根-土复合体的三轴试验及其强度分析

Triaxial test and strength analysis of root-soil composite

植被根系对土体的强度有显著影响。现有研究缺乏准确的模型描述根-土复合体破坏时应力状态。为量化植被根系对土体强度的贡献,采用一系列固结不排水三轴试验研究了含根量对根-土复合体强度特征的影响,并基于能量耗散原理建立了根-土复合体强度预测模型,最后对比分析了试验结果与模型预测值。结果表明:根系可显著提高根-土复合体强度,当含根量为0.486%,根-土复合体的偏应力较素土增大了1.70倍,抗剪强度较素土提高了72.1%,围压较小时根系对土体强度的提高更为显著;根-土复合体内摩擦角随含根量的增加变化较小,而根-土复合体的黏聚力随含根量的增加而逐渐增大;根-土复合体模型预测值与试验结果较为接近,表明该模型具有较高的准确率和可靠度。研究成果可为根-土复合体强度特性理论研究提供参考,并为根-土复合体强度预测提供了可靠方法。

The root system of vegetation has a significant effect on soil strength.The existing studies lack an analytical description of the stress state during root-soil complex failure.To quantify the contribution of vegetation roots to soil strength,a series of consolidated undrained triaxial tests are conducted to study the strength characteristics of the root-soil composite,and a root-soil composite strength prediction model is established based on the energy dissipation principle.Finally the experimental results and the prediction model are compared and analyzed.The results show that the root system can significantly improves the strength of root-soil composite,when the root concentration is 0.486%,the deviatoric stress of the root-soil composite increases by 1.70 times compared with the plain soil,and the shear strength increases by 72.1%compared with the plain soil,and the root system significantly improves the strength of the soil more when the confining pressure is lower.The internal friction angle of the root-soil complex varies less with the increasing root content,while the cohesion of the root-soil complex gradually increases with the increasing root content.The predicted values of the root-soil complex model are close to the experimental results,indicating that the model is of high accuracy and reliability.The research results can provide a reference for theoretical studies on the strength characteristics of root-soil composites and provide a reliable method for predicting the strength of root-soil composites.