路基压实土的超固结应力历史试验研究

Experimental Study on Over-consolidation Stress History of Subgrade Compacted Clay

为研究高填方路堤分层压实过程中的超固结应力历史,对路基回填土分别开展室内击实和一维固结试验。通过采用两种自制击样装置以及标准重型击实钻芯取样等3种方式制备压实土样,研究击实功、击实冲量、含水率以及压实度等多种因素对路堤回填土超固结应力历史的影响。试验结果表明:相同压实度和含水率的压实土对应的应力历史不唯一,压实过程的单位面积击实冲量越大应力历史越大;当击实功和超固结形成路径都相同,压实土在最佳含水率时压实度最高,对应应力历史最大;当含水率相对最佳含水率上下浮动,压实土的应力历史会降低,且含水率越高,压实度对于应力历史的影响幅度越大。

In order to research the over-consolidation stress history of the clay in high-filled embankment during hierarchical compaction process, the indoor compaction and 1D consolidation tests on the embankment backfill clay are preformed. Two kinds of homemade compaction devices and drilling sample from standard heavy compacted clay are chosen to prepare the compacted clay samples. The influences of compaction work, compaction impulse, water content and compaction degree on over-consolidated stress history of embankment backfill clay are researched. The experimental result shows that （1） the compacted clay with the same compaction degree and water content perhaps has different stress historys, and its stress history in compaction process increases as the compaction impulse per unit area increases; （2） when the compaction works and over-consolidated formation paths are the same, the compacted clay has the biggest compaction degree and stress history at the optimal water content; （3） if the water content is in an up or down deviation from the optimal water content, its stress history will be shorter, and the compaction degree affects its stress history more deeply as the water content increases.