504 results about "Principal stress" patented technology

The invention relates to the technical field of computers, and discloses a digital twin hydraulic engineering operation and maintenance monitoring system which comprises a data acquisition module, a twin modeling module, a principal stress extraction module, a stress evolution prediction module, a safety domain judgment module, a regulation and control decision module, a control execution module and a state feedback module. The invention also discloses a digital twin hydraulic engineering operation and maintenance monitoring method, which comprises the following steps: data acquisition: real-time sensing data of a hydraulic engineering structure area is acquired through the data acquisition module, and the sensing data comprises strain, water pressure, temperature and displacement information and is used for representing the current state of the structure; and carrying out twin modeling, and receiving the real-time sensing data transmitted by the data acquisition module. According to the method, intelligent sensing and dynamic regulation and control of the structure state are realized by constructing a closed-loop system of principal stress prediction, regulation and control decision, control execution and state feedback.

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 provides a deep-buried soft rock tunnel supporting structure design method based on energy regulation and control, and belongs to the technical field of tunnel engineering. Comprising the following steps: obtaining components of crustal stress in a large principal stress direction, a middle principal stress direction and a small principal stress direction; manufacturing a rock cylinder test piece and a cube test piece; carrying out a conventional uniaxial compression test on the cylindrical test piece to obtain basic strength parameters of the surrounding rock; carrying out a true triaxial loading and unloading test on the cubic test piece to obtain the ultimate dissipated energy of the surrounding rock; drawing up a tunnel anchor rod supporting structure design scheme; establishing a deep-buried soft rock tunnel calculation model considering the synergistic effect of the surrounding rock and the anchor rod, and calculating the dissipated energy density of the surrounding rock and the absorbed energy of the supporting structure; the instability energy judgment basis of the surrounding rock and the instability energy judgment basis of the anchor rod are calculated; and judging the stability of the surrounding rock and the stability of the anchor rod. The method is suitable for the tunnel in a deep high-energy geological environment, and can reflect the energy driving essence of the instability failure of the high-ground-stress deeply-buried soft rock tunnel.

Provided is a method for judging geology of a time-delayed extremely intense rockburst as to deep tunnel engineering. Information about geological structures is recorded according to methods such as geological mapping and advanced geological prediction of the tunnel face. Geometric characteristics of burst craters formed during the rockburst are recorded by utilizing advanced geological drilling and profile scanning technologies in a rockburst-damaged zone. 3D geostress in the rockburst-damaged zone is measured by using a stress relief method or a hydraulic fracturing method to determine the orientation of the maximum principal stress. A 3D numerical calculation model is established based on initial geostress testing results and physical and mechanical parameters of rock and structural discontinuities obtained through on-site geological investigations. By conducting excavation simulations under different combinations of structural discontinuities and performing numerical calculation, the risk of time-delayed extremely intense rockburst disasters at current locations after tunnel excavation is judged.

The invention relates to a construction method of a potential sliding surface model for two-dimensional slope stability analysis, belongs to the field of engineering disaster prevention and reduction and computer aided design, and particularly provides a construction method of a two-dimensional slope potential sliding surface model in a principal stress deflection mode. According to the method, principal stress deflection is combined with the most unfavorable shearing direction by means of a side slope shear failure physical and mechanical model, a potential sliding surface model capable of effectively showing the actual sliding surface form when the side slope slides is constructed, meanwhile, known boundary conditions of a lower sliding-out point and an upper sliding-out point of the sliding surface are introduced, and the sliding surface is constructed. The method achieves the dual goals of reasonability and simplicity of potential sliding surface generation, further reliably improves the accuracy of slope stability evaluation under complex conditions, further provides powerful scientific guidance for slope collapse range definition and reinforcement area determination, and improves the slope stability evaluation accuracy. The implementation method has the advantages of being high in practicability, wide in application range, good in universality, high in calculation efficiency and the like.

The invention discloses a simulation part design method based on stress gradient fitting and a blade root characteristic simulation part. The simulation part design method comprises the following steps that S1, a dangerous area of a blade root part is determined based on simulation analysis of a turbine blade under a real working condition, and characteristic parameters are extracted; s2, designing a simulation piece examination section configuration based on a low-cycle fatigue simulation piece design criterion and the extracted characteristic parameters; s3, extracting the maximum stress gradient of the maximum first principal stress point of the blade root part of the turbine blade in a preset range in a preset direction, and carrying out normalization processing to obtain a stress gradient range of the blade root part of the real blade; s4, extracting the stress gradient of the simulation piece examination section, performing same normalization processing, comparing stress gradient fitting conditions, and performing fitting on the stress gradient by modifying and adjusting non-characteristic parameters of the simulation piece examination section and simulation piece configuration to control a stress gradient error; s5, a clamping section and a transition section are designed, and the strength of the clamping section and the strength of the transition section meet the requirement; and S6, the overall configuration design of the blade root feature simulation part is completed.

The invention relates to the technical field of crustal stress measurement, in particular to a rock core three-dimensional crustal stress measurement system and method based on multi-source data. The method comprises the following steps: acquiring well wall damage information, and identifying a damage type in the well wall damage information; multiple sections of core samples are selected based on the well wall damage information, and overburden pressure parameters are determined based on the multiple sections of core samples; a rock mechanics experiment is conducted on the rock core sample, rock mechanics parameters are generated, and the rock mechanics parameters comprise the Poisson's ratio, the Young modulus, the uniaxial compressive strength value and the tensile strength value. According to the method, the difference value of the maximum stress and the minimum stress is combined with the multi-source coupling constraint principal stress interval, the intersection points are identified through the topological visualization graph, the numerical range of the maximum principal stress and the minimum principal stress can be accurately determined, and then the information of the three-dimensional crustal stress is obtained.

The invention relates to the technical field of seismic source analysis and inversion, and discloses a seismic source analysis and inversion system based on mine earthquake monitoring, which is characterized in that energy parameters are generated through waveform feature extraction, mine earthquake event identification and accurate positioning are realized by using a space-time aggregation rule, and seismic source mechanism parameters are inverted in combination with a seismic wave initial motion parameter and amplitude relationship. On the basis, a regional stress field initial inversion model is constructed, a stress gradient is calculated in combination with a working face track and stratum information, a principal stress rotation composite index is determined through interlayer mechanical difference and a spatial change rate, and self-adaptive deformable partitions are generated. And finally, secondary stress field inversion is carried out in the subareas, the corrected maximum principal stress direction is output, high-precision dynamic analysis of a mine earthquake mechanism and stress distribution is realized, and the mine disaster prediction and early warning capability is remarkably improved.

Embodiments of the present invention relate to the technical field of shale gas development, and provide a method and system for predicting the maximum horizontal principal stress of shale gas reservoirs. The method comprises: performing cross-arranged gather extraction on acquired original shot gathers to obtain corresponding OVT gathers, and preprocessing the OVT gathers; acquiring well logging data, performing well-to-seismic calibration and seismic horizon interpretation on the basis of the well logging data, and obtaining an interpreted horizon of the current reservoir that meets in-situ stress prediction as a target horizon; constructing a low-frequency model on the basis of the well logging data and the target horizon, and calculating a Poisson's ratio and a fracture density on the basis of the low-frequency model; calculating a vertical principal stress of the target horizon on the basis of a velocity field, a formation density and a density inversion body; and calculating the maximum horizontal principal stress of the current reservoir on the basis of the Poisson's ratio, the fracture density, the vertical principal stress and a preset principal stress solving model. The solution of the present invention solves the problem of low accuracy in existing solutions for predicting the maximum horizontal principal stress of shale gas reservoirs.

The invention discloses a method for determining the axis direction of an underground powerhouse of a pumped storage power station and a construction method, and aims to solve the problem of balance between a dominant included angle theta between the axis of the powerhouse and the direction of a geological structure surface and a dominant included angle eta between the axis of the powerhouse and the direction of a maximum horizontal principal stress in an axis diagram mode. The information is displayed efficiently, accurately and clearly, and the field survey and application efficiency is improved; the balance point between the dominant included angle theta between the plant axis and the geologic structure plane direction and the dominant included angle eta between the plant axis and the maximum horizontal principal stress direction is calculated in a quantitative mode, so that the obtained plant axis direction is more accurate and objective.

The invention discloses a method for rapidly judging the surrounding rock stability of a shallow-buried large-span tunnel in an upper-soft and lower-hard stratum, and relates to the technical field of tunnel engineering design. Constructing a physical plane graph according to the engineering design drawing; mapping the physical plane graph to an image plane through a conformal mapping function; generating a stress field analytic equation corresponding to the physical plane according to each parameter in the image plane graph and the complex variable function analytic form; calculating a plurality of different principal stresses of the surrounding rock through the stress field analytic equation, calculating a shear failure stress according to the plurality of different principal stresses, and obtaining an expression between the normal stress and the shear stress of the surrounding rock; and defining the shear failure shear stress as tau c, the shear stress as tau and the shear safety coefficient as s = tau / tau c, judging whether s is greater than 1 or not, and if so, considering that the unit rock mass meets the failure condition. The method aims at quickly and accurately evaluating the surrounding rock stability of the large-span tunnel in the upper-soft and lower-hard stratum, and the safety risk and the cost pressure faced by tunnel construction are reduced.

The invention relates to the technical field of coal underground gasification control, in particular to a stable control method for the gasification process of deep coal passing through dirt band. The gas pressure distribution data and the pore change characteristic data of the deep coal gasification area are collected in real time through the distributed sensor array, the gas dynamic correction permeability is generated, the gas injection pressure is adjusted and dynamically corrected according to the gas dynamic correction permeability, and the gas pressure is kept stable; screening a potential risk area through a main stress direction deviation angle and a stress concentration coefficient in the dirt band layer, analyzing a shear stress threshold value of the potential risk area based on a stress-strain coupling model, and judging a stability evaluation index of the potential risk area; and when the stability evaluation index is lower than a threshold value, a multi-stage emergency regulation and control mechanism is triggered, and a dirt band layer reinforcement intervention scheme is generated. By means of multi-source data fusion and a dynamic feedback mechanism, the limitation of a traditional method for lagging response of the instability risk of the dirt band layer is broken through, and full-closed-loop intelligent stable control over the gasification process is achieved.

The invention provides a structural design optimization method and device for an underground station constructed through a shield tunneling method, and belongs to the technical field of underground engineering.The method comprises the steps that site geological survey data of a station trepanning area are obtained and input into a three-dimensional finite element model, and an initial three-dimensional model is constructed; analyzing a dynamic load effect in a construction stage by combining a load reduction theory to obtain a target three-dimensional model; finite element analysis is carried out based on the target three-dimensional model, and the maximum principal stress of the edge of the opening is extracted; then comparing the maximum principal stress with the allowable stress of the material, and performing load reduction iteration under the condition that the maximum principal stress is greater than the allowable stress of the material to obtain a final load reduction coefficient; and taking the final load reduction coefficient, the trepanning center coordinate and the stress concentration factor as the input of a two-dimensional reinforcement model, generating an equivalent live load, calculating the reinforcement amount, and automatically realizing the reinforcement optimization design. The construction efficiency is improved and the engineering cost is reduced while the safety and stability of the structure are ensured.

The invention discloses a semi-analytical method for mechanical response analysis of an underground compressed air energy storage circular cavity, and belongs to the field of underground compressed air energy storage. According to the method, the thought of the finite difference method is adopted, the plastic zone radius and stress distribution of the lining-surrounding rock composite structure can be accurately given, and theoretical support is provided for design of the underground compressed air energy storage circular cavern. According to the method, a semi-analytic solution result is consistent with an elastic analytic solution result in a material elastic stage; the elastic-plastic state semi-analytical solution result considers that the principal stress of the material in the plastic state is always on the yield surface, so that the elastic-plastic state semi-analytical solution result is more accurate than the calculation result of the elastic analytical solution.

The invention relates to an aero-engine stator part crack critical dimension comprehensive determination method and system, and belongs to the technical field of aviation, the method comprises the following steps: obtaining an aero-engine typical hot end stator part geometric model and material parameters, and carrying out static strength analysis according to fluid-thermal-solid coupling load characteristics in actual working conditions; inserting an initial crack into a first principal stress plane of a dangerous part of the real component, carrying out crack propagation simulation to determine a crack propagation path, and calculating a critical crack size of a dangerous point; analyzing critical crack sizes under different failure modes, such as cooling failure and buckling failure; and integrating analysis results under the multi-failure mode, and determining a comprehensive critical dimension as a final judgment standard. According to the method, through combination of fracture failure and function failure analysis, accurate judgment of the critical dimension of the crack is realized, limitation of a traditional single fracture criterion is broken through, comprehensive function failure analysis is realized, the accuracy of a maintenance decision is remarkably improved, and a scientific basis is provided for condition-based maintenance decision.

The invention relates to the technical field of geological engineering safety risk evaluation, in particular to a regional tectonic stress risk quantitative analysis method for tunnel engineering. The method comprises the following steps: collecting multi-source geomechanical parameters, simulating and inverting a tectonic stress field, and verifying the tectonic stress field; constructing a multi-scale geomechanical model, coupling simulation tectonic stress and gravity stress, and generating a stress space basic layer; utilizing Kriging interpolation and inversion decomposition to obtain a stress value and a directional diagram layer; calculating an included angle between the maximum principal stress direction and the tunnel axis, and performing vector decomposition to obtain a vertical stress component; and carrying out standardized normalization on the factors, determining a weight calculation risk value, and finally generating a tectonic stress risk quantitative grading graph and carrying out GIS visual rendering. The tunnel engineering-oriented risk quantitative analysis mechanism is constructed by retaining the directivity and spatial heterogeneity characteristics of the tectonic stress tensor, and the authenticity, resolution and engineering applicability of tectonic stress identification are remarkably improved.

The invention provides an elastic-plastic unified description method and system for nonlinear characteristics of surrounding rock considering medium-principal stress, and belongs to the technical field of computer aided design. The method comprises the following steps: carrying out a true triaxial mechanical property test on surrounding rock to obtain a surrounding rock total stress-strain curve, extracting characteristic stress points of the stress-strain curve, and carrying out stage division on the stress-strain curve; constructing a characteristic yield surface in the stress space based on the characteristic stress points; based on the staged characteristics of the stress-strain curve, plastic deformation capacity characterization functions of different stages are constructed respectively, and the plastic deformation capacity characterization functions are used for describing the plastic deformation capacity of the stress-strain curve; and constructing a nonlinear hardening-softening equation to describe evolution characteristics of the characteristic yield surface. According to the scheme, the nonlinear characteristics of the stress-strain curve can be more comprehensively and accurately described under different minimum principal stresses and medium principal stresses.

A deep engineering hard rock true triaxial dynamic disturbance aging fracture testing device belongs to the technical field of rock mechanics tests and comprises a counter-force frame, a pressure chamber and six main stress linear disturbance actuators. The main stress linear disturbance actuator comprises a linear disturbance motor and a main stress hydraulic cylinder; the linear disturbance motor is coaxially and fixedly installed at the outer end of a cylinder barrel of the main stress hydraulic cylinder, a dowel bar is arranged in a central hole channel of a piston rod of the main stress hydraulic cylinder, and a power output shaft of the linear disturbance motor is coaxially and fixedly connected with the dowel bar. According to the utility model, the matching form of a traditional dynamic actuator and a hydraulic oil source is abandoned, the linear motor is introduced into the true triaxial test equipment as a power disturbance source, the long-time dynamic disturbance structure of the true triaxial test equipment is simplified, and the energy consumption of the equipment is greatly reduced after the linear motor is used as the power disturbance source; the maintenance process is simpler, the maintenance cost is greatly reduced, the installation and debugging processes of the linear motor are more time-saving and labor-saving, and no extra floor area is needed.

The invention discloses a rock burst prediction type control system for geotechnical engineering tunnel construction. The rock burst prediction type control system comprises a data acquisition layer, a data processing layer and a control layer. The data acquisition layer captures rock fracture signals, surrounding rock stress evolution and tunneling state data in real time. The edge calculation layer is used for executing data preprocessing, feature extraction, local model training and real-time reasoning; the federated learning layer is used for constructing a teacher-student model by utilizing a knowledge distillation technology, compressing a global model, and encrypting and transmitting the compressed model to the edge calculation layer through a LoRa module; a rockburst prediction layer: fusing an FLAC3D principal stress vector field as a NeRF position code, constructing an anisotropic radiation field according to a joint surface topological relation extracted by a graph neural network, dynamically adjusting overall rendering density in combination with a microseismic energy release rate, and integrating a physical model and a machine learning model through a Bayesian framework to output a risk probability; and the intelligent decision-making layer is used for generating a multi-objective optimization scheme based on a reinforcement learning framework in combination with digital twinborn simulation, and matching a preset working condition-measure pair through a rule engine.

The invention discloses a design method of a periodically-arranged porous thin-wall combustion chamber flame tube characteristic simulation piece, which comprises the following steps: carrying out fluid-thermal-solid coupling analysis in a real structure service environment, obtaining the temperature field distribution of a combustion chamber flame tube and the size and direction of a first principal stress, and determining a part with the maximum first principal stress as a dangerous part; inserting an initial crack into a dangerous part of a real component, carrying out crack propagation numerical simulation, and extracting a stress intensity factor change rule on a crack propagation path; on the basis of keeping key geometric characteristics of a periodically arranged porous structure, a simulation piece is configured and designed into a biaxial flat plate stretching piece, and stress gradient distribution of a real component is matched through porous array parameter optimization; a biaxial tensile testing machine is adopted to apply a multi-axial load to the simulation part, and it is ensured that the stress intensity factor amplitude under different crack lengths is kept consistent with that of a real component. The method has important engineering value for damage tolerance evaluation and life prediction of the aero-engine combustion chamber.

The invention relates to a fault stability evaluation method considering a pressure-stress coupling effect. The method comprises the following steps: calculating a pressure-stress coupling ratio according to target layer rock mechanical parameters or field actual measurement pressure and ground stress data; fault three-dimensional structure modeling is carried out based on the seismic interpretation result, and fault occurrence distribution is simulated and calculated; analyzing and calculating the initial stress of the section and the stress after the coupling action by combining the three-way principal stress, wherein the stress comprises shear stress and effective normal stress; a quadratic equation of unary about fault instability critical pressure is constructed, and fault instability risk types are judged in combination with the actual pressure limit of oil field production; and calculating the critical pressure of fault instability under different risk types. According to the method, the influence of the pressure-stress coupling effect on the fault stability can be considered, so that the fault stability evaluation result is more practical.

The invention belongs to the field of crustal stress measurement, and discloses a crustal stress measurement method based on an indentation technology and machine learning, which comprises the following steps: firstly drilling a rock core, and processing the rock core into a sample; performing a shallow indentation test to obtain an indentation load-displacement curve, and obtaining a rock core equivalent elastic model; carrying out a deep indentation test, and taking test data as an actual training sample of machine learning; inputting the actual training sample training set into a neural network for network training to obtain a ground stress inverse problem model; carrying out an in-situ indentation test, and calculating to obtain a minimum horizontal principal stress and a maximum horizontal principal stress according to the rock core equivalent elastic model; measuring a drilling well bottom indentation main crack direction by means of an imaging logging instrument, wherein the drilling well bottom indentation main crack direction is the maximum horizontal main stress direction; the earth deep rock crustal stress measurement method is constructed based on an indentation technology and machine learning; compared with an existing conventional rock mechanical property measurement technology, the indentation technology is convenient to operate, and in-situ testing can be carried out on mechanical behaviors of rocks in the deep part of the earth and in a large deformation area of soft rocks.

The invention provides a rock damage simulation method and device, and relates to the technical field of rock engineering. The method comprises the following steps: applying a load to a numerical model of a rock to be measured, simulating the numerical model based on least square near-field dynamics, and judging whether the numerical model has tensile failure and / or shear failure by utilizing a maximum principal stress criterion and a Mohr-Coulomb criterion; when the numerical model is not damaged, increasing the load applied to the numerical model until any damage occurs to the numerical model; and judging whether the current total load step reaches a preset total step number or not after the damage occurs, if the current load is not kept unchanged, continuing to apply the load to the numerical model until the current total load step reaches the preset total step number. According to the method, two criteria are used for identifying different damage behaviors of the rock, tensile damage and shear damage of the rock can be accurately described, the rock damage process is more accurately simulated, and disaster prediction and prevention and control in the field of rock engineering are facilitated.

The invention belongs to the field of rock mass engineering, and provides a cyclic test method for simulating the principal stress of a three-surface joint distribution rock, which comprises the following steps: step 1, sample processing; step 2, placing the concrete sample on a bearing bracket; 3, the loading device A loads the pressure # imgabs 0 #, the loading device B loads the pressure # imgabs 1 #, the loading device C loads the pressure # imgabs 2 #, and the loading device A loads the pressure # imgabs 0 #, the loading device B loads the pressure # imgabs 1 #, the loading device C loads the pressure # imgabs 2 #, and the loading device B loads the pressure # imgabs 3 #; the loading device A loads # imgabs4 # to # imgabs5 #, and # imgabs6 # is recovered after the loading device A is stable; the positions of the loading device A and the loading device B are exchanged, then the loading device A loads # imgabs7 # to # imgabs8 #, and # imgabs9 # is recovered after stabilization; the positions of the loading device A and the loading device C are changed, then the loading device A loads # imgabs 10 # to # imgabs 11 #, the sigma is reduced before the concrete sample reaches a yield point, and # imgabs 12 # is recovered after the concrete sample is stabilized; 4, progressively increasing # imgabs13 #, and repeating the step 3 until the concrete sample is damaged; according to the invention, the stress of the sample in different directions can be variably loaded, and the consistency and uniformity in the test loading process are ensured.

The invention discloses a complex formation well wall stability prediction method, system and equipment and a medium. The method comprises the following steps: acquiring actually measured formation data of a drilled reservoir section; calculating formation pore pressure and rock mechanical parameters according to actually measured formation data; calculating the crustal stress according to the formation pore pressure and the rock mechanical parameter profile; taking the additional density zero of the slurry as an initial value, taking the tectonic strain coefficient in the horizontal minimum principal stress direction and the tectonic strain coefficient in the horizontal maximum principal stress direction as initial tectonic strain coefficients, and obtaining the initial pore fluid pressure, the horizontal minimum principal stress and the horizontal maximum principal stress of the stratum on the basis of actually measured stratum data; the collapse pressure equivalent density and the fracture pressure equivalent density of the drilled well can be obtained according to the collapse pressure equivalent density calculation formula and the fracture pressure equivalent density calculation formula; and when the pressure corresponding to the drilling mud density is larger than the collapse pressure equivalent density and smaller than the fracture pressure equivalent density, the well wall is stable.

The invention belongs to the field of airplane strength fatigue life prediction, and particularly relates to an equivalent stress-based airplane typical structure multi-axial fatigue life prediction method. The method comprises the steps of determining a typical aircraft high-lock connection structure test piece; determining a fatigue load spectrum; constructing a finite element model of the typical high-lock connection structure of the aircraft; determining a dangerous part of the airplane typical high-lock connection structure test piece in finite element analysis; determining the maximum principal stress at the dangerous part of the typical airplane high-lock connection structure test piece in finite element analysis; determining the fatigue life of the test piece; fitting S-N curve data under different stress ratios according to the fatigue life of the test piece and the load spectrum stress ratio, and determining a corrected S-N curve; determining an equivalent stress-life equation of the typical high-lock connection structure of the aircraft, and substituting the maximum principal stress and fitting parameters of the corrected S-N curve into the equivalent stress-life equation to calculate and obtain a fatigue prediction life; and correcting the fatigue prediction life according to a test result.

The invention provides a topological optimization method for a tension / compression structure. The method is based on a three-phase material model formed by pure tension, pure compression and empty attribute materials. According to the method, the discrete design domain of the mixed stress unit is adopted, the unit tension / pressure state judgment criterion based on the principal stress value and the tension / pressure tolerance is formulated, the tension / pressure state of the unit can be more accurately determined, and therefore material distribution based on the unit stress state is achieved. And finally, deriving the sensitivity of the target function to the design variable, and filtering the sensitivity by using a three-field filtering technology.

The invention relates to the technical field of additive manufacturing, and discloses a 3D printing continuous fiber reinforced composite material path planning method based on the absolute maximum principal stress direction, and the method comprises the steps: building a three-dimensional model of a to-be-formed structural member, carrying out the slicing processing of the three-dimensional model, and obtaining a two-dimensional model of the to-be-formed structural member and the geometric characteristics of the two-dimensional model; material parameters and load constraints are set for a to-be-formed structural part needing additive manufacturing according to the requirements of forming materials and structural working conditions, finite element simulation is carried out, and a finite element simulation calculation result of a unit is exported; on the basis of a finite element simulation calculation result, an original contour line based on the stress direction is obtained through calculation; and on the basis of the calculated contour line in the stress direction, the additive manufacturing path of the to-be-formed structural part is obtained. The effect of improving the mechanical property of the continuous fiber composite material structure is achieved, and the mechanical property of a composite material component is improved on the premise of the same fiber content.

The present invention relates to the technical field of oil-gas exploration. Provided are a method and apparatus for determining the minimum horizontal principal stress of a shale oil reservoir. The method comprises: using a shallow resistivity curve to calibrate a conductivity curve, so as to obtain a high-resolution resistivity curve; using oil porosity information to calibrate nuclear-magnetic-resonance-logging data, so as to determine a continuous oil saturation curve; determining a continuous saturation index curve according to elemental capture spectroscopy data and rock electrical-experiment data; determining a high-resolution full-water-saturation resistivity curve according to the high-resolution resistivity curve, the continuous oil saturation curve and the continuous saturation index curve; using a high-resolution static Young's modulus calculation model to determine a high-resolution static Young's modulus; and further determining a continuous minimum horizontal principal stress. The present invention can improve the resolution of the minimum horizontal principal stress of a shale oil reservoir.

The hydraulic fracturing construction method comprises the following steps that S1, the physical and mechanical properties of a coal mine working face roof are tested, the firmness degree of roof rock is determined, and the area of the end suspended roof is evaluated; s2, through theoretical analysis and numerical calculation, the influence of several different influence factors such as the water injection rate, the main stress difference, the fracturing sequence and the drilling inclination angle on hard roof fracturing damage weakening is explored, and reference is provided for hydraulic fracturing site construction design; s3, hydraulic fracturing construction parameters of a working face end suspended roof are determined; and S4, hydraulic fracturing construction is conducted according to the determined construction parameters. According to the method, a hydraulic fracturing method is used, high-pressure fluid is injected into a target hard rock stratum, so that a crack is generated or a natural crack is restarted, a rock stratum structure is transformed, a crack network system is formed, the purposes of weakening an end hard top plate and timely collapsing are achieved, the weighting strength of the top plate is reduced, and the safety of a working face is guaranteed.