Hongsheng Qiu

Bio: Hongsheng Qiu is an academic researcher from Wuhan University of Technology. The author has contributed to research in topics: Ballast & Track (rail transport). The author has an hindex of 4, co-authored 7 publications receiving 75 citations.

Prediction of Ground Settlement Induced by Slurry Shield Tunnelling in Granular Soils

Abstract: Underground structures play an important role in achieving the requirements of rapid urban development such as tunnels, parking garages, facilities, etc. To achieve what is needed, new transportation methods have been proposed to solve traffic congestion problems by using of high-speed railway and subway tunnels. One of the issues in urban spaces due to tunnel excavation is considerable surface settlements that also induce problems for surface structures. There are a variety of published relationships concerned with field measurements and theoretical approaches to evaluating the amount of the maximum surface settlement value due to tunneling. This paper studies the ground surface settlement caused by the Greater Cairo Metro – Line 3 - Phase-1. This project was constructed by a slurry shield Tunnel Boring Machine (TBM). Therefore, this work consists of two parts. The first part presents the details of the project and monitoring results field and laboratory geotechnical investigations in order to determine the soil properties. The second part is to the comparison between the field measurements and theoretical approaches for surface settlement due to tunneling construction. At the end of the works, the results show that the more convenient methods which approach the field measurements, and the major transverse settlement occurs within the area about 2.6 times the diameter of the tunnel excavation. Doi: 10.28991/cej-2020-03091617 Full Text: PDF

Influence of Cairo Metro Tunnel Excavation on Pile Deep Foundation of the Adjacent Underground Structures: Numerical Study

Abstract: Day by day the call to solve traffic congestion problems is increasing. Subway tunnels and high-speed railway are commonly used for transportation. Therefore, tunnel construction induces soil movement, which in turn affects the stability and integrity of adjacent existing buildings. A series of numerical simulations have been established to investigate the effects of tunnel construction of the Greater Cairo Metro–Line 3-Phase-1 on adjacent pile cap foundations of Garage El-Attaba building. Many parameters have been investigated such as tunnel diameter and the distance between pile and tunnel at different tunnel axis and deep and shallow tunnel. After thorough analysis of the results’ simulation, it was found that the tunneling induces additional axial forces and bending moment as well as increasing axial settlement and lateral deflection. Moreover, the results obtained from the parametric study for the shallow and deep tunnel show that the tunnel depth has a much significant effect on piles responses. Finally, the tunnel diameter has an impact on pile responses as well as the pile cap foundation influenced by the tunnel when the tunnel is in very close vicinity of the pile, and its effect is modest to negligible if located far away from the buildings.

Discrete element modeling of a cross-river tunnel under subway train operation during peak and off-peak periods

Abstract: In China, a large number of passengers during peak period are a key problem issue that results in a peak load on the subway tunnel The irregular vibration due to the overloading of train will cause critical damage to rail track and foundations Due to the lack of field monitoring data, the effects of trainload-induced irregular vibration to the stability of concrete foundation and surrounding area remain a crucial scientific challenge In current study, a cross-river tunnel in Wuhan subway 2nd line was selected as a case study The numerical model was developed by using the discrete element method with the consideration of rail track, sleeper, concrete lining, and surrounding strata Irregular vibration levels induced by train operation with different loads, which included the normal load and peak load, were applied to the rail Stress, vertical and radial displacement, and particle acceleration in the rail, sleeper, concrete lining, and surroundings were calculated during the numerical simulation The results revealed that with the increasing of trainload, the settlement of the rail track increases linearly The symmetrical position on both sides of the concrete lining was compared and showed that the radial displacement and hoop stress of the particles are evenly distributed The vibrational frequency of the concrete lining was closely associated with the load frequency The symmetrical trend of radial displacement of particles in the surroundings showed that the value decreased with increasing distance from the outer edge of the lining The effective distance of train irregular vibration load in the horizontal path is more than 40 m, which should be considered when an adjacent tunnel is constructed simultaneously

Impact of unused life for track sections and available workforce in scheduling tamping actions on ballasted tracks

Abstract: This paper presents an optimization model for the problem of optimal scheduling of tamping actions on ballasted tracks. The model extends an existing one in the literature by including the unused life costs for track sections in the objective function and introducing available workforce constraints in the model. The aim is to obtain an optimal schedule for tamping actions minimizing the total cost in a finite time horizon using global optimization. The results of numerical study show that consideration of track layout in the problem leads to a significant increase in the total number of tamping actions and the amount of unused life for track sections. It is also found that it is important to use a big value for available workforce in the problem in order to reduce the total cost. The proposed model presents a more realistic solution for the studied problem than the existing work in the literature.

Effect of hydrated lime on rheology, fracture, and aging of bitumen. Discussion. Authors' closure

Abstract: Hydrated lime (HL) is an active filler in some bitumens. Rheological models demonstrate that HL interacts with certain bitumens to develop an adsorbed (interactive) layer around the HL particles. The volume of this layer can be substantial, causing HL to have a much more substantial effect on the bitumen than inert fillers. The level of interaction between HL and bitumen is bitumen dependent. This interaction causes HL to strongly affect high-temperature rheology in certain bitumens, but it has less of an effect in others. The low-temperature stiffening effects of HL are less prominent, and a significant level of fracture toughening (at low temperatures) occurs through the addition of HL. The active nature of HL with certain bitumens is further verified by nuclear magnetic resonance. HL is considered a multifunctional additive with potential benefits to the binder and to the mixture that include resistance to deformation, low-temperature fracture toughening, and increased resistance to age hardening. HL may be competitive with some polymer additives.

Dynamic behaviour of ballasted railway tracks: a discrete/continuous approach

Abstract: Owing to the small number of grains in the vertical direction of the ballast layer of a railway track, a discrete/continuum double-layer model is proposed: the upper layer (the ballast) is modelled by a discrete 3D-lattice of interacting grains whereas the infinite underlayer is a continuum linear elastic medium. The problem under consideration is the dynamic behaviour of this double-layer system under the action of a moving load. A parametric study concerning the underlayer stiffness, the load velocity and the grain size is conducted. A comparison with the continuum modelling is provided for realistic moving loads.