17 results about "Uniaxial compression" patented technology

The application discloses a kind of mesoscopic parameter multistage calibration method suitable for discrete element linear contact bonding model.The method follows the three-level progressive system of "single component-mixture-structure", and adopts the decoupling strategy of "stiffness first, strength later".Firstly, based on the uniaxial compression simulation of single component and mixture, the mapping relationship between macro modulus and mesoscopic normal stiffness is established to calibrate the stiffness parameter, and the parameter precision is further improved by structure load model fine tuning;then, based on the splitting simulation of single component and mixture, the mapping relationship between macro strength and mesoscopic tensile strength is established to calibrate the strength parameter.The method solves the problem of low efficiency and unclear physical meaning of traditional trial-and-error method, significantly improves the efficiency, accuracy and physical reasonableness of discrete element mesoscopic parameter calibration.

This invention relates to a dual evaluation method for fracturing performance of shale reservoirs based on a cohesion-friction-bedding coupling model. It includes: preparing shale samples with different bedding angles; conducting Brazilian splitting experiments, uniaxial compression experiments, and triaxial compression experiments to obtain time-load curves and stress-strain curves for shale at different bedding angles; and constructing a shale brittleness index under uniaxial stress. B un Determine the degradation coefficient of shale brittleness due to confining pressure. B wc Constructing the brittleness index of shale under triaxial stress conditions B tr Shale brittleness index under triaxial stress conditions B tr This invention combines well logging data to predict the distribution of rock brittleness across the entire block and well section, clarifying reservoir compressibility, and integrates with geological modeling software to predict fracture morphology and fracturing effectiveness. This invention solves the problems of inconsistent rock brittleness assessment results and the difficulty in combining them with geophysical data for application in anisotropic shale, which negatively impacts shale reservoir fracturing design and fracturing effectiveness evaluation.

The invention relates to a method and a system for measuring strain of an ice sample in a uniaxial compression test process by using a crystal texture digital image. The method comprises the following steps: preparing the ice sample: preparing the ice sample according to a predetermined direction of the uniaxial compression test; polarized light imaging arrangement: placing the ice sample between a chassis and a pressure plate of a uniaxial compression testing machine; a cold light source with adjustable brightness is arranged behind the ice sample, and a polaroid is arranged between the cold light source and the ice sample; arranging a high-speed camera in front of the ice sample and installing a polarized lens to receive polarized light passing through the ice sample; adjusting image quality: enabling the length direction of the ice sample to be along the loading direction of a tester and the thickness direction to be along the light path direction of polarized light; uniaxial compression test and synchronous acquisition; calculating a strain field: calculating a strain field and a deformation field of the surface of the ice sample according to a digital image correlation method based on the polarized light grayscale images of the ice sample at adjacent moments; and identifying crack propagation.

The method for evaluating the fracture mechanics performance of the water-soaked brittle solid material of the present application comprises the following steps: 1. A group of cuboid brittle solid material samples are prepared, and the samples are immersed in water. After the immersion is completed, the samples with different immersion times are selected for weighing, and then the samples with different water contents are selected; 2. The samples with different water contents in step 1 are selected, and the relationship curve between the uniaxial compression stress and strain of the brittle solid material samples and the initial density of the micro-defects of the samples under different water contents are measured; 3. The samples with different water contents in step 1 are selected, and the sliding friction coefficients of the brittle solid material samples with different water contents are determined; 4. The brittle solid samples containing cracks are prepared, and the fracture toughness of the brittle solid material with different water contents is measured; and 5. Based on the above steps, the fracture strength of the brittle solid material samples under the action of different water contents after being soaked in water is determined.

This invention discloses a method for monitoring the surface deformation evolution process of rock undergoing uniaxial compression creep failure, belonging to the field of geotechnical and rock mechanics testing technology. The steps are as follows: Step 1: Set up a test platform, which includes a speckle spraying system, an imaging and illumination module, a test device, and a host computer; Step 2: Fabricate rock test specimens and arrange the imaging and illumination module; Step 3: Obtain the compressive strength and set the graded loading levels; Step 4: Form a white base layer and black speckles on the surface of the rock specimen, meeting the requirements; Step 5: Conduct a uniaxial graded loading creep test on the rock specimen and acquire image data; Step 6: Process the image data to obtain the strain field evolution process on the specimen surface. This invention uses the above method to record the changes of the white base layer and black speckles during compression using an imaging device, thereby obtaining the deformation creep failure characteristics and evolution law of the rock surface.

The application discloses a method for rapidly evaluating the compressive toughness of tailing cementing material based on the fiber content-concentration effect, and the method comprises the following steps: tailing and cement are mixed to form a base material; a non-fiber tailing cementing material test piece is prepared by using the base material with a mass concentration of 65% as a standard test piece; non-fiber tailing cementing material test pieces with mass concentrations of 68% and 72% are prepared by using the base material; a tailing cementing material test piece with a fiber content of 0.5% is prepared; and a tailing cementing material test piece with a fiber content of 0.7% is prepared; the uniaxial compression test is performed on the test pieces to obtain the ultimate strain values of the test pieces; and the tailing cementing material test piece with the highest increment of the defined ultimate strain factor K is the best tailing cementing material.

The application belongs to the technical field of material mechanical property testing and nondestructive testing, and specifically discloses a uniaxial compression ultrasonic stress testing method and device, which comprises the following steps: placing a sample to be tested in a loading device, applying a preload to the sample to be tested and unloading to a zero stress state, collecting the longitudinal wave propagation time, the transverse wave propagation time and the initial length of the sample to be tested in the zero stress state; applying a uniaxial compression load to the sample to be tested, and synchronously collecting the axial load, the piston displacement, the longitudinal wave propagation time and the transverse wave propagation time; calculating the relative change rate of the ultrasonic wave velocity, establishing a coupling relationship model between the uniaxial compression stress and the relative change rate of the ultrasonic wave velocity; and decoupling and inverting the actual stress inside the sample to be tested according to the coupling relationship model. The application solves the problem that the prior art does not fully consider the coupling influence of the microstructure change of the material on the ultrasonic wave signal in the compression process, thereby leading to insufficient precision of the stress inversion model.

The application discloses a rock uniaxial compression test data processing method, system, device and medium, relates to the rock mechanics technical field, and includes the following steps: acquiring rock uniaxial compression test data collected through a rock mechanics testing machine, intercepting and processing the rock uniaxial compression test data according to a preset extreme value data intercepting method to obtain target test data; fitting the target test data to obtain a stress-strain curve after fitting, acquiring an instantaneous change rate of stress corresponding to strain in the stress-strain curve after fitting, and intercepting a target fitting curve whose instantaneous change rate meets a preset elastic stage data condition; and performing double linear regression analysis on the target fitting curve in axial strain-stress and radial strain-axial strain respectively to obtain an elastic modulus result and a Poisson's ratio result of the rock uniaxial compression test data. Through automatic processing of the flow, human error is avoided, and the efficiency, accuracy and reliability of rock uniaxial compression test data processing are improved.

This invention belongs to the field of marine engineering technology and discloses a method for constructing a numerical model of ice materials and a method for predicting ice loads. The construction method provided by this invention includes: obtaining experimental data by conducting uniaxial compression tests on ice materials under different strain rate conditions; establishing a hybrid hardening model including isotropic hardening and kinematic hardening, and introducing the Cowper-Symonds strain rate model to correct the yield strength, thereby obtaining a constitutive expression for the ice material including parameters to be calibrated; calibrating the parameters to be calibrated based on the experimental data, thereby obtaining a constitutive model of the ice material that simultaneously considers strain rate effects and hardening effects; and establishing a nodal failure mechanism corresponding to the failure criteria of the ice material, thereby obtaining a numerical model of the ice material that simultaneously considers strain rate effects, hardening effects, and failure behavior. This invention also utilizes the numerical model of the ice material for ice load prediction. This invention can improve the accuracy of numerical simulation of ice loads.

The present application relates to the technical field of rock mechanics test monitoring and safety early warning, and specifically discloses a failure early warning device and method for rock uniaxial compression test, which comprises the following steps: real-time acquisition of load data and displacement data of rock samples in the process of rock uniaxial compression test; preprocessing of the load-displacement data and determination of the optimal sliding window length; calculation of real-time tangent stiffness and stiffness degradation rate of the rock samples in the process of loading; conversion of the load-displacement data into stress-strain data, obtaining of dissipated energy and dissipated energy change rate; construction of continuous damage variable and obtaining of damage evolution rate; weighted combination of the stiffness degradation rate, the dissipated energy change rate and the damage evolution rate, obtaining of a comprehensive early warning index and analysis of the evolution trend, determination of whether the rock sample enters the instability early warning range, and output of early warning information. The present application can realize early identification of the instability development trend of rock, significantly improve the safety of the test, and has a wide range of application.

The application provides a model material optimization method and system for comprehensive quantitative evaluation of strength and deformation indexes, and the method comprises the following steps: obtaining two types of samples and performing uniaxial compression experiments on the two types of samples, the model material samples comprising multiple groups of model material samples; obtaining a strength response deviation of the model material samples based on uniaxial compression test results of the two types of samples and similarity theory; obtaining stress-strain curves of corresponding samples based on the uniaxial compression test results of the two types of samples, and then determining multiple characteristic points, the characteristic points comprising a peak stress point and multiple deformation characteristic points; obtaining a deformation index deviation of the model material samples based on the compressive strength of each characteristic point and the slope of a linear fitting curve between any two characteristic points by using the compressive strength of each characteristic point; obtaining a comprehensive deviation of each group of model material samples based on the strength response deviation and the deformation index deviation, and selecting a group of model material samples corresponding to the minimum comprehensive deviation as optimal model material for building a physical similar model.

This invention discloses a method for constructing a modified constitutive model of rock considering the pore compaction stage. First, the rock is divided into several micro-elements containing different defects, and it is assumed that these micro-elements conform to the generalized Hooke's law, that the strength of each micro-element follows the Weibull statistical distribution, and that the failure criterion for the micro-elements is the Drucker-Prager criterion. Next, a uniaxial compression constitutive model considering the pore compaction stage of the rock is established based on the Drucker-Prager failure criterion and the Weibull distribution. Then, the established model is compared and verified with experimental data. Finally, a modified uniaxial compression constitutive model of rock considering the pore compaction stage is established, and the modified model of this invention is verified using the uniaxial compression test results of coarse-grained marble after high-temperature damage. The method of this invention has clear physical meanings for the parameters, is well-organized, logically sound, has a wide range of applications, is simple and easy to implement, and can well reflect the uniaxial compression mechanical behavior of rock considering the pore compaction stage.

This invention provides a multi-scale assessment method for rockburst tendency in cavern surrounding rock, including the steps of preparing cavern surrounding rock samples and high-temperature heat treatment, uniaxial compression test three-dimensional displacement and strain data, constructing failure quality and energy density indices, energy evolution analysis, strain localization spatial quantitative analysis, and multi-scale comprehensive assessment of rockburst tendency. This invention constructs a dual-index rockburst tendency assessment system based on failure quality and energy density, achieving a combined quantitative and qualitative evaluation of rockburst intensity. For the first time, it combines three-dimensional digital image-related full-field strain data with spatial point pattern analysis methods, realizing a leap from qualitative description to spatial quantitative index of strain localization. It also reveals the evolution law of rockburst tendency under high-temperature-fracture coupling, constructs a multi-scale rockburst assessment framework, and achieves quantitative characterization of the entire process from energy input to strain instability.

The present application belongs to the technical field of building materials, and relates to a seawater coral reef sand concrete damage effect test method. The present application determines the reference compressive strength through a uniaxial compression test, determines the driving parameters for formal impact by using a split Hopkinson pressure bar combined with pre-impact closed-loop calibration; based on the stress balance criterion, the effective waveform is screened to calculate the dynamic stress peak value, and the fragment dimension of the test piece is extracted; after normalization, the three are fused to calculate the damage effect index. The method effectively solves the problems of dynamic load mismatch, waveform distortion interference and single index difficulty in quantifying the irregular characteristics of crushing, realizes multi-dimensional comprehensive quantification of static reference, dynamic response and crushing form, and improves the repeatability of impact test data and the objective comparability of damage evaluation of different proportioning materials.

The application discloses a kind of ore cumulative damage constant calibration method based on single-axis compression and drop ball impact test, belong to the technical field of damage condition in ore crushing process.It includes the following steps: first, obtain the fracture energy of ore particles by uniaxial compression test, and construct the cumulative probability distribution function of fracture energy;Subsequently, convert the fracture energy into specific fracture energy, and establish a crushing probability model based on lognormal distribution;Further, obtain the crushing probability data under different impact times through drop ball impact test;On this basis, introduce the cumulative damage evolution model, establish the crushing probability prediction model under multiple impact actions, and realize the inversion calibration of cumulative damage constant by minimizing the standard residual between predicted value and test value.The application can quantitatively describe the damage accumulation process of ore under repeated impact, improve the accuracy of crushing model, and provide a theoretical basis for ore crushing mechanism research and equipment optimization.

This invention discloses a method for identifying landslide risks in open-pit mines driven by the spatiotemporal distribution evolution of rock mass mechanical parameters, relating to the fields of rock mechanics and open-pit mine slope stability analysis. The main components include: constructing a spatial distribution model of rock mass using the Geophysical Indicator (GSI) based on borehole core data and geostatistical methods; measuring the physical parameters and conducting uniaxial compression tests on rock samples from the landslide area; establishing the weakening relationship of rock mechanical parameters with immersion time; calculating the degradation equations of rock mass cohesion and friction angle with immersion time and spatial coordinates based on the GSI spatial distribution model and the Hoek-Brown criterion; constructing a three-dimensional spatial distribution model of rock mass mechanical parameters considering immersion time, and performing three-dimensional numerical simulations to analyze rock mass stability and obtain low safety factors and damaged areas. This invention solves the technical problem of the inability to accurately identify catastrophic events such as landslides and collapses caused by the degradation of rock mass mechanical parameters due to the weakening of soft rock strata caused by immersion in water in existing open-pit mines.