粉土路基坡面复合面层护坡技术的面层材料特性

针对粉土路基边坡的坡面冲刷破坏和分层滑移破坏特征，提出一种融合玄武岩纤维加筋与聚丙烯酰胺固化作用，并集植草、抗冲刷、增稳多种功效的粉土路基坡面复合面层护坡技术。根据复合面层中不同面层的防护机制，开展对应面层材料的直剪试验、淋滤质量损失试验、渗透试验和毛细水上升试验，通过讨论面层材料中玄武岩纤维加筋量、筋长、聚丙烯酰胺掺量的变化与对应面层材料剪切变形、剪切强度、质量损失比、渗透系数、入渗量的关系规律，从材料角度分析获得玄武岩纤维的相对经济掺量、筋长与聚丙烯酰胺的相对经济配比及其对应材料指标。试验结果表明：复合面层材料相对粉土强度提高80%~150%，抗冲刷性能提高约200%，抗渗性提高约3个数量级；面层材料相对经济的配合比大致为玄武岩纤维筋长12 mm、掺量0.4%，聚丙烯酰胺掺量1%；面层材料大幅改善了原粉土的强度、变形性能、抗冲刷性与抗渗性，3层复合面层材料将减少入渗、削弱侵蚀、提高强度3种功能融为一体。

Surface Material Properties of Slope Surface Protection Technology with Composite Layers in Silt Subgrade

In allusion to failure characteristics of the slope surface erosion and the layered slipping of the silt subgrade, a new slope surface protection technology with composite layers was proposed by combining basalt fiber reinforcement and the polyacrylamide solidification, with function of planting grass, anti-scouring and improving soil strength. According to the protection mechanism of different composite layers, direct shear tests, leaching tests, permeability tests and capillary water rise tests were carried out. The variation of basalt fiber reinforcement modulus, length of basalt fiber and relative optimal dosage of polyacrylamide as well as relations of shear strength, shear deformation, quality loss ratio of soil, permeability coefficient and infiltration capacity was discussed. The relative economical dosage of basalt fiber, length of basalt fiber and relative optimum proportions of polyacrylamide were analyzed from the perspective of materials. The results show that compared with the natural silt, the strength of composite layers increases by 0.8 to 1.5 times. The performance of anti-erosion increases by about 200%, whilst the impermeability increases by three orders of magnitude. The relative optimal length of basalt fiber is 12 mm, and the relative optimal quality ratio is 0.4%. The relative optimal dosage of polyacrylamide is 1%. The surface layer material greatly has been used to improve the strength, deformation performance, erosion resistance and impermeability of the original silty soil. The strength of silt, anti-erosion resistance performance and impermeability performance of the silt can be significantly improved by dint of materials in three composite layers.