摘要
为了研究掺砂量和阴性聚丙烯酰胺（PAM）对纤维水泥土强度的影响规律和作用机制，分别配制掺4％，8％，12％，16％和20％素土重的砂和2％，6％，10％水泥重的PAM纯水泥土、聚丙烯纤维水泥土、剑麻纤维水泥土及二者混杂纤维水泥土试样共96组，进行无侧限抗压强度试验。运用扫描电镜（SEM）研究聚丙烯纤维和剑麻纤维在土样中的形态特征。结果表明：这2种纤维的掺入均能大幅度提高水泥土的无侧限抗压强度，提高幅度为40．5％～54．1％，掺砂量和PAM掺量对纤维水泥土的强度有明显的影响，随掺砂量和PAM掺量的增加，纤维水泥土的无侧限抗压强度先增大后减少；在掺砂量为12％和PAM掺量为6％时，纤维的加筋作用达到最优，此时无侧限抗压强度最大；此外，水泥水化物及较硬砂颗粒与PAM的水解产物结合，使得纤维表面变粗糙，从而增加了界面的黏结特性；聚丙烯纤维与剑麻纤维的混杂在一定程度上增大了水泥土的无侧限抗压强度，表现出了一定的混杂效应，PAM和砂的掺加对混杂系数有较大影响。
In order to study the influence and mechanism of sand content and negative polyacrylamide （PAM） on the strength of polypropylene fiber, sisal fiber as well as the hybrid fiber reinforced cement soils, sand and PAM were included in polypropylene fiber, sisal fiber as well as the hybrid fiber reinforced cement soil at 4%, 8%, 12%, 16% and 20% by weight of raw soil and 2%, 6%, 10% by weight of ce- ment respectively, ninety-six groups of samples were prepared and subjected to unconfined compression test. The evolution of the surface morphological structure of sisal fiber and polypropylene fiber in cement soil matrix was characterized by using scanning electron microscopy （SEM）. The results show that the in- clusion of two kinds of fiber has greatly improved the unconfined compressive strength of cement soil, the increased strength ranges from 40. 5% to 54. 1%. Sands content and PAM content have significant influ- ence on the strength of cement soil, the unconfined compressive strength of fiber reinforced cement soil in- creases first and then decreases with the increase of sand content and PAM content, the maximum value of unconfined compressive strength is observed at the optimum sand content of 12% and the optimum PAM content of 6%. Besides, the hydration of cement and hard sand particles combined with hydrolysis product ＂ of PAM make the surface of fiber become rough, thereby improves the bonding properties of the interface between fiber and cemented soil matrix. The mix of sisal fiber and polypropylene fiber increases the uncon- fined compressive strength of cemented soil in a certain extent and the confounding effect is found in hybrid fiber cemented soil. The inclusion of PAM and sand has significant effect on hybrid coefficient.
出处
《中国铁道科学》
EI
CAS
CSCD
北大核心
2014年第6期7-14,共8页
China Railway Science
基金
国家"九七三"计划项目(2015CB0578000)
中央高校基本科研业务费专项资金资助项目(2012YJS086)
关键词
软土地基
改性
水泥土
砂
聚丙烯酰胺
纤维
混杂
无侧限抗压强度
Soft soil foundation
Modification
Cement soil
Sand
Polyacrylamide
Fiber
Hybrid
Un-confined compressive strength
