石灰桩处理岛状冻土地基试验研究

Experimental Study on Treatment of Patchy Permafrost Foundation with Quicklime Piles

针对冻土上限较深的岛状多年冻土地基稳定性问题,本文提出了一种用石灰桩预融处理岛状冻土地基的方法。根据生石灰水化反应放热的特点,提出用石灰桩处理高温岛状冻土地基的桩体材料配合比计算公式,并开展了石灰桩模型试验。结果表明,石灰桩能有效融化多年冻土并对融化后的地基土起到挤密加固作用。保证石灰桩预融效果的3个关键要素是:桩体含水率应控制在15%~19%;从拌和到分层夯填完成时间须控制在5 min以内;生石灰粒径宜控制在6 cm以内。

Aiming at the stability problem of the patchy permafrost foundation with significant upper limit,a new method is put forward by using quicklime pile. Based on the exothermic reaction of quicklime and water,an equation of pile mixture was proposed for the treatment of high-thermal patchy permafrost foundation with quicklime piles. Also, model test for the quicklime pile was conducted. The results show that the permafrost may be melt effectively due to the quicklime piles,and the melt permafrost foundation is compacted and reinforced. The three keys to the effectiveness of the quicklime pile pre-melting are as follows. First,the water content of pile shall be kept 15%~ 19%. Second,the time from mixing to tamping shall be kept within 5 min. Third,the particle diameter of quicklime shall be smaller than 6 cm.