干湿循环作用下崩岗土体抗拉强度的衰减性分析

针对干湿循环影响下崩岗土体崩壁出现失稳等问题,通过开展室内单轴抗拉试验,研究了湖北通城地区不同干湿循环作用下崩岗土体抗拉强度的变化规律。结果表明:崩岗土体的抗拉强度随着干湿循环次数的增加逐渐衰减,最后逐渐趋于稳定,且不同层次土壤的抗拉强度衰减主要集中在前3个干湿循环周期,表土层、红土层、过渡层和砂土层抗拉强度衰减比例分别达到90%,82%,83%,90%,且不同层次土壤的抗拉强度总体表现为过渡层>红土层>表土层>砂土层。并通过考虑崩岗不同层次土体深度和干湿循环次数的共同影响,建立了抗拉强度衰减预估模型,且抗拉强度模型预测值与实测值有较高的相关关系(R^2=0.97),该模型对研究崩岗不同层次土体抗拉强度衰减机制具有指导意义。

Analysis of Attenuation of Tensile Strength of Collapsing Soil Under the Action of Dry and Wet Cycles

Aiming at the instability of the collapsing gully wall under the influence of dry-wet cycling, we studied the change rule of the tensile strength of the collapsing soil under the different dry and wet cycles in Tongcheng area of Hubei Province through the indoor uniaxial tensile test. The results showed that the tensile strength of the collapsing soil gradually decreased with the increasing of the number of dry-wet cycles, and finally tended to be stable, and the attenuation of tensile strength of different layers of soil mainly concentrated on the first three dry-wet cycles.The attenuation ratio of tensile strength of topsoil, laterite, transition layer and sandy soil layer reached 90%, 82%, 83% and 90%, respectively, and the tensile strength of different layers of soil followed the order of transition layer > laterite layer > topsoil layer > sandy layer. By considering the influence of the depth of different layers and the number of dry-wet cycles, the prediction model of tensile strength attenuation was established, and the prediction value of tensile strength model had a high correlation with the measured value (R²=0.97). The model had guiding significance for the study of the attenuation mechanism of tensile strength of different layers of soil.