84 results about "Triaxial compression" patented technology

The invention relates to a method, a device and equipment for analyzing in-situ formation fracture porosity of mixed rock. Comprising the steps of obtaining original data of a plurality of layers in a target block; taking out a first rock core sample from each layer of the target block, and performing experimental analysis on the first rock core sample of each layer to determine a target layer; taking out a second core sample from the target horizon, and performing a triaxial compression test on the second core sample to obtain a stress index; according to the original data and the stress index, the stratum fracture porosity of the target layer is calculated, the stratum fracture porosity is used for guiding workers to evaluate the real underground in-situ fracture porosity of the reservoir, and therefore an oil and gas reservoir exploitation plan of the target layer is made. The stratum fracture porosity calculated by the method represents the fracture porosity of the target horizon in the target block and represents in-situ characteristics in the stratum, so that the accuracy of reservoir evaluation is improved. A worker can formulate an oil and gas reservoir exploitation plan according to the formation fracture porosity, and the oil and gas reservoir yield is improved.

The invention discloses a deep shale brittleness evaluation method based on energy evolution, electronic equipment and a medium. The method comprises the following steps: collecting basic parameters of a target stratum, and determining key parameters; carrying out a total stress-strain triaxial compression experiment according to the key parameters to obtain a total stress-strain curve of the rock core; dividing the total stress-strain curve, and respectively calculating the strain energy density related to the rock; and calculating the mineral brittleness index of the rock according to the key parameters and the strain energy density. According to the method, mineral components and energy evolution in the whole rock deformation-damage process are considered at the same time, and the brittleness characteristics of deep shale can be better reflected.

The invention belongs to the technical field of rock mechanical property research, and discloses a rock elastic-plastic damage constitutive model establishment method considering freeze-thaw strength and compaction effect, and the method comprises the following steps: proposing a concept of freeze-thaw strength to comprehensively reflect the freeze-thaw damage degrees of rock at different freeze-thaw temperatures and durations; performing a freeze-thaw test and a triaxial compression test on the rock test piece, recording test data in the triaxial compression test process, drawing a stress-strain curve based on the test data, and constructing a yield function and a hardening rule of the rock test piece based on the strength characteristic parameters of the freeze-thaw rock; establishing a rock elastic-plastic damage constitutive equation considering the freeze-thaw effect and the compaction effect; and determining a parameter expression of the rock elastic-plastic damage constitutive model based on an elastic-plastic theory in combination with freeze-thaw rock triaxial compression test data. According to the technical scheme, the compaction stage and the volume deformation of the frozen-thawed rock can be reflected, and the method has the advantages of being wide in application range and high in prediction precision.

The present invention provides a method for designing a dynamic and static universal loading path for true triaxial mechanical tests. The loading path design is carried out in the stress space. The principal stress space is sliced into a set of stress meridian plane spaces, realizing the conversion from a three-dimensional design environment to a two-dimensional design environment. Based on the above two-dimensional design environment, the dynamic and static universal loading paths under three different loading modes of triaxial compression, triaxial tension, and tension-compression compound are designed respectively. The design results in the two-dimensional design environment are converted into three-dimensional final design results. It can make the results of dynamic and static true triaxial mechanical tests comparable. The distribution of the dynamic and static true triaxial mechanical test loading paths in the stress space can be set as needed.

The invention relates to the technical field of oil and gas well wall stability and fracturing yield increase development, in particular to a deep high-temperature rock statistical damage constitutive model construction method which comprises the following steps: performing mineral component and microstructure analysis on a deep rock core by adopting XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscope) technologies, and performing quantitative statistics on mineral content to obtain a deep high-temperature rock statistical damage constitutive model. The method comprises the following steps: acquiring rock brittleness and plasticity characteristic basic data, performing a triaxial compression test by adopting a high-temperature triaxial compressor, and establishing a constitutive model capable of reflecting deep high-temperature rock damage; according to the mechanical characteristics of the deteriorated rock due to temperature rise, the provided model is verified to accurately simulate stress-strain curves of a sample in each stage of a single axis and a conventional three axis under different temperatures and confining pressures, the rationality of indexes is verified, and the deep high-temperature rock statistical damage constitutive model is obtained. The method solves the problem that in the prior art, a statistical damage constitutive model capable of accurately reflecting stress-strain characteristics of the deep high-temperature rock at each stage of a single axis and a conventional three axis under different temperatures and confining pressures is lacked.

The invention discloses surrounding rock seepage experiment equipment based on triaxial compression and a detection method of the surrounding rock seepage experiment equipment. The surrounding rock seepage experiment equipment comprises a base, an arch-shaped rack fixed to the base, a triaxial pressure assembly, an axial loading assembly, a seepage assembly and a data acquisition assembly, wherein the triaxial pressure assembly, the axial loading assembly, the seepage assembly and the data acquisition assembly are installed on the base; the triaxial pressure assembly comprises a confining pressure self-adaptive homogenizing device, and the confining pressure self-adaptive homogenizing device utilizes a lifting driving assembly to regulate and control the position of an outer cylinder in real time and automatically compensate the surface pressure gradient of a rock sample, so that uniform transfer of confining pressure is ensured, and localized deformation inducements are inhibited fundamentally; for dynamic deformation position data disjunction caused by monitoring capability deficiency, the multi-dimensional permeability monitoring and collecting assembly is driven by the driving assembly to move around a rock sample, a localized deformation area is locked in real time, seepage state parameters (such as permeability and flow velocity) of the position are synchronously captured, and it is ensured that data strictly correspond to the deformation process.

The invention discloses a method for calibrating finite-discrete element input parameters of a water-containing rock, which comprises the following steps of: respectively carrying out a uniaxial tensile test, a uniaxial compression test and a triaxial compression test on a dry rock sample and rock samples with different water contents; obtaining an evolution equation of the tensile strength along with the moisture content, an evolution equation of the elastic modulus and the uniaxial compressive strength along with the moisture content, and an evolution equation of the cohesive force and the internal friction angle along with the moisture content; carrying out a lateral constraint water absorption swelling test on the dry rock to obtain a vertical expansion evolution curve; on the basis of the obtained results, the fracture energy, the humidity expansion coefficient and the humidity diffusion coefficient in the finite-discrete element method are calibrated; on the basis of the calibration parameters, finite-discrete element uniaxial and triaxial compression numerical simulation of the rock samples with different water contents is carried out, and simulation results are obtained; and when the error between the test result and the simulation result is within a preset threshold value, obtaining a final parameter calibration result. The invention provides a simple, accurate and efficient parameter calibration means for water-rock interaction mechanism research.

The embodiment of the invention relates to the technical field of oil exploration and development, in particular to a shale reservoir compressibility calculation method, device and equipment, and the method comprises the steps: obtaining a rock sample of a shale reservoir on a construction site; calculating the bedding development index of the rock sample; the bedding development index represents the bedding structure development degree of the rock sample; performing a triaxial compression experiment on the rock sample under the simulated shale reservoir environment to obtain a brittleness index of the rock sample; the brittleness index represents the strain degree of brittle fracture of the rock sample; scanning the rock sample after the triaxial compression experiment to obtain a fractal dimension index of the rock sample; the fractal dimension index represents the space structure complexity of the three-dimensional crack in the rock sample; and calculating the compressibility of the shale reservoir according to the bedding development index, the brittleness index and the fractal dimension index. According to the embodiment of the invention, the compressibility of the shale reservoir can be accurately and quickly evaluated on the construction site by integrating the bedding structure development degree, the fracture strain degree and the space structure complexity of the rock sample.

The invention belongs to the field of rock mechanics, and particularly discloses a shale multi-scale mechanical property characterization method which comprises the following steps: acquiring mechanical parameters of shale under a macroscale through a triaxial compression experiment; obtaining mechanical parameters of the shale in a mesoscale through a micron indentation experiment; generating a shale surface modulus distribution diagram through a modulus imaging experiment, and combining with an SEM-EDS experiment to determine the composition and elastic modulus of microscopic minerals of the shale; a Mori-Tanaka method is used for carrying out scale upgrading on the micromechanical properties of the shale, the equivalent mechanical parameters of the shale under the macroscopic scale are obtained by integrating the volume fractions, the elastic parameters and the porosity of all phases of microminerals in the shale, and the micromechanical properties and macroscopic response of the microminerals are effectively bridged. According to the method, the anisotropy of the shale in the dimension is disclosed from multiple scales, and the mechanical behaviors and the internal relation of the shale in the macroscopic scale and the microscopic scale are comprehensively disclosed.

The invention provides a method for predicting rock permeability in an elastic-viscoelastic-viscoplastic deformation stage, and belongs to the technical field of rock permeability prediction. In order to effectively predict permeability evolution trends of rocks in different deformation stages and overcome the defects in the prior art, the invention provides a method for predicting permeability of rocks in an elastic-viscoelastic-viscoplastic deformation stage. Obtaining triaxial compressive strength data of the rock under different confining pressure level conditions; setting a creep stress level, and performing a rock sample creep-seepage experiment to obtain axial deformation data of the rock sample and gas pressure data of a gas inlet end and a gas outlet end of the sample; the axial load of the rock sample is unloaded to a hydrostatic pressure state, the confining pressure is kept unchanged, and a seepage experiment in a pressure relief deformation recovery stage is carried out; the method is applied to calculation and prediction of the rock permeability.

The invention discloses a carbonate rock pore retention mechanism simulation method under an ultra-deep heat-fluid-solid coupling effect, and relates to the technical field of rock physics. The method comprises the following steps: preparing a carbonate rock sample, obtaining a CT scanning slice image of the carbonate rock sample, extracting three-dimensional pore information, preparing a plunger sample in a laboratory, carrying out a quasi-triaxial experiment, calibrating mesoscopic parameters by using a laboratory test result, constructing a carbonate rock model, and arranging a measuring ball in the carbonate rock model, the method comprises the following steps: dynamically monitoring the change of porosity and pore pressure, determining a strength reduction function of carbonate rock through a laboratory experiment, applying a true triaxial compression servo environment in which a temperature field and a stress field cooperatively change to a carbonate rock model, and performing true triaxial experiment numerical simulation by using the carbonate rock model. The internal pore condition of the carbonate rock in each evolution stage is obtained, the pore retention mechanism of the carbonate rock under the ultra-deep heat-fluid-solid coupling effect is determined, and technical support is provided for research of carbonate rock reservoirs.

The invention belongs to the technical field of testing and sampling, and particularly discloses a semi-closed tube type static and dynamic triaxial undisturbed sample cutting ring soil sampler. Two ends of an upper joint of the soil sampler are respectively provided with interfaces connected with a drill rod and fixed with a waste soil pipe, and the bottom end of a pipe boot is provided with a cutting edge I; an outer soil sampling pipe of the soil sampling pipe is of a tubular structure formed by buckling two semi-closed pipes, external thread sections are arranged at the two ends of the outer soil sampling pipe respectively, the two ends of the outer soil sampling pipe are in threaded connection with a waste soil pipe and a pipe shoe through the external thread sections, a cutting ring support is of a double-pipe structure formed by buckling two omega-shaped semi-closed pipes, the cross section of the cutting ring support is in a transverse 8 shape, and the cutting ring support can be embedded into the outer soil sampling pipe and is provided with a fixing groove. The cutting ring is of a tubular structure formed by buckling two semi-closed tubes and can be embedded into the fixing groove. The cutting ring support of a semi-closed double-pipe structure is arranged in the soil sampling pipe, and two cutting rings can be fixed through the fixing grooves in the cutting ring support respectively, so that four tailing undisturbed samples can be sampled at a time to meet the requirements of a group of samples for a triaxial compression test, and the device has the characteristics of simple structure, easiness in disassembly and assembly and small disturbance.

A continuous logging method and device is provide, where the method includes obtaining drilling fragment samples and full-diameter core samples, and screening out target rock cuttings from the drilling fragment samples; performing a micro-indentation experiment on the target rock cuttings to obtain a static parameter thereof; performing a triaxial compression experiment on the full-diameter core samples to obtain a dynamic parameter and a static parameter thereof; determining a first correspondence between the static parameter of the target rock cuttings and the dynamic parameter of the full-diameter core samples; determining a second correspondence between logging data and the static parameter of the target rock cuttings based on the first correspondence; and drawing a formation mechanical property profile based on the second correspondence. The method solves the problem of conventional methods which cannot draw a continuous and complete profile of the mechanical property of the whole well section.

An infrared and acoustic emission monitoring rock true triaxial rapid unloading confining pressure test system and method. Mainly include: rigid pressure loading system, air pressure control system, gas confining pressure chamber, infrared observation system. The vertical loading system provides Z direction load; the lateral loading system provides Y direction load; the external gas source provides gas pressure, enters the gas pressure chamber through the floor gas pipeline, provides X direction load; the gas pressure chamber X direction is provided with front and rear infrared observation windows, both are CaF2 glass materials, can erect infrared thermal imager to realize infrared observation; the loading plate can be built-in acoustic emission probe through the detachable structure. The present application uses the pressure head and the pressure plate to provide the pressure in Y direction and Z direction through special design, uses the gas to supply the pressure in X direction, can realize the X direction rapid unloading, and solves the problem that the infrared visualization is difficult to realize in the true triaxial compression test process. Through the detachable design of the loading plate, the acoustic emission probe can be built-in.

The invention relates to a set of mold for preparing a specific-density to-be-tested sample in a triaxial compression test, and belongs to the field of geotechnical engineering sample devices.The mold comprises a pressing and clamping assembly, a forming assembly is arranged in the pressing and clamping assembly, and a pressure applying assembly is slidably connected to the pressing and clamping assembly; the bottom end of the pressure applying assembly extends into the forming assembly to apply pressure to a sample located in the forming assembly, a functional ring is arranged at the end of the pressing and clamping assembly, and the functional ring abuts against the end of the pressing and clamping assembly. According to the invention, the operation process is simplified, the efficiency and safety of taking out the sample are improved, and the preparation work of the sample can be completed more efficiently and accurately, so that the quality and efficiency of a triaxial compression test are improved.

The invention discloses a chamber excavation surrounding rock failure area simulation method and related equipment, and relates to the field of geotechnical engineering stability evaluation.The method comprises the steps that an underground chamber excavation process is simulated through an underground chamber initial model without setting support measures, a plastic zone range is obtained, and principal stress information of a corresponding unit of a failure area is extracted; calculating the damage degree of the surrounding rock based on the surrounding rock stress state; performing zoning operation on the damage area according to the surrounding rock damage degree to obtain refined zoning information; on the basis of a triaxial compression test, rock mechanical parameters related to the residual strength of the surrounding rock under different damage degrees are obtained; assigning values to different partitions with different damage degrees according to the rock mechanical parameters related to the residual strength; and excavation numerical simulation is conducted again to obtain a new plastic zone range and main stress distribution, and final partition assignment and refined simulation are completed. According to the method, the authenticity, engineering adaptability and reliability of numerical simulation are improved, and the method has clear technical progress and engineering practical value.

The embodiment of the present application provides a kind of unconventional oil and gas reservoir brittleness evaluation method, device, equipment, medium and product, it is related to unconventional oil and gas reservoir exploration and development technical field.Aiming at the problem that the brittleness evaluation of current unconventional oil and gas reservoir is not well matched with reservoir reconstruction effect, a brittleness evaluation method according to reservoir rock failure energy and deformation behavior is proposed to realize the quick and accurate evaluation of reservoir rock brittleness, and provide theoretical guidance for the selection of fracturing target reservoir and fracturing scheme design.The present application uses the basic principle that the greater the rock brittleness, the smaller the energy consumed by the rock under uniaxial / triaxial compression and the smaller the rock deformation, combines the uniaxial / triaxial compression failure energy of rock with the deformation of rock at the time of failure, obtains the compression failure energy and deformation parameters of rock using the stress-strain curve of rock, and evaluates the brittleness of reservoir rock by the deformation size under unit energy when rock fails.

This invention discloses a surrounding rock seepage experimental device and its detection method based on triaxial compression, comprising: a base, an arched frame fixed on the base, and a triaxial pressure component, an axial loading component, a seepage component, and a data acquisition component mounted on the base; the triaxial pressure component includes a confining pressure adaptive homogenization device. This invention utilizes a lifting drive component to adjust the position of the outer cylinder in real time through the confining pressure adaptive homogenization device, automatically compensating for the pressure gradient on the rock sample surface, ensuring uniform transmission of confining pressure, and fundamentally suppressing localized deformation causes; addressing the disconnect in dynamic deformation location data caused by insufficient monitoring capabilities, the multidimensional permeability monitoring and acquisition component moves around the rock sample under the drive of the drive component, locking the localized deformation area in real time, and simultaneously capturing the seepage state parameters (such as permeability and flow velocity) at that location, ensuring strict correspondence between the data and the deformation process.

The invention discloses a method for constructing a biaxial compression strength prediction model of a double-hole model sample, which comprises the following steps of: correcting a Mohr-Coulomb strength criterion by combining intermediate principal stress to obtain a Mohr-Coulomb strength formula corresponding to the triaxial compression strength of a complete rock; introducing a hole reduction coefficient, and obtaining a reduction model corresponding to the hole influence; a Mohr-Coulomb strength formula corresponding to the triaxial compression strength of the complete rock is reduced, and a triaxial compression strength prediction model of the double-hole model sample is obtained; and obtaining a biaxial compression strength prediction model of the double-hole model sample. By introducing the hole reduction coefficient, the coupling influence of coexistence of the two holes and geometric configuration of the two holes on the macroscopic strength of the rock mass is clearly quantified, the technical defect that an existing rock mass strength prediction model cannot accurately reflect the strength weakening effect caused by interaction of the two holes is overcome, and compared with a complex full-three-dimensional numerical simulation method, the method has the advantages that the method is easy to implement. The model calculation process is simpler, more convenient and more efficient.

The invention relates to a triaxial rock brittleness evaluation method based on a cohesive polymerization degradation-friction strengthening model. The triaxial rock brittleness evaluation method comprises the following steps: obtaining a load-time curve and a uniaxial stress-strain curve of a Brazilian splitting experiment and a stress-strain curve of a triaxial compression experiment; determining a uniaxial brittleness index based on a Mohr-Coulomb shear strength curve and a CWFS model according to a load-time curve and a uniaxial stress-strain curve; determining a confining pressure influence brittleness coefficient according to a triaxial stress-strain curve under different confining pressures based on the Moire circle, the cohesive force and the friction angle change trend under the triaxial stress state; and determining a triaxial brittleness index Btri by using the uniaxial brittleness index Bu and the confining pressure influence brittleness coefficient Bp. The core parameters adopted by the brittleness index are cohesive force and internal friction angle and can be directly obtained through petroleum engineering conventional logging data inversion, the field application threshold is remarkably reduced, and the limitation that the traditional brittleness index depends on special experimental data is broken through.

The utility model discloses a triaxial compression working condition loading clamp for a thermal shock test, which comprises a lower end plate and an upper end plate, the lower end plate and the upper end plate are correspondingly provided with a plurality of mounting through holes, the plurality of mounting through holes are uniformly distributed, a bolt piece is arranged in each mounting through hole, the lower end plate is connected with the upper end plate through the bolt pieces, and the lower end plate is connected with the upper end plate through the bolt pieces. A plurality of test piece mounting grooves are formed between the adjacent mounting through holes; a large strip-shaped groove and a small strip-shaped groove are formed in the middle of the lower end plate, and the middle of the large strip-shaped groove and the middle of the small strip-shaped groove are communicated in a crossed mode. The lower end plate and the upper end plate of the triaxial compression working condition loading clamp are provided with corresponding test piece mounting grooves, so that loading of a plurality of test pieces in the axial direction can be realized; the lower end plate and the upper end plate are provided with corresponding large strip-shaped grooves and small strip-shaped grooves, so that external pressure or internal pressure loading of a plurality of test pieces can be realized; therefore, the test piece can also realize a loading test under a triaxial compression working condition at a thermal shock temperature.

The invention discloses a rock dynamic and static tension and compression multi-field coupling test method, and relates to the technical field of rock dynamic load, static load, tension and compression, shearing, rheology, temperature, seepage, chemistry, ultrasonic wave, acoustic emission, resistivity and other multi-field coupling tests. The sample is of a dumbbell-shaped structure with upper and lower end diameters larger than the middle diameter; the method comprises a triaxial axial tensile test, a triaxial compression test, a triaxial dynamic impact test, a dynamic and static triaxial multi-field coupling test at different temperatures and a true triaxial shear seepage coupling test. In the triaxial tensile test process, the end part of the test sample does not need to be glued, the test sample adopts a dumbbell-shaped test sample shape design, the axial tensile force is provided by using a confining pressure loading system and adopting confining pressure, and the axial tensile test of the rock under different confining pressure conditions can be realized.

This application discloses a rapid method for determining the macroscopic strength parameters of layered rock masses. For layered rock masses without discontinuous joints or fractures, the method includes the following steps: S1. Conducting conventional uniaxial triaxial compression tests on matrix rock blocks to obtain the stress-strain curves of the matrix rock blocks, and fitting the peak strength and residual strength of the matrix rock blocks under different confining pressures to obtain the strength parameters of the matrix rock blocks; S2. Conducting shear tests on bedding samples to obtain the stress-strain curves of the bedding surfaces, and fitting the peak strength and residual strength of the bedding surfaces under different normal stresses to obtain the strength parameters of the bedding surfaces; S3. Taking the average of the peak strength of the matrix rock blocks and the peak strength of the bedding surfaces, as well as the average of the residual strength of the matrix rock blocks and the residual strength of the bedding surfaces, to obtain the macroscopic equivalent strength parameters of the layered rock mass without discontinuous joints or fractures.

The invention discloses a gas-solid coupling creep disturbance effect test device, and belongs to the technical field of rock rheological disturbance tests. Comprising an axial pressurization device, a disturbance impact device, a three-axle box, an axial pressure transmission column, a limiting device, a confining pressure control device and a gas seepage device. The device is high in overall stability and air tightness, can be used for conventional rock uniaxial and triaxial compression creep disturbance tests, and can also be used for gas-solid coupling creep disturbance tests for gas-containing coal rocks. The device meets the requirements of a rock rheological disturbance effect test, and provides an important experimental basis for researching rock mass fracture and damage evolution characteristics under the rheological disturbance condition. According to the pneumatic impact device, the impact weight does not need to be manually lifted to apply impact, and is changed into pneumatic impact, so that the safety and the convenience are remarkably improved. The pneumatic impact load flexibility and controllability are higher, so that researchers can design various different experiment schemes including disturbance of frequency conversion, impact amplitude and duration.

The invention discloses a rock true triaxial compression test device and method. The device comprises an annular force bearing frame; the heating box comprises a first box wall, a second box wall and a door body assembly which define a box body structure, the second box wall is provided with an operation opening, the door body assembly opens or closes the operation opening, the first box wall is provided with a first pressing head, and the second box wall or the door body assembly is provided with a second pressing head; the actuator assembly comprises a first actuator corresponding to the first pressure head and a second actuator corresponding to the second pressure head, and the first actuator is connected with the annular force bearing frame and the corresponding first pressure head; the enclasping telescopic assembly is connected with the annular force bearing frame and the second actuator and is configured to drive the second actuator to be close to or away from the second box wall; and the clamping device is configured to clamp or loosen the rock test piece and is configured to be in contact with the first pressure head and the second pressure head. Therefore, the rock test piece can be quickly loaded and unloaded, and the experimental efficiency and the authenticity and accuracy of experimental data are improved.

The invention relates to a triaxial compression numerical simulation method for heterogeneous stratified rock. The method comprises the following steps: S1, establishing a rock numerical model; s2, establishing different bedding inclination angle models; s3, generating contact among the particles; s4, generating contacts of different groups; step S5, generating a random number parameter obeying Weber distribution; s6, respectively generating parameter models obeying Weber distribution for rock matrix-rock matrix contact, bedding-bedding contact, rock-bedding contact, rock-wall body contact and bedding-wall body contact in the step S4 by using the micro-mechanical parameters obeying Weber distribution generated in the step S5; and S7, carrying out simulated damage on the parameter model established in the step S6. The method has both flexibility and expansibility, and finer simulation can be realized by adjusting the shape and distribution parameters of the particles when different types of rocks or different loading conditions are processed.

The invention discloses a multifunctional pressure chamber and a test method, and relates to the field of geotechnical engineering test equipment.The multifunctional pressure chamber comprises a pressure chamber shell, a closed cavity used for containing a sample is formed in the pressure chamber shell, and an axial loading piston penetrates through the center of the top of the pressure chamber shell and is used for applying axial stress to the sample; a confining pressure liquid inlet and outlet is formed in the lower part of the pressure chamber shell, hydraulic oil is injected into the closed chamber through the confining pressure liquid inlet and outlet, and uniform radial confining pressure is applied to the sample; a flexible capsule is embedded in the sample clamping frame, the flexible capsule is attached to the sample through an end sliding block, a flexible capsule hydraulic medium inlet and outlet connected with the flexible capsule is further formed in the pressure chamber shell, a pressure medium is injected into the flexible capsule through the flexible capsule hydraulic medium inlet and outlet, and therefore stress is independently applied to the sample in the second direction. The three test functions of uniaxial compression, conventional triaxial compression and true triaxial compression can be realized on the same device, the integration level is high, the conversion is convenient and fast, and the cost is low.

The present invention provides a test method for simulating the influence of soft and hard interlayered bedrock on the deformation and damage of pile foundation. The method comprises: preparing a combination sample A simulating soft and hard interlayered bedrock and a comparative combination sample B simulating hard layered bedrock by a mold, and performing a loading test on the model piles in the combination sample A and the comparative combination sample B, wherein the loading method adopts graded loading; drawing the axial stress-axial displacement relationship curve of the model piles in the two combination samples according to the test results, and drawing the two groups of test curves in the same coordinate system to obtain a comparative curve diagram of the two groups of tests, and providing a theoretical basis for the optimization of pile length in soft and hard interlayered bedrock in the later stage by observing the relationship between the two groups of curves. The present invention utilizes an existing triaxial compression testing machine and adopts a combination sample to simulate the influence of soft and hard interlayered bedrock on pile foundation, and provides a reference basis for optimizing the length of pile foundation through the test comparison results.

The invention discloses a core concrete triaxial compressive stress detection device and detection method, and the key point of the technical scheme is that the core concrete triaxial compressive stress detection device comprises a triaxial compressive stress detection table; a steel tube concrete placing table is formed on the triaxial compressive stress detection table; a triaxial compressive stress detection mechanism is assembled on the concrete filled steel tube placement table and comprises a base table arranged on a triaxial compressive stress detection table. Through reasonable arrangement of the triaxial compressive stress detection table, the concrete filled steel tube placement table and the triaxial compressive stress detection mechanism on the concrete filled steel tube placement table, stable placement of a test piece and close fit of the detection mechanism are realized, and the accuracy and reliability of the whole detection process are ensured; a layered supporting structure of the base table, the supporting frame and the bearing beam is combined with the two linear guide rails arranged in parallel in the transverse direction of the bearing beam and the guide rail platform sliding on the side faces of the linear guide rails, so that the detection device has good transverse moving and positioning capacity, the detection position can be conveniently and accurately adjusted, and the flexibility and the detection efficiency of the device are improved.

A method for judging the activation tendency of hydraulic fracturing induced fault considering rock damage: 1) basic parameters adopt triaxial compression experiment, respectively determine the cohesion c, internal friction angle phi of hydraulic fracturing formation, pore water pressure p0, logging and seismic inversion data determine the first, second and third principal stress of fault sigma1, sigma2, sigma3, the length L of the hydraulic fracture closest to the fault and the fault dip angle beta and strike; 2) based on the Mohr-Coulomb law, the state function M(D) of the activation tendency of the fault is established by the damage variable D; 3) the discrimination criterion of the activation tendency of the fault is established, and the tendency and risk of the activation of the fault are evaluated according to the discriminant formula. Through the above method, the activation of the fault can be more accurately predicted, the safety of hydraulic fracturing operation is effectively improved, and the possible earthquake accident can be avoided.