338 results about "Uniaxial compression" patented technology

A uniaxially compressed dosage form manufactured by three-dimensional printing that preserves the predetermined internal architecture of the dosage form while producing an improved surface finish. The compression compacts the dosage form, eliminating at least some of the void space that remains at the end of conventional three-dimensional printing. Surface finish obtained as a result of the uniaxial compression process can be essentially equal to that obtained from conventional tablet pressing. Additionally, the internal structure or spatial variation of composition of the dosage form is preserved during the pressing operation, with geometric shrinkage occurring mostly in the direction of the axis of pressing. Further, as a result of compression, a greater quantity of API can be packed into a given final volume of dosage form.

The invention provides a method for confirming the anisotropism of jointed rock mass. The method comprises the following steps of: firstly building the multi-scale jointed rock mass capable of sufficiently reflecting the rock mechanical property, the joint mechanical property and the joint spatial distribution characteristic, wherein the jointed rock mass with different scales comprises three groups of samples, and the long axial directions of the samples are respectively along the X-direction, the Y-direction and the Z-direction; carrying out virtual uniaxial compression loading along the long axial directions of various kinds of jointed rock mass to obtain a stress-strain curve, and extracting the mechanical parameters of the jointed rock mass along the X-direction, the Y-direction and the Z-direction, i.e. the uniaxial compressive strength, the elasticity modulus and the like; and building an anisotropism index Ksi, and confirming the anisotropism of the mechanical parameters of the jointed rock mass along the different axial directions, i.e. the uniaxial compressive strength, the elasticity modulus and the like under different scales, so that the anisotropic characteristics of the jointed rock mass can be quantitatively researched. The invention provides a method which is simple in principle, convenient to operate, low in cost and good in use effect, so that the anisotropic characteristics of the jointed rock mass can be confirmed.

The expandable jacket consists of the rubber membrane surrounding the cylindrical specimen, circular segmental metal plates surrounding the rubber membrane, and elastomeric rubber bands or rings around the segmental plates to permit uniform radial expansion and maintain uniform diameter of the specimen during the test and thereby providing accurate values of deviator stress, volume change characteristics and shear strength of soil specimen. To determine the three-dimensional coefficient of consolidation and coefficient of consolidation in horizontal direction, the flexible ring consists of all above structural components of expandable jacket except that a filter fabric or paper is wrapped around the cylindrical specimen, and then rubber membrane is mounted surrounding the filter paper or paper. The calibration device for calibration of the expandable jacket and flexible ring shall provide the magnitude of correction to be made in deviator stress and lateral resistance provided by the rubber bands or rings during the test.

The invention discloses a rock property test system, which comprises a rock microscopic optical tester. A fully saturated sample is placed on the rock microscopic optical tester, and the surface of the fully saturated sample is provided with an acoustic emission test system and a resistivity test system. Specifically, a rock damage evolution test method includes the steps of: 1. connecting the rock microscopic optical tester with the acoustic emission test system and the resistivity test system in parallel; 2. assembling a rock property test system; 3. performing uniaxial compression test and observing the correlation of the rock's wave electric field parameters and strain under a loaded condition; 4. quantitatively describing the appearance and internal injury of the rock at each loading stage under a load-bearing condition; and 5. at each stage of uniaxial compression damage evolution, employing different damage variables to describe the rock damage evolution process. The system and the method provided by the invention can realize whole course observation of the whole process of the rock internal and external damage rupture, and overcomes the restriction of traditional testers on the sample shape.

The invention discloses a manufacturing method of a rock-internal-crack-simulated expansion transparent material, which comprises the following steps: manufacturing a mold, manufacturing a prefabricated crack, manufacturing a mixed solution, carrying out repeated baking and refrigeration on the solidified specimen, and the like to finally obtain the rock-internal-crack-simulated expansion transparent material. The manufacturing method is convenient to operate; the experiment testing proves that various properties of the manufactured rock-internal-crack-simulated expansion transparent material are approximate to those of rock, and the rock-internal-crack-simulated expansion transparent material satisfies the two most important properties (brittleness and expansion due to shear under monoaxial compression conditions); and the method can solve the problem that the rock internal crack can not be visually observed in deed, and has important practical meanings for researching the true rock internal crack expansion perforation mechanism.

The invention discloses a sensor fixing test rack for a uniaxial compression sound emission test of coal petrography and an application method of the sensor fixing test rack. The test rack comprises a round rack in which a coal petrography sample is arranged, and three foot stools distributed at 120 degrees and used for fixing the round rack, wherein clinging devices used for fixing sound emission sensors in contact with the coal petrography sample are arranged on the round rack; the round rack comprises an upper round rack and a lower round rack which are respectively fixed with the upper parts and the lower parts of the three foot stools; the plurality of clinging devices are respectively fixed on the upper round rack and the lower round rack. When in use, the sensor fixing test rack is placed on a uniaxial compression tester; a coupling agent is uniformly applied on the surfaces of the signal acquisition ends of the sound emission sensors; after the sound emission sensors are mounted, the coal petrography sample is placed, and then the uniaxial compression sound emission test can be performed. The sensor fixing test rack solves the problems that at present, when the uniaxial compression sound emission test is performed in a laboratory, the spatial position of the sensors can not be fixed accurately, the sensors drop in the testing process, and high labor intensity is caused by repeated disassembly and assembly of the sensors.

The invention discloses an assembled size-changeable double-face shear apparatus for performing a direct shear test on various size-changeable rock test samples. An upper shear box, a lower shear box and a middle shear layer are assembled size-changeable test sample box sleeve pieces consisting of stacked test sample box rigid components; each test sample rigid component comprises a plurality of embedded sample accommodating rings; the inner side sample accommodating rings is axially limited by the outer side sample accommodating rings in one direction; the rigid components forming the upper shear box and the lower shear box respectively are anchored together; rolling supporting matched structures are arranged on the outmost side sample accommodating rings of the rigid components in the upper shear box and the lower shear box; water drainage slots are formed in the sample accommodating rings at the bottom of the lower shear box; and the water drainage function is shut down according to a test requirement. The assembled size-changeable double-face shear apparatus can perform the double-shear-face direct shear test on a soil sample and soft rock, and a lateral-restrict-free single-shaft compression test on hard rock is easy to operate, convenient to maintain and detachable, has high environmental adaptability, and is suitable for being used in indoor and outdoor rock direct shear compression tests.

The expandable jacket and flexible ring comprises of the segmented circular arch shaped plates and bands or rings around the segmented plates. The test preparation consists of a membrane surrounding a specimen with or without a filter, segmented plates surrounding the membrane, and bands or rings around the segmented plates to permit uniform radial expansion of the specimen through its height when increments of vertical load are applied during the test, thereby providing accurate values of area of cross-section, deviator stress, volume change, modulus of elasticity, Poisson's ratio and shear strength. Using the flexible ring, three-dimensional consolidation tests are performed to determine three-dimensional coefficient of consolidation and coefficients of consolidation in horizontal and vertical directions. Removable attachments are used for assembling the expandable jacket and flexible ring during the test. A calibration device is used to determine the modulus of elasticity of the membrane and expandable jacket and flexible ring.

The invention provides a computing method for the representative elementary volume of a jointed rock, which belongs to field of geotechnical engineering calculation parameters. According to the invention, a multi-scale jointed rock sample with an indoor test scale, an on-site in-situ test scale, an engineering scale and the like capable of fully reflecting joint spatial distribution characteristics and rock and joint mechanical characteristics is constructed based on indoor rock and joint mechanical tests and on-site joint geological survey, and virtual uniaxial compression loading is carried out on the sample to obtain a stress-strain curve; a relational graph of uniaxial compressive strength of a variety of jointed rocks and loading-direction sample dimension is drafted, and a relation curve is fitted; in the fitted relation curve, if a ratio of reduction amount of the uniaxial compressive strength to uniaxial compressive strength of an indoor rock sample is less than 0.2% when the loading-direction sample dimension of the jointed rocks is increased by 1 m each time, it is believed that uniaxial compressive strength of the jointed rocks does not change with increase of dimension, and the representative elementary volume of the jointed rocks is obtained. The method provided by the invention has the advantages of simple principles, convenient operation, low cost and a good usage effect and facilitates determination of the representative elementary volume of the jointed rock.

The invention discloses a temperature-controllable rock uniaxial compression sound emission test device and a temperature-controllable rock uniaxial compression sound emission test method. The test device comprises a loading system, a heating system, a temperature control system, a strain system and a sound emission system, wherein the heating system, the temperature control system, the strain system and the sound emission system are all arranged on the loading system. According to the test method, a rock sample is arranged inside a soft shell, heating resistance wires are distributed around the outside of the shell, and a temperature sensor, radial and axial strain gauges and a sound emission sensor are arranged, so that the uniaxial compression multi-channel sound emission detection test can be implemented. According to the test device and the test method, the sound emission detection of the rock sample under different temperature environment influences can be simulated. The test device has a simple structure, is convenient to operate and can be used for simulating the sound emission detection demands of rock materials under different temperature environments indoors.

A fixing device for an acoustic emission sensor used in a rock triaxial test under the confining pressure condition is suitable for an indoor acoustic emission test on the rock damage mechanism, damage positioning and accumulation process in conventional rock triaxial and uniaxial compression tests. The fixing device comprises a fixing ring, a pretensioning mechanism and an acoustic emission sensor sealed chamber, wherein the fixing ring is hinged with the pretensioning mechanism through bolts; the acoustic emission sensor sealed chamber comprises a sealed cylinder body with a guide groove and acoustic emission sensors arranged in the sealed cylinder body, and a wire outlet into which a bonding steel structured glue is injected is formed in the side wall of the sealed cylinder body; and the pretensioning mechanism comprises springs and adjusting bolts, through which a plurality of arc-shaped pretensioning steel sheets are connected into a circular ring. The fixing device can effectively protect the acoustic emission sensors and prevent the acoustic emission sensors from damage and destroy under high oil pressure without influencing original measurement equipment, ensures that an acoustic emission monitoring system is always in close contact with a rock sample, remarkably reduces interference signals in the acoustic emission test, and satisfies the acoustic emission test requirement in the rock material damage process.

The invention discloses an impact damage rock sample preparation and assay method based on an SHPB test and belongs to damage rock sample preparation and assay methods. The method comprises the steps that firstly, a cylindrical rock sample is manufactured, an SHPB device is used for conducting impact pre-damage on the cylindrical rock sample at an air pressure value lowered than the critical air pressure, corresponding stress waves are recorded, and the dynamic strain peak value, the strain rate peak value and the unit volume absorbing energy are acquired through calculation; secondly, the circle center of the end face of the rock sample serves as a center point, and axial drilling is conducted to form a cylindrical standard damage sample; thirdly, macro and microscomic testing of CT scanning, nuclear magnetic resonance, a longitudinal wave speed, a permeability coefficient, elasticity modulus, uniaxial compression strength and the like is conducted on the standard damage rock sample; fourthly, the same macro and microscomic testing is conducted on standard complete rock samples with the same rock character and physical parameters; fifthly, the dynamic damage degree of the impact to the rock material is quantitatively judged with the dynamic strain peak value, the strain rate peak value, the unit volume absorbing energy and other impact effect parameters as the bases by combining the data of the macro and microscomic testing. The method has the advantages that operation is easy, and the test data are comprehensive and reliable.

The invention discloses a brittle material crack initiation stress measurement system and a brittle material crack initiation stress measurement method. The brittle material crack initiation stress measurement system comprises a loading device, a CCD camera, a synchronizer trigger, a load-time signal receiving device and a digital image signal receiving device. The brittle material crack initiation stress measurement method includes synchronously triggering the loading device and the CCD camera by the synchronizer trigger, loading a sample and outputting a load-time signal; shooting sample surface images by the CCD camera in real time; not stopping shooting until the sample is destroyed; selecting a first frame of images shot by the CCD camera, marking 2 measurement points on the circumference of a through hole, continuously measuring tensile strain-time curves of the 2 measurement points in a whole loading process, and determining stress values, namely crack initiation stress sigmaci,on the stress-time curves corresponding to tensile crack initiation time T. The brittle material crack initiation stress measurement system and the brittle material crack initiation stress measurement method have the advantages that the position and the expansion direction of brittle material crack initiation can be controlled, the crack initiation time and the crack initiation stress can be determined objectively, precisely and quantitatively, authenticity and reliability of brittle material crack initiation stress measurement are improved effectively, and the method simple to operate, reliable in result and objective in quantization is provided for measuring crack initiation stress of rock-like brittle materials with prefabricated holes under uniaxial compression.

The invention discloses a uniaxial compression creep test method for a saturated and unsaturated rock-soil body, which is characterized in that the uniaxial compression creep test for the rock-soil body is carried out by a device. The device mainly comprises a water tank (1), a pressurized framework (2), a dial indicator (4), a pressure chamber (5), a water inlet pipe (6), a water outlet pipe (8), a pressurized shaft (11), an upper drain pipe (12), a water conduit (14), a drift cap (15), an upper porous stone (16), a lower porous stone (18), a base (19), a water measuring pipe (20), a lower drain pipe (23), a pressure chamber base (24), a dead bolt (25), a weight (26), a pressurized lever (30) and the like. The instrument has the advantages of simpleness in manufacture and high measurement precision, can be used for directly measuring the long-term creep compressive strength and the deformation parameter of various soft rocks and hard soils under the saturated and unsaturated condition, and can be used for the indoor and field tests for various soft rocks and hard soils in the civil engineering. The test method is mainly divided into three steps of installing a test sample, making a water filling preparation and loading the test sample.

The invention discloses a grading optimization method for an asphalt mixture under virtual state. The method includes the steps of: on the basis of grading that needs to optimize according to practical demand, in three-dimensional discrete element software PFC3D, randomly generating an asphalt mixture mechanical test three-dimensional discrete element model (including uniaxial penetration test, low temperature split test, uniaxial compression test and shear fatigue test) which satisfies a target grading, wherein the generation process of the three-dimensional discrete element model, which satisfies the target grading, is the base of asphalt mixture grading optimization; and comparing mechanical performance evaluation results of various grading to obtain a grading having best mechanical performance. The method has strong operability, convenience and representativeness.

The invention discloses a device and a method for monitoring rock sample damage in the uniaxial compression process, which has the benefits that the joint real-time monitoring of acoustic wave, acoustic emission and electromagnetic radiation information in the uniaxial compression test process of a rock sample is realized; based on the three measurement data, different damage variable expression forms are respectively defined; on the basis of fully considering the acoustic wave velocity, acoustic emission and electromagnetic radiation variation law complementarity of the rock sample in the uniaxial compression process, a more reasonable comprehensive damage variable is provided to comprehensively and completely reflect the damage states of the rock sample at different damage stages; compared with a conventional electromagnetic measurement probe, an electromagnetic radiation measuring coil is simpler and more convenient to manufacture and can effectively shield the interference generated by ambient electromagnetic radiation noise, so that measurement results are more accurate; as the total number of turns of leads is changed, and the leads at positions with different numbers of turns are led out outwards and are respectively connected with a plurality of channels of an electromagnetic radiation detector, the simultaneous measurement of electromagnetic radiation signals within different frequency band ranges can be quickly and conveniently realized.

The invention discloses a laterally constrained rock uniaxial compression test device. An annular hollow cylindrical lateral confinement compression chamber is formed by two semi-cylindrical shells with the same shapes, screw holes are formed in the edges of the two semi-cylindrical shells, bolts penetrate through the screw holes to fix the two semi-cylindrical shells to form a hollow cylinder, the upper part and the lower part of the annular hollow cylindrical lateral confinement compression chamber are open, a T-shaped bearing plate is arranged on the upper opening, the T-shaped bearing plate is provided with a cylindrical heave to extend into the inner part of the annular hollow cylindrical lateral confinement compression chamber, the lower part of the annular hollow cylindrical lateral confinement compression chamber is arranged in a T-shaped port of the T-shaped bearing plate, two strain pieces are respectively installed on the surface of the two semi-cylindrical shells of the annular hollow cylindrical lateral confinement compression chamber, and the strain pieces are respectively connected with external resistance-type strain gages by leads. The invention provides the laterally constrained rock uniaxial compression test device, and uniaxial compression test of a rock sample can be carried out under annularly constrained condition by utilizing the device.

The invention discloses a method for obtaining the rock micrometer-scale elasticity modulus and yield strength. The method comprises the steps that a rock micrometer indentation experiment is carriedout through a micron-sized pressure head, a load-displacement curve in the loading process is obtained, and the rock elasticity modulus under different displacement conditions can be obtained by combining an indentation experiment formula; micro-CT scanning is carried out on a rock sample, and a finite element mesh model of a rock skeleton in an indentation area is built; the elasticity modulus obtained through the micrometer indentation experiment serves as an input parameter to simulate the rock uniaxial compression process, the model overall elasticity modulus is obtained and compared witha rock core uniaxial compression experiment, and the pressing depth RVE effectively representing the rock micrometer elasticity modulus is determined; and then, rock sample indentation experiment numerical simulation under different yield strength conditions is carried out, the simulated loading and unloading load-displacement curve is compared with the indentation experiment to be verified, and thus the rock micron-sized yield strength is determined.

The invention discloses a device and a method for measuring the heat conductivity coefficient reduction rate of concrete in a uniaxial compression process. A concrete test sample is put into a bracket to be subjected to a compression load, and meanwhile a heating unit and a refrigerating unit establish a temperature difference between two planes of the concrete test sample; the bracket is used for fixing relative positions of the concrete test sample with the heating unit, the refrigerating unit, a heat insulating material and heat conduction silica gel; the concrete test sample is deformed under pressure, and extrudes the heat insulating material, the heat conduction silica gel, the refrigerating unit and the heating unit in order that the heat insulating material, the heat conduction silica gel, the refrigerating unit and the heating unit move outwards towards the periphery; peripheral support posts of the bracket are used for determining moving tracks of peripheral materials; spring pressing plates and springs on the support posts provide a proper peripheral pressure not influencing mechanics experiments in order to ensure that the refrigerating unit and the heating unit fit the surface of the concrete test sample, thereby reducing a contact thermal resistance as much as possible. Under the situation that the concrete test sample is under a certain compression load, a thermal flow density inside the concrete test sample reaches a steady state, and the temperature is distributed stably in a one-dimensional form in the concrete test sample.

The invention relates to the field of rock performance tests, in particular to a method for determining the fracture closure stress of a rock under the uniaxial compression condition. The method comprises the following steps: a, processing a rock sample; b, mounting the rock sample on a sample table of a pressure machine; c, uniaxially loading the sample according to a load control mode until the sample is damaged; d, calculating the volume stress of the sample; e, determining the fracture damage intensity in a volume stress-axial stress curve; f, determining a fracture damage intensity point in an axial stress-axial stress curve, and connecting the point with a zero point to form a reference line; g, calculating the difference between the stress value on the axial stress-axial stress curve and the stress value corresponding to the reference line under the same stress level from the beginning of the zero point to the ending of the fracture damage intensity; h, drawing a relational scatter diagram of the axial strain difference and the axial stress, wherein the stress corresponding to the peak value of the axial strain difference is the fracture closure stress of the rock. The method is applicable to rock mechanics tests in the service of underground construction.