Experimental Study on Compressibility and Rebound Characteristics of Sand Reinforced with Polymer and Fiber

ABSTRACT

The compressibility and rebound properties of sand reinforced with polymer and fibers were studied with respect to polymer content, dry density, and types and content of fibers using laboratory standard consolidation experiments. The following conclusions are drawn: (1) with the increase in polymer, the compressive coefficient of reinforced sand decreases gradually. Up to 4%, the compressive coefficient decreases slowly and the resilient rate keeps increasing; (2) with the increase in dry density, the compression coefficient decreases rapidly at first and then changes slowly. Up to 1.55 g/cm³, the compression coefficient changes slowly, while the resilient rate keeps increasing; (3) with the increase in fiber content, the compressive coefficient increases and the compressive characteristics of the sand after adding polypropylene fibers become stronger than those of the sand with addition of sisal fibers. The resilient rate of the reinforced sand keeps increasing and the sand reinforced with sisal fiber has a higher resilient rate; (4) the polymer forms a parallel connection model between sand particles, and the curing film can fill the pore between particles. A spatial stereo structure is formed within the sand mixed with fibers reducing the compression characteristics and increasing the resilience under larger vertical loads.

摘要

通过室内标准固结试验, 从聚合物含量, 干密度, 纤维种类和含量等方面研究了聚合物和纤维加固后砂的压缩和回弹特性。得到以下结论:(1)随着聚合物的增加, 固化砂土的压缩系数逐渐减小。当达到4%, 压缩系数降幅减小而回弹率保持增加。(2)随着干密度的增加, 压缩系数先快速减小后缓慢变化。达到1.55 g/cm³时, 压缩系数变化缓慢, 回弹率持续增加。(3)随着纤维含量的增加, 压缩系数逐渐增大, 且加入聚丙烯纤维后砂土的压缩特性强于加入剑麻纤维后砂土的压缩特性。回弹率同样随着纤维含量的增加而增大, 且加入剑麻纤维的砂土具有更高的回弹率。(4)聚合物在砂粒之间形成平行连接模型, 且固化膜能够填充砂粒之间的孔隙。加入纤维的砂土中形成了一个空间立体结构, 能够在高垂直荷载下降低压缩特性并增强回弹。

KEYWORDS:

• Sand
• polymer
• polypropylene fibers
• sisal fiber
• compression characteristics
• resilient rate

圓键词:

• 砂土
• 聚合物
• 聚丙烯纤维
• 剑麻纤维
• 压缩特性
• 回弹率

Author Contributions

In this study, J.L and C.Q. conceived and designed the experiments; Y.W, Z.C, S.Z, and F.B. performed the experiments; Y.W., J.L., and Y.B. analyzed the data; Y.W. and J.L. wrote the paper; and D.P.K. gave some valuable advices about the structure of the manuscript.

Additional information

Funding

This research was financially supported by Water Conservancy Science and Technology Project of Jiangsu Province, China [grant number 2017010]; Fundamental Research Funds for the Central Universities [Grant No. 2019B77514] and the National Natural Science Foundation of China [grant number 41877212].