141 results about "Pre cracking" patented technology

The invention discloses a carbon dioxide mining device. The carbon dioxide mining device comprises an energy release head, a fixed pressure energy release sheet, a main pipe and a filling head, wherein the energy release head and the filling head are respectively fastened at the two ends of the main pipe; a filling passage and an ejector pin are arranged on the filling head; the filling passage is led to a main pipe filling chamber, and the ejector pin is used for opening and closing the filling passage; an energy release passage is formed in the energy release head; one end of the energy release passage is led to the main pipe filling chamber; the other end of the energy release passage is led outside the carbon dioxide mining device; the fixed pressure energy release sheet is arranged between the energy release passage of the energy release head and the main pipe filling chamber in a sealed way; a heating device is arranged in the main pipe filling chamber; and the fixed pressure energy release sheet is fractured when liquid carbon dioxide filled into the main pipe filling chamber is heated, gasified and expanded to a certain pressure by the heating device. The carbon dioxide mining device disclosed by the invention can be used instead of common detonators and explosives in mine mining; gas explosion caused by fire explosion is avoided and safety production of the mine is also achieved; and a coal body can be also pre-cracked in the gas mining process, so that the air permeability of a coal layer is effectively improved, and the gas mining efficiency of the coal layer is increased.

Cementitious composites engineered for self-healing, combining self-controlled tight crack width and extreme tensile ductility. Self-healing takes place automatically at cracked locations without external intervention. In the exemplary embodiment, fiber-reinforced cementitious composites with self-controlled tight crack width less than 50 μm and tensile ductility more than 2% are prepared. Self-healing in terms of mechanical and transport properties recovery of pre-damaged (by pre-cracking) composite is revealed in a variety of environmental exposures, include wetting and drying cycles, water permeation, and chloride submersion.

The invention discloses a novel lane forming method for mining a long wall, namely a deep stope automatic lane forming physical simulation test method which changes the traditional mode of mining the long wall through a single face and double lanes. An oriented pre-cracking top-cutting lane-reserving technique is adopted; and a return mining lane of a gate road under a primary work face is reserved and serves as one of return mining lanes of the next new work face so as to mine through a single face and a single lane. The method has the advantages of removing concentrated stress above the coal on adjacent working faces, reducing the mining ratio, improving the production efficiency and reducing the resource waste, and belongs to a novel, safe, efficient, economic and scientific mining technique. At the same time, the invention designs a deep stope automatic lane forming physical simulation test device based on the principle so as to prove the reliability of the method and ensure the authenticity and the availability of the test process.

The invention relates to the technical field of coal mine mining, in particular to a non-coal-pillar auto-roadway-forming mining method suitable for thick-seam fully mechanized top coal caving. The method includes the following steps that reinforcing and supporting are carried out on a roof and two walls of a roadway; roof cutting explosion is carried out to form a pre-cracking seam; a temporary supporting device in the roadway and a gangue blocking device are erected along a retained entry; coal caving is not performed within a preset distance to the working face end close to the entry retaining side; after the roadway is stabilized, the temporary supporting device in the roadway is removed, a goaf is closed, and the entry retaining is completed. The roof cutting explosion better facilitates collapsing of the rock stratum in the goaf, the stoping space can be well filled after the rock stratum in the seam is collapsed, a short arm beam structure is formed in the lateral direction of the entry-retaining roof, a long suspended roof formed in the goaf is avoided, and the surrounding rock stress of the gob-side entry is improved; coal caving is not performed within a certain range ofthe working face end of the entry retaining side, the filling effect of the empty area of the entry retaining side is further guaranteed, rotary sinking of basic top block bodies is effectively limited, and the influence on the entry retaining stability is greatly reduced.

The invention discloses a method for preventing gob-side entry rock burst through side-drawing filling. The method comprises the following steps: additionally arranging a bracket for supporting behind a stope face bracket; constructing, exploding and drilling holes in entry sides behind the support bracket at certain intervals, wherein shallow holes are pre-cracking holes for loosening coal, and deep holes are throwing holes for throwing loosened coal into the entry; filling a part of the entry to form a pressure relief protection zone, and forming a wedged clamping anti-burst structure through top plates and bottom plates; tunneling in a previous mining surface filling entry following the mining surface gob-side entry, supporting by using a shed, carrying out guniting on the surface of the entry behind a tunneling head, and reinforcing and preventing and extinguishing fire in partial areas by taking backfill grouting measures. A novel anti-burst technical system for performing explosion, filling, in-situ tunneling and supporting behind the mining surface is established.

The invention discloses a preparation method of a modified mesoporous silicon-aluminum material. The modified mesoporous silicon-aluminum material has a pseudo-boehmite physical structure. The anhydrous chemical formula of the material by the weight of oxides is (0-8)P2O5(0-0.1)Na2O*(20-30)SiO2*(70-80)Al2O3(0-1.0)RE2O3. The specific area is 200 to 500 m2/g, and the pore volume is 0.5 to 1.5 mL/g. The preparation method comprises the following steps: step one, adding a low-concentration aluminum source into a silicon source solution, controlling the pH in a range of 10.3 to 10.8, and carrying out stationary aging for 0.5 to 3 hours; step two, adding phosphor-aluminum gel and a high-concentration aluminum source into the previous solution according to a certain ratio, and controlling the pH in a range of 3.4 to 3.8; step three, adding a rare earth solution according to a certain ratio; step four, adjusting the pH of the previous slurry to 8.0-9.0 by an alkaline solution; step five, filtering the slurry, and washing the solids by deionized water and ammonium salt. The provided modified mesoporous silicon-aluminum material can be used as the carrier of FCC catalyst, has a proper pore volume and acidic property, and is capable of performing pre-cracking on macromolecular raw oil. RE2O3 exists in a deposited state of oxides and can prevent the metal pollution, so the provided material can improve the heavy oil cracking performance of FCC catalyst, moreover, the hydrothermal stability of FCC catalyst is good, and the coke selectivity is excellent.

The invention discloses a method for pre-cracking and softening of an igneous rock hard roof. While an upper coal seam is exploited, on the premises that the distance between upper and lower coal seams, rock stratum characteristics between the coal seams and the invasion condition of an igneous rock hard rock stratum are mastered, during exploitation of the upper coal seam, by reasonably forming drilling holes in a bottom plate of an upper working face and injecting a high-pressure acid solution, a fracture acidizing unit is used for controlling the pressure of injected acid solution, on one hand, the hard igneous rock stratum are cracked through pressure, and on the other hand, the igneous rock stratum is furthered softened through the chemical reaction function of the acid solution, so that the effect of safely and efficiently cracking and softening the hard igneous rock roof of the lower coal seam is achieved finally. According to the method, acid is injected while the upper coal seam is exploited, the structure of the hard roof of the lower coal seam is broken, and the strength of the hard roof is lowered; and possible hazards of the igneous rock hard roof to normal exploitation of the working face, staff and equipment can be reduced or even avoided during exploitation of the lower coal seam.

The invention discloses a prevention method for pressure bump of approximately-vertical super-thick coal seams. The prevention method comprises the following steps that S1, before a horizontal coal seam in each stage is exploited, rock pillars, a coal seam roof and a coal seam floor on the corresponding exploitation level are subjected to water injection and softening; S2, the rock pillars, the coal seam roof and the coal seam floor on the corresponding exploitation level are subjected to pre-cracking and bursting; and S3, the horizontal coal seam in the corresponding stage is subjected to water injection, softening, pressure relief and bursting. The rock pillars, the coal seam roof and the coal seam floor are all rock mass. By the adoption of the prevention method for pressure bump of the approximately-vertical super-thick coal seams, regional structure horizontal stress can be prevented from being transferred to the coal rock mass, the energy accumulation degree of the coal rock mass is reduced, the risk of pressure bump of the approximately-vertical super-thick coal seams is effectively lowered, and technical support and safety insurance are provided for safe and efficient production of mines under the similar conditions.

The invention discloses an underground structure crack control construction method by adding inducing joints. The method includes inducing joint design, inducing joint part steel bar binding, embedded formwork setting up, concrete pouring, outer waterproof reinforcing layer construction and inner permeable crystalline waterproof material filling. The inducing joints are arranged on a concrete structure to form pre-cracking parts, stress concentration is reduced in a releasing manner, stress is relieved, further wall crack expansion is reduced and controlled, and range of cracking and deformation is limited. Water proofing is enhanced on pre-cracking parts, waterproof effect is guaranteed, and project quality is improved. The method can be widely applied to exterior wall construction of basement concrete structures in the fields of industrial and civil buildings.

The present invention relates to a blasting method for benches in an open mining area. At least three groups of holes, namely, pre-splitting holes, main blast holes and blast holes, are drilled vertically downward on a bench flat plate. Interval charging is carried out in the blast holes, and the explosive load is increased from top to bottom according to the need; interval charging is further carried in the pre-splitting holes, and the explosive load is decreased from top to bottom; and the main blast holes are fully charged. The pre-splitting holes are initiated first, the main blast holes and the blast holes are initiated after the pre-splitting holes are initiated for 50-120ms, and the interval time between the main blast holes and the blast holes is [delta]t in sequence. The effect that an idea bench slope is directly blasted out is achieved. According to the blasting method for the benches in the open mining area, vertical drilling is adopted, the construction is relatively simple, and the requirements on a drilling rig are not high; the charging procedure adopts interval charging, the blasting effect in each section can be effectively used to form an ideal bench slope angle,and the amount of rock stripping is reduced; and in terms of blasting time, the pre-cracking holes are initiated first to form a pre-splitting surface, differential blasting is used for remaining blast hole rows and between holes, and the best blasting effect is achieved by rational use of explosive energy rationally.

The invention discloses an energy absorption anchor rod tray which comprises a double-layer disk-type tray body capable of moving along an anchor rod and a pre-tightening nut which is in threaded connection to the exposed end of the anchor rod, wherein a hollow disk-type guide slot is formed between an upper-layer disk-type tray and a lower-layer disk-type tray of the double-layer disk-type tray body through an interlayer gasket; an energy absorption pipe sleeving the anchor rod is arranged between the pre-tightening nut and the double-layer disk-type tray body and consists of a tear energy absorption section and a tear pre-tightening section; the lower part of the tear pre-tightening section penetrates through a central hole of the upper-layer disk-type tray and then presses an energy absorption pipe alignment table around a central hole of the lower-layer disk-type tray through a chamfer; pre-cracked line slots are formed in the chamfer in a spacing manner; cracking supporting knives corresponding to the pre-cracked line slots are arranged at the outer edge of the energy absorption pipe alignment table. Under an impact load, the energy absorption tray can realize continuous and stable yielding energy absorption through shaft cracking yielding of the energy absorption pipe; when matched with the high-strength anchor rod, the energy absorption tray can effectively support and protect surrounding rock with high impact trend.

The invention discloses a method for preventing and treating impact mine pressure through high-dipping super-high-seam mining roadway combined pressure relief. By implementing blasting pressure reliefon a roadway side and bottom corners, the stress concentration degree of a coal body around a roadway is decreased; and by implementing deep-hole blasting pre-cracking on a roof and floor rock stratum, a roof and floor can be collapsed in time along with working face coal caving, thus large-area roof and floor rock stratum suspension is prevented from being formed, the stress concentration degreeof roadway surrounding rock is decreased, meanwhile, strong vibration disturbance generated by sudden breaking of the roof and floor rock stratum is eliminated, and the risk that vibration induces the high-stress coal body around the roadway to generate the impact mine pressure dynamic disaster is reduced.

The invention provides a gas-liquid combination directional cracking device and a method thereof. The gas-liquid combination directional cracking device is arranged in a borehole, comprising a CO2 phase change generator and a hole packer, wherein the CO2 phase change generator is of a cylinder structure, and with liquid CO2 stored inside, a first end of the generator is provided with a plurality of nozzles, and a second end is connected with the hole packer; the hole packer is of an elastic capsule structure, arranged in the back end of the CO2 phase change generator and connected with a high-pressure water pipe; the hole packer expands with water injection and is used to pack the borehole. At first, the gas-liquid combination directional cracking device arranged in the borehole performs CO2 phase change cracking in the borehole, in order to instantly release the gas in the CO2 phase change generator into the borehole to directionally pre-crack the inner wall of the borehole, and thenperforms hydraulic cracking to the borehole to allow the hydraulic crack to continuously expand, thereby forming a wide range of hydraulic crack zone in the coal and rock mass, and achieving governance of the hard roof, top coal and percussive ground pressure in a coal mine; at the same time, the permeability of a coal seam is improved, which is beneficial to coal seam permeability improvement andoutburst elimination.

The invention relates to a blasting excavation layered control method for a nuclear power engineering foundation. The blasting excavation layered control method comprises the following steps of: determining an excavation layer number and excavation depth according to foundation negative excavation depth H; determining the site attenuation rule by carrying out blasting vibration test; preliminarily determining rock mass damage depth by carrying out acoustic wave test; calculating rock mass point vibration speed and rock blasting damage depth by carrying out finite element numerical simulation; separately establishing the changing rule of mass-point peak vibration speed along with the rock blasting damage depth at positions with difference distances from a blasting source under a step blasting way and a pre-cracking blasting way; determining layered blasting excavation control standards of three distances under different blasting ways according to blasting excavation allowable damage depth of each layer; and guiding blasting design by combining the site attenuation rule to invert maximum-section dose. The blasting excavation layered control method effectively solves the problem that a three-layer excavation way of an existing method is difficult in effectively controlling damage depth and the defects that existing control standards are single, are inconvenient to use, are not suitable for the pre-cracking blasting way, and the like, so that construction progress is quickened, and relatively good economic benefits are generated.