基于平面应变模拟特征的钢棒相似土抗剪强度试验研究

Experimental Study on Shear Strength of Analogical Soil Based on Characteristics of Plane Strain Simulation

摘要: 为拓展土工模型试验技术手段，减少试验设备条件限制，本文针对可用于土工模型试验平面应变模拟的钢棒相似土材料，通过设计改造直剪仪开展了不同粒径级配条件下的直剪试验。结果表明，钢棒相似土受剪时类似于密砂，呈明显的应变软化现象，且峰值强度与上覆荷载及粒径级配密切相关，剪切特性符合库仑强度理论。由此，计算得到不同粒径级配工况下的钢棒相似土内摩擦角，建立了平均粒径与内摩擦角的数学关系。研究结论可用于平面应变条件下土工模型试验的设计与计算。

Abstract: In order to expand the technical means of geotechnical model test and reduce the limitation of test equipment, in this paper, the direct shear tests under different particle size gradations of analogical soil materials that can be used for plane strain simulation of geotechnical model test, are carried out by designing and modifying the direct shear apparatus. The results show that the analogical soil is similar to dense sand in shear, showing obvious strain softening phenomenon, the peak strength is closely related to the overlying load and particle size gradation, and the properties of shear conform to Mohr-Coulomb strength theory. Therefore, the internal friction angle of analog cal soil is calculated under different particle size gradations conditions, and the mathematical relationship between average particle size and internal friction angle is established. The research conclusion can be used for the design and calculation of geotechnical model test under plane strain condition.