Construction Of Road Embankments Research Articles

Secondary consolidation simulation of soft soils with vertical drains under time-dependent loading

Preloading with vertical drains is an effective ground improvement technique used to accelerate the consolidation process. Generally, embankments are constructed over a period, by increasing the fill height with time. Hence, it is not always realistic to analyze embankments as a single ramp loading or an instantaneous loading. Although, many studies have been conducted to calculate the settlement variation under time-dependent loading, those methods are complex in practical applications and do not consider the secondary consolidation settlement which is important for very soft organic soils. In this study, the original Barron’s (1948) consolidation theory is applied to calculate the variation of settlement, pore water pressure, and degree of consolidation due to incremental step loading of embankments, constructed on compressible soft organic soil, stabilized with vertical drains (Gravel compaction piles, sand compaction piles and prefabricated vertical drains). The settlement predictions are compared with the actual settlement monitoring data obtained during the construction of road embankments and pore pressure variation is compared with the results obtained from a case study reported in the literature. The comparisons show that the results obtained from the proposed method match very well with the actual field measurements.

Secondary consolidation simulation of soft soils with vertical drains under time-dependent loading

Preloading with vertical drains is an effective ground improvement technique used to accelerate the consolidation process. Generally, embankments are constructed over a period, by increasing the fill height with time. Hence, it is not always realistic to analyze embankments as a single ramp loading or an instantaneous loading. Although, many studies have been conducted to calculate the settlement variation under time-dependent loading, those methods are complex in practical applications and do not consider the secondary consolidation settlement which is important for very soft organic soils. In this study, the original Barron’s (1948) consolidation theory is applied to calculate the variation of settlement, pore water pressure, and degree of consolidation due to incremental step loading of embankments, constructed on compressible soft organic soil, stabilized with vertical drains (Gravel compaction piles, sand compaction piles and prefabricated vertical drains). The settlement predictions are compared with the actual settlement monitoring data obtained during the construction of road embankments and pore pressure variation is compared with the results obtained from a case study reported in the literature. The comparisons show that the results obtained from the proposed method match very well with the actual field measurements.

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.

An Experimental Investigation on Shear Strength and Liquefaction Response of Pond Ash for Road Embankment Construction

An Experimental Investigation on Shear Strength and Liquefaction Response of Pond Ash for Road Embankment Construction

Application of a cement–clay–air foam mixture as a lightweight embankment material for construction on soft clay

Lightweight air foam materials can be used in pavement structures, for example, as embankments and subbase and base layers. Soft clay can be mixed with cement and air foam to generate a lightweight material. However, most previous studies have presented only laboratory test results for these materials and have not shown real-world applicability. The current study aims to demonstrate the application of a cement–clay–air foam mixture as a lightweight embankment material to reduce the settlement of soft Bangkok clay foundations induced by embankment weight. An experimental investigation to determine unconfined compressive strength (qu) was initially conducted in the laboratory to establish the ideal quantities of soft clay, air foam, and ordinary Portland cement required for embankment construction using the clay mixture. A full-scale lightweight embankment of area 14 m × 14 m and height 2.5 m was constructed on an 11 m thick soft clay layer to observe embankment settlement behavior on the soft clay foundation. The qu values of the lightweight materials obtained from the site were 1.3–1.8 times higher than those in laboratory tests. The mixtures with wet field unit weights of 0.6, 0.8, and 1.0 kN/m3 exhibited qu values of 430–620 and 770–1000 kPa, respectively, higher than the standard requirements (> 100 kPa for 7 curing days and > 200 kPa for 28 curing days). Based on monitored data, the lightweight embankment reduced settlement by as much as 80 % compared with a traditional embankment. Therefore, lightweight clay materials are recommended for use in the construction of road embankments on soft clay.

Stability Analysis of Toll Road Embankment Induced by Liquefaction In Klaten Regency Based On FEM Numerical Simulation

The construction of toll roads in Klaten Regency supports community connectivity in increasing economic growth and accessibility to tourist areas around the southern part of Java Island. The location of this study is in Polanharjo District, Klaten Regency. The study area has geological conditions, sandy volcanic ash, and shallow groundwater levels and is accompanied by a history of earthquakes that have occurred greater than Mw. 5.0. These three things are triggers for liquefaction. This study discusses the stability analysis of toll road embankments at the STA. 10+724 on the construction of the Solo - Yogyakarta - YIA Kulon Progo Toll Road due to the potential for liquefaction reaching 14 meters. The road embankment construction is placed on the ground surface, which has the potential for liquefaction with a height of up to 5 meters. Calculate the safety factor using the numerical simulation finite element (Plaxis v.8.2 software) with static and pseudostatic analysis. Numerical calculations show that the stability analysis of toll road embankments placed on the ground with the liquefaction potential is still safe for construction with a safety factor on the static analysis (SF: 1.989 > 1.5) and pseudostatic analysis (SF: 1.912 > 1.1).

Comparing Several Different Numerical Approaches for Large Deformation Modeling with Application in Soil Dynamic Compaction

Dynamic compaction (DC) is vastly utilized to improve the strength characteristics of the soils. To predict the soil deformations derived from the DC operations, usually numerical simulation analysis is applied. For the conduction of such simulations, several numerical approaches with different elemental formulations can be used. From the perspective of finite element analysis (FEA), there are four main formulations including the Lagrangian, Arbitrary Lagrangian-Eulerian (ALE), Coupled Lagrangian-Eulerian (CEL), and Smoothed Particle Hydrodynamic (SPH). In this research, a comparative study has been conducted to evaluate the computational efficiency of those four approaches in the prediction of soil large deformations during the DC operations. To do this, for a DC operation executed in a road embankment construction project in China, the real field data was compared to the results obtained from the numerical simulations via the ABAQUS program. The findings demonstrate that of all those approaches, the Lagrangian approach delivers the minimum accuracy of the predicted results, albeit with the least running time. In contrast, the ALE formulation predicted closer estimations of soil deformations although it was found to be less time-efficient. Interestingly, the CEL and SPH approaches predicted the soil deformations with the maximum degree of accuracy whereas they were not as time-efficient as the Lagrangian approach. To address this issue, a hybrid model of Lagrangian and SPH formulations was constituted to satisfy the maximum accuracy with the minimum running time. Such a hybrid model is highly applicable for the accurate prediction of soil large deformations during the DC operations.

Comparison of the Number of Compactor Passes and the Constrained Modulus of a Compacted Volcanic Soil

Volcanic soil is often used as fill material in road embankment construction in Java island-Indonesia. An understanding of the engineering properties of compacted volcanic soils is needed, especially during the preliminary design phase and during the detailed design phase of the road embankment. Carrying out a field compaction trial test will significantly assist in the design of the compaction process of the road embankment construction. Selecting the correct number of passes from the compactor and the engineering properties of compacted volcanic soils can be obtained from field compaction trial tests. Constrained modulus is one of the engineering properties that can indicate the stiffness of the fill material used in a road embankment. This study aims to determine the constrained modulus of compacted volcanic soil and compare it to the number of passes of a compactor from the field compaction trial test. The volcanic soil used in this study is classified as pumiceous tuff, which is derived from older volcanic rocks. The highest value of the oedometer modulus of compacted volcanic soils is 10.38 MPa which comes from eight (8) times passes of smooth drum roller conducted on field compaction trial test.

CO2 Impact Analysis for Road Embankment Construction: Comparison of Lignin and Lime Soil Stabilization Treatments

The last decade has witnessed increased attention toward products, services, and works with reduced environmental impacts. In the field of road construction, the use of alternative materials, wastes, or by-products obtained from industries is attracting considerable interest. The Life Cycle Assessment (LCA) is a powerful project-level tool that allows the assessment of the environmental impacts of a road infrastructure, from raw materials production to end of life phase. In this study, the environmental impacts (in terms of global warming potential-GWP) of an embankment construction project are investigated by a cradle-to-gate approach. The analysis focuses on all the processes involved in the construction of an embankment section, from the base to the preparation of the pavement formation level. The results are provided for two different road types and two different stabilization methods, including the use of lignin and lime. All processes that contribute towards global warming are investigated and described in detail. The most important finding of the LCA, in terms of GWP, is that the production of materials is the phase that contributes the significant share of the total environmental impact (more than 90%) for all scenarios. The lowest production-related emissions can be recorded for the scenarios involving lignin treatment for the stabilization of the embankment body. Furthermore, the percentage increase in GWP ranges between 51% and 39% for transportation activities and 10–11% for construction activities, comparing the scenarios including lime stabilization with the scenarios involving lignin treatment.

Lightweight geo-bead fill to prevent soft ground deposit failure

As a foundation for transportation infrastructure, soft ground has limited bearing capacity and high compression. To prevent embankment failure, lightweight material is suggested. In the construction of road embankments, EPS can be regarded as an environmentally sustainable lightweight fill material. The study's goal is to create a formula for GB (Geo-bead) concrete mixing as a lightweight fill ingredient. Several tests are performed on the material specimens, including bulk density, interface shear strength, unconfined compression, and a SEM of the composite material. The tests were designed to determine the physical and mechanical qualities using GB percentages (20%, 30%, and 40%). Composite material has a lower density than compacted sand. The friction angle falls between the adhesion of GB-GB and GB-cemented sand. A ductile failure pattern develops because the bond between cement paste and GB is less than that between cement sand. The composite material's CBR passed embankment specifications. In the case of an embankment on soft soil, the 2D FEM analysis expressed settlement by compacted sand and lightweight fill material. Lightweight geo bead backfill decreases soft soil settlement, preventing failure.

Impact of road embankment construction on groundwater system in alluvial aquifers

Impact of road embankment construction on groundwater system in alluvial aquifers

Undrained response of geocell-confined pond ash samples under static and cyclic loading

In this study, the effect of geocell confinement on strength, deformation, dynamic properties, and liquefaction characteristics of pond ash samples were investigated. Pond ash was collected from the Panki thermal power station, India. The geocells were handmade with high-density polyethylene sheets. Each geocell has three equal diameter circular cells. Consolidated undrained triaxial tests were conducted on both remolded and geocell-confined ash samples of size 100 × 200 mm under static and cyclic loading conditions. The confining pressures were chosen as 50, 75, and 100 kPa, cyclic strain rates were chosen as 0.2, 0.3, and 0.4% and the frequency of cyclic loading was 1 Hz. From this experimental study, it is observed that the increase in peak deviatoric stress of geocell-confined pond ash samples is about 21% to 32% higher than the unconfined samples. The liquefaction resistance of ash samples increases 51% to 87% due to geocell confinement. Result shows that ash samples exhibit better response in terms of cohesive strength, dynamic properties, and liquefaction resistance with geocell confinement, which proves the applicability of geocell-confined pond ash as a suitable material for construction of road embankments and slopes.

Analisis Stabilitas Timbunan Tinggi Pada Mortar Busa Menggunakan Metode Elemen Hingga Pada Proyek Pembangunan Jalan Baru Batas Kota Singaraja - Mengwitani

The new road construction of Bts. Singaraja City to Mengwitani has now carried out Phase I (SC 5-6) in 2019 there is a handling of high embankments using a geogrid, a slope of 1:2 at a height of ± 20 meters. At the construction site of this road there is limited land for Right Of Way (ROW) due to hilly area conditions. To overcome this problem, it is necessary to design a road embankment construction plan from a material that is safe and light enough, lightweight foam mortar embankment has been found as an alternative method to protect against overload to the ground, with lightweight structural materials and high compressive resistance to support the load. traffic. Based on the current conditions, an analysis of the stability of the light embankment of foam mortar will be carried out as an alternative for handling high embankments with variations of the vertical slope, 1:1, 1:2 and 1:3, an analysis of the stability of the embankment using the Plaxis application. The results of the analysis show that the greater the slope used, the greater the safety factor that occurs. Based on the results of the analysis, the variation of the slope of the upright embankment collapses so that there is no safety factor

The Implementation of Industrial Byproduct in Malaysian Peat Improvement: A Sustainable Soil Stabilization Approach

Peat is a well-known problematic soil associated with poor engineering properties. Its replacement with an expensive competent foundation material is practiced for road embankment construction which is costly and causes greenhouse gas emissions. Therefore, this paper investigated the effectiveness of a byproduct from a metal industry (silica fume) to stabilize peat along with ordinary Portland cement (OPC) through a series of experimental tests. After peat-indexed characterization, a number of standard compaction and mechanical tests were performed on the stabilized and parent peat. For this purpose, nine designated mixes were prepared possessing various combinations of silica fume (SF) and 10–20% OPC. Unconfined compressive strength (UCS) and California Bearing Ratio (CBR) tests were carried out after 7, 14, and 28 days of curing to assess strength enhancement and binder effectiveness, and the microstructural evolution induced by the binders was examined with scanning electron microscopy (SEM). The analysis revealed a substantial improvement in mechanical properties with the incorporation of SF and OPC, ultimately meeting the minimum strength requirement for highway construction (i.e., 345 kPa). A peak UCS of 1063.94 kPa was recorded at 20% SF, and an unsoaked CBR value of 42.95 was observed using 15% SF and 15% OPC after 28 days of curing. Furthermore, the increasing percentage of hydraulic binders exhibited brittle, collapsible failure, while the microstructural study revealed the formation of a dense matrix with a refined pore structure in the treated peat. Finally, a significant statistical analysis was carried out by correlating the test parameters. In this way, rather than stockpiling and dumping, an industrial byproduct was implemented in peat stabilization in an eco-friendly manner.

Relationship between Phase Composition and Mechanical Properties of Peat Soils Stabilized Using Oil Shale Ash and Pozzolanic Additive

Construction of road embankments in peatlands commonly involves replacement of the peat with a fill-up soil of an adequate load-bearing capacity. This usually requires a lowering of the water level, turning a peatland from a carbon sink to a source of greenhouse gases. Thus, alternatives are sought that are less costly in both economic and ecological terms. Mass-stabilization technology can provide a cheap substitute for Portland cement. Calcareous ashes (waste materials), supplemented with pozzolanic and alkali additives to facilitate and accelerate the setting and hardening processes, are attractive alternatives to soil excavation or replacement techniques. Silica fume and waterglass were used as pozzolanic agents and KOH as a soil-alkalizing agent. X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analyses and stress–strain tests were performed for the hardened samples. Crystallization of alkali feldspars was observed in all test samples. Comparable hardening of peat soil was achieved for both ashes. It was shown that the ashes of Estonian kukersite (oil shale) from both pulverized firing and a circulating fluidized bed incineration process (produced in energy sector as quantitatively major solid waste in Estonia) can be used as binding agents for peat stabilization, even without the addition of Portland cement. Hardened peat soil samples behaved as a ductile material, and the cellulose fibers naturally present in peat gave the peat–ash composite plasticity, acting mechanically in the same way as the steel or glass fiber in ordinary reinforced concrete. The effect of peat fiber reinforcement was higher in cases of higher load and displacement of the composite, making the material usable in ecological constructions.

Numerical Modeling of Horizontally Layered Geosynthetic Reinforced Encased Stone Columns Supporting Embankment on Sabkha Soil

The present research work is concerned with the construction of road embankments on a Sabkha soil in Algeria. This soil is not only soft and very humid during the flooding seasons but also has frequent small areas of very soft soil which are called locally weak zones (LWZ) in the context of this study. LWZ are characterized by low strength and high compressibility. Two-dimensional axisymmetric analyses were carried out using PLAXIS 2D 2017. The study demonstrated that ordinary stone columns (OSC) are ineffective given the nature of these soils due to the excessive bulging caused by the lack of lateral pressure. On the other hand, the reinforced stone columns with external and internal reinforcements called as vertical encasement and horizontal strips (VESC+HRSC) are one of the best improvement methods of locally weak zones (LWZ), especially to increase the stability of embankment on the highway, namely, a much reduced bulging and a reasonable settlement, so that it is possible to build safe and very high embankments (indeed, numerical results showed for a (VESC+HRSC) combination, a vertical settlement of 0.74 m and a lateral deformation of 20.02 mm vs. 1.56 m and 221.16 mm for an OSC). Besides, an extensive parametric study was conducted to investigate the effect of the spacing of the horizontal reinforcing strips and of the column reinforced length. The influence of stone column diameter, depth of locally weak zone, and the effective stiffness of the geosynthetic, on the performance of the (RSC) - embankment composite were also investigated. The computational results are presented in the form of tables and graphs, and compared with previous published results available in the literature.

Explosive technologies in transport construction

Performing different works (construction of road embankments, canals, tunnels, moving some soil mass in a given direction), as well as construction of various towers, power transmission supports, foundations for bridge supports, special pits for anchors are carried out by explosive technologies. The paper analyzes in detail a new method of determining the boundary of the explosion excavation. Its distinguishing features are the use of an impulse-hydrodynamic model for setting explosion problems and use of boundary problems of the theory of analytical functions. The new method is used in solving the problem of determining the boundary of the ejection excavation for the case of a buried charge. The results of calculations for the main geometric parameters of the explosion are given. The prospects for the development and application of the method are discussed.

Numerical Modeling of Encased Stone Columns Supporting Embankments on Sabkha Soil

The present research work is concerned with the construction of road embankments on a specific soil called Sabkha in Algeria. This soil is not only soft and very humid during the flooding seasons but also has frequent small areas of very soft soil which we here call Locally Weak Zones (LWZ). LWZ is characterized by low strength and high compressibility. The paper presents the results of two-dimensional axisymmetric numerical analyze that were carried out using PLAXIS 2D 2017, for the modeling of an embankment supported by stone columns on Sabkha soil. The study focuses on the evaluation of the maximum bulging of the stone column and on the settlement of the embankment. It has been demonstrated that Ordinary Stone Columns (OSC) were ineffective due to excessive bulging (221.16 mm) caused by the lack of lateral pressure. On the other hand, the Encased Stone Columns (ESC) showed good behavior, namely a much reduced bulging (42.09 mm) and a reasonable settlement (0.962 m vs. 1.560 m for an OSC) so that it is possible to build safe very high embankments. The numerical analysis also shows that the length of the encasement should just be greater than the depth of the LWZ. Besides, an extensive parametric study was conducted to investigate the effects of the variations of embankment height, stiffness of geosynthetic, the depth of the locally weak zone, area replacement ratio (ARR), and the stone column friction angle, on the performance of the (ESC) - embankment composite in (LWZ). Some important guidelines for selecting the ideal encased stone column (ESC) to support embankments on over locally weak zone were established through this numerical study.

About explosive technology of building road embankments, tunnels, canals

Performing different works (construction of road embankments, canals, tunnels, moving some soil mass in a given direction), as well as construction of various towers, power transmission supports, foundations for bridge supports, special pits for anchors is carried out by explosive technologies. When carrying out excavation works related to the construction of road embankments, trenches, wells, cord charges are used. From the mathematical point of view, the calculation of such charges presents the problem of determining the movement of soil particles in the plane perpendicular to the axis of the corded charge. Calculation of geometrical characteristics of the above construction works is based on impulse-hydrodynamic setting, having “liquid” and “solid-liquid” varieties. The work gives two examples of calculations within both productions. In the first problem, within the framework of the solid-liquid model, the entire boundary of the channel is determined in the case of an explosion of a square charge, while in the second problem the explosion of two charges, when there is a circular cylinder in the ground, is investigated.

A novel approach to evaluating the compaction control of soils

Soil compaction is an important operation during the construction of road embankments, railway subgrade, earth dams and compacted clay liners for waste disposal. Soil compaction is usually controlled based on the ratio of the dry density of the soil to the soil water content. However, this relationship presents problems in both the laboratory and in the field when using excess compaction energy levels in cohesive soils with a high natural water content, including differences in the compaction energy levels and a reduction in strength as a result of over-compaction. The compaction curve, which considered the compaction energy levels, is usually unknown in the field and the main factors influencing the stiffness and strength of compacted soils are the dry density and the degree of saturation. We show here compaction results for soils in terms of the dry density and degree of saturation and introduce the concept of an optimum compaction line.