单侧穿越溶洞嵌岩双斜桩的双向受荷模型试验研究

    Model test study on bidirectional load-bearing behavior of double inclined rock-socketed piles unilaterally traversing karst cave

    • 摘要: 目前对复杂岩溶地质条件下的嵌岩双斜桩承载特性研究匮乏。考虑嵌岩双斜桩单侧穿越溶洞的复杂工况,针对斜桩倾角、溶洞洞径和溶洞顶板厚度,设计8组竖向定荷载下单侧穿越溶洞嵌岩双斜桩的水平受荷模型试验,试验结果表明:低竖向荷载下的双斜桩系统承载能力差异性较小,仅在穿越6d较大溶洞洞径时,沉降增大37.8%,伴随屈曲破坏风险出现;桩身倾角对竖向定荷载下的桩基水平承载力提升较为明显;岩溶顶板安全厚度约为2d,低于此界限时桩基水平承载能力急剧下滑;大溶洞洞径和薄溶洞顶板厚度会使双斜桩系统由桩身受弯失稳转变为持力层失效的破坏模式。

       

      Abstract: Research on the bearing capacity characteristics of double inclined piles embedded in rock with karst geological conditions is limited. Eight groups of model tests are designed to investigate the horizontal-load bearing characteristics under constant vertical loading for double inclined piles considering the complex situation where double inclined piles unilaterally through a karst cave focusing on variable include pile inclination angle, cave diameter, and cave roof thickness. The test results indicate that the bearing capacity of the double inclined pile system shows minimal variation under low vertical loads, with settlement increasing by 37.8% only when passing through a larger cave diameter of 6d, accompanied by the risk of buckling failure. The pile inclination angle significantly enhances the horizontal bearing capacity of the pile foundation under constant vertical loading. The safe thickness of the karst cave roof is approximately 2d, below which the horizontal bearing capacity of the pile foundation decreases quickly. The double inclined pile system failure mode of bending instability of the pile shaft would convert to instability of the bearing stratum by large cave diameters and thin cave roof thickness.

       

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