Ma Wei

• Chinese Academy of Sciences

Frozen soil is a common foundation material in cold region engineering. Therefore, the control and prediction of cumulative plastic strain for frozen soil materials are essential for the construction and long-term stability of actual foundation engineering under complex dynamic loadings. To investigate the influence of complex cyclic stress paths o...

Soil properties play a crucial role in the stability of engineering foundations, particularly in cold regions where temperature gradients impact water migration and soil conditions. This study utilized MRI-Cryogenic Soil-Moisture Analyzer (MRI-CSMA) to conduct indoor freeze-thaw experiments on silty clay specimens with varying initial water content...

Preventing and controlling frost heave deformation is critical to artificial freezing construction. Compared to road engineering, the soil experienced complex pressure and constraint conditions during the freezing process. Therefore, this study introduces a new method for measuring the volumetric frost heave coefficient (VFHC) of freezing soil unde...

Cementitious coarse-grained soils are widely used as filling materials in infrastructure projects such as high-speed railway subgrades, earth dams, and highway bases, due to their excellent strength, stiffness, and stability performances. This study conducted unconfined compression tests on fine-grained soils first to investigate the optimal mixing...

The unloading creep deformation and failure of the frozen surrounding rock and soil stratum are common problems in artificial freezing construction. This research aims to experimentally and theoretically study the unloading creep behaviors of frozen soil. A wide range of test conditions, including different pressure history, shear stress paths, and...

A non-frost susceptibility soil is generally not considered to generate significant frost heave. However, recent researches indicate that significant frost heave occurs in coarse fill in engineering, which implies that the frost susceptibility classification based on fine content and particle size may be not reliable. To investigate the frost susce...

Introduction: The embankment in the permafrost zone of the Qinghai–Tibet Railway (QTR) faces the problem of permafrost degradation, especially in the warm and ice-rich permafrost areas. The settlement deformation of the embankment is more serious in these areas. Methods: This study systematically investigates the settlement deformation characterist...

This study discusses a two-year-long field observation of the lateral deformation and ground temperature of an experimental expressway embankment on the Qinghai-Tibet Plateau. The distribution features and evolution process of lateral deformation were obtained and analysed. The results showed that the maximum lateral deformation over 2 years was hi...

Using the triaxial shear or compressive strength as a single index of the resistance of frozen soils to failure does not always meet frozen soil engineering requirements for the comprehensive evaluation of the resistance. In this study, triaxial compression experiments were carried out on undisturbed ice-rich frozen clay samples with various levels...

The rheological behavior of a pile-frozen soil interface can accelerate pile settlement in pile foundation engineering and deteriorate the bearing capacity of the pile in cold regions. This is the core basis for guiding the design of pile engineering and judging the service life of pile foundations. However, it is unclear how the rheological proces...

The thermal state of permafrost in the present and future is fundamental to ecosystem evolution, hydrological processes, carbon release and infrastructure integrity in cold regions. In 2011, we initiated a permafrost monitoring network along the China–Russia crude oil pipeline (CRCOP) route at the eastern flank of the northern Da Xing'anling Mounta...

When considering the dynamic loading processes in the real engineering, such as seismic loading and traffic loading processes, the principal stress direction (PSD) of the of subgrade soil is not always consistent with the vertical direction. As a key factor that determines the deformation behavior of frozen soil, the inclination of PSD is happened...

As a major parameter in the energy balance of the ground surface, temperature represents the level of exchange of energy and moisture between the ground and air. The Qinghai-Tibet Plateau (QTP) has the permafrost region with the highest altitude and the largest area in low-middle latitude of the world. The variation in ground surface temperature ha...

Water supply is one of the dominant factors determining the frost heave, and many researchers have studied the occurrence of frost heaving under the water boundary conditions of no-water supply or no-pressure water supply. Soil freezing is fed by confined groundwater in some cases, however, limited studies have focused on the role of boundary hydra...

The water bodies existing along highways in the high altitude areas of the Qinghai–Tibet Plateau (QTP) will aggravate subgrade settlement and road damage, and affect the long-term stability of road networks. Based on remote sensing and geographic information system (GIS) techniques, this study analyzed the changes in the number and area of water bo...

Freeze–thaw (FT) action is a major cause of rock deterioration in alpine regions. To explore damage evolution of sandstones in cold environment, artificial FT experiments were conducted in the laboratory. Saturated and dry sandstone specimens were subjected to 0, 7, 14, and 28 FT cycles. X-ray computed tomography (CT) images and 3D visualization we...

Since the Little Ice Age and as a consequence of climate warming, many recently deglaciated forefields have become and will continue to evolve into large ice-debris complexes exposed to periglacial processes and environment. Such transitional processes have significant implications for geomorphologic shaping and water supply for the downstream comm...

Frost heave and thaw settlement are primarily caused by water migration. Variations in liquid water and its components during freezing and thawing are crucial variables for investigating water migration. Here, a novel soil layer‐scanning method based on magnetic resonance imaging cryogenic soil‐moisture analysis (MRI‐CSMA) was applied to measure dy...

The thermal state of permafrost in the present and future is fundamental to the ecosystem evolution, hydrological process, carbon release, and infrastructure integrity in cold regions. From 2011, we began to establish a permafrost monitoring network along the China-Russia crude oil pipelines (CRCOPs) route at the eastern flank of the northern Da Xi...

Owing to the limitations of the apparatus, the influence of its principal stress direction on the anisotropic behavior and non-coaxiality of frozen soil has not been fully considered in previous studies. At a temperature of -10°C, a series of hollow cylinder tests for frozen standard sand (FSS) was conducted under different directional angles of ma...

A series of radial splitting tests were conducted on frozen subgrade soil to systematically study the effects of sample size, temperatures, ice contents, loading rates, and prefabricated cracks on the tensile deformation and failure behaviors. Based on extensive experimental results including testing data and photos during the whole loading process...

For the particular engineering-geological conditions and natural environment in permafrost regions, the highway has a high damage ratio during the operation. In warm and ice-rich permafrost regions, highway pavement and embankment have poor serviceability, which threatens driving the vehicle and safe operation. Traditional field surveys on highway...

Crushed rock layers (CRLs), ventilation ducts (VDs) and thermosyphons are air-cooling structures (ACSs) widely used for maintaining the long-term stability of engineered infrastructures in permafrost environments. These ACSs can effectively cool and maintain the permafrost subgrade’s frozen state under climate warming by facilitating heat exchange...

The foundation soil is always subjected to complex stress, including continuous rotation of the principal stress caused by traffic and earthquake loads. To comprehend the dynamic characteristics of frozen clay under complex stress sate, including continuous rotation of the principal stress, this study investigates the effect of temperature on the d...

The contribution of gravel fraction on the maximum shear modulus (G max ), dynamic shear modulus ratio (G/G max ), and damping ratio (λ) of cementitious coarse-grained soils has not been fully understood yet. Large-scale triaxial cyclic tests for geopolymer-stabilized coarse-grained soils (GSCGSs) were conducted with different volumetric block prop...

Geopolymer binders are adjudged as the latest wave of sustainable alkali-activated materials for soil stabilization due to their excellent bonding properties. This study applied metakaolin as a precursor for synthesizing the geopolymer binder by employing the mixture of quicklime and sodium bicarbonate as an alkali activator. The optimal mass mixin...

In this study, the relationship between the computed tomography (CT) number and the density of frozen soil was established on a macro and mesoscopic scale, aimed at overcoming the shortcomings of the mesoscopic damage behavior predicted by previous macroscopic research on frozen soil. In addition, considering the influence of stress level and tempe...

The volume fraction of rock blocks plays a particularly significant role in static/dynamic shear behaviors of soil–rock mixtures (SRM). Large-scale cyclic triaxial tests for SRM with different volumetric block proportions (VBPs) were performed at different confining pressures to investigate the reduction of dynamic shear modulus (G) and the increas...

Across the Qinghai–Tibet Plateau (QTP) there is a narrow engineering corridor with widely distributed slopes called the Qinghai–Tibet Engineering Corridor (QTEC), where a variety of important infrastructures are concentrated. These facilities are transportation routes for people, materials, energy, etc. from inland China to the Tibet Autonomous Reg...

In cold regions, the long-term stability of engineering facilities is unavoidably influenced by the negative temperature, freeze-thaw process, dry-wet process, and dynamic loading conditions induced by earthquakes and traffic loads. In order to investigate the effects of different cyclic stress paths on the evolution of dynamic mechanical propertie...

The physical behaviors of water in the interface are the fundamental to discovering the engineering properties and environmental effects of aqueous porous media (e.g., soils). The pore water pressure (PWP) is a key parameter to characterize the pore water state (PWS) and its phase transition in the micro interface. Traditionally, the water in the i...

The binary mixture of rubber and clean sand has been used as a synthetic porous material characterized by such advantages as light density, strong compressibility and good durability compared to the natural sandy soil. Previous research researches mainly focused on the static properties of this binary mixture. In this paper, the dynamic properties...

Geopolymers are recently regarded as superior sustainable alkali-activated binders (AAB) for soil improvement due to their good bonding properties. In this study, the mixture of sodium silicate (Na2SiO3) and quicklime (CaO) was used as alkali-activator (AA) for preparing AAB employing metakaolin (MK) as a precursor. The unconfined compression tests...

Densely compacted loess foundations of many man-made infrastructures are often exposed to various loads and extreme weathering processes (e.g., drying-wetting cycles), which significantly deteriorate their mechanical properties. Traditional methods applied to characterize soil engineering properties are primarily based on visual inspections, point...

In the Loess Plateau in Northern China, repeated freeze-thaw (FT) cycles deteriorate the strength and structure of loess as a foundation soil, resulting in the instability or failure of supporting structure. Lignosulfonate is an eco-material, utilized as an effective and nontraditional stabilizer to improve the engineering properties of metastable...

Soil-rock mixture (S-RM) is a complex geo-material characterized by competent rock inclusions floating in a weaker soil matrix structure. The mechanical performances of it are significantly controlled by the interaction and properties of rock blocks and the external environment. In this study, experiments on S-RM were conducted through a large-scal...

A series of laboratory experiments, including oedometer tests, direct shear tests, and mercury intrusion porosity (MIP) tests, were conducted to investigate the effects of repeated wetting-drying-freezing-thawing (WDFT) cycles on the mechanic behaviors and pore characteristics of compacted loess. The results of mechanical tests indicate that the WD...

The China-Russia crude oil pipeline (CRCOP) traverses rivers, forests, and mountains over permafrost regions in northeastern China. Water accumulates beside the pipe embankment, which disturbs the hydrothermal balance of permafrost underlying the pipeline. Ground surface flows along the pipeline erode the pipe embankment, which threatens the CRCOP'...

The shear behavior of the frozen soil−structure interface is important for accurately predicting the interface responses of structures adopted in the cold regions. The purpose of this study is to experimentally and theoretically investigate the shear behavior of frozen clay–concrete interface under engineering conditions. A large-scale direct shear...

The crushed rock layers (CRLs) with a satisfied cooling effect on underlying permafrost has been widely used for construction of roadway embankments in cold regions. At present, whether the CRLs can still work as well for an expressway constructed with an integral embankment is still under discussion, it is generally accepted that the expressway wi...

This paper presents multi-stage cyclic loading tests with three confining pressures and eight dynamic stress amplitudes on frozen subgrade soil at the negative temperature − 2 °C to experimentally study accumulative and resilient deformation properties under different cyclic loadings. The coupled effects of the confining pressure and dynamic stress...

There exists a narrow engineering corridor across the Qinghai-Tibet Plateau (QTP) with widely distributed slopes, called the Qinghai-Tibet Engineering Corridor (QTEC), where a variety of important infrastructure is concentrated. These facilities are the transportation routes for people, materials, energy, etc. from mainland China to Tibet. From Gol...

Permafrost is sensitive to both climate warming and engineering disturbance on the Qinghai–Tibet Plateau (QTP). These factors degrade the stability of infrastructure built on permafrost and reduce its service life. To counter these effects, cooling of the subgrade to lower permafrost temperature forms part of the engineering design on the QTP. Proa...

To study long-term strength characteristics under complex stress states, a series of hollow cylinder creep tests were conducted on frozen clay under different stress levels at a temperature of −6 °C. Experimental results showed that the creep characteristics of frozen clay were significantly affected by the mean principal stress and the intermediat...

In permafrost regions, the pipelines buried under the ground are widely used for long-distance transportation of fossil fuel, which contributed to researches focusing on the interaction between such pipelines and surrounding permafrost. In this study, field observations were conducted since 2011 to investigate the thermal interaction between the Ch...

The variations on physical properties and microstructures of soils are essential to explore the freeze-thaw mechanisms. We do some experiments on freeze-thaw test of Qinghai-Tibet silty clay and cryo-Scanning Electron Microscope(cryo-SEM) observing after freeze-thaw test, and monitoring the changes of temperature, pore water pressure and displaceme...

The original landform along the China − Russia Crude Oil Pipeline (CRCOP, line 2) was disturbed during installation of pavement for the pipeline. Forest and vegetation coverage is dense, and runoff develops along the pipe. Since the operation of the CRCOP (line 2) began in 2018, ponding has appeared on both sides of the pipeline. If there is no dra...

Surface water is an important local factor in engineering geological conditions in permafrost regions. In this paper, the impacts of surface water ponding on the long-term thermal and settlement characteristics of an air convection embankment (ACE) were investigated based on 13 years of data records from field observations along the Qinghai-Tibet R...

The chemical stabilization, an important method to stabilize soil foundations, can consolidate the soil particles and raise the strength by chemical reactions. Calcium lignosulfonate, a type of eco-material, was used for loess improvement. Based on numerous experimental results, the engineering properties of stabilized loess such as Atterberg limit...

Linear transportation infrastructure constructed in permafrost zones is severely affected by permafrost degradation and the consequent thaw settlement. Considering the strong heat absorption of wide asphalt pavement, constructing an expressway with an integral embankment or two separated embankments in permafrost zones is under discussion at presen...

In permafrost zones, the ground thermal regime beneath and around foundations is of great importance to long-term stability and integrity of engineering infrastructures. In this study, ground temperatures beneath and around embankments of the Qinghai-Tibet Highway (QTH) and the Qinghai-Tibet Railway (QTR) were observed at two profiles in continuous...

Strong weathering can lead to a weakening of soil structure; such an effect will have a considerable impact on the long-term stability of compacted loess foundations or subgrade engineering. This study used a computed tomography (CT) technique to track the evolution of compacted loess under wetting-drying (WD) cycling, freezing-thawing (FT) cycling...

The long-term serviceability of infrastructures in cold regions is inevitably affected by such dynamic loads in practical works as earthquake loading and vehicle loading. In order to study the deformation characteristics of frozen soil under the seismic loading, namely P-waves and S-waves coupled action, different cyclic stress paths were simulated...

The thermal performance of an experimentally built expressway embankment with a combined cooling measure at Beiluhe Basin in the Qinghai-Tibet Plateau was investigated based on long-term field monitoring. Six-year records of soil temperatures showed that the embankment cooled by a measure combining hollow concrete bricks and ventilation ducts had a...

The permafrost in the Da Xing'anling Mountains Northeastern China has experienced rapid and significant degradation due to climate warming and human activities during the last few decades. In this study, the permafrost degradation and freezing/thawing characteristics of the active layer at Mo'he airport were investigated through a ground temperatur...

In-situ monitoring system is absolutely necessary for a long-distance linear pipeline infrastructure in permafrost regions due to the complicated interaction between buried pipeline and its harsh permafrost environment. To study this complex problem, a comprehensive in-situ monitoring system has been designed and established along the China–Russia...

In this paper, a series of triaxial cyclic loading–unloading (L–U-C), triaxial cyclic loading–unloading–holding (L–U–H-C) and triaxial cyclic stress relaxation tests (L–R-C) were performed for frozen China standard sand (FCSS) under laboratory conditions varying with confining pressure, temperature and holding time. A composite system synchronizing...

The permafrost along the China-Russia Crude Oil Pipeline (CRCOP) is degrading since the pipeline operation in 2011. Heat dissipated from the pipeline, climate warming and anthropogenic activities leads to permafrost warming. The processes of permafrost warming along the CRCOP were studied based on the monitoring of air and soil temperatures, and el...

In this geomorphological research, terrestrial laser scanning (TLS) and a global navigation satellite system (GNSS) were employed to monitor the evolution of surface deformation in two frost mounds located in the Qinghai-Tibet engineering corridor (QTEC). The QTEC is classified as a critical engineering and transportation corridor and is connected...

To study the strength properties of frozen soil in the π-plane, a series of directional shear tests were carried out on frozen clay under five stress Lode angles (θ σ =-30.0°, -16.1°, 0°, 16.1°, and 30.0°) and four mean principal stresses (p=1.0, 3.0, 4.5, and 10.0 MPa) at -6.0 ℃. The results show that the stress-strain behavior of frozen clay perf...

Long-term thermal effects of air convection embankments (ACEs) over 550-km-long permafrost zones along the Qinghai-Tibet railway were analyzed on the basis of 14-year records (2002-2016) of ground temperature. The results showed that, after embankment construction, permafrost tables beneath the ACEs moved upward quickly in the first 3 years and the...

The mechanical properties of frozen soil-concrete interface have a significant impact on lining stability and long-term service ability of water conservation projects and other infrastructures in cold regions. To investigate characteristic and development mechanism of freezing strength of frozen soil-concrete interface, a series of direct shear tes...

To investigate the influence of stress Lode angle on frozen soil, a series of directional shear tests was conducted on artificial frozen clay at three temperatures (–6, –10, and –15 °C) and five stress Lode angles (θσ = –30°, –16.1°, 0°, 16.1°, and 30°) using a hollow cylindrical apparatus. An elliptical function was proposed according to the stren...

In this paper, the dry cement was mixed with warm and ice-rich permafrost to improve its mechanical and physical properties. The changes of temperature of improved soil with different cement dosage were measured by in-situ test. Then, the temperature field of the improved soil in-situ test was calculated by mathematical model of heat conduction and...

The Qinghai-Tibet Engineering Corridor (QTEC) in China may reflect the changes in the alpine ecosystem of the Qinghai–Tibet Plateau (QTP) that are driven by global climate change combined with intensive human activities. We used the normalized difference vegetation index (NDVI) as an indicator of alpine vegetation activity and the permafrost active...