含水量的变化对非饱和黄土强度的影响  

Effect of the change in water content on the strength of unsaturated loess

作　　者：王吉庆 程双[1] 雷胜友 李志远[2] 刘昭[2] WANG Jiqing;CHENG Shuang;LEI Shengyou;LI Zhiyuan;LIU Zhao(Jiangxi Provincial Expressway Investment Group Co.,Ltd.Ganzhou Management Center,Ganzhou Jiangxi 341000;Highway College,Chang＇an University,Xi＇an Shanxi 710064)

机构地区：[1]江西省高速集团赣州管理中心,江西赣州341000 [2]长安大学公路学院,陕西西安710061

出　　处：《江西公路科技》2018年第3期73-78,共6页

摘　　要：将非饱和土基质吸力对土体强度的贡献等效成小主应力增量，即三轴试验中的附加围压．通过对土体极限应力莫尔圆的几何图形分析，求得小主应力增量，并认为土体在破坏时还是处于极限状态．提出了粘聚力和内摩擦角同时变化时的土体强度计算方法，得到了强度参数随含水量变化的函数关系式．研究了非饱和黄土破坏时大主应力随含水量变化的关系曲线，发现计算曲线与实验曲线的规律性相同，随着含水量的增加，大主应力计算值和实测值的差异越来越小，其相对误差最大值为11．63％，最小值为1．59％，从而说明该计算方法是可靠的；随含水量的增大，当粘聚力和内摩擦角同时变化时，计算所得的大主应力值较小，当仅有内摩擦角变化，计算所得的大主应力值大．两者相差1．26-2．17倍，从而说明含水量的变化对非饱和土的强度有显著影响。The suction＇s contribution to the strength of soil can be regarded as the minor principal stress increase, that is all round pressure increase in triaxial test. Using Mohr＇s circle,we can get minor principal stress increase, and then got a function of major principal stress while both changing of cohesion and angle of internal friction, as well as the relationship between strength index change and water content, obtained major principal stress for unsaturated loess for different water content, and found that major principal stress decreases with the increase of water content, which above are consistent with the experimental results, and maximum relative error is ll.63%,minimum one is 1.59%.With the change of water content,when cohesion and angle of internal friction both change, the value of major principal stress calculated is more than that only when cohesion changes,the relative error interval is 1.26 to 2.17. The method in which major principal stress is calculated for different water content is more sim- ple and exact,can be used to predict the strength of unsaturated soil .

关 键 词：路基工程 非饱和黄土 含水量 强度增量 等效围压 三轴试验 

分 类 号：TU43[建筑科学—岩土工程]