GUO Q M, YANG L, ZHAO H, et al．Research on the strength characteristics and engineering application of composite feldspar powder subgrade[J]. Journal of Henan Polytechnic University( Natural Science) ， doi: 10.16186/j.cnki.1673-9787.2026030011.

doi: 10.16186/j.cnki.1673-9787.2026030011.

Received： 2026-03-11

Revised： 2026-05-06

Online： 2026-08-18

Research on the strength characteristics and engineering application of composite feldspar powder subgrade (Online)

GUO Qiaoming1, YANG Lu1, ZHAO Hua2, WU Qilin3, LI Chunzhi2, QI Huaan3, GUAN Bowen3

1.Jiangxi Provincial Communications Investment Group Co., Ltd., Nanchang 330199, Jiangxi,China；2.School of Infrastructure Engineering, Nanchang University, Nanchang University, Nanchang 330131, Jiangxi, China；3.School of Material Science and Engineering, Chang’an University, Xi’an 710064, Shaanxi,China

Abstract: Objectives In order to solve the problem that the by-product feldspar powder produced after lithium extraction from lithium-containing porcelain clay ore is difficult to be consumed on a large scale, which restricts the development of lithium battery industry and the shortage of roadbed fillers along the line, this article focuses on Jiangxi red low liquid limit clay widely distributed along the reconstruction and expansion project of Changfu-Jinyushi section and feldspar powder produced in the process of lithium extraction as the research object, and prepares a new type of composite feldspar powder roadbed filler. Methods Firstly, the preliminary mix ratio design of the new subgrade filler was completed, and the compaction test was carried out on the samples of each mix ratio to determine the optimal moisture content and maximum dry density. Then the CBR test was carried out to analyze the strength characteristics of each mix ratio filler. According to the indoor test results, the field test of composite feldspar powder roadbed filler was carried out for the reconstruction and expansion of Changjin Xiapu Interchange Connection Line Section, and the appropriate roadbed construction parameters and construction technology were determined, and the quality inspection was carried out. Results The results show that feldspar powder can increase the maximum dry density of red low liquid limit clay and promote the close arrangement of particles. However, excessive feldspar powder particles may lead to deterioration of gradation, destroy the particle arrangement system, and reduce the density. When the mixture ratio of roadbed filler is feldspar powder : red low liquid limit clay = 4:6, it has a reasonable particle structure, achieves the best dense state, and has the largest CBR value and high strength. Combined with PCAS software, the surface of subgrade is analyzed. When the mixing times of composite feldspar powder subgrade section is 4, the uniformity of subgrade filling is the highest, and the compaction degree test results meet the design requirements. The application effect is good and meets the requirements of first-class highway subgrade filling. Conclusion Combined with the application of composite feldspar powder in the actual project of the test road, the layered paving, mixing and rolling process of the composite feldspar powder roadbed filler is proposed to realize the application of feldspar powder in the roadbed project.

Key words: subgrade engineering; lithium slag; feldspar powder; subgrade fill material; subgrade construction