降雨对膨胀土路堤填筑质量的影响及其对策

降雨对膨胀土路堤填筑质量的影响及其对策具有工程应用价值。对降雨引起的膨胀土路堤含水量和压实度变化进行了试验研究,试验表明:短历时、弱降雨对路基膨胀土路基的含水量和压实度影响甚微;长历时、强降雨对路基膨胀土路基的的影响深度约为30cm,影响深度范围内含水量上升了1%~5%,素土的压实度下降约15%,灰土的压实度基本保持不变。为将降雨对路基的不利影响降低到最小,一般可在降雨发生前,采用素土碾压覆盖已填筑好的路基。对受降雨影响的碾压土层可进行掺灰处理。

The Effect of Rainfall on Constructing Quality of Expansive Soil Subgrade and Its Countermeasures

The subgrade of expansive soil is sensitive to climate changing and the influence of rainfall and sunshine is peculiarly obvious during construction phase. As a result the studying on the effect of constructing quality impacted by rainfall and its countermeasure is significance. Testing on the variation of water content and degree of compaction for expansive soil subgrade caused by rainfall are carried out. The testing results indicate that it is little influenced by rainfall with a short duration and weak intensity, while a influenced depth approximately 30 cm, when suffered from rainfall with a long duration and strong intensity. In the range of this depth, water content of raw soils ascends 1%~5%, in the meanwhile the degree of compaction descends about 15% for raw soil and keeps nearly unchanged for lime-treated soil. Based on above, a general method suggested is to cover the compacted subgrade using raw soil so as to reduce the adverse effect of rainfall on subgrade to a minimum level. The compacted soil layer subjected to rainfall should be dealt with lime.