花岗岩残积土由于强度较高,常常用于高速公路路基的填方,但花岗岩残积土具有较强的渗透性,抗冲刷能力较差,在多雨季节施工,雨水冲刷会对填方质量产生较大的影响。通过对不同红黏土掺量的花岗岩残积土进行渗透试验和无侧限抗压强度试验,研究红黏土掺量对花岗岩残积土的渗透系数和无侧限抗压强度的影响趋势;在室内试验的基础上选取具体工程进行填方对比试验。研究结果认为:花岗岩残积土的渗透系数随着红黏土掺量的增加而减小;无侧限抗压强度随着红黏土掺量的增加而增大;花岗岩残积土中红黏土的最优掺量是40%,具体工程中采取2车花岗岩残积土加1车红黏土的“3+2”混合填料法能达到较好的填方效果。研究结果为花岗岩残积土地区工程建设的基础材料填筑与加固提供参考。

Granite residual soil is often used in the filling of highway roadbed because of its high strength; nevertheless in rainy season, the quality of filling would be affected markedly by rainfall due to granite residual soil's strong permeability and poor anti-scour ability. By adding red clay into granite residual soil, the influence of red clay content on permeability coefficient and unconfined compressive strength of granite residual soil was examined via permeability test and unconfined compressive strength test. On the basis of indoor test, comparative study was also carried out with specific filling project. Results revealed that with the increasing of red clay content, the permeability coefficient of granite residual soil declined while unconfined compressive strength augmented. The optimum content of red clay in granite residual soil is 40%. In actual project, two vehicles of granite residual soil mixed with one vehicle of red clay could achieve good filling effect. The research findings could be references for the filling and reinforcement of project construction in granite residual soil area.