Field investigation and full-scale model testing of mud pumping and its effect on the dynamic properties of the slab track–subgrade interface

Abstract

Passenger comfort and safety are the most important aspects in the operation of high-speed railways. Mud pumping is a typical problem that occurs in the slab track and the subgrade interface, which influences passenger comfort and safety. In this paper, various field investigations and a full-scale model of the slab track and the subgrade are presented. The external and internal characteristics of mud pumping in the slab track–subgrade interface and the influence of mud pumping on the dynamic properties of the slab track–subgrade are analyzed. The results show that mud pumping only occurs at the expansion joints in the concrete base of the slab track structure. This happens due to the infiltration of rainwater into the subgrade bed through the cracks in the expansion joints. When the upper layer of the subgrade is kept saturated in the full-scale model, mud pumping is found to occur after 3.0 × 104 loading cycles. The vibration ratio of the subgrade surface to the concrete base gradually increases with continued cyclic loading. In addition, the cumulative settlement of the subgrade increased continuously. After 2.0 × 106 loading cycles, it was found that a large volume of slurry composed of water and fine particles was squeezed out of the subgrade bed, and mud pumping occurred on the surface of the subgrade bed leading to the formation of a mud layer between the concrete base and the subgrade bed, causing a loss of contact between the subgrade bed and the concrete base. This reduces the ability of the subgrade bed to support the slab track structure.

Experimental Study on Vibration Characteristics of Unit-Plate Ballastless Track Systems Laid on Long-Span Bridges Using Full-Scale Test Rigs

“…These ballastless tracks with different types of isolation layers were arranged into two lines on the composite-girder and the composite-girder had already been built up based on a longspan cable-stayed bridge. In this work, these unit-plate ballastless tracks were fabricated to pave on long-span bridges, and they were arranged with geotextile or rubber isolation layers for further At present, model testing is always used to investigate the dynamic characteristics of railway tracks [17,18] and using a full-scale model can effectively reduce the uncertainties in experimental measurements [19]. In this work, a set of full-scale test rigs were constructed based on two types of ballastless tracks employed in China high-speed railways, which are characterized by their isolation layer types.…”

“…Besides this, the introduction of an elastic isolation layer can separate the self-compacting concrete and basement as well as effectively absorb the vibrations in comparison with the conventional ballastless track systems [16]. At present, model testing is always used to investigate the dynamic characteristics of railway tracks [17,18] and using a full-scale model can effectively reduce the uncertainties in experimental measurements [19]. In this work, a set of full-scale test rigs were constructed based on two types of ballastless tracks employed in China high-speed railways, which are characterized by their isolation layer types.…”

Saturated Ground Vibration Analysis Based on a Three-Dimensional Coupled Train-Track-Soil Interaction Model

“…A dynamic load with an amplitude of 96 kN and a frequency of 5 Hz, is applied to the bearing plate. The details of this lab-test can be found from [44][45][46][47]. The lab-test model and numerical model are shown in Figure 4.…”

Behavior and Control of the Ballastless Track‐Subgrade Vibration Induced by High‐Speed Trains Moving on the Subgrade Bed with Mud Pumping

“…e major characteristic of mud pumping in the ballastless track-subgrade is that a large number of fine particles are squeezed out of the subgrade bed. Mud pumping only occurs in the expansion joints of the concrete base of the ballastless track structure during the rainy season [42]. e authors established a full-scale model of the ballastless track-subgrade to analyze the vibration behavior of the model under normal and pumping conditions and after mud pumping reinforcement under cyclic dynamic loading and the reinforcement effect of mud pumping by using the LVER.…”