25 results about "Differential stress" patented technology

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.

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.

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.

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 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.

FIELD: underground mining in rocks.SUBSTANCE: method of mining a working in a rock mass exposed to tectonic stresses includes making a straight cut with the formation of a cutting cavity in the centre of the mine working, determining the direction of the greatest compressive stress in the massif and forming the mine working. If the greatest compressive stress is found in the horizontal transverse direction to the contour of the working, the cutting cavity is expanded by exploding pre-contour and contour blasthole charges in the horizontal transverse direction to the contour of the mine working, whereas as a result of the explosion, a dome-shaped part of the cavity of the mine working is formed due to the natural destruction of the rock.EFFECT: increase in the stability of the workings' boundary rocks.1 cl, 3 dwg

The utility model relates to steel support axial force adjusting device technical field especially relates to a kind of foundation pit steel support axial force adjusting device.Its technical scheme includes the pedestal applied to steel support and live joint, and the both sides of the pedestal are slidably installed with support rod, and the support rod is fixedly installed with jack, and it further includes the centering component installed on the pedestal, the centering component drives the middle part of pedestal to move to the position coinciding with steel support axis, and the pedestal is installed with the driving assembly of driving jack synchronous reverse movement.This utility model can prevent eccentric loading by the centering component, and avoid steel support tube wall under the combined action of superhigh local compressive stress and bending moment, partial bulging, wrinkling or even crushing at the position of maximum stress, prevent local instability to weaken the overall load-carrying capacity of steel support.

This invention provides a parametric design method for the crown clearance of marine gas turbine turbine pre-twisting blades, aiming to improve the fatigue damage resistance of marine gas turbine turbine blades and extend their service life. The parametric design method for the crown clearance of marine gas turbine turbine pre-twisting blades involves adjusting the interference and clearance parameters between the blade crowns, analyzing and evaluating the compressive stress and clearance calculation results corresponding to different parameters, and obtaining the optimal blade crown clearance value that meets the strength and vibration design requirements. The crown clearance value will serve as the basis for the design of the turbine pre-twisting blade crown structure. This invention can accurately simulate the interaction relationship between the blade crowns under operating conditions, optimize the design of the crown clearance value, and adjust the overall blade structural damping. It has significant engineering application value for improving the fatigue resistance and extending the service life of gas turbine pre-twisting blades.

The present application relates to a method for establishing a constitutive model of soil based on a prototype test and a test device used by the method, the method comprising the following steps: placing a sealed bag in a soil column test hole, injecting fluid into the sealed bag to load the soil, measuring the lateral displacement of the deep soil, calculating the yield cylindrical surface radius of the soil, the radial compressive stress at yield, and the principal stress state of the soil unit according to the circular hole expansion theory and the Lame equation, establishing the yield criterion, the subsequent yield surface, and the failure criterion, dividing the soil in the plastic deformation area into multiple concentric soil cylinders according to the graded loading, calculating the size and radial displacement of each soil cylinder from outside to inside, combining the test hole sidewall radial displacement test value, calculating the elastic parameters required by the incremental method in the elastic-plastic mechanics according to the test loading grade, establishing the constitutive model, assuming that the yield surface is a plane and the intermediate principal stress is ignored, degrading the yield criterion into the Mole-Coulomb criterion, and verifying the constitutive model through a prototype test.

This invention, entitled "A Method for Reducing Bias Stress in Tunnel Surrounding Rock," belongs to the field of tunnel engineering construction technology. The technical problem it aims to solve is that existing methods for addressing bias stress in tunnel surrounding rock primarily rely on reinforcement, which suffers from drawbacks such as high material consumption, significant construction difficulty, and long construction periods. These methods are ineffective in mitigating the problem of easily damaged tunnel support structures caused by unbalanced horizontal lateral pressure at tunnel entrances and exits. The key technical solution involves collecting engineering geological parameters and mechanical properties of the backfill concrete in the bias stress zone of the tunnel, calculating the total horizontal lateral pressure on the inside and outside of the tunnel, determining the bias stress risk, establishing a benchmark point, and peeling off the overburden layer and backfilling concrete on the outside of the tunnel. The peeling angle or concrete backfill elevation is iteratively adjusted until the difference in total horizontal lateral pressure between the inside and outside of the tunnel meets the engineering requirements.

The application discloses a super-large volume blank and a method for reducing the upsetting force of free forging, wherein the blank is designed as a drum shape with a large diameter at the upper and lower ends and a small diameter at the middle part, the three-way stress state of the metal during the upsetting is changed by using the drum shape structure, the axial compressive stress is converted into the radial tensile stress, the metal is guided to flow along the short axis direction under the minimum resistance law, and it is ensured that the deformation of the middle part of the blank after the outward drumming does not exceed the size of the two ends of the blank, so that the required upsetting force changes with the cross-sectional area of the middle part of the blank, and thus the upsetting of the super-large volume blank is performed with a smaller upsetting force. The blank is designed as the drum shape, so that the upsetting force of the free forging is not only reduced, but also the forming quality is improved.

The application discloses a floor water disaster prevention method based on mine pressure regulation and control, and belongs to the technical field of mine disaster prevention and control. The method is characterized in that: a large-diameter pressure relief borehole is constructed at the working face roadway side, the concentrated stress is transferred to the deep part, and a shallow coal body impedance area is formed; roof blasting is performed at the goaf side, the collapsed gangue is accumulated on the goaf floor to form a collapsed gangue impedance layer, and pressure stress is generated on the floor; the floor damage depth is dynamically monitored, the ratio of the floor aquiclude thickness to the safe aquiclude thickness is obtained, and the borehole spacing, the blasting hole spacing and the charge amount are adjusted in a graded progressive manner according to the 1.3 times and 1.1 times two-level threshold values. The application actively inhibits the downward expansion of the floor damage from the mechanical source, is simple and convenient to construct, has low cost, realizes parameter optimization through graded progressive regulation, and effectively reduces the floor water disaster risk.

This application relates to a support device and method for a mining roadway. First, a first support member and a second support member are placed on both sides of the mining roadway, with the first side conforming to one side of the surrounding rock and the second side conforming to the other side. The first and second straight sections extend to below the top of the surrounding rock. A fixing assembly initially fixes the first and second support members to the surrounding rock. A connecting assembly connects the first and second straight sections and applies a horizontal preload to the connecting assembly, causing the first and second support members to tend to move towards the middle of the mining roadway. The preload is transmitted to the top of the surrounding rock through the structure of the first and second support members, transforming into horizontal compressive stress on the top of the surrounding rock. This improves the stress state of the top of the surrounding rock, transforming the tensile stress area originally caused by roadway excavation into a compressive stress area, inhibiting the subsidence of the top of the surrounding rock, thereby improving the support effect of the support structure, reducing the maintenance of the mining roadway, and lowering the support cost.

The application relates to the field of bearing machining, and particularly discloses a machining process for a bearing outer ring, which comprises the following steps: S1. pretreatment; S2. surface nanocrystallization treatment; S3. rough grinding; S4. fine grinding; S5. superfinishing; and S6. cleaning. The surface nanocrystallization treatment is added before grinding, the raceway surface layer is subjected to severe plastic deformation through high-speed projectile impact, a gradient nanocrystalline structure layer which is gradually changed from the surface nanocrystalline to the coarse grain in the center is formed, the structure layer can improve the surface hardness and strength, reduce the subsequent grinding force and grinding heat, inhibit thermal damage and organizational phase change, deep stable residual compressive stress is introduced into the surface layer, the tensile stress generated during grinding is offset, the raceway is finally in a beneficial compressive stress state, and therefore, a high-hardness and low-damage high-quality surface layer is obtained, and the bearing matching precision, running stability and service reliability are improved.

The present application belongs to the technical field of bridge engineering, and relates to a stiffness compensation type composite beam system for inhibiting cracking in the negative bending moment area of a whole bridge, which comprises: a pre-deformation locking unit, which installs a stiffness compensator in the negative bending moment area of a steel beam and loads to generate a pre-deformation of upward arch, so as to lock elastic strain energy in the steel beam; a composite structure construction unit, which pre-buries a sensor above the steel beam and pours concrete, and forms a composite structure through a shear connector; a state monitoring and analysis unit, which collects multi-dimensional time-varying data to calculate the material state, compares an energy release window model to determine the application time; an energy controlled release unit, which controls the stiffness compensator to be unlocked to release energy to drive the steel beam to bend downward; and a pre-compression stress generation and verification unit, which utilizes the deformation of the whole structure to introduce a compressive stress in the bridge deck slab. The present application solves the technical problems of complex construction process of traditional prestressing technology and insufficient accuracy of prestress application timing control.

The utility model relates to underground pipe gallery construction technical field, and disclose a kind of prestressed locking mechanism of block type U-shaped pipe gallery core mould, the connecting assembly is composed of fixed cylinder, slider, limit rod, pull rod, spring, the fixed cylinder is fixedly installed in the top of mounting plate, the slider is slidably installed in the inside of fixed cylinder.The prestressed locking mechanism of block type U-shaped pipe gallery core mould is set up steel cable and accurate control tensioning stress in the key stress position of U-shaped module, more effective prestress can be applied to it, which can not only significantly improve the anti-deformation ability of U-shaped module as a whole, when the non-uniform settlement of local gene, load fluctuation produces upward reaction, the compressive stress previously established in the interior of U-shaped module can also be efficiently offset, greatly reduce the possibility of U-shaped module cracking due to tension, thereby avoiding the structural durability decline, leakage and other problems caused by crack, ensure that U-shaped module maintains stable and reliable working condition in long-term use.

This invention relates to the field of geostress inversion technology, and discloses a method, apparatus, equipment, and medium for geostress field inversion based on sparse measuring points. This invention employs multiple machine learning models to establish a nonlinear mapping between the stress response of measuring points and boundary parameters. By representing the initial geostress field as a parameterized boundary form of lateral pressure coefficient and shear stress components, it avoids the problem of introducing abnormal stress zones easily by traditional displacement or stress boundary loading. By introducing a physical consistency correction mechanism that includes the burial depth growth trend and compressive stress dominance constraints, it effectively suppresses abnormal tensile stress zones that may appear in the inversion results, solving the problem that existing methods may have correct fitting but are physically unreasonable. This invention, through the organic combination of parameterized boundary characterization, intelligent inversion modeling, and physical law constraint correction, significantly improves the stability, physical rationality, and engineering applicability of geostress field inversion while ensuring the accuracy of measuring point matching.