228 results about "Radial stress" patented technology

The invention provides an aviation fastener service life prediction method and system based on stress analysis, and the method comprises the steps: collecting a dynamic stress data set of a target fastener in a service environment, carrying out the three-dimensional stress field reconstruction of the dynamic stress data, and obtaining a three-dimensional stress field model; the method comprises the following steps: generating stress distribution characteristics including an axial stress gradient, a radial stress cumulant and a tangential stress fluctuation coefficient, and then calling a pre-trained life prediction model to carry out nonlinear degradation analysis on the stress distribution characteristics to obtain a residual life prediction value and a key failure area identifier of a target fastener. Further, on the basis of the incidence relation between the temperature fluctuation sequence and the material thermal expansion coefficient, service environment compensation correction is conducted on the residual life prediction value, and finally, a fastener maintenance strategy set containing a stress release path adjustment scheme and a surface strengthening treatment scheme is generated according to the key failure area identifier; and precise prediction and effective maintenance of the service life of the aviation fastener are realized.

The invention discloses a positive screw pile foundation axial ultimate uplift bearing capacity calculation method. The method comprises the steps that a pile-soil interface contact normal pressure stress function and a contact tangential friction stress function are constructed; constructing an equivalent relationship between the uplift resistance on the right-hand screw pile drawing surface and the shear resistance on the cylindrical shear failure surface of the foundation soil body, and obtaining the horizontal force and the circumferential torque of the soil body acting on the right-hand screw pile drawing surface; obtaining an equivalent concentrated load of a horizontal force and an action point location thereof; the radial load of the foundation soil body acting on the right-hand screw pile drawing face is obtained, and the additional radial stress on the cylindrical shear failure face in the foundation soil body is obtained; obtaining application conditions of an additional shear resistance calculation formula according to an additional radial stress limit summation calculation formula; and a positive screw pile foundation axial ultimate uplift bearing capacity calculation formula is constructed, and the positive screw pile foundation axial ultimate uplift bearing capacity calculation formula is obtained. The problem that the axial ultimate uplift bearing capacity of the positive screw pile foundation cannot be accurately obtained through an existing method is solved.

The invention relates to the technical field of tunnel surrounding rock stability control, and provides an excavation compensation method for a deep tunnel. The method comprises the following steps: acquiring engineering geological information of the deep tunnel; determining an engineering disaster type based on the engineering geological information; determining an excavation compensation support strategy of the deep tunnel surrounding rock based on the engineering disaster type; and performing supplementary support control on the surrounding rock of the deep tunnel based on the excavation compensation support strategy. The difference value between the radial stress and the initial ground stress of the deep tunnel surrounding rock can be reduced to be within the preset approximate value range through the supplementary supporting strategy, and the stress concentration phenomenon of the tangential stress can be further effectively prevented. After the deeply-buried tunnel is excavated, high-prestress excavation compensation support is applied in time, the three-dimensional initial stress state of the surrounding rock is recovered as much as possible, and therefore the bearing capacity of the surrounding rock is improved, the deep rock mass strength is fully improved, and effective control over the deeply-buried tunnel surrounding rock is achieved.

The present disclosure relates to the technical field of stability control of surrounding rock of tunnelling, and provides an excavation compensation method for tunnelling in deep rock engineering, including: acquiring an engineering geological information of the tunnelling in deep rock engineering; determining an engineering hazard type based on the engineering geological information; determining an excavation compensation support strategy for the surrounding rock of the tunnelling in deep rock engineering based on the engineering hazard type; and performing a supplementary support control on the surrounding rock of the tunnelling in deep rock engineering based on the excavation compensation support strategy. Through the supplementary support strategy, the difference value between a radial stress of the surrounding rock of the tunnelling in deep rock engineering and an initial crustal stress can be reduced to within a preset approximate value range, further effectively preventing a stress concentration phenomenon occurred in a tangential stress.

The invention discloses a tension-free wrapping system and method for an armored spiral tube superconducting coil for nuclear fusion, which is suitable for the field of research, development and manufacturing of nuclear fusion reactors, and comprises a wrapping platform upper cover plate, a first laser level meter, a cylinder positioning rod, a slewing bearing platform, a second laser level meter, a cushion block and a wrapping platform, the slewing bearing platform rotates according to the radial stress condition of a superconducting coil turn-releasing coil and the stress condition of a spiral line in the circumferential direction, and the second laser level meter rotates according to a base of the wrapping platform and then conducts lead-out datum line positioning calibration. And a cylinder positioning rod arranged on the wrapping platform is used for positioning and fixing the slewing bearing platform of the wrapping platform. According to the invention, the tension-free insulation wrapping of the armored spiral tube superconducting coil for nuclear fusion can be ensured, and the tension damage of the metallographic structure of the superconducting coil in the wrapping process is avoided.

The invention discloses a spiral bevel gear grinding force measuring method and system, electronic equipment and a medium, and the method comprises the steps: obtaining the measuring force in the X, Y and Z directions through a fixed dynamometer, and determining the installation angle of the fixed dynamometer according to the obtained measuring force in the X, Y and Z directions; based on the installation angle, determining a target coordinate transformation matrix between the fixed dynamometer and the gear grinding machine tool cutter shaft; calculating an axial stress component and a radial stress component of the cutter shaft of the gear grinding machine tool according to the measured measuring forces in the X, Y and Z directions and the target coordinate transformation matrix; tool setting between the spiral bevel gear workpiece and the grinding wheel tool is completed based on the axial stress component and the radial stress component; the target relative position of the grinding wheel tool and the gear grinding machine tool workpiece shaft is obtained; and according to the target relative position, the cutting force component of the grinding force and the normal force component of the grinding force are calculated. The precision of grinding force measurement of the spiral bevel gear can be improved.

The invention discloses a TBM hob three-way rock breaking force prediction method and system based on a rotary cutting mode, and the method comprises the steps: building a hyperbolic function model of the cutting edge width and penetration depth of a hob, and optimizing the geometric structure of the hob to adapt to different rock stratums; an effective contact radius and a contact angle are calculated through a coupling motion trail equation of revolution and rotation of the hob; fitting a pressure distribution coefficient in combination with pre-test data, constructing a Hertz-Weibull stress coupling analysis model, and accurately representing stress distribution in the cutting direction and the radial direction; on the basis of contact pressure integration and stress decomposition, respectively deriving explicit calculation formulas of vertical, rolling and lateral rock breaking forces, and dynamically adjusting the rotating speed of the cutterhead, the propelling pressure and the hob spacing according to a rock breaking force prediction result. According to the method, the rock breaking force prediction precision in the complex rock stratum is remarkably improved, the TBM construction efficiency and the cutter service life are optimized, the over-excavation risk and energy consumption are reduced, and the method is suitable for intelligent tunneling control of tunnel engineering.

The invention relates to the technical field of cables, and discloses a high-voltage cable with high safety performance. The cable comprises a conductor, a conductor shielding layer, an insulating layer, an insulating shielding layer, an inner buffer layer, a protective layer, a reinforced steel cable, an outer buffer layer and an outer protective layer which are sequentially and coaxially arranged from inside to outside. The protective layer is composed of a plurality of sets of protective units arranged in an array mode in the axial direction, and each protective unit is of an annular structure defined by a plurality of protective pieces in the circumferential direction. The inner wall and the outer wall of the protection piece are arc-shaped, steel cable grooves are formed in the two sides of the protection piece, and hollow grooves are formed in the protection piece; the multiple protection units are in staggered butt joint to form a continuous spiral surrounding structure. And the reinforcing steel cable is spirally wound and embedded in a spiral channel formed by the steel cable grooves of the protective sheets. Uniform conversion and dispersion from axial tension to radial stress are realized, the design of the rhombic protection sheets and the hollowed-out grooves is combined, the tensile resistance, extrusion resistance, impact resistance and cutting resistance of the cable are remarkably improved, and the cable is suitable for a complex laying environment.

The invention discloses a fractured formation horizontal well wall stability quantitative control method under transient temperature and pressure coupling, and relates to the technical field of deep oil and gas drilling. The method comprises the following steps: analyzing the internal temperature of a drill column, the annulus temperature and the well wall temperature reflecting the transient temperature difference disturbance boundary effect by utilizing a drilling process API RP 13D rheological drilling fluid circulating temperature field control equation; establishing a dynamic ECD prediction model coupled with the annulus temperature and the pressure disturbance effect, and taking the transient temperature difference between the dynamic temperature of the well wall and the original temperature of the stratum, the transient pressure difference between the transient pressure of the well wall and the original pore pressure of the stratum and the transient stress difference between the transient pressure of the well wall and the original radial stress as dynamic disturbance boundary conditions; a pore pressure field and a stress field of rock around a well of the fractured formation under the heat-fluid-solid coupling effect under the non-uniform ground stress condition are analyzed in combination with a dual-pore thermoelasticity theory, a safe density window of the horizontal well of the fractured formation is determined, and well wall instability can be effectively prevented.

The present application belongs to the technical field of SiC production and processing. Disclosed are an SiC substrate having uniform stress distribution in a three-dimensional direction, and an SiC crystal. The SiC substrate comprises a first surface layer, a second surface layer and an intermediate layer, wherein on the same axis, at any plane parallel to a first main surface or a second main surface in the first surface layer, Smax1 represents the maximum value of an absolute value of a radial stress in the first surface layer, Smax2 represents the maximum value of an absolute value of a radial stress in the intermediate layer, Smax3 represents the maximum value of an absolute value of a radial stress in the second surface layer, ΔS1=Smax2-Smax1, ΔS2=Smax2-Smax3, -15 MPa≤ΔS1≤10 MPa, and -15 MPa≤ΔS2≤10 MPa. The radial stresses in the SiC substrate in all of the first surface layer, the second surface layer and the intermediate layer are relatively low, the stress distribution uniformity among the layers is good, so that the quality of the SiC substrate can be improved, the usage range of the SiC substrate is expanded, and the production and processing of downstream epitaxial wafers and crystals are facilitated.

The invention discloses a motor no-load and radial stress test method, which comprises the following steps of: installing a target product on a positioning carrying table, providing a forward rotation or reverse rotation excitation signal for the target product, and enabling a middle carrying table to be in a flexible connection state; starting an audio acquisition assembly to detect noise, and abutting an accelerometer against the target product to detect vibration; controlling the accelerometer to stop vibration detection, and controlling the intermediate platform deck to be switched to a rigid connection state; preset radial thrust is applied to a rotating shaft of the target product through a radial thrust mechanism, radial thrust monitoring is conducted through a second pressure detection assembly, and the radial thrust mechanism is installed on the first sliding table, located on the adjacent side of the positioning carrying table and connected with the second pressure detection assembly. The device can be switched between a no-load working condition and a radial stress working condition, so that continuous testing of multiple functions can be realized.

The invention discloses a method for rapidly and accurately judging a blasting vibration safety allowable distance, and belongs to the technical field of geotechnical engineering blasting. The method specifically comprises the steps of establishing a simplified mathematical model of explosive wave propagation and an explosive wave propagation control equation; basic mechanical parameters of rocks of the blasting engineering are obtained; obtaining a blast hole wall stress wave action time history curve; solving the explosion wave propagation control equation to obtain a radial stress complex variable function and a mass point displacement complex variable function at any moment around an explosion source; obtaining a radial stress time domain variable function and a mass point vibration velocity function; constructing a characteristic function relationship between a radial stress peak value and a mass point vibration velocity peak value, introducing a peak value stress wave propagation attenuation function, finally obtaining a mass point peak value vibration velocity, and drawing a mass point peak value vibration velocity distribution curve; and the blasting vibration safety allowable distance is obtained. According to the method, the blasting vibration safety allowable distance conforming to the specification can be rapidly and accurately calculated, the calculation efficiency is high, and the prediction result is accurate.

The utility model discloses a motor correction device which comprises a rack, an auxiliary structure and a test structure. The rack is provided with a mounting surface, a through first through hole is formed in the mounting surface, the auxiliary structure comprises a clamping assembly, and the clamping assembly has linear motion close to or away from the mounting surface; the testing structure comprises a clamp and a driving assembly, the driving assembly is in driving connection with the clamp, the end face of the clamp faces the first through hole, the clamp is provided with a movable clamping groove, the movable clamping groove is used for clamping and centering the output shaft, and the driving assembly drives the clamp to rotate and drives the output shaft to rotate so as to achieve rotation precision correction of the tested motor. According to the technical scheme, the rack provides an installation base, the testing structure and the auxiliary structure are both installed on the rack, during correction, the movable clamping groove clamps the output shaft of the tested motor, the output shaft is made to be coaxial with the driving center of the driving assembly, the situation of radial stress of the output shaft in the testing process is reduced, and the testing efficiency is improved. And the correction accuracy and consistency of the device are improved.

The invention relates to a winding short-circuit performance evaluation method and device based on a reactor model, computer equipment, a computer readable storage medium and a computer program product. The method comprises the steps of simulating operation of a reactor model under a preset short-circuit working condition to obtain magnetic flux leakage distribution on a coil winding in the reactor model; determining a magnetic flux leakage component of an outlet wire of the coil winding based on a preset short-circuit working condition, the reactor model and the magnetic flux leakage distribution, and determining a simulated radial electrodynamic force of the outlet wire based on the magnetic flux leakage component; based on the reactor model, determining the theoretical radial bearing force of the leading-out wire; determining a radial bearing capacity parameter of the head wire according to the simulated radial electrodynamic force and the theoretical radial bearing capacity, and obtaining a radial stress performance evaluation result of the coil winding based on the radial bearing capacity parameter. Compared with the prior art, through comparison calculation of the simulation value and the theoretical value, potential safety hazards possibly existing in the reactor can be found in advance, and measures can be taken in time for prevention.

The invention provides a tunnel face rock mass stability evaluation method and device based on three-dimensional reconstruction, and relates to the technical field of underground civil engineering, the tunnel face of a rock mass to be evaluated is divided through a three-dimensional grid, points to be measured are arranged in each evaluation area, the maximum horizontal stress, the minimum horizontal stress and the vertical stress of each point to be measured are calculated, and the stability of the tunnel face rock mass is evaluated. Calculating a stress value of a central point of a to-be-evaluated area according to the data, comprehensively generating primary rock stress of the to-be-evaluated area of the rock mass tunnel face, monitoring mining-induced stress, decomposing the stress into axial stress, circumferential stress and radial stress, further generating a stress threshold value, and calculating the stress value of the to-be-evaluated area by setting a safety threshold value and counting the number of the areas with the stress exceeding or not exceeding the threshold value. And calculating a safety coefficient, and judging whether the tunnel face rock mass is stable or not. Through the three-dimensional reconstruction technology and the stress contact method, accurate evaluation and safety judgment of the stability of the rock tunnel face are achieved.

The invention discloses a construction period surrounding rock-support system cooperative bearing analysis method, which is characterized in that the radial stress release process of the tunnel inner wall surrounding rock in the construction period is divided into n calculation steps, and after a support system is constructed, each calculation step comprises a preliminary approach analysis stage and a precise convergence analysis stage; in the initial approaching analysis stage, the displacement increment of the ith calculation step is utilized to estimate the support load increment of the (i + 1) th calculation step, and the stress, strain and displacement of the surrounding rock are solved; if the absolute value of the difference value of the surrounding rock displacement and the support displacement is smaller than a set error threshold value, calculation is ended; otherwise, entering a precise convergence stage to correct the support load. The method has the advantages that the complex iterative calculation process in the traditional dichotomy is simplified, and the solving process of the surrounding rock-support system is divided into two stages of preliminary approaching and accurate convergence. The calculation times are obviously reduced, and the calculation precision is ensured.

The embodiment of the invention provides a rock eccentricity non-coupling charge blasting cracking evaluation method, device and equipment and a computer readable storage medium. The method comprises the following steps: acquiring working condition parameters; inputting the working condition parameters into a constructed eccentric non-coupling charge blasting fracturing evaluation model to obtain a fracture eccentric distribution range; wherein the eccentric non-coupling charge blasting cracking evaluation model can be constructed by the following steps: acquiring initial pressure of each point of a rock blasting hole wall and stress characteristic conditions on a damage conjugate surface; calculating the radius of the crushing area of each point of the hole wall based on the stress characteristic condition on the damaged conjugate surface and the initial pressure; and on the basis of the radius of the crushing area of each point of the hole wall and the obtained radial stress and circumferential stress characteristics of the fracture area, an eccentric uncoupled charge blasting fracturing evaluation model is constructed. In this way, the eccentric distribution range of rock blasting cracking can be effectively evaluated, and theoretical guidance is provided for blast hole scheme design.

The present application discloses a SiC substrate and a SiC crystal with uniform three-dimensional directional stress distribution, belonging to the technical field of SiC production and processing. The SiC substrate includes a first surface layer, a second surface layer and an intermediate layer; on the same axis, at any plane parallel to the first main surface or the second main surface in the first surface layer, Smax1 represents the maximum absolute value of the radial stress in the first surface layer, Smax2 represents the maximum absolute value of the radial stress in the intermediate layer, Smax3 represents the maximum absolute value of the radial stress in the second surface layer, △S1 = Smax2 - Smax1, △S2 = Smax2 - Smax3, -15 MPa ≤ △S1 ≤ 10 MPa, -15 MPa ≤ △S2 ≤ 10 MPa. The radial stress in the SiC substrate in the above first surface layer, second surface layer and intermediate layer is relatively low, and the stress distribution uniformity between each layer is good, which can improve the quality of the SiC substrate, expand the use range of the SiC substrate, and is beneficial to the production and processing of downstream epitaxial wafers and crystals.

Provided is a sealing assembly, a well system, and a method. The sealing assembly, in one aspect, includes a mandrel, and a sealing element positioned about the mandrel. The sealing element, in this aspect, includes a cylindrical protective sleeve positioned about the sealing element, the cylindrical protective sleeve configured to break to deploy from an undeployed state to a deployed state based upon axial or radial stress imparted thereon.

The invention discloses motor testing equipment which comprises a base, a middle carrying table, a radial thrust mechanism, a torque sensor, a first pressure detection assembly, an accelerometer and a displacement sensor. The damping member and the at least two clamping members can realize switching between flexible connection and rigid connection of the intermediate platform deck, test conditions under different working conditions are satisfied, the radial thrust mechanism can apply radial thrust to a rotating shaft of a target product, and the radial thrust mechanism cooperates with the second pressure detection assembly to realize a radial stress working condition test. The sliding table driving mechanism can drive the second sliding table to move relative to the first sliding table, axial force is applied to a target product through the torque sensor, axial stress working condition testing is achieved in cooperation with the first pressure detection assembly, and data collection can be conducted through the torque sensor, the photoelectric sensor, the accelerometer and the displacement sensor in the testing process. The integrated level is high, and multiple functions of the motor can be continuously tested.

The invention discloses an underground diaphragm wall annular rigidity calculation method and system, electronic equipment and a storage medium, and the method comprises the steps: S100, collecting a design scheme and related parameters of a circular underground diaphragm wall structure, enabling the space annular effect of a circular underground diaphragm wall to be equivalent to a distribution spring which deforms under stress along the radial direction, and calculating the annular rigidity of the circular underground diaphragm wall according to the coordination of annular deformation and radial deformation; obtaining an equivalent distribution elastic support coefficient of the circular wall circumferential effect; s200, according to the distribution condition of groove section concrete and joint mud cakes in the underground diaphragm wall structure, the annular rigidity reduction coefficient is determined; s300, describing the nonlinear compression characteristics of the joint mud cake, and determining the initial stress-strain state of the concrete and the mud cake of the diaphragm wall before excavation; and S400, a transcendental equation is established according to the stress-strain relation between the concrete and the mud cake, and the equivalent elastic modulus and the circumferential rigidity reduction coefficient of the diaphragm wall are solved. By considering the nonlinear compression characteristic of the joint mud cake, the rule that the circumferential rigidity of the diaphragm wall is increased along with the increase of deformation is described more accurately.

The application discloses a high-performance motor rotor core, comprising rotor laminations, wherein a plurality of magnetic steel slot groups are arranged on the rotor laminations in a circumferential direction; the application has simple structure and reasonable design; stress reduction structures with central symmetry characteristics are arranged to effectively guide and release main radial stress in the magnetic bridge area, optimize stress distribution, avoid fatigue cracks caused by local stress concentration, improve fatigue life and structural safety margin of the magnetic bridge, and improve NVH performance, reduce electromagnetic harmonics, and improve stability and quietness of motor operation; in addition, the overall magnetic steel slot layout is optimized to realize reasonable reduction of material use and lightweight design of the rotor core, and improve power density and dynamic response capability under the premise of guaranteeing electromagnetic performance.

The invention discloses a method and a device for determining safe service time of a casing pup joint, a medium and electronic equipment. The method comprises the steps that according to the current geological condition of an injection and production well, the position of surface water connected with a casing pipe pup joint is judged, and the position of the surface water is set as the corrosion core position of the casing pipe pup joint; calculating the total radial stress, the total circumferential stress and the total axial stress corresponding to the corrosion core position under the initial time node so as to calculate the equivalent stress corresponding to the corrosion core position under the initial time node; and according to the equivalent stress and the yield strength, the safe service time of the casing pup joint is determined. According to the method, the accuracy of calculating the safe service time of the casing pup joint can be improved.

The invention discloses a method for determining the stress of a circular film under a transversely uniformly distributed load, which comprises the following steps of: applying a transversely uniformly distributed load q to a circular film which is flat before deformation, has the periphery fixedly clamped, the radius a, the thickness h, the Young's modulus E and the Poisson ratio v, and determining the stress of the circular film under the transversely uniformly distributed load q; when the circular thin film is subjected to axial-symmetry deformation, axial-symmetry deflection deformation can be generated in the direction of the load q, and based on static equilibrium analysis of the axial-symmetry deformation problem of the circular thin film, the radial stress sigma r (r) and the circumferential stress sigma t (r) of the circular thin film after axial-symmetry deformation can be determined by utilizing the measured value of the load q.

The invention discloses a method and device for determining the safe service time of a production pipe column, a medium and electronic equipment. The method comprises the steps that the corrosion core position is determined according to the injection-production working condition of an injection-production well, and the corrosion core position is the position corresponding to the maximum gas partial pressure of a production pipe column; calculating an equivalent stress corresponding to the corrosion core position by calculating a total radial stress, a total circumferential stress and a total axial stress corresponding to the corrosion core position; and according to the equivalent stress and the yield strength corresponding to the production pipe column, the safe service time of the production pipe column is determined. The accuracy of calculating the safe service time of the production pipe column can be improved.

The invention provides a combined pipe pile which comprises a stand column, a plurality of first fixing ribs and a plurality of second fixing ribs are arranged in the stand column and perpendicularly connected to form a first fixing net, the first end of the stand column is used for fixing a tower foot of a base station tower, and the second end of the stand column is used for fixing a second fixing net. The first fixing net is used for bearing part of radial stress and part of axial stress of the stand column. The second end of the stand column is fixedly connected with the first surface of the bottom table, the orthographic projection of the stand column is located in the first surface, a plurality of third fixing ribs and a plurality of fourth fixing ribs are arranged in the bottom table, and the third fixing ribs and the fourth fixing ribs are perpendicularly connected to form a second fixing net. The second fixing net is used for bearing part of radial stress and part of axial stress of the bottom table; and the single pipe pile is fixedly connected with the second surface of the bottom table, the orthographic projection of the single pipe pile is in the second surface, and the single pipe pile is used for being buried in a soil layer to a set depth so as to bear the radial stress and the axial stress of the combined pipe pile.

The application relates to the technical field of cables, and discloses a high-voltage cable with high safety performance. The cable comprises, from inside to outside, a conductor, a conductor shielding layer, an insulation layer, an insulation shielding layer, an inner buffer layer, a protective layer, a reinforcing steel cable, an outer buffer layer and an outer protective layer; the protective layer is composed of multiple groups of protective units arranged in an axial array, each protective unit is formed into a circular ring structure by multiple protective sheets arranged in a circumferential direction, the cross section of the protective sheet is in a prismatic shape, the inner and outer walls are in arc shapes, steel cable grooves are arranged on the two sides, and a hollow groove is arranged in the interior; the multiple protective units are staggered and connected to form a continuous spiral winding structure; and the reinforcing steel cable is spirally wound and embedded in the spiral channel formed by the steel cable grooves of the protective sheets. The application realizes uniform conversion and dispersion of axial tension into radial stress, and combines the design of the rhombic protective sheet and the hollow groove, so that the tensile resistance, extrusion resistance, impact resistance and cutting resistance of the cable are significantly improved, and the cable is suitable for complex laying environments.

The invention discloses a seismic data-based pre-drilling evaluation method and device for vertical well wall stability. The method comprises the following steps of: obtaining related data of pre-drilling well drilling design of a target well; pre-stack and post-stack seismic inversion is carried out, and stratum elastic parameters of the target well position are obtained; calculating formation pressure and ground stress parameters of the target well position based on the formation elastic parameters; obtaining the strength parameter, cohesion and internal friction angle of the stratum rock at the target well position through a rock physical test experiment or based on the stratum elastic parameters; carrying out numerical simulation on the stability of the well wall around the well to obtain vertical stress, tangential stress and radial stress in different directions around the well; and analyzing the magnitude relationship of the vertical stress, the tangential stress and the radial stress along different directions of the well circumference so as to judge the tensional failure and the shear failure possibly occurring around the well circumference in the drilling process, and completing the pre-drilling evaluation of the well wall stability of the drilling well. According to the method, the pre-drilling evaluation of the vertical well wall stability can be realized.

The present application relates to the technical field of coal mine equipment, and discloses a self-moving device and a hydraulic system thereof, which comprises a base provided with sliding rails, two sliding bodies sliding along the sliding rails, two locking mechanisms respectively arranged on the sliding bodies and a driving mechanism connected between the two sliding bodies; wherein the locking mechanism is installed on the sliding body through a first hinged mechanism and cooperates with a limiting block to perform floating limiting, and the two ends of the driving mechanism are connected with the sliding bodies through a second hinged mechanism; each mechanism cooperatively acts to realize step-by-step displacement through alternating locking and driving. The present application realizes non-rigid connection through floating limiting of the hinged mechanism and the limiting block, automatically compensates the perpendicularity and position deviation between the base and the sliding body, releases radial stress, effectively prevents damage of the locking mechanism and the driving mechanism caused by unbalanced load, and ensures the stability and reliability of step-by-step displacement of the device.

The invention relates to the technical field of civil engineering, and particularly discloses a tunnel rock anchor bearing arch numerical calculation method considering mechanical parameter changes of surrounding rock, which comprises the following steps: establishing a tunnel rock anchor bearing arch numerical calculation model to carry out numerical calculation in the ith step; traversing all units in the model; extracting a corresponding stress component and a centroid coordinate of each unit and then calculating a radial stress of each unit; calculating a mechanical parameter update value of each unit; judging whether each unit participates in numerical calculation of the ith step or not; if so, endowing the unit with updated mechanical parameters, otherwise, keeping the mechanical parameters unchanged; judging whether the i-step numerical calculation of the numerical model is converged or not; if convergence occurs, the calculation process is ended, and otherwise, numerical calculation of the (i + 1) th step is carried out. According to the method, in the numerical calculation process of the tunnel rock anchor bearing arch, the change of surrounding rock mechanical parameters along with the change of surrounding rock stress is considered, reference is provided for the design of tunnel engineering supported by anchor rods, and the method has good engineering value.