Experiment And Numerical Simulation Of Desiccation Cracking Of Farmland Soil Under The Influence Of Roots

Plant roots play a positive role in inhibiting soil desiccation cracking behavior.Studying the effect of roots on soil desiccation cracks will prevent the generation and development of cracks,and reduce their damage to soil-related constructions.At present,the research on the effect of roots on soil cracking mainly conducts laboratory experiments to analyze quantitatively the strengthening effect of roots on soil.However,there are few studies on the dynamic development of soil desiccation cracks under the influence of roots in nature,and the development of corresponding numerical model are rarely reported.This paper studies the behavior of soil desiccation cracking under the influence of roots from experimental research and model development,and explores the influence of crop roots on the pattern of soil desiccation cracks and the dynamic development of soil desiccation cracks under the influence of roots.The main research contents of this paper include:?Experimental research:A field experiment on soil desiccation cracking under the influence of roots was carried out,and the complete dynamic development of cracks were recorded by taking photos.The change of morphological characteristics and Minkowski density of soil desiccation cracks under the influence of roots with time were analyzed.The Minkowski density of desiccation cracks with different roots was compared,and the effect of roots on soil desiccation cracking was analyzed.?Model development:This paper proposed a numerical model to describe the process of desiccation cracking of soil in the presence of roots,which is based on a lattice of Hookean spring model proposed by Vogel et al.(2005b)and the conditional simulation technology in geostatistics.The model can reflect the strengthening effect of the roots on the soil.The model parameters were calibrated and verified by the field experimental results,and the model precision was evaluated.?Sensitivity analysis:Sensitivity analysis was carried out on the model parameters of the number of conditional critical strain locations n,the conditional critical strain value hc,the conditional critical strain position x and correlation length ?.The influence of parameter changes on the random field of critical strain,the pattern of simulated cracks and its Minkowski density was discussed.For a long time,scholars have done very little research on pattern of soil desiccation cracks under the influence of roots in nature,and there are even fewer studies on numerical models of soil desiccation cracking under the influence of roots.Therefore,the simulation and prediction of soil desiccation cracks under the influence of roots is a major difficulty in related fields such as soil science.The numerical model proposed in this paper uses a conditional random field to describe the spatial variation structure of the critical strain of the soil under the influence of the roots.The simulation results reproduce the morphological characteristics and dynamic development of the desiccation cracks of the farmland soil under the influence of the roots.The research results have initially realized the simulation and prediction of the process of soil desiccation cracking under the influence of roots.