Rock and Soil Mechanics ›› 2020, Vol. 41 ›› Issue (8): 2739-2745.doi: 10.16285/j.rsm.2019.6467

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Study on dynamic characteristics of cement-stabilized expansive soil subgrade of heavy-haul railway under immersed environment

SHANG Yong-hui1, 2, XU Lin-rong2, 3, CAI Yu2   

  1. 1. College of Architecture and Civil Engineering, Huanghuai University, Zhumadian, Henan 463000, China 2. School of Civil Engineering, Central South University, Changsha, Hunan 410075, China 3. National Engineering Laboratory for High Speed Railway Construction, Central South University, Changsha, Hunan 410075, China
  • Online:2020-08-09 Published:2021-01-22
  • Contact: XU Lin-rong, male, born in 1964, PhD, Professor, mainly engaged in teaching and research on foundation engineering. E-mail:
  • About author:SHANG Yong-hui, male, born in 1985, PhD, Lecturer, mainly engaged in research on dynamic characteristics of special soil subgrade
  • Supported by:
    the National Natural Science Foundation of China (51078538, 51778634), the Key Projects of Henan Education Department of China (20B580003) and the Key Projects of Science and Technology Department of Henan Province of China (202102310264).

Abstract: The dynamic characteristics of subgrade is aggravated under the interaction of immersed infiltration and dynamic loads of trains, which affects the safety of train operation and long-term stability. Based on the engineering background of cement-stabilized expansive soil subgrade of Hao-Ji heavy-haul railway(Haolebaoji-Ji'an), field excitation tests of subgrade with four million cycles were carried out under dry and immersed conditions to investigate the dynamic characteristics. Large-scale excitation equipment, combined with dead weights, were used to simulate the dynamic behavior of heavy-haul trains with 25-30 t axle load. The test results show that the variations of dynamic stress and acceleration along the depth of subgrade are consistent, and decay rate is 80% at the base of subgrade. The influence of immersed infiltration and dynamic load of train is more significant at the interface of between the subgrade bottom and fill. Under the same loading conditions, the dynamic stress at the interface under the immersed condition is 28% larger than for the dry condition. The acceleration is much less sensitive to the immersed environment than the dynamic stress. At the same time, the dynamic stress level along subgrade depth is much lower than the critical dynamic stress of fill in the same location. The cumulative deformation of subgrade surface under cyclic loading of 4 million times is less than 5 mm and remains stable, which indicates that the improved expansive soil with 3%-5% cement content can be used as the subgrade bottom and fill to meet the dynamic stability requirements of subgrade. The research results can provide theoretical reference for high-quality construction and maintenance of the improved expansive soil subgrade of heavy-haul railway.

Key words: cement-stabilized expansive soil subgrade, dynamic characteristics, excitation test, heavy-haul railway