Abstract: A method of intelligent prediction of coal stress and different diameters pressure relief based on optimization neural network collects the drilling parameters while drilling the pressure-relief boreholes at one working face and to obtain the stress values using the accompanying boreholes of the pressure-relief boreholes to construct the prediction model; in this way, the prediction model is applied to predict the value of mining stress when drilling pressure-relief borehole in other working faces; according to the prediction results, the distribution law of mining stress is analyzed, and then the reaming position, length of reaming section and hole diameter of the pressure relief borehole are determined; the present invention monitors the pressure-relief borehole construction process of accompanying borehole parameters at the same time, monitoring the adjacent accompanying borehole corresponding to the depth of the drilling borehole coal stress value.

Abstract: A self-entry exploitation device and method for marine natural gas hydrates is provided. The exploitation device includes a self-entry structural body (1), a sand control device (2) and a gas-liquid lifting system. The self-entry structural body (1) is a gravity anchor. The sand control device (2) and the gas-liquid lifting system are mounted on the self-entry structural body (1). At least one cavity (21) is formed between the self-entry structural body (1) and the sand control device (2), and the cavity (21) is communicated with at least one channel. The sand control device (2) allows liquid and gas to pass through to enter the cavity (21) and is able to filter out silt. The gas-liquid lifting system includes at least one lifting power device (31) and has an end connected to the cavity (21) and an end extending out through a pipeline.

Abstract: A method and a system for determining a supporting structure by combining a stress environment and an underground surrounding rock structure are provided in the disclosure, which relates to the technical field of stability analysis of coal-mine rock mass. The method includes: defining a stress peak position and an in-situ stress position by determining the stress environment; identifying the underground surrounding rock structure, identifying lithology and constructing a three-dimensional model of a rock stratum to analyze damage degree of the rock stratum; pretreating, namely normalizing, the damage degree of the rock stratum at two sides and comparing the damage degree of the rock stratum at a roof and the floor; and identifying the supporting structure and determining supporting effectiveness and a supporting length. The method of the disclosure is different from related art, and ensures that the supporting structure meets mechanical foundation and practical engineering requirements as a whole.

Abstract: The invention discloses a suction cylinder exploitation device and method for marine natural gas hydrates. The exploitation device comprises an exploitation cylinder, a water pump, a sand control device, a liquid-gas filling system and the like. Through the specially-designed exploitation cylinder and mating devices thereof, the exploitation cylinder can sink below a seabed surface to exploit natural gas hydrates deep below the seabed surface and can be withdrawn. A series of problems such as high well drilling and completion cost of traditional deep-sea drilling exploitation methods, and damage, collapses and sand generation of plain concrete wellbores under the effect of formation pressure are solved, and the limitations that traditional capping depressurization methods can only exploit submarine superficial hydrates and are low in exploitation efficiency are overcome.

Abstract: The present disclosure relates to a construction method for a deformable anchor cable capable of being prestressed. The anchor cable includes an outer sleeve, a shrinkage pipe, an inner sleeve, a steel strand, an anchor and a tray. When the anchor cable is in use, a hole is drilled first, then the anchor cable is mounted in the drilled hole, and finally a prestress is applied to the steel strand of the anchor cable. According to the construction method, the construction is convenient; the anchor cable has the characteristics of high strength and large deformation, and can be easily prestressed; and the large deformation is realized by squeezing the inner sleeve by means of the anchor, which completely overcomes the problem of breaking a cold-drawn rod during the large deformation process.

Abstract: The present invention relates to a support method of preset internal cable for in-situ tunnel expansion project, comprising a cable, lockset and an anchoring agent, wherein before the excavation of the newly-built tunnel, a borehole is drilled into the surrounding rock from the in-situ tunnel, and the cable is installed in the borehole and pre-stressed, so as to play a supporting role at the moment of excavation of the newly-built tunnel. The cable is fixed in the depth of the surrounding rock by the anchoring agent, and the lockset of the cable is set at the position of the excavation contour line of the newly-built tunnel inside the surrounding rock. The present invention provides a method that does not interfere with the excavation construction and can effectively support the surrounding rock of the expanded tunnel in advance.

Abstract: The present disclosure relates to a construction method for a deformable anchor cable capable of being prestressed. The anchor cable includes an outer sleeve, a shrinkage pipe, an inner sleeve, a steel strand, an anchor and a tray. When the anchor cable is in use, a hole is drilled first, then the anchor cable is mounted in the drilled hole, and finally a prestress is applied to the steel strand of the anchor cable. According to the construction method, the construction is convenient; the anchor cable has the characteristics of high strength and large deformation, and can be easily prestressed; and the large deformation is realized by squeezing the inner sleeve by means of the anchor, which completely overcomes the problem of breaking a cold-drawn rod during the large deformation process.

Abstract: A self-entry exploitation device and method for marine natural gas hydrates is provided. The exploitation device includes a self-entry structural body (1), a sand control device (2) and a gas-liquid lifting system. The self-entry structural body (1) is a gravity anchor. The sand control device (2) and the gas-liquid lifting system are mounted on the self-entry structural body (1). At least one cavity (21) is formed between the self-entry structural body (1) and the sand control device (2), and the cavity (21) is communicated with at least one channel. The sand control device (2) allows liquid and gas to pass through to enter the cavity (21) and is able to filter out silt. The gas-liquid lifting system includes at least one lifting power device (31) and has an end connected to the cavity (21) and an end extending out through a pipeline.

Abstract: The present invention relates to a support method of preset internal cable for in-situ tunnel expansion project, comprising a cable, lockset and an anchoring agent, wherein before the excavation of the newly-built tunnel, a borehole is drilled into the surrounding rock from the in-situ tunnel, and the cable is installed in the borehole and pre-stressed, so as to play a supporting role at the moment of excavation of the newly-built tunnel. The cable is fixed in the depth of the surrounding rock by the anchoring agent, and the lockset of the cable is set at the position of the excavation contour line of the newly-built tunnel inside the surrounding rock. The present invention provides a method that does not interfere with the excavation construction and can effectively support the surrounding rock of the expanded tunnel in advance.

Abstract: The invention discloses a suction cylinder exploitation device and method for marine natural gas hydrates. The exploitation device comprises an exploitation cylinder, a water pump, a sand control device, a liquid-gas filling system and the like. Through the specially-designed exploitation cylinder and mating devices thereof, the exploitation cylinder can sink below a seabed surface to exploit natural gas hydrates deep below the seabed surface and can be withdrawn. A series of problems such as high well drilling and completion cost of traditional deep-sea drilling exploitation methods, and damage, collapses and sand generation of plain concrete wellbores under the effect of formation pressure are solved, and the limitations that traditional capping depressurization methods can only exploit submarine superficial hydrates and are low in exploitation efficiency are overcome.

Abstract: Disclosed is a method for deep-sea extraction of natural gas hydrates with reservoir top control and sand prevention, belonging to the technical field of natural gas hydrates mining. A grouting layer is constructed between a natural gas hydrates reservoir layer and an upper overburden layer by adopting a multi-branch horizontal well process, a vertical shaft is drilled further into the natural gas hydrates reservoir layer after the grouting layer is stabilized, and a mining device and a bottom plugging device are installed in the vertical shaft according to a thickness of the reservoir.

Abstract: The present disclosure relates to a construction method for a deformable anchor cable capable of being prestressed. The anchor cable includes an outer sleeve, a shrinkage pipe, an inner sleeve, a steel strand, an anchor and a tray. When the anchor cable is in use, a hole is drilled first, then the anchor cable is mounted in the drilled hole, and finally a prestress is applied to the steel strand of the anchor cable. According to the construction method, the construction is convenient; the anchor cable has the characteristics of high strength and large deformation, and can be easily prestressed; and the large deformation is realized by squeezing the inner sleeve by means of the anchor, which completely overcomes the problem of breaking a cold-drawn rod during the large deformation process.

Abstract: The present invention relates to a shear test device and test method of rock mass discontinuities under constant normal stiffness condition. The device includes: a base used for placing a test piece; a loading framework fixedly connected with the base; a shear loading system used for applying a shear force to the test piece; a normal loading system used for applying a normal pressure to the test piece; a normal displacement monitoring system used for measuring the magnitude of normal displacement of the test piece in real time; and a computer control system used for receiving the data of the normal displacement of the test piece in real time, and constantly adjusting the normal pressure applied by the normal loading system to the test piece according to the principle that the normal stiffness of the test piece is unchanged.

Abstract: The present invention relates to a shear test device and test method of rock mass discontinuities under constant normal stiffness condition. The device includes: a base used for placing a test piece; a loading framework fixedly connected with the base; a shear loading system used for applying a shear force to the test piece; a normal loading system used for applying a normal pressure to the test piece; a normal displacement monitoring system used for measuring the magnitude of normal displacement of the test piece in real time; and a computer control system used for receiving the data of the normal displacement of the test piece in real time, and constantly adjusting the normal pressure applied by the normal loading system to the test piece according to the principle that the normal stiffness of the test piece is unchanged.

Abstract: The present method for testing the bonding strength of rock bolt-grout-surrounding rock comprises the following steps: step 1, fabricating the simulative body of a rock bolt provided with a first surface, wherein the concave-convex characteristic of the first surface is consistent with the surface appearance of a rock bolt, and the first surface is a plane; step 2, pouring a grout layer for simulating the grout material on the first surface of the simulative body of the rock bolt; step 3, pouring a surrounding rock layer for simulating the surrounding rock material on the solidified grout layer, wherein the simulative body of the rock bolt, the grout layer and the surrounding rock layer form a simulative anchoring body; and step 4, performing a shear test along the simulative stress direction of the simulative anchoring body to obtain mechanical parameters reflecting the bonding strength of the anchoring body.