Road Embankment Research Articles

Effect of Vehicle Cyclic Loading on the Failure of Canal Embankment on Soft Clay Deposit

Road embankments along irrigation canals, constructed on soft Bangkok clay, have always been unstable. Numerous studies have shown that rapid drawdown of water level may be one of the main causes, while vehicle cyclic loading may also contribute to embankment failure. This study aims to investigate the impact of vehicle loading on the failure of embankments built on Bangkok soft clay. The behavior of soft Bangkok clay under vehicle load has been investigated by employing conventional and dynamic triaxial techniques, and finite element method (FEM). This study also examined the effects of soft clay thickness and cyclic loading with different magnitudes and frequencies. The laboratory testing results indicate that the threshold stress of the soft clay is estimated to be approximately three-fourths of the undrained shear strength of the soil. The reduction in effective stress in the soft clay is caused by varied frequencies and thicknesses of the clay. Based on the analysis results, it has been proven that the cyclic loads exerted by vehicles solely are insufficient to cause the embankment to collapse. Nevertheless, the repetitive loading of vehicles may result in a one-quarter decrease in the embankment’s factor of safety.

Geobamtile to Support Road Embankment Over Deep Soft Ground

Geobamtile to Support Road Embankment Over Deep Soft Ground

A study on settlements of road embankments on soft ground using vertical drains

In civil engineering, the study of embankment settlement on soft ground is a vital geotechnical task in order to maintain serviceability of the road embankment, pavement, and facilities. This paper presents a study on settlements of road embankment on soft ground using vertical drains, including prefabricated-vertical drain (PVD), sand drain (SD), and sand compaction pile (SCP) on a number of packages of Hanoi – Haiphong Expressway Construction Project. The effectiveness of settlement prediction of vertical drain solutions is evaluated considering the ratios between the observed consolidation settlements and settlements predicted in the Detailed Design, in relation to the thickness of soft soil and the depth of treatment. Regression analysis is used to establish the correlation between the observed settlement and the height of embankment. The results show that (i) the design generally overestimated settlements; (ii) the ratios between observed and predicted settlements tend to positively correlate with the thickness of soft soil and the depth of treatment, and (iii) there are positive correlations between the height of embankment and the observed settlement. These correlations can be a valuable source of reference for anticipating settlements in basic design of highway projects with soft ground treated by vertical drains, in the regions that have geological stratum similar to Thabinh and Haihung formations of Bacbo Plain

Experimental Study on Erosion Process of Expressway Embankment Subjected to Tsunami After Earthquake

On March 11, 2011, the Great East Japan Earthquake triggered tsunamis that reached extensive areas along Japan’s Pacific coast. There have been instances where embankments built on plains for expressways mitigated the impact of tsunami damage. In the vicinity of the Sendai-tobu highway, the presence of an embankment approximately 10 m high altered the course of the advancing tsunami, thereby preventing flooding. Establishing a multiplied defense system using road embankments necessitates understanding the deformation and collapse mechanisms of road embankments impacted by tsunamis following seismic motion. In this study, overtopping experiments were conducted by first applying seismic motion to model embankments, followed by introducing the first wave of breaking bores, and then simulating prolonged overtopping by the tsunami. The experimental findings indicated that within the embankments impacted by the tsunami, there was an immediate increase in what is presumed to be pore air pressure following the arrival of the breaking bores, followed by a rise in pore water pressure during subsequent overtopping. Moreover, embankments subjected to seismic motion exhibited accelerated erosion following the overtopping. These results imply that when embankments settle due to an earthquake, leading to relatively higher anticipated inundation depths and the potential for overtopping, it is crucial to implement measures to prevent the settlement of the crest for embankments expected to serve as part of a multiplied defense system.

Strength degradation of foamed cement paste under sulfate attack

Foamed cement paste is increasingly being applied in the construction of road embankments, bridge abutments, slope treatments, and pipeline backfilling. Constructed foamed cement paste may suffer from sulfate attacks in certain environments, such as offshore regions and salty soil areas. However, the long-term performance of foamed cement paste under such circumstances remains unclear. In this study, laboratory tests are conducted to evaluate the strength deterioration of foamed cement paste after erosion by sulfate attack. Factors influencing the density of the foamed cement paste, concentration of the sulfate solution, and cation type (i.e., Na+ and Mg2+) are considered. The results indicate that the strength of the foamed cement paste decreases with increasing immersion time. The Na2SO4 solution has a more severe erosion effect than the MgSO4 solution when other conditions remain constant. Finally, X-ray diffraction is conducted to identify the phase of the crystalline material in the specimen. This study will be beneficial in the application of foamed cement paste in regions with salt-rich soils.

Integrated approach to sustainable utilization of phosphate waste rock in road embankments: Experimental insights, stability analysis, and preliminary economic evaluation

This paper highlights an issue that has not received much attention which is the use of phosphate waste rock (PWR) in road embankments. This study focuses on the valorization of marly clay and marly limestone lithologies, which are abundant but often unused or undervalued, being simply deposited around mine sites. Investigating the potential use of these materials in road embankments requires a combination of experimentation, stability analysis, and economic evaluation. The materials were collected from mining trenches in the Benguerir mine (Morocco). The samples were subjected to i) chemical and mineralogical characterization; ii) environmental characterization; and iii) geotechnical characterization. The results of the characterization show that the samples are chemically dominated by CaO (12–33 wt%), SiO2 (23–38 wt%), and MgO (7 – 9 wt%); mineralogically, the main phases are quartz, calcite, dolomite, apatite, and clay minerals. The environmental characterization classified the studied materials as non-hazardous waste. In terms of geotechnical characterization, the marly limestone and marly clay belong to the A3 and R33 categories, which means that they can be successfully used as a sustainable alternative material for the embankment. This finding supports their safe utilization. The stability analysis reveals that embankments up to 10 m in height can be constructed with marly clay without significant physical instability risks. Satisfactory safety factors (SF) were found (SF=1.97 for H=5 m and SF=1.54 for H=10 m). For marly limestone, the height limit is less than 10 m (SF=1.74 for H=5 m and SF=1.33 for H=10 m), but it can be increased to 10 m by adding a bench of rock fill with a safety factor of 1.64. Finally, an economic evaluation demonstrates that PWR can be used as embankment materials within a radius of 28 km around the mine site. It appears to be a cost-effective alternative compared to conventional materials.

Seismic resilience evaluation of granular column-supported road embankments on liquefiable soils

In this study, the seismic resilience of granular column-supported road embankments on liquefiable soils is examined to enhance the understanding and seismic design of resilient transportation infrastructure. A nonlinear dynamic analysis of embankments on liquefiable soils is performed, and the results are validated against centrifuge test data. In the assessment, a functional analysis framework encompassing fragility, vulnerability, and restoration functions is employed to evaluate the robustness and recovery of embankments. The resilience of embankments is quantified by the comprehensive life-cycle resilience index (R), which considers various factors, such as the embankment height, the liquefiable soil thickness, and the area replacement ratio (AR) of granular columns. A simplified design method is proposed that involves a model for rapidly assessing the resilience state of embankments under varying seismic intensities. The analysis highlights the essential role of granular columns in mitigating liquefaction-induced damage during seismic events, improving robustness, and recovering post-earthquake functionality, and a practical and reliable tool is developed for assessing embankment resilience across diverse seismic scenarios.

Evaluation of the cooling performance of a crushed-rock interlayer embankment with longitudinal ventilation ducts in a pan-Arctic permafrost region

In pan-Arctic permafrost regions, longitudinal ventilation ducts are often installed in embankments to cool the underlying permafrost and thereby ensure road stability. However, the current design methods for embankments with longitudinal ventilation ducts (ED) normally simplify the conjugate heat transfer process between the duct wall and air in the duct. In this study, based on the chimney effect and the theory of fluid flow and heat transfer, we propose an improved numerical method for evaluating the cooling performance of the ED. Using this method, we conduct an assessment of the influences of duct configuration on the efficiency of ventilation duct cooling in winter. The results indicate that increasing the diameter of the duct and the height of the duct outlet can effectively improve the radial cooling range of the ventilation duct. However, the cooling performance of the ventilation duct becomes worse when the length of the duct is increased. To address the limited cooling performance of the ED, we design a crushed-rock interlayer embankment installed with longitudinal ventilation ducts (CED). It is found that the CED is more effective at maintaining the long-term thermal stability of the road in a typical pan-Arctic permafrost region when compared to the ED and the crushed-rock interlayer embankment. Furthermore, a cost analysis of the four different embankment designs reveals that the CED is a financially viable option for embankment construction in permafrost regions.

Use of Bottom Ash from a Thermal Power Plant and Lime to Improve Soils in Subgrades and Road Embankments

The present study has focused on stabilizing the soils of the embankments and improving the mechanical properties of gravel in subbases of pavements with different contents of bottom ash from thermal power plants and low percentages of lime. The density, humidity, simple resistance strength and bearing capacity of the new materials resulting from this combination have been studied. The results indicated that the optimal proportion of bottom ash added to the analyzed soil is 15%, while the optimal addition of lime is 1% for application in embankments and 2% for application in road subgrades. In clay soil that has a low simple resistance strength when 25% of bottom ash is added without lime, it can double the resistance. In the case of the gravel evaluated, it was found that the optimal ratio between the addition of bottom ash and lime is 6.5. In conclusion, it can be noted that soil that does not have any resistance when certain percentages of bottom ash are added, its properties are improved to be used in embankments.

InSAR supported by geophysical and geotechnical information constrains two-dimensional motion of a railway embankment constructed on peat

Rail and road embankments constructed on peatlands are subjected to significant challenges due to the high compressibility of peat. They are, therefore, susceptible to considerable settlement following construction. Accurate and timely monitoring of such embankments is important in order to enable proactive intervention strategies and to avoid failures. Multi-temporal Synthetic Aperture RADAR Interferometry (MT-InSAR) techniques applied to satellite-derived SAR data have been shown to be effective for remotely measuring and monitoring the deformation of civil engineering infrastructure. This paper presents a comprehensive approach, involving MT-InSAR supported by local geophysical and geotechnical information, for the detection and investigation of the movement of a railway embankment constructed on peatland. The Small Baselines approach, implemented in StaMPS (referred to as StaMPS-SB), was performed to measure long-term deformation of the embankment in vertical, horizontal east-west and satellite line-of-sight (LOS) directions. In this regard, a Sentinel-1 A/1B dataset composed of 362 descending images, acquired from 2015 to 2022, was analysed to measure LOS displacement. Also, 282 Sentinel-1 A/1B images of both ascending and descending tracks, collected from 2017 to 2022, were analysed to obtain vertical, horizontal and LOS displacements. According to the results, the maximum ground motion rate along the LOS direction was −29 mm/year for the period from 2015 to 2022. However, from 2017 to 2022, this value was about −25 mm/year and − 22 mm/year for descending and ascending tracks, respectively. During this period, the maximum motion rate obtained was −23.1 mm/year in the vertical direction. Moreover, horizontal movement up to −10 mm/year was observed in the westward direction and + 7 mm/year in the eastern direction. We used in-situ data to support corroborate and improve our interpretation of the InSAR results. In this context, peat thickness profiles, records of tamping activities and interpretations of the railway ballast base from ground penetrating radar data, were employed. The in-situ data revealed that the embankment section exhibiting the greatest vertical motion detected by InSAR corresponds closely to the thickest section of railway ballast, the zone of greatest number of tamping activities and the deepest section of peat. As such, this case study highlights how remote detection of embankment motion, coupled with targeted in-situ investigation, can underpin proactive intervention to improve safety.

Bridge Approach Model with Precast Concrete-cell Box Structure to Overcome Differential Settlement

The bridge approach road embankment has a very important role as a link between the road and the bridge. In the post-construction stage, there are many cases of bridge approach road embankments, especially those with high elevations, potentially experiencing differential settlement. To overcome this, an analysis and planning study was carried out in increasing stability and overcoming the differential decline that occurred in the bridge approach road structure, especially in the approach slab structure with the end of the bridge. So that a bridge approach road model was developed as a substitute for the mass of soil embankment by conducting experiments and making a prototype of the Precast Concrete-cell Box structure model, which was given the maximum repetition and gradual plan load. While the method used in this research is the prototype model method, by conducting loading and settlement experiments on the bridge approach, especially on the approach slab. Furthermore, analysis and simulation are carried out under the condition of reaction force and maximum loading. From the results of the analysis, in the loading test of 2,761.00 kg, 2,717.00 kg 2,974.00 kg on the prototype model, the value of the decrease in LVDT 1-2-3 was 0.00 mm, the loading test of 3,956.00 kg and 3,887.00 kg obtained the value of the decrease in LVDT 1 and LVDT 3 of 0.00 mm and LVDT 2 obtained a decrease value of -0.01 mm which indicates a bending / deflection occurs in the approach slab structure, but it is still safe and no structure is required..

Analysis of deformations of road embankments founded on displacement columns improving soft subsoil

Drilled displacement columns, constructed in the form of unreinforced or reinforced concrete elements, are currently a very commonly used method of improving soft subsoil, creating an alternative to more expensive pile foundations. A frequently used solution for improving soft soils of road or railway embankments is to design a regular pattern of columns of relatively small diameter. Columns along the perimeter of the improved area are reinforced with rigid steel profiles, while the internal ones are made as concrete elements. Column heads are usually covered with a load transfer platform (layer of compacted granular fill) which is additionally reinforced with geosynthetics. The application of soil improvement with displacement columns is not always successful. It is due to the errors and shortcomings occurring at the design stage, including simplifications in modelling, to construction faults, which may include insufficient experience of contractors and/or improper supervision. Referring to the real object that failed, the article provides the results of numerical parametric analyses taking into account the influence of the key design parameters such as: the stiffness of the load transfer layers, the amount and stiffness of the geosynthetic reinforcement as well as the column spacing. The article presents comparisons of numerical results obtained with the finite element analyses for various approaches to geometry modelling (axisymmetric, 2D and 3D). The simulations indicate that the use of the axisymmetric model of a single column in routine design may lead to the deformations exceeding the serviceability limit states.

Experimental investigation on reuse of dredged soils improved using waste rubber tyre powder (WRTP) and cement as admixtures

ABSTRACT Dredged soils possessing low-bearing capacity and high compressibility were tested incorporating waste rubber tyre powder (WRTP) at varying percentages in increments of 1.5% up to 15% by dry weight of the soil and 2% cement. It was observed that maximum dry unit weight (MDUW) decreased to 11.75 and 12 kN/m3 for combinations of 15% WRTP and 15% WRTP + 2% cement respectively. Direct shear test (DST) parameter ‘c’ at 4.5% WRTP and 2% cement increased from 44 to 49 kN/m2 whereas angle of internal friction, ‘ϕ’ showed an increase up to 37°. The Unconfined compressive strength (UCS) of soil-WRTP-cement mixture enhanced from 110 kN/m2 in the untreated state to 596 kN/m2 at 28 days curing and 6% WRTP + 2% cement. Further, California bearing ratio (CBR) values increased up to an optimum addition of 6% WRTP + 2% cement, both in unsoaked (6 to 13%) and soaked condition (2 to 7%). Soil improvement using WRTP and cement can improve the strength and durability of road subgrades and embankments. WRTP in addition to cement can be used in locations with weak or problematic soils to improve load-bearing capacity and reduce settlement-related problems.

Fragility assessment for the rainfall-induced embankments on silty soils

The fragility curve expresses the probability that an asset exceeds some serviceability state for a given level of environmental perturbation or other loadings. It is an important component in the quantitative risk analysis and resilience evaluation of infrastructure exposed to natural hazards. Incidences of over-settlement of embankments are increasingly reported due to more intense and longer-duration rainfall events. This paper develops fragility curves for the rainfall-induced embankment settlement. For this purpose, an embankment incorporating enhanced seepage and displacement analysis within unsaturated soil conditions is modelled based on a reported case history. A Monte Carlo simulation is used for rainfall infiltration and embankment deformation analysis under various rainfall scenarios. Probability values are obtained to achieve three levels of damage states in terms of road embankment settlement. The parametric analysis produces the exceedance probability curves for various rainfall intensities, saturated permeabilities and embankment slope angles. This work offers an efficient tool for assessing fragility to rainfall-induced excessive settlement of embankments.

Geotechnical Properties of Washed Mineral Waste from Grit Chambers and Its Potential Use as Soil Backfill and Road Embankment Materials

The current practice of managing washed mineral waste from grit chambers under national legislation focuses primarily on its disposal, generating high costs for wastewater treatment plants. Other ways are being sought to enable its use, especially as a by-product in the construction industry. This paper presents the results of laboratory tests of the geotechnical, physical and mechanical parameters of washed mineral waste from grit chambers. Research samples were taken from the largest, in terms of maximum daily capacity, wastewater treatment plant “Czajka” in Poland. The washed mineral waste was characterized by organic matter content (0.36% by Tyurin’s method or 1.04% by the loss on ignition method), fraction content (sand fraction was at least 90%; it corresponds in grain size to uniform-grained medium sand), specific density of solids (2.55 g/cm3), dry density, void ratio and porosity corresponding to the state of the loosest and densest possible composition of soil grains and particles (1.54 g/cm3, 0.656, 0.396 and 1.87 g/cm3, 0.364, 0.267, respectively), sand equivalent (93), passive capillarity (0.20 m), maximum dry density (1.78 g/cm3), optimal moisture content (11.23%), degree of saturation after compaction (0.66) and permeability coefficient (6.22·10−3cm/s). The mechanical parameters determined included internal friction angle (35.5°) and apparent cohesion (14.27 kPa). The possibility of using washed mineral waste as soil for the backfill of installation trenches, abutments and retaining structures, as well as road embankment material, was evaluated considering current standards and legislation. It was found that the values of the determined parameters of washed mineral waste coincide with the values of the geotechnical parameters of sand, and there is a possibility of using this waste as a material in the indicated applications after fulfilling the appropriate conditions.

Practical Optimization of Access Road Construction Methods in Soft Soil Areas

In one of the smelter projects at West Kalimantan, access road construction was planned to use soil embankment above the geo-membrane layer. But this method is not highly effective considering rainfall intensity is very high in the project location. Therefore, optimization needs to be done to obtain the most effective method in terms of cost and timely accomplishment of the access road. The optimization method is done by making a comparison matrix of the output results of the running simulation schedule on software. From the several methods proposed, the duration of completion, completion costs, and resource requirements are compared and scored to get the most optimized method. Other than that, carbon emissions resulting from each method are also compared. The optimization result concluded that boulder stone layer addition with optimum quantity in the embankment is the most optimal method considering the remaining time and encountering intensive rainfall. This optimized method can result in an accelerated construction duration of 140 days, cost efficiency of 11.46%, and a reduction in carbon emissions of 44% compared to the initial method. This optimization method is expected can be applied to access road embankment projects of soft soil areas in other locations, especially in the Kalimantan region.

The Role of Geological and Geotechnical Factors in Shale Slope Instability: Case of Landslides on Road Embankments, Tizi Ouadrene Sector - Rif Extern, Morocco

Constructing roads in geologically unstable regions such as northern Morocco poses a major challenge. The Tizi Ouadrene sector, located in the Rif External Nappe of the Rif Belt, exemplifies a significant complexity in this issue, with a risk of landslides threatening the road embankments in this area. This study aims to characterize the frequent Cretaceous shales in the study area and analyze the landslides that have occurred on the road embankments cut into these shales. It examines the role of lithology, geometry, tectonics, human activity, and water in these landslides. The geological structure of slopes and their geometric configuration are crucial factors in determining the occurrence, distribution, and other characteristics of these landslides. Defects are controlled by the relative position of sedimentary and tectonic discontinuities, as well as the relative abundance of indurated shales compared to crushed ones. Crushed shales are susceptible to rotational slides, while the indurated ones are prone to planar and wedge sliding. The latter are mainly associated with bedding planes, particularly those oriented N65-80 with slopes facing south and SSE, as well as NW-SE and NE-SW-trending fractures. Hydrological, tectonic, and anthropogenic factors also contribute to the instability.

Investigation of Shear Strength Reduction Method in Slope Stability of Reinforced Slopes by Anchor and Nail

Since the stability of slopes in infrastructures such as road and railroad embankments, excavations, and, in general, earthwork is important, analyzing the stability of these slopes has been one of the main focuses of geotechnical engineers. Although analyzing both reinforced and unreinforced slopes is needed, reinforced slopes require special attention as the reinforcement elements significantly affect the calculations. Hence, the current study’s aim is to find out the differences between obtained safety factors using the Limit Equilibrium Method (LEM) and Shear Strength Reduction Method (SSRM). For this purpose, first, the origin differences in terms of Safety Factor (SF) are theoretically determined according to basic formulas for the aforementioned techniques. Then, to verify the formula, several numerical modelings are carried out using in situ measured geotechnical data to better understand the differences in terms of safety factors. The results indicate that for the reinforced slope with an SF value of higher than 1, the SSRM provides a higher SF in comparison with the other techniques, and the origin of this difference is the definitions of the SF in the different methods.

Analisa Penilaian Kondisi Jembatan Sarolangun Batang Tembesi Dengan Metode Bridge Manajemen System (BMS)

Bridges are an important part of a road network system because they have a significant impact if the bridge collapses or if it does not function properly. A bridge is a structure that crosses a river or other traffic barrier, so the collapse of the bridge will reduce or hold back traffic, which as a result will disrupt the comfort of the public in traffic and disrupt economic relations. A bridge is a structure that crosses a river or other traffic barrier, which as a result disrupts people's comfort in traffic and disrupts economic relations (Bridge Inspection Guidelines 2012). Bridges are built so that pedestrians, vehicle or train drivers can cross these obstacles. However, it turns out that there are many types of bridges which of course vary both in terms of structure, strength and even construction costs. The main components of a bridge are the unity of the road embankment structure approaching the bridge, the sub-bridge structure and the bridge super-structure (BMS, 1993). The main objective of this research is to analyze the condition of the Sarolangun Batang Tembesi Bridge by observing it visually, assessing the technical condition of the bridge, and determining the priority order for bridge maintenance based on its condition value. However, the database results produced in this bridge management system are only limited to screening and ranking results in preparing bridge management programs (Directorate General of Highways, Bridge Management Systems, (1993), "IBMS General Procedure Guide", BMS, Department of Public Works of the Republic of Indonesia.

Analysis of Road Embankment Improvement on Soft Soil Using Foamed Mortar Lightweight Embankment

Analysis of Road Embankment Improvement on Soft Soil Using Foamed Mortar Lightweight Embankment