25 results about "Cyclic shear" patented technology

The invention discloses a large-scale visualized direct shear test device and method for geosynthetics. The device comprises a main frame, an upper shear box, a lower shear box, a normal cyclic loading system, a horizontal cyclic shear loading system, a data acquisition system and a visualized monitoring system. The direct shear test device is characterized in that the direct shear test device can perform normal and horizontal cyclic loading at the same time, and normal stress with different frequencies and amplitudes can be applied according to needs to simulate a test of the characteristics of the reinforcement-soil interface under the cyclic loading effect; one side wall of the upper shear box and one side wall of the lower shear box are transparent observation windows, and a high-speed camera and a digital image analysis method are combined, so that the shear band evolution process can be visually observed and quantitatively analyzed; the shear box is large in size, and the size effect is effectively overcome. According to the invention, the interface characteristics under the cyclic load effect in the road engineering can be reflected more truly and comprehensively, the size and the function of the shear box are comprehensive, and the interface mechanical characteristics and the interaction mechanism under various working conditions can be simulated.

The invention relates to a saturated sand dynamic constitutive model construction method considering pore pressure fluctuation growth, which comprises the following steps: determining total pore water pressure including residual pore pressure component and transient pore pressure component, and constructing a normalized stress ratio skeleton curve independent of a pore pressure state; correcting the total pore water pressure to obtain corrected pore water pressure, and updating the average effective stress at the current moment by using the corrected pore water pressure; coupling the normalized stress ratio skeleton curve and the updated average effective stress to obtain a maximum shear stress value; the maximum shear stress value is used as a target state point, a dynamic virtual hysteretic curve is constructed, the stress-strain behavior of saturated sandy soil is described, accumulated damage and alternate shear shrinkage-shear expansion effects of a soil body in the cyclic loading process can be effectively considered, a pore pressure development curve and cyclic shear stress-strain response which better conform to the test rule are captured, and the test accuracy is improved. And a valuable tool is provided for evaluating the response and liquefaction strength of the saturated sand under the undrained cyclic loading condition.

The invention relates to the technical field of site saturated sandy soil liquefaction discrimination, in particular to a subway train shield tunnel underlying sandy soil layer liquefaction potential rapid assessment method based on vibration inversion, and solves the problem that the sandy soil liquefaction condition caused by subway train vibration loads cannot be assessed. The sandy soil liquefaction possibility of the target site under the action of subway train operation is rapidly and reliably evaluated, so that the requirement for early warning of liquefaction risks caused by subway vibration in the railway underpass shield tunnel engineering is met; according to the shear wave velocity Vs of the soil layer, the cycle resistance ratio CRR of the soil layer is determined; through vibration load inversion, the equivalent cyclic shear stress ratio (CSR) borne by the tunnel underlying soil layer is determined; when the equivalent cyclic shear stress ratio CSR is greater than the contrast soil layer cyclic resistance ratio CRR, the tunnel underlying layer has a liquefaction risk; otherwise, the tunnel underlying layer has no liquefaction risk.

The utility model belongs to the technical field of hydraulic oil product performance evaluation equipment, and particularly relates to a hydraulic oil shearing stability evaluation device which comprises a hydraulic oil tank, a shearing module and a sampling module. And an oil outlet path is connected between the oil outlet end of the shearing module and the hydraulic oil tank. The testing principle of the shearing stability is that the hydraulic oil sample is circularly sheared within the testing time, and the viscosity of the hydraulic oil sample is measured after the testing time is up. According to the hydraulic oil shear stability evaluation device, the hydraulic oil tank, the oil inlet oil way, the shearing unit and the oil outlet oil way form the hydraulic oil way, in other words, the evaluation process of the shear stability is directly conducted in the hydraulic oil way, running-in of components for testing is not needed, and it can be seen that the test efficiency is greatly improved. And the test period of the shear stability is obviously shortened so as to realize rapid judgment of the shear stability.

The embodiment of the application provides a joint surface peak shear strength prediction method, device, equipment, medium and program product, the method comprises the following steps: scanning the original rock joint surface to obtain the original rock joint point cloud data; acquire a description function, and describe the distribution of microconvex bodies in the original rock joint surface by combining the joint point cloud data with the description function; determine the distribution function density and any normal stress; determine the average value of the actual contact joint microconvex body inclination according to the initial peak dilatancy angle of the initial state when no cyclic shear occurs, and determine the peak dilatancy angle when a plurality of cyclic shears occur; according to the number of cyclic shears, a peak shear strength prediction model of the joint surface is determined; the model is simple to calculate, can realize high-precision prediction only by a small number of parameters, and is suitable for engineering application.

The invention discloses an offshore wind power pile foundation surrounding soil damage state judgment method, which comprises the following steps: S1, carrying out a soil indoor cyclic load test to obtain a cyclic shear strain cumulative diagram; S2, obtaining complex wave force load data, and converting the data into a group of cyclic shear stress ratio data ranked from small to large; s2, finding a minimum cyclic shear stress ratio and a corresponding cyclic vibration frequency, and obtaining an equivalent cyclic vibration frequency corresponding to a next cyclic shear stress ratio based on the cyclic shear strain cumulative diagram obtained in S1; repeating the same operation until a final equivalent cycle vibration frequency corresponding to the maximum cycle shear stress ratio is obtained; s3, obtaining corresponding damage vibration times under different working conditions, and obtaining a damage vibration time contour map; s4, according to the average shear stress, finding a corresponding damage vibration frequency in the damage vibration frequency contour map obtained in S3; and comparing the final equivalent cycle vibration frequency with the damage vibration frequency, and judging whether the soil body is damaged or not. According to the method, the cost is reduced, the universality is high, and the precision can be ensured.

The invention relates to the technical field of stainless steel powder injection molding, in particular to stainless steel powder injection molding equipment and a preparation method.The stainless steel powder injection molding equipment comprises a mounting support and a filtering tank rotationally mounted on the mounting support, a guiding pipeline is fixedly mounted at the upper end of the filtering tank, and a heating connecting tank is fixedly mounted at the upper end of the guiding pipeline; a detachable upper cover is arranged at the upper end of the heating connecting tank, a discharging pipe is fixedly installed at the lower end of the filtering tank, and movable rotating columns are arranged in the filtering tank, the guiding pipeline, the heating connecting tank and the discharging pipe. Materials are turned over upwards through the inclined paddle structure to form a flow field direction opposite to that of the stirring rod, and the stirring rod and the paddle move oppositely to form a strong convection area at the junction of the heating connecting tank and the guide pipeline, so that the materials are forced to undergo multiple times of cyclic shearing and convection diffusion, and the problem of dead angles existing in traditional single stirring is solved; it is further ensured that the binder completely wraps the powder particles, and high-uniformity feeding is provided for subsequent injection molding.

The invention provides an ocean clay-geogrid interface cyclic shear stress prediction model construction method, and relates to the technical field of ocean engineering. The method comprises the following steps: preparing and assembling a marine clay-geogrid interface shear test sample; after the sample is assembled, performing a multi-working-condition interface cyclic shear test to obtain effective original test data; based on the effective original test data, constructing an interface cyclic shear test database; constructing and training a deep learning prediction model based on the interface cyclic shear test database; verifying the precision of the prediction model, screening out an optimal prediction model, and building a marine clay-geogrid interface cyclic shear stress prediction formula based on the optimal prediction model. According to the method, reliable test data under multiple working conditions are obtained, the CNN-BiLSTM model is constructed to accurately describe the shear stress evolution law, the engineering available prediction formula is established, and reliable support is provided for ocean engineering reinforced structure design and safety evaluation.

This utility model discloses a shearing mechanism for a vacuum mixer, comprising a mixing and shearing cylinder, a stator, and a rotor. The stator is sleeved outside the rotor and connected to the mixing and shearing cylinder via a lifting mechanism. The rotor is rotatably mounted inside the mixing and shearing cylinder and is driven by a motor that rotates it. The motor is mounted outside the mixing and shearing cylinder. A circulation line is provided at the lower end of the side wall of the mixing and shearing cylinder. The shearing mechanism for a vacuum mixer provided by this utility model utilizes a lifting mechanism to raise and lower the stator, thereby adjusting the shearing gap between the stator and rotor. This allows the device to meet the needs of different working conditions. Furthermore, the circulation line enables the device to perform cyclic shearing of materials during use, effectively improving the shearing efficiency of the device.

The application relates to a polymer reaction extrusion modification device with a circulating shearing structure. The device comprises an extruder, and the extruder comprises a barrel, characterized in that the barrel comprises a first section, a middle section and a tail section, the middle section is provided with a circulating structure; the circulating structure comprises a circulating pipeline and a driving module, the circulating pipeline is used for leading the polymer from the middle section of the barrel back to the upstream to form a circulating shearing, and the driving module is used for driving the circulating pipeline to rotate along the axis of the barrel, so that the position of a feeding port of the circulating pipeline relative to the barrel changes; according to the application, the circulating pipeline is arranged independently of the barrel of the extruder, controllable physical shearing can be applied to the product after the grafting reaction is completed, and the problem that the reaction and the shearing interfere with each other in the traditional device is avoided.

The application provides a marine clay-geogrid interface cyclic shear stress prediction model construction method, and relates to the technical field of marine engineering. The method comprises the following steps: preparing and assembling a marine clay-geogrid interface shear test sample; after the sample is assembled, a multi-working-condition interface cyclic shear test is carried out to obtain effective original test data; based on the effective original test data, an interface cyclic shear test database is constructed; based on the interface cyclic shear test database, a deep learning prediction model is constructed and trained; the accuracy of the prediction model is verified, the optimal prediction model is screened out, and a marine clay-geogrid interface cyclic shear stress prediction formula is built based on the optimal prediction model. The application can obtain reliable test data under multiple working conditions, accurately depict the shear stress evolution law by constructing a CNN-BiLSTM model, build an engineering usable prediction formula, and provide reliable support for the design and safety evaluation of marine engineering reinforced structures.

This invention provides a method for correcting the vertical bearing capacity of pile foundations in liquefiable silty soil considering the vibration time effect, relating to the field of geotechnical engineering. This method includes S1: based on vibration time history data from the engineering site, baseline correction, bandpass filtering, and normalization are performed on the original vibration acceleration time history to obtain a standardized vibration acceleration time sequence; S2: based on the standardized vibration acceleration time sequence, a one-dimensional equivalent shear beam model is used for seismic response analysis to calculate the cyclic shear stress time history distribution of soil layers at different depths, obtaining the cyclic shear stress time history distribution field of the soil layers. By performing baseline correction, frequency band filtering, and amplitude unification processing on the vibration acceleration time history, the input data possesses stable spectral characteristics and a consistent scale foundation, and combined with a shear propagation model, a continuous distribution of stress response at different depths over time is obtained.

The invention discloses a multi-field coupling control unsaturated soil direct shear test system and method, and belongs to the technical field of geotechnical engineering. The system comprises a high-pressure sealing pressure-bearing loading host, a shear box assembly integrating a pottery clay plate and a temperature control flow channel, a dual-channel environment control system and a servo loading and acquisition control system. Accurate control of matrix suction is realized by combining a high-pressure closed cavity with an axial translation technology, wide-temperature-range wrapped temperature control is realized through a shear box side wall integrated flow channel, active control of three complex normal boundary conditions of constant load, constant rigidity and constant volume is realized by adopting a normal servo driving module with a built-in sensor, and meanwhile, the normal servo driving module is used for driving the shear box side wall integrated flow channel to control the temperature of the shear box side wall integrated flow channel. Monotonic shearing and cyclic shearing of unsaturated soil are achieved through the horizontal shearing servo driving module. The problem that traditional equipment cannot accurately test static and dynamic characteristics of unsaturated soil in a multi-field coupling environment is solved, and a high-simulation test platform is provided for soil behavior research under complex working conditions.

This invention discloses a wet-dry cycle-shear coupled secondary sample preparation device and testing method. The device includes a shear system, a wet-dry cycle system, and a support structure. The shear system is used to apply horizontal shear loads and normal loads, the wet-dry cycle system is used to synchronously control the wetting and drying process of the original ring sample, and the support structure is used to fix the overall device. The testing method includes secondary coupled sample preparation and direct shear test. The secondary coupled sample preparation forms a preset shear surface through the coupling effect of wet-dry cycle and shear stress. The direct shear test measures soil strength parameters under multiple working conditions and analyzes the strength evolution law. This invention solves the problem that existing technologies cannot synchronously control the wet and dry state of secondary processed samples during shearing, realizes real-time coupling of wet-dry cycle and shear load, realistically simulates the actual stress state of expansive soil slopes, overcomes the limitations of in-situ sampling and single wet-dry cycle test, and provides a reliable test platform for long-term stability evaluation of expansive soil slopes.

The invention relates to a testing device for cyclic shear characteristics of a geotechnical material structure interface. The testing device comprises a shear box system, a vertical loading mechanism, a horizontal loading mechanism and a horizontal supporting mechanism. And the shear box system comprises a shear box main body and a soil body chamber in the shear box main body. The horizontal loading mechanism drives the shear box body to move horizontally, the horizontal supporting mechanism penetrates through the side wall of the shear box body and supports the soil body chamber to limit horizontal movement of the soil body chamber, and the stress action lines of the horizontal supporting mechanism and the soil body chamber are collinear. The shear box body is flush with the top of the soil body chamber, and the bottom is filled with a structural plane material sample and injected with liquid. The soil body chamber is filled with a rock-soil sample, the bottom surface of the rock-soil sample is in contact with the top surface of the structural surface sample, and the top surface is lower than the liquid level. The vertical loading mechanism is used for applying a load to the rock-soil sample. Compared with the prior art, the problem that the test accuracy is reduced due to the fact that the contact surfaces of the two samples incline is effectively solved.

The invention discloses a device and a method for simulating pile-soil interface cyclic shear characteristics in a hydrate replacement exploitation process, and particularly relates to the field of natural gas hydrate exploitation, the device comprises a supporting structure, a power mechanism, a high-pressure reaction kettle system, a control system, a data acquisition system and a data storage system, the high-pressure reaction kettle system comprises a high-pressure reaction kettle, an upper end cover is arranged at the top of the high-pressure reaction kettle, a lower end cover is arranged at the bottom of the high-pressure reaction kettle, high-strength screws are arranged in the upper end cover and the lower end cover, the high-strength screws are in threaded connection with the supporting structure, and sealing rings are connected to the outer sides of the bottoms of the upper end cover and the lower end cover in a sleeving manner. The device can accurately simulate a deep sea high-pressure environment, realizes a CO2 generation and replacement process of methane hydrate, can perform high-precision monotonous or cyclic shear test on a pile-soil interface in and after the process, effectively eliminates a rigid boundary effect, and obtains real and reliable interface mechanical parameters.

Disclosed are an underground engineering rock mass shear simulation test device, a test method and a test machine. The test method includes: setting different test conditions by a controller to perform cyclic shear test at high temperature, fracture shear seepage test, granite uniaxial compression test at high temperature and granite fracture shear test under constant normal stiffness boundary conditions at room temperature. The electric heating wire assembly, the fan assembly and the environmental box are combined to flexibly and uniformly heat the samples placed in the upper shear box and the lower shear box. In terms of shear-seepage test, this scheme proposes a second sample placing mechanism that realizes sealing through sealing capsule and sealing capsule pressing plate. It realizes stable sealing and facilitates monitoring and debugging of seepage parameters.

The invention discloses a three-dimensional site liquefaction discrimination method based on cyclic stress. The discrimination method comprises the following steps: obtaining site seismic parameters and geological map layer conditions; establishing a three-dimensional site grid model to carry out attribute assignment on different soil types; carrying out a field standard penetration test and an indoor static and dynamic triaxial test to obtain soil property parameters; soil property parameters are tested; two times of overlying effective stress correction are carried out to generate a three-dimensional field actual measurement average standard penetration field; generating an equivalent 7.5-level earthquake soil circulation resistance ratio field of the three-dimensional field; a three-dimensional site soil body circulation resistance ratio field is generated; generating a three-dimensional field earthquake cyclic shear stress ratio field; a three-dimensional site anti-liquefaction safety coefficient field is generated; and determining the liquefaction possibility of the three-dimensional site. According to the method, the defects of a traditional simplification method in real stress path expression and soil nonlinear response simulation are effectively overcome; the precision of three-dimensional CRR calculation is improved; and the liquefaction evaluation of the site can be integrally and intuitively carried out. The liquefaction judgment result conforms to the actual situation, and engineering application is guided to be more reasonable and effective.

The invention provides an underground soil liquefaction monitoring test device based on air pressure and non-Newtonian fluid, a first piston plate and a second piston plate which are distributed at an interval are arranged in a shell, and a displacement sensor is arranged between the first piston plate and the second piston plate; one end of the dowel bar is fixed in the middle of the first piston plate, the other end of the dowel bar penetrates through the second piston plate and then is connected with the porous damping plate, and the porous damping plate is slidably assembled in the shell and forms a non-Newtonian fluid cavity with the second piston plate; an air pressure cavity is arranged to simulate the pore pressure rising process, non-Newtonian fluid is adopted to simulate the shear thinning and weakening behavior, and controllable loading, quantitative measurement and repeated testing of the liquefaction behavior are achieved through an air pressure-piston-non-Newtonian fluid-porous damping plate coupling transmission mechanism. And rheological indexes in the liquefaction process can be monitored in real time under disturbance conditions of vibration, impact, cyclic shearing and the like.

This invention relates to the field of liquefaction assessment technology for saturated sandy soil, specifically to a rapid assessment method for the liquefaction potential of sandy soil layers beneath subway train shield tunnels based on vibration inversion. This method addresses the problem of the inability to assess the liquefaction of sandy soils induced by subway train vibration loads, enabling rapid and reliable assessment of the liquefaction probability of sandy soils at a target site under subway train operation. This meets the early warning requirements for liquefaction risks caused by subway vibration in railway underpass shield tunnel projects. The method is based on soil shear wave velocity... V s Determine the cyclic resistance ratio of the soil layer CRR By inverting vibration loads, the equivalent cyclic shear stress ratio of the underlying soil layer was determined. CSR When the equivalent cyclic shear stress ratio CSR greater than Comparison of soil cyclic resistance ratio CRR hour ， The underlying layer of a tunnel is at risk of liquefaction; conversely, the underlying layer of a tunnel is not at risk of liquefaction.

This invention discloses a pore pressure model and its modeling method related to the loading path of soil granular materials, belonging to the technical field of mechanical properties of soil media in extreme environments. The modeling method includes the following steps: S1: simplifying the complex working conditions; S2: designing unidirectional and multidirectional cyclic shear test schemes; S3: conducting unidirectional and multidirectional cyclic shear tests and obtaining test data; S4: systematically processing the pore pressure, deformation, and dissipation energy characteristics; S5: establishing and fitting a pore pressure fitting model to obtain a pore pressure fitting model with determined fitting parameters, which is the pore pressure model. This invention can more reasonably reflect the pore pressure growth, effective stress decay, and liquefaction development process of soil under complex stress conditions, improve the applicability and predictive ability of the pore pressure model in complex dynamic environments, and provide technical support for geotechnical engineering design and disaster prevention and mitigation in active fault zones and complex dynamic environments.

The invention relates to the technical field of concrete mechanical property testing, and particularly discloses a cyclic shear test device and method for a new and old concrete combined test block. The device comprises a base used for placing and supporting a combined test block. And the shear loading assembly comprises two loading mechanisms. The two loading mechanisms are respectively connected with the new concrete test block and the old concrete test block and are used for respectively and simultaneously applying alternating acting force parallel to the joint surface to the new concrete test block and the old concrete test block. And the normal loading assembly is used for applying normal pressure perpendicular to the combination surface to the combined test block. And the antifriction unit is arranged between the normal loading assembly and the combined test block and is used for reducing friction interference between the normal loading assembly and the combined test block. By means of the arrangement, the device can simulate the complex working condition of a shield tunnel double-layer lining scene, friction interference caused by normal pressure is reduced, and accurate testing of the anti-seismic performance of the joint surface is achieved.

The present invention relates to a large-scale triaxial dynamic geotechnical shear test system and a test method. The large-scale triaxial dynamic geotechnical shear test system comprises a four-column loading frame, a shear box, a z-axis servo cylinder, a x-axis servo cylinder, a y-axis servo cylinder, a specimen transport system, a hydraulic system, a cooling system, a data collection system, a computer control system, and a computer control cabinet; the shear box can be transported into the four-column loading frame by means of the specimen transport system; the computer control system is electrically connected to the computer control cabinet; and the hydraulic system, the cooling system, and the data collection system are all electrically connected to the computer control system. The present invention has the beneficial effect of enabling a triaxial direct shear, triaxial simple shear, or triaxial cyclic shear test on rock and soil masses under conditions of constant normal load, constant normal stiffness, and dynamic normal load, allowing the study of the influence of multi-directional characteristics of seismic motion on dynamic properties of rocks, facilitating revelation of the mechanism of slope dynamic instability.

The invention belongs to the technical field of oil and gas geology, and particularly relates to a true triaxial multi-field coupling experiment device and method for a CO2 sequestration geologic body fault. Comprising a loading frame, a self-balancing shear-seepage multi-field coupling module, a vertical servo stress module and a horizontal servo stress module. The multi-field coupling module is composed of a pressure chamber and a self-balancing piston. The multi-field coupling experiment system comprises a true triaxial multi-field coupling experiment device, a confining pressure loading device, a control and acquisition device, an acoustic emission monitoring device and a constant-speed constant-pressure pump. The experimental method comprises the following steps: 1, equipment debugging; 2, carrying out a conventional shear-seepage experiment, namely carrying out a shear experiment and a shear-seepage experiment at different shear rates; and 3, carrying out a multi-period cyclic shear experiment, and carrying out a normal stress alternating experiment and a tangential stress-displacement alternating experiment. And 4, performing a fault shear-seepage creep experiment, determining the maximum shear stress, designing a graded load, performing a shear creep experiment on the fault under carbon dioxide sequestration, and analyzing creep characteristics.

The application relates to a saturated sand dynamic constitutive model construction method considering pore pressure fluctuation growth, which comprises the following steps: determining total pore water pressure, which comprises a residual pore pressure component and a transient pore pressure component, and constructing a normalized stress ratio skeleton curve independent of the pore pressure state; correcting the total pore water pressure to obtain a corrected pore water pressure, and updating the average effective stress at the current time by using the corrected pore water pressure; coupling the normalized stress ratio skeleton curve and the updated average effective stress to obtain a maximum shear stress value; taking the maximum shear stress value as a target state point to construct a dynamic virtual hysteresis curve, which describes the stress-strain behavior of saturated sand, can effectively consider the cumulative damage and alternating shear shrinkage-dilation effect of the soil in the cyclic loading process, and can capture the pore pressure development curve and the cyclic shear stress-strain response which are more in line with the test law, thereby providing a valuable tool for evaluating the response and liquefaction strength of saturated sand under undrained cyclic loading conditions.