以强度增长率评价麦秸秆加筋盐渍土的加筋效果  

Examination of reinforcement effect on basis of strength increment of reinforced saline soil with wheat straw and lime

作　　者：李敏[1] 柴寿喜[2] 王晓燕[3] 魏丽[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,兰州730000 [2]天津城市建设学院天津市软土特性与工程环境重点实验室,天津300384 [3]中水北方勘测设计研究有限责任公司,天津300222

出　　处：《岩土力学》2011年第4期1051-1056,共6页Rock and Soil Mechanics

基　　金：天津市自然科学基金(No.07JCYBJC12900);国家自然科学基金(No.40772166)

摘　　要：采用麦秸秆与石灰共同加筋固化滨海盐渍土,可解决由于盐胀、溶陷和吸湿软化引起的土体强度下降问题。首先,制备盐渍土、石灰土、麦秸秆加筋盐渍土和麦秸秆加筋石灰土试样(整体均匀加筋、上部均匀加筋和下部均匀加筋);进而,进行φ50 mm试样、φ152 mm重型击实试样和φ102 mm轻型击实试样的无侧限抗压强度试验,以及φ61.8 mm试样三轴压缩试验;最后,分析抗压强度增长率、主应力差比值和黏聚力增长率的变化规律,以评价麦秸秆的加筋效果。结果表明:①麦秸秆加筋增强了土的抗压强度和抗变形能力。②麦秸秆加筋提高了土的黏聚力,在试样下部加筋,加筋效果更好。③加筋石灰土的强度由麦秸秆和石灰共同承担,加筋石灰土的浸水稳定性来源于石灰的固化作用。④低围压时,加筋对土的侧向变形约束较强;高围压时,加筋和围压共同限制土的侧向变形。采用麦秸秆加筋是滨海盐渍土的一种有效处理方法。Inferior strength, which is caused by salt expansion, dissolution and water absorption of inshore saline soil, will be prevented with the help of reinforcement with wheat straw and lime. First, some samples are prepared, which including saline soil, reinforced saline soil with wheat straw, lime-saline soil, and reinforced saline soil with lime and wheat straw as the way of reinforcement in whole, upper and lower position respectively. Then, unconfined compressive strength tests of 50 mm, 152 mm （heavy compaction specimen） and 102 mm （lightly compaction specimen）, as well as triaxial shear test of 61.8 mm in diameter are carried out. Finally, strength increment, ratio of deviator stress, and cohesion increment are defined to evaluate the reinforcement effect. The results show that： 1. Reinforcement raise the strength and the anti-deformation of soil. 2. Reinforced action increase largely the cohesion of soil, and the reinforcement in lower position can contribute a more effective role. 3. Strength of reinforced soil is contributed mostly by wheat straw and lime; the strength in water depends on chemical reaction of lime. 4. Lateral deformation of reinforced soil is restricted by means of wheat straw within a lower confining pressure, and that is supported jointly by reinforcement and confining pressure within a higher confining pressure. Reinforcement with wheat straw is one of the suitable means for improving strength and anti-deformation of inshore saline soil.

关 键 词：加筋土 抗压强度 抗剪强度 强度增长 应力-应变 麦秸秆 滨海盐渍土 

分 类 号：TU443[建筑科学—岩土工程]