# Experimental Study on Strength of Polypropylene Fiber Reinforced Cemented Silt Soil
## 5 Conclusions  
1. Through range analysis, the UCS influencing factors of fiber cement soil from high to low were: cement dosage, fiber content, and fiber length; through the orthogonal test, the ratio of the maximum UCS of fiber cement soil was obtained as follows: the cement dosage was 18%, the fiber content was 0.4%, and the fiber length was 3 mm. The UCS could reach 1.63 MPa, which was 4.8 times that of the sample without fiber and the cement dosage was 9%.
2. When the cement dosage was 15%, the failure mode of cement solidified soil without fiber was brittle failure, and when cement dosage was 15%, fiber length was 9 mm, the failure mode of cement solidified soil with fiber was plastic failure.
3. The UU test showed that when the cement dosage was 15% and the fiber length was 9 mm, with the increase in the fiber content, not only the peak stress and failure strain of fiber-cured soil were improved, but also the cohesion and internal friction angle were gradually increased.
4. The stress-strain curves of fiber cement soil and concrete under uniaxial compression were similar, and the equation was established and fitted by using the relative stress-relative strain relationship. The fiber cement soil under confining pressure was established by hyperbolic function and was fitted by Kondner hyperbolic curve.
5. The failure mode of fiber cement soil showed that when the cement dosage was 15% and the fiber length was 9 mm, with the increase in the fiber content, the cracks in the failure of cement soil were gradually reduced, indicating that fiber can effectively improve the strength and deformation of cement soil.  
Figure 11: SEM chart of fiber cement soil. (**a**) fiber content 0%; (**b**) fiber content 0.1%; (**c**) fiber content 0.2%; (**d**) fiber content 0.4%.  
In this paper, the strength and deformation characteristics of fiber cement soil were studied through the UCS test and UU test. However, there was no research on subsequent tests of fiber cement soil, such as water stability and dry wet cycle test, and there was also a lack of research on tensile property test of fiber cement soil. In addition, we can apply dynamic load to the sample through the true triaxial test, simulate the load action of fiber cement soil in the process of vehicle operation, and study the applicability of fiber cement soil in subgrade reinforcement.  
Conceptualization, S.L. and S.Z.; methodology, Z.H. and D.F.; validation, X.Y.; formal analysis, Y.X.; investigation, Y.X.; data curation, X.Y. and D.F.; writing--original draft preparation, X.Y.; writing--review and editing, S.L. and Z.H.; supervision, S.Z.; project administration, S.L. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China, grant number No. 52078142, Natural Science Foundation of Guangdong Province, grant number No. 2022A1515011047, Science and Technology Program of Guangzhou, China, grant number No. 202002030194.  
Not applicable.  
The data used to support the findings of this study are included in the article.  
The authors declare no conflict of interest.