Bed Deformation Research Articles

Vertically layered flow structure at confluence of a reservoir and tributary carrying high sediment loads

Enhanced understanding of flow structure at a river confluence is essential for predictions of sediment transport and morphological evolution. To date, however, the confluent flow structure of a reservoir and tributary carrying high sediment loads has remained poorly understood, and may be vertically layered sharply, featuring subaqueous sediment-laden flow, i.e., turbidity currents underneath subaerial clear water. Here a recently established 2D double layer-averaged model, able to resolve the formation, propagation, and recession of turbidity currents, is used to investigate a series of idealized laboratory-scale cases and a prototype case study of the Guxian Reservoir on the Yellow River, China. Four primary patterns of the stable, vertically layered flow structure at a reservoir-tributary confluence are identified: 1) single layers of sediment-laden inflow in both the main channel and tributary, sustained by sufficient vertical mixing; 2) a double layer in the main channel and a single layer of sediment-laden inflow in the tributary, when the sediment-laden flow in the tributary suffices to block intrusion of flow in the main channel; 3) a single layer of sediment-laden inflow in the main channel and a double layer in the tributary, induced by the intrusion of sediment-laden flow from the main channel into clear-water flow with small discharge in the tributary; and 4) double layers in both the main channel and tributary, which may be further divided into three subpatterns, as turbidity current exists in both the main channel and tributary, or in the main channel (tributary) intruding into the tributary (main channel). In response to unsteady discharge and sediment inputs from upstream, the vertically layered flow structure evolves in time, and may fall into one of the patterns identified above. Although bed deformation in the long term may modify the confluent flow, the vertically layered flow pattern remains so far as the present cases are concerned. The findings have implications for sediment transport and morphological evolution at a reservoir–tributary confluence, for which further studies are suggested to inform the optimization of reservoir operation schemes to mitigate capacity loss caused by sedimentation.

Promises and uncertainties in remotely sensed riverine hydro‐environmental attributes: Field testing of novel approaches to unmanned aerial vehicle‐borne lidar and imaging velocimetry

AbstractRecent advancements in remotely sensed techniques have markedly expanded data acquisition potential in riverine studies, but the techniques' applicability must be validated and improved because of uncertainties associated with diverse field conditions. This study is the first experimental evidence of using a newly designed unmanned aerial vehicle (UAV)‐borne green lidar system (GLS) and deep learning‐automated space–time image velocimetry (STIV) for remote investigation of hydraulic and vegetation quantities of the gravel‐bed Asahi River in Okayama Prefecture, Japan. In addition to identifying bed deformation in waters shallower than 2 m, the GLS point clouds characterized the submerged infrastructure with block detailing patterns, thereby identifying positional displacement and severely damaged parts. This paper also presents a noncontact method of estimating incremental river discharge. Compared to benchmarked flow model estimates, remotely sensed discharges for three transects covering shallower, deeper, and partially submerged woody vegetation areas were overestimated by 1–11%, with 4% underestimation for another cross‐section. The STIV analysis also showed complicated flow patterns that were reasonably confirmed by flow vectors from depth‐averaged modeling. Ultimately, depth‐averaged flow model estimates validated hydraulic parameters derived remotely from GLS and STIV, and vice versa. In addition to approximating vegetation growth rates, the study using GLS attributes accurately identified riparian vegetation types as herbaceous (70%), woody (86%), and bamboo groves (65%). Finally, our findings provide insight into the management of shallow clear‐flowing vegetated rivers and remote sensing of streamflow to validate hydrodynamic‐numerical methods.

Оценка параметров руслового процесса в условиях изменения гидравлического режима

Introduction. The authors address the development of river bed deformations under the influence of a water flow in conditions of a changing hydraulic regime and scroll-bar riverbed processes. The relevance of the publication is explained by the unavailability of reliable waterbed shape forecasting methods needed to ensure their normal ecological condition. Meanwhile, the analysis of the motion of solid particles is associated with the sediment flow rate at the level of saltation, and with hydraulic friction losses at the level of microforms. New dependences are proposed for the sizes of bedforms, depending on the parameters of a streamflow. Materials and methods. The influence of factors in the form of new dependencies has been proven on the basis of the study of recent and classical research works, an experimental study of the formation and development of the bottom relief in case of a change in the hydraulic regime of the streamflow. Results. The author has studied the reasons and conditions for the formation and development of bedforms at the initial stage of interaction between the flow and the riverbed, as well as the factors influencing the formation of the bottom relief which is initially smooth. Structural levels of the waterbed evolution process have been analyzed. The experimental data were analyzed to identify a universal correlation between the flow parameters and the height of the developing bottom microrelief elements, from which the resistance formula is derived that coincides with the Knoroz dependence for steepness of bedforms that complies with the Boussinesq dependence. Conclusions. The results of this study can be used to prognosticate the riverbed evolution process in case of changing hydraulic regimes of water flows in the waterbed, composed of erodible soil not only at the initial stage of formation of bedforms, but also in the course of the bottom relief development.

Numerical simulation of bank erosion and accretion in a braided reach of the Lower Yellow river

The braided reach of the Lower Yellow River (LYR) often experienced dramatic channel evolution during flood seasons, with both bed and bank deformations occurring simultaneously, which led to several negative effects such as land loss, channel migration and overbank flooding. A coupled one-dimensional model was proposed to simulate both bed evolution and bank deformation, including three modules of flow-sediment transport, bed deformation, and bank erosion and accretion. The proposed model was applied respectively to simulate the longitudinal and lateral channel deformations in the braided reach in the years of 2018 and 2006, in order to conduct detailed processes of model calibration and verification. The results indicate that: the proposed model can accurately simulate the flow and sediment transport processes, and the majority of the Nash-Sutcliffe efficiency coefficients (NSEs) were larger than 0.60 between the calculated and measured hydrographs of water discharge, water level and sediment concentration at different sections, with the maximum value up to 0.96; the calculated erosion and accretion widths of the riverbanks closely agreed with the measured data, and the absolute errors between the calculated and measured post-flood reach-scale bankfull widths were 18 m in 2018 and 14 m in 2006, with the relative errors of 1.7% and 1.3%; the effects of riverbank deformation on sediment discharge, flow velocity and channel deformation were also analyzed, which indicate that the module of riverbank erosion and accretion can play a significant role in predicting hydrodynamic and morphodynamic processes in the braided reach of the LYR.

Channel Bed Deformation and Ice Jam Evolution around Bridge Piers

The interaction between the evolution of an ice jam and the local scour at bridge piers becomes much more complicated due to the evolution of both the channel bed and ice jam. Thus, research work regarding this topic has been hardly conducted. In the present study, experiments under different flow conditions with three different pier shapes were carried out. Through laboratory experiments, the development of scour holes around bridge piers under open flow, ice-covered, and ice-jammed flow conditions was compared. The results show that under the same hydraulic condition and with the same ice discharge rate (Qi/Q), the development of an initial ice jam with a local scour around bridge piers along the entire flume takes a relatively short time. However, it takes a longer time for an ice jam to achieve an equilibrium state. With the presence of a local scour at bridge piers, after an ice jam reaches an equilibrium state, the ice jam thickness, water level, and water depth for flow are relatively larger compared to that without a local scour at the pier. The equilibrium ice jam thickness around the pier is negatively correlated with the initial flow Froude number. When the development of an initial ice jam is dominated by a mechanical thickening process, the rate of the development of a scour hole around a pier is faster. On the other hand, when the development of an initial ice jam is dominated by a hydraulic thickening process, the development of a scour hole around a pier can be treated as a scour process under an ice-covered flow condition. An equation was developed to determine the scour depth around a pier under an ice-jammed flow condition by considering related factors such as the flow Froude number, ice jam thickness, and ice discharge rate. The results of this research can provide a reference for bridge design and safety protection, as well as the interaction mechanism of local scour and ice jam evolution.

The use of backfilling to remediate sand motion issues around vibrating monopile foundations

Backfilling, as a common remedial countermeasure, is widely used in ocean engineering to address the scour or subsidence problem around offshore-structure foundations. However, the performance of the backfilling in solving subsidence problems around vibrating monopiles has not been studied, and the mixing mechanisms of the backfilling sand with the bed sand around the vibrating monopile remains unknown. To investigate these issues, an experimental study on characteristics of sand motions around vibrating monopile foundations after backfilling process is conducted. The experiments were designed in two-dimensional conditions and different particle sizes of backfilling sand were used. The time-dependent characteristic geometrical dimensions of the sand bed deformation around the vibrating monopile were measured, and the mean convective velocity around the vibrating monopile was measured by Particle Imaging Velocimetry (PIV) technology. The experimental results indicate that backfilling sand with a larger particle size can effectively reduce the depth of the subsidence hole and mitigate the sand convective velocity around the vibrating monopile, compared with backfilling material of smaller or the same size as the original sand bed. The findings of this study could help to develop effective remedial countermeasures to deal with the soil subsidence problems around the monopile foundations of offshore wind turbines.

Coupled modelling of flow and non-capacity sediment transport in sewer flushing channel

Flushing is cost-effective for mitigating sediments and constraining environmental problems in sewer systems. Previous mathematical models are almost exclusively built upon simplified governing equations evoking the assumptions of slow bed evolution and sediment transport capacity, of which the applicability remains open to question. Here a 1D coupled non-capacity model is presented for non-uniform sediment transport in sewer flushing channels, as adapted from recently established shallow water hydro-sediment-morphodynamic models for fluvial processes. The present model is tested for an experimental flushing case in Paris's Des Coteaux catchment system. The computational results agree with observed data more closely than those of a previous decoupled capacity model. While the differences between decoupled and capacity models and the present coupled non-capacity model are minor for flushing processes of short-durations, they are more pronounced for sustained long-duration flushing processes. Physically, the adaptation of suspended sediments to capacity regime cannot be fulfilled quickly, though bedload sediments can adapt to capacity regime instantly. Also, the bed deformation rate is comparable to its counterpart of the flow depth. Therefore, coupled non-capacity modelling is suggested for general applications to sewer flushing channels, of which the computing cost is essentially equivalent to simplified models built upon decoupling and capacity assumptions.

Modeling of Powder Bed Deformation in the Binder Jetting Technology

Modeling of Powder Bed Deformation in the Binder Jetting Technology

EVALUATING THE INFLUENCE OF TRAIN AXLE LOAD ON RAILWAY BALLAST DEGRADATION AND AXIAL DEFORMATION

Degradation and axial deformations of railway ballast bed are highly influenced by stresses induced by moving trains. Hence, this study evaluate the influence of train axle load on the rate of degradation and axial deformation of railway ballast bed. Series of cyclic loading test were conducted at intervals of 200,000 load cycles up to 1,000,000 cycles. Two trains with capacities of 30 ton and 24 tons for freight and passengers respectively were simulated at a typical moving speed of 120 km/hr which is equivalent to a frequency of 16.5 Hz. It was observed that with an increase in both axle load and number of load cycles, the degradation index and the axial deformation increased. It was also observed that ballast degradation has a strong influence on the ballast bed deformation. Hence, ballast degradation is highly influenced by train axle load and the axial deformation of the ballast bed has a strong correlation with the rate of ballast particles degradations

Two-dimensional modeling of channel evolution under the influence of large-scale river regulation works

In the middle and lower reaches of alluvial rivers, various kinds of river regulation projects affecting natural channel evolution often are distributed due to the requirements of flood control, navigation, and channel stability. However, the influence of large-scale river regulation works on fluvial processes is not fully known. Therefore, a two-dimensional (2D) morphodynamic model has been improved to address this problem. The new detailed procedure is presented in this paper: (i) First, each node in the study domain was labeled using a specified point code to distinguish the zones with or without regulation works; and (ii) second, a 2D model was improved to consider the effect of river regulation works. In the refined model, the modules of sediment transport and bed deformation were treated separately in different zones. In the unprotected zones, both bed deposition and erosion were likely to occur. In the protected zones, bed erosion could not occur owing to the protection provided by the river regulation works, unless there was a deposition layer newly formed over the previous simulation periods. The observed data of the years 2004 and 2008 were used to calibrate and verify the improved 2D morphodynamic model which was applied in a 68-km-long reach of the Middle Yangtze River. Satisfactory results were obtained indicating that the improved model can better simulate the process of sediment transport and the morphology adjustment in three central bars in the study reach.

Sediment budget and riverbed deformation in the uppermost part of the lower Yangtze River, China

The Yangtze River (YR), similar to most large rivers in the world, has experienced significant changes in its depositional environment due to anthropogenic disturbances and climatic influences in recent decades. However, knowledge of how the river channel and bed deformation respond to these changes in the uppermost part of the lower YR, a 200-km-long branched channel, is limited. In the current study, historical bathymetric data collected from 1992 to 2013 and high-resolution multibeam echo sounder (MBES) data obtained from 2015 to 2016 were analyzed to address the changes in the depositional environment. The results indicate that the whole riverbed in the Hukou to Datong reach (HDR) has been scouring over the past two decades and this trend is expected to continue in the future due to decreasing sediment supply from the upper watershed. The amount of net erosion from the HDR during 1992–2013 approximately accounted for 7.2% of total sediment load in the Yangtze River (5.02 billion metric tons at Datong). The evolution of the riverbed is trending towards stabilization even though the patterns of erosion and/or deposition in the HDR have dramatically changed in the last two decades. The part of the channel from the upper 100 km to Datong was found to be a sensitive reach that first showed erosion from 1992 to 2003 and showed deposition during 2003–2008, and then mild erosion during 2008–2013 in response to environmental changes. Thus, the findings indicate that riverine channel deformation in response to anthropogenic disturbance and climate influence is dynamic in different reaches, and this finding has both scientific and practical significance in terms of understanding channel stability and its response to external stressors.

A case study of newly tunnels over-crossing the existing subway tunnels

Due to the continuous expansion of congested urban areas, many new tunnels are inevitable to over-cross the existing subway lines and may even affect the operation of existing lines. It is vital to investigate the response of existing tunnel caused by over-crossing tunneling. In this study, a case history of closely spaced twin tunnels excavated above the existing tunnels in soft soil stratum was presented. The deformation of the existing tunnels induced by the excavation of the new tunnels was automatically monitored. In-situ monitoring results showed that the vertical displacement of the existing tunnels was mainly uplift and its development showed obvious phase characteristics. The increase rate of the vertical displacement in Phase I and II induced by the second over-crossing was smaller than that of the first over-crossing. A superposition method was employed to describe the uplift section characteristics of the existing tunnels. The influence ranges of tunnel excavation on the left and right lines of the existing tunnels were approximately 5.5D and 4.5D, respectively. The torsional deformation of the rail bed and the convergence of the existing tunnels are explored, and the reasons for the changes of the over-crossing sections are analyzed at the same time.

Experimental study and discrete element analysis on lateral resistance of windblown sand railway

The lateral resistance of ballast bed is an important parameter to prevent track expansion and maintain track stability. The invasion of sand particles can cause the change of lateral resistance of ballast bed and affect the stability of track structure, but little attention has been paid to the change characteristics of nonlinear lateral resistance of sandy ballast bed. In this paper, the field tests on the lateral resistance of windblown sand ballast bed were carried out to establish a multiscale three-dimensional discrete element model of sleeper-ballast bed. A systematic analysis on the evolution of lateral resistance, resistance to lateral deformation, micro-contact characteristics and lateral stability of ballast bed is performed. The results show that sand intrusion can increase the lateral resistance of ballast bed, which is approximately 40 % higher than that of clean ballast bed. In nonlinear strengthening stage and yield stage, the enhancement effect of sand particles on the lateral resistance of ballast bed is relatively weaker in comparison with the linear growth stage. With the increase in sand intrusion depth, the lateral resistance and resistance work of ballast bed both gradually go up, and the contribution of ballast shoulder to lateral resistance tends to play a leading role. Sand intrusion can increase the lateral stiffness of ballast bed and reduce the elasticity of track structure. Therefore, the maintenance operation should be carried out in time for the section with severe sandstorm.

Distribution and gas exploration of the strike–slip faults in the central Sichuan Basin

The Sichuan Basin has abundant oil and gas resources and it has been generally acknowledged as a super petroliferous basin. In recent years, immense exploration and development potential of deep natural gas emerges in the Sichuan Basin. The identification of strike–slip faults and their reservoir controlling effects are of great significance to develop a new exploration domain of fault-controlled gas reservoirs. In order to clarify the distribution of strike–slip faults in the Sichuan Basin and their relationships with natural gas exploration, in view that the strike–slip faults in this basin are small and complex with poor seismic data and influenced more by the fold deformation of Triassic gypsum salt beds, this paper identifies strike–slip faults and analyzes their characteristics, distribution and genesis based on the interpretation of continuous 3D seismic data of the central Sichuan Basin. Then, the fault-controlled gas reservoir model of strike-slip fault is established by reviewing old wells and evaluating geological conditions of hydrocarbon accumulation. Finally, the exploration potential and exploration direction of fault-controlled gas reservoirs are discussed. And the following research results are obtained. First, intraplate weak strike–slip faults can be identified by combining the seismic profile marker of strike–slip fault with the plane marker. Second, eight large strike–slip fault zones with a total length of 1280 km are identified and confirmed in the central Sichuan Basin. Third, strike–slip faults are mainly distributed in the Sinian–Permian System, mainly composed of small-displacement oblique faults and echelon faults, and different in stratification, grading, classification and segmentation. Fourth, under the control of the oblique subduction of the Proto-Tethys Ocean and the different structures of the basement, the strike–slip faults in the central Sichuan Basin were formed in the Sinian and there are multiple stages of inherited Caledonian–Hercynian activities. Fifth, the strike–slip faults in the central Sichuan Basin play a role in source–reservoir connection, reservoir stimulation, and gas accumulation and high yield, and constitute the fault-controlled natural gas accumulation system of “three-element controlling reservoir and composite hydrocarbon accumulation” based on source rock, fault and reservoir. In conclusion, a large intraplate strike–slip fault system is developed in the Sichuan Basin, which has the geological conditions of hydrocarbon accumulation to form strike–slip fault-controlled large gas field, and the large source connecting strike-slip fault zones are the main breakthrough directions of natural gas exploration in fault-controlled carbonate rocks.

Sediment transport and morphological changes in shallow flows modelled with the lattice Boltzmann method

A novel form of the lattice Boltzmann method for sediment transport and morphological changes is developed and implemented. The depth averaged shallow water equations (SWE) have been used to reach the flow pattern, the advection–diffusion equation (ADE) was exploited to determine sediment concentration in the water, bed load was determined by the active layer mass conservation equation (ALMC), while the morphological changes of the river bed were determined by the global active layer mass conservation equation (GALMC), the Exner equation. The SWE are solved by the multiple-relaxation-time lattice Boltzmann method, (MRT-LBM), while the Bhatnagar-Gross-Krook (BGK-LBM) approach has been used for solving the ADE, ALMC and GALMC. New forms of the equilibrium function for solving the ALMC and GALMC are presented, using the D2Q9 lattice. Dedicated sediment-related equations are created for each sediment-size class. Additional dedicated terms in the transport equations take care of particle exchange between the suspension and the river bed, as well as of river bed deformation. The model has been verified on a experimental section of the Danube river. The results have been compared to the measured ones, and to the results obtained by the finite difference method (FDM). Very good agreement between the results is achieved, indicating that the LBM can be successfully used for simulation of flow and sediment related processes in natural watercourses, characterized by complex geometry and morphology, and lack of uniformity in sediment composition.

A new formula for predicting movable bed roughness coefficient in the Middle Yangtze River

Computing movable bed roughness plays an important role in the modeling of flood routing and bed deformation, and the magnitude of movable bed roughness is closely associated with complex bedform configurations that change with the sand wave motion. The motion of sand wave is dependent on the incoming flow and sediment conditions and channel boundary. After the operation of the Three Gorges Project, the flow and sediment regime changed remarkably in the Middle Yangtze River (MYR), followed by significant channel adjustments. A dramatic decrease in sediment concentration caused continuous channel degradation and significant variations in cross-sectional profiles of the MYR. These adjustments in the channel boundary influence the motion of sand wave, which can further affect the magnitude of movable bed roughness. A new formula for predicting the movable bed roughness coefficient is developed, which can be expressed by a power function of both Froude number and relative water depth. The proposed formula was first calibrated using 1266 datasets of measurements at five hydrometric stations in the MYR during 2001–2012. A back-calculation process shows that the roughness coefficients calculated by the proposed formula agree well with the observations, with the determination coefficient being equal to 0.88. The proposed formula was further verified using 651 datasets of measurements at these hydrometric stations during 2013–2017. Furthermore, four common roughness formulas selected from the literature were tested for comparison. The results indicate that the calculation accuracy of the proposed formula is significantly higher than that of the previous formulas, and the Manning roughness coefficients predicted by the proposed formula have the errors less than ±30% for 96% of the datasets. Therefore, the new bed roughness predictor proposed in this study can accurately calculate the roughness coefficients straightforwardly without iterative solution and graphical interpolation, and the parameters required in the roughness predictor are easily obtained from the hydrometric observations.

Shear Variation at the Ice‐Till Interface Changes the Spatial Distribution of Till Porosity and Meltwater Drainage

AbstractMany subglacial environments consist of a fine‐grained, deformable sediment bed, known as till, hosting an active hydrological system that routes meltwater. Observations show that the till undergoes substantial shear deformation as a result of the motion of the overlying ice. The deformation of the till, coupled with the dynamics of the hydrological system, is further affected by the substantial strain rate variability in subglacial conditions resulting from spatial heterogeneity at the bed. However, it is not clear if the relatively low magnitudes of strain rates affect the bed structure or its hydrology. We study how laterally varying shear along the ice‐bed interface alters sediment porosity and affects the flux of meltwater through the pore spaces. We use a discrete element model consisting of a collection of spherical, elasto‐frictional grains with water‐saturated pore spaces to simulate the deformation of the granular bed. Our results show that a deforming granular layer exhibits substantial spatial variability in porosity in the pseudo‐static shear regime, where shear strain rates are relatively low. In particular, laterally varying shear at the shearing interface creates a narrow zone of elevated porosity which has increased susceptibility to plastic failure. Despite the changes in porosity, our analysis suggests that the pore pressure equilibrates near‐instantaneously relative to the deformation at critical state, inhibiting potential strain rate dependence of the deformation caused by bed hardening or weakening resulting from pore pressure changes. We relate shear variation to porosity evolution and drainage element formation in actively deforming subglacial tills.

Interaction between gravel mining pits and river curvature on maximum scour depth through 2D hydraulic modelling

To investigate the interacting effects of rivers curvature and gravel mining pits on rivers morphology, channels with different curvatures were analyzed using a 2D-3D modelling approach implemented through the code CCHE2D. A parameter (Δ: the maximum channel scour depth with existence of pit minus the maximum scour depth without pit) was defined as the net effect of gravel mining pits. The results indicated that the net effect of a pit on the maximum scour depth, from a straight channel to a channel with the curvature (C/L) of 2.38, decreases, and then, increases with higher degrees of curvature. The study of influential parameters showed that the cause of this event is due to the simultaneous effects of two opposing phenomena; while one (smoothing) reduces the Δ, the other (secondary flow) increases it. The reducing effect (smoothing) stems from the asymmetry of the flow velocity in the channel bend. This causes bed deformation in a way that channel experience a gradual decrease in velocity and as a result, less sediment loss. Furthermore, the boosting effect goes back to the existence of secondary flow in the bends, which grows stronger as the amount of curvature increases.

Case Study: Forecasting the Lower Vistula Bed Deformation without and with Development of Dam Cascade

The case study presents the results of numeric simulations of deformations of Vistula River bed downstream the Włocławek Dam, with and without development of the downstream dam cascade. Calculations were performed using a one-dimensional flow model MIKE11 with a river transport module. Using synthetic inflow hydrographs, predictions were performed for 39 year period (2016–2055). Results indicate that the construction of the dam cascade will reduce the erosion of the river bed downstream the Włocławek dam.

Characterisation of Geogrid and Waste Tyres as Reinforcement Materials in Railway Track Beds.

The engineering behaviour of ballast is an important factor to determine the stability and safety of railway tracks. This paper examines the stress–strain, shear strength, peak deflection stress and reinforcement strength ratio of different reinforcement materials and reinforcement locations in ballast track bed layers based on large scale static triaxial shear tests. The results show that geogrid and waste tyre reinforcement have a significant effect on the peak deviator stress of railway track bed layers and the stress–strain relationship is strain-hardened. The peak deviator stress and shear strength of geogrid reinforcement are greater under the same conditions compared with waste tyres. The reinforcement of geogrid and waste tires increases the shear strength of the track bed significantly. The more layers of geogrid reinforcement, the more energy is required for the deformation of the track bed. The energy required for deformation is greater in the centre of the waste tyre than in the other reinforced forms, and the energy required for deformation is minimal in the fully reinforced form. Excessive tyre reinforcement changes the stiffness of the track bed layer, leading to an increase in the settlement rate. The reinforcement strength ratio between geogrid and waste tyre increases significantly with the increasing of the confining pressure and reinforcement layers. Moreover, the reinforcement strength ratio of the geogrid is significantly higher than that of the waste tyre.