不同厚度溶洞顶板与基桩作用机理室内模型试验研究

发布时间：2018-12-10 20:17

【摘要】：根据相似理论,设计了3组不同厚度条件下溶洞顶板破坏模式的大比例模型试验,得到了顶板和基桩的荷载-位移曲线、顶板底部的极限应变曲线和不同厚度条件下溶洞顶板的破坏特性。试验结果表明:当溶洞顶板厚度为1d,2d时,发生冲切破坏,冲切体为圆台;当溶洞顶板厚度为3d时,顶板则以弯拉破坏为主,无冲切体产生。在荷载-位移曲线中,线性阶段转变为非线性阶段的临界点约为极限承载力的一半。最后通过理论计算的方法,获得溶洞顶板最小安全厚度计算公式,分析结果与试验结果吻合较好,能满足工程计算精度要求。本文试验成果是基于工程最不利情况得出的,可供岩溶区基桩初步设计参考。
[Abstract]:According to the similarity theory, three groups of large scale model tests of roof failure mode of karst cave under different thickness conditions are designed, and the load-displacement curves of roof and pile are obtained. The limit strain curve at the bottom of the roof and the failure characteristics of the cavern roof under different thickness conditions. The experimental results show that when the thickness of the roof of the cave is 1 day or 2 days, the punching failure occurs and the punching body is a round platform, and when the thickness of the roof of the cave is 3 days, the roof of the cave is mainly caused by bending and tensile failure, and no punching body is produced. In the load-displacement curve, the critical point at which the linear phase is transformed into the nonlinear stage is about half of the ultimate bearing capacity. Finally, the formula for calculating the minimum safe thickness of cavern roof is obtained by theoretical calculation. The analytical results are in good agreement with the experimental results and can meet the requirements of engineering calculation accuracy. The experimental results obtained in this paper are based on the most disadvantageous conditions of engineering and can be used as reference for the preliminary design of foundation pile in karst area.
【作者单位】：湖南大学岩土工程研究所;
【基金】：国家自然科学基金项目资助(51278187)
【分类号】：TU473.1

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