Joint roughness and aperture critically influence the shear failure and crack propagation of non-persistent joints, affecting rock mass strength and stability. This study develops a non-persistent joint model in ABAQUS using a finite element-cohesive zone model (FEM-CZM) method, where cracks are represented by deleting failed cohesive elements. The effects of joint roughness coefficient (JRC), aperture, and normal stress on shear response, stress evolution, and crack propagation are analyzed. Results show that peak and residual shear stresses increase with JRC and normal stress, whereas peak shear stress decreases with aperture; residual shear stress exhibits no clear trend with aperture. Cracks initiate at rock bridge tips; higher JRC promotes earlier initiation and wider propagation. Larger apertures lead to more localized cracking and increase tensile crack proportions. Higher normal stress accelerates crack coalescence, shifts failure from tensile to shear-dominated modes, and produces straighter shear surfaces. Total crack count rises with JRC and normal stress but initially increases and then stabilizes with aperture. Tensile cracks account for approximately 61-81% of all cracks and dominate near rock bridges, while shear cracks concentrate near joint surfaces. These insights provide guidance for stability assessment and the design of reinforcement measures in rock masses with non-persistent joints.

Supercritical CO2 (ScCO2) plays a crucial role in enhancing coalbed methane recovery and CO2 geological sequestration. Currently, predicting gas flow remains a major scientific challenge due to difficulties in coupling multiple physical fields. The reasons for discrepancies between observations from laboratory and field studies and model predictions remain unclear. This paper reviews nearly 20 projects funded by the National Natural Science Foundation of China and several related publications on coal-gas interactions under ScCO2. Recent advances are systematically summarized, focusing on multiscale coal damage characteristics and multiphysics gas transport. The fracture propagation and pore structure evolution of coal are analyzed at macro-, meso-, micro-, and molecular scales. Models that assess the effects of cleat structure and mechanical coal damage on permeability under constant-volume conditions are reviewed. The importance of developing a coupled damage-stress-flow-thermal model to elucidate gas transport mechanisms under free-expansion conditions is highlighted. Moreover, the main factors affecting CH4 displacement by ScCO2including coal adsorption properties, CO2 concentration, and mechanical coal deformationare examined. The effects of these factors on physical field distributions and displacement mechanisms are also analyzed. Finally, future research priorities for CO2-enhanced (CO2-ECBM) recovery in experimental, simulation, and field applications are proposed.

The damage evolution laws and failure characteristics of rocks subjected to wetting-drying cycles are critical for the stability control of rock mass engineering. This study conducted uniaxial compression tests on red sandstone samples subjected to varying numbers of wetting-drying cycles, along with simultaneous Acoustic Emission (AE) and Digital Image Correlation (DIC) monitoring, to systematically analyze the influence mechanism of water-rock interaction on the rock’s mechanical behavior. The experimental results indicate that after 20 wetting-drying cycles, the compressive strength and elastic modulus of the red sandstone decreased by 46.82% and 56.03%, respectively. Furthermore, as the number of wetting-drying cycles increases, a significant reduction is observed in both the AE energy release rate and the b-value, accompanied by an increase in the proportion of large-scale fractures and a concurrent reduction in the number of AE localization events. As the cumulative effect of water-rock interaction progresses, the axial displacement at characteristic points on the sample surface exhibits a three-stage evolution pattern: "slow decay, steady-state development, and rapid instability". The initiation locations of macroscopic fractures show spatial consistency with the areas of maximum strain concentration on the sandstone surface. Moreover, a damage constitutive model was established based on the Weibull probability density function, which effectively characterizes the evolution of AE counts with strain in rock samples during uniaxial compression.

The shear behavior and failure mechanisms of non-persistent joints are key to the stability of jointed rock masses, whose shear responses are jointly governed by geometric parameters such as joint aperture and joint persistence. In this study, direct shear tests were performed on specimens containing coplanar non-persistent joints, and the shear-failure process was simulated using the finite element method-cohesive zone model (FEM-CZM) method. The combined effects of joint aperture and joint persistence on shear behavior were investigated from both macroscopic and mesoscopic perspectives, and an improved Jennings shear strength criterion incorporating the weakening effect of joint aperture was derived. The tests revealed two typical post-peak failure patterns: a "sudden drop followed by arcuate recovery" and a "stepwise decline". Increases in both the joint aperture and joint persistence reduce the peak shear strength, with joint persistence exerting a more pronounced influence. Larger joint apertures increase the degrees of rock bridge fracture surface undulation and specimen surface spalling, whereas higher joint persistence flattens the fracture surface and mitigates surface spalling. Simulations indicate that stress initially concentrates at the rock bridge ends and extends towards the middle during shearing. The number of cracks increases sharply at the peak shear stress, with tensile cracks consistently dominating. Larger joint apertures intensify the stress concentration at the rock bridge ends, leading to earlier crack initiation, a more vigorous crack propagation trend, and more dispersed crack paths, whereas higher joint persistence narrows the stress concentration zone and accelerates crack coalescence across the rock bridge. Finally, based on the test and simulation results, an improved Jennings shear strength criterion is proposed by introducing a cohesion reduction coefficient eta(d) that decays exponentially with joint aperture. The validation results demonstrate that the predicted peak shear strengths agree well with the measured values and external data.

The microstructure of crystalline rock comprises mineral aggregates and randomly distributed microcracks that strongly govern macroscopic mechanical behavior. However, existing numerical approaches struggle to simultaneously capture finite-width microcrack closure, mineralogical heterogeneity, and realistic compressive-to-tensile strength ratios. This study develops a three-dimensional heterogeneous rock model within a finite-discrete element method (FDEM) framework that explicitly represents the polycrystalline mineral structure and embeds microcracks with prescribed intensity and finite aperture. Systematic uniaxial compression simulations on granite show that increasing microcrack width and intensity increases both crack-closure strain and crack-initiation strain, while decreasing crack-closure stress and crack-initiation stress. The crack-closure stage becomes more pronounced with increasing microcrack intensity and width, but via distinct mechanisms: higher intensity lowers the initial tangent modulus, whereas greater width extends the crack-closure strain range. Increasing microcrack intensity and width reduces elastic modulus and uniaxial compressive strength, with intensity exerting the stronger influence. As intensity increases, the failure mode transitions from localized shear fracture to diffuse fragmentation. Based on these parametric analyses, we establish an efficient calibration procedure for FDEM micromechanical parameters that incorporates microcrack characteristics. The calibrated model shows excellent agreement with laboratory measurements (relative errors < 5%), reproducing the nonlinear compaction stage and granite's high compressive-to-tensile strength ratio. Applications to thermo-mechanical and hydro-mechanical coupling demonstrate that the model captures temperature-induced strength degradation and stress-controlled hydraulic fracture propagation in microcracked granite. This work provides a physically consistent framework for modeling the nonlinear compaction behavior and strength characteristics of crystalline rocks.

Understanding the shear mechanical behavior and degradation mechanisms of rock mass joint surfaces subjected to wetting‒drying cycles is crucial for the optimized treatment and early hazard warning in slope engineering. In this study, sandstone joint samples with identical surface morphologies were fabricated using 3D engraving technology. Shear tests were conducted on these samples after they were exposed to different numbers of wetting‒drying cycles. Coupled with real-time acoustic emission (AE) monitoring, this research systematically examines the degradation patterns and damage evolution mechanisms governing the shear mechanical behavior of joints under cyclic wetting–drying conditions. The results demonstrate that the shear mechanical parameters decrease progressively with increasing number of wetting‒drying cycles. After 5 to 15 wetting‒drying cycles, the peak shear strength of the sandstone joints decreased by 14.5

Geothermal energy extraction and unconventional oil and gas production inevitably result in cooling shocks for high-temperature rock masses. In this study, the mode I fracture characteristics and failure mechanisms of granite under different temperatures (20-400 degrees C) and cooling methods (air cooling and water cooling) were investigated. Heat-treated semi-circular bend specimens were subjected to three-point bending tests. A formula for calculating the elastic modulus of SCB specimens was proposed. Advanced characterization techniques, including digital image correlation for fracture process zone (FPZ) and crack tip opening displacement (CTOD) measurement, 3D laser scanning for fracture surface morphology analysis, and scanning electron microscopy for fracture surface microstructure examination, were systematically employed. A 3D heterogeneous numerical model was established to study granite temperature and stress changes during heat treatment. The integrated experimental and numerical results reveal the influence of cooling methods on granite fracture mechanisms. As the heating temperature rose, fracture toughness, strain energy, and energy-release rate decreased, whereas the elastic modulus first grew and then decreased. Compared with air cooling, water cooling caused more significant deterioration to the mechanical properties of granite. At the peak load stage, both FPZ length and critical CTOD grew with heating temperature, with a notable increase at 400 degrees C. However, the FPZ width did not change significantly. Water-cooled granite consistently exhibited longer FPZs and higher critical CTODs than air-cooled granite. With increasing temperature, the surface roughness coefficient increased, but the tortuosity first increased, then decreased. It was found that water cooling resulted in more tortuous fracture paths and rougher fracture surfaces, as well as lower fracture permeability. These findings can provide theoretical and engineering guidance for enhancing deep energy extraction efficiency.

Rock mass defects, such as holes, fissures, and weak infillings, critically compromise the safety and stability of engineering rock masses. The macromesoscopic mechanical behaviour and damage evolution mechanisms of defective rock masses under biaxial compression remain insufficiently understood. In this work, red sandstone samples with hole-fissure defects were prepared via waterjet cutting, and uniaxial and biaxial compression tests were performed. The finite element method-cohesive zone model (FEM-CZM) method was employed to simulate the compressive failure process of the defective sandstone models. The influence mechanisms of the fissure angle, confining stress, and infilling conditions on the mechanical properties, failure modes, and damage evolution were investigated systematically. The experimental results revealed that the samples displayed pronounced brittle failure characteristics in the postpeak stage, with increased brittleness at higher confining stresses. The peak compressive strength and elastic modulus were positively correlated with the fissure angle and confining stress, whereas the peak axial strain was negatively correlated with the confining stress. Hole collapse (HC) cracks were considerably reduced in the infilled samples, and surface spalling (SS) cracks were more prevalent under biaxial compression. The numerical results revealed that during the initial compression stage, the cohesive elements exhibited almost exclusively tensile failure characteristics. The presence of infill effectively restricted the plastic deformation induced by uneven stress distribution at rock mass defects, resulting in earlier damage in the unfilled models than in the infilled models. As the fissure angle increased, the crack initiation mechanism shifted from tensile-dominant failure due to tensile stress concentration to shear-dominant failure due to compressive stress concentration. The number of failed cohesive elements was positively correlated with the fissure angle and the confining stress, whereas the proportion of tensile failure was negatively correlated. For the infilled models, the number of failed cohesive elements and the proportion of tensile failures were considerably lower than those of the unfilled models. This study enhances the understanding of the damage mechanisms in rock masses with hole-fissure defects under biaxial compression, providing theoretical support for rock engineering design and stability assessment.

Depressurization production causes reservoir deformation to change the physical and mechanical properties, thus affecting the fluid flow and production performance. The mechanical deformation and gas production characteristics of multilayer hydrate reservoir at the first depressurization production site in the Shenhu area need to be further simulated and investigated. In this paper, a multilayer hydrate reservoir model is established based on the real logging data of SHSC-4 well, and the simulation results are compared with the test production results to verify the model validity. The production performance and reservoir stability are evaluated by considering reservoir deformation and gas production behavior, and the CO2 reinjection potential of the multilayer reservoir after production is analyzed by numerical methods. Low production pressure can serve to increase cumulative gas production, but reservoir deformation can also be an unfavorable factor hindering gas production. The negative effects of reservoir deformation caused by depressurization on gas production results need to be considered when numerical methods are used to evaluate reservoir production performance or optimize production design. Percentage contribution of free gas layer (FGL) decreases with the reduction of production pressure, and the gas production from the reservoir is mainly from hydrate-bearing layer (HBL) and three phase layer (TPL). There is a turning point in the production performance of HBL and TPL around 3 MPa. The gas production performance of HBL is better than TPL when the production pressure is lower than 3 MPa, and the percentage contribution of HBL and TPL are about 40% under different initial inherent permeability conditions. Permeability enhancement measures promote the propagation of low pore pressure in the reservoir, which is prone to cause large reservoir deformation. CO2 reinjection leads to reservoir uplift around production well, and stress concentration distribution induced by depressurization production are mitigated. TPL has better CO2 reinjection potential than FGL and HBL, and it accounts for about 50% of the total reinjected gas.

Under cyclic loading, rock joints underwent continuous slipping and closure, resulting in fatigue damage to the joints and thereby affecting the stability of rock engineering projects. To investigate the fatigue shear characteristics of joints under cyclic stress, numerical simulations of rough joints under cyclic shear stress, involving variations in normal stiffness, loading amplitudes, and loading frequencies, were performed using a cyclic shear loading method based on the FISH language. The results indicated that there was a hysteretic effect in the shear stress–shear displacement curves of joints. During cyclic shear stress, the shear velocity of the joint fluctuated from positive to negative, with the maximum shear velocity changing by approximately 10 times, increasing from 0.012 × 10–2 to 0.15 × 10–2 mm/s before and after joint instability. As normal stiffness increased to the same shear displacement, more cracks developed in the joint. When the normal stiffness exceeded 3 GPa/m, a conspicuous failure zone was evident. Loading amplitude showed an inverse proportionality to the number of cycles required to achieve the target shear displacement. Loading frequency exhibited a linear proportionality to the number of cycles needed to reach the target shear displacement The fatigue damage degree of joints during cyclic shear could be represented by two indices: the Felicity ratio (FR) and the damage variable (D). Under different conditions, the critical D value ranged from 0.037 to 0.097, while the corresponding critical FR value varied between 0.700 and 0.822, reflecting the impact of normal stiffness, amplitude, and frequency on joint fatigue failure.

Filled joints are widely found in natural rock masses and are one of the main factors causing rock mass engineering instability. The use of bolts can effectively control the shear slip of filled joints, research on bolts filled joints in the filling degree, and other key parameters of the influence of the law, to ensure the stability of the engineering rock body is of great significance. This paper presents shear experiments on bolted filled joints of Basalt Fiber-Reinforced Polymer (BFRP) materials with different joint roughness and filling degrees, while acoustic emission technology monitors the shear failure process of the specimens. The results show that the peak shear strength decreases with the increase in filling degree, and the peak shear strength decreases by 23.9% when the filling degree changes from 0 to 2.0 at 4 MPa and J2 conditions, while the normal stress, the Joint Roughness Coefficient (JRC) and the peak shear strength both show a positive correlation. The normal deformation of bolted filled joints exhibits three distinct evolutionary patterns depending on the filling degree, while both JRC and normal stress significantly influence the magnitude of shear dilatancy-shrinkage deformation. The shear resistance of BFRP bolts is mainly reflected in the post-peak plastic stage, and some of the fibers break during its shear deformation to form controlled yielding, with vertical and horizontal deformation controlled within 15.5~22.3 mm and 4.7~6.9 mm, respectively. The Acoustic Emission (AE) results show that the AE events are mainly in the post-peak plasticity stage, and the proportion is about the sum of the proportion of the other two phases, and this proportion increases with the increase in the filling degree.

The mechanical response and damage evolution characteristics of pillar-backfill composite structures (PBCS) under cyclic loading are critical for the long-term stability of goaf areas in deep metal mines. This study systematically investigates the synergistic effects of initial disturbance value (sigma), number of cycles (T), amplitude (A), and frequency (f) on the mechanical properties, damage accumulation, and failure modes of PBCS through laboratory experiments combined with multi-field monitoring techniques, including acoustic emission (AE) and digital image correlation (DIC).The results indicate that increasing initial disturbance value significantly deteriorates the mechanical performance of samples, with uniaxial compressive strength (UCS) and elastic modulus (E) decreasing by 20.22 % and 16.67 %, respectively. When sigma exceeds 60 % UCS, the irreversible strain growth rate increases to 1.9 times that of low-disturbance conditions, revealing a nonlinear acceleration effect of pre-damage on crack network coalescence. Higher amplitude leads to a decreasing trend in irreversible strain increments, suggesting a shift in damage mechanisms from microcrack propagation to macroscopic fracture dominance under highamplitude loading. Under high initial disturbance value, the cumulative AE count decreases more significantly than the AE count, confirming that pre-damage inhibits subsequent crack initiation by enhancing energy dissipation. The failure mode of PBCS is jointly controlled by sigma and A, transitioning from single shear-dominated failure under low disturbance to tensile-shear composite failure under high disturbance and high amplitude, accompanied by multi-crack cooperative propagation and strain localization network formation. Furthermore, frequency exhibits a non-monotonic influence on mechanical performance, with the lowest damage accumulation rate observed at 4 Hz, while high-frequency vibration (8 Hz) temporarily enhances strength by 4.26 % due to particle densification. These findings provide a theoretical basis for optimizing support design and preventing dynamic hazards in backfill systems under cyclic disturbances in deep mining.

To investigate the mechanical behaviour and failure mechanism of flawed rock masses under biaxial stress conditions, a series of biaxial compression experiments are conducted on red sandstone specimens containing combined flaws of the circular hole and perforated symmetric fissure combined with acoustic emission (AE) technology in this work. The results show a close association between the stress–strain curve morphology and confining stress, both the biaxial compression strength and elastic modulus exhibit an upward trend with increasing fissure angle and confining stress. The maximum AE energy and cumulative AE energy both increase with higher confining stress. The crack types in the specimens are identified by analyzing the average frequency/rise time/amplitude value distribution, revealing a gradual decrease in the percentage of tensile cracks with increasing fissure angle. An AE localization algorithm based on the least absolute value method is applied to pinpoint AE events during biaxial compression, and AE events distribution is analyzed through the kernel density estimation. The crack extension behaviour is described based on the movement of the maximum kernel density points, which initially exhibits a progression from both ends of the specimen toward the central region and subsequently from the central fissure tip toward the two ends.

Under prolonged cyclic disturbances such as rockbursts and repeated excavation activities, the stability of pillarbackfill composite structures (PBCS) progressively degrades. To elucidate the effects of layered backfill on the mechanical properties and damage evolution of pillar-backfill systems under cyclic loading, this study conducted experiments using a low-frequency cyclic loading system integrated with acoustic emission (AE) monitoring and digital image correlation (DIC) techniques. The investigation focused on analyzing the stress-strain behavior, AE signatures, and crack propagation mechanisms in layered backfill specimens with varying cement tailing ratios (CTR). The results indicate that: (1) As the CTR decreases, the compressive strength of the composite structure significantly decreases, while its deformation capacity increases. The presence of layered structures weakens the overall load-bearing performance of the PBCS and delays the occurrence of plastic deformation. The impact of dynamic disturbance stress exhibits a critical threshold: below this value, the disturbance enhances material strength, while above this value, it accelerates damage accumulation. (2) AE signals reveal that crack propagation in monolithic cast samples is relatively slow, with AE events distributed more uniformly. In contrast, layered cast samples exhibit stronger fluctuations in AE signals due to weak interlayer interfaces, resulting in more intense crack propagation. Layered backfill demonstrates certain resistance to disturbance under highdisturbance conditions, but the interlayer bonding strength requires further optimization. (3) b-value analysis shows that the evolution of microcracks advances with decreasing CTR, and large-scale cracks form earlier. As the initial disturbance value increases, the rate of damage accumulation significantly accelerates, and the samples enter the accelerated failure phase at lower stress levels. (4) The crack propagation path in PBCS samples is relatively simple, primarily extending along the direction of maximum principal stress. In contrast, cracks in layered cast samples predominantly propagate along the interlayer interfaces, and with increasing initial disturbance stress, the crack network becomes more complex, and the failure range expands significantly. These findings provide a theoretical basis for the design and optimization of backfill structures in deep mining.

The shear resistance of multi-joint rock masses significantly affects the stability of underground engineering structures. In this work, using 3D printing technology, rock-like samples containing two joints with varying joint spacings and roughness values are prepared and subjected to direct shear tests under different normal stress conditions. The results demonstrate that the shear stress-shear displacement curve is influenced by the joint roughness coefficient (JRC) and normal stress. Peak shear stress increases with increasing JRC and normal stress but decreases with increasing joint spacing. Increases in JRC and normal stress increase the shear stress softening. The primary failure mode of the double-joint samples involves rock interlayer fracturing, the joint spacing has a smaller impact on shear failure mode than the JRC and normal stress. The shear failure behaviour and microcracking mechanism of a double-joint sample are revealed based on the developed cohesive zone model (CZM) method. Numerical tests revealed that the number of cracks in the double-joint model increases with increasing JRC and normal stress but decreases with increasing joint spacing. The model results in significantly more tensile cracks than shear cracks, tensile cracks are predominantly located in the rock interlayer of the double-joint model, whereas shear cracks are concentrated near the joint surfaces. This study explores the shear mechanical characteristics and microdamage behaviour of double-joint rock masses and offers foundational insights into the shear failure mechanisms of complex multi-joint rock masses.

The shear behavior of the Bolt-Grout interface has a significant effect on the stability of a bolting system. In this paper, a series of shear tests were conducted on Bolt-Grout interfaces, and the effects of rib spacing, rib angles, and normal stress on the shear characteristics and failure modes of the Bolt-Grout interface were investigated. The results showed that the shear strength varied nonlinearly with an increase in rib spacing and angle, and also that it increased linearly with an increase in normal stress. With smaller rib spacings, the effect of rib spacing on peak shear strength was more apparent. The failure modes of the interface can be categorized as shear-slip failure, shear-break failure, and composite failure. The proportion of shear-slip failure and shear-break failure mainly depends on the rib spacing, rib face angle and normal stress.

AbstractThe deformation and failure of coal walls in front of a working face cause significant difficulties during mining operations. This study reveals the nonuniform distribution of bearing pressure in front of coal walls based on in situ monitoring data and numerical simulation. Therefore, an eccentric compression mechanical model was established to study the deformation and failure characteristics of a coal wall. The slenderness ratio of the compression bar is introduced to define coal walls. The results showed that instability failure occurs when λ > λc and material failure occurs when λ ≤ λc. The instability failure‐type coal wall spalling was related to the mining height, eccentricity of roof pressure, the horizontal force, and the reaction moment of the floor. The material failure‐type coal wall spalling was related to the cohesion, the internal friction angle of the coal, the upper pressure, and the horizontal force of coal walls. Unstable and destructive coal wall peeling usually occurs at a height of 0.5–0.6 times the mining height, while material damage to coal wall peeling is determined to occur within the range of 0.4–0.6 times the mining depth. The findings contribute to the understanding of the deformation and failure of coal walls.

Understanding the shear characteristics and acoustic emission features of bolted joints is crucial for the optimization of support systems and disaster early warning. In this paper, a series of shear tests on rock joints using both full-length anchorage and partial anchorage methods were conducted. The evolving patterns of shear mechanical characteristics and acoustic emission features of bolted rock joints were obtained, elucidating the influence of anchorage methods and revealing the shear failure mechanisms of joints under different anchorage lengths. The results indicate that the “pin effect” of the bolt can be rapidly mobilized in the full-length anchorage compared to the partial anchorage method. The full-length anchorage exhibits higher peak shear stress and fracture shear stress, with maximum differences of 0.38 MPa and 0.08 MPa, respectively, when contrasted with the partial anchorage method. The deformation range of bolts in the partial anchorage method approximately doubles that observed in the full-length anchorage. Acoustic emission feature parameters exhibit a good correspondence with shear stress curves, and their evolution suggests that the most significant damage to bolted joints occurs at the shear stress peak, with the highest energy release observed when bolts fail. Under both partial anchorage and full-length anchorage, with an increase in normal stress or JRC, the b of bolted joint acoustic emissions gradually decreases. Compared to the partial anchorage method, the full-length anchorage demonstrates a higher maximum Hit rate, along with lower maximum energy release, implying more intense interaction between bolts and surrounding rock in the full-length anchorage, resulting in greater damage under the same conditions, whereas the deformation range of bolts is smaller, and the energy released upon failure is lower in the full-length anchorage.

Sediment compression during submarine hydrate depressurization production causes changes in physical and mechanical characteristics, which in turn affects production results. In this paper, based on geological conditions of SHSC-4 well in Shenhu area, a theoretical model considering sediment compression effects is established by COMSOL, and the effects on the evolution of reservoir physical and mechanical characteristics within 60 days during depressurization production is simulated. The results show that model dimension effects can be ignored when the size l >= 100 m within 60 days. The effects of sediment compression on the physical characteristics of the reservoir are mainly realized by affecting the evolution of porosity, and the porosity reduction leads to permeability reduction. The larger the sediment compression coefficient, the higher the pore pressure in the reservoir. Sediment compression hinders the propagation of low pore pressure and heat transfer in the reservoir, which is unfavorable for hydrate decomposition favorable to hydrate reformation. A larger or smaller sediment compression coefficient selected in the simulation can lead to under- or over-estimate of reservoir gas production, so choosing an appropriate sediment compression coefficient when considering sediment compression is necessary for rational assessment of reservoir production behavior. In the production test site, when the production pressure is higher than 3 MPa, the pore pressure gradient is the key factor to promote gas production from the reservoir. When the production pressure is lower than 3 MPa, the sediment compression is the key factor to impede gas production from the reservoir.