Catastrophic Instability Research Articles

Investigation on instability mechanism and control of abandoned roadways in coal pillars recovery face: A case study

The abandoned roadways (ARs) in front of the longwall face catastrophic instability will seriously hamper mining progress, which is a complicated process related to the stress environment, the roadway section, and the mechanical properties of the surrounding rock. The cusp catastrophe theory is employed to establish a state identification model for the irregular coal pillar-roof system (CPRS) formed by the ARs and re-mining entries. To begin, the state discrimination equation (Δp) for the gradual CPRS is derived, and the critical value at which the system transitions into an unstable state under quasi-static conditions is determined. The results indicated that when 16.49 m ≤ L ≤ 22.63 m (L denotes the equivalent span of the intersection roof) and 0 < Re ≤ 2.61 m (Re denotes the width of the elastic zone within the triangular coal pillar), the triangular CPRS is inherently unstable. Similarly, for trapezoidal CPRS configurations where the length Lm (the span of the right-angled trapezoid roof in the propulsion direction) varies from 4.0 to 12.60 m, the system is unstable as well. Subsequently, the model was further enhanced by accounting for the impact of the Pc (advance stress increment load), where a critical criterion for the catastrophic instability of the CPRS was proposed, which represented the external energy required to transition the CPRS from an unstable state to catastrophic instability in different mining stages. After that, the stability degree of the irregular coal pillar was categorized, and a coupling zoning control technology was applied to CPR operations. Field monitoring results demonstrated the effectiveness of the zoning control technology, providing valuable guidance for similar mining practices.

Damage evolution of coal with a strong bursting liability and 3D measurement method for elastic deformation energy distribution

When coal with a strong bursting liability is disturbed by a load, catastrophic instability disasters and rockbursts can easily occur. Loaded coal with a strong bursting liability undergoes complex damage evolution and failure behavior due to the intricate interplay among loads, gangue, fractures, and the coal matrix. Intuitively quantifying and characterizing the complex discontinuous structural features, deformation fields, and energy fields within coal is the foundation for the scientific analysis and prevention of disaster mechanisms caused by rockbursts. Therefore, studying the distribution and evolutionary processes of deformation fields and energy fields caused by the evolution of discontinuous structures within coal is highly important for the prevention and control of coal mine rockburst disasters and the protection of coal mine safety during mining operations. In this study, a series of X-ray computed tomography (X-CT) tests were conducted on coal specimens with varying gangue contents under uniaxial compressive loading. The X-CT images clearly illustrated the internal damage evolution of coal with a strong bursting liability, revealing fracture propagation, shear bands, and localized failure under varying loading conditions. Image segmentation was employed to quantitatively analyze the development of damage in coal with a strong bursting liability, revealing the influence patterns of gangue content on the prepeak deformation localization and strength of coal. Additionally, using digital volume correlation, the 3D volumetric displacement and strain of loaded impact-prone coal were determined based on the changes in natural speckle images. The nonuniform distribution of strain was mainly caused by the nonuniform distribution of gangue and pore fractures at the microscopic scale, which explains the localized deformation in coal materials. Importantly, this study provides new full-field strain tensor data and a novel method for measuring the elastic deformation energy of the 3D deformation and cracking processes of loaded coal.

Human AAA+ATPase FIGNL1 suppresses RAD51-mediated ultra-fine bridge formation.

RAD51 filament is crucial for the homology-dependent repair of DNA double-strand breaks and stalled DNA replication fork protection. Positive and negative regulators control RAD51 filament assembly and disassembly. RAD51 is vital for genome integrity but excessive accumulation of RAD51 on chromatin causes genome instability and growth defects. However, the detailed mechanism underlying RAD51 disassembly by negative regulators and the physiological consequence of abnormal RAD51 persistence remain largely unknown. Here, we report the role of the human AAA+ATPase FIGNL1 in suppressing a novel type of RAD51-mediated genome instability. FIGNL1 knockout human cells were defective in RAD51 dissociation after replication fork restart and accumulated ultra-fine chromosome bridges (UFBs), whose formation depends on RAD51 rather than replication fork stalling. FIGNL1 suppresses homologous recombination intermediate-like UFBs generated between sister chromatids at genomic loci with repeated sequences such as telomeres and centromeres. These data suggest that RAD51 persistence per se induces the formation of unresolved linkage between sister chromatids resulting in catastrophic genome instability. FIGNL1 facilitates post-replicative disassembly of RAD51 filament to suppress abnormal recombination intermediates and UFBs. These findings implicate FIGNL1 as a key factor required for active RAD51 removal after processing of stalled replication forks, which is essential to maintain genome stability.

A Dynamically Stable Sulfide Electrolyte Architecture for High-Performance All-Solid-State Lithium Metal Batteries.

All-solid-state batteries employing sulfide solid electrolyte and Li metal anode are promising because of their high safety and energy densities. However, the interface between Li metal and sulfides suffers from catastrophic instability which stems the practical use. Here, a dynamically stable sulfide electrolyte architecture to construct the hierarchy of interface stability is reported. By rationally designing the multilayer structures of sulfide electrolytes, the dynamic decomposing-alloying process from MS4 (M = Ge or Sn) unit in sulfide interlayer can significantly prohibit Li dendrite penetration is revealed. The abundance of highly electronic insulating decompositions, such as Li2S, at the sulfide interlayer interface helps to well constrain the dynamic decomposition process and preserve the long-term polarization stability is also highlighted. By using Li6PS5Cl||Li10SnP2S12||Li6PS5Cl electrolyte architecture, Li metal anode shows an unprecedented critical current density over 3mAcm-2 and achieves the steady over-potential for ≈900 hours. Based upon the merits, the Li||LiNi0.8Co0.1Mn0.1O2 battery delivers a remarkable 75.3% retention even after 600 cycles at 1 C (1C-0.95mAcm-2) under a low stack pressure of 15MPa.

Unraveling Novel Mechanisms for Targeting the Intra-S-Phase Checkpoint in p53-Mutated Acute Myeloid Leukemia

Tp53 mutated acute myeloid leukemia (AML) is a highly challenging subtype to treat due to its aggressive nature and resistance to standard therapies. Even in cases where initial responses to conventional treatments occur, residual minor clonal populations harboring p53 mutations place patients at a higher risk of relapse and lower overall survival rates. Thus, innovative treatment strategies are essential to tackle the challenges of p53 mutated AML and enhance patient outcomes. Although it plays a substantial role in G1/S and G2/M checkpoints, p53's significance in the intra-S-phase checkpoint is limited. This checkpoint is vital in detecting replication defects and its disruption leads to catastrophic genome instability, massive DNA breakage, and cell death. We endeavored to target this pathway by employing a non-ATP cell cycle inhibitor, LBS-007, that blocks the kinase activity of CDC7 that is responsible for phosphorylating MCM2 prior to DNA replication initiation. Thus, we hypothesized that inhibition of CDC7 can disrupt DNA synthesis, leading to genomic instability and potentially p53-independent cell death. Initially, we explored LBS-007 as a single agent in a p53 deleted (17p-) AML cell line and two AML lines with hot-spot p53 mutation (R175H or R248Q). LBS-007 showed significant effectiveness in all three cases with altered p53 status and with GI 50 values comparable to those observed in wild-type p53 AML cells (62 nM, 40 nM, and 59 nM versus 133 nM). To further enhance its therapeutic impact, we investigated combinations with other DNA replication inhibitors. When used sequentially with LBS-007, hydroxyurea provided a robust response yielding GI 50's between 1 and 3 nM for LBS-007, effectively blocking DNA replication origins (LBS-007) and inducing fork stalls (HU). Surprisingly, the combination of LBS-007 and an ATR inhibitor, Ceralasertib, had a paradoxical effect, suggesting the effectiveness of LBS-007 requires intra-S-phase checkpoint activation. To determine the underlying molecular mechanisms, we conducted RPPA analyses on p53 defective AML cells treated with LBS-007. We observed significant upregulation of apoptotic proteins and pathways when used as a single agent (Figure 1A). However, in combination with hydroxyurea, activation of DNA damage sensors and intra-S-phase checkpoint proteins were overrepresented (Figure 1B). The observed effectiveness of LBS-007 in driving robust p53-independent apoptosis and cell cycle checkpoints indicates its potential as a powerful new agent to treat p53-mutated AML. To discover synergistic combinations that enhance the efficacy of LBS-007, we utilized venetoclax, a BCL2 inhibitor that facilitates apoptosis. The inclusion of venetoclax significantly increased the efficacy of LBS-007, resulting in combinatorial GI 50's below 10 nM in both p53 mutated and p53 deleted AML. Most impressively, the combination of LBS-007 and venetoclax was exponentially enhanced when used in conjunction with ceralasertib (4.8 pM). Collectively, these results provide compelling evidence that combining CDC7 inhibition and venetoclax with a potential ATR inhibitor will have a profound impact on treatment of p53 altered AML (Figure 2). We are now evaluating the efficacy of these combinations using xenograft transplant models. To this end, cohorts of mice transplanted with AML cell lines harboring either wild-type or mutated p53 will be treated with strategies identified through our in vitro and RPPA analyses. Further studies will address the cooperation between mutations common to AML and p53 alterations using defined PDX models. Our results identify a unique and potentially efficacious strategy to treat one of the most difficult to treat subtypes of AML. These findings will provide the rationale for potential clinical trials using CDC7 inhibition in p53 mutated or R/R AML.

Total of time variation diminishing principle for conservation laws

We introduce a new principle for devising numerical schemes for conservation laws in one and multiple dimensions. The new formulation is based on the Total of Time Variation (TOTV) defined as the volume integral of the magnitude of the time derivative. For the one-dimensional scalar advection equation with a constant velocity, TOTV and the usual total variation (TV) are the same except for a constant factor. For non-linear equations and/or in multiple dimensions, TV and TOTV are different. We show that TOTV is a conserved quantity for one- and multi-dimensional scalar conservation laws with a non-linear flux function that can depend on the spatial coordinates as well. We call a numerical scheme that ensures that the discrete form of TOTV is not increasing in time a Total of Time Variation Diminishing (TOTVD) method. A TOTVD scheme is stable against catastrophic instabilities that would lead to uncontrolled growth of the time derivative. We show that the first order upwind scheme with a finite time step satisfying the usual CFL condition is TOTVD for all equations that satisfy the TOTVD property analytically. We demonstrate the difference between TV and TOTV with numerical tests.

PULL-DOWN INSTABILITY OF THE QUADRATIC NONLINEAR OSCILLATORS

A nonlinear vibration system, over a span of convincing periodic motion, might break out abruptly a catastrophic instability, but the lack of a theoretical tool has obscured the prediction of the outbreak. This paper deploys the amplitude-frequency formulation for nonlinear oscillators to reveal the critically important mechanism of the pseudo-periodic motion, and finds the quadratic nonlinear force contributes to the pull-down phenomenon in each cycle of the periodic motion, when the force reaches a threshold value, the pull-down instability occurs. A criterion for prediction of the pull-down instability is proposed and verified numerically.

Critical slowing down phenomenon for predicting the failure of solid rocks and cement mortar materials: Insight from acoustic emission multiparameters

Failure precursors with clear physicomechanical connotations are of great significance in predicting catastrophic instability in major constructions and rock engineering. Here, we conducted uniaxial compression tests on natural solid rocks and cement mortar materials and obtained their acoustic emission (AE) activity characteristics during the damage evolution to explore the feasibility of AE parameters in characterizing the failure precursory characteristics of building materials. Based on the critical slowing down theory, the curves of the variance and autocorrelation coefficient for AE multiparameters were analyzed. The results show that the sudden increase in the variance and autocorrelation coefficient of AE multiparameters can be used as primary and secondary criteria, respectively, for the identification of failure precursors. Their physicomechanical connotations were clear, characterizing the dominance of shear failure modes and the onset of accelerated fracture. The discriminability of failure precursors characterized by the critical slowing down of the AE energy rate, RA value, and RA/AF value was higher than that characterized by the critical slowing down of the cumulative AE ring count and peak frequency. Moreover, we found that the building materials with high brittleness, strength, and heterogeneity present a more significant critical slowing down phenomenon. In the view of early-warning time, the occurrence of precursory features identified by autocorrelation coefficient was earlier than the occurrence of precursory features identified by variance.

Experimental research on the instability characteristics of the overlying strata structure that characterizes shallow interval goaf mining

Abstract Here, we analyze the instability characteristics of the overlying strata structure that characterize shallow-depth seams under insufficient goaf in Yushenfu mining area. To simulate the No. 20107 longwall interval working face situated in Nanliang Coal Mine, physical simulation, an acoustic emission (AE) monitoring system, a stress acquisition system and a total station were used. The results indicate that during interval goaf formation, which is correlated with mining, the immediate roof collapses, and the main roof strata remains stable. Gradually, the stress that acts on the temporary coal pillar (TCP) gradually exhibits the ‘uniform increase–accelerated increase catastrophe instability’ change characteristics. Due to the concentrated load of the overlying strata, the bearing capacity of the TCP gradually deteriorates until the catastrophic instability occurs, and the unstable roof strata forms a ‘W-shaped voussoir beam’ structure. The research results provide evidence for the strata control that is associated with shallow-seam mining.

Numerical modeling of the failure process of the heterogeneous karst rock mass using the DDA–SPH method

The sanding process caused by karstification in dolomite creates a special sandy dolomite stratum, where the frequent catastrophic instability of the surrounding rock occurred during tunnel construction. In this study, the micro-origin and macro-performance of the sandy dolomite stratum are first discussed. Then, a numerical model based on the coupling method between the discontinuous deformation analysis and smoothed particle hydrodynamics is proposed to depict the heterogeneous dolomite formation with different sanding degrees. Following, the mechanical behaviors of the heterogeneous dolomite samples under uniaxial compression are studied after calibrating the numerical parameters with the two single materials sampled from the tunnel site respectively. Further, the instability disasters of the dolomite surrounding rock with different sanding degrees are reproduced, and the failure behaviors of tunnels are explained with respect to the stress distribution and plastic zone. The obtained results show that the rotation and dislocation of the remained dolomite block contribute to the unsmooth stress–strain curve and deterioration in uniaxial compressive strength. However, the block serves as the skeleton in the transmission of field stress in underground space, which improves the stability of the formation.

Effects of Sweep on the Flutter of Wraparound Fins

In the field of missile and rocket design, efficiency is a crucial aspect considering factors such as weight, storage, stealth, and cost. Wraparound fins (WAFs) have been used for many years to control the trajectory of missiles and rockets because of their compactness and effectiveness. However, WAFs are structurally more flexible than other types of fins, which may negatively impact their dynamic behavior and aeroelastic response. This can cause catastrophic instabilities, such as flutter. To mitigate these challenges, it is essential to consider both aerodynamic and structural models of WAFs during the design process. In this study, the flutter velocity and frequency of WAFs were investigated in relation to different structural design configurations and sweep angles, in order to understand and improve the aeroelastic performance of swept WAFs.

Disruption of CDK7 signaling leads to catastrophic chromosomal instability coupled with a loss of condensin-mediated chromatin compaction

Chromatin organization is highly dynamic and modulates DNA replication, transcription, and chromosome segregation. Condensin is essential for chromosome assembly during mitosis and meiosis, as well as maintenance of chromosome structure during interphase. While it is well established that sustained condensin expression is necessary to ensure chromosome stability, the mechanisms that control its expression are not yet known. Herein, we report that disruption of cyclin-dependent kinase 7 (CDK7), the core catalytic subunit of CDK-activating kinase, leads to reduced transcription of several condensin subunits, including structural maintenance of chromosomes 2 (SMC2). Live and static microscopy revealed that inhibiting CDK7 signaling prolongs mitosis and induces chromatin bridge formation, DNA double-strand breaks, and abnormal nuclear features, all of which are indicative of mitotic catastrophe and chromosome instability. Affirming the importance of condensin regulation by CDK7, genetic suppression of the expression of SMC2, a core subunit of this complex, phenocopies CDK7 inhibition. Moreover, analysis of genome-wide chromatin conformation using Hi-C revealed that sustained activity of CDK7 is necessary to maintain chromatin sublooping, a function that is ascribed to condensin. Notably, the regulation of condensin subunit gene expression is independent of superenhancers. Together, these studies reveal a new role for CDK7 in sustaining chromatin configuration by ensuring the expression of condensin genes, including SMC2.

Symmetry restoration in the vicinity of neutron stars with a nonminimal coupling

We propose a new model of scalarized neutron stars (NSs) realized by a self-interacting scalar field ϕ nonminimally coupled to the Ricci scalar R of the form F(ϕ)R. The scalar field has a self-interacting potential and sits at its vacuum expectation value ϕv far away from the source. Inside the NS, the dominance of a positive nonminimal coupling over a negative mass squared of the potential leads to a symmetry restoration with the central field value ϕc close to 0. This allows the existence of scalarized NS solutions connecting ϕv with ϕc whose difference is significant, whereas the field is located in the vicinity of ϕ=ϕv for weak gravitational stars. The Arnowitt-Deser-Misner mass and radius of NSs as well as the gravitational force around the NS surface can receive sizable corrections from the scalar hair, while satisfying local gravity constraints in the Solar system. Unlike the original scenario of spontaneous scalarization induced by a negative nonminimal coupling, the catastrophic instability of cosmological solutions can be avoided. We also study the cosmological dynamics from the inflationary epoch to today and show that the scalar field ϕ finally approaches the asymptotic value ϕv without spoiling a successful cosmological evolution. After ϕ starts to oscillate about the potential minimum, the same field can also be the source for cold dark matter.

Fracture response and damage evolution features of coal considering the effect of creep damage under dynamic loading

When coal under creep deterioration is disturbed by impact load, it is easy to induce catastrophic instability disasters, rock burst. To analysis the fracture and failure evolution of coal considering the effect of creep damage under dynamic loading, the SHPB simulation experiment under different creep and impact stress was carried out, and the mesoscopic mechanism, damage degree, force chain fabric and energy evolution were analyzed. The results show that coal mesoscopic particles move inward along the axial direction and outward along the minimum principal stress, and there are most tensile shear cracks near the incident end face, the most shear cracks along axial direction, the main tension cracks along radial direction. Crack damage shows an S-shaped trend with time, increasing significantly during the pre-peak stress stage and growing linearly with dynamic stress at the peak stage. Fragment damage shows a J-shaped trend with time, rising significantly after the peak and increasing linearly with the creep stress at the peak stress. The strong fabric mainly transmits stress waves, and changes from axial compression to radial expansion at the peak stress. The aggregation distribution and strength enhancement of strong chains destroy the coal mesoscopic bond and cause macroscopic cracks expanding and penetrating. During the creep and pre-peak stage, there is most external energy changed into strain energy. At peak stress, sliding and dashpot energy grows significantly under high creep stress, and the strain energy ratio decreases with dynamic stress. The study can theoretically describe mesoscopic coal failure evolution and reveal deep mining disasters process.

Non-trivial dynamics in a model of glial membrane voltage driven by open potassium pores

Despite the molecular evidence that a nearly linear steady-state current-voltage relationship in mammalian astrocytes reflects a total current resulting from more than one differentially regulated K+ conductance, detailed ordinary differential equation (ODE) models of membrane voltage Vm are still lacking. Various experimental results reporting altered rectification of the major Kir currents in glia, dominated by Kir4.1, have motivated us to develop a detailed model of Vm dynamics incorporating the weaker potassium K2P-TREK1 current in addition to Kir4.1, and study the stability of the resting state Vr. The main question is whether, with the loss of monotonicity in glial I-V curve resulting from altered Kir rectification, the nominal resting state Vr remains stable, and the cell retains the trivial, potassium electrode behavior with Vm after EK. The minimal two-dimensional model of Vm near Vr showed that an N-shape deformed Kir I-V curve induces multistability of Vm in a model that incorporates K2P activation kinetics, and nonspecific K+ leak currents. More specifically, an asymmetrical, nonlinear decrease of outward Kir4.1 conductance, turning the channels into inward rectifiers, introduces instability of Vr. That happens through a robust bifurcation giving birth to a second, more depolarized stable resting state Vdr > −10 mV. Realistic recordings from electrographic seizures were used to perturb the model. Simulations of the model perturbed by constant current through gap junctions and seizure-like discharges as local field potentials led to depolarization and switching of Vm between the two stable states, in a downstate-upstate manner. In the event of prolonged depolarizations near Vdr, such catastrophic instability would affect all aspects of the glial function, from metabolic support to membrane transport, and practically all neuromodulatory roles assigned to glia.

Timing of integration into the chromosome is critical for the fitness of an integrative and conjugative element and its bacterial host.

Integrative and conjugative elements (ICEs) are major contributors to genome plasticity in bacteria. ICEs reside integrated in the chromosome of a host bacterium and are passively propagated during chromosome replication and cell division. When activated, ICEs excise from the chromosome and may be transferred through the ICE-encoded conjugation machinery into a recipient cell. Integration into the chromosome of the new host generates a stable transconjugant. Although integration into the chromosome of a new host is critical for the stable acquisition of ICEs, few studies have directly investigated the molecular events that occur in recipient cells during generation of a stable transconjugant. We found that integration of ICEBs1, an ICE of Bacillus subtilis, occurred several generations after initial transfer to a new host. Premature integration in new hosts led to cell death and hence decreased fitness of the ICE and transconjugants. Host lethality due to premature integration was caused by rolling circle replication that initiated in the integrated ICEBs1 and extended into the host chromosome, resulting in catastrophic genome instability. Our results demonstrate that the timing of integration of an ICE is linked to cessation of autonomous replication of the ICE, and that perturbing this linkage leads to a decrease in ICE and host fitness due to a loss of viability of transconjugants. Linking integration to cessation of autonomous replication appears to be a conserved regulatory scheme for mobile genetic elements that both replicate and integrate into the chromosome of their host.

Research on cemented artificial pillars to replace protective inter-block coal pillars and stope failure laws

Replacing protective inter-block coal pillars (PICPs) with cemented artificial pillars is proposed here to address low coal recovery rates. The use of cemented artificial pillars also reduces resource waste when PICPs are used in the short-wall block mining (SBM) process. A coal mine test area in northern Shaanxi, China, was employed as the study site. Artificial pillar replacement techniques were developed based on the layout characteristics of a typical SBM workface. High-strength cemented backfill materials for artificial pillars were manufactured using innovative material ratio testing, and the optimum ratios for backfill materials are discussed. A cusp catastrophe model of an artificial pillar was then developed and used to deduce the conditions and critical widths necessary to generate catastrophic instability of an artificial pillar. This theoretical analysis was validated using FLAC3D simulations. Using the test site conditions, the simulations revealed that when an artificial pillar had a width of 14 m, the destruction of the pillar and associated stope was gradual and would not cause catastrophic instability. Field monitoring performed at the test site verified the theoretical analysis and numerical simulation results, confirming that it was feasible to replace PICPs with cemented artificial pillars.

Universe before Big Bang

The ghost condensation of the early universe in a pre-big bang phase has been presented in this paper through duration of a non-singular bounce. The undergoing universe contracts and passes smoothly in an expanding universe via a post-big bang phase. Initially developing and then taming any ghost like instabilities, the Null Energy Condition (NEC) is explicitly violated through the curvature mechanism of an adiabatic perturbed metric. The vacuum state of the ongoing phase is stabilized via a Lagrangian that in essence stabilizes the vacuum state under the higher order derivatives. The violation of the NEC regards a catastrophic vacuum instability, which re-emerges with a correction valid at small energies and momenta, below the UV-cut-off scale that, could potentially be problematic if one tries to construct a UV-completed theory of this Ekpyrotic model. The scale-invariant curvature perturbation, that arises and is sourced out of the scale-invariant entropy perturbations sourced by 2-Ekpyrotic scalar fields, that, in contrast, becomes constant on the super-horizon limits, due to the non-singular nature of the background geometry. Apart, from the ghost condensates, this theory addresses the new Ekpyrotic theory which in order becomes a distinguishable alternative to inflation theory for the birth of the universe. As per the recent WMAP data, the Ekpyrotic model has a spectral red tilt that shows the bounced scalar potential falling through a negative phase shift during the matter-fluid fluctuations in the hot big bang phase.

A flow model in bulk metallic glasses

Based on the microscopic mechanisms applicable to bulk metallic glasses (BMGs), such as the free-volume theory and fracture theory of brittle solids, a constitutive equation for the crack-like propagation velocity of shear bands in BMGs is deduced, νSBcl=ν0a0exp(−ES/kT). Furthermore, a flow model of monolithic BMGs is successfully established, logνSB=log(ν0a0)+logeES/(kTl)−logeES/(kT). The model explains clearly the fundamental deformation of BMGs at the temperature far below the liquidus temperature, i.e., the mechanism of serrated flows. Not only does the model accurately predict the transition between serrated and non-serrated flows, but the Arrhenius equation and activation energy received by the current model for most BMGs are consistent with the experimental results. The current study paves a way to plastically process BMGs, avoiding catastrophic plasticity instability.

Triaxial creep damage–catastrophe instability characteristics and a nonlinear constitutive model of gas-bearing coal

Triaxial creep damage–catastrophe instability characteristics and a nonlinear constitutive model of gas-bearing coal