Slip Behavior Research Articles

Effective Bulk Rheology of a Two‐Phase Subduction Shear Zone: Insights From Micromechanics‐Based Modeling and Implications for Subduction Interface Slow Slip Events

AbstractSubduction interfaces exhibit various slip styles, including slow slip events (SSEs). We use a micromechanics‐based approach to calculate the effective rheology of a shear zone containing ellipsoidal amphibolite clasts deforming by dislocation creep within an interconnected linear‐viscous phyllosilicate‐dominated matrix. Frictional failure occurs if local stress exceeds Mohr‐Coulomb yield strength. At moderate fluid overpressure, mixed‐frictional‐viscous behavior emerges at 350–560C, consistent with a broad zone of mixed fault slip behavior without requiring extreme fluid overpressures. Increasing stress in this transition zone promotes local frictional failure and raises bulk strain rate. If, however, the bulk strain rate increases by more than one order of magnitude, system‐wide frictional sliding becomes preferable. This strain rate increase is insufficient to explain the slip rates observed in geophysically detectable SSEs. Therefore, viscous matrix flow as modeled here cannot explain SSEs without either invoking dynamic weakening within a frictional‐viscous flow or a mechanism switch to dominantly frictional sliding.

Experimental and analytical investigations on bond–slip behavior of steel reinforcement in UHPFRC considering yielding

AbstractThe bond behavior between ultra‐high‐performance fibre‐reinforced concrete (UHPFRC) and steel rebars plays an important role in the load‐bearing capacity and serviceability of structural members. A suitable bond–slip model is essential for predicting the load resistance and deformation capacity of members, after cracking of the UHPFRC. This paper studies the bond strength between ribbed steel bars and the surrounding UHPFRC before and after yielding of the steel reinforcement. To determine the corresponding bond–slip relationship, pull‐out tests, with varying embedment lengths of the reinforcement, namely 2 times and 10 times the rebar diameter, and diameter of reinforcing bars ranging from 10 mm to 16 mm were conducted. The bond stress, strain and slip along the embedment length of the steel rebars were measured by strain gauges and displacement transducers. Based on the test data, a bond stress–slip model was derived before (elastic stage) and after (inelastic stage) yielding of the reinforcement. The slip at the yield point is suggested through theoretical equations. The post‐yield bond–slip model is based on yield bond stress and frictional bond stress. The two‐part model was validated through iterative procedures and is able to predict the applied force, bond stress and strain distribution along the reinforcing bar. A comparison between the test data and analytical results demonstrates a good predictive capacity on the bond behavior of reinforcement in UHPFRC both before and after yielding of the reinforcement.

Experimental study on the characteristics of fault stick–slip behavior under different normal stresses

Experimental study on the characteristics of fault stick–slip behavior under different normal stresses

Ascertaining the deformation accommodation of a novel Ti-652 alloy by tracking the evolution of slip traces and lattice strain

The exploration of slip modes in metallic materials during deformation has been long suffered from either insufficient statistical accuracy of slip trace analysis or limited spatial resolution by X-ray diffraction. In this work, a combination of slip trace analysis based on in-situ Electron Backscatter Diffraction (EBSD) and lattice strain analysis supported by in-situ Synchrotron Radiation High-Energy X-ray Diffraction (SR-HEXRD) was employed to determine the deformation accommodation mechanisms of a new developed Ti-6Al-5Mo-2Sn-0.3Si-0.5 V (Ti-652) alloy. Different from conventional cases, it was surprisingly found that pyramidal (101̅1)α slip is easier to be initiated than prismatic (101̅0)α within α grains, resulting in the dominant slip modes evolving from prismatic <a> to pyramidal I <c+a>. In addition, in-situ EBSD results show that slip can transfer across grain boundary (GB) in counterintuitive situations with low geometric compatibility factor m′ of 0.5, or with GB misorientations in the range of θ≥24.5°, which are contractive to the slip transfer criterion in hcp structures. Further detailed crystallographic analysis revealed that specific slip transferred across GBs with 24.5°≤θ≤60° because of high Schmid Factor (SF) values, while with θ>60° slip transfer occurred by activating another slip systems. The accumulation of multi-mode slip dislocations induced by deformation accommodation with different phases was suggested to promote the formation of sub-GBs within the deformed parent grain. These findings provide insights of the slip behaviors and property tailoring in Ti alloys.

Heterogeneous mineralogical composition and fault behaviour: A systematic study in ternary fault rock compositions

The heterogeneous mineralogical compositions of fault gouges, formed during fault evolution, influence frictional properties and slip behaviour. While the influence of individual mineral phases on friction has been extensively studied, the impact of varying systematically mineral phases in gouge mixtures on macroscopic frictional behaviour remains unclear. Thus, we performed 34 frictional experiments on fault gouges composed of three representative mineral phases: muscovite (platy phyllosilicate), quartz (granular silicate) and calcite (granular carbonate), known for their markedly distinct frictional properties. Using a biaxial rock deformation apparatus (BRAVA), we performed tests on fault gouges with grain sizes <125 μm under normal stresses of 50–100 MPa, at room temperature and water-saturated conditions. Our data indicate that the mineralogical composition of fault gouges significantly affects frictional strength, healing, and stability with a non-trivial pattern. Increasing the muscovite content leads to a decrease in frictional strength, from 0.62 for pure calcite and 0.56 for pure quartz to 0.33 of pure muscovite, along with reduced frictional healing and a velocity-strengthening behaviour. This weakening is promoted by a transition from localized deformation along discrete shear planes in granular-rich fault gouges to distributed deformation within the entire gouge layer with increasing muscovite content. At fixed muscovite content, frictional properties depend on the dominant granular phase. Calcite-dominated mixtures exhibit more marked frictional weakening rather than quartz-dominated ones, suggesting a non-linear mixing law between friction coefficient and muscovite content. This different trend is likely due to favourable conditions for fluid-assisted pressure-solution of calcite and foliation development, unlike quartz. When only the granular phases are mixed, we observe complex behaviour with the indentation of quartz into calcite, resulting in higher values of healing rates than those of pure end-member mixtures.Our findings provide robust insights into microphysical processes strongly dependent on the complex mineralogical compositions usually observed along natural faults.

Entropy optimization of MHD second-grade nanofluid thermal transmission along stretched sheet with variable density and thermal-concentration slip effects

The goal of present investigation is to explore the influence of exponential variable density and entropy optimization on second-grade nanofluid heating efficiency and mass-concentration transmission along extended surface using external magnetic-field and temperature-concentration slip effects. To enhance the motion of nanoparticles and thermal efficiency, the influence of exponential form of temperature-based density on magnetically charged second-grade nanomaterial is main novelty of this research. For higher temperature difference, the entropy optimization is used. The defined formulation of stream functions and similarities are used to convert leading second-grade nanofluid model into ordinary differential form. The efficient Keller box method and Newton Raphson technique are applied to compute numerical results. The final algebraic equations are solved through global matrix for unknown physical quantities. The consequence of all physical constraints on velocity/U profile, temperature/θ field, concentration/ϕ shapes, skin friction coefficient, Nusselt and Sherwood number are analyzed pictorially and numerically. The following range of parameters 0.1 ≤ ≤ 2.0, 0.0 ≤ ≤ 1.2, 0.1 ≤ ≤ 2.0, 0.07 ≤ ≤ 7.0, 0.01 ≤ ≤ 0.8, 0.01 ≤ ≤ 0.9 is used. It is found that velocity field increases with maximum amplitude as variable density, magnetic force and temperature-slip constraint. It is noted that the slip behavior in temperature field and concentration field are increased with convective boundary conditions. It is depicted that local Nusselt quantity and local Sherwood quantity increases as buoyancy force and Prandtl coefficient increases.

Evaluation of thermal and concentration slip effects on heat and mass transmission of nanofluid over a moving wedge surface using Keller box scheme

The current research is based on the impact of thermal and solutal slip in the boundary layer nanofluid flow through a moving accelerating wedge. The present investigation is considered with the influence of Brownian motion and thermophoresis. Thermal insulation, geothermal engineering, crude oil extraction, and heat exchangers are very important applications of nanofluid movement over a wedge surface with thermal and concentration slip. The suggested mathematical analysis is expressed in terms of partial differential equations (PDEs). These PDEs are transformed into ordinary differential equations via similarity transformation. The Keller Box technique is used to integrate the resultant non-similar equations. The set of discretized and first order differential equations is formed with the help of central difference and the Newton–Raphson technique. The graphical and numerical results are extracted with the help of MATLAB. The numerical results with the influence of the Prandtl factor (Pr), constant moving factor (λ), thermal slip factor (S2), and concentration slip parameter (S2) are interpreted visually and numerically. Graphical representations of velocity, thermal, and mass concentration profiles are analyzed in depth. The solution for skin friction coefficient, heat transport rate, and mass transport rate is calculated. The moving velocity function increases as Pr increases. The rate of slip temperature and slip concentration rate is enhanced for a lower Prandtl factor. The maximum slip behavior in temperature function and fluid concentration slip is deduced for each value of thermal-slip and concentration-slip factors. For high Prandtl and Brownian motion factors, the rate of Nusselt number is enhanced significantly.

Modeling the bond–slip behavior of the interface between a stiffened core and cemented soil based on machine learning approaches

The bond–slip behavior of stiffened deep cement mixing (SDCM) piles—which is crucial for their bearing capacity—evolves continuously with curing age. In the study reported here, 20 element tests were conducted on the interface between cemented soil and a stiffened core, analyzing the bond–slip behavior affected by curing temperature and age, and then ensemble learning methods (XGBoost, random forest) were used to establish models for the evolution of the bond–slip behavior considering thermal effects. The constructed models can predict the peak shear strength (τmax), the residual shear strength (τres), and the interfacial shear modulus (G). The test results show that the shear strength of the stiffened-core–cemented-soil interface grows with the increasing curing temperature and age, with faster growth at 0–14 days compared to 60–90 days. To lessen the reliance on ineffective brute-force searching, Bayesian optimization with a tree-structured Parzen estimator is used to select the hyperparameters of the established models. The results demonstrate the superior performance of the chosen approach, with R2 > 0.93 for the training set and R2 > 0.81 for the test set. The results of the XGBoost model are best for τmax, with a mean absolute percentage error of less than 5 %, thereby enabling accurate predictions of the mechanical parameters of the stiffened-core–cemented-soil. This research enhances the understanding of the mechanical properties of SDCM piles and provides valuable guidance for projects involving such piles.

Bond–Slip Behavior of Concrete Pile–Cemented Soil Interface Considering Thermal–Temporal Effect: Experimental Study and Constitutive Modeling Based on Disturbed State Concept

Bond–Slip Behavior of Concrete Pile–Cemented Soil Interface Considering Thermal–Temporal Effect: Experimental Study and Constitutive Modeling Based on Disturbed State Concept

Microstructure evolution in laser powder bed fusion melted 2205 duplex stainless steel using in-situ EBSD during uniaxial tensile testing

Compared to duplex stainless steels (DSSs) prepared by traditional methods, specimens produced through laser powder bed fusion (LPBF) exhibit excellent yield strength but lower elongation. To improve elongation, understanding microstructure evolution during uniaxial tensile testing is crucial. This study investigates the slip behavior, grain boundary evolution, and phase transformation of LPBF 2205 duplex stainless steel during tensile deformation using in-situ electron backscatter diffraction (EBSD). Results show the formation of slip bands, which increase in number as loading stress rises. The primary slip systems activated are {110}<111> in ferrite and {111}<110> in austenite. In the ferrite phase, slip dislocations accumulate and generate low-angle grain boundaries (LAGBs), which evolve into high-angle grain boundaries (HAGBs), refining the grain structure. Numerous Σ3 annealing twins form in the austenite phase, but detwinning and twinning reduce Σ3 content as deformation processes. Ferrite and austenite exhibit good stability during the initial stages of tensile deformation. However, some austenite transforms into martensite through the transformation-induced plasticity (TRIP) effect at the final stages of deformation, which helps relieve stress concentration and delays material fracture. This study provides valuable insights for optimizing microstructure to improve the mechanical properties of LPBF materials.

Deformation mechanism of dislocation slip and kinking behaviour in dynamic compression response of TiZrHfNb alloy fabricated by laser directed energy deposition

ABSTRACT In this study, the dynamic response and deformation mechanism of TiZrHfNb RHEA fabricated by laser directed energy deposition (L-DED) were researched under a dynamic compression test at a nominal strain rate of 3500 s−1. The L-DED TiZrHfNb alloy with columnar grains exhibits exceptional mechanical properties with a uniform dynamic flow stress of 1670 ± 10 MPa and a maximum plastic strain of 0.28 ± 0.03. The dislocation slipping and kinking behaviour dominate uniform plastic deformation. First, the dislocations are primarily confined within dislocation channels due to coplanar slip, and the evolution of them in dynamic compressive deformation process has undergone spacing refinement and crossing. Furthermore, the kinking behaviour induced by the lattice rotation with the T = <011> axis denotes the work hardening effect. Particularly, the second kinking behaviour effectively relieves local stress concentration and delays fracture before the formation of adiabatic shear band (ASB).

Crystallographic orientation and slip behavior of powder metallurgy Ti–6Al–4V via multi-directional forging

In this study, we present a microstructural and mechanical analysis of Ti–6Al–4V alloys processed by low-temperature multi-directional forging at 900 °C, achieving near-theoretical density (99.9%), with a tensile strength of 1070 MPa and elongation of 14.9%. The microstructure is defined by both continuous and discontinuous dynamic recrystallization occurring simultaneously, related to an increase in dislocation density. Significantly, this study reveals the interaction between crystallographic orientation and spheroidization during the forging process. Specifically, changes in crystallographic orientation include the asynchronous formation of new subgrains/grains, the disruption of the Burgers orientation relationship, and rotation around the <11 2‾ 0>axis, which not only increases the orientation differences between α lamellae but also enhances the spheroidization process. Moreover, our findings demonstrate that during deformation, the activation of basal and pyramidal slip systems is favored over prismatic slip, indicating that the forging process has enhanced slip activity. The average misorientation angle and the fraction of high-angle grain boundaries are quantified, providing a detailed characterization of the evolved microstructure. This study adopts a new perspective to examine the microstructural evolution during the multidirectional forging process in powder metallurgy, presenting findings that elucidate how multidirectional forging effectively controls.

Internal deformation of the North Andean Sliver in Ecuador-southern Colombia observed by InSAR

Summary In the Northern Andes, partitioning of oblique subduction of the Nazca plate beneath the South American continent induces a northeastward motion of the North Andean Sliver. The strain resulting from this motion is absorbed by crustal faults, which have produced magnitude 7 + earthquakes historically in the Andean Cordillera of Ecuador and southern Colombia. In order to quantify the strain in that area, we derive a high-resolution surface velocity map using InSAR time-series processing. We analyzed 6 to 8 years of Sentinel-1 data and combined different satellite line-of-sight directions to produce a reliable velocity map in the East direction. We use interpolated GNSS data to express the velocity map with respect to Stable South America and remove the long-wavelength pattern due to the post-seismic deformation following the 2016 Mw 7.8 Pedernales earthquake. The InSAR velocity map finds high E-W shortening strain rates along N-S trending structures within the Western Cordillera and the Interandean valley, with little deformation taking place east of them. This result strengthens the previous proposition of a ∼350 km long Quito-Latacunga tectonic block, forming a restraining bend in the overall right-lateral strike-slip fault system accommodating the northeastward escape motion of the North Andean Sliver. However, the high spatial resolution provided by InSAR indicates that previously proposed boundaries for this block need to be revised. In particular, InSAR results highlight high strain rate (&amp;gt;300 nstrain/yr) along undescribed active structures, south and west of the proposed limits for the Quito-Latacunga block, respectively in Peltetec and Ibarra regions. Interestingly, the two areas with the largest strain rates spatially correlate with the proposed areas of large historical earthquakes. Modeling of the InSAR and GNSS velocities in these areas suggests shallow coupling and high slip rates on structures which, previously, were not identified as active. We also demonstrate a slow-down of the shallow aseismic slip on the Quito fault after the Pedernales earthquake, suggesting that stress changes following large megathrust events might trigger transient slip behaviors on crustal faults. The high-resolution strain map provided by this work provides a new basis for future tectonic models in the Ecuadorian and southern Colombian Andes, and will contribute to the seismic hazard assessment in this highly populated area of the Andes.

Bridging Behavior of Palm Fiber in Cementitious Composite

This study addresses the growing need for sustainable construction materials by investigating the mechanical properties and behavior of palm fiber-reinforced cementitious composite (FRCC), a potential eco-friendly alternative to synthetic fiber reinforcements. Despite the promise of natural fibers in enhancing the mechanical performance of composites, challenges remain in optimizing fiber distribution, fiber–composite bonding mechanism, and its balance to matrix strength. To address these challenges, this study conducted extensive experimental programs using palm fiber as reinforcement, focusing on understanding the fiber–matrix interaction, determining the pullout load–slip relationship, and modeling fiber bridging behavior. The experimental program included density calculations and scanning electron microscope (SEM) analysis to examine the surface morphology and diameter of the fibers. Single fiber pullout tests were performed under varying conditions to assess the pullout load, slip behavior, and failure modes of the palm fiber, and a relationship between the pullout load and slip with the embedded length of the palm fiber was constructed. A trilinear model was developed to describe the pullout load–slip behavior of single fibers, and a corresponding palm-FRCC bridging model was constructed using the results from these tests. Section analysis was conducted to assess the adaptability of the modeled bridging law calculations, and the analysis result of the bending moment–curvature relationship shows a good agreement with the experimental results obtained from the four-point bending test of palm-FRCC. These findings demonstrate the potential of palm fibers in improving the mechanical performance of FRCC and contribute to the broader understanding of natural fiber reinforcement in cementitious composites.

Study on the Bond Performance of Epoxy Resin Concrete with Steel Reinforcement

Epoxy resin concrete, characterized by its superior mechanical properties, is frequently utilized for structural reinforcement and strengthening. However, its application in structural members remains limited. In this paper, the bond–slip behavior between steel reinforcement and epoxy resin concrete was investigated using a combination of experimental research and finite element analysis, with the objective of providing data support for substantiating the expanded use of epoxy resin concrete in structural members. The research methodology included 18 center-pullout tests and 14 finite element model calculations, focusing on the effects of variables such as epoxy resin concrete strength, steel reinforcement strength, steel reinforcement diameter and protective layer thickness on bond performance. The results reveal that the bond strength between epoxy resin concrete and steel reinforcement significantly surpasses that of ordinary concrete, being approximately 3.23 times higher given the equivalent strength level of the material; the improvement in the strength of both the epoxy resin concrete and steel reinforcement are observed to marginally increase the bond stress. Conversely, an increase in the diameter of the steel reinforcement and a reduction in the thickness of the protective layer of the concrete can lead to diminished bond stress and peak slip. Particularly, when the steel reinforcement strength is below 500 MPa, it tends to reach its yield strength and may even detach during the drawing process, indicating that the yielding of the steel reinforcement occurs before the loss of bond stress. In contrast, for a steel reinforcement strength exceeding 500 MPa, yielding does not precede bond stress loss, resulting in a distinct form of failure described as scraping plough type destruction. Compared to ordinary concrete, the peak of the epoxy resin concrete and steel reinforcement bond stress–slip curve is more pointed, indicating a rapid degradation to maximum bond stress and exhibiting a brittle nature. Overall, these peaks are sharper than those of ordinary concrete, indicating a rapid decline in bond stress post-peak, reflective of its brittle characteristics.

Surface Migration of Fatty Acid to Improve Sliding Properties of Hypromellose-Based Coatings

Hypromellose (HM) is a cellulose-derived polymer of pharmaceutical grade that forms easily from thin films and coatings. As few studies concern HM-formulated systems, this study focuses on the formulation of HM films by incorporating a fatty acid additive, making it possible to control surface properties such as wetting and slip behavior for pharmaceutical or medical applications. The results show that the addition of a very small amount (from 0.1 to 1% w/w) of fatty acid additive reduces HM film affinity for water and water vapor transmission rate, while film appearance and gloss are rather preserved. Surface properties were probed using wettability measurements, Tapping Mode AFM, ATR-FTIR spectrometry, and friction measurements. Tapping Mode AFM images show that the surface roughness reduces by up to 65%. Wettability results show that the surface energy decreases from 43 to 31 mJ.m−2, whereas surface FTIR spectrometry measurements demonstrate that fatty acid molecules migrate on the surface of the formulated films, the driving force being the microphase separation between the polar HM macromolecules and the hydrophobic additive, leading to the formation of a weak boundary layer with poor cohesion. As a consequence, the surface coefficient of friction significantly reduces from 0.38 to 0.08, and fatty acid molecules thus act as a lubricant, improving the sliding properties of HM-based coatings.

Texture Evolution of High-purity Tantalum during 90°Clock Rolling

Abstract When fabricating high-purity tantalum targets for the sputtering procedure of integrated circuit manufacturing, a through-thickness texture gradient can form in the rolled tantalum (Ta) plate. This texture gradient hinders the target sputtering performance, reducing chip reliability. This study investigated the texture evolution during the 90°clock rolling through experimental and simulation methods. Balancing the plane strain deformation with the surface shear strain deformation during fabrication and limiting the total rolling reduction to no more than 85% can weaken the through-thickness texture gradient in the Ta plate. A crystal plasticity finite element method (CPFEM) model was developed to simulate the 90°clock rolling procedure in the ABAQUS/Explicit software. The simulation and the experimental results are in agreement, with slight differences in texture type and intensity due to tantalum’s complex slip behaviors.

Using a landscape fingerprint to identify changes in fault-slip behavior

The Gabilan mesa tilts gently southwest away from the San Andreas fault in central California (western United States). Rather than attributing its existence to plate convergence, we argue that this large landform developed in response to a change in slip behavior along the San Andreas fault. Our interpretation is based on results from physical experiments. When we isolate a change in slip behavior (i.e., creeping to locked) as the only variable influencing deformation, a half-dome feature forms alongside the slip transition and mimics the shape and location of the Gabilan mesa adjacent to the San Andreas fault. We show other examples of half-dome features along the North Anatolian (Turkey), Philippine, and Chaman (Afghanistan-Pakistan) faults, suggesting that these domed landforms may provide indications of slip behavior transitions on poorly monitored faults.

Experimental Investigation and Analysis of Bond–Slip Behavior between Geopolymer Concrete and Steel Tube with Varying Structural Measures

In this study, push-out tests were conducted on 20 specimens to explore the bond–slip performance of geopolymer concrete-filled steel tubes. The investigation focused on the effects of various design parameters such as length–diameter ratio, diameter–thickness ratio, concrete strength, and internal structural measures of the steel tube on the bond–slip performance. Analysis of the test phenomena, load–slip curves, and strain distribution curves of each specimen revealed insights into the shear strength calculation methods for welded stud structure and ring rib structure specimens. The results indicated a slight buckling deformation at the loading end of the steel tube in the structural specimen, while no significant deformation was observed in the non-structural specimen. The strain distribution along the height direction of the steel tube exhibited a triangular pattern, with the strain increasing gradually. Improvements in the interfacial bonding performance were noted with reductions in length–diameter ratio and diameter–thickness ratio of the steel tube, as well as increases in concrete strength. When the steel tube wall thickness t increases from 3.5 mm to 4.5 mm, the peak load of GC30-1 increases from 382.13 kN to 419.59 kN, an increase of 9.81%. After improving the concrete strength of GC30-1 and GC30-3 specimens, the peak load increases from 382.13 kN and 274.54 kN to 436.46 kN and 306.12 kN, respectively, an increase of 14.2% and 11.5%. Furthermore, the welding structure of the steel tube significantly enhanced the shear bearing capacity of the interface. The ratio of load calculation value to test value fell within the range of 0.917 to 1.098, indicating good agreement between the calculated and experimental values. These research results can provide reference for engineering applications of geopolymer concrete.

Explosive stress wave propagation and fracture characteristics of rock-like materials with weak filling defects

Filling-type defects have a non-negligible effect on the propagation of explosive stress waves in rock. Combined with the new dynamic caustics experimental system and ANSYS/LS-DYNA numerical simulation platform, the research on the propagation characteristics of explosive stress wave and fracture characteristics of rock-like materials containing weak filling defects with different ductility has been carried out. Firstly, we analyzed the influence of weak filling on the propagation of blast-induced cracks, explored the “guiding” and “stopping” effects of weak filling on cracks, and analyzed the mechanical characteristics of crack propagation. Secondly, the effect of planar weak filling ductility on the damage degree of blasted medium was quantitatively evaluated. Thirdly, the influence of weak filling on the fluctuation characteristics of explosive stress wave was investigated. Then, the mechanical response behavior of the specimens was analyzed, and the results showed that the compaction and slip behaviour characteristics of the weak filling have some variability in degree, some continuity in time, some correlation in space and are affected by the ductility of the planar weak filling. In addition, the stress wave and weak filling interaction mechanism was elucidated. The conclusions of the analysis have positive reference value for understanding the explosion mechanics mechanism of defective rock masses.