双粒径填石路基空隙注浆加固结构特征分析

论述了石料排列方式对空隙的影响规律，明确理论石料配位数与空隙率的对应关系；对填石路基空隙结构特征展开分析，确定双粒径填石路基方案，按照经验公式计算获取不同粒径比对应理论空隙率和小粒径石料占比，并搭建了室内空隙率灌水法试验进行验证；通过水泥土浆注浆对填石路基进行加固，控制三种注浆方式，分别检测其抗压及抗弯强度用以表征填石路基结构性能。试验结果表明:6∶1粒径比对应空隙率较低，可减少注浆量；经验公式计算结果与室内空隙率灌水法试验结果相吻合；试件破坏主要源于石料脆断而非胶结破坏；通过埋管压力注浆方案进行注浆加固的填石路基试件强度最高，可比常规注浆提高18.9 %。

Characteristics Analysis of Void Grouting Reinforcement Structure of Double-grained Rock-filled Roadbed

The influence law of the stone arrangement on the void has been discussed, and the corresponding relationship between the theoretical stone coordination number and the void ratio has been clarified. The characteristics of the void structure of the rockfill subgrade has been analyzed. The double-particle size filling roadbed scheme has been determined, and the theoretical void ratio and the proportion of small particle size corresponding to different particle size ratio have been calculated according to the empirical formula, and the indoor void ratio irrigation test has been set up for verification. The rockfill subgrade has been strengthened by cement-soil grouting. The compressive strength and flexural strength of the rockfill subgrade reinforced by three grouting methods are tested respectively to characterize the structural performance of the rockfill subgrade. The test results show that: 6:1 particle size ratio corresponds to a lower void ratio, which can reduce the amount of grouting. And the results calculated by the empirical formula is consistent with the experimental results of void ratio irrigation method in laboratory. The failure of test specimen is mainly caused by brittle fracture of stone rather than cementation failure. The strength of rockfill roadbed reinforced by grouting with buried pipe pressure grouting is the highest, which is 18.9 % higher than that of conventional grouting.