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In order to explore the mechanism of rockburst in tunnels constructed by drilling and blasting method in high ground stress strata, this study reformed the physical model test system of rockburst in deep tunnels and the high-pressure gas explosion excavation system, and successfully reproduced the process of rockburst disaster in drilling and blasting construction. Based on the existing research results and preliminary tests, a composite material with similar brittleness and rock burst tendency index to the granite on site was developed, and a cubic rock burst model of 500 × 500 × 500 mm 3 was poured. The test results show that in the gas explosion excavation, the air pressure impact causes the test block to be destroyed instantaneously, the small fragments splash and the explosion sound is significant, indicating that the instantaneous release of gas can cause material damage and simulate the dynamic characteristics of the blasting process. From a macro point of view, rockburst originates from the stress adjustment of surrounding rock of the cavern and the energy transfer and dissipation process inside the rock mass. The residual energy is released in the form of dynamic energy and dissipated by dynamic mechanism. Microscopically, the material is compressed and destroyed in a small range of gas explosion tube pores, and the surrounding rock debris is mainly tensile and shear failures. The shear and tensile stress make the tunnel damage debris complex. The test results show that the stress at the measuring point 3 cm away from the cavern after excavation drops sharply at T = 11915s, with a decrease of 56.69%. At 30.50 cm from the cavern, the strain at the measuring point 3 cm from the cavern increases. The sharp rise of acoustic emission count and energy indicates that the rock burst phenomenon is sudden. The test method of this study effectively simulates the rock burst of tunnel constructed by high ground stress drilling and blasting method, which provides important experimental basis and data support for theoretical research and engineering practice of rock burst.

To accurately understand the deformation behavior of surrounding rock in the jiugongshan No.2 high ground stress tunnel and optimize construction parameters for improved efficiency, on-site monitoring was used to gather data on rock deformation and initial support contact pressure. A WOA-LSTM regression prediction model was proposed, and excavation advance depth was optimized using numerical simulation. The WOA-LSTM regression prediction model demonstrated high accuracy in tunnel deformation monitoring. The absolute errors between predicted and actual values of tunnel settlement and convergence at various measurement points average 2.53 − 04  mm and 1.96 − 04  mm, with relative errors averaging 2.15% and 2.34%. These results meet the requirements for guiding construction. Additionally, based on the results of numerical simulation calculations, when the step length is 12 m during the construction of high-stress tunnels using the benching method, excavation advances of 2 m and 3 m result in settlement and convergence increases of 35.1% and 63.4%, and 25.5% and 55.2%, respectively, compared to an excavation advance of 1 m. However, no sudden jumps in these values were observed, indicating that with a 3 m excavation advance, the integrity of the surrounding rock remains in good condition, effectively guiding safe and rapid construction methods.

Aiming at the crucial engineering challenge of the ambiguous excavation deformation mechanism of hard and brittle surrounding rock under high geos-tress conditions, with the right bank diversion tunnel at the dam site of the hydropower station as the research object, the deformation and failure characteristics of the surrounding rock and their formation mechanisms during the layered excavation of the diversion tunnel were investigated. The research findings show: (1) The main factors influencing the deformation of the diversion tunnel’s surrounding rock are the high ground stress environment, the degree of fracture development in the rock mass, and the effectiveness of the support system. (2) Following the excavation of the first layer, extensive shallow damage predominates, with damaged blocks primarily exhibiting sheet-like and plate-like forms. After excavating the second and third layers, there is a significant reduction in confining pressure in this region, leading to a rapid deterioration in the extent of damage. (3) Layered excavation induces ‘time-dependent’ variations in the yield characteristics of the surrounding rock, while simultaneously being influenced by the location and extent of fracture development. The study results are expected to provide a theoretical basis for the excavation of underground caverns under high ground stress.

Deep underground excavation is a complex loading and unloading process with increasing tangential stress and decreasing radial stress, and the evolving mechanical properties of the rock mass following excavation and unloading require urgent investigation as current underground engineering reaches deeper. Most of the existing surrounding rock failure simulations apply loads after excavation and prove insufficient to simulate the stress paths during excavation and unloading in actual projects. This study designed the excavation function based on the variable angle triaxial test device developed in our previous research to simulate the loading first, tunneling later stress path in the unloading process during actual tunneling. Preliminary tests were conducted to simulate the excavation unloading of the vertical and horizontal maximum principal stresses. The internal damage evolution of the surrounding rock was investigated based on the acoustic emission (AE) spatiotemporal responses and the numerical simulation model. Analysis of the crack evolution in the two types of excavation tests indicated that the basic AE parameters became active before and after reaching the constant load, and the AE counts showed significant growth. The b -values remained essentially unchanged before and after the excavation, and no significant large-scale cracking was induced during excavation in the rock specimens. The cracks during rock failure can be effectively categorized based on the RA-AF values, and the results indicated comparable numbers of tensile and shear cracks before and after excavation. The excavation unloading simulations of two different stress paths revealed that the surrounding rock tended to retain its overall structure integrity after excavation, and no obvious cracks were observed around the tunnel on the two sides. Analysis based on the 3D discrete element excavation failure model found that the excavation test was dominated by tensile cracks, with shear cracks primarily distributed closely around the tunnel. The tests verified the feasibility of the excavation function in the variable angle true triaxial test device, which can provide useful references for subsequent research on surrounding rock unloading damage.

Waste tire disposal and high-ground-stress soft rock roadway instability are pressing global challenges. This study develops sustainable rubber granule concrete (RGC) using waste tire rubber as a key component, aiming to realize waste valorization and floor heave control. RGC’s mechanical properties (uniaxial/triaxial compression, compressibility, ductility) were systematically tested, and its pressure relief mechanism was validated via finite element analysis (ABAQUS/FLAC) and 60-day field monitoring. Results show that RGC with optimal parameters (12% rubber content, 3–4 GPa elastic modulus, 250–350 mm thickness) achieves 64% bottom stress reduction and >40% displacement control. The material’s excellent energy absorption and flexibility address the brittleness of conventional concrete, ensuring stable support in high-stress environments. This work provides a sustainable, cost-effective concrete modification strategy, bridging waste recycling and geotechnical engineering, with broad implications for low-intensity, high-toughness material applications.

To investigate the mechanical behaviors of failure and rockburst proneness of fractured rock mass during excavation unloading under high in-situ stress. Triaxial loading and unloading tests of fractured rock samples with different dip angles under different stress paths were conducted, and mechanisms inducing catastrophic effects of deeply buried fractured granite were discussed from the perspectives of mechanical characteristics of failure and energy evolution. The results imply that failure modes of fractured granite under triaxial loading and unloading are mainly dominated by shear failure. Coplanar cracks produced by granite under unloading generally often are composite tensile-shear cracks, which show more significant brittle failure. Under loading and unloading, the energy storage limit Uem of rock first decreases, then increases with the increase of the dip angle of fractures. When the dip angle of prefabricated fractures is closer to the fracture angle of the intact rock mass, the energy storage limit is smaller and shows an increasing linear relationship with the unloading ratio. The rate of change of elastic strain energy in fractured rock under triaxial loading suddenly increases more frequently. The elastic energy release rate δ was defined to evaluate the rockburst proneness of deeply buried fractured granite under loading and unloading. Under unloading, the elastic energy release rate δ of rock is slightly affected by changes of the dip angle; the elastic strain energy in the rock is rapidly released, greatly increasing the rockburst proneness.

Damage to tunnel lining significantly influences the stability of tunnels during operation, particularly under conditions of extra-high ground stress. This article investigates the stability of tunnel linings subjected to extra-high ground stress, providing an in-depth analysis of crack damage modes. A time-varying reliability model based on the structural performance function is proposed, which incorporates the effects of the plastic zone and the identified crack damage modes. The plastic zone and the distribution of the surrounding rock stress field throughout the excavation process were simulated, elucidating the relationship between vault displacement and stress release rate. The time-varying reliability model is employed to assess lining behavior under extremely high ground stress and to establish the patterns governing its service life. The findings of this study offer a crucial reference for further investigations into the time-varying reliability of tunnel linings in the context of extreme ground stress.

Under the coupling action of high ground stress and water environment, the physical and mechanical properties of backfill will change to some extent, and then secondary compression will occur. In this study, a prediction model of surface subsidence in deep filling mining was established through the combination of physical tests and theoretical analysis. First, the foundation coefficient of complex lithologic gangue under the coupling of high ground stress and water environment is determined, and then the prediction model of roof deflection in deep filling mining is established. Then, based on the hypothesis of conservation of subsidence space, the similarity theory and random medium theory are used to transfer the roof deflection to bedrock and the loose layer, and the accurate prediction of surface subsidence in deep filling mining is finally realized. The results show that the secondary compression of compound lithologic gangue under the influence of water environment is about 6.9%–8%. With Yingpanhao coal mine as the geological background, the relative errors of roof deflection, sandstone face of the Zhidan Group and loose layer are 1.5%, 1.1%, and 2.3%, respectively, which can accurately predict surface subsidence.

Tunnels excavated in a combination of hard and soft rock strata with high ground stress are prone to large deformations, collapse, and other disasters. The Yongfeng Tunnel, a reconstruction and expansion of the G544 line, suffered severe high ground stress from plate compression. This paper studied the surrounding rock pressure and supporting structure stress characteristics of tunnels with a combination of hard and soft rock strata with high ground stress by using earth pressure cells, surface strain gauges, and embedded strain gauges to test all stress related to the surrounding rock, primary support, and secondary lining. It was found that the contact pressure (P1) between the initial support and the surrounding rock and the contact pressure (P2) between the initial support of the leading tunnel were distributed in the direction of vertical stratification, while the contact pressures (P1 and P2) of the lagging tunnel were different due to the excavation unloading of the leading tunnel. The maximum stress positions of the initial support of the leading tunnel and the lagging tunnel were located in the left arch waist and the vault, respectively. However, the maximum stress position of the secondary lining was generally located on the side wall. The research results presented herein can guide future tunnel construction projects.

Deep rock engineering is in a high pre-stressed state before excavation. In this research, a method to calculate the release of strain energy caused by excavation in pre-stressed rock is proposed. The normal stress release after excavation leads to a reduction in strain energy in rock specimens. The influence of excavation height and width on strain energy release is inconsistent under vertical loading. When the height of the hole is 1 mm, the strain energy release is large, and the increase in height of hole leads to a slow increase in the strain energy release. When the width of the hole is 1 mm, the strain energy release is very small, and the increase in the width of the hole leads to an increasingly faster release of strain energy. This strain energy release exponentially increases with the increase in the lateral pressure coefficient, showing a trend in the second power of the lateral pressure coefficient. Moreover, the tunnel failure caused by excavation under high stress is obtained by a numerical calculation. The failure modes of the deep tunnel model are strain rockbursts caused by tangential stress concentrations and spalling caused by normal stress release, which is also observed in the failure mode of the actual tunnel.