Mud pumping in high-speed railway: in-situ soil core test and full-scale model testing

Abstract

Mud pumping induced by moving train loads on rainwater-intruded roadbed causes intensive track vibrations and threatens safety of high-speed trains. In this paper, a vehicle–track–subgrade finite element model was established to analyze the dynamic responses of a ballastless track, and results showed that the concrete base and roadbed were detached because of the whipping effect arising from the rainwater intrusion channel. An in-situ soil core test showed that the intruded rainwater accumulated in roadbed to form standing water and saturated the roadbed. The flapping action of the concrete base caused by the whipping effect led to mud formation mixed with fine particles and rainwater, which migrated upward under the pore-water pressure (PWP) gradient. Mud pumping resulted from continuous particle migration in the saturated roadbed under moving train loads: under normal roadbed condition, coarse and fine particles were uniformly distributed in the roadbed; in early period of mud pumping, fine particles migrated downward to bottom of the roadbed because of the rainwater infiltration flow; in middle stage of mud pumping, fine particles migrated upward and gathered at the roadbed surface under PWP gradient; in later period of mud pumping, fine particles were entrained and removed with the dissipation of excess PWP. Moreover, a full-scale physical model was established to reproduce mud pumping, and polyurethane injection remediation against mud pumping was validated on this physical model. The remediation method was applied to an in-situ mud pumping. The deviation of the vertical track profile reduced remarkably and remained at a low level within half a year, showing a good long-term service performance of the polyurethane remediated roadbed.

Multi-defect risk assessment in high-speed rail subgrade infrastructure in China

“…Number of days with maximum temperature exceeding 35 degrees celsius : This data can serve as an indicator reflecting extreme high temperatures 16 .…”

“…The findings revealed that the frost heave rate was influenced by the initial water content before freezing and the replenishment of moisture during the freezing process. Wan et al (2022) established a vehicle-track-subgrade vertical dynamic coupled analysis model was established using ABAQUS 16 . The study found that debonding easily occurred between the end of the base plate and the surface of the subgrade.…”

Feature analysis of precipitation-induced subgrade defects on a high-speed rail ballasted track using multiple track inspection data: A case study

“…4 Typical water-induced subgrade defects, including mud pumping and differential settlement, may occur. 5,6 These defects can weaken the support ability of the subgrade to slab track, causing the deterioration of the track geometry and thus bringing a potential threat to the operation safety of HSR trains. 7 When the track undergoes such problems, the HSR trains may need to reduce the operation speed, which leads to a decrease in the operation efficiency.…”