盐溶液饱和粘土的直剪试验研究

摘要

在钻孔井壁失稳、核废料处置、库岸滑坡等特殊岩土工程中，孔隙水溶液组分和浓度对土体强度存在重大影响。本文利用直接剪切试验研究了不同浓度盐溶液饱和粘土的强度特性，得出了以下结论：盐溶液饱和粘土能使其固结状态发生改变，随着盐分浓度的增加，土体可以从超固结状态转变为正常固结状态，甚至转变欠固结状态，发生所谓的化学固结；盐溶液浓度的增加可以提高内摩擦角，降低粘聚力，两个强度指标的不同变化控制了土体在不同竖向压力、浓度范围下的强度的不同演变规律。%In some special Geotechnical engineerings, such as the wall stability problem of well, the disposal of nuclear waste, the landslide of reservoir and so on, the species and concentration of porewater have significantly effect on the strength of clay. In this paper, direct shearing tests were preformed to study the strength characteristics of clay samples saturated by salt solution with different concentration. The experimental result shows exposing to salt solution could change the consolidation state of clay sample. With the increasing of salt concentration, clay can be transform from the overconsolidation state into the normal consolidation state, even into the under consolidation state which is likely to induce the chemical consolidation. Increasing of the salt concentration of pore water could rise the frication angle, but depress the cohesion of clay. Therefor, the different variabilities of strength indexs are combined to decide the changing trend of strength of clay saturated by Salt Solution.