聚丙烯纤维加筋二灰土动强度试验研究

第38卷第2期 娃酸盐通报Vol.38 No.2 2019 年 2 月_______________BULLETIN OF THE CHINESE CERAMIC SOCIETY___________________February,2019

聚丙烯纤维加筋二灰土动强度试验研究

张向东\蔡冀奇\杨兴宇2，殷凡3，唐楠楠1

(1.辽宁工程技术大学土木工程学院，阜新123009;2.中铁七局集团第三工程有限公司，西安710024;

3.中铁十二局集团第四工程有限公司，西安710016)

摘要:为研究纤维掺量对加筋二灰土动强度特性影响，将长度为12 mm的聚丙烯纤维按照0.12%、0.24%和0.36%的质量比掺入二灰土中。利用GDS三轴试验系统进行不同围压和动应力幅值条件下纤维加筋二灰土的动三轴试验。

试验结果表明：随着聚丙烯纤维掺量的增加，二灰土动黏聚力先增大后减小，当纤维掺量达到〇.32%时，动黏聚力 出现峰值，此时为最佳纤维掺量;而纤维加筋二灰土动内摩擦角与纤维掺量呈现正相关的关系。此外，纤维在土中 形成三维网络框架，使土体嵌锁愈加紧密，并通过拉筋作用，减缓或阻止裂纹扩展，最终使土体破坏形式由具有明 显贯通裂隙的脆性破坏逐渐转变为侧向鼓胀变形破坏。

关键词:聚丙烯纤维；纤维掺量；二灰土；动强度

中图分类号:U414 文献标识码:A文章编号:1001-1625 (2019)02-0568-06

Experimental Study on the Dynamic Strength of Polypropylene

Fiber Reinforced Lime-Fly Ash

ZHANG Xiang-dong1, CAI Ji-qi1, YANG Xing-yu, YIN Fan3, TANG Nan-nan1

(1. School of Civil Engineering, Liaoning Technical University ,Fuxin 123000, China ；2. The 3th Engineering Co. ,Ltd. , China Railway 7th

Bureau Group,Xian 710024,China；3. The 4th Engineering Co. Ltd. ,China Railway 12th Bureau Group,Xian 710016 ,China)

A b stract：In order to investigate the effect of different fiber content on the dynamic strength of the

reinforced lime-fly ash soil (L F S) , polypropylene fiber with length of 12 mm was added into the LFS in different weight proportions of 0. 12% , 0. 24% and 0. 36% , respectively. The GDS Triaxial Testing System ( GDSTTS) was employed to perform dynamic triaxial tests on fiber-reinforced LFS under different confining pressures and stress amplitudes. The experiment results show that with more polypropylene fiber added, dynamic cohesive force of the LFS is first increased and then decreased. When the fiber content is

0. 32% , the dynamic cohesive force reaches the peak, indicating that 0. 32% is the optimal fiber

content. Besides, a positive correlation between the dynamic internal friction angle and fiber content is also observed. In addition, the fiber forms three-dimensional network in LF S, making the LFS more tightly integrated. Moreover, the fiber retards or prevents the expansion of cracks through reinforcement effects, which gradually transforms the collapse mode of the fiber-reinforced LFS from brittle failure with obvious transfixion cracks into lateral bulging deformation failure.

Key words：polypropylene fiber；fiber content；lime-fly ash soil (L F S) ；dynamic strength

1引言

在众多土工复合材料中，纤维加筋土具有力学性好、水力学性稳定和不易形成软弱结构面等优点，已广 泛应用于挡土墙、道路和护坡等工程中[1]。近几年来，国内地震频发，对纤维加筋土工程的安全提出严峻挑 战。因此，必须在设计中充分考虑地震动荷载对纤维加筋土强度的影响。国内外学者对纤维加筋土的静力 特性已开展大量的试验研究，高磊等[2]通过对玄武岩纤维加筋黏土进行直剪试验，并借助S E M扫描电镜从

基金项目：国家自然科学基金(51774166)

作者简介:张向东（1962-)，男，博士，教授.主要从事土木工程方面的研究.

通讯作者:蔡冀奇，硕士研究生.