基于非线性Mohr–Coulomb破坏准则的浅埋倾斜条形锚板抗拔承载力预测

Prediction of Uplift Capacity of Shallow-Buried Inclined Strip Anchor Plate Based on Nonlinear Mohr-Coulomb Failure Criterion

针对浅埋倾斜布置条形锚板抗拔承载力预测问题,本文采用非线性Mohr–Coulomb破坏准则,提出了极限上拔荷载作用下锚板上方土体的非对称曲线型破坏机制,并利用极限分析上限法与虚功率原理,导出了浅埋倾斜条形锚板极限抗拔力和土体破裂曲线的理论解析解。在此基础上,分析得到了埋深比、布设倾角、非线性系数、初始黏聚力、土体重度和地面超载等参数对锚板极限抗拔力和土体破裂范围的影响规律。研究结果显示:锚板极限抗拔力随布设倾角、埋深比、土体初始黏聚力、重度与地面超载增加而增大,但随非线性系数增加而减小;土体破裂范围随非线性系数和土体重度增加而减小,随初始黏聚力和地面超载增加而增大;锚板倾角、埋深比、土体黏聚力与非线性系数对倾斜条形锚板极限抗拔力和土体破裂范围影响较为显著,在工程设计及施工中应予以重视。将本文结果和现有研究工作进行对比分析,本文方法计算求得的锚板极限抗拔力及土体破裂范围与已有研究方法成果具有较好的吻合特性,进一步验证了本文方法的有效性。本文研究工作可为条形锚板设计及施工提供一定理论参考。

Aiming at the prediction of the uplift capacity of shallow-buried inclined strip anchor plates, the nonlinear Mohr-Coulomb failure criterion was employed in the analyses, and an asymmetric curve failure mechanism of the soil mass above the anchor plate in a limit state was proposed. Then based on the upper bound method and the principle of virtual power, the analytical solutions for the ultimate pullout force of the anchor plate and the soil failure curve were deduced. On this basis, the influence laws of buried depth ratio, inclination angle, nonlinear coefficient,initial cohesion, unit weight, and ground overload on the ultimate pullout force and soil failure range were obtained. The results show that the ultimate pullout force of the anchor plate increases with the increase of inclination angle, buried depth ratio, initial cohesion, unit weight, and ground overload, but decreases with the increase of nonlinear coefficient. The failure range of the soil mass decreases with the increase of nonlinear coefficient and unit weight but increases with the increase of initial cohesion and ground overload. The inclination angle, buried depth ratio of the anchor plate and the initial cohesion, and nonlinear coefficient of the soil mass have a significant influence on the uplift capacity and failure range,and more attention should be paid to engineering design and construction. Finally, a comparison analysis with existing research works was conducted. The ultimate pullout force and the failure range of the anchor plate obtained by this method are in good agreement with the results of existing research methods, which further verifies the effectiveness of the proposed method. The research work can provide some theoretical references for the design and construction of strip anchor plates.