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为探讨南宁非饱和弱膨胀土强度,寻求一种基于物理力学参量简化的强度方程。以弱膨胀土非饱和特性变化规律为依托,开展击实试验、自由膨胀率试验,三轴试验和膨胀力试验等一系列室内试验,获得了不同含水率下的吸附强度与膨胀力间的变化关系。结果表明:抗剪强度随含水率增加而减小,膨胀力与吸附强度变化关系可用指数函数形式表征。基于试验成果,从土的含水率与吸力出发,以膨胀力为变量,建立吸力作用下的预测模型,探索出一种改进的南宁弱膨胀土的强度预测方程。该方程能很好的预测抗剪强度,为非饱和强度理论分析提供一条新途径。
In order to investigate the strength of unsaturated weak expansive soil in Nanning, a simplified strength equation based on physical and mechanical parameters was proposed. Based on the variation of unsaturated expansive characteristics of weak expansive soil, a series of laboratory tests such as compaction test, free expansion test, triaxial test and expansive force test were carried out to obtain the change of adsorption strength and expansive force under different water contents relationship. The results show that the shear strength decreases with the increase of water content, and the relationship between swelling force and adsorption strength can be characterized by exponential function. Based on the experimental results, starting from the soil moisture content and suction, taking the expansive force as a variable, a prediction model under the action of suction is established, and an improved prediction formula of the strength of weak expansive soil in Nanning is explored. The equation can predict the shear strength well and provide a new way for the theoretical analysis of unsaturated strength.