斥水剂作用下掺砂心墙料恒压渗透试验研究

Constant Pressure Permeability Tests of Core Wall Mixed Sand Under the Effect of Water-Repellent Powders

为获得斥水剂作用下掺砂心墙料的渗透性能,采用自制恒压渗透仪,开展了不同土石比、击实数和水头条件下的恒压渗透试验,获得了掺砂斥水心墙料起渗历时、穿透水头和稳定渗透系数的变化规律.结果表明:起渗历时随着土石比的减小和击实数的增加而增加,随着水头的增加而减小.对于未掺砂的斥水心墙料,水头小于5 m时,水分能长时间停留在试样表层.对于掺砂斥水心墙料,穿透水头随着土石比的增大而减小,受击实数影响不明显.击实数相同时,稳定渗透系数与土石比呈较好的正相关线性关系;土石比相同时,稳定渗透系数与击实数呈较好的负相关线性关系.水头越大,掺砂斥水心墙料的稳定渗透系数有所增大,总体上影响不大.与传统掺砂心墙料防渗效果相比,掺砂斥水心墙料抗渗性能提升较明显,可为心墙设计提供新的思路.

In order to obtain the permeability of core wall mixed sand under the effect of water-repellent powders,the constant pressure permeability tests of a water-repellent core wall under different soil-rock ratios,compaction times,and water head were carried out by using a self-made constant pressure permeability instrument.The variation of the initial penetration time,penetration water head,and stable permeability were obtained.It is shown that the initial penetration time increases with the decrease of soilrock ratio and increase of compaction numbers,while it decreases with the increase of water head.When the water head is less than 5m,water can rarely infiltrate into the water-repellent core material without sand.The penetration head decreases with the increase of soil-rock ratio but has no effect by compaction number.At the same compaction numbers,the stable permeability coefficient has a good positive correlation and linear relationship with the soil-rock ratio,while at the same soil-rock ratio,the stable permeability coefficient has a good negative correlation and linear relationship with the compaction times.The stable permeability coefficient increases with the increase of water head not obviously.Compared with the traditional core wall mixed sand,the impermeability of water-repellent core wall mixed sand is obviously improved,which can provide a reference for the design of the core wall.