Expansive soils may naturally exist or used as a compacted material and its behavior should be examined under conditions simulating real field conditions. In field, there are two possible loading/wetting conditions may be experienced by expansive soils. One is that it may be flooded after finishing of structure construction, while the other possible condition is that where flood come first and followed

Buried culverts are important components of highway infrastructure. Most large culverts are built decades ago from corrugated metal or reinforced concrete materials and now have reached their design life. A variety of renewal techniques can be utilized to enhance load carrying capacity of the existing deteriorated culverts and extend their design life. Spray applied pipe lining (SAPL) is a trenchless

This paper investigates the effects of cover ratio and soil strength parameters (cohesion and friction angle) on the failure mechanisms of cohesive soils overlying trench voids using trapdoor technique. Adaptive finite element limit analyses (AFELA) were conducted to study the failure mechanisms of trapdoors covered with soils of different thicknesses, cohesions and friction angles. It was found that

The application of reclaimed asphalt pavement (RAP) has become a common practice in road construction as a substitute to natural aggregate. The significance of RAP amount on the resilient modulus behavior, shear strength and hydraulic conductivity characteristics of unbound granular base materials were investigated in this research. RAP was blended with crushed aggregate by different percentages ranging

The goal of this paper is the use of a fly ash with high unburned carbon which generally has lower demand in the market because, according to ASTM C618, it cannot be used in Portland cement concrete. Alkali-activated cements (AACs) based on this industrial by-product were prepared using granulated blast furnace slag (GBFS) and lime (L) as calcium sources. The AACs were used for A-4 type soil improvement

Permeable pavements have been widely used as an effective means to improve hydrological characteristics and the ecology of the urban environment. This study aims to investigate the response of fully permeable pavement (FPP) subjected to dynamic loading under dry and saturated conditions. A full-scale test track topped with polyurethane bound permeable material (PUPM) was built to obtain the stress

Approximately 110,000 km of granular roadways exist in the 183,500 km road network in the State of Iowa, and operation and maintenance of these roadways costs roughly US$270 million annually. The major maintenance costs of these roads are aggregate cost and hauling costs from the quarries to the sites. Accordingly, acquiring a cost-effective, high performance, and environmentally sustainable surface

The dynamic performance of a bridge-tunnel transition section with a deep buried pile-plank structure (DBPPS) for short transitions was studied. Field tests were performed, analyzing accelerations, velocities and displacements in the track and subgrade. Based on the field test results, the influences of the train types, driving direction and running speed on the dynamic response in the transition zone

Degradation of railway ballast aggregate is ensued from breakage of single particle as well as from abrasion of angular corners. The present study evaluates the change in morphological characteristics as well as particle size distribution of ballast aggregate degraded under applied impact loads to further illuminate the degradation mechanism of particles. The utilized drop-weight impact loading apparatus

This study investigates the effects of grass age on hydraulic properties of coarse-grained volcanic soil, namely: Komaoka soil. The soil-water characteristic curve (SWCC), unsaturated coefficient of permeability, outflow, runoff, and the variations in volumetric water content/matric suction under different rainfall intensities varying from 15, 30, 60, to 120 mm/h are measured by carrying out column

This paper presents novel findings regarding the use of alkali-activated slag for the development of road applications and, more particularly, how the interactions that occur between the binder and the organic matter originally present in the soil can strongly affect its reactivity in the process of stabilization and solidification. The study uses mechanical performances and macroscopic characterization

The subgrade layer often represents the weakest component of a pavement system, and can significantly affect pavement response and performance under loading. Adequate characterization of subgrade properties is critical to the design and construction of long-lasting, economical pavement systems. The Mechanistic-Empirical (M-E) pavement design protocol implemented through AASHTOWare Pavement ME Design

As an important part of national security, railway safety is also an eternal theme in the development and maintenance of railways. In this study, to explore the establishment of high-speed railway geosubstructure safety indices and maintenance technology, worldwide typical design or maintenance standards and codes are summarized and compared, and theoerical analyses and testings are carried out to

Centrifuge testing of both single pile and multiple long-pile groups was conducted using saturated silt soil to investigate the distinct response of piles under adjacent surcharge loads. The behavior of the piles in the soil was also determined using 3-dimensional (3D) numerical analysis. Through the verified model parameters, pile responses were explored from different surcharge loads and distances

Rockfalls on transport infrastructures are a serious hazard to users and many resources are invested in rock slope maintenance, stabilization, and protective measures. In volcanic territories, the risk of rock instabilities and rockfalls is very high due to the rugged natural slopes and origin of rock masses. With the aim of determining the influence of the geometric and material-related properties

The vibration of a coupled pavement and unsaturated ground system subjected to a moving traffic load is semi-analytically studied. The pavement is modeled as an infinite Kirchhoff plate, and the unsaturated ground is presented by an unsaturated poroelastic half-space. The traffic load of a truck is simplified as a combination of 10 rectangular loads. The governing equations of the pavement-ground system

Shrinkage cracking of cementitiously stabilized layers (CSL) causes distresses in a pavement structure and decreases the pavement’s service life. Thus it is important to develop methods that can characterize properties of cementitiously stabilized materials (CSM) that lead to shrinkage cracking. Limited test methods are available to characterize the shrinkage behaviour of CSM. Shrinkage of CSM consists

This paper presents a laboratory study on alleviating the deformation and degradation (breakage) of ballast subjected to impact loads using geogrids and rubber mats. A series of drop hammer impact tests are carried out to determine how well the geogrid, under-ballast mat (UBM) or under-sleeper pad (USP) can attenuate impact loads and mitigate ballast degradation. Geogrids to be placed at different

Although being widely used as the quality control for field compaction, neither the standard nor modified Proctor tests match the compaction effort of existing field compaction machineries commonly used today. More importantly, these methods are incapable of identifying the compactability of soil materials other than maximum dry density and optimum moisture content. With the widespread application

The determination of the shear strength of coarse-grained soils in standard shear devices is a challenging task due to the presence of large grains. Three approaches could be used to reduce the grain size of the tested specimen. This study aimed to determine whether the shear strength of a coarse-grained soil with fines (particles smaller than 0.08 mm) can be estimated by the parallel gradation approach

The objective of this study was to determine the effectiveness of commercially available polymer soil stabilizers in expansive soil swell reduction relative to quicklime and Class C fly ash. A survey of state departments of transportation within the Mountain-Plains region of the USA (Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming) was conducted to define the state-of-practice in expansive

Soil-reinforcement interface friction is an important geotechnical engineering parameter that needs to be assessed in achieving a safe and cost-effective design. In this study, the effect of mean particle size (D50), type, and surface properties of reinforcements on shear behavior of soil-reinforcement interface were evaluated using direct shear test. Three types of sands with different D50 and similar

The aim of this work is to study the effectiveness of the enzyme-mediated calcium carbonate (CaCO3) precipitation methodology when applied to the confined and unconfined behavior of a silty sand. Based on the analysis of the results of UCS and oedometer tests carried out with non-stabilized and biocemented specimens, the effects of the curing time and the concentration of the biogrout solution (urease

This paper presents a series of experimental studies for evaluating the effects of closed-system freeze–thaw (FT) cycles on the hydro-mechanical behaviours of two subgrade soils (a low plastic lean clay, SS and a lean clay with higher plasticity, HC). Investigated hydro-mechanical behaviours include the soil–water characteristic curve (SWCC) obtained from the filter paper method, resilient modulus

Ballast degradation has a strong effect on railway track performance (including accumulative deformation, ballast resistance, and drainage). The main objective of this research is to determine the evolution of roundness during ballast degradation and investigate the mechanical properties of real ballast shape at different abrasion stages. To this end, the Los Angeles (LA) abrasion test is conducted

This paper presents a practical method for identifying the fundamental design parameters of a multilayered earth structure in ballastless tracks at an operational speed of 400 km/h. The properties of subgrade materials and layer thickness are determined based on vehicle–track coupled dynamic numerical analysis and integrated empirical models incorporating a threshold cyclic strain approach. The principle

In permafrost regions, the construction of embankment leads to the permafrost degradation, further affecting the embankment stability. Considering wider bituminous pavement and higher technical standard for expressway than ordinary highway, the heat and deformation behaviors of the separated expressway are investigated through a full-scale field experimental expressway embankment in the Qinghai-Tibet

Shrinkage cracking is one of the primary distresses found in cementitiously stabilized layers (CSL) of pavements. Shrinkage can cause cracking on the surface layer due to the bond between the surface layer and the CSL. Shrnkage of CSL includes autogenous shrinkage due to hydration, drying shrinkage due to loss of moisture, and thermal shrinkage due to low temperature contraction. The current methodology

While backward erosion piping (BEP) and slope instability failure mechanisms have been investigated independently, they are not analyzed concurrently despite that the response of levees embankments to the BEP may likely impact the stability of the slope, especially if levees were to fail. This study presents a framework towards interfacing soil instability and BEP simulation with the goal of producing

This paper proposes an environmental assessment approach consistent with sustainable development principles in the design of underground structures. A literature review highlighted the methods applicable at the project construction stage for buildings or road infrastructure that may specifically be intended for the underground. An underground assessment was developed and implemented for the urban case

Ballast contamination due to intrusion of fine particles from subgrade is characterized as a conventional source of ballast fouling. To diminish this phenomenon, sub-ballast layer is incorporated between the subgrade soil and the ballast course of railway track structure. Present study investigates the influence of subgrade type, compaction level and gradation of sub-ballast material and particle size

Various applications of biopolymer-based soil treatment (BPST) in geotechnical engineering have been implemented in recent years, including dust control, soil strengthening and erosion control. Despite BPST methods can ensure the effectiveness of engineering while meeting environmental protection requirements, BPST technology requires further validation in terms of site applicability, durability, and

Traditional pavements in urban areas are often impervious, resulting in augmented surface run-off during rainfalls, thereby leading to flash floods and pollution of waterways. In contrast, permeable pavements allow percolation of water through their surface layers, thus alleviating the harmful impacts associated with traditional pavements. This study reports on the mechanical performance of a large-scale

In volcanic terrains and in particular island regions, the aggregates come from the mechanical crushing of lava rocks and pyroclastic deposits. This study offers an experimental database of the geomechanical characteristics of different volcanic rock lithotypes and the aggregates obtained from these rocks. For this purpose, 971 aggregate samples and 643 rock samples of 11 different common volcanic

The disintegration of red-bed soft rock is closely associated with a series of geological disasters. However, research on the evolution of the disintegration breakage has not yet been sufficiently executed. To compensate for this insufficiency, slake durability tests are carried out by three widely used experimental methods to explore the disintegration of red-bed soft rock. Then, based on the logistic

Structure surface normally owns highly directional properties caused by the properties of the material and the manufacturing process. Proper understanding of soil–structure interface behavior must recognize the structure surface’s highly directional properties and take into consideration its interactions with particulate material. To investigate the mechanical behavior of granular soil–structure interface

In-depth field instrumentation was undertaken on a section of a large diameter (660 mm) cast iron water pipe in Sydney, Australia to monitor the performance of a field pipeline under internal and external loads. This paper elaborates the instrumentation details and procedures adopted to capture various infield data to support the condition assessment of buried ageing pipelines under operational conditions

Soil improvement by incorporating different reinforcement materials has been one of the most popular fields of study in geotechnical engineering since it can provide the engineers with a practical and relatively easy solution when dealing with various construction projects. Despite numerous studies carried out on the static behavior of reinforced soils, the dynamic characteristics of these mixtures

Morphological analysis is an important prerequisite step for studying the mechanical properties of unbound granular geomaterials through both laboratory experiments and numerical simulations. In this study, two typical geomaterials, e.g., ballast and cobbles, are sampled for study. First, a systematic framework is established to acquire two-dimensional (2D) particle outline and three-dimensional (3D)

To quantitatively investigate the morphological features of railway ballast, a new statistical index, Curvature Index (CI), was presented. With a set of 584 digitized railway ballast particles obtained through 3D scanning, the statistical distribution functions of CI and existing global shape indices (i.e., long axis, middle axis, short axis and sphericity index) were obtained. Then, based on Proper

Deep foundations are very important elements in the routine design of railways and bridges when the loads applied due to these important structures are higher than the bearing capacity of the soil. However, the methods currently available to calculate the bearing capacity of driven piles embedded in clay have been developed based on empirical factors derived from limited tests. Hence, further assessment

A volume-shear coupling mechanism is imperative for developing high-speed railways in very cold regions. A series of consolidated drained static triaxial experiments were carried out to investigate the effect of freeze-thaw (F-T) cycles on the stress-strain features of coarse-grained materials (CGM) typically used at the bottom layer of subgrade for high-speed rail tracks in China. Mathematical expressions

The Optimal Recycling of Reclaimed Asphalts in low-traffic Pavements (ORRAP) project concerns a cold recycling of 100% Reclaimed Asphalt Pavement (RAP) without binder addition, in base and subbase layers of low-traffic pavements. The mastic coating of aggregates induces a viscoelastic behaviour and changes the resilient modulus with frequency and temperature. This modulus is obtained with repeated

A new prefabricated vertical drain (PVD) with wings has been proposed, and its behaviour has been investigated using laboratory model tests and finite element analysis (FEA). The new PVD uses wings that are aligned perpendicularly to the surface of the PVD and is thus named WPVD. The wings increase the contact area of a WPVD with soil and serve as a horizontal drainage channel, and this can be more

Differential settlements can affect transition zones between bridges and road embankments in countries where very compressible soft soil layers are widespread in the subsoil. The related damage makes these locations the most maintenance-prone locations, resulting in high direct and indirect costs for the road owner and the road users as well. Accordingly, approaches capable of analysing current conditions

The aim of this research is to study the effect of temperature and stress levels on the permanent strain of blends of two types of recycled waste materials, namely recycled concrete aggregate (RCA) and reclaimed asphalt pavement (RAP). RAP was mixed with RCA in different percentages of up to 80% by dry mass. A three-stage repeated load triaxial (RLT) testing procedure was employed for evaluation of

The disposal of waste tyres in a landfill has been outlawed in Europe since 2000, with some exceptions being made for construction works. Since then, tyre-derived products have been widely used in road applications. One of these applications is in tyre bales, comprising 100–140 car vehicle tyres compressed into a lightweight block and secured by galvanised steel tie wires running around the length

The piled-raft foundation in soft clay ground for high-speed trains has suffered serious settlement due to cyclic train loading in recent years. It was urgent to implement countermeasures to improve the natural ground. In this research, firstly, a ground treatment technique was proposed to reduce permanent train-induced deformation. Permeation grouting was injected into the bearing strata of group

The aim of this study is to understand the local mechanisms related to creep behavior of a typical clay under triaxial loading. The investigation concerns both normally consolidated and overconsolidated specimens of remolded kaolin clay. The macroscopic results showed that both dilatancy and contractancy could occur during creep depending mainly on the clay behavior prior to the creep test. The magnitude

The increased popularity of using a deep cement mixing (DCM) column as a ground improvement element in soft ground has brought about the need to identify how the targeted strength and stiffness values defined in guidelines can be achieved considering the water content and the incorporated cementitious materials. This paper addresses this important aspect by studying the strength and stiffness variations

Ballast/fines mixture is often found in railway substructure and the overall behaviour of tracks is strongly dependent on the mechanical behaviour of this mixture. Since directly testing such mixture with large grains is limited with common laboratory equipment, the consideration of a model material at smaller size is advisable. Parallel gradation method is widely used for this purpose. This study

This paper presents the results of using rigorous modeling artificial neural network and genetic algorithm to examine the proper stabilization of very weak subgrade soils at high moisture contents. The experimental database was performed in Louisiana transportation research center for four types of soft soil, 125 samples data were prepared and used in development ANN and genetic algorithm models. For

Continuous heave was observed in a High-Speed Railway subgrade section, which caused severe track irregularity and damage to the concrete structure. After exploring the current relevant research and the construction information of the heave section, this paper addresses the causes and characteristics of the deleterious heave. Displacement and temperature sensors were installed in field to investigate

Soil properties play important role to the metro tunnel settlement induced by traffic load of metro operation. Numerical studies on this topic are still rare due to the lack of accurate dynamic constitutive models of clay. In this study, a new critical state based bounding surface plasticity model for natural structured clays is first developed. It is able to consider the initial and induced anisotropy

Based on long-term, continuously monitored data of an expressway, this paper analyzes the influence of pavement types on thermal stability of block-stone embankments with variations of temperature, heat flux, heat budget change, freeze-thaw cycles, permafrost table, and thawing plate area. Results show that closer to the ground, the annual average temperature of the block-stone embankment with asphalt

Previous studies showed that the permanent strain of interlayer soil in the French conventional railway substructure is highly dependent on the volumetric coarse grain content fv (volumetric ratio of coarse grain to total sample). This study developed a fatigue model allowing the effects of coarse grain content fv, stress state and number of loading cycles N on permanent strain to be accounted for

Ballast layer is a part of railway foundation that its behavior is affected by the properties of constituent particles. The shape of the particles, which affects ballast behavior, is an important characteristic that is represented by angularity and sphericity indexes. In this study, the macro- and micro-mechanical shear behaviors of railway ballast are investigated by using Discrete Element Method

This paper aims to demonstrate the anisotropic behaviour of railway ballast via true-triaxial tests. To do so, a novel, large-scale, true-triaxial testing apparatus (GeoTT) is designed and constructed. It consists of six hydraulic actuators, designed to apply a distributed stress to large granular cubic test specimens with dimensions: 500 mm × 500 m × 500 mm. To show the capability of the new facility

High sulfate expansive soils present special challenges during stabilization. Traditional stabilizers such as lime and cement which are rich in calcium are ineffective in controlling shrink/swell behavior of these soils due to formation of the expansive mineral, ettringite. In this study, two geopolymers synthesized from aluminosilicate sources, fly ash and metakaolin, were investigated to determine