干湿交替作用对关中地区塿土临界剪切力的影响  

Effect of dry-wet alternation on critical shear stress of Lou Soil in the Guanzhong area

作　　者：宋鹏帅 王健[2] 陈琳 曹博召 SONG Pengshuai;WANG Jian;CHEN Lin;CAO Bozhao(Institute of Soil and Water Conservation,Northwest A&F University,Yangling 712100,Shaanxi,China;College of Natural Resources and Environment,Northwest A&F University,Yangling 712100,Shaanxi,China)

机构地区：[1]西北农林科技大学水土保持研究所,陕西杨凌712100 [2]西北农林科技大学资源环境学院,陕西杨凌712100

出　　处：《干旱区研究》2021年第6期1731-1740,共10页Arid Zone Research

基　　金：“秦巴山地”近自然坡面整治水土保持关键技术示范与推广项目;国家自然科学基金(41771308)。

摘　　要：为了探究山地丘陵区梯田田坎在自然营力作用下的抵抗剪切破坏机理,通过室内试验测定土壤的临界剪切力,分析干湿交替作用对土壤临界剪切力的影响,以及确定不同干湿交替处理后土壤临界剪切力与土壤黏聚力之间的关系。结果表明:(1)在1~7次干湿交替过程中,土壤单位高度土体水头差与渗流流速之间呈正相关关系,并随着干湿交替次数的增加土壤渗透系数逐渐增大,然后趋于稳定。(2)随着干湿交替次数的增加,1~3次干湿交替对土壤临界剪切力无显著影响,4~7次干湿交替后临界剪切力呈小幅增加并趋于稳定。检验分析表明,不同干湿交替水平对土壤临界剪切力有一定程度的影响,且二者存在正相关关系。(3)随着土壤临界剪切力的增加,土壤黏聚力也逐渐增大,且二者具有显著相关性。研究结果可为梯田修筑及相关工程实践提供理论依据和技术支撑。We explored shear failure resistance mechanisms of terraced fields in mountainous and hilly areas under natural forces.We measured critical shear force of soil using laboratory tests,analyzed the effect of dry-wet alternations on critical shear force of soil,and determined the relationship between critical shear force of soil and soil cohesion following different dry-wet alternation treatments.The results showed(1)during 1-7 dry-wet alternations,the water head difference per unit soil mass was positively correlated with seepage velocity and the soil permeability coefficient increased exponentially with increasing number of dry-wet alternations.(2)With the increasing number of dry-wet alternations,the critical shear force was not significantly affected by 1-3 dry-wet alternations,but increased slightly and stabilized after 4-7 dry-wet alternations.The results show that different dry-wet alternation levels can significantly affect critical shear soil stress and highlights a positive correlation.(3)With increasing critical shear stress,soil cohesion gradually increased,which was significantly correlated.This experiment includes compaction test,dry-wet alternation test and critical shear test.Firstly,the experimental soil was compacted,and then the soil that reached the volume mass set in the experiment was treated with different times(0-7 times)of dry-wet alternation.The critical shear force experiment was carried out for the soil treated with different dry-wet alternation times.The soil head difference per unit height,the permeability coefficient and the critical shear force of the soil were measured,and the relationship between the critical shear force and the soil cohesion was analyzed.The results of this study provide theoretical support for relevant experimental research and engineering practices of terraced fields.

关 键 词：干湿交替 土壤临界剪切力 黏聚力 土壤渗透系数 

分 类 号：S157.1[农业科学—土壤学]