117 results about "Differential stress" patented technology

The invention relates to a stress analysis method and system based on a small and medium span bridge steel-concrete composite structure, and belongs to the technical field of stress analysis, and the method comprises the following steps: S1, building a finite element parameterized model of a steel-concrete composite bridge; s2, constructing a slippage effect model of a steel-concrete interface based on the constitutive relationship of the steel-concrete composite bridge; s3, applying a moving load working condition, and dividing a load position of the steel-concrete composite bridge through a dynamic grid; s4, solving and correcting the structural stress of the steel-concrete composite bridge; s5, key section stress distribution of the steel-concrete composite bridge is output so as to identify the maximum tension and compression stress area; the method has the beneficial effects that the dynamic change of the load action can be accurately reflected in the model so as to reflect the stress state of the bridge under the actual traffic load; and an accurate structural stress solution is gradually approximated, and a reliable stress analysis result is obtained by comprehensively considering material characteristics, structural geometrical shapes and load distribution factors.

The application discloses a composite material structure bushing reinforcing method based on electromagnetic loading, which uses electromagnetic loading to complete the bushing reinforcement of the composite material structure, and obvious beneficial effects are obtained compared with traditional methods. The method proposes a process parameter calculation method for the reinforcement process of the structure to solve the problem that existing devices and methods cannot be applied to the bushing reinforcement of the composite material structure. The radial compressive stress around the hole is obtained through the Lame formula and the elastic stress-strain relationship of the composite material, and then the total resistance of dynamic extrusion friction in the reinforcement process is obtained through the Coulomb friction theory, and the process parameters are determined in combination with the mathematical model of the electromagnetic force. The application can realize the calculation of the reinforcement process parameters of the composite material bushing with different structures and sizes, and is used for guiding the reinforcement of the dynamic cold extrusion composite material bushing structure.

Novel hybrid tunnel boring methods, systems, and apparatuses are described. Example hybrid methods integrate (a) thermal processing, e.g., preconditioning and / or thermal spallation (which may be used as pre-treatment), and (b) mechanical processing while boring tunnels in rock and other formations. Thermal processing and mechanical processing may be used alternatively or simultaneously. For example, the preconditioning may use thermal energy to induce thermal shock and weaken the rock (e.g., cause expansion stress, micro-fractures, thermal spallation, etc.). This preconditioning changes the relevant properties of the rock relative to the additional (e.g., mechanical) excavation, including, among other things, effective compressive stress, abrasion properties, and hardness. This preconditioned rock can therefore be efficiently removed using mechanical drilling tools, resulting in, for example, faster boring speeds, reduced tool wear, enhanced precision, and longer deployment lengths (e.g., in comparison to conventional TBM and especially MTBM approaches).

Novel hybrid tunnel boring methods, systems, and apparatuses are described. Example hybrid methods integrate (a) thermal processing, e.g., preconditioning and / or thermal spallation (which may be used as pre-treatment), and (b) mechanical processing while boring tunnels in rock and other formations. Thermal processing and mechanical processing may be used alternatively or simultaneously. For example, the preconditioning may use thermal energy to induce thermal shock and weaken the rock (e.g., cause expansion stress, micro-fractures, thermal spallation, etc.). This preconditioning changes the relevant properties of the rock relative to the additional (e.g., mechanical) excavation, including, among other things, effective compressive stress, abrasion properties, and hardness. This preconditioned rock can therefore be efficiently removed using mechanical drilling tools, resulting in, for example, faster boring speeds, reduced tool wear, enhanced precision, and longer deployment lengths (e.g., in comparison to conventional TBM and especially MTBM approaches).

The invention discloses a cut blasting method, and relates to the technical field of tunneling, a first cut hole extends from a rock mass area related to a current excavation cycle to a rock mass area related to a next excavation cycle, after a first excavation cycle is completed, a sub-surface has a temporary cavity in each subsequent excavation cycle process, and a second cut hole extends from the rock mass area related to the next excavation cycle to the rock mass area related to the next excavation cycle. The crustal stress on the boundary of the temporary cavity is released to cause the crustal stress redistribution of the rock mass in the region involved in the next excavation cycle, so that the temporary cavity forms a pressure stress concentration region in the minimum principal stress direction, and the strength of the rock mass in the region involved in the next excavation cycle is reduced; the temporary cavity and the rock mass damage area can be used for assisting in completing rock breaking excavation in the subsequent excavation cycle, and the amount of explosives needed in the whole excavation process is reduced; and the blasting parameters of the slotting hole group required by the next excavation cycle can be adjusted in a targeted manner according to the geometric parameters, so that the problem that the slotting area is formed too large or too small due to blind reduction of the explosive quantity is solved, and the forming quality of the slotting area is ensured.

The invention relates to the technical field of coated steel plate production, in particular to a high-straightness coated steel plate and a production method thereof. During production, the following processes are controlled: 1) finishing, namely determining finishing inlet tension T1, finishing outlet tension T2 and finishing rolling force F according to the thickness h and yield strength sigma s of strip steel, and ensuring that a tensile stress value formed by a tension roller is greater than a pressure stress value formed by the rolling force; and 2) coiling: adopting double coiling mechanisms to ensure that the strip steel does not generate longitudinal warping when the strip steel passes through a second turning roller and is coiled. Based on the forming mechanism of the plate shape defect, stable control over the plate shape of the coated steel plate finished product is achieved by improving the finishing parameter adaptation degree and improving the coiling equipment and technology, and great significance is achieved for improving the straightness of the coated steel plate finished product and improving the production efficiency and product competitiveness of the coated steel plate.

The invention provides a convenient, practical and high-precision method for measuring the uniform load and dynamic load coefficients of the planetary transmission system and a corresponding strain bridge sensor design method, and the method has the advantages of superposition of tension and compression stress, temperature compensation, avoidance of tedious calibration and the like. And a technical approach is provided for solving the actual measurement of the uniform load and dynamic load performance of the planetary transmission system.

The invention discloses a coal body pressure relief drill hole arrangement method based on a working face crustal stress direction, which comprises the following steps: arranging a micro-seismic monitoring system on a working face, and collecting micro-seismic event data of the working face in real time; when the energy of a certain micro-seismic event exceeds a preset energy threshold value, short-term stress field inversion is triggered, a stress field near a working face is inverted, and the directions of the maximum horizontal pressure stress and the minimum vertical tensile stress are determined; the arrangement direction of drill holes is determined according to the direction of the maximum horizontal pressure stress; a plurality of drill holes are constructed according to the arrangement direction of the drill holes, and pressure relief is conducted on the coal body; the stress change of the working face is monitored in real time through the micro-seismic monitoring system, and the arrangement scheme of the drill holes is dynamically adjusted according to the monitoring result. According to the method, the earthquake activity risk can be remarkably reduced, the pressure relief effect is improved, the coal rock dynamic disaster prevention capacity is improved, the stress field inversion precision and efficiency are improved, the coal mining safety and efficiency are enhanced, and meanwhile resource waste and environmental influence can be reduced.

This invention provides a method, apparatus, and equipment for evaluating the progressive failure mechanical properties of concrete tunnels in cold regions, relating to the field of engineering mechanics. The method includes: obtaining initial damage parameters and material parameters of a standard sample of the concrete structure to be evaluated; calculating the initial damage value of the concrete based on the initial damage parameters; determining the relationship between the damage value of the concrete after ice fills cracks and the freezing temperature based on the relationship between the initial damage value, material parameters, and the elastic modulus of ice. It also involves calculating ice pressure based on the initial damage parameters, material parameters, and ice-related parameters; determining the correspondence between compressive stress and compressive strain of the concrete at different freezing temperatures based on the relationship between the damage value of the concrete after ice fills cracks and the ice pressure; and evaluating the progressive failure mechanical properties of the concrete based on the relationship between compressive stress and compressive strain. This invention enables accurate prediction and evaluation of the progressive failure process of concrete.

The present invention provides a method for evaluating the dynamic shear capacity of a ram blowout preventer, which relates to the technical field of petroleum exploration and development. The dynamic shear stress calculation step adopts a three-parameter generalized strength criterion under the coupling of tension, compression, and shear according to the stress state of the ram blowout preventer during the shearing process, and analyzes and derives the stress distribution of the drill pipe under the dynamic working condition to obtain a theoretical formula for stress calculation of the drill pipe; the shear force estimation step uses the equivalent relationship between the ram shear and compressive stresses and the material yield criterion theory to obtain the shear resultant force F; the external force on the shear ram in its movement direction is comprehensively considered to calculate the ram comprehensive shear force F. max The evaluation method of the present invention introduces a three-parameter generalized strength criterion under the coupled effects of tension, compression, and shear, and proposes a method for constructing a theoretical model for calculating dynamic drill pipe shear stress, which has high applicability. The present invention also relates to a dynamic shear capacity evaluation device for a gate blowout preventer, which can be tested and inspected.

The present application belongs to the technical field of structural strength analysis, and particularly relates to a strength analysis method for a variable gradient composite material wall panel, the strength analysis method comprising: solving the shear stress and compression stress of the variable gradient composite material wall panel based on the external load and structural parameters of the variable gradient composite material wall panel; calculating the allowable shear stress, allowable axial compression stress, and allowable bending stress based on the structural parameters; calculating the safety margin through the shear stress, the compression stress, the allowable shear stress, the allowable axial compression stress, and the allowable bending stress; the iterative safety margin is 0; and the stability strength design of the trapezoidal composite material wall panel with a variable gradient of the rudder surface can be performed, and finally the lightest wall panel structural parameters that meet the constraint conditions are obtained.

Novel hybrid tunnel boring methods, systems, and apparatuses are described. Example hybrid methods integrate (a) thermal processing, e.g., preconditioning and / or thermal spallation (which may be used as pre-treatment), and (b) mechanical processing while boring tunnels in rock and other formations. Thermal processing and mechanical processing may be used alternatively or simultaneously. For example, the preconditioning may use thermal energy to induce thermal shock and weaken the rock (e.g., cause expansion stress, micro-fractures, thermal spallation, etc.). This preconditioning changes the relevant properties of the rock relative to the additional (e.g., mechanical) excavation, including, among other things, effective compressive stress, abrasion properties, and hardness. This preconditioned rock can therefore be efficiently removed using mechanical drilling tools, resulting in, for example, faster boring speeds, reduced tool wear, enhanced precision, and longer deployment lengths (e.g., in comparison to conventional TBM and especially MTBM approaches).

A connect fitting includes a first connector, a second connector, and at least one groove. The first connector is a hollow structure and has a first connecting end and a first free end. The second connector is a hollow structure and has a second connecting end and a second free end. The first connecting end and the second connecting end are detachably engaged with each other to allow communication between the first connector and the second connector. At least one groove is recessed in at least one of an inner wall of the first free end and an inner wall of the second connecting end. When a hydraulic pipe is connected to the first free end or the second free end, the groove can release compressive stress exerted on the hydraulic pipe to prevent the hydraulic pipe from deformation, cracking, or damage.

The utility model provides a rock debris sampler for geological prospecting, and relates to the field of geological prospecting, the rock debris sampler comprises a sampler body, the sampler body is movably sleeved with a connecting sleeve, the connecting sleeve is fixedly sleeved with a fixing ring, and the surface of the fixing ring is fixedly connected with eight fixing plates; a supporting shaft is rotationally connected between every two adjacent fixing plates, the supporting shafts are fixedly sleeved with supporting legs, and torsional springs are fixedly connected between the supporting legs and the fixing plates. Through cooperation of the supporting legs, the fixed rings, the sliding rings, the first connecting pieces, the second connecting pieces, the transverse plates and other structures, a plurality of triangular stabilizing units are formed together, loads such as vibration and impact generated when the sampler works are converted into tension and compression stress in the transverse plates from concentrated stress at the joints of the supporting legs, and the stability of the sampler is improved. Therefore, the stress concentration phenomenon of connecting points of the supporting legs is effectively avoided, and the risk of fatigue fracture of welding points is effectively reduced.

The invention belongs to the technical field of house construction frames, and discloses an opposite penetrating type support based on multilayer pipelines, which comprises a support mechanism and a bearing mechanism, a support space is arranged outside the support mechanism and is used for assembling a device, and the bearing mechanism is positioned outside the support mechanism and is used for supporting the pipelines. The adjusting mechanism is installed outside the bearing mechanism and used for adjusting the pipeline, the weight of the pipeline enables the two oval sliding rod sleeves to get close to each other, at the moment, in the movement process of the oval sliding rod sleeves, the flexible arc plates push and extrude the pipeline, concentrated loads at the bottom of the pipeline are converted into lateral dispersion force, and the pipeline can be adjusted. Local pressure stress is reduced, the situation that the gravity of the pipeline is accumulated at the bottom of the oval sliding rod sleeve, so that the bottom of the pipeline is locally crushed is prevented, the phenomenon that the bottom of the pipeline is sunken is reduced, and the supporting and protecting effect of the pipeline is improved.

The invention relates to the technical field of engineering support of metal mine high-stress stratums, in particular to a metal mine high-stress stratum ultra-deep vertical shaft oval lining support structure and method.The metal mine high-stress stratum ultra-deep vertical shaft oval lining support structure comprises an oval vertical shaft wall and a composite support system, and the composite support system comprises an initial flexible support, a shaft outer lining and a shaft inner circular lining; the long axis of the oval well wall is arranged in the maximum horizontal principal stress direction of primary rock stress. A traditional round shaft is changed into an oval shaft, the long axis extending direction of the oval shaft is kept consistent with the maximum principal stress direction, the tensile stress area is effectively expanded to the two sides of the long axis, the surrounding rock pressure is effectively released, after optimization, stress distribution is remarkably improved, the maximum principal stress is dominated by pressure stress, and the stress distribution is reduced. Compared with a traditional circular structure, a more reasonable stress state is realized; the minimum principal stress is also greatly reduced after filling, and the overall stress performance is remarkably improved.

The present application relates to a kind of rock-socketed foundation bearing capacity compensation design method considering rock mass constraint, comprising: establishing rock-socketed foundation calculation model, determine its consolidation boundary condition in rock layer;Calculate the horizontal soil resistance of triangle distribution produced when foundation rotates;Solve the resisting moment of horizontal rock resistance to base center;The deformation of base is decomposed into integral subsidence and rotating component;Determine the calculation formula of base zero stress point position, and establish base vertical pressure distribution model;Establish the overall balance equation group, and solve the foundation rotation angle and zero stress point position by iteration calculation;Calculate the maximum compressive stress of base and evaluate the bearing capacity compensation effect;Finally, section internal force analysis and reinforcement design are carried out.The present application provides additional resisting moment by quantifying rock mass constraint, effectively reduces the maximum compressive stress of base, provides theoretical basis and technical support for improving foundation bearing capacity and optimizing foundation size, and is especially suitable for rock-socketed foundation design in high intensity seismic region.

The invention provides a forming process method of an aircraft panel, which comprises the following steps of: firstly, carrying out finite element joint analogue simulation on stretch forming and shot peening strengthening processes before actual operation is started, and determining optimal stretch and low-energy shot peening parameters; after manufacturing is started, a single profile blank is prepared through an integrated extrusion and quenching combined technology, and the defects that in a traditional technology, the rigidity of a multi-component riveting plate is low, and the material utilization rate is low are overcome; in the stretching process, residual tensile stress is introduced into the core part of the wallboard through pre-stretching, and the residual tensile stress and surface residual compressive stress generated by subsequent shot blasting can form a synergistic strengthening effect, so that the fatigue life is prolonged; and shot blasting adopts a low-energy mode, so that various defects caused by traditional high-energy spraying can be effectively avoided while the surface appearance and the pressure stress precision are ensured. The invention also provides targeted process optimization for ribbed and unribbed wallboards, so that not only is the dependence on complex clamping equipment eliminated, but also the deformation risk caused by clamping stress can be effectively avoided.

The invention provides a discrete ballastless track tension-compression fatigue damage rapid calculation method, which comprises the following steps of: uniformly measuring a complex stress state and a simple stress state through a damage energy release rate, and decomposing tension-compression effective stress by utilizing a fourth-order projection tensor, so that the tension-compression effective stress value is equivalent to a uniaxial tension-compression stress value under a uniaxial loading condition; constructing a hyperbolic function with a natural constant as a base and a damage variable as an index on the basis of the damage energy release rate and in combination with three-stage damage characteristics of high-cycle fatigue of the material; carrying out integration on fatigue loading times through tension and compression damage, and deducing to obtain a discrete transcendental differential function of the damage related to the loading times; function variables are defined, an initial value is set, an iteration format is established, the discrete transcendental differential function is solved through a numerical integration method, and a calculation result graph is drawn. The model is simplified, and the calculation efficiency is improved; a high-order tensor stress updating algorithm does not need to be constructed, redundant calculation is reduced, and the data processing efficiency and the calculation speed during parameter analysis are greatly improved.

The present invention relates to the technical field of building engineering wall construction, and in particular to a method for constructing anti-cracking walls based on gradient combination. The method first calculates the limiting expansion index parameter ε of the intermediate wall. e , and based on this, the mix ratio was obtained. The expansive concrete mix ratio was then verified and optimized. Based on the gradient combination of anti-cracking wall dimensions, the structures of various parts of the overall anti-cracking wall were designed, and the gradient combination of anti-cracking wall casting construction was carried out, including casting the intermediate wall within 5-25 days after the reaction pier casting was completed. Finally, the overall anti-cracking wall curing construction was carried out. When the later-cast intermediate wall expanded outward, it encountered the reaction pier and was squeezed, thereby pre-establishing pre-compressive stress. This part of the pre-compressive stress can offset the tensile stress caused by the later shrinkage and temperature deformation of the concrete, effectively preventing the occurrence of structural cracks.

This invention discloses a parameterized analysis method for the structural dimensions of a high-strength cold-cast anchor, comprising the following steps: S1, determining the strength and diameter of the parallel steel wire according to actual requirements; S2, calculating the minimum cone length of the anchor cup to obtain the selection range of the anchor cup cone length, and initially selecting the anchor cup cone length; S3, selecting the inner diameter and cone angle of the rear cone of the anchor cup, and calculating the inner diameter of the front cone; S4, calculating the circumferential surface area of ​​the cone of the cold-cast filler; S5, calculating the compressive stress of the cone of the cold-cast filler; S6, determining σ... c Is it less than [σ]? c If yes, proceed to step S7; otherwise, remove any one of the currently selected anchor cup cone length, rear end cone inner diameter, or cone angle from the selection range, and proceed to step S2; S7: Select the anchor cup outer diameter, calculate the anchor cup average inner diameter and anchor cup circumferential stress; S8: Determine σ r Is it less than [σ]? r If yes, proceed to step S10; otherwise, proceed to step S9; S9: Adjust the outer diameter of the anchor cup and proceed to step S7; S10: Complete the dimensional analysis of the high-strength cold-cast structure.

The application provides a design method of a U-shaped steel clamp for an aviation wheel, and belongs to the technical field of aviation brake wheels. The method determines the compressive stress of the steel clamp according to the normal force transmitted by the guide rail of the aviation wheel to the steel clamp and the contact area between the guide rail of the aviation wheel and the steel clamp. When the compressive stress of the steel clamp meets the requirements, the dangerous shear cross-sectional area of the steel clamp is determined. Then, the maximum shear stress of the steel clamp is determined according to the dangerous shear cross-sectional area of the steel clamp and the determined normal force. When the shear stress of the steel clamp meets the requirements, the bending modulus of the cross section of the steel clamp is determined. After that, the maximum bending moment borne by the steel clamp is determined according to the determined normal force. Finally, the maximum bending stress of the steel clamp is determined according to the determined bending modulus of the cross section and the maximum bending moment, and whether the maximum bending stress of the steel clamp meets the requirements is determined. The method solves the problem that the U-shaped steel clamp is prone to fracture, resulting in loss of friction torque and functional failure of the rotor assembly.

This invention discloses a staged pressurized hydraulic precision push-forming device for steel pipe ends, which relates to the field of metal pipe processing technology. This staged pressurized hydraulic precision push-forming device for steel pipe ends decomposes the processing of irregularly shaped flanged ends into two independent stages: low-pressure pre-forming and high-pressure finishing. In the pre-forming stage, applying a lower initial pressure guides the material to achieve stable plastic flow, effectively controlling the metal flow rate and avoiding material accumulation and circumferential compressive stress instability at the pipe edge caused by single high-pressure forming. This suppresses the generation of flange burrs and wrinkling defects from the process source. In the finishing stage, switching to a high-pressure shaping component and applying a second-level set high pressure ensures that the pre-shaped contour fully conforms and eliminates internal residual elastic strain, significantly improving the problems of unexpected springback and secondary deformation after pressure relief and ensuring the contour accuracy of the irregularly shaped end.

This invention discloses a stability analysis method for the bearing arch of a large-span tunnel based on compressive and tensile safety factors, belonging to the field of tunnel and underground engineering construction data analysis technology. The method includes the following steps: obtaining the tunnel geometry, surrounding rock mechanical strength, ground stress, and support parameters; simplifying the bearing arch formed by anchor spraying reinforcement into an arched beam elastically fixed to the sidewalls at both ends; determining the plastic loosening zone of the roof slab through numerical simulation, and using its self-weight as the main vertical load; calculating the internal forces and edge normal stresses of key sections of the bearing arch using structural mechanics, and classifying them into compressive and tensile stresses accordingly; calculating the compressive and tensile safety factors of each section based on the natural strength parameters of the surrounding rock, and using the minimum value as a quantitative index for evaluating the overall stability of the bearing arch. This invention establishes a quantitative mechanical model of the bearing arch, realizing accurate and convenient assessment of the safety of the anchor spraying support structure of the roof slab of ultra-large span tunnels.

The invention belongs to the technical field of material mechanics, particularly relates to a material mechanical property detection device and method based on machine vision, and provides the following scheme aiming at the problem that an underwater test in the prior art cannot simulate the pressure stress change of a material: the device comprises a detection table which is provided with a downward opening and is integrally of a groove-shaped structure, a mounting circular hole is formed in the upper surface, close to one end, of the detection table, a pressure-resistant detection cylinder is welded and fixed in the mounting circular hole, and a bottom supporting plate is fixed to the bottom of the pressure-resistant detection cylinder. When the material mechanical property of the machine vision module needs to be detected, the machine vision module only needs to be fixed to the corresponding position of the bottom of the bottom supporting plate, then the sealing gland covers the machine vision module and is filled with saline water, finally, the high-sealing piston is slowly pushed downwards, pressure can be generated on the surface material of the machine vision module, and the mechanical property of the machine vision module is detected. And then the machine vision module is electrified to observe whether the quality of an image fed back by the machine vision module is normal or not, so that the mechanical property detection function of the material is further realized.

The invention provides a forging method and system for improving the external dimension precision of a forge piece, belongs to the technical field of metal plastic forming, and solves the problems that a transition R corner of a stepped shaft made of a difficult-to-deform material is easy to crack and low in precision. The method comprises the following steps: a pre-forming step: placing an independent pre-forming tool with a target R angle profile on a bar, applying force to the pre-forming tool, rotating the bar at the same time, and pressing an annular groove mark on the surface of the bar; and a final forging step: removing the pre-forming tool, carrying out forging and pressing diameter reduction on the shaft section on one side of the groove mark, and rotating the bar material to form the stepped shaft. The deformation area is in a three-direction pressure stress state through preforming, the material plasticity is improved, cracks are restrained, the R angle precision is guaranteed through the preforming tool, and therefore the yield and reliability are improved.

The invention discloses a large-span tunnel bearing arch stability analysis method based on compressive and tensile safety coefficients, and relates to the technical field of tunnel and underground engineering construction data analysis, and the method comprises the following steps: obtaining cavern geometry, surrounding rock mechanical strength, ground stress and support parameters; a bearing arch formed by anchoring and shotcreting reinforcement is simplified into an arched beam with the two ends elastically and fixedly connected to the side walls; determining a plastic loosening area of the top plate through numerical simulation, and taking the self weight as a main vertical load; calculating key section internal force and edge normal stress of the bearing arch by using structural mechanics, and dividing the internal force and the edge normal stress into pressure stress and tensile stress; based on the natural strength parameters of the surrounding rock, the compression-resistant and tensile safety coefficients of all the sections are calculated, and the minimum value is used as a quantitative index for evaluating the overall stability of the bearing arch. According to the method, the quantitative mechanical model of the bearing arch is established, and the safety of the ultra-large-span tunnel roof anchor-shotcrete supporting structure is accurately and conveniently evaluated.

The present application belongs to the technical field of geotechnical engineering support, and discloses a self-drilling anchor rod supporting system and method based on adjustable delayed expansion slurry and dynamic pressure splitting grouting cooperation. The present application forms a coated calcium oxide expanding agent by using a specific material, and delays the expansion burst time to after the slurry has initial strength and the orifice is locked. The limited expansion force not only compensates for the condensation of the cement base, but also is converted into a powerful radial compressive stress, which realizes "first extrusion and compaction, then cementation and solidification" for the broken surrounding rock, and greatly improves the overall stability of the composite bearing body. The dynamic pressure splitting grouting process of introducing a specific frequency pressure is used to open the crack tip and communicate other cracks by using alternating pressure. At the same time, the hydrophobic coating of the coated calcium oxide expanding agent physically isolates the core expansion component during the grouting stage, avoiding the viscosity surge and invalid expansion caused by the premature hydration of conventional expanding agents. The two cooperate to ensure the excellent permeability and uniform diffusion capacity of the slurry in the deep micro blind end cracks.

The invention provides a method for determining the detonation speed of an explosive used for tunnel caving blasting by considering the influence of ground stress, and belongs to the technical field of blasting engineering and rock mass mechanics. Comprising the steps of obtaining rock mass mechanical parameters, blasting parameters and crustal stress data; establishing a stress analysis model based on ground stress and a blasting design drawing; establishing a crustal stress redistribution model caused by a cut cavity in the model, calculating radial pressure stress generated by crustal stress redistribution among the caving holes, and drawing a polar coordinate graph; establishing a collapse inter-hole explosion stress superposition model, and calculating circumferential tensile stress generated by explosion at the central points of the two holes; and based on the dynamic tensile strength and stress state of the rock, establishing a strength criterion for forming the inter-hole through crack, and deducing and solving the minimum explosive detonation speed required by the criterion. The blasting joint forming quality is effectively improved, back break is controlled, surrounding rock damage is reduced, and the safety, economical efficiency and reliability of blasting engineering are improved.

This invention discloses a high-load-bearing backing bearing with a multi-layered composite wall thickness outer ring. The bearing's dynamic blocking transition layer is composed of polyhedral rigid microparticles and a viscoplastic matrix, with the microparticle volume fraction limited within a critical blocking threshold range. Under quasi-static radial heavy loads, the microparticles are in a blocked state, forming a rigid force chain that transmits hydrostatic stress. Under high-frequency transverse shear stress wave excitation, the matrix undergoes transient superplastic rheology, and the force chain enters a locally unblocked state, resulting in micro-rheology and a sudden drop in transverse shear stiffness. Based on the orthogonal decoupling of stress states and the dual-state phase transition characteristics, this invention actively disrupts the subsurface standing wave resonance condition, resolving the contradiction between macroscopic compressive strength and microscopic dissipation. This effectively suppresses deep peeling failure under high-speed, heavy-load conditions, and its material selection and process design fully embody the energy-saving and high-efficiency concept of green manufacturing.