全风化泥质粉砂岩性质介于土、岩之间,因其在交通循环荷载作用下的长期沉降较软土要小,常被视为岩类材料进而在累积变形问题方面的研究较少。但经调研发现,风化程度高的软岩对地铁盾构隧道等变形敏感的结构影响很大。因此,有必要对全风化泥质粉砂岩的力学性质进行更深入的探究。通过分析该岩样在不同试验条件(固结方式、水渗透作用、不同围压)下的不排水静剪切强度,绘制破坏应力线,研究该岩样的结构特性。结果表明:K0固结下的岩样破坏偏应力和孔压峰值均高于等向固结,说明固结方式对全风化泥质粉砂岩的应力应变和孔隙水压力有着显著的影响;在同一试验条件下,试样的破坏偏应力和孔压峰值随着固结围压的增加而线性增长;经过水渗透处理后的岩样,有效应力减小,抗剪强度降低,破坏程度加剧。
The properties of completely weathered argillaceous siltstone are between soil and rock. Due to its long-term settlement under traffic cyclic load is smaller than that of soft soil, it is often regarded as rock material and thus has less research on cumulative deformation. However, after investigation, it is found that the highly weathered soft rock has a great influence on the deformation-sensitive structures such as subway shield tunnel. Hence, it is necessary to conduct a more in-depth study on the mechanical properties of completely weathered argillaceous siltstone. By analyzing the undrained static shear strength of the rock sample under different test conditions (consolidation mode, water infiltration, and different confining pressure), and drawing the critical state line, the structural characteristics of the rock sample are understood. The results show that: The failure deviatoric stress and peak pore water pressure of rock sample under K0 consolidation are higher than those under isotropic consolidation, indicating that the consolidation mode has a significant effect on the stress-strain and pore water pressure of the completely weathered argillaceous siltstone. Under the same test conditions, the failure deviatoric stress and peak pore water pressure of the samples increases linearly with the increase of the consolidation pressure. After water infiltration treatment, the effective stress of the rock sample decreases, the shear strength reduces, and the degree of damage intensifies.
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