Compressive Deformation Characteristics Research Articles

Compressive Deformation Characteristics of Sintered Loess after Being Saturated with Water

Compressive Deformation Characteristics of Sintered Loess after Being Saturated with Water

Study on compaction characteristics and mechanical model of dry crushing filling material under lateral confinement condition

The compaction characteristics and bearing capacity of dry filling materials in goaf have a significant influence on stope control and surface stability. Through acoustic emission monitoring and mechanical model analysis, a series of confined compression tests were conducted on crushed waste with varying particle sizes and Talbot coefficients. The deformation, fragmentation, and acoustic emission characteristics under corresponding working conditions were determined. The results indicate that the stress–strain curves of crushed stone with different particle sizes and Talbot coefficients exhibit similar nonlinear behavior during confined compression. However, the strain response varies with changing stress levels. By analyzing the slope change rate of the stress–strain curve, the lateral uniaxial compression process of waste rock can be divided into three deformation stages: rapid compression, stable crushing, and slow compaction. The compressive deformation characteristics of gravel differ based on particle size and Talbot coefficient. Specimens with a higher Talbot coefficient demonstrate stronger compressive resistance and weaker deformation resistance during initial compaction loading. Notably, the internal pressure structure strength is influenced by factors such as maximum particle size D, grading coefficient n, and particle size distribution continuity, rather than solely by the proportion of large particles. The evolution of acoustic emission signals and energy-time curve during waste rock confined axial compression synchronizes with the compaction process. Overall, compaction plays a critical role in maintaining the stability of goaf in dry crushed waste filling.

Compression deformation characteristics and mechanisms study of multi‐layer structures with triply periodic minimal surfaces

AbstractTriply periodic minimal surfaces (TPMS) and honeycomb structures are typical representatives of porous structures. In this paper, multi‐layer structures based on the combination of P‐surfaces and honeycomb structures are fabricated and the compression deformation characteristics are investigated based on quasi‐static compression tests and finite element simulation. The results show that the established finite element model can better simulate the deformation and damage modes of the multi‐layer structure, and the multi‐layer structure exhibits layer‐by‐layer deformation and sequential compression collapse in the deformation process. The tensile stress is crucial in the deformation and damage process of the P‐structure layer. The honeycomb structure layers show two different deformation modes: the inverted bell‐shaped “upward extrusion” and the bell‐shaped “downward extrusion.”

Microcrack monitoring and fracture evolution of coal and rock using integrated acoustic emission and digital image correlation techniques.

The mechanical properties of a coal-rock body were examined through uniaxial compression tests, and the rupture process of the coal-rock body was monitored in real time using a combined acoustic emission (AE) monitoring system and a digital image correlation (DIC) full-field strain measurement system. From a comparison of the mechanical properties of coal and sandstone, clear differences are apparent regarding the uniaxial compressive strength, deformation characteristics, and damage mode; the brittle failure characteristics of the coal samples are also more evident. The change in AE energy reflects the accumulation and release of elastic energy during the rupture process, and the evolution of AE localization points under different stress levels can effectively reflect rupture propagation. Further, the DIC full-field strain measurement method can quantitatively monitor the evolution of the displacement and strain fields at the marking point and surface simultaneously, thereby overcoming the limitations of traditional empirical and qualitative rupture processes. During monitoring, the AE focuses on the internal rupture of the specimen and the DIC focuses on the surface deformation. These complement each other and reflect the rupture process more comprehensively.

A novel cylindrical mechanical metamaterial: Design, fabrication, and compressive properties

Mechanical metamaterials exhibit fascinating deformation characteristics and exceptional mechanical properties due to their distinctive unit cell structure and the repetitive development of these units. This research presents the design of a novel cylindrical metamaterial featuring a concave hexagonal structure. This design incorporates an auxetic structure within the outer circular tube in order to enhance radial shrinkage and improve bearing capacity and stability by leveraging the negative Poisson's ratio effect. The specimens were fabricated using 3D printing technology, and their mechanical properties and uniaxial compression deformation characteristics were subsequently investigated through experiments. Additionally, the accuracy of the finite element model was verified by comparing the simulated predictions with the experimental results. The specimens differ in terms of their internal and external structures. The external structures vary based on the combination of single cells and interlayers, resulting in three distinct types. The internal structures differ based on the angle of inward depression. The mechanical properties and deformation characteristics of specimens composed of different internal and external structures were analyzed, revealing that the cylindrical structure can possess adjustable stiffness, high stability, and compressive capacity.

Hot compression deformation characteristics of TiBw/Ti65 composites for high-temperature application

Hot compression deformation characteristics of TiBw/Ti65 composites for high-temperature application

Utilisation of waste rock backfill materials in deep gobs for mitigating mining-induced water inrush risks: compression deformation and seepage characteristics

Utilisation of waste rock backfill materials in deep gobs for mitigating mining-induced water inrush risks: compression deformation and seepage characteristics

The Characteristics of the Deformation of a Feeding Roller with Double V-Wings Honeycomb under Driven Modes with Different Rotation Rates and Axial Compressions

In this work, the roller-shaped double V-wing honeycomb (DVWH) structure was used as the object, which was designed for forest harvesting machines. The deformation characteristics of its rotation under a specific compression were studied during the feeding process for the steel feeding roller used in the traditional combined harvesting machine for trees, which is prone to damaging the wood. The compression rate (10%–15%) and rotational speed (100 mm/s–320 mm/s) were used to analyze the relationship between compression rate, rotational speed, and deformation characteristics. The deformation characteristics, characterized by equivalent stress, radial displacement sensitivity, and energy absorption efficiency, were analyzed. The results show that the deformation characteristics of the roller-shaped DVWH structure under driven mode were more sensitive to compression rate and less sensitive to changes in rotational speed. There was a positive correlation between the equivalent stress of the node and the compression rate. The peak equivalent stress of the outermost node at 10% and 15% compression rates were 111.9 MPa and 230.9 MPa. There was a negative correlation between radial displacement–compression sensitivity and compression rate, and a decrease in radial displacement–compression sensitivity from 10% to 15% compression rate at different nodes ranges from 5% to 22%. The feed performance efficiency (EF) grew from 8.3% to 12.7% for a 1% increase in compression rate.

Performance Study on Laterite Road Base Stabilised with Emulsions Incorporating Biochar

This study explores the utilisation of biochar as an innovative and sustainable additive to emulsions for stabilising laterite road base material in pavements, with the environmental benefit of sequestering atmospheric carbon and stable form storing. A diverse range of design mixtures for the treated road base material with the proposed biochar–emulsion binder was developed for experimental validation and subsequent steps encompassed an array of laboratory tests to scrutinise the engineering attributes of the mixtures. The tests were selected to assess various properties such as unconfined compressive strength, tensile strength, resilient modulus, flexural modulus, fatigue life, and deformation characteristics. To gain practical insights from real-world conditions, two field trials were also conducted to evaluate the performance of the stabilised road base. The findings revealed that a design mix incorporating 5% biochar and 6% emulsion delivered an average unconfined compressive strength (UCS) of 1.5 MPa, which adheres to the standard UCS range for cemented lightly bound base course material. The optimal ratio of biochar to emulsion was identified as 1:1.6, which delivered a higher resilient modulus value than did the minimum stipulated by the literature for average daily traffic in the first year of design. As the temperature rose, the stabilised laterite base exhibited a reduction in its flexural modulus; however, it demonstrated minimal susceptibility to fluctuations in frequency. The deformation observed in the wheel-tracking tests for mixtures of the optimum biochar-to-emulsion ratio was less than 1 mm, which is remarkably lower than the maximum requirement outlined in the literature (i.e., 15 mm). Furthermore, visual inspection post-testing detected minimal cracking. These findings indicate that the integration of biochar and emulsion in the construction of road pavements is a promising technique that could contribute to carbon sequestration and climate change mitigation without sacrificing pavement performance. The successful field trials provided further evidence of the feasibility of this novel technique.

Study on unconfined compressive strength and deformation characteristics of chlorine saline soil

The distribution of saline soil is wide and the area is large in China. The saline soil in different regions shows their own characteristics. The saline soil of single salt is configured by adding different contents of NaCl to the loess in Xi'an. The effects of chlorine content and water content on soil strength and volume change in a large water content range was studied, and the change mechanism was analyzed by scanning electron microscopy. The results show that the strength of chloride saline soil increases with the decrease of water content. The moisture content of 12% is the critical point of strength change of chloride saline soil. When the moisture content is greater than 12%, the strength of soil decreases with the increase of salt content. When the water content is less than 12%, the strength of saline soil is 3% NaCl content > 1% NaCl content > 5% NaCl content > 0% NaCl content. The volume change of the sample consists of three parts: elastic deformation during sample pressing, volume shrinkage during water loss and salt expansion. In the absence of NaCl and 1% NaCl content, the sample was in the state of shrinkage during the loading process, in which with the decrease of moisture content shrinkage rate slowed down. The volume change rate of 3% and 5% NaCl showed an inflection point from negative to positive when the water content was 15%. When the water content is less than 12%, the saline soil with 3% NaCl content has the characteristics of high strength and unobvious salt expansion. The method of adding 3% NaCl to loess in Xi 'an area can be used to simulate the cement between soil particles, which provides a reference for artificially preparing structural soil. According to the microstructure analysis, the higher the salt content of saline soil, the smaller the soil pores, and the contact form of soil particles gradually develops from the point contact between soil particles to the salt-wrapped structure.

Formulation of PG-FA-L composite modifier for repairing expansive soil based on the statistical mixed design method

The generation of large amounts of solid waste has led to exploration of solid waste-modified expansive soils; however, the effect of a single solid waste-modified expansive soil is not ideal. This study proposes a composite modification of expansive soils using a PG-FA-L system. Statistical analysis showed that the properties of the cured soil were significantly improved. PG and FA increased soil strength after a certain threshold, and L increased it at all stages. The presence of PG accelerated the volcanic ash reaction. Both PG and FA have a small effect on the swelling of the soil, whereas lime improves it significantly, but has a negative effect after a certain threshold. The 28-day unconfined compressive strength and deformation characteristics were used to derive the relevant regions for roadbed fill requirements and determine the optimum dosage.

Study on Uniaxial Compression Deformation and Fracture Development Characteristics of Weak Interlayer Coal–Rock Combination

With increases in mining depth and intensity, disasters such as stress concentration, slab failure, and coal body dynamic outbursts at the coal–rock interface have become more serious. Therefore, it is important to analyze the stress–strain behavior of coal–rock combinations to explore the deterioration process and failure characteristics of coal–rock combinations. In this study, we used field survey, theoretical analysis, and numerical simulation methods to explore the microstructure characteristics of the coal–rock interface and the influence of interlayer thickness on the composite body. The results show that with the increase in interlayer thickness, the compressive strength of the composite body gradually decreases. This reduction is mainly due to the interlayer dividing the coal sample, resulting in a decrease in the equivalent elastic modulus of the composite body, weakening of the overall integrity, and a decrease in carrying capacity. In addition, the failure mode and mechanical properties of the coal–rock combination are influenced by the interlayer position. Different “soft layer” positions can lead to changes in the overall carrying and failure modes of the coal–rock composite. The position of the interlayer also has a significant influence on the failure mode and fracture propagation of the composite body. This study provides an important theoretical reference for the control of coal–rock deformation and instability and regional rock mass modification in underground engineering.

Super plasticity of bulk metallic glasses at room temperature: A friction self-locking state

This study examines the compressive deformation and fracture characteristics of Fe74Mo6P13C7 bulk metallic glasses (BMGs) with aspect ratios ranging from 1.0 to 2.5. The compressive plastic strain of BMGs exhibits a consistent upward trend as the aspect ratio decreases. As the aspect ratio decreases, the influence of the surrounding friction becomes increasingly pronounced. The finding was made that the exceptional ability of BMGs to exhibit super plasticity at ambient temperature is attributed to the phenomenon of friction self-locking occurring within the shear planes. The deformation behavior of brittle BMGs is significantly influenced by the applied stress conditions. However, it is worth noting that even brittle BMGs can display ductile characteristics when subjected to multiaxial constraints. This finding is not only essential for comprehending the deformation and fracture of amorphous materials, but it can also serve as a valuable reference for rock mass control, structural stability, earthquake mitigation, and disaster reduction engineering.

Effects of particle size on compressive deformation characteristics of broken rock mass in gangue rib of automatically formed gob-side entry retaining

In automatically formed gob-side entry retaining techniques, one side of the retaining roadway consists of the gangue rib structure. The stability of the gangue rib and the movement of the overlying strata are significantly influenced by the compressive deformation characteristics of crushed stones. In this research, a large gangue rib similar compression device was designed to perform compression tests on gravel of different particle sizes. Additionally, a novel three-dimensional gravel compression simulation method was introduced, which involved the construction of irregular crushable clusters to simulate the compression and re-crushing process of gravel. The findings indicate a positive correlation between particle size and compression ratio under increasing stress. The gangue exhibits a prominent skeletal load-bearing effect, characterized by repeated processes of load-bearing, crushing, filling, and load-bearing. During compression, the porosity of the gravel decreases exponentially, and larger particle sizes result in higher degrees of fragmentation, showing a tendency of layered compaction.

Effect of Organic Matter Components on the Mechanical Properties of Cemented Soil.

The organic matter in soft clay tends to affect the properties of cement-stabilized soil. The influence degree of different organic matter varies. In this paper, the influence weights and mechanism of the main organic matter components fulvic acid and humic acid on the mechanical properties of cemented soil were investigated. Impacts of FA/HA (fulvic acid/humic acid) values and curing time on the unconfined compressive strength, deformation characteristics, and microstructure of cemented soil were explored through the unconfined compressive strength test and electrical resistivity test. The results show that with the increase of FA/HA, the unconfined compressive strength of cemented soil gradually decreased and the plastic properties enhanced. The increase in curing time changed the stress-strain relationship of cemented soil, and some specimens showed brittle damage. The initial resistivity and structural property parameters of cemented soil gradually decreased with the increasing FA/HA value and increased with the increase of curing time. It revealed the influence law of FA/HA and curing time change on the microstructure of cemented soil. Based on the experimental results, the quantitative relationship equations between FA/HA and curing time and unconfined compressive strength, failure strain, deformation modulus, and resistivity were established.

Study of Constitutive Models of Reconstituted Clay with High Initial Water Content

The compression and shear behavior of reconstituted clay are closely related to the initial water content of the reconstituted soil. It is difficult to obtain the compression and shear test data of clay with a high initial water content. This study aims to propose a model to predict the compression deformation and strength characteristics of reconstituted clay prepared with any initial water content using less data. Based on the concept of the disturbed state, this paper establishes a mathematical model that can simulate the compression and triaxial shear characteristics of reconstituted clay with different initial water contents. This model uses three compression curves of reconstituted clay with different initial water contents to calibrate the model parameters, and can predict the compression deformation characteristics of reconstituted clay prepared with any initial water content. The model can simulate the consolidated undrained shear behavior of clay reconstituted with different initial water contents. Comparing the measured data shows that the model is in good agreement with the measured compression curve and the triaxial stress–strain curve. The error of the predicted pore ratio and test pore ratio before yield is within 5%, and the error of the predicted pore ratio and test pore ratio after yield is within 10%. The stress–strain relationship of clay hardening with different water contents can be captured. The model can provide a preliminary prediction for the mechanical properties of clay with a high initial water content.

Compressive Deformation Characteristics of Crushed Sandstone Based on Multiple Experimental Factors

Compressive Deformation Characteristics of Crushed Sandstone Based on Multiple Experimental Factors

Discrete element numerical analysis for bearing characteristics of coral sand foundation considering particle breakage

Owing to the construction demands of island and reef engineering, studying the bearing and deformation characteristics of coral sand foundations is significant. This study used the discrete element method to simulate the plate loading test of coral sand foundations based on the actual experiments of coral sand foundations. The particle breakage of coral sand was considered by the fragment replacement method, and the influence of relative compactness on the particle breakage behaviour and compression deformation characteristics of coral sand foundations was analysed. The results show that the compression process of the coral sand foundation undergoes three stages: compaction, shear deformation, and failure. The bearing capacity, deformation modulus, and particle breakage rate of the coral sand foundation increase with the increasing relative compactness, but the growth trends are different significantly at different relative compactness. The numerical analysis indicates when the relative compactness of the foundation increases, the contact force and coordination number would increase, the relative displacement would decrease, causing more particle breakage. This microscopic phenomenon explains why the increasing trend of bearing capacity and deformation modulus of the foundation decreases with the increasing relative compactness.

Compressive Deformation Characteristics of Nb<sub>2</sub>Co<sub>7</sub> as Crystalline Mille-Feuille Structured Material

The uniaxial compressive deformation characteristics of single-phase Nb2Co7 were investigated by an electron backscatter diffraction analysis focused on microstructural evolution and kink formation in order to determine whether this monoclinic intermetallic phase is a novel crystalline “mille-feuille” structured (MFS) material. During uniaxial compressive deformation, Nb2Co7 does not behave brittle but shows high plasticity. In some microstructure regions, kink-like structures are observed, showing no delamination. In kink-free regions, the frequency of boundaries with rotation angles of 60°, 120°, and 180°, which correspond to changes in the monoclinic stacking vector of Nb2Co7 layers between adjacent close-packed (CP) layers, increases significantly after the compression test. The interfaces in the kink-like structures are low-angle boundaries with rotation axes within basal (001) planes. The rotation angles and axes of interfaces in the kink-like structures take various values, suggesting that the origin of the kink-like structures is not twinning, but in fact, these structures are a result of deformation kinking. Deformation of single-phase Nb2Co7 is considered to occur due to dislocation glide on basal (001) planes and kink formation, which is regarded as playing an indispensable role in the plasticity of Nb2Co7 during compression. It can therefore be concluded that Nb2Co7 is a novel crystalline MFS material.

Rate-dependent ratcheting characteristics of high density polyethylene subjected to cyclic pulsating compression

Monotonic and pulsating cyclic compression tests were performed systematically based on high density polyethylene (HDPE). The compressive creep behaviors were further implemented to compare with the ratcheting deformation under the same peak stress level. Monotonic compression experiments reveal that HDPE shows obvious four-stage characteristics which are sensitive to temperature, but independent of the stress rate when the temperature is greater than 80 °C. Interestingly, the strain range during the stage III always starts at 7.4% and ends at 62.6% under various temperatures and stress rates. Moreover, the compressive ratcheting behavior of HDPE significantly depends on temperature T, peak stress σp, stress rate σ˙, stress amplitude Δσ and stress ratio R, especially when T ≥ 80 °C, σp ≥15 MPa, σ˙ ≤0.1 MPa/s and R ≥ 0.8. Additionally, decreasing the stress rate or increasing the temperature will decrease the compressive modulus of HDPE. An approximate linear relationship between the creep strain rate and the ratcheting strain rate under different temperatures and stress ratios was observed. The compressive deformation characteristics of HDPE were compared with that of some other gasket materials, a universal phenomenon is found that the compressive ratcheting evolution with time can be characterized by creep approximately under the same loading peak stress, stress rate and temperature for various gasket materials when the stress ratio is greater than zero, which indicates that the ratcheting deformation for gaskets under cyclic loads may be estimated by the corresponding static creep strain in practical engineering.