动、静载环境下界面土直剪试验

Direct Shear Test of Soil Interfacial Layer Under Dynamic and Static Load

为了探究土体界面土的力学性质及其变化规律,以粉土、粉质黏土和碎石土作为试验材料,以法向应力大小、上下土层类型、界面处理方式、动载环境、静载环境和动载作用时长等作为试验变量因素,运用正交试验设计方法对不同类型的原状土和重塑土试样进行室内直剪试验,得到了土体界面土的剪力-位移本构曲线,根据曲线中的峰值抗剪强度计算出了能够反映界面土抵抗黏性破坏能力的黏结系数。试验结果表明:粉土的黏结系数小于粉质黏土;界面土的抗剪强度与上下土层的结合类型相关,界面土的粗糙度越大,界面土处的土体接触越充分,则界面土的力学性质越好;随着动载作用时间的增加,土体界面土的抗剪强度会有所下降;并且,界面土的力学性质与上下土层性质之间有一定的联系。

To explore the mechanical properties of soil interfacial layers and their change law, the silt, silty clay, and gravel soil were taken as the experimental material, and the normal stress, soil type, interface treatment, load type, and effective time of dynamic load were taken as test variable factors. By using the orthogonal experimental design method, the indoor direct shear test of different undisturbed and remolded soil samples were carried out, and the shear force-displacement constitutive curves of soil interfacial layers were obtained. The bond coefficient of the interfacial layer was calculated according to the peak shear strength in these curves, which is related to the ability of resisting distruction. The experimental results show that the bond coefficient of silt is smaller than that of silty clay, and the strength of the soil interfacial layer is related to the combination type of the upper and lower soil layers;The greater the roughness of the interfacial layer and the more adequate the soil contact, the better the mechanical properties of the interfacial layer;With the increase of the acting time of the dynamic load, the strength of the soil interfacial layer decreases;The mechnanical properties of the interfacial layer are connected with the properties of the upper and lower soil layers.