244 results about "Triaxial shear test" patented technology

The invention relates to the technical field of mine safety monitoring, and discloses a roadway surrounding rock stability evaluation method, which comprises the following steps: step 1, collecting roadway surrounding rock geological data, step 2, constructing a three-dimensional geomechanical model, step 3, inverting mechanical parameters, step 4, calculating a stability coefficient, and step 5, outputting an evaluation result. According to the method, rock mass types, structural plane occurrence, crustal stress vectors and permeability parameters are integrally collected through geological radar scanning, drilling coring and crustal stress measuring devices, the problem of model distortion caused by single data in a traditional method is solved, deformation of a stress concentration area is accurately captured by adopting a non-uniform grid division strategy, inversion mechanical parameters are combined, and the method is suitable for large-scale popularization and application. The network is trained by using in-situ direct shear and triaxial test data, the inversion efficiency is improved compared with manual trial and error, the whole surrounding rock fracture process is simulated based on a finite element-discrete element coupling algorithm, plastic zone distribution and a comprehensive index S are output, and automatic judgment of the stability level is realized.

The invention discloses a rock mass structural plane shear degradation constitutive model under true three-dimensional stress and a numeralization method, and the method comprises the following steps: carrying out a rock mass structural plane pre-peak and post-peak cyclic loading and unloading true triaxial shear test, and obtaining the strength, deformation and damage characteristics of the structural plane; based on a test result, establishing a three-dimensional structural surface shear strength criterion considering the lateral stress effect, and proposing a calculation method of shear modulus, cohesive force, friction angle and dilatancy angle in the shear fracture process of the structural surface; constructing a three-dimensional shear degradation constitutive model considering the lateral stress and shear parameter degradation effect and a continuous and discontinuous numeralization method of the three-dimensional shear degradation constitutive model; the three-dimensional shear degradation constitutive model is verified through numerical simulation of a true triaxial shear indoor test; and carrying out excavation response analysis on the complex stratum tunnel by adopting the three-dimensional shear degradation constitutive model. The invention provides a rock mass structural plane shear degradation constitutive model and a numerical method under true three-dimensional stress, and a theoretical basis is provided for rock mass structural plane underground engineering catastrophe prediction.

The invention discloses a breakable rock-soil granular material triaxial test simulation method based on a lattice spring-discrete element coupling framework, which comprises the following steps: establishing a triaxial test model rectangular boundary condition, and generating a non-breakable spherical rock-soil granular material in the boundary; replacing the generated non-crushable spherical particle material with rock-soil particles considering particle crushing based on a lattice spring-discrete element coupling frame, and assigning parameters; replacing wall bodies on the two sides of the rectangular boundary condition with a large number of bonded spherical particles to generate a flexible membrane boundary; and applying confining pressure to the boundary of the generated flexible membrane, and carrying out shear simulation. According to the method, the Young modulus and the Poisson's ratio can be matched in a high-precision mode, the heterogeneity of elastic response is reduced, strength degradation and friction characteristics are simulated, and the calculation efficiency is greatly improved.

A true triaxial rock-soil mass test device and a test method therefor, the test device comprising a triaxial loading module, wherein the triaxial loading module comprises a triaxial servo loading system and a triaxial bearing system, the triaxial servo loading system being configured to apply an X-direction pressure, an Y-direction pressure and a Z-direction pressure to the triaxial bearing system; a grouting module, wherein the grouting module is connected to a grouting fracturing pipe (13) in the triaxial bearing system by means of a pipeline; a hydraulic cracking module, wherein the hydraulic cracking module is connected to the grouting fracturing pipe (13) in the triaxial bearing system by means of a pipeline; and a data acquisition and analysis module, wherein the data acquisition and analysis module is connected to an ultrasonic transmitting sensor and an ultrasonic receiving sensor in the triaxial bearing system by means of a line. With the test method using the test device, triaxial grouting tests and triaxial hydraulic cracking tests can be performed, a true triaxial hydraulic cracking and grouting test on a complete rock mass can be performed, and a true triaxial grouting test on a loose mass can also be performed.

The invention discloses a rock mass structural surface three-dimensional failure criterion considering a lateral stress effect and a construction method thereof. The construction process comprises the following steps: S1, carrying out a true triaxial shear test to determine peak strength of a rock mass structural surface under the combination of different normal stress sigma n and different lateral stress sigma p; s2, obtaining a shear peak strength change rule under the action of different normal stresses sigma n under true triaxial, and constructing a shear peak strength function F1 (sigma n) of the rock mass structural plane; s3, obtaining a shear peak strength change rule under the action of different lateral stresses sigma p under true triaxial, and constructing a shear peak strength function F2 (sigma p) of the rock mass structural plane; s4, constructing a shear peak intensity function F3 (sigma n, sigma p) in a three-dimensional stress state, and determining an envelope surface form of the shear peak intensity function; and S5, carrying out true triaxial shear tests on the rock mass structural surfaces with different lithology, verifying and perfecting a shear peak strength function F (sigma n, sigma p) in a three-dimensional stress state, and constructing a rock mass structural surface three-dimensional failure criterion considering the lateral stress effect.

The invention discloses a Neper-DEM-based apparent crystal rock modeling and calculation method with a bedding structure, relates to the field of numerical calculation of a tunnel engineering technology, and solves the problem that a simulation and calculation method for apparent crystal rocks with transverse isotropy such as gneiss and granite gneiss is lacked in the prior art. The method comprises the following steps: constructing a polycrystal structure with crystal characteristics in Neper, and generating a geometric parameter text of crystal grains from the polycrystal structure; constructing a discrete element rock sample model in the DEM; performing a numerical simulation test on the discrete element rock sample model to obtain a stress-strain curve and a sample failure mode, wherein the numerical simulation is realized by adopting a Brazilian splitting test and a triaxial test; according to a numerical simulation result, discrete element sample calculation parameters are calibrated, and the effectiveness of the modeling and calculation method of the discrete element rock sample model is verified; according to the modeling method, construction and assignment of the crystal structure and the bedding structure are achieved at the same time, so that the rock structure is closer to a real rock structure.

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 belongs to the technical field of rock mass performance research, and discloses a method for preparing composite rock with fractures, which comprises the following steps: transforming a cubic ABS (acrylonitrile butadiene styrene) plastic mold, and marking a groove in the center inside the mold for placing a steel plate; for a rock sample with a crack located in the middle of a similar rock, different crack inclination angles, lengths and positions are drawn through Microsoft Visio drawing software, the crack inclination angles, lengths and positions are printed, sheared and pasted to the surface of a mold to determine the positions of the cracks, thin steel sheets heated at high temperature are used for scalding and melting at specific positions of the two sides of the mold, and a reserved opening is obtained, and the steel sheets can be placed in advance before slurry is poured. The rock sample preparation process comprises the steps of mold preparation, slurry preparation, pouring and vibrating, mold removal and maintenance, core drilling and sampling, end cutting and sample polishing. The method for manufacturing the fissure-containing composite rock cylindrical standard test piece for the indoor triaxial test is convenient to operate, high in practicability and accurate in fissure positioning, and can be generally used for preparing fissure-containing composite rock samples.

The invention provides a real-time grouting device based on a true three-way three-rigidity pressure testing machine, which comprises a pressure sealing box with a rectangular structure, the pressure sealing box is formed by splicing four sealing elements, each side wall of the pressure sealing box is provided with a rigid pressing plate, the rigid pressing plate comprises a connecting pipe, and the connecting pipe is provided with a plurality of clamping grooves. A pressing plate is fixed to the inner end of the connecting pipe, a grouting pipe is arranged in the connecting pipe, a grouting hole is formed in the pressing plate, and one end of the grouting pipe is connected with the grouting hole. The device can be carried on a three-way rigid loading true triaxial testing machine to carry out a real-time grouting test, meanwhile, according to the designed test method, complete reduction and simulation of the grouting reinforcement working condition in deep engineering can be achieved, loading and grouting can be completed at the same time through the pressure head, the requirement for real-time grouting reinforcement is met, and the test efficiency is improved. The real-time grouting reinforcement mechanism of the deeply-buried engineering rock mass under the true triaxial excavation stress path change can be studied, and a theoretical basis is provided for grouting engineering design.

The invention provides a method for establishing a deep hard rock dynamic disturbance three-dimensional mechanical model, and relates to the technical field of rock mechanical properties and engineering. The method comprises the following steps: carrying out a true triaxial test without power disturbance and a true triaxial test under the action of power disturbance on a deep hard rock taken from a certain tunnel project in the deep part, and recording test data of the whole mechanical behavior process of each test; determining failure modes of the deep hard rocks under different dynamic disturbances by comparing all the tested deep hard rocks; the method comprises the following steps: determining a parameter evolution model of cohesion and an internal friction angle under the dynamic disturbance true triaxial condition by constructing a mechanical model of a deep hard rock under the dynamic disturbance true triaxial condition on the basis of mechanical behavior whole-process test data of the deep hard rock under the dynamic disturbance action and failure modes of the deep hard rock under different dynamic disturbances; according to the method, the mechanical behavior of the hard rock under the influence of multi-source dynamic disturbance can be predicted, and a basis is provided for surrounding rock stability evaluation in the construction process of a deeply-buried hard rock area.

The invention discloses a slag permeability coefficient depth distribution prediction method considering a particle crushing effect, and belongs to the technical field of rock-soil body performance prediction. According to the invention, a dynamic triaxial test is carried out on a slag sample, and the dynamic evolution law of grain composition and breakage rate of slag at different depth sites after different vibration times of loading is explored. Meanwhile, a seepage test is carried out on the slag subjected to cyclic loading and crushing through a seepage erosion simulation test device, the critical hydraulic gradient of migration and structural damage of fine particles in the slag of different grades under the seepage erosion effect is explored, the degradation and damage mechanism of the slag is revealed, and a negative index continuous grade formula is used as a hub; according to the method, a prediction model of the particle crushing index and the permeability coefficient is constructed, and the internal mechanism of the particle crushing behavior and the permeability characteristic evolution of the slag roadbed under the cyclic load effect is disclosed, so that the predicted permeability coefficient is closer to the actual permeability coefficient, and the prediction precision is improved.

The invention discloses a shear strength parameter determination method considering earthquake action, which comprises the following steps: collecting a soil sample of a research area, air-drying, dispersing the soil sample into single particles, and sieving to obtain the stone content of the soil sample; the method comprises the following steps: preparing a compacted cylindrical sample from a soil sample, and placing the compacted cylindrical sample in a triaxial testing machine for a triaxial test to obtain static strength parameters of the soil sample; collecting seismic magnitude data of the research area, and determining the seismic magnitude of the research area; and according to the stone content, the static strength parameter and the earthquake magnitude, calculating the shear strength parameter of the research area under the earthquake action by adopting a shear strength damage cracking model. Based on PFC numerical simulation software, dynamic triaxial numerical simulation of the accumulation body is carried out and compared with an indoor test result, the change rule and numerical value of the numerical simulation result are close to those of the indoor test result, the parameter error is smaller than 50%, and the reasonability of the established accumulation body sample model and the calculated dynamic strength parameters is verified.

The invention discloses a rock shear seepage coupling true triaxial test system, which relates to the technical field of rock mechanical tests, and comprises a host, a sigma 1 / sigma 2 direction loading module, a sigma 3 direction confining pressure module, a pressure chamber auxiliary system, a sample clamp, a pore water seepage system, a temperature system, a control module and a data acquisition and processing module, through servo closed-loop linkage double-pump loading in the sigma 1 / sigma 2 direction, synchronous output of the double pumps and coordination of pressure supply of the two oil cylinders by the controller, a strain correction algorithm is combined, stability of a stress loading center is guaranteed, strain measurement accuracy is improved, confining pressure is accurately controlled in the sigma 3 direction through a double-balance pressure chamber and a pressure regulation algorithm, and the stress measurement accuracy is improved. The pressure chamber is in full-automatic operation, manual steps are omitted, errors are reduced, efficiency is improved, a stress-free blank angle clamp eliminates friction interference, a seepage system supports a double-loading mode, a control module achieves multi-control-mode impact-free switching, a data processing module is combined with an elastic modulus calculation algorithm, rock mechanical parameters are accurately obtained, and the multi-field coupling test requirement is met.

The invention relates to a triaxial test universal sample preparation and high-frequency vibration loading integrated device and method, the device comprises a main body loading frame, a sample preparation suite, a loading suite and a loader, and the loader comprises a voice coil motor; the main body loading frame comprises a supporting plate, a supporting rod and a loading ejector rod, a working space is formed between the supporting plate and the supporting rod, one end of the loading ejector rod is connected with the loader, and the other end of the loading ejector rod extends into the working space; a soil sample is placed in the sample preparation suite, and the loading ejector rod loads static force or surface vibration to the sample preparation suite; a sample prepared in the sample preparation suite is placed in the loading suite, and the loading ejector rod loads static force or power to the loading suite. Compared with the prior art, the sample preparation and loading of the triaxial test sample are realized through the sample preparation suite and the loading suite, and the operation is convenient; and the loader adopts electric loading, so that the problems of compactness, stable quality and the like during sample manufacturing can be solved, and the test error can be effectively reduced while manpower is saved.

The invention provides a high-stress rock mass disturbance catastrophe real-time early warning method based on a fracture comprehensive signal, which belongs to the technical field of geotechnical engineering, and constructs a comprehensive acoustic parameter ASCP by fusing various parameters such as amplitude, dominant frequency, energy distribution, crack fractal characteristics, rock mass fracture event density and the like in an acoustic emission signal. The calculation process is combined with contribution weights of different parameters to the destruction stage, and weight values are jointly calibrated through data analysis. On the basis of a large amount of engineering field monitoring and indoor true triaxial test data, the evolution law of the ASCP in the rock mass damage process is analyzed, multiple early warning thresholds of an ASCP evolution curve starting early warning threshold and an ASCP catastrophe early warning threshold are provided, and the early warning accuracy and timeliness are improved. According to the early warning method, various parameters of sound signals are integrated, a multi-threshold early warning method is established, the contribution degrees of various main sensitive parameters of high-stress rock mass disturbance damage sound emission are integrated, and the early warning accuracy, timeliness, high efficiency and economical efficiency are improved.

The invention provides a high-temperature and high-pressure rock triaxial and hydraulic fracturing test system capable of loading a plurality of samples in different bins, which comprises a fracturing test bin arranged in a thermal insulation bin, a computer display, control and storage system is arranged outside the fracturing test bin, and the fracturing test bin is controlled by signals of a high-temperature heating and control system, an axial pressure loading and control system, a confining pressure loading and control system, a fracturing fluid injection pump and a control system; the computer display, control and storage system is respectively in communication connection with the high-temperature heating and control system, the axial pressure loading and control system, the confining pressure loading and control system, the fracturing fluid injection pump and control system as well as an acoustic emission monitoring system and an injection pressure monitoring system which are arranged in the fracturing test bin; the fracturing test cabins are arranged in different cabins; the system comprises a high-temperature and high-pressure triaxial test method and a high-temperature and high-pressure hydraulic fracturing test method. The device has the advantages that the test efficiency is improved, the test period is shortened, a plurality of rock core samples can be tested at the same time, and a visual contrast test can be formed.

The invention relates to a method for simulating a complex earthquake load in a triaxial test, and belongs to the field of geotechnical engineering indoor test methods. The invention mainly overcomes the defects in the prior art, and provides a simulation method for complex earthquake load in a triaxial test, which comprises the following steps: acquiring a near-field strong earthquake record, and carrying out baseline correction and filtering processing on the near-field strong earthquake record; decomposing and synthesizing the near-field strong earthquake record; performing time-history conversion on the near-field strong earthquake record, and determining experimental parameters; preparing a soil-rock mixture sample, and saturating the sample; performing an indoor triaxial test on the saturated sample according to the determined experimental parameters; calculating the correlation between the input waveform and the output waveform according to the test result; and analyzing typical dynamic characteristics of the soil-rock aggregate under the action of the near-field strong earthquake according to a test result. The invention provides a method for analyzing test data under the action of earthquake load, and provides an indoor triaxial test method for carrying out research on dynamic characteristics of a rock-soil body by near-field strong shock of an active fault zone.

The invention discloses a practical method for calculating additional settlement of a foundation by considering a'pot cover effect ', and relates to the technical field of geotechnical engineering.The method comprises the steps that the increment of the moisture content and the suction variation of soil bodies with different depths caused by the'pot cover effect' are calculated; unsaturated soil model parameters are constructed through an indoor triaxial test; and with the UH constitutive model of the unsaturated soil as a core, performing foundation settlement calculation based on a layering sum algorithm. According to the method, the suction variation of soil bodies with different depths is calculated, soil property parameters determined by indoor tests are combined, an unsaturated soil UH constitutive model is taken as a core, and a calculation method for the additional settlement of the foundation correctly reflecting the influence of the pot cover effect is established on the basis of a layering sum algorithm; practical calculation of foundation additional settlement caused by the pot cover effect is achieved for the first time.

The invention relates to a pressure freezing triaxial test device and method for a rock-soil medium, and belongs to the technical field of rock-soil pressure freezing experiments. The device comprises a pressure bearing mechanism, a triaxial loading control mechanism, a confining pressure loading mechanism, a freezing mechanism and a stress and deformation monitoring mechanism, and can realize accurate control of confining pressure, axial load, pore water pressure and temperature of a sample; through the CT imaging unit, the change of the rock and soil medium in freezing and triaxial loading processes can be monitored in real time. The method comprises the steps of sample placement, CT imaging, confining pressure control, pore water pressure adjustment, axial load application and stress deformation monitoring so as to analyze the mechanical property of the rock and soil medium. According to the invention, the change condition of the rock-soil medium in freezing and triaxial loading processes can be obtained in real time, and a test means is provided for the research of the mechanical properties of underground frozen rock-soil.

The invention provides a triaxial test soil sample preparation device capable of simulating sedimentary stratification distribution and a preparation method. The preparation device comprises a rack, a sample compaction cylinder, a stratification positioning assembly and a pressurization assembly, the sample compaction cylinder is provided with a through chamber for accommodating a sample; the bedding positioning assembly comprises a bedding thickness control rod, a first pressing die and a second pressing die. The first pressing die and the second pressing die are provided with extrusion faces matched with each other. The first pressing die and the second pressing die at least comprise a plurality of replaceable pressing dies with different inclination angles and are used for controlling different bedding angles; in the state that the sample bedding is pressed, the bedding thickness control rod and the pressurizing assembly are installed on the two sides of the cylinder body respectively and fixedly arranged with the rack, the first pressing die is fixedly installed at the tail end of the bedding thickness control rod, and the second pressing die is installed at the end, facing the pressurizing assembly, of the cylinder body. Or the second pressing die is fixedly installed at the movable end of the pressurizing assembly, and at least one of the first pressing die and the second pressing die can stretch into the cylinder body.

The invention relates to the technical field of rock indoor loading tests, in particular to an intelligent true triaxial mechanical test system and method based on parameter self-adaptation, and the method comprises the following steps: S1, testing a known rock sample based on known test data, historical parameter data, historical operation data, historical experiment data and rock characteristic data of the rock sample are obtained; s2, marking corresponding time points for the historical parameter data and the historical experiment data based on the operation time data to obtain a parameter subset and an experiment subset; s3, analyzing the parameter subset and the experiment subset to obtain an intervention relation; s4, determining a data relationship between the rock characteristics and test parameters of true triaxial test equipment to obtain a basic parameter relationship; s5, testing and data monitoring are carried out on a rock sample to be tested, rock experiment data are obtained, judgment and self-adaptive parameter adjustment are carried out based on the intervention relation, and the reliability and accuracy of a test result are guaranteed while the analysis rate is increased.

The invention discloses a true triaxial test device and test method capable of realizing arbitrary rotation of principal stress, and belongs to the technical field of geotechnical engineering.The true triaxial test device comprises a shear stress device, the shear stress device comprises a shear stress pressure head used for being connected with the surface of a sample, and the shear stress pressure head is connected with two shear stress applying systems; the shear stress applying system applies shear stress parallel to the surface of the sample to the sample, and the directions of the two shear stresses are vertical; the main stress device is connected with the shear stress pressure head, and the main stress device applies pressure perpendicular to the surface of the sample to the sample. According to the invention, random rotation of the principal stress can be realized through the shear stress device, so that the direction and size of the principal stress applied to the rock sample can simulate a real path to continuously change, and the deformation fracture behavior in the rock mechanical bearing process can be more accurately obtained; and a technical support is provided for correctly and accurately evaluating the bearing characteristic, the fracture characteristic and the instability mechanism of the rock.

The invention relates to the technical field of geotechnical engineering intelligence, in particular to a multi-field coupling intelligent triaxial test method and system combined with machine learning, and the method comprises the following steps: initializing a test device, and establishing a material parameter prior distribution function; defining a target test path and obtaining a target control sequence; acquiring real-time test data through a multi-source fusion sensing array, and preprocessing the real-time test data to obtain multi-dimensional feature fusion data; establishing an online parameter identification module to obtain real-time correction material parameters; establishing a heat-water-force multi-field coupling prediction model to obtain an optimal control sequence; acquiring latest test data, and performing rolling optimization on the model to establish a lightweight control model; and generating an intelligent control instruction to realize self-adaptive intelligent control of the triaxial test. According to the invention, through combination with machine learning, the spanning of the triaxial test from experience control to intelligent control is realized, and an intelligent technical means is provided for the research of the multi-field coupling characteristic of the geotechnical material.

The invention discloses a visual seepage test device and method for shear fracture of a rock structural surface under true triaxial. The visual seepage test device comprises a fixed base, a lower shear box, an upper shear box, a seepage water inlet pipe, a seepage water outlet pipe, a seepage water inlet shear head and a seepage water outlet shear head, the fixed base is connected with a normal loading block of a true triaxial testing machine through pin nails, the lower shear box is fixed on the fixed base, the upper shear box and the lower shear box are oppositely arranged, and the seepage water inlet shear head and the seepage water outlet shear head are respectively embedded into the lower shear box and the upper shear box to form a water injection cavity I and a water injection cavity II; after the lower shearing box and the upper shearing box are closed, a closed sample cavity for clamping a rock sample and a transparent block is formed, and meanwhile, the water injection cavity I and the water injection cavity II form a seepage cavity. According to the device and the method, the visual shear simulation of the rock mass structural surface under the multi-field coupling environment of true three-dimensional stress-high osmotic pressure-chemical corrosion and the like is realized.

The invention relates to the technical field of rock mechanics true triaxial tests, in particular to a rock cylinder sample true triaxial test analysis method which comprises the following steps: applying a point load to the cylindrical surface of a cylinder sample, performing integration by using a linear superposition principle, and calculating an analytical solution of an internal stress field in the circular surface of the rock cylinder sample; applying a symmetry plane load to the cylindrical surface of the cylinder sample, and calculating an internal stress field of the circular surface of the cylinder sample under the symmetry plane load by using an analytical solution; setting a constraint condition of a stress state similar region, calculating a relation function between symmetrical surface loads in a corresponding loading mode, and determining the relation function as a linear gradient loading mode; and performing finite element analysis on the cylindrical sample of the rock, and verifying the feasibility of the linear gradient loading mode determined by the analytical solution. According to the invention, true triaxial test analysis of the cylinder sample is realized, the internal stress state of a larger area of the sample is ensured to be similar, and the problems of boundary effect, friction effect, fluid channeling and the like of a cubic sample are avoided.

The invention belongs to the technical field of geotechnical engineering and rock mechanics testing, discloses a stress-strain mixed control-based rock stable failure testing method, and aims to solve the problem that a stress path cannot be maintained and brittle failure cannot be inhibited simultaneously after rock peak strength is detected in an existing true triaxial test. The method comprises the following core steps: firstly, determining a target stress state and a strain growth rate threshold value; then hydrostatic pressure loading is carried out; loading and unloading at a fixed proportional rate in a stress control mode; and when the strain rate reaches a threshold value, switching to a stress-strain hybrid control mode, converting the maximum principal stress direction into strain control to stabilize the damage process, and dynamically coordinating stresses in the other two directions based on real-time feedback to enable the whole damage process to maintain a preset stress path all the time. According to the invention, the complete and stable test of the pre-peak-post-peak mechanical behavior of the rock under any complex stress state can be realized, and a key technical support is provided for accurately verifying the strength criterion and researching the failure mechanism.

The utility model provides a triaxial test sample preparation device suitable for calcareous sand, and belongs to the technical field of geotechnical engineering experiments. The device comprises a mounting seat, a sample preparation mold, a feeding mechanism and a vibrating mechanism. The mounting seat comprises a bottom plate and a bracket arranged on the bottom plate; the sample preparation mold comprises a sample preparation barrel and a base, the base is arranged on the bottom plate, the axis of the sample preparation barrel is perpendicular to the bottom plate, and one end of the sample preparation barrel is detachably connected to the base; the putting mechanism comprises a putting funnel; the putting funnel is connected with the bracket and is arranged above the sample preparation barrel; the vibrating mechanism is arranged on the bottom plate and comprises a motor, a transmission mechanism and a knocking ring, the knocking ring sleeves the outer side of the sample preparation barrel, a knocking block is arranged on the inner ring of the knocking ring, and the motor is in transmission connection with the knocking ring through the transmission mechanism. By adopting the triaxial test sample preparation device, the technical problem that a prepared sample is easy to deform and collapse due to the defects of a compaction mode in the prior art can be solved.

The invention relates to the technical field of data analysis, in particular to a rock shear strength prediction method and system based on an improved machine learning algorithm. The invention discloses a rock shear strength prediction system based on an improved machine learning algorithm. The rock shear strength prediction system comprises a data acquisition module and a rock shear strength analysis module. According to the method, the shear strength of the rock is predicted through the longitudinal wave speed, the density, the uniaxial compressive strength and the uniaxial tensile strength which are easy to obtain, complex work of a triaxial test can be not needed, a physical embedded input layer is arranged in a set rock shear strength analysis model, input features are expanded through priori knowledge of a physical rule, and the shear strength of the rock is predicted. The problem of low prediction accuracy caused by data sparsity is solved, so that the prediction is more accurate; and a knowledge enhancement adjustment layer is also arranged, and feature enhancement is carried out by taking rock shear strength prediction modes in different scenes as priori knowledge, so that the accuracy of rock shear strength prediction can be improved on the premise of interpretability.

The invention relates to the field of geotechnical engineering, in particular to an undisturbed soil body sample saturation method and application of the undisturbed soil body sample saturation method in an indoor triaxial test, according to the method, light white oil W2-40 is adopted as a saturation material to replace pure water for soil body saturation, the basic physical index of the light white oil W2-40 is close to the index of the pure water to the maximum extent, and the light white oil W2-40 can be used for soil body saturation. And in the aspect of chemical property, chemical reaction with various inorganic matters / polar molecules in the soil body is avoided, so that the problem of structural damage of the soil body can be fundamentally solved, and the most real strength index can be obtained through an indoor triaxial test for guiding engineering application. And the light white oil W2-40 has no danger and is high in operability.

This invention discloses a temperature-compensated seepage-shear coupling true triaxial testing apparatus and control method. The apparatus includes a pressure chamber, a shear box, a temperature control system, a pressure application system, and a temperature-displacement corrector. The shear box is housed within the pressure chamber. The temperature control system includes a heat transfer jacket, multi-point thermometers, and a temperature controller. The heat transfer jacket is fitted over the shear box, and the multi-point thermometers are located within the cavity. The pressure application system includes a confining pressure loading device, a pressure head, and a pressure controller. The confining pressure loading device injects a confining pressure medium into the pressure chamber, and the pressure head applies a force to the shear box. The temperature-displacement corrector is electrically connected to the temperature control system and the pressure application system. This apparatus features a temperature control system to precisely regulate the temperature during the test, thereby simulating deep environments at different temperatures. Furthermore, the temperature-displacement corrector dynamically corrects the force applied by the pressure application system, reducing additional forces caused by thermal expansion or contraction and improving stress control accuracy.