强风化云母片岩路基填筑结构优化及效果评价

Study on Filling Structure Optimization and Stability of Strongly Weathered Mica Schist Subgrade

为验证利用强风化云母片岩进行路基填筑的可行性,以栆阳至潜江高速公路新建填方路基工程为背景,通过室内试验测试、现场方案比选及理论模型沉降预测等方法,优化强风化云母片岩路基填筑结构,对路基填筑过程中和工后稳定性进行了预测和评价。研究结果表明:提出的“三夹二开山石渣”新型路基结构层,经检测可以达到路基填筑要求,破解了强风化云母片岩不能用于路基填料的工程难题;新型路基结构层中的石渣增强了土体的骨架支撑作用,路基沉降控制效果;通过路基现场试验段监测及建立的灰色理论模型沉降预测结果表明,新型云母片岩路基结构长期变形满足高速公路沉降控制要求,为类似路基工程施工提供了参考依据。

In order to verify the feasibility of subgrade filling with strongly weathered mica schist,taking the new filling subgrade project of Zaoyang to Qianjiang expressway as the background,the filling scheme of strongly weathered mica schist subgrade is optimized through indoor test,field scheme comparison and selection,FLAC3D finite difference numerical simulation analysis and theoretical model prediction,the deformation stability during and after subgrade filling is predicted and evaluated.The results show that the proposed new subgrade structure layer of“three sandwiches and two Kaishan rock slag”can realize the filling of strongly weathered mica schist subgrade.The stone slag in the new subgrade structure layer enhances the skeleton support of the soil,increases the subgrade stiffness,and significantly improves the subgrade settlement control effect and the subgrade slope safety factor.The monitoring of subgrade test section and the prediction results of the established grey theory model show that the long-term deformation of the improved mica schist subgrade meets the control requirements of Zaoqian expressway,it provides a reference basis for the construction of similar subgrade projects.