注水方式对膨胀土膨胀量的影响研究

为了研究不同注水方式对膨胀土膨胀量的影响,取某高速铁路地基膨胀泥岩,进行不同数量开孔和不开孔方式注水的重塑膨胀土浸水膨胀变形试验,并分析得到了开孔造成的土体损失体积率与膨胀量损失量之间的关系。试验结果表明:开孔注水与不开孔注水的膨胀时程曲线、膨胀量与含水率关系曲线有很大不同;各注水方式下,膨胀时程曲线和膨胀量与含水率关系曲线变化规律基本一致。开孔注水方式下,膨胀时程曲线、膨胀量与含水率关系曲线可分为三个阶段:初始快速膨胀阶段、减速膨胀及逐渐稳定阶段、突然增长阶段。不开孔注水方式下,膨胀时程曲线、膨胀量与含水率关系曲线可分为四个阶段:初始缓慢膨胀阶段、快速膨胀阶段、减速膨胀及逐渐稳定阶段、突然增长阶段。土体损失体积率与膨胀量损失量之间呈良好的线性关系,其关系式为Δδ=0.617ΔV+0.02。

Influence of water injection mode on swelling amount of expansive soil

In order to study the influences from different water injection modes on the swelling amount of expansive soil，the moistening-swelling deformation experiments on the remolded expansive soil samples under the modes of both the water injection with different numbers of holes and the water injection without hole are carried out by taking the expansive mudstone from the foundation of a high-speed railway，from which the relationship between the volume loss rate and the amount of expansion loss of the soil mass caused by the hole-opening is analyzed as well. The experiment result shows that the relationship curve among the time-travel expansive curve，swelling amount and water content under the mode of water injection with hole is quite different from that under the mode of water injection without hole，while the changing laws of the relationship curves among the time-travel expansive curve，swelling amount and water content under both the modes of water injection are basically coincided. Under the mode of water injection with hole，the relationship curve among the time-travel expansive curve，swelling amount and water content can be divided into three phases，i. e. initial quick swelling phase，decelerated swelling and gradually stable phase and sudden swelling phase. Under the mode of water injection without hole，the relationship curve among the time-travel expansive curve，swelling amount and water content can be divided into four phases，i. e. initial slow swelling phase，quick swelling phase， decelerated swelling and gradually stable phase and sudden increasing phase. Meanwhile，a better linear relationship presents between both the volume loss rate and the amount of expansion loss of the soil mass，for which the relationalexpression is Δδ = 0. 617ΔV + 0. 02.