38 results about "Out stress" patented technology

The invention provides a finite element-based method for estimating pulling-out ultimate bearing capacity of a grouting screw anchor in gravelly soil, and relates to the technical field of civil structure engineering.A three-dimensional finite element model containing the grouting screw anchor and surrounding gravelly soil is established, model parameters cover the structure and material characteristics of the grouting screw anchor, and the grouting screw anchor and the surrounding gravelly soil are subjected to finite element modeling; a coordinate axis is established with the center of the anchor bottom as an original point for grid division, a stress concentration area is analyzed, principal stress is calculated to serve as critical bearing stress, vertical pull-out loads are applied step by step through a grouting pull-out test, a pull-out stress influence area is determined, soil stress of the area is analyzed, and soil binding power and friction force are calculated. And a grouting coefficient and a rock crack coefficient are generated, soil parameters are corrected, and the ultimate pulling bearing capacity of the grouting screw anchor is comprehensively obtained. According to the method, the pulling ultimate bearing capacity of the grouting screw anchor is accurately evaluated by establishing the three-dimensional finite element model and the graded loading experiment.

The invention relates to a large-scale high-temperature alloy blank casting method capable of controlling the casting size, and belongs to the technical field of high-temperature alloy casting. Measuring a temperature curve of the sand mold after the high-temperature alloy is poured; a process model is created, simulation software is used for carrying out stress deformation simulation, a part model of the casting is created, the simulation result of the part model and the simulation result of the process model are compared, the reduced scale, correction and the machining amount are adjusted in real time, and the process model is obtained; manufacturing a process pattern according to the process model, and producing a sand mold by utilizing the process pattern; creating a sand core model, inputting sand mold temperature curve parameters into simulation software, carrying out sand core deformation stress simulation, measuring sand core deformation stress, and manufacturing a core box according to the sand core model; a core bar is manufactured according to the design, the manufactured core bar is placed in a core box, and a sand core is manufactured; demolding the sand core; combining the sand core with the sand mold to obtain a casting cavity; and molten steel is poured into a casting cavity, and a casting blank is formed after cooling and solidification.

The invention relates to the technical field of arc shaped energy-gathered blasting parameter design, and provides an arc shaped energy-gathered blasting parameter design method under a complex crustal stress condition, which comprises the following steps: establishing a double-hole blasting three-dimensional model comprising a rock mass, an arc explosive, an energy-gathered pipe and coupled air, applying a crustal stress boundary condition and carrying out stress initialization; setting material model parameters based on the test data; performing fluid-structure interaction dynamic response numerical simulation on the model by adopting LS-DYNA to obtain stress and strain response caused by blasting; and establishing evaluation indexes based on tensile stress, compressive stress and through crack formation, carrying out sensitivity analysis and optimization adjustment on key blasting parameters such as blast hole spacing, delayed detonation time, explosive loading amount and coupling coefficient, and finally determining an optimal blasting parameter combination in different stress states. The method can effectively meet the blasting operation requirement under the complex ground stress condition, the presplitting quality and the rock mass stability are remarkably improved, and the method has wide engineering application prospects.

The invention discloses an underwater block stone cushion vibration density parameter control method and system based on vibration settlement, and the method comprises the steps: S100, building a block stone cushion vibration density vibration system based on a spring-damping-concentrated mass theory; s200, carrying out stress analysis on a vibration system of the block stone cushion layer vibration density to obtain an overall kinetic equation of a vibration device and the block stone to be vibrated; s300, combining the overall kinetic equation in the step S200 with the displacement of the vibration system to obtain a third-order differential equation about elastic deformation; s400, combining the overall kinetic equation in the step S200 with a soil body reaction force to obtain a second-order differential equation about elastic deformation; s500, an iterative algorithm based on the Runge-Kutta method is compiled, the differential equation is solved, and a numerical solution of the differential equation is obtained; and S600, obtaining an output parameter in the vibration process, and adjusting an input value of the vibration system according to the output parameter. And the elasticity, damping and plastic deformation of the block stone cushion layer in the vibration compaction process are comprehensively considered.

The invention provides a mechanical property analysis method for a shield tunnel reinforced concrete segment. The method comprises the following steps: step 1, constructing an aggregate three-dimensional model database; 2, constructing a first aggregate accumulation model based on the aggregate three-dimensional model; 3, establishing a three-dimensional model of each part forming the concrete segment; step 4, constructing a three-dimensional model of the heterogeneous reinforced concrete duct piece; 5, constructing a stratum three-dimensional model and a grouting layer three-dimensional model; step 6, constructing a heterogeneous shield tunnel reinforced concrete segment three-dimensional model; and 7, carrying out stress analysis on the heterogeneous shield tunnel reinforced concrete segment three-dimensional model. According to the invention, the random distribution characteristics of the aggregate in the concrete and the interaction relationship between the aggregate and the concrete, between the reinforcing steel bar and the concrete and between the grouting layer can be reflected more truly, and the heterogeneity and complexity of the concrete microstructure can be captured more accurately, so that the mesomechanical characteristics of the duct piece in the stress process can be revealed more comprehensively.

The invention belongs to the technical field of water conservancy projects, and discloses an extra-high arch dam bank slope dam section concrete first bin high lift layer construction method which comprises the following steps: step 1, determining dam concrete construction layering, step 2, establishing a template support model, step 3, carrying out stress checking calculation and the like. According to the extra-high arch dam bank slope dam section concrete first bin high lift layer construction method, PKPM structural calculation software is combined with the structural form of a dam, the distance from an upstream excavation face is combined, a model is established for structural stress and stability analysis, high lift layer construction is achieved, the highest lift layer height is large, multi-bin parallel one-time pouring is achieved, the pressure of a standby bin is relieved, and the construction efficiency is improved. The construction efficiency is improved. According to the ultrahigh arch dam bank slope dam section concrete first bin high rising layer construction method, the pouring height and quality of each layer can be effectively controlled, the uniformity and compactness of concrete are ensured, and the construction precision of the whole structure is improved.

The invention provides a rubber bolt composite coaxial connection design method, a connection device and a preparation method of an FRP rib, and relates to the field of reinforcing members in building structures, the design method comprises the following steps: based on a cantilever beam structure of a jamming bolt bearing the shear stress of a bonding medium, obtaining the jamming resistance of the jamming bolt; the bearing capacity of the bonding medium is obtained based on a double-broken-line model; carrying out stress analysis on the FRP rib, the bonding medium and the sleeve to obtain total bearing capacity Fj; and obtaining structural design parameters of the sleeve, the jamming bolt and the bonding medium according to connection bearing critical conditions and mechanical parameters of the FRP rib. Through the combined action of the constraint force of the sleeve, the binding force of the binding medium and the blocking force of the blocking bolt, the coaxial connection deviation value of the FRP rib is dynamically compensated, so that the problems that the FRP rib is easy to slip, insufficient in centering degree, remarkable in stress concentration and performance degradation caused by long-term creep or shrinkage in the connection process are solved, and the service life of the FRP rib is prolonged. And high redundancy and high reliability are provided through multiple force transmission paths and an active compensation mechanism.

The application discloses a kind of prediction model establishment methods of exhaust heat end low cycle fatigue life, comprising the following steps: according to engine at different power, set different exhaust heat end model thermal boundary condition;According to each boundary condition respectively to exhaust heat end model is carried out stress field analysis, obtains the strain table of the maximum equivalent plastic strain increment of exhaust heat end and the temperature table of the maximum equivalent plastic strain increment corresponding node;According to the maximum equivalent plastic strain increment of exhaust heat end determines exhaust heat end life check component;Based on the temperature value in temperature table respectively to check component carries out high temperature tensile test and cold thermal shock cycle test, obtains the static tensile table of the material of life check component under corresponding temperature and test life table;According to static tensile table, test life table and strain table determine the prediction model of exhaust heat end, to predict the fatigue life of exhaust heat end, it is convenient to set up reasonably for the overhaul and replacement cycle of exhaust heat end.

The application discloses a kind of hot-rolled high-strength steel and its plate shape control and optimization method, belong to the production method field of hot-rolled high-strength steel.The tensile strength grade of hot-rolled high-strength steel is 500-700MPa, and the thickness is 2.0-12.0mm;Plate shape control and optimization method is obtained by slab heating, rough rolling, finish rolling, laminar cooling, coiling production process to get steel coil, send steel coil into bell type annealing furnace to carry out stress relief annealing treatment to obtain hot-rolled high-strength steel with good plate shape, annealing process is: from room temperature to 450-550 DEG C, heating time 3.5-4.5h;Annealing temperature 450-550 DEG C, annealing time 19.5-20.5h;Fire stop in bell type furnace furnace cooling, cooling to 180-220 DEG C, take out air cooling to room temperature.The method of the application can effectively solve the problem of uneven internal stress of existing hot-rolled steel plate, which leads to the problem of poor plate shape after the release of internal stress after subsequent steel plate uncoiling or dividing.

The application belongs to the field of aero-engine test, and particularly relates to a bird impact test group gun launching high-speed shell design method, which is based on the shape of a uniform thin-walled cylinder structure shell, constructs a three-dimensional numerical simulation model of the shell and a shell ejection device, calculates stress and deformation results of the shell when the shell impacts the shell ejection device at a high bird speed, and finds out stress weak positions and displacement weak positions of the structure; the minimum size bird body that can be accommodated in the middle section and the rear section of the shell is taken as a constraint, the minimum inner diameters of the middle section and the rear section of the shell and the optimal buckling mode of the shell are taken as optimization targets, and the shell structure is subjected to topology optimization to obtain an initial shell profile; the internal stress of the shell does not exceed the material failure stress, and the total mass of the shell does not exceed the original mass, which are taken as constraint conditions, and the maximum energy absorption of the front end of the shell and the minimum deformation of the middle section and the rear section are taken as optimization targets, and the shell structure is subjected to topology optimization of size and shape to obtain an optimized shell.

The invention belongs to the technical field of residual stress detection, and particularly relates to a residual stress detection method of an electroceramic material, electronic equipment and a storage medium, the method comprises the following steps: obtaining zero-stress samples of a to-be-detected electroceramic material component, the zero-stress samples comprising a zero-stress tensile sample and a zero-stress compression sample; in a first preset temperature range, zero stress acoustic time calibration is carried out on the zero stress sample, and a zero stress acoustic time value is determined; carrying out stress coefficient calibration on the zero-stress sample, and determining an acoustic elastic coefficient; within a second preset temperature range, performing ultrasonic detection on the to-be-detected electro-ceramic material component to obtain a target sound time value; and determining the residual stress value of the to-be-tested electro-ceramic material component based on the zero stress acoustic time value, the acoustic elasticity coefficient and the target acoustic time value. According to the technical scheme provided by the invention, the residual stress detection of the electroceramic material is realized, the quality monitoring in the network access and operation inspection process is enhanced, and the safe and stable operation of a power grid is ensured.

The application discloses a kind of super-thick invar alloy plate of uniform organization and manufacturing method thereof, 6-9t invar alloy steel ingot is prepared by electric furnace→AOD refining→LF refining→VD refining→IC die casting process;Nb element is added in AOD refining process;After that, invar alloy steel ingot carries out stress relief annealing, and adopts three times upsetting and drawing process, upsetting reduction is according to the principle of increment, gradually refines steel ingot surface and heart grain structure, ensures that steel ingot internal organization is fully broken after recrystallization, then forged to target size after annealing, obtains invar alloy plate of thickness ≥50mm after air cooling;The application can prevent the grain coarsening of the heart of super-thick invar alloy plate with thickness greater than 50mm, and obtain super-thick invar alloy plate with grain size ≥4 levels and uniform organization.

The invention belongs to the technical field of bearings, and particularly relates to a large three-row cylindrical roller bearing initial clearance design method. The method comprises the following steps: firstly, according to actual working condition loading conditions such as pre-tightening force, axial load, radial load and overturning moment of a mounting bolt, carrying out stress analysis to determine the reduction amount delta a1 of the distance between axial raceway surfaces and the reduction amount delta r1 of the distance between radial raceway surfaces; secondly, according to the maximum permissible temperature difference delta T of the inner ring and the outer ring, the reduction amount delta a2 of the distance between the axial raceway surfaces and the reduction amount delta r2 of the distance between the radial raceway surfaces caused by the maximum permissible temperature difference delta T are determined; according to the form and location tolerance of machining, the reduction amount delta a4 of the axial clearance and the reduction amount delta r4 of the radial clearance of the bearing related to the form and location tolerance are determined. In addition, through stress analysis of the cylindrical roller, the axial working clearance ua and the radial working clearance ur when the cylindrical roller is subjected to the minimum load are determined. And finally, comprehensively considering factors such as stress condition, internal and external temperature difference, machining precision and the like, and determining an axial initial clearance ua0 = ua + deltaa1 + deltaa2-deltaa3 + deltaa4 and a radial initial clearance ur0 = ur + deltar1 + deltar2-deltar3 + deltar4 of the large three-row cylindrical roller bearing.

The invention relates to a simulation method, system and equipment for the bending performance of a concrete laminated slab, and belongs to the technical field of concrete construction.The simulation method comprises the steps that a target laminated slab meeting the optimal limestone powder mixing amount interval is screened from different-formula composite limestone powder concrete laminated slabs; constructing a laminated slab model according to the concrete data corresponding to the target laminated slab, and verifying the reliability; after the verification is passed, carrying out stress analysis on the test piece plate in the laminated slab model to obtain a first simulation value of theoretical cracking bending moment and a second simulation value of normal section flexural bearing capacity; calculating a first standard value of the theoretical cracking bending moment of the test piece plate and a second standard value of the normal section flexural capacity according to the concrete current standard; calculating the deviation ratio of the simulation value and the standard value; and when the deviation ratio is greater than a set value, correcting the parameters of the laminated slab model. The method has the beneficial effect of quickly analyzing the bending performance of the laminated slab.

The invention provides an old brick-concrete structure bearing capacity evaluation and reinforcement optimization method and system, and relates to the technical field of building structure safety evaluation, and the method comprises the steps: collecting stress data, carrying out stress analysis and safety level evaluation through a deep learning neural network, determining a weak part, and generating an initial reinforcement scheme; reinforcing parameters are optimized in combination with the graph neural network and reinforcement learning, an optimal reinforcing scheme is output and executed, the safety condition of the old brick-concrete structure can be accurately evaluated, a customized reinforcing scheme is provided, and the structural safety and reinforcing efficiency are improved.

The invention relates to the technical field of metal material surface treatment and high-strength spring manufacturing, and discloses a stress shot blasting process and equipment for a high-strength spring, and the process comprises the following steps: carrying out hot shot blasting on a quenched spring, and forming initial dislocation by using cast steel shots; carrying out controllable water cooling on the spring, and inducing phase change to construct a tissue foundation; fine steel shots are used for secondary cold shot blasting, and grains are refined to construct middle-layer stress; carrying out stress shot blasting by using modified tungsten carbide to construct a deep gradient stress field; cleaning and tempering the spring, performing coating protection, and performing quality detection; the equipment comprises first hot shot blasting equipment, water cooling equipment, second cold shot blasting equipment, third stress shot blasting equipment and a control system. Through four-step cooperative treatment of hot shot blasting, controllable water cooling, cold shot blasting and final stress shot blasting, gradient residual compressive stress fields with depth and stability are constructed on the surface layer and the subsurface layer of the spring, cyclic load tensile stress borne by the spring in the service process is counteracted, and the fatigue performance of the finished spring is improved.

The invention discloses a sample structure for studying the progressive destruction process of a solid material, the sample structure comprises a solid sample with a continuously changing cross section area, the cross section area of the solid sample is gradually increased or decreased between two end faces, and a test method specifically comprises the following steps: selecting a test loading mode applied to the solid sample; placing the solid sample according to a mode that the cross section is from small to large, and carrying out stress loading on the upper end surface of the solid sample by using a selected test loading mode; performing primary in-situ scanning imaging on the sample; based on the in-situ scanning imaging image, obtaining damage development conditions of cracks, micro cracks and the like at different positions of the solid sample, so as to obtain structure evolution conditions of the solid sample under the action of different load levels; determining a progressive failure process of a material corresponding to the solid sample in a specific loading form; according to the invention, the deformation state and the structure evolution stage of the sample under different load levels can be obtained through one-time loading by utilizing the non-uniform section characteristic of the sample.

A method for determining the length of the anchoring and bonding section of a rock bolt to adapt to the disturbance of cyclic tunneling, a test borehole is constructed on the roof; a fixed monitoring device is installed in the test borehole; during the tunneling operation, the fixed monitoring device is used to collect and store vibration signals; a portable acquisition terminal is used to receive and store the vibration signals; an industrial computer is used to receive the vibration signals and analyze and process them to obtain vibration excitation data; an anchoring test piece is made; a low-frequency vibration simulation test system is used to obtain vibration signal data according to the similarity ratio, and the anchoring test piece is subjected to vibration excitation according to the vibration signal data; then, an electro-hydraulic servo mechanics test system is used for pull-out testing; and finally, the loosening damage degree of the anchoring interface corresponding to different bonding lengths of the anchoring test piece is analyzed by comprehensively analyzing the pull-out stress, displacement data and acoustic emission monitoring data during the pull-out test. The method can effectively determine the length of the anchoring and bonding section of the rock bolt to adapt to the disturbance of cyclic tunneling.

The invention provides a strength design method for a deep-sea light ring rib cylindrical shell. The strength design method specifically comprises the following steps: (1) establishing a geometric model of the ring rib cylindrical shell when the ring rib cylindrical shell externally bears hydrostatic pressure; (2) carrying out stress analysis on the geometric model to obtain a cylindrical shell deflection curve expression containing unknown parameters; and (3) confirming boundary conditions of the geometric model, solving unknown parameters in the cylindrical shell deflection curve expression according to the boundary conditions, substituting the unknown parameters into the cylindrical shell deflection curve expression so as to obtain a complete deflection curve analytical expression, calculating stress values of different positions of the shell based on the deflection curve analytical expression, and calculating the stress values of different positions of the shell. And structural strength design is carried out according to geometric parameters of the ring rib cylindrical shell structure. The method is reasonable in conception, elastic boundary conditions are used at the ribs, the new boundary conditions can better describe the constraint condition of the reinforced cylindrical shell at the joint of the ribs and the shell according to material characteristics, and the method can be used for annular rib cylindrical shell structures of different materials and is more universal and accurate.

The invention relates to a three-dimensional surface residual stress prediction method based on end milling thickness differential calculation and moving heat source simulation. The method comprises the following steps: calculating a tool path in an end milling process; differentiating the machined surface generated in one rotation period, and calculating the cutting width of any differential unit; the shear force and the ploughing force of any infinitesimal are calculated through the constitutive relation and coordinate conversion; calculating the mechanical stress distribution of any infinitesimal in a rotation period; setting a moving heat source to simulate and calculate the thermal stress distribution of any infinitesimal; mechanical stress and thermal stress are coupled, the residual stress value of each infinitesimal element is calculated, and stress elastic-plastic loading and unloading calculation in a rotation period is carried out; inputting the residual stress distribution into a side wall influence function, and calculating to obtain final residual stress distribution of any infinitesimal in a rotation period; and cyclic calculation is completed by using a superposition method, and the residual stress distribution of the fully-machined surface is obtained. Compared with the prior art, the method has the advantages of improving the precision of residual stress calculation and the like.

The invention relates to the technical field of electrical digital data processing, in particular to a finite element-based tunnel frozen soil curtain stress field analysis numerical method and system, and the method comprises the steps: obtaining a three-dimensional model of a tunnel construction site and geological material characteristic data; performing grid division on the three-dimensional model to obtain a finite element grid model of the three-dimensional model; carrying out stress simulation on the finite element mesh model based on the geological material characteristic data, and obtaining an initial stress field of the finite element mesh model before freezing; based on the stress distribution condition of each unit grid in the finite element grid model in the initial stress field, analyzing the trend that the soil density changes in the freezing process, and determining a frost heaving stress field of the finite element grid model; and superposing the initial stress field and the frost heaving stress field to determine a comprehensive stress field of the finite element mesh model. According to the method, the accuracy of tunnel frozen soil curtain stress field analysis is effectively improved.

The invention discloses a residual life evaluation method and device for a mechanical spring, and belongs to the technical field of mechanical engineering, and the method comprises the steps: obtaining basic parameter information; performing fatigue analysis based on the basic parameter information and the historical use data; based on the initial predicted residual life, introducing load fluctuation, carrying out working stress and stress concentration factor conjoint analysis, introducing environmental change, carrying out working stress and surface treatment mode conjoint analysis, introducing material weakness distribution, and carrying out stress concentration factor and surface treatment mode conjoint analysis; and connecting a nano repair robot, repairing the target mechanical spring by using a programmable material, introducing multi-source monitoring equipment, obtaining a load fluctuation sequence, an environment change sequence and a material weakness distribution map, and obtaining a residual life evaluation result under the current working condition. According to the invention, the problem that the residual life of the mechanical spring cannot be accurately evaluated and the repair parameters cannot be optimized in a complex environment condition in the prior art is solved.

The invention discloses a simple chain-shaped dropper non-uniform arrangement method based on equal-elasticity space construction, relates to the technical field of bows, and aims at any cross-catenary, stress analysis is carried out on a positioner through a moment balance formula, a simulation model is constructed to carry out stress analysis on a positioning point, the optimal value of the distance between a first dropper and the positioning point is obtained, and the optimal value of the distance between the first dropper and the positioning point is calculated. The arrangement of the first dropper is completed; after the first droppers are arranged, the remaining droppers in the span area are arranged at equal intervals, a first sub-area and an adjacent second sub-area corresponding to the maximum elasticity of the span center area are analyzed through an equal-elasticity reference curve and an elastic gain, and the maximum elasticity of the two sub-areas is equal by adjusting the positions of the droppers on the left side and the right side of the second sub-area; therefore, an equal-elasticity space is constructed, and non-uniform arrangement of the simple chain-shaped droppers is completed. The problems that in the prior art, when the dynamic performance of the simple chain-shaped bow net system is improved, modeling and simulation are difficult, resources are consumed, and the simulation and actual deviation is large are solved.

The invention discloses an extrusion type basin normal fault identification method and device, and the method comprises the steps: building a spatial distribution pattern of a regional reverse fault based on a three-dimensional seismic data body after the inner horizon calibration of an extrusion type basin, and enabling the spatial distribution pattern to be used for determining the main trend of the regional reverse fault; the method comprises the following steps: under the background that an extrusion basin is in a compressive-torsional stress field, carrying out stress decomposition on the maximum principal compressive stress of a region to obtain a tensile stress component parallel to a main trend, and taking the tensile stress component as an optimal direction for normal fault identification; in the three-dimensional seismic data volume after horizon calibration, selecting an initial seismic section of which the orientation is parallel to a preferred direction, and executing small-interval translation scanning and / or small-angle rotation scanning on the initial seismic section to generate a series of scanning sections; and positioning the target position of the fault on a series of scanning profiles, and judging whether the hanging wall stratum moves downwards relative to the footwall stratum or not at the target position, and if so, identifying the fault as a normal fault. According to the invention, the normal fault of the extrusion basin can be accurately identified.

The invention discloses a special-shaped tunnel structure intelligent agent and an intelligent agent control method, and belongs to the field of tunnel engineering intelligent construction.The special-shaped tunnel structure intelligent agent comprises a tunnel structure intelligent agent composed of a shield segment structure, an intelligent sensing unit and a self-adaptive servo control unit; and an action strategy is automatically generated to carry out stress control, so that the stress deformation self-adaption reaches an optimized integrated structure system. The sensing unit is a laser range finder, an MEMS inclinometer and other deformation and mechanical sensing sensors arranged in a pipe piece and a servo control and inner supporting rod piece. The control unit is composed of active control equipment such as a permanent or temporary support servo actuator arranged in a stress concentration area. The stress deformation self-adaptive control of the whole structural intelligent body is completed by sensing the environmental state of the stress deformation of the structural system through the sensing unit and carrying out the autonomous generation and active application of the action strategy of the control unit through reinforcement learning.

The invention relates to the technical field of building structure engineering, in particular to an unreinforced masonry structure bearing capacity degradation simulation and reinforcement effect evaluation method, which comprises the following steps: constructing a general physical model, carrying out stress analysis, setting initial parameters, and introducing an environmental influence factor based on humidity and temperature to correct a degradation rate; building a masonry compression and shear strength degradation model by combining a time decay rule and environmental influence, further building a bearing capacity time-varying model, and simulating and outputting an unreinforced masonry bearing capacity time-varying change rule through a programming tool; a composite wall is constructed by adopting an outer wrapped concrete slab, equivalent strength is calculated based on an area weighting method, a bearing capacity time-varying model is established, a bearing capacity change rule after reinforcement is obtained through simulation, and quantitative evaluation of the reinforcement effect is achieved by comparing the equivalent strength and the bearing capacity time-varying model. According to the method, the crossing from static evaluation to dynamic prediction can be realized, the prediction precision is high, the operation is convenient, and a scientific basis can be provided for safety identification, durability evaluation and reinforcement decision-making of the existing masonry structure.

The invention relates to the technical field of air duct installation, in particular to a method for manufacturing and installing an air duct support on the outer side of a high-altitude inverted triangular pipe truss, which comprises the following steps: integrating an inverted triangular pipe truss model and an air duct structure model to form an integrated model; determining a structural form and a plane arrangement mode of the air duct bracket; creating a profile family self-adaptive to the size of the truss; establishing an air duct support model, and carrying out stress analysis and calculation; according to a stress analysis calculation result, a final air duct support model is generated; the preset position of the air pipe support is determined, and all profile components of the air pipe support are formed through prefabrication machining; splicing to form an air pipe bracket, and mounting the air pipe bracket on the inverted triangular pipe truss according to a preset position; and after the inverted triangular pipe truss is hoisted in place, the air pipe structure is installed on the air pipe support. By means of the method, the air pipe support can be spliced on site, welding is not needed, operation is very convenient and fast during construction, and the construction difficulty is greatly reduced.

The present application relates to the asymmetric force under fluctuating load bearing lining tunnel stability evaluation method, including: obtaining the two-way ground stress state around the tunnel, solving the asymmetric coefficient of stress;Establish the underground tunnel pressure bearing model and carry out stress analysis;Set the asymmetric load stress function, the elastic stress distribution is obtained by solving;Determine the function that the limit elastic principal stress of the first yield point of the tunnel satisfies, the first yield point position and its stress state are obtained by solving;Derive the stability condition of the tunnel structure under any stress, determine the safety load space and construct the plastic stress distribution conforming to the stability condition;Establish the self-balancing stress equation set of arbitrary load disturbance, the maximum value of the allowable stress value of the tunnel is obtained, and the safety allowable load range is drawn. The present application considers the asymmetric load condition of the tunnel, and has higher calculation accuracy and better application effect;The tunnel is analyzed in full plasticity, and the safety load obtained can well guarantee the stability of the structure.

The invention provides a double-coal-seam dirt band crossing fracturing simulation experiment device and method, and the device comprises a simulation stratum which sequentially comprises a top plate, an upper coal seam, a dirt band layer, a lower coal seam and a bottom plate from top to bottom; the horizontal stress loading assembly is used for carrying out stress loading on the simulated stratum in the horizontal direction; the vertical stress loading assembly is used for carrying out stress loading on the simulated stratum in the vertical direction; one end of the fracturing mechanism extends into the simulated stratum, the other end of the fracturing mechanism is connected with an external liquid supply assembly, and the fracturing mechanism is used for injecting fracturing liquid into the simulated stratum; the sensor assemblies are distributed on the upper coal seam, the dirt band layer and the lower coal seam. By means of the scheme, the problem that in the prior art, the indirect fracturing effect and the crack crossing expansion rule controlled by the layering stress under the double-coal-seam dirt band condition cannot be accurately reflected is solved.

The invention discloses a method for repairing a hatch cover of an ultra-large container ship without going down to the ground, which comprises the following steps of: a, carrying out stress analysis according to main parameters of the hatch cover, and confirming that a single tool pier meets the single-point 20-ton bearing capacity through calculation; b, counting 91 maintenance hatch covers of the whole ship, prefabricating 364 tool piers, and making load-bearing marks and number marks before use; c, after the ship enters a factory, the hatch cover is hoisted in situ through a gate seat hoisting rigging, and after the hatch cover is stabilized in the air, the tool pier enters a placing area; d, the tool pier is slowly moved to the position below four hatch cover limiting plates of the hatch cover; e, after the four tool piers are placed, workers evacuate from the hatch cover coverage area and return to the safety channel, the hatch cover falls on the tool piers through the gantry crane, and the workers overhaul the hatch cover. According to the method for repairing the hatch cover without going down the ground, the construction period in a dock is greatly shortened, the safety of the overhaul process is improved, and the cost is saved; and a solid foundation is laid for subsequent conventional repair of other ship types.