肋板式锚杆挡土墙构件强度可靠性与岩土参数随机性影响分析

Analysis of the Influence of Geotechnical Parameter Randomness on the Strength Reliability of Rib-Plate Anchor-Retaining Wall Components

摘要: 肋板式锚杆挡土墙的受力状态受墙后岩土参数影响显著，而实际岩土参数具有一定随机性。本文以普通肋板式锚杆挡土墙为研究对象，将土体重度、黏聚力和内摩擦角作为基本随机变量，建立主动土压力向面板、肋柱及锚杆连续传递的可靠度计算模型，并基于JC验算点法分析面板受弯、肋柱受弯、锚杆杆体受拉和锚固段抗拔4种失效模式的可靠水平及岩土参数变异性的影响。研究表明：基准工况下，肋柱受弯可靠指标为3.62，是挡墙的控制失效模式；面板受弯可靠指标为4.27，锚杆杆体受拉和锚固段抗拔可靠指标均大于7，具有较高的安全储备。内摩擦角对各失效模式可靠度的影响最大，黏聚力次之，土体重度相对较小。岩土参数离散程度增大会显著降低体系可靠度，且肋柱受弯始终为控制失效模式；当黏聚力变异系数不超过14%时，体系控制可靠指标可维持在3.2以上；对比不同墙高可知，岩土参数敏感度与挡墙高度呈正相关，控制失效指标也随墙高增加从肋柱变为面板。研究结果可为肋板式锚杆挡土墙的可靠度评价与设计提供依据。

Abstract: The mechanical response of ribbed anchored retaining walls is strongly affected by geotechnical parameters behind the wall, which exhibit inherent randomness. In this study, a conventional ribbed anchored retaining wall is investigated. Soil unit weight, cohesion, and internal friction angle are treated as basic random variables, and a reliability model is established to represent the continuous transfer of active earth pressure to the facing panel, rib column, and anchors. The JC checking-point method is employed to evaluate the reliability of four failure modes, namely facing-panel bending, rib-column bending, anchor-tendon tension, and anchorage pullout, as well as the influence of geotechnical parameter variability. Results show that under the baseline condition, the reliability index of rib-column bending is 3.62, making it the governing failure mode; the index for facing-panel bending is 4.27, while those for anchor-tendon tension and anchorage pullout exceed 7, indicating substantial safety reserves. The reliability of all failure modes is most sensitive to the internal friction angle, followed by cohesion and soil unit weight. Increasing parameter variability markedly reduces system reliability, with rib-column bending remaining the governing mode. When the coefficient of variation of cohesion does not exceed 14%, the governing reliability index remains above 3.2. By comparing different wall heights, it can be observed that the sensitivity of geotechnical parameters is positively correlated with the height of the retaining wall; likewise, the control failure index also varies from the rib columns to the panel as the wall height changes. The results provide a basis for reliability assessment and design of ribbed anchored retaining walls.