scholarly journals Mechanistic Mathematical Modelling of Pothole Development from Loss of Roadway Subsurface-Materials

2021 ◽  
Vol 8 (2) ◽  
pp. 170-178
Author(s):  
Okechukwu Joseph Ifeanyi Ezekwesili ◽  
Jonah Chukwuemeka Agunwamba
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Separation Of Variables ◽  
Engineering Problem ◽  
Particle Migration ◽  
Traffic Load ◽  
Internal Erosion ◽  
Load Pressure ◽  
Erosion Coefficient ◽  
On The Road

In this paper, we developed a mechanistic mathematical model. It implies the engineering problem of pothole development on roadways. The issue involves internal erosion, a decline of subsurface materials, voids creation, depression, materials damage, and potholes’ appearance on the road’s surface. Our study aims to predict why, how, and when pothole develops from the loss of roadway subsurface materials. We reviewed many sources as our first method. It involved using and adapting the guiding principles for migrating particles upwards. We then changed specific parameters, formulated our model equation, solved it using the separation of variables, and then verified it. Observations from our review show that high traffic load pressure and water must be present on the road for particle migration to occur. They generate excess pore-water pressure that enables the movement of particles upwards. Particle relocation causes voids and dislocation of materials. Results show that an increase in time, cracks, soil erosion coefficient, and a decrease in the roadway’s height led to a rise in the number of materials lost from the pavement. Our study is relevant because it will better inform road managers and modelers on potholes, and they can-do preventive measures to avert total road failure.

scholarly journals Stability Improvement Method for Embankment Dam with Respect to Conduit Cracks

2022 ◽  
Vol 12 (2) ◽  
pp. 567
Author(s):  
Young-Hak Lee ◽  
Jung-Hyun Ryu ◽  
Joon Heo ◽  
Jae-Woong Shim ◽  
Dal-Won Lee
Keyword(s):  
Large Scale ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Three Dimensional ◽  
Internal Erosion ◽  
Scale Model ◽  
Seepage Analysis ◽  
Large Scale Model ◽  
Proposed Model ◽  
Improvement Method

In recent years, as the number of reservoir embankments constructed has increased, embankment failures due to cracks in aging conduits have also increased. In this study, a crack in a conduit was modeled based on the current conduit design model, and the risk of internal erosion was analyzed using a large-scale model test and three-dimensional deformation–seepage analysis. The results show that when cracks existed in the conduit, soil erosion and cavitation occurred near the crack area, which made the conduit extremely vulnerable to internal erosion. Herein, a model is proposed that can reduce internal erosion by applying a layer of sand and geotextiles on the upper part of the conduit located close to the downstream slope. In the proposed model, only partial erosion occurred inside the conduit, and no cavitation appeared near the crack in the conduit. The results suggest that internal erosion can be suppressed when the water pressure acting intensively on the crack in the conduit is dispersed by the drainage layer. To validate these results, the pore water pressure, seepage line, and hydraulic gradient were investigated to confirm the erosion phenomenon and reinforcement effect.

scholarly journals Mechanical response and pore pressure generation in granular filters subjected to uniaxial cyclic loading

2018 ◽  
Vol 55 (12) ◽  
pp. 1756-1768
Author(s):  
Jahanzaib Israr ◽  
Buddhima Indraratna
Keyword(s):  
Cyclic Loading ◽  
Pore Pressure ◽  
Pore Water ◽  
Mechanical Response ◽  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Internal Erosion ◽  
Excess Pore Water Pressure ◽  
Excess Pore

This paper presents results from a series of piping tests carried out on a selected range of granular filters under static and cyclic loading conditions. The mechanical response of filters subjected to cyclic loading could be characterized in three distinct phases; namely, (I) pre-shakedown, (II) post-shakedown, and (III) post-critical (i.e., the occurrence of internal erosion). All the permanent geomechanical changes such, as erosion, permeability variations, and axial strain developments, took place during phases I and III, while the specimen response remained purely elastic during phase II. The post-critical occurrence of erosion incurred significant settlement that may not be tolerable for high-speed railway substructures. The analysis revealed that a cyclic load would induce excess pore-water pressure, which, in corroboration with steady seepage forces and agitation due to dynamic loading, could then cause internal erosion of fines from the specimens. The resulting excess pore pressure is a direct function of the axial strain due to cyclic densification, as well as the loading frequency and reduction in permeability. A model based on strain energy is proposed to quantify the excess pore-water pressure, and subsequently validated using current and existing test results from published studies.

scholarly journals Influence of initial fines content on fabric of soils subjected to internal erosion

2016 ◽  
Vol 53 (2) ◽  
pp. 299-313 ◽  
Author(s):  
Mao Ouyang ◽  
Akihiro Takahashi
Keyword(s):  
Pore Water Pressure ◽  
Axial Strain ◽  
Water Pressure ◽  
Internal Erosion ◽  
Experimental Investigations ◽  
Compression Tests ◽  
Fines Content ◽  
Instability Zone ◽  
Before And After ◽  
Undrained Behavior

Seepage-induced internal erosion often happens in earth structures. This paper presents experimental investigations on the influence of initial fines content on fabric of soils subjected to internal erosion. The tested materials were the binary mixtures of silica No. 3 and silica No. 8, which correspond to the coarse and fine fractions, respectively. One group of specimens was prepared with initial fines contents of 0, 15%, 25%, and 35% by weight. The undrained monotonic compression tests were performed on this group to examine the influence of fines content on the undrained behavior. The other group was prepared with initial fines contents of 15%, 25%, and 35% by weight, on which the seepage tests and subsequent undrained compression tests were carried out to demonstrate the mechanical influence of the internal erosion. The undrained behavior of the first group of specimens reveals that the presence of fines would decrease the peak and residual strengths. A comparison between the undrained behavior of soils with erosion and that of soils without erosion shows that the soils become less contractive after the internal erosion. When the axial strain is less than 0.4%, the undrained secant stiffness of soils with erosion is larger than that without erosion at the same axial strain. Meanwhile, the undrained peak strength and residual strength are larger for soils with erosion than that for soils without erosion. The less amount of excess pore-water pressure is generated during the undrained compression for the eroded soils comparing to those of the uneroded soils. Furthermore, the eroded soils show a wider instability zone than that of the uneroded soils, which suggests that the instability zone be enlarged by the internal erosion. Besides, one-dimensional upward seepage tests were performed to investigate the change of fabric of the mixed sand with 15%, 25%, and 35% fines contents due to internal erosion. The recorded microscopic images of soils before and after erosion reveal that the fabric is altered by the internal erosion.

Analytical Solution for One-Dimensional Consolidation of Soil Layer Induced by Time-Dependent Groundwater Drawdown

2013 ◽  
Vol 405-408 ◽  
pp. 83-88
Author(s):  
Jian Feng Yao ◽  
Kang He Xie ◽  
Da Zhong Huang
Keyword(s):  
Pore Water Pressure ◽  
Water Pressure ◽  
Separation Of Variables ◽  
Soil Layer ◽  
Time Dependent ◽  
Initial Time ◽  
Total Stress ◽  
One Dimensional ◽  
Factors Influencing ◽  
Groundwater Drawdown

The governing equation was formulated for one-dimensional consolidation of the soil layer induced by time-dependent groundwater drawdown. Using Duhamel's theorem and method of separation of variables, analytical solutions were developed for the problem. Based on the solutions, the consolidation behaviors of the soil layer were studied and the factors influencing the consolidation were investigated. The results show that it is necessary to consider both the changes of total stress and pore water pressure on the boundary. The greater initial time factorTvcis, the slower the rate of the consolidation is.

scholarly journals Continuum-Based Approach to Model Particulate Soil–Water Interaction: Model Validation and Insight into Internal Erosion

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 785
Author(s):  
Ahmed Ibrahim ◽  
Mohamed Meguid
Keyword(s):  
Experimental Data ◽  
Soil Water ◽  
Pore Water Pressure ◽  
Fluid Model ◽  
Water Pressure ◽  
Interaction Model ◽  
Internal Erosion ◽  
Wide Range ◽  
Particulate Soil ◽  
Soil And Water

Resolving the interaction between soil and water is critical to understanding a wide range of geotechnical applications. In cases when hydrodynamic forces are dominant and soil fluidization is expected, it is necessary to account for the microscale interactions between soil and water. Some of the existing models such as coupled Computational Fluid Dynamics–Discrete Element Method (CFD-DEM) can capture microscale interactions quite accurately. However, it is often computationally expensive and cannot be easily applied at a scale that would aid the design process. Contrastingly, continuum-based models such as the Two-Fluid Model (TFM) can be a computationally feasible and scalable alternative. In this study, we explored the potential of the TFM to simulate granular soil–water interactions. The model was validated by simulating the internal fluidization of a sand bed due to an upward water jet. Analogous to leakage from a pressurized pipe, the simulation was compared with the available experimental data to evaluate the model performance. The numerical results showed decent agreement with the experimental data in terms of excess pore water pressure, fluidization patterns, and physical deformations in violent flow regimes. Moreover, detailed soil characteristics such as particle size distribution could be implemented, which was previously considered a shortcoming of the model. Overall, the model’s performance indicates that TFM is a viable tool for the simulation of particulate soil–water mixtures.

scholarly journals An Experimental Study on Dynamic Model Groove Under Shock Excitation

2019 ◽  
Vol 13 (1) ◽  
pp. 229-237
Author(s):  
Changmin Yang ◽  
Tongfei Hou ◽  
Bing Cui ◽  
Jiaqi Lou
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Single Point ◽  
Soft Clay ◽  
Traffic Load ◽  
Loading Frequency ◽  
Soil Pressure ◽  
Shock Excitation

Introduction: Variation laws of dynamic response and settlement deformation at different depths of soil roadbed were investigated and summarized in this study through a simulation test with a dynamic model groove in soft clay foundation of low road embankment. Materials and Methods: In this test, the traffic load was simulated by single-point and double-point shock excitation. Besides, loading frequency, intensity and duration were adjusted by a single variable control method. Research results show that peak values of soil pressure and pore water pressure decrease with the increase of buried depth, but they are unrelated to loading intensity and frequency. Conclusion: Nevertheless, settlement deformation does not increase linearly with the increase of frequency or time difference. The accumulative settlement at a depth varies as the loading time increases.

scholarly journals ANALISIS STABILITAS TIMBUNAN (MAINDAM) BERDASARKAN DATA INSTRUMEN GEOTEKNIK PADA BENDUNGAN SINDANG HEULA SERANG BANTEN

2021 ◽  
Vol 3 (1) ◽  
pp. 48-58
Author(s):  
Nanang Sutisna ◽  
M. Ichwanul Yusup ◽  
Euis Amilia Euis Amilia
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Field Studies ◽  
Internal Erosion ◽  
Embankment Dam ◽  
Support Tool ◽  
The Core ◽  
Conducting Research ◽  
The Stability

The development of science and technology has obtained supporting technology for monitoring the soil shear force and pore water pressure in the dam, the presence of shear forces against the landfill and pore water pressure through small cavities in the embankment soil in the dam body which can be detected by equipment such as inclinometer and piezometer that have been installed at predetermined points. The application of inclinometer and piezometer technology is used as a support tool for monitoring the movement of landfill and pore water pressure against dams. The embankment dam is the most complex of civilian structures and is very dangerous if damaged. When there is damage to a dam, it will cause a big disaster for the areas that are downstream of the dam. Damage or collapse of a dam can occur due to several things, including overtopping, sliding of the dam slopes (internal erosion or "piping"), and the occurrence of structural degradation of each zone. on the dam body. In the analysis of the stability of the embankment (maindam) which is based on geotechnical instrument data, it must be carried out as carefully and accurately as possible. The purpose of this analysis is to measure the early damage in the main dam (maindam). After conducting research and field studies at the Sindang Heula dam, there were several points of decline at the top of the core embankment (maindam). To find out the cause of the decline, data was taken from measuring geotechnical instruments.

TIME TO THE END OF PRIMARY CONSOLIDATION (EOP) OF SOFT CLAYEY SOILS: CONCERNING THE EFFECT OF ATTERBERG’S LIMIT AND CYCLIC LOADING HISTORY

2019 ◽  
Vol 128 (2B) ◽  
pp. 29-41
Author(s):  
Trần Thanh Nhàn
Keyword(s):  
Cyclic Loading ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Clayey Soils ◽  
Loading History ◽  
Cyclic Shear ◽  
Wide Range ◽  
Primary Consolidation ◽  
Time Required

In order to observe the end of primary consolidation (EOP) of cohesive soils with and without subjecting to cyclic loading, reconstituted specimens of clayey soils at various Atterberg’s limits were used for oedometer test at different loading increments and undrained cyclic shear test followed by drainage with various cyclic shear directions and a wide range of shear strain amplitudes. The pore water pressure and settlement of the soils were measured with time and the time to EOP was then determined by different methods. It is shown from observed results that the time to EOP determined by 3-t method agrees well with the time required for full dissipation of the pore water pressure and being considerably larger than those determined by Log Time method. These observations were then further evaluated in connection with effects of the Atterberg’s limit and the cyclic loading history.

Conjectures, Hypotheses, and Theories of Drumlin Formation (In memory of Stanislaw Baranowski)

1981 ◽  
Vol 27 (97) ◽  
pp. 503-505 ◽  
Author(s):  
Ian J. Smalley
Keyword(s):  
Shear Strength ◽  
Pore Water ◽  
Stress Level ◽  
Critical Stress ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Glacial Till ◽  
Forming Process ◽  
Stress Levels

AbstractRecent investigations have shown that various factors may affect the shear strength of glacial till and that these factors may be involved in the drumlin-forming process. The presence of frozen till in the deforming zone, variation in pore-water pressure in the till, and the occurrence of random patches of dense stony-till texture have been considered. The occurrence of dense stony till may relate to the dilatancy hypothesis and can be considered a likely drumlin-forming factor within the region of critical stress levels. The up-glacier stress level now appears to be the more important, and to provide a sharper division between drumlin-forming and non-drumlin-forming conditions.

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