142 results about "Stress path" patented technology

The invention discloses a true triaxial apparatus without pressure cell structure, of which deformation is free from side interference, and the true triaxial apparatus is applicable to the true triaxial test of soil samples comprising coarse-grained soil and fine-grained soil. A rigid plate is used to pressurize in vertical direction, the bottom surface of the rigid plate and the top surface of the base are respectively provided with a roller for preventing side interference; rigid and flexible mixed blocks which are composed of metal plates and hollow rubber pipes in an alternating manner are used to pressurize in the front-rear direction, the true triaxial apparatus can be compressed along with the sample driven by the rollers in the vertical direction but in the horizontal direction; and a flexible water pocket structure is used to pressurize in left-right direction. The deformations of the sample in three directions can be obtained by the conversion calculation of the rotation circle-number of the motor in the corresponding direction, thus the accuracy is higher. The true triaxial apparatus can be used for the test of stress path in three-dimensional stress space, and the side interference can be efficiently avoided when the deformation of the sample is relatively obvious.

The invention discloses a multifunctional true triaxial rock creepmeter, comprising a base, a test piece mounting base arranged on the base, two groups of horizontal direction stress loading systems with the same structure, a vertical direction stress loading system and a creep data measuring system. The multifunctional true triaxial rock creepmeter disclosed by the invention can carry out a single-axis pulling and pressing creep test and also can carry out a true triaxial compression, pulling and pressing combined creep and unloading-creep test which simulates three-dimensional stress state and loading and unloading stress path of a natural geological rock mass and an engineering rock mass and maintain tension stress states in one or two directions unloaded to the rock; and test function is more comprehensive, practicability is stronger, and a pulling and pressing combined creep and stable pressing and pulling stress conversion unloading-creep test is realized; a pull pressure loading system can provide a pressure which is high enough to meet creep test requirements of most rock materials, and a long-term constant load can be provided; and the multifunctional true triaxial rock creepmeter disclosed by the invention has the characteristics of having a simpler structure, hardly consuming energy source in a test process and having low test cost.

The invention relates to a stress-strain information measurement device and method for a thin-walled tube, in particular to a bidirectional stress state stress-strain measurement device and method for a thin-walled tube. The device and method are used for solving the problems that according to an existing device and method, accurate control over a stress path and accurate measurement of stress-strain information can not be achieved in a bidirectional stress state of the thin-walled tube, and the accurate stress-strain information can not be obtained when the thin-walled tube is in the bidirectional stress state. The device comprises a base, a strain gage, a movable beam, a pump station, an oil pressure booster, a force sensor, a pressure sensor, a control system, two upper chucks, two lower chucks, two lead screw pairs and two motors, wherein the two motors are installed on the base in parallel, and one lead screw pair is fixedly installed at the output end of each motor. The measurement method includes the main steps that firstly, the thin-walled tube is selected; secondly, the two ends of the thin-walled tube are fixed and sealed; thirdly, a bidirectional stress-strain experiment is started; fourthly, the stress-strain information is detected; fifthly, the thin-walled tube is broken, and experimental data are saved.

Disclosed is a rock true triaxial pressure chamber. Four self-balance pistons which are arranged crosswise are disposed on a wall of the chamber. Each piston has a pressure cavity and a backpressure cavity, wherein the pressure cavity is attached to the pressure chamber through an external oil-way provided with a one-way valve; and the backpressure cavity is respectively attached to the atmosphere and a hand pump for transposition through a pipeline and the one-way valve. The self-balance pistons are provided with a pressure control system which reliefs pressure of the external oil-way of the piston's pressure cavity through the hand pump. An EDC controller receives feedback signals of a pressure transducer and a force transducer and outputs a control command to a Moog servo valve. According to the command, the servo valve controls the external oil-way for oil supply of an actuator and adjusts the pressure on the pistons. The advantage of original two-hardness one-softness true triaxial pressure chamber is maintained in the invention. On this basis, a self-balance to non-self-balance transition function is added in the true triaxial pressure chamber provided by the invention, thus making up the insufficiency that the original true triaxial pressure chamber can only unload hydrostatic pressure and realizing unloading of complete stress path.

The invention discloses a test method and system for simulating bonding property between undisturbed rock-soil and an anchor under formation pressure. The test system comprises: a measuring device, asample fixing device, a formation pressure simulating device, and a pressure grouting device. Pressure bladders are mounted on the side surface and the top surface of a sample, respectively. A radialdeformation gauge is mounted on the outside of the sample. One ends of a grouting plug and a stopping plug are topless conical shapes. An exhaust valve is provided on the bottom of a support beam. Thetest system can perform pressure grouting on the sample and monitor the radial deformation. The dual pressure bladder can apply pressure to the lateral and vertical directions of the sample to simulate formation pressure. The silicone gasket and the perforated steel sheet are placed on the upper surface and below surface of the sample to eliminate the end friction effect. The rock/soil was compressed and restored to the initial formation pressure to limit the vertical deformation of the sample. The stress state, the stress path, and the preparation process of the sample are consistent with the actual situation of the anchor, which is suitable for the test of the bonding property between the rock-soil and the anchor under various working conditions.

The invention relates to a mechanical property test device, in particular to a test device for observing the mechanical property of an interface between underwater soil and a structure, which is especially suitable for researching the mechanical property of the interface between the underwater soil and the structure in a hydraulic building (structure). The test device comprises a fixing mechanism, a horizontal movement mechanism, a soil box and a loading system, and an electro-hydraulic servo movable and static universal testing machine is used as a main machine frame. A designed soil material is loaded in the soil box fixed on the horizontal movement mechanism. A structure test block is arranged on an upper chuck of the electro-hydraulic servo movable and static universal testing machine, a normal stress is applied through the vertical loading system, and the shear mechanical behavior of the interface between the underwater soil and the structure under normal stress and complex stress paths can be represented through the horizontal loading system. The normal force and the shear force in the interfere shear test are measured through a load sensor, a vertical displacement meter arranged on the top surface of the structure test sample is used for measuring the normal displacement of the interface in the test, and horizontal displacement meters arranged on two sides of the soil box are used for measuring the shear displacement in the test.

An aging monitor circuit that provides a more accurate estimate of aging and/or delay in a circuit and/or circuit path. The aging monitor circuit employs a separate aging path with driving and receiving flip flops (FFs) and a tunable replica circuit (TRC) to enable measurements of single-transition DC-stressed path delay that only propagates through stressed transistors or other circuit element(s). A finite state machine (FSM) in the aging monitor circuit is configured to adjust a frequency of a clock signal output by a digitally controlled oscillator (DCO) in response to an error signal output by the receiving FF. The error signal is generated in response to single transition DC-stressed path delay, and therefore enables the adjustment of the frequency of the clock signal to correspond to an amount or effect of the delay.

The invention discloses a middle-sized rock servo control true triaxial test device, which comprises a top plate, a base plate, a positioning pillar arranged between the top plate and the base plate, a top force transmission member, at bottom force transmission member, an axial jack arranged under the top force transmission member, a lateral arrow, an upper axial arrow, a lower axial needle arrow, a displacement sensor, a measuring bar matching with the displacement sensor, a computer, a servo control unit, a pulley fixed on the axial jack, a supporting frame for supporting the pulley, a lateral counter-force steel frame arranged surrounding the top of the bottom force transmission member, and a plurality of lateral jacks evenly arranged on periphery of the lateral counter-force steel frame. The device provided by the invention adopts three-dimensional load independent servo control, and can conduct true triaxial test on complex stress path, acquire data automatically and obtain a whole process stress-strain curve.

The invention relates to a rock triaxial direct stretching indoor experimental device. The device includes a base, a confining pressure cylinder, a confining pressure chamber, a confining pressure cover plate, long pull rod bolts, a sample lower base, a fixing screw, a first sealing sleeve, a rock sample, a sample upper base, a sample sealing sleeve, a lateral deformation gauge, an axial deformation gauge, a piston, a confining pressure self-balancing chamber, a tension application chamber, a pull rod, short bolts, a cover body, a confining pressure self-balancing chamber inlet, a tension applying chamber inlet, a communication valve, a confining pressure chamber inlet and a sealing ring. According to the rock triaxial direct stretching indoor experimental device of the invention, appliedrepresentative confining pressure is obtained through calculation according to deep engineering in-situ ground stress; the direct tensile strength and deformation characteristics of rock under different confining pressures can be obtained through the device of the invention, so that the tensile strength criterion of the rock can be obtained through calculation; and therefore, the current cognitiveblank of the tensile strength and mechanical behavior of rock under triaxial tensile stress paths can be filled, the evaluation of the triaxial tensile mechanical strength and deformation behavior ofthe rock is realized, and services can be provided for the safety of deep rock engineering.

The invention relates to a method for measuring a gas permeation coefficient of a compact rock under a three dimensional stress condition, and in particular relates to a test device and a test method for calculating the gas permeation coefficient of the rock by a drawing method by recording a relation between an upstream and downstream pressure difference and time at different moments. The method comprises the steps of preparing a test sample, applying confining pressure, and recording the value. The measurement method is suitable for different types of rocks, such as compact sandstone, granite and shale; the gas permeation coefficients under different confining pressures and different bias pressures and in a triaxial compression breakage process can be measured; gas permeation coefficient test results under all stress paths are compared with that of other conventional test measures to evaluate the reliability and the effectiveness of the device and the method.

The invention discloses a geomaterial complex unloading stress path test method, which comprises the following steps: preparing a geomaterial to be tested; obtaining fundamental physical and mechanical properties and relevant parameters of the geomaterial to be tested; preparing a triaxial sample by the use of the geomaterial to be tested by the adoption of a sample compaction method; successively carrying out sample loading, vacuum saturation and consolidation treatment on the triaxial sample so as to obtain a saturated consolidation sample; setting different unloading stress paths and different unloading stress ratios; carrying out unloading stress path test on the saturated consolidation sample; monitoring and recording changes of stress and strain with stress increment during the test process so as to obtain a macro-mechanical characteristic curve of the saturated consolidation sample; arranging, and respectively calculating unloading modulus, Poisson's ratio, yield locus and yield strength so as to obtain deformation characteristics and strength characteristics of the geomaterial under the condition of complex unloading stress. The invention has the following beneficial effect: stress-strain rules of the geomaterial in the complex unloading stress path state can be obtained.

The invention provides a high-rigidity short stress path rolling mill. According to the high-rigidity short stress path rolling mill, a working machine core is fixed to a movable base; the movable base is connected with a connecting shaft bracket by a hydraulic cylinder; a transverse shifting device is connected with the connecting shaft bracket by a pin shaft; the rolling mill core, the movable base and the connecting shaft bracket all slide on a fixed base; the whole machine line is locked by a locking device on the fixed base; an upper bearing block and a lower bearing block of a roll system device of the working machine core are connected into a whole by four pull rods; the pull rods are fixed to upright posts; the side faces of the upper and lower bearing blocks are clamped between the upright posts of the left and right sides; a guide and guard cross beam is of a box structure; a screw rod is hidden in the guide and guard cross beam; the guide and guard cross beam, an upper cross beam on the machine core and the upright posts form a frame structure. The high-rigidity short stress path rolling mill has the advantages that the integral rigidity is strong, the adjustment range of an opening degree is wide, the service life is long, and the adjustment is convenient.

The invention relates to a frozen clay hollow cylinder sample preparation device. The device has the structural characteristics that a tooth-shaped upper pressure head and a lower pressure head are clamped between an inner cylinder and an outer cylinder in butt joint, are located at the upper end and lower end of a hollow cylinder sample, the outer cylinder is fixed by tightening rings, and a force application rod is right above the toothed upper pressure head, is connected to the pressure head of a sample presser and is responsible for transferring pressure evenly to the toothed upper pressure head. The middle part of the outer cylinder is an ear equipped tightening ring, which is in connection with a stainless steel bracket. The sample preparation method includes: firstly fixing the whole device well, introducing uniformly stirred wet clay into a sample preparation barrel in layers, and performing both-end compaction on the clay body with the sample presser. The device provided by the invention has the advantages of simple operation, time saving and simple principle, can prepare saturated hollow cylindrical clay samples characterized by uniform dry density and moisture content distribution, small initial damage, and tooth-shaped upper surface and lower surface, and provides technical support for further study of the mechanical properties of frozen clay under complex stress path conditions.

The invention discloses a lattice type steel pipe tree-shaped column which is composed of a trunk vertical pipe bundle and branch pipes which are connected, wherein the trunk vertical pipe bundle consists of three-five steel pipes which are arranged uniformly; the adjacent steel pipes are connected through lacing bars; the top end of each steel pipe of the trunk vertical pipe bundle is connected with a first-level branch pipe of which the diameter is smaller than the diameter of the steel pipe; the first-level branch pipe is branched outwards level by level to form a second-level branch pipe like a tree branch; the second-level branch pipe is gradually branched outwards to form a third-level branch pipe like a tree branch; the diameter of the later-level branch pipe is required to be smaller than the diameter of the previous-level branch pipe; the branch pipes are welded together through a multi-jack connecting sleeve during connection, and finally the lattice type steel pipe tree-shaped column is formed. The steel pipe tree-shaped column is light in weight, high in strength, high in bearing force, reasonable in stress path and wide in supporting and covering range, the span of the beam can be greatly reduced, and a large space can be formed by using a small rod piece.

The invention discloses a steel bar arrangement method and a steel bar arrangement device for a reinforced concrete deep beam, relates to the technical field of civil engineering, in particular to the technical field of the steel bar arrangement method for the reinforced concrete deep beam by using compression steel bars. The method comprises the following steps of: arranging a filling block on the part where the reinforced concrete deep beam bears concentrated force; arranging longitudinal tensile steel bars, oblique compression steel bars and other steel bars in the reinforced concrete deep beam, wherein the longitudinal tensile steel bars are arranged along the length direction of two supports and the ends of the longitudinal tensile steel bars correspond to the supports respectively; and one end of each of two groups of oblique compression steel bars is respectively connected with the two ends of each longitudinal tensile steel bar, while the other end is intersected with a position corresponding to the filling block; after all steel bar cages are bound, pouring concrete to make the longitudinal tensile steel bars and the oblique compression steel bars form three-pin rigid frames borne by the supports so as to bear top concentrated load on the filling block. The method and the device realize a clearer stress path and more regular stress distribution in the deep beam; and compared with the conventional steel bar arrangement method, the method can still fulfill the aim of achieving the same bearing capacity under the condition of greatly reducing the number of used steel bars.

The invention discloses a testing instrument and a testing method for detecting the tensile strength of a soil body by using a centrifugal force. The invention aims at actually and really determining and evaluating the tensile strength property of the soil body by using a method for generating a tension force through the high-speed rotation of a soil body test sample. According to the adopted technical scheme, the testing instrument comprises a motor (6), wherein the motor (6) is connected with a soil sample fixing frame (2); the motor (6) can drive the soil sample fixing frame (2) to rotate; the soil sample fixing frame (2) is fixedly provided with a rail for mounting a soil sample and a rail is horizontally arranged; the motor (6) is connected with a computer (5); and the computer (5) can collect the rotary speed of the motor (6) and calculate stress strain and a stress path when the soil sample is damaged, so that the tensile strength of the soil body is determined.

The invention discloses a stress path automatic controlling triaxial apparatus comprising a pressure controlling device, a data measuring and collecting apparatus, a common triaxial apparatus, and a microcomputer. An input terminal of the pressure controlling device is connected to the microcomputer. An output terminal of the pressure controlling device is connected to the common triaxial apparatus for transmitting pressure load. An input terminal of the data measuring and collecting apparatus is connected to the common triaxial apparatus for transmitting analogue signals of displacement, pressure, and volume change. An output terminal of the data measuring and collecting apparatus is connected to the microcomputer for recording data. According to the invention, on a basis of a common triaxial apparatus, a function of a stress path automatic controlling experiment is realized, such that complicated stress path experiments can be carried out. With an additional axial pressurizing cylinder, a tensile experiment can be carried out by using the common triaxial apparatus. During an experiment process, ambient pressure and axial pressure can change automatically, and the measuring and collecting processes of the data are automatic. Therefore, the apparatus provided by the invention is characterized in enhanced function and simple operation.

The present invention relates to a frozen soil hollow cylinder pressure chamber temperature control system. The frozen soil hollow cylinder pressure chamber temperature control system is characterized in that a double helix cold bath circulating slot is carved on the outer wall of a pressure chamber, and the temperature of a pressure-bearing heat-transfer medium in the pressure chamber is reduced circularly in the cold bath circulating slot; an inverted U-shaped copper tube and a temperature sensor are arranged in the inner cavity of a hollow cylinder sample, and three temperature sensors are distributed at the upper, middle and lower positions of the outer wall of the sample; the middle temperature sensor feeds back the temperature data to a cold bath controller while monitoring the temperature change of the middle position, and the upper and lower temperature sensors monitor the temperature fluctuation of the corresponding positions; the pressure chamber is equipped with the upper and lower cooling plates to reduce the heat exchange of the pressure-bearing heat-transfer medium in the inner cavity of the pressure chamber with the outside world, and the temperature of the pressure chamber is adjusted by the cold bath movement in the cooling plates. A frozen soil hollow cylinder apparatus pressure chamber temperature control device of the present invention enables the sample to be cooled rapidly, guarantees the uniform and constant temperature of the sample during the whole test period, is not influenced by the outside world and indoor temperature change, and provides the technical guarantee for revealing the mechanical property of the frozen soil under the action of the complicated stress paths.

A stress-strain measuring device and method for a thin-plate transformation process under a complex stress path are used for solving the problem that under the complex stress path, deformation characteristics of a material cannot be accurately and totally described, which is caused by existing devices and methods that cannot obtain stress-strain data of the plate transformation process under a general complex path loading condition. The stress-strain measuring device for the thin-plate transformation process under the complex stress path comprises a base, a force application mechanism, a liquid-filling pressing plate, an upper template, a glass plate, a ladder concave die, a pressure sensor, a control system, a liquid-filling pressure system, a power system, a CCD camera, and a plurality of supporting blocks and connection rods. The measuring method includes the following steps: (1) manufacturing the ladder concave die and cutting the thin-plate; (2) conducting assembly and liquid filling; (3) conducting plate bulging; (4) acquiring stress-strain information; (5) disassembling the device and saving experimental data. The stress-strain measuring device and method for the thin-plate transformation process under the complex stress path is used for thin-plate stress-strain measurements under the complex stress path.