Abstract

A discrete element method for modelling fracture evolution of roadway surrounding rock is provided, which includes: taking rock cores from a coal seam in the field and recording RQD values, observing roadway deformation, and making a statistical analysis on distribution characteristics of fractures in the coal seam; testing mechanical parameters of coal-rock samples indoors, and calculating strength of a rock mass according to the RQD values; creating a numerical model by using a UDEC-Trigon module to adjust the parameters to match the strength of the rock mass, and correcting model parameters; and creating a numerical model of an engineering scale to adjust the parameters to match field deformation characteristics, and finally simulating fracture evolution of the roadway surrounding rock. The present invention provides accurate and basic mechanical parameters for discrete-element numerical simulation of roadway deformation, guaranteeing realistic and reliable simulation results.

IPC Classes  ?

• G01N 33/24 - Earth materials
• G06F 30/25 - Design optimisation, verification or simulation using particle-based methods
• G01N 3/08 - Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
• G06F 30/23 - Design optimisation, verification or simulation using finite element methods [FEM] or finite difference methods [FDM]
• G06F 30/20 - Design optimisation, verification or simulation
• G06F 111/10 - Numerical modelling

Abstract

A prefabricated stair modular assembly mold comprises a base, a step standard module, an upside module of a lower platform, an underside rotating module of a lower platform, an upside module of an upper platform, an underside rotating module of an upper platform, an underside common module, and an underside adjustment modules. Prefabricated stair molds of different dimensions are formed by means of locating holes provided in the assembling modules, and are then fixed by means of sliding holes at two ends. Further disclosed is a mounting method for said assembly mold. Said assembly mold has high positioning accuracy, and small accumulated error, improving the mounting efficiency of the prefabricated staircase mold.

IPC Classes  ?

• B28B 7/22 - Moulds for making units for prefabricated buildingsMoulds for making prefabricated stair units
• B28B 7/02 - Moulds with adjustable parts
• E04G 13/06 - Falsework, forms or shutterings for particular parts of buildings, e.g. stairs, steps, cornices or balconies for stairs, steps, cornices, balconies, or other parts corbelled out of the wall
• B28B 7/00 - MouldsCoresMandrels
• E04F 11/02 - StairwaysLayouts thereof

Abstract

Disclosed is a discrete element method for simulating the evolution of cracks in rock surrounding a roadway, the method comprising: coring a coal rock layer on-site, recording an RQD value, observing the deformation of a roadway, and compiling distribution features of cracks in the coal layer; testing mechanical parameters of a coal rock sample indoors, and calculating the strength of a rock mass according to the RQD value; using a UDEC-Trigon module to establish a numerical model so as to adjust the parameters to match the strength of the rock mass to correct model parameters; and establishing a numerical model of the scale of a project so as to adjust the parameters to match on-site deformation features to finally simulate the evolution of cracks in rock surrounding the roadway. The present invention provides accurate basic mechanical parameters for the discrete element numerical simulation of the deformation of a roadway, which may guarantee the reliability of a simulation result.

IPC Classes  ?

• G06F 17/50 - Computer-aided design

Abstract

Provided is a rational width determination method for a gob-side entry driving narrow coal pillar based on crack evolution. The method comprises five steps of: observing roadway deformation and coal pillar crack distribution characteristics on site; constructing a UDEC-Trigon numerical model to match an on-site condition to determine model parameters; inverting an evolution law of inner cracks of coal pillars with different widths; determining rational coal pillar widths on the basis of crack evolution penetration; and finally providing high pre-stressed anchor and anchor cable technology to control the stability of the coal pillars. In the method, by using a damage factor for quantifying and assessment of crack evolution penetration to finally determine the optimal rational width of gob-side entry driving narrow coal pillars, it is ensured that inner cracks of the coal pillars within a service period are not penetrated, and gas in a goaf can be isolated effectively while the coal pillars are borne stably.

IPC Classes  ?

• E21F 7/00 - Methods or devices for drawing-off gases with or without subsequent use of the gas for any purpose
• E21C 41/18 - Methods of underground miningLayouts therefor for brown or hard coal
• E21B 43/26 - Methods for stimulating production by forming crevices or fractures

Abstract

An apparatus for protecting a roof tray when a gob-side entry retaining end support migrates is provided. The apparatus is mounted at a top end position of a hydraulic support, and includes a movable bearing mechanism, an automatic expansion/contraction connecting groove mechanism, and an active reset mechanism. The movable bearing mechanism includes two parallel belts and a plurality of rollers supporting the belts, and the rollers are mounted on and supported by a bearing mechanism. The automatic expansion/contraction connecting groove mechanism is two concave base plates fixed between the two belts, and the two concave base plates are spaced by a distance. The active reset mechanism includes two telescopic rods and reset springs sleeved on the telescopic rods, and the telescopic rod is connected to an end portion of the reset spring to form a synchronous mechanism.

IPC Classes  ?

• E21D 23/08 - Advancing mechanisms
• E21D 23/04 - Structural features of the supporting construction, e.g. linking members between adjacent frames or sets of propsMeans for counteracting lateral sliding on inclined floor

Abstract

An apparatus for protecting a top plate tray during gob-side entry retaining end bracket migration, mounted at the top end of a hydraulic bracket, and comprising a mobile pressure-bearing mechanism, an automatic extension connecting groove mechanism, and an active reset mechanism, the pressure-bearing mechanism comprising two parallel caterpillar tracks (4) and a plurality of rollers (5) supporting the caterpillar tracks (5), the rollers being mounted and supported by bearing mechanisms (10); the automatic extension connecting mechanism is two sets of concave chassis (8) fixed between the two caterpillar tracks, the two sets of concave chassis being spaced apart a certain distance; and the active reset mechanism comprises two telescopic rods (3) and a reset spring (2) sleeved over each telescopic rod, the ends of the reset spring and the telescopic rod being connected to form a synchronisation mechanism, one end of both being collectively connected to one side of the concave chassis, and the other end being fixed at the end of the hydraulic bracket by means of a fixing support base (1). The present apparatus protects the exposed tray and part of the anchor rod or anchor cable structure during the bracket migration process, balances the force acting on the roadway top plate during the moving process, and can automatically reset when the bracket retracts.

IPC Classes  ?

• E21D 23/04 - Structural features of the supporting construction, e.g. linking members between adjacent frames or sets of propsMeans for counteracting lateral sliding on inclined floor
• E21D 23/16 - Hydraulic or pneumatic features, e.g. circuits, arrangement or adaptation of valves, setting or retracting devices
• E21D 15/55 - Details of the ends of props of prop heads

Abstract

A beam-column non-open-hole connection node of a modular steel structure building and an assembly method. A positioning cylinder is fixed at a lower part of an inner wall of a beam-column. A positioning plate is fixed at an upper end of the positioning cylinder. A lower end plate is fixed at a lower end of the beam-column, and an upper end plate is fixed at an upper end of the beam-column. A bolt is located in the positioning cylinder, the bolt has external threads, the upper end plate has a threaded hole, and a middle part of the lower end plate has a hole. The beam-column non-open-hole connection node of the modular steel structure building and the assembly method of the present invention have a simple structure, a wide application, and convenient construction; no additional bolts are needed, a bolt penetrates a liner plate to connect upper and lower modules, and then the liner plate and the bolt may connect horizontal modular steel structures at the front, rear, left and right as a whole; a bolt reserved in the beam-column may be connected by means of the tightening of a long rod torsion tool to connect adjacent beam-columns at end surfaces, and the torsion tool may be pulled out after screwing; the installation is convenient and the weight of the modular steel structure is reduced; and eight modules at most may be connected together and may be applied to each node of the modular building.

IPC Classes  ?

• E04B 1/24 - Structures comprising elongated load-supporting parts, e.g. columns, girders, skeletons the supporting parts consisting of metal
• E04B 1/58 - Connections for building structures in general of bar-shaped building elements

Abstract

A prefabricated assembled staircase modular assembly mold, comprising a base (1), standard step modules (3), a lower platform upper surface module (2), a lower platform lower surface rotation module (6), an upper platform upper surface module (4), an upper platform lower surface rotation module (5), a lower surface general module (7), and lower surface adjustment modules (8); prefabricated staircase molds of different dimensions are formed by means of size positioning holes (12) provided in the assembling modules, and are then fixed by means of sliding holes (11) at two ends. Further disclosed is a mounting method for said assembly mold. Said assembly mold has high positioning accuracy, and small accumulated error, improving the mounting efficiency of the prefabricated staircase mold.

IPC Classes  ?

• E04G 13/06 - Falsework, forms or shutterings for particular parts of buildings, e.g. stairs, steps, cornices or balconies for stairs, steps, cornices, balconies, or other parts corbelled out of the wall

Abstract

The present invention discloses a blind bolt fastening device, and belongs to the technical field of bolts. The blind bolt fastening device includes Z-shaped gaskets, a fixed plate, elastic hinges, a screw cap, a nut, an integrated gasket and the like. The top end of the screw cap is connected to the fixed plate in a spot welding manner. A plurality of elastic hinges is uniformly mounted on the fixed plate. One end of each elastic hinge is rotatably fixed on the fixed plate. Connection points of the elastic hinges and the fixed plate do not exceed the outer edge of the fixed plate. The other end of each elastic hinge is connected to one Z-shaped gasket in a spot welding manner. In an initial state, the plurality of Z-shaped gaskets are uniformly distributed and fitted onto the outer wall of the screw cap along a circumferential direction. When needing to pass through amounting hole, the plurality of Z-shaped gaskets may be folded through the elastic hinges to the top end of the screw cap and form elastic potential energy for rebounding. The present invention realizes simple and quick single side installation of a bolt and may be widely applied to civil and architectural engineering, mechanical engineering and the like.

IPC Classes  ?

• F16B 35/06 - Specially-shaped heads
• F16B 37/00 - Nuts or like thread-engaging members
• F16B 39/28 - Locking of screws, bolts, or nuts in which the locking takes place during screwing down or tightening by special members on, or shape of, the nut or bolt
• F16B 19/10 - Hollow rivetsMulti-part rivets fastened by expanding mechanically
• F16B 41/00 - Measures against loss of bolts, nuts, or pinsMeasures against unauthorised operation of bolts, nuts, or pins
• F16B 43/00 - Washers or equivalent devicesOther devices for supporting bolt-heads or nuts

Abstract

A one-side bolt fastening device relating to the technical field of bolts, and comprising Z-shaped gaskets (1), a fixing plate (2), elastic hinges (3), a screw cap (4), a nut (5), and a solid gasket (6). The top end of the screw cap (4) is in spot-welded connection to the fixing plate (2); multiple elastic hinges (3) are uniformly installed on the fixing plate (2); one end of each of the elastic hinges (3) is rotatably fixed to the fixing plate (2); the connecting points at which the elastic hinges (3) are connected to the fixing plate (2) do not go beyond the outer edge of the fixing plate (2); the other end of each of the elastic hinges (3) is connected with one Z-shaped gasket (1) in a spot-welded mode; the multiple Z-shaped gaskets (1) in an initial state are attached to the outer wall of the screw cap (4) in a circumferential direction; when a bolt needs to penetrate through an installation hole (7-1), the multiple Z-shaped gaskets (1) can be turned over to the top end of the screw cap (4) by means of the elastic hinges (3) and form an elastic potential energy of resilience, thus achieving simple and rapid one-side bolt installation. The device can be widely used for civil construction engineering, mechanical engineering and the like.

IPC Classes  ?

• F16B 35/06 - Specially-shaped heads
• F16B 43/00 - Washers or equivalent devicesOther devices for supporting bolt-heads or nuts

Abstract

A bag-shaped filling structure for an underground coal mine and a use method therefor. The bag-shaped filling structure for an underground coal mine comprises a truss beam wall (3), a surface sealing layer of a bag-shaped structure, and a bottom structure (4); the truss beam wall (3) is formed by stacking truss beam frames, the truss beam frame is formed by connecting, end-to-end, truss beam assemblies (2) having four identical sides, and each row of truss beam assemblies (2) is formed by connecting a plurality of truss beam elements (1) side by side; the truss beam wall (3) is fixedly connected between an inner surface sealing layer (7) and an outer surface sealing layer (8) of the surface sealing layer of a bag-shaped structure, and is mounted on the bottom structure (4).

IPC Classes  ?

• E21F 15/02 - Supporting means, e.g. shuttering, for filling-up materials
• E21F 15/00 - Methods or devices for placing filling-up materials in underground workings
• E21D 20/00 - Setting anchoring-bolts