干湿循环下含盐量变化对遗址土剪切强度影响的试验研究  

Testing Study on Influence of Salt Contents on Shear Strength of Ancient Relics Soil at Dry-wet Cycle

作　　者：沈云霞[1,2] 谌文武[1,2] 杜伟飞[1,2] 匡静[1,2] 

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000 [2]兰州大学土木工程与力学学院,甘肃兰州730000

出　　处：《西北地震学报》2011年第B08期227-230,共4页Northwestern Seismological Journal

基　　金：国家科技部"十一五"支撑计划(2010BAK67B16;2006BAK30B02);教育部西部灾害与环境力学重点实验室开放基金(klmwde201006)

摘　　要：中国西北干旱和半干旱地区集中降雨和强烈蒸发的特殊气候环境加剧了对土遗址的破坏。以掺入不同含量Na2SO4和NaCl的重塑土样为研究对象,通过室内模拟开放系统下干湿循环过程,并采用声波测试,反映含盐类遗址土在干湿循环下的劣化过程;测试多次循环后的遗址土剪切强度随含盐量的变化规律,并从盐类性质及波速两方面分析了干湿循环对遗址土剪切强度的作用机理。结果表明:在含水率一定的情况下纵波波速随干湿循环次数的增加而减小;干湿循环后的土体黏聚力随着盐分含量的增加呈下降趋势,内摩擦角则出现先增大后减小的现象;纵波波速与黏聚力随着含盐量的增长整体变化趋势有较好的相关性,与内摩擦角的相关性则表现为纵波波速的间断性和内摩擦角阶段性的契合。The damage of soil ancient relics could be exacerbated by the climate of strong evaporation and concentrated rainfall in dry and semi-arid area in northwest China.In this paper,taking the rebuilding soil samples which mixed different Na2SO4 and NaCl contents as the research object,through indoor simulation of dry-wet cycle environment and the acoustic test,the deterioration process of the ancient relics soil with salts is studied.The variation of shear strength of longitudinal wave with change of salts content in the relics soil under several the dry-wet cycle is tested,and the mechanism of the shear strength change in the relics soil is analyzed from two respects：the salt properties and wave velocity.The result shows that the velocity of longitudinal wave decreases as the cycles of dry-wet cycle increases with certain moisture content,the cohesion of soil declines with addition of salts content while the internal friction angle accretes first and then decreases.A good coherent relationship between the change of the velocity and the cohesion in the process of salts content increasing is obtained.The correlation between the velocity and internal friction angle shows the fitting of discontinuity of the velocity with the turning points of internal friction angle.

关 键 词：遗迹土 易溶盐 干湿循环 纵波波速 剪切强度 

分 类 号：TU411[建筑科学—岩土工程]