(1) To understand the tree root-soil interaction under lateral and moment loading using a physical modelling technique; (2) To detect the possible factors (e.g. root architecture, water condition, and stress level) influencing a tree’s push-over behaviour; (3) To identify suitable scaling laws to use in physical modelling. Two 1:20 scaled root models with different architectures (namely, deep and narrow, and shallow and wide) were reconstructed and 3D printed based on the field-surveyed root architecture data. Push-over tests were performed both in elevated-gravity (centrifuge 20-g) and normal-gravity (1-g) conditions. The shallow and wide model showed higher anchorage strength than the deep and narrow model. Regardless of the root architecture, the root anchorage strength measured from dry soil was higher than that from saturated soil. However, once the effective stress was the same, regardless of water conditions, the root anchorage strength would be the same. The presence of water decreasing the soil effective stress and key lateral roots extending along the wind direction play a significant role on a tree’s push-over resistance. Centrifuge tests showed comparable results to the field pull-over measurements while 1-g model tests overestimated the root-soil interaction, which could be corrected for soil strength by using modified scaling laws.

中文翻译：

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侧向荷载作用下树木根土相互作用的小尺度建模

(1) 使用物理建模技术了解横向和力矩载荷下的树根-土壤相互作用；(2) 检测影响树木推倒行为的可能因素（例如根系结构、水分状况和压力水平）；(3) 确定适用于物理建模的缩放定律。基于实地调查的根结构数据重建和 3D 打印了两个具有不同结构（即深而窄、浅和宽）的 1:20 比例的根模型。Push-over 测试在高重力（离心机 20-g）和正常重力（1-g）条件下进行。浅而宽的模型比深而窄的模型表现出更高的锚固强度。无论根系结构如何，干土测量的根系锚固强度高于饱和土壤。然而，一旦有效应力相同，无论水体情况如何，根系锚固强度都相同。水的存在降低了土壤的有效应力，关键的侧根沿风向延伸，对树木的抗压能力起着重要作用。离心机测试显示出与现场牵引测量相当的结果，而 1-g 模型测试高估了根 - 土壤的相互作用，可以通过使用修改后的缩放定律对土壤强度进行校正。