Embankment Loading Research Articles

Field investigation on the performance of low-carbon MgO-carbonated composite piles for ground treatments

Carbonation technology using MgO and CO2 has been considered a rapid, effective, and environmentally friendly method for improving weak soils, mainly applied in shallow foundation treatments. This study introduced a novel MgO-carbonated composite pile (MCP) technique developed by injecting CO2 through a gas-permeable pipe pile into a MgO-mixing column for carbonation and solidification and its applications in weak subgrade treatments. Several field tests were carried out to study the characteristics of MCP as well as the performance of the MCP-reinforced foundations, including carbonation reaction temperature monitoring, pore-water pressure monitoring, standard penetration tests (SPT), unconfined compressive strength (UCS) tests, static load tests, and subgrade deformation monitoring. Results showed vigorous and uniform carbonation within the MgO-mixing column, confirming the feasibility of constructing large-diameter MgO-mixing columns. The distribution, evolution, and affected zone of excess pore-water pressure induced by MCP installation were determined. The MCP exhibited good pile quality, with average SPT-N and UCS values of 39 and 1021 kPa, respectively. MCP’s bearing capacity was superior to pre-stressed high-strength concrete pipe piles, with ultimate vertical and lateral bearing capacities of 1920 kN and 119 kN, respectively. The MCP-reinforced foundation exhibited a small settlement of 54.5 mm under embankment loads. Life cycle assessment indicated significant carbon reduction benefits for MCP, with 44.7% lower carbon emissions compared to traditional composite piles.

Transformer-based settlement prediction model of pile composite foundation under embankment loading

Pile composite foundation (PCF) is a common method for treating weak foundations, with settlement being the primary indicator in its design. However, accurately and quickly obtaining PCF settlement remains challenging. This study proposes a transformer-based PCF settlement prediction model under embankment loads (PCFFormer model), which enables efficient and accurate predictions of PCF settlement across various embankment environments and pile schemes. To establish and validate the data-driven PCFFormer model, this study also developed an automatic modeling and data processing program for PCF based on the Abaqus platform. Furthermore, a large-scale dataset of PCF finite element models under embankment loads was constructed and released, which is currently the largest publicly available dataset of PCF finite element models. Additionally, this study introduces a data augmentation method that fully utilizes the finite element analysis process data, significantly improving the efficiency of creating the PCF settlement dataset. By comparing the PCF settlement predicted by the PCFFormer model with the results of finite element analysis and the predictions of other machine learning methods, the accuracy and superiority of the PCFFormer model are demonstrated. The study further discusses the impact of missing individual parameters in cushion and soil layers on the prediction accuracy of the PCFFormer model.

Consolidation of unsaturated composite foundation reinforced by T-shaped deep cement mixing piles

T-shaped deep cement mixing piles are variable section piles designed to reinforce unsaturated composite foundation under the embankment loading, which can effectively reduce regional settlement and construction costs. However, how to calculate the consolidation settlement of the reinforced ground is unclear when considering the T-shaped deep cement mixing piles. To investigate the consolidation process, the governing equations for unsaturated composite foundation with T-shaped deep cement mixing piles are firstly derived under the equal strain assumption. Then, semi-analytical solutions for settlement and excess pore pressures are obtained using Laplace transform and transfer matrix methods, and Crump’s method is employed to get analytical solutions in the time domain. The accuracy of the proposed solutions is verified by comparing them with existing ones. Finally, the analysis of the parameters is conducted to explore the consolidation characteristics of unsaturated composite foundation with T-shaped deep cement mixing and deep cement mixing piles. The findings indicate that accounting for the enlarged pile cap leads to a quicker dissipation of excess pore pressures, resulting in a notable reduction in foundation settlement. As the height of the enlarged pile cap and the area replacement ratio increase, the settlement decreases markedly because the enlarged pile cap carries more load.

Sensitivity Analysis of the Factors Affecting the Ground Heave Caused by Jet Grouting

Jet grouted piles are widely used to reduce post-construction settlement of soft clay roadbeds. Nevertheless, it is easy to cause ground heave due to the jet grouted pile. According to the analytical method and numerical method, a sensitivity analysis of the factors affecting ground heave caused by a single jet grouted pile was performed. It is found that the influence of each parameter on ground heave is in the following order: grout pump pressure > embankment load > soil type (including the cohesion, friction angle, and Young’s modulus) > pile diameter > pile length. Considering the effect of the pump pressure on the ground heave is more significant, based on the analytical method of ground heave caused by a single jet grouted pile combined with the solution of small-deflection bending of a circular thin plate, the calculation method for the suggested limit grout pressure for construction under different embankment heights was established. Suggested values of theoretical grout pump pressure were given to prevent ground heave from harming the pavement of operating highways. This study provides some theoretical basis for the subsequent research on the jet grouted pile.

Numerical Simulation of the Load Transfer Mechanism of a Geosynthetic Encased Stone Column Unit Cell under Embankment Loading

Numerical Simulation of the Load Transfer Mechanism of a Geosynthetic Encased Stone Column Unit Cell under Embankment Loading

Comparison of Embankment Properties with Clay Core and Asphaltic Concrete Core

The development of a country is affected by various multifaceted factors, which are likely to generate the highest benefits. For example, developing water resources by constructing embankments to store water and for transportation must consider high resilience, particularly with the current challenges arising from climate change. Another factor that must be considered is the shortage of essential materials for embankment cores, such as clay, which is the primary material for constructing such cores. This study aims to analyze the stability of soil embankments between the change of materials, namely clay and asphaltic concrete, by varying the water level and increasing the embankment load. The result shows that the asphaltic concrete core exhibits a significantly higher stability than the clay core, such as its reduced water seepage and lower deformation. In the worst-case scenario, the asphalt concrete core has a thickness of 0.3 m and a seepage rate of 15.1 × 10−4 m3/day. Comparatively, the seepage rate of the clay core is approximately 10-times lower.

Coupled influence of geosynthetic reinforcement and column configuration on failure dynamics in deep mixed columns under embankment loading

Coupled influence of geosynthetic reinforcement and column configuration on failure dynamics in deep mixed columns under embankment loading

Settlement Calculation of Semi-Rigid Pile Composite Foundation on Ultra-Soft Soil under Embankment Load

Settlement Calculation of Semi-Rigid Pile Composite Foundation on Ultra-Soft Soil under Embankment Load

Study comparison of ground subsidence due to preloading installation of egg tray triangular vertical drains with distance variations on a small laboratory scale

Abstract The approach to infrastructure development is conducted on soft clay soil, which introduces the threat of consolidation-induced subsidence. The construction soil must possess adequate bearing capacity and shear strength to withstand the loads imposed on it throughout the construction process. Soil with low shear strength necessitates reinforcement to enhance its bearing capacity. This study aims to investigate the effects of preloading on the settlement behavior of soft soil. Applying clay-filled test containers, the laboratory implements the method through a small-scale model approach. As preloading, an embankment load is applied to the soil. The supplementary weight was incrementally increased by 1 kg, 2 kg, 4 kg, 8 kg, and 16 kg for five days. The sample experiments that were conducted were EgVD-0, EgVD S-17, and EgVd S-29. Consolidation was observed in the outcomes of the EgVD S-17 and EgVD s-29 investigations, surpassing EgVD-0 by 53.69% and 57.19%, respectively. EgVD S-17 of 3.56 cm and EgVD S-29 of 3.92 cm were present along with an EgVD-0 decrease of 1.65 cm.

A study on the behaviour of soft clay under embankment loading

A study on the behaviour of soft clay under embankment loading

Progressive yielding/softening of soil–cement columns under embankment loading: a case study

Progressive yielding/softening of soil–cement columns under embankment loading: a case study

Analysis of Landslide Handling With Mini Pile Reinforcement Using Plaxis Software on The “X” Toll Road Project

The Semarang-Demak Toll Road faces geotechnical problems due to geological conditions that include hilly areas and basins, with bedrock such as claystone, shale, and lignite that are prone to weakening. A landslide occurred at the Semarang-Demak Toll Road site between Sta. 1+250 and Sta. 2+715, despite various methods of embankment work that were not entirely successful, therefore causing damage. The analysis showed a discrepancy between the theoretical factor of safety and the actual landslide condition, requiring slope reinforcement technology such as mini piles that effectively inhibit soil movement. Mini piles, in the form of reinforced concrete with a length of 7 to 10 meters and a spacing of 2 meters between piles, plus the use of geotextiles, analyzed using the Plaxis 2D program showed an increase in the factor of safety. Although there were slight differences between the reinforcement models, the combination of mini piles and geotextiles proved effective, especially when placed in hard soil layers or over soft soil at a depth of 7 meters from the surface, overcoming the embankment loads at the site.

Numerical study on stability of geosynthetic-encased stone column-supported embankments based on equivalent method

The application of geosynthetic-encased stone column-supported embankments (GESC-supported embankments) has garnered significant attention in geotechnical engineering, with limited investigations into their slope stability. In this paper, an equivalent method was proposed to establish GESC-supported embankment models through three-dimensional finite difference method (3D-FDM). Responses of factor of safety (FS) to arrangement tightness of GESCs (e.g., various column diameters, spacings, and quantities under constant area replacement ratio) and hoop effect of geosynthetic encasements (e.g., various geogrid strengths under different shear strengths of soft soil) were studied. For a given area replacement ratio, FS increased non-linearly with the increasing column quantity or the decreasing ratio of column spacing to diameter at high area replacement ratios. GESCs with smaller diameter and spacing proved to be more effective in improving slope stability, and an optimum ratio of column spacing to diameter was observed for practical use. Besides, FS increased linearly with geogrid strength at low geogrid strength levels, but an extremely lack of the shear strength of soft soils or the column quantity was unfavorable for the application of GESCs. Bending failure was the primary failure feature of GESCs under embankment loading, and the geogrid strength influenced slope stability through the bending capacity of GESCs.

Analytical modeling for the behavior of concrete-cored cement mixing (CCM) pile composite foundation under embankment

The concrete-cored cement mixing (CCM) pile composite foundation is a practical technology for soft soil ground treatment. This paper proposed a theoretical analysis model for the CCM pile composite foundation under embankment in undrained condition which comprehensively considered the interaction between the various components of the CCM pile composite foundation. The working behavior and influencing factors of CCM pile composite foundation under the embankment was also investigated based on the proposed analysis model. The research results showed that: the embankment load was transferred from the outer soil column to the inner soil column. The formation of soil arch effect promoted the concrete core pile to undertake the majority of embankment load, which improved the working behavior of the CCM pile composite foundation under flexible foundation. There was a neutral plane at a certain depth below the ground surface, and the pile shaft above the neutral plane was under negative skin friction, moreover, the vertical stresses of the concrete core pile, cement mixing pile and the soil around the pile all reached the maximum value at the neutral plane.

BiLSTM for Predicting Post-Construction Subsoil Settlement under Embankment: Advancing Sustainable Infrastructure

The load and settlement histories of stage-constructed embankments provide critical insights into long-term surface behavior under embankment loading. However, these data often remain underutilized in predicting post-construction settlement in the absence of geotechnical subsoil characterization. To address this limitation, the current study integrates bidirectional long short-term memory (BiLSTM) into a three-phase framework: data preparation, model construction, and performance evaluation. In the data preparation phase, the feature vector comprises basal pressure, pressure increments, time intervals, and prior settlement values to facilitate a rolling forecast. To manage unevenly spaced data, an Akima spline standardizes the desired time intervals. The model’s efficacy is validated using observational data from two distinct construction case studies, each featuring diverse soil conditions. BiLSTM proves effective in identifying key attributes from load and settlement data during the staged construction process. Compared to traditional curve-fitting methods, the BiLSTM model exhibits superior performance, robustness, and adaptability to varying soil conditions. Additionally, the model demonstrates low sensitivity to the range of post-construction data, allowing for a data collection period reduction—from six months to three—without compromising prediction accuracy (relative error = 0.92%). These advantages not only optimize resource allocation but also contribute to broader sustainability objectives.

Field Tests on Thermal Performance of Bridge Pile Groups under Embankment Load and Cap Constraint Condition

Based on the project of National Highway No. 310 located in Sanmenxia City, China, field tests on the thermal responses of the 2 × 2 pile groups under embankment load in winter condition are carried out. The temperatures and stresses of piles along pile depth under the combined action of embankment load and temperature are measured. The thermal characteristics of the pile body, such as thermal-induced stress, cumulative deformation of the pile top, and heat exchange efficiency per unit area, are analyzed. The feasibility of a new piping method compatible with the segmented reinforcement cage is discussed. A calculation method for heat exchange in a large-diameter energy pile is proposed. The layout of the heat exchange pipe used in this study is feasible, and there is no large stress mutation in the dense and nondense areas. The maximum tensile stress in the middle of the pile body is about 0.4 MPa, which is nearly 22% of the concrete tensile strength value. The settlement of the pile top is about 0.33 mm after seven days of cooling condition, which is about 0.27‰ of the pile diameter.

Research on key technology of cement mixing plie on clay layer with high plasticity index

Cement mixing pile is one of the common methods for road embankment foundation reinforcement, which can improve the bearing capacity, reduce the post-construction settlement caused by embankment loading, and increase the overall stability of embankment. In this paper, through field tests, lab tests and theoretical analysis, the factors affecting the quality of cement mixing piles in deep high plasticity clay soil are analyzed and the results of field tests and lab tests are compared, and finally the key construction parameters and relevant pile strength data in deep marine clay soil area are derived for similar projects.

Extended concentric arches model for piled beam-supported embankments

Geosynthetic-reinforced embankments founded on piled beams have emerged as a new ground modification technique for supporting earth embankments over deep soft subsoil. This paper presents an analytical model for this technique that combines parts of two existing analytical design models. The soil arching behaviour that divides the vertical embankment load into a part that is transferred to the piled beams directly, and the residual load part that rests on the geosynthetic, is described by the 3D part of the Concentric Arches (CA) soil arching model of van Eekelen et al. (2013 and 2015), which was adopted in CUR226:2016. The paper also compares the difference between adopting the 2D or the 3D part of this CA model. The tensioned geosynthetic effect was described by the membrane action equation of Pham (2020b). This equation calculates the geosynthetic strain and includes load–deflection behaviour, adhesion, and friction along the geogrid/soil interface. Two field studies and fully coupled hydromechanical finite element analyses were used to verify the proposed analytical approach and its assumptions. The paper compares the effect of founding geosynthetic-reinforced embankments on piles or piled beams. Finally, a parametric study showed the impact of beam width, center-to-center pile spacing, and geogrid stiffness on load transfer efficiency.

Application of Hardening State Parameter Constitutive Model for Prediction of Overconsolidated Soft Clay Behavior Due to Embankment Loading

This paper investigates the possibility of the application of the HArdening State Parameter (HASP) constitutive model for numerical modelling of overconsolidated soft clay under embankment loading. The HASP constitutive model is a critical state soil model with a combined hardening rule that uses a state parameter to determine the dilatancy of overconsolidated clay. The model overcomes some shortcomings of the Modified Cam Clay (MCC) model in the prediction of overconsolidated clay’s behavior, while preserving the simplicity and the same set of five parameters. The HASP model was implemented in finite element software. In order to verify the applicability of the model in predicting the behavior of soft overconsolidated clay due to embankment loading, two examples reported in the literature are analyzed. The numerical predictions of the HASP model are compared with the field measurements of ground settlements and pore water pressures, and with the MCC model’s predictions. The results indicate that the HASP model predicts the development of the settlements of the overconsolidated soft clay deposits with a high accuracy from an engineering point of view. There are certain deviations from the field measurements in predicting the pore pressure development, which is often observed for other models as well. For the embankment settlement assessment, as important serviceability issue, the HASP model has an advantage over more complex models that require a large number of parameters. Since the parameters of the HASP model are obtained from standard laboratory tests, it can be easily applied for routine geotechnical analyses.

Load Transfer in Geosynthetic-Reinforced Piled Embankments with a Triangular Arrangement of Piles

A geosynthetic-reinforced piled embankment situated along a newly constructed high-speed rail line was fully instrumented and monitored to explore soil arching in an equilateral-triangular arrangement of piles with circular cap configuration. During construction, the settlement and vertical stress on the pile caps and subsurface at ground level and the tensile strain in the geogrid were recorded. A modified analytical arching model is derived from the established concentric arches (CA) model to elucidate the load transfer mechanism, specifically for a triangular array of piles. The general framework assumes that the embankment load, not resting on the subsurface beneath the arches, is transferred outward along the arches and distributed uniformly over the improved ground. Compared to the conventional CA model, the proposed model gives a lower proportion of load carried by piles, more in line with field measurements. Given the friction and adhesion between soil and geosynthetics, a novel quartic equation is applied to characterize the tensioned membrane effect of geosynthetic reinforcement based on Pham’s circular and parabolic models. The stiffness variation of the biaxial geogrid was critically assessed for the triangular pile arrangement, and its implications for the design were revealed. Finally, the pile efficacy and critical arch height were determined from different analytical methods and checked against field observations, demonstrating the potential of the proposed model.