屈讼昭 郭咏华 王仪 张斌 张建明 孙清

摘 要：为研究大锚片螺旋锚在粉质黏土中竖向受压荷载下的受力性能，基于螺旋锚现场静载试验，讨论了确定其极限承载力方法的差异;考虑螺旋锚对周边土的挤压效应，建立精细化有限元模型，并将数值分析结果与试验结果进行对比，验证了有限元模型的合理性;基于验证的有限元模型，分析不同荷载等级下沿基础深度范围内的锚杆内力和侧摩阻力的变化规律，以及侧阻和锚片端阻承担荷载的比例关系。结果表明：用lg P-s方法确定大锚片螺旋锚基础极限受压承载力较合适;螺旋锚与土之间的摩阻力随下压位移的增加而增大，锚片附近区域的摩阻力由于锚片变形而发生较大的波动;螺旋锚锚片分担荷载的比例占据螺旋锚基础受荷的75%以上，各锚片间分担荷载比例最大差异约为6%，锚杆端阻可忽略不计。

关键词：螺旋锚;粉质黏土;现场试验;数值分析;极限承载力;受力性能

Abstract： In this paper， in order to study the mechanical performance of the screw anchor with large anchor pieces under vertical compressive load in silty clay， the differences of the methods to determine its ultimate bearing capacity based on the on-site static load test of the screw anchor have been discussed; Secondly， a refined finite element model considering the squeezing effect of the screw anchor on the surrounding soil has been established. And the numerical analysis results have been compared with the experimental findings to verify the rationality of the finite element model; Finally， based on the verified finite element model， the change pattern of the internal force and side friction resistance of the anchor within the depth range of the foundation under different load levels has been analyzed. The proportional relationship between the side resistance and the end resistance of the anchor plate to bear the load has been analyzed. The results show that the lg P-s method is suitable to determine the ultimate bearing capacity of the screw anchor foundation with large anchor pieces; The frictional resistance between the screw anchor and the soil increases with the increase of the downforce displacement. The frictional resistance of the area near the anchor plate fluctuates greatly due to the deformation of the anchor plate; The proportion of load shared by anchor pieces accounts for more than 75% of the load on the screw anchor foundation. The maximum difference in the load sharing ratio between the anchor pieces is about 6%， and the end resistance of the anchor foundation is negligible.

Keywords： screw anchor; silty clay; field tests; numerical analysis; ultimate bearing capacity; mechanical performance

螺旋锚基础是一种由螺旋锚和上部承台等构件组成，主要利用深层土体抵抗上部结构作用的锚固结构体。该基础以钢构件为主，施工工序少、施工简单，可显著减少或避免使用混凝土材料，从而极大程度上缩短施工周期。同时，螺旋锚施工时不必大范围开挖，地表破坏范围相对较小，环保效益明显，尤其对生态脆弱地区。此外，螺旋锚对土体的扰动小，能充分发挥原状土体固有强度，实现基础材料节省。鉴于螺旋锚基础的上述优点，工程中对其进行了一定的探索性应用[1-2]。……