Understanding soil arching is an important component of predicting soil behaviour in cases such as the progressive displacements above sinkholes and when predicting loads on buried structures, where the expected deformation mechanisms are used to predict the applied loads. Visual validation of these deformation mechanisms above a void at appropriate stress levels remains limited. Centrifuge tests on dense sand were conducted to allow visualisation of the deformation mechanisms and hence enable a more accurate prediction of the load–displacement curve. The results showed that at the point of maximum arching a triangular failure zone corresponding to the formation of an apparent active failure wedge forms with proposed angles of 45° − ϕ_p/2 to the vertical. If the soil height is large enough to allow the full formation of this initial wedge, the deformation mechanism progresses to a vertical prism. Otherwise, the soil collapses into the void. A modification of the classical arching theory is required to allow it to be used to more accurately predict the stresses at the point of maximum arching and in the ultimate state with large displacements.

中文翻译：

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颗粒土中的拱形：变形机制的实验观察

了解土拱是预测土壤行为的一个重要组成部分，例如下沉洞上方的渐进位移和预测埋地结构上的载荷，其中预期的变形机制用于预测施加的载荷。在适当的应力水平下对空隙上方的这些变形机制的视觉验证仍然有限。对致密沙子进行离心试验，使变形机制可视化，从而能够更准确地预测载荷-位移曲线。结果表明，在最大拱形点处，三角形破坏区对应于明显的主动破坏楔形的形成，建议的角度为 45° -  ϕ _p/2 到垂直。如果土壤高度足够大，可以完全形成这个初始楔形，变形机制就会发展为垂直棱柱。否则，土壤会塌陷到虚空中。需要对经典拱形理论进行修改，使其能够更准确地预测最大拱形点和大位移最终状态下的应力。