粗粒土非线性强度切线参数的原理与确定

Principle and Determination of Non-linear Tangent Strength Parameter for Coarse Grained Soil

粗粒土的强度具有明显的非线性,本文在大型单剪仪的试验基础上分析了粗粒土非线性强度机理,认为强度非线性意味着强度参数的非线性,阐述了用切线参数描述强度非线性的原理,切线参数cσ、tanφσ都随法向应力σn变化。根据强度理论和数学原理提出了非线性强度的切线参数确定方法,针对某一法向应力的抗剪强度仍然可用线性库伦公式这一基本形式表达,而不用改变强度理论先前的运用原理。实例表明,切线参数的确定方法和非线性强度的计算不存在理论误差。虽然主要讨论粗粒土,但期望思路和方法可应用于具有强度非线性性质的其他土类。

Nonlinear strength is a natural property of coarse grained soil. The non-linear mechanism of coarse grained soil strength is analyzed based on large simple shear apparatus. It is illustrated that the non-linear strength predicates non-linear character of the strength parameter and the principle of nonlinearity is described by tangent strength parameter. The tangent strength parameter cσand tanφσare affected by normal stress. According to the strength theory and mathematic principle,the determination method of tangent strength parameter is proposed. As far as a certain normal stress is concerned,the shear strength can be expressed by tangent strength parameter and Mohr-Coulomb criterion,in doing this,it is unnecessary to modify the old strength theory. The instance indicates that the tangent strength parameter can be determined without theoretical error. Although in the paper only the coarse grained soil is discussed,the thoughts and the methods can be used in other soil with non-linear strength properties.