循环荷载下红层泥岩路基土的变形特性研究

针对红层泥岩土这种特殊的粒类材料,通过动三轴试验研究其在循环荷载下的变形特性。根据累积变形曲线的发展趋势,把红层泥岩土的累积变形分为稳定型和破坏型,并分析了产生不同变形曲线的原因。引入了动应力水平的概念,由试验数据得到红层泥岩土的临界动应力水平为30%左右。用Monismith模型来分析红层泥岩土的累积变形,发现系数A的离散性很大,而指数b的离散性较小。考虑土的类型、应力状态和物理性质等主要影响因素,将系数A扩展为3个参数,分别反映上述影响因素,3个参数具有明确的物理意义且容易确定,便于模型的实际应用。

Study on Deformation Property of Red Bed Mudstone of Subgrade Under Cyclic Loads

As a special grain material,the deformation properties of red bed mudstone under cyclic loads were studied through dynamic triaxial test.According to the trend features of the strain curve,accumulative deformation of red bed mudstone could be divided into two types: stable and failure types,and the mechanisms causing two types were explained.After introducing the concept of dynamic stress level,the author acquires that the critical level of dynamic stress is about 30%.When applying the model of Monismith to analyze the accumulative deformation,it has been found that the coefficient A has a large discreteness,but the discreteness of exponent b is little.Further,considering the influences of soil types,stress state and physical properties,the author extended the coefficient A to three parameters,then the three parameters were able to reflect the influence factors mentioned above.The three parameters have clear physical meaning and easy to determine,with the convenience for practical application of the model.