砒砂岩遇水失稳对公路影响试验研究

在甘肃陇东地区G327线镇原至王咀子段部分区段存在典型的砒砂岩-黄土二元地质结构，遇水后会产生失稳变形。为研究该变形对公路的影响，利用室内模型，测量了不同上覆荷载和不同含水率下的砒砂岩位移，并进行了砒砂岩崩解试验。结果发现：砒砂岩在自然状态下强度较高，遇水后变形量逐渐增加，达到一定值后迅速失稳破坏，从而引起上部黄土失稳变形；由此引起的路基变形、路面残留堆积物，对整个公路施工及后期运行均会产生严重影响。因此在此类公路修建过程中，应通过采用封堵顶部黄土层中发育的落水洞、支护黄土-砒砂岩二元结构的坡面并在底部设置截排水沟的工程措施，来防止砒砂岩-黄土二元结构的变形失稳，确保公路安全运行。

Experimental Study on Influence of Water-induced Instability of Arsenic Sandstone on Highway

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.