu model

Received: 16 May 2018

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S714

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	Articles by authors
	BO Shengnan
	WANG Yunqi
	MA Chao
	LI Yaguang

Cite this article:

BO Shengnan,WANG Yunqi,MA Chao, et al. Quantified effects of fixing soil by root system of Broussonetia papyrifera based on experiment and model[J]. SSWC, 2019, 17(1): 24-30.

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http://journal12.magtechjournal.com/Jweb_stbc/EN/10.16843/j.sswc.2019.01.004 OR http://journal12.magtechjournal.com/Jweb_stbc/EN/Y2019/V17/I1/24

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