浏醴高速公路红砂岩路基填筑现场试验研究

Field Test Research for Subgrade Filling Constructed by Red Sandstone in Liu-Li Expressway

在湖南省高速公路建设中存在大量红砂岩路段,该类岩石因其成因特殊而成分复杂且大部分具有崩解性,作为一种特殊路基填料使用往往导致工程建设成本高,施工进度缓慢,施工质量难以控制。结合湖南长沙浏阳(黄泥界)至醴陵高速公路工程中遇到的红砂岩地质情况,开展红砂岩成分、强度、崩解及其现场试验,试验结果表明,浏醴高速Ⅲ类红砂岩长时间仍会崩解,不能作为一般填石路堤对待;采用预崩解与耙压相结合的工艺适用于该地区红砂岩路基施工;考虑到红砂岩的特殊性,对于全线砂岩挖填接合处、高填方路段等难以压实的地段建议进行强夯加速其沉降。

There are a lot of road sections of red sandstone in expressway construction in Hunan Province.As a kind of special subgrade filler used in construction,those rocks often lead to high costs,slow progress,and the construction quality difficult to control,because of their complex composition and disintegration.In this paper,combined with the geological conditions of red sandstone encountered in Liuyang-Liling expressway in Hunan Province,the composition,strength,disintegration and the field test of red sandstone were carried out.The test results show that red sandstone of Class III can not be treated as a general filler for embankment because it will still disintegrate after a long time.And the construction technology of pre-disintegration combined with rake pressure is suitable for red sandstone roadbed construction in the region.Taken into account the specificity of red sandstone,dynamic compaction is proposed to used in these road sections difficult to compaction,such as excavate-fill junction and high embankment sections,for accelerating their settlement along this full range of road with red sandstone.