Abstract:In some sections of the G327 Line from Zhenyuan to Wangzuizi in the Longdong region of Gansu Province, there is a typical binary geological structure of arsenic sandstone-loess, which may cause the instability and deformation after contact water. To study the impact of this deformation on highways, the indoor models are used to measure the displacement of arsentic sandstone under the different overlying loads and different water contents, and the arsenic sandstone disintegration tests are conducted. The results showe that the strength of arsenic sandstone is higher in the natural state and the deformation gradually increases after contacting water. After reaching a certain value, it quickly loses stability and fails, thus leading to the instability and deformation of the upper loess. The deformation of the roadbed and the residual accumulation on the pavement caused from this will have a serious impact on the entire highway construction and later operation. Therefore, in the construction process of such highways, the engineering measures should be taken to prevent the deformation and instability of the arsenic sandstone-loess binary structure by blocking the water holes developed in the top loess layer, supporting the slope surface of the loess-arsenic sandstone binary structure, and setting the interception and drainage ditches at the bottom in order to ensure the safe operation of the highway.
