风积沙地基斜柱基础上拔水平力组合荷载试验

Full-scale tests on pad and chimney foundation subject to uplift combined with horizontal loads in aeolian sand

对不同埋深、不同底板宽度和不同露头高度的风积沙地基斜柱式扩展基础,在上拔与水平力组合荷载作用下的承载变形特性、基础底板与风积沙地基之间的接触压力变化规律开展现场试验研究。结果表明,由于风积沙地基的散体结构特性,上拔与水平力组合荷载作用下斜柱式扩展基础的强度机理可概括为:风积沙地基被压缩挤密-塑性区出现和发展-整体上拔破坏的渐进破坏过程,地基破裂面具有不对称性。水平荷载大小、深宽比及嵌固程度是决定斜柱式扩展基础抗拔承载力的重要因素,增加基础深宽比及嵌固程度可有效提高基础稳定性。

The in-site full-scale tests on the bearing capacity behavior of pad and chimney foundations sujected to uplift combined with horizontal loads in aeolian sand are done. All these pad and chimney foundations are of different embedment depths, widths of the bottom and different heights above the ground level. The progessive failure process can be described as ＂compression and compaction of aeolian sand--occurrence and further development of plastic zone in aeolian sand -- formation of rupture surface and entire damage of the aeolian sand subgrade＂. The horizontal load, the ratio of embedment depth to width of the bottom, the ratio of the height above ground level to embedment depth of the bottom are decisive factors to determine the uplift bearing capacity of the pad and chimney foundation. The rapture plane of the aeolian sand is of asymmetry property, which was different from the behavior of the foundation subject to uplift load only. The method of increasing the ratio of embedment depth to width of the bottom, the ratio of the height above ground level to embedment depth of the bottom can be used to enhance the bearing capacity of the pad and chimney foundations subjected to uplift combined with horizontal loads in aeolian sand.