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| 有效应力方程的物理基础 |
| The physical basis of the effective stress equation |
| 投稿时间：2025-10-24 修订日期：2025-11-25 |
| DOI： |
| 中文关键词: 有效应力方程 岩土力学 孔隙介质力学 抗剪强度 变形 |
| 英文关键词:Effective stress equation, geomechanics,poromechanics, shear strength, deformation. |
| 基金项目: |
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| 摘要点击次数: 36 |
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| 中文摘要: |
| Terzaghi关于有效应力的概念和有效应力方程对岩土和孔隙介质力学具有奠基性的意义。但是由于有效应力的物理意义不明确、有效应力方程的导出没有理论依据,因此自提出以来一直存有争议,焦点是(1)有效应力是什么？它是真实的还是虚拟的物理量？(2)有效应力方程是否需要修正？(3)非饱和状态下是否存在决定土的抗剪强度和变形的有效应力？本文从土中一点的内力分析出发,首先分析孔隙流体压强作用产生的骨架应力,再基于内力的合力等于骨架与孔隙面积上的内力之和直接推导出饱和与非饱和土的有效应力方程。由此揭示了有效应力的物理意义和有效应力方程的物理基础：有效应力是不包含孔隙流体压强的所有其他外荷载作用产生的土骨架应力(称为外力骨架应力)；有效应力方程表征的是土体内力的合力与分力之间的关系,它自然成立,无需验证,也无需修正。土的抗剪强度和变形就是土骨架的抗剪强度和变形。土骨架的强度和变形当然与骨架应力有关,而骨架应力被分成了孔隙流体压强和有效应力两部分,因此,在孔隙流体压强对抗剪强度和变形的贡献可以忽略的情况下,有效应力控制土的抗剪强度和变形。 |
| 英文摘要: |
| The concept of effective stress and the corresponding effective stress equation hold fundamental significance in geomechanics and poromechanics. However, there has been ongoing controversy regarding the effective stress equation due to varying interpretations of effective stress. The main issues of the controversy are: (1) What the effective stress is and is it a real physical quantity or a virtual one? (2) Whether the Terzaghi"s effective stress equation needs to be modified? (3) If there is an effective stress that controls the shear strength and deformation of the soils in unsaturated state? This paper highlights that once the pore fluid pressure and other external load effects are considered separately, the effective stress equation can be theoretically derived directly for both saturated and unsaturated soils. The derivation clarifies that the effective stress represents the soil skeleton stress generated by all external forces except pore fluid pressure, which can be called as external load-induced skeleton stress. It also clarifies that the effective stress equation is an expression of the relationship between the resultant and component of the internal forces on any elementary plane of a soil. It holds true naturally, and thus requires no experimental verification or theoretical dispute. The shear strength and deformation of soil are practically those of the soil skeleton, they are naturally related to the stress of the skeleton. Since the stress of the soil skeleton is divided into two parts, i.e. pore fluid pressure and the effective stress, the latter controls the shear strength and deformation of soil in the cases of the contribution of pore fluid pressure to the shear strength and deformation can be neglected. |
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