CONSTRUCTION METHOD FOR CONTINUOUS MINING MACHINE HAVING DEVICE CONTINUOUSLY PROVIDING PROVISIONAL ROOF SUPPORT

Abstract

A method for operating a continuous mining machine having a device continuously providing provisional roof support, wherein the mining machine a rolling roof-protection portion which is fixed on a main machine frame of the continuous mining machine via a front column structure and a rear column structure. While the machine is cutting, the roof-protection device performs continuous load holding on a roof, and after cutting, performs support operations, thereby achieving simultaneous performance of cutting and support operations, and improving tunneling efficiency. Different support strengths are configured according to the hardness, completeness, and quality indicators of rock on a mine roof, such that the device is able to effectively support the roof.

Description

TECHNICAL FIELD

The present invention relates to continuous mining machines, particularly to a construction method for a continuous mining machine with a continuous temporary roof protection device.

BACKGROUND ART

Mining and driving are two crucial links in the coal mine production system engineering. Bolt supporting is a supporting method widely applied in coal mine roadways in China owing to its advantages, such as high safety, high flexibility and high efficiency, etc. With the continuous improvement of mechanization, automation and intelligence, the efficiency of fully mechanized coal mining is gradually improved. In contrast, owing to the influence of the present supporting techniques, the improvement of driving speed is very low, resulting in imbalance between mining and driving in coal production. Under the condition of existing bolt support techniques, it is of great significance to improve the driving speed to mitigate the contradiction in mining and driving succession and improve the overall production efficiency of the mines.

Boom-type roadheader with single roof bolter and continuous mining machine with roof bolting jumbo are two most common tunneling supporting techniques. Under the driving supporting condition of traditional boom-type roadheader with single roof bolter, the roadheader has to be stopped and retreated after cutting to certain footage, so that the single roof bolter can enter the working face to carry out supporting operation; under the driving condition of continuous mining machine with roof bolting jumbo, the continuous mining machine has to be withdrawn or moved to another roadway after cutting to certain footage, so that the roof bolting jumbo can enter the working face to carry out supporting operation. An important feature of the above-mentioned two supporting techniques is that the bolt supporting operation is carried out in front of the cutting equipment. Consequently the cutting operation and the bolt supporting operation can't be carried out in parallel. The alternating execution of cutting operation and bolt supporting operation results in a low operation rate of the equipment, and seriously restricts the improvement of the overall driving efficiency. Carrying out effective temporary supporting for the roof after cutting and performing bolt supporting behind of the cutting equipment are important prerequisites for realizing parallel operation of cutting and supporting and thereby improving driving efficiency.

Contents of the Invention

The object of the present invention is to provide a construction method for a continuous mining machine with a continuous temporary roof protection device, so as to solve the problem that the bolt supporting operation and the cutting operation can't be carried out in parallel because the bolt supporting operation has to be carried out in front of the driving equipment and consequently the driving efficiency is compromised.

In order to attain the technical object described above, the present invention employs the following technical solution:

A method construction for a continuous mining machine with a continuous temporary roof protection device comprises a continuous mining machine, wherein the continuous mining machine comprises a main machine part, a loading device, a horizontal-shaft cutting drum, a conveying device and a crawler travel device, wherein the horizontal-shaft cutting drum is hinged to the front portion of the main machine part, the front portion of the conveying device is connected to the loading device and the conveying device is fixedly connected to the main machine part, and the crawler travel device employs hydraulic driving and is fixed to the bottom of the main machine part, wherein the continuous mining machine further comprises a continuous temporary roof protection device, the loading device and the horizontal-shaft cutting drum are disposed in front of the continuous temporary roof protection device, and the continuous temporary roof protection device comprises a rolling roof protection part fixed to the main machine part of the continuous mining machine via a front pillar structure and a rear pillar structure;

the rolling roof protection part comprises a frame body, a closed crawler track loop, a first roller, a second roller and elastic load bearing structures, wherein the first roller and the second roller are respectively hinged to two ends of the frame body, the closed crawler track loop is wound on the first roller and the second roller and is in a rolling connection with the first roller and the second roller, a plurality of guide sleeves are fixed inside the frame body, the guide sleeves are connected with the elastic load bearing structures, and the elastic load bearing structures are in a rolling connection with the closed crawler track loop;
the front pillar structure comprises a front square inner sleeve, a front square outer sleeve and a front height-adjusting oil cylinder, wherein the bottom of the front square outer sleeve is fixed to the main machine part of the continuous mining machine by bolts, the front square inner sleeve is embedded in the front square outer sleeve, the bottom of the cylinder body of the front height-adjusting oil cylinder is hinged to the front square outer sleeve, a piston rod of the front height-adjusting oil cylinder is hinged to the front square inner sleeve, and the top end of the front square inner sleeve is hinged to the frame body; the rear pillar structure comprises a rear square inner sleeve, a rear square outer sleeve and a rear height-adjusting oil cylinder, wherein the bottom of the rear square outer sleeve is fixed to the main machine part of the continuous mining machine by bolts, the rear square inner sleeve is embedded in the rear square outer sleeve, the bottom of the cylinder body of the rear height-adjusting oil cylinder is hinged to the rear square outer sleeve, a piston rod of the rear height-adjusting oil cylinder is hinged to the rear square inner sleeve, and a waist-shaped hole structure at the top end of the rear square inner sleeve is slidably and rotatably connected with the frame body via a pin shaft;
an oil inlet bypass of a rodless cavity of the front height-adjusting oil cylinder and an oil inlet bypass of a rodless cavity of the rear height-adjusting oil cylinder are connected with an accumulator respectively, two oil inlets of the front height-adjusting oil cylinder are connected with a reversing valve via a hydraulic lock, two oil inlets of the rear height-adjusting oil cylinder are connected with the reversing valve via another hydraulic lock, and a pressure gauge and an overflow valve are provided between the reversing valve and the hydraulic locks;
the horizontal-shaft cutting drum is adjustable in length and its maximum length is the same as the width WO of the roadway to be constructed, and the total width of the loading device is smaller than the width WO of the roadway to be constructed; the construction method comprises the following steps:

• • a. classifying the roof strata of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses” according to the geological conditions of the region where the roadway is to be constructed, wherein the continuous mining machine is suitable for constructing roadways with Class I, Class II or Class III roof strata;
  • b. qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”, and determining the supporting strength Pr of the continuous temporary roof protection device according to the result of qualitative classification and a quality index of the rock mass;
  • c. calculating the pressure Pc on the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder with the following formula, according to the supporting strength Pr determined in the step b:

$\begin{array}{cc}{P}_c=\frac{P_r\times \mathrm{WO}\times L}{4\times 3.14\times R^2};& \left(1\right)\end{array}$

• •  wherein R is the cylinder diameter of the front height-adjusting oil cylinder or the rear height-adjusting oil cylinder, L is the length of contact surface between the rolling roof protection part and the roof, and WO is the width of the roadway to be constructed;
  • d. setting the pressure on the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder according to the pressure result calculated in the step c, i.e., adjusting the overflow pressure value of the overflow valve to the pressure value calculated in the step c with the aid of the pressure gauge;
  • e. manipulating the handle of the reversing valve to supply oil to the accumulator, the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder while observing the pressure indicated by the pressure gauge, and holding the pressure for 3 s when the pressure indicated by the pressure gauge can't increase anymore;
  • f determining the cutting footage of the continuous mining machine according to the array pitch of the roof bolts in a predefined scheme to set the distance of the cutting footage in each cycle to be equal to the array pitch of the roof bolts in the predefined scheme, operating the horizontal-shaft cutting drum of the continuous mining machine to cut the coal according to the distance of the cutting footage in each cycle, shoveling the coal and rock cut by the horizontal-shaft cutting drum with the loading device, and conveying the coal and rock with the conveying device to the rear part and then conveying the coal and rock away;
  • g. advancing the continuous mining machine forward by a distance corresponding to the cutting footage by means of the crawler travel device after the coal cutting, while the rolling roof protection part of the continuous temporary roof protection device persistently supports the roof of the constructed roadway;
  • h. operating the continuous mining machine to carry out the next cycle of coal cutting after the advancing, while the workers use a roof bolter to support the roof with rock bolts behind the continuous mining machine;
  • i. executing the step b again after cutting to a preset distance, i.e., determining the supporting strength Pr of the continuous temporary roof protection device again according to the conditions of the roof rock mass of the roadway to be constructed, and operating the continuous mining machine to do the construction work forward in a preset roadway direction, till the roadway driving work is completed.

As a further improved technical solution of the present invention, the total width of the loading device is smaller than the width WO of the roadway to be constructed by 200 mm.

As a further improved technical solution of the present invention, the step b comprises: qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”;

determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.02 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff rock and the rock mass is integral, and the quality index BQ of the rock mass is BQ>550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.05 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally integral, or the rock is generally stiff and the rock mass is integral, and the quality index BQ of the rock mass is 451 to 550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.1 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally fractured, or the rock is generally stiff and the rock mass is generally integral, or the rock is generally soft and the rock mass is integral, and the quality index BQ of the rock mass is 351 to 450. As a further improved technical solution of the present invention, the preset distance in the step i is 50 m.

As a further improved technical solution of the present invention, the elastic load bearing structure comprises a load bearing roller, a fork frame and a butterfly spring set, wherein the load bearing roller is in a rolling connection with the closed crawler track loop and is hinged to the fork frame, a limiting sleeve is provided at the lower part of the fork frame, a central cylinder is provided at the central part of the limiting sleeve, the limiting sleeve of the fork frame is sleeved outside the guide sleeve and the fork frame is in contact with the butterfly spring set, the central cylinder of the fork frame is inserted into a central hole of the butterfly spring set and the butterfly spring set is placed inside the guide sleeve, and the closed crawler track loop is the component in contact with the roof of the roadway.

As a further improved technical solution of the present invention, the closed crawler track loop is formed by a plurality of crawler tracks hinged together, each of which comprises a track shoe substrate, hard rubber and a chain track, wherein the hard rubber is fixed on the track shoe substrate, the chain track is connected with the track shoe substrate, and adjacent crawler tracks are hinged with each other via the chain track.

As a further improved technical solution of the present invention, the hard rubber is bonded to the track shoe substrate by means of epoxy resin and fixed to the track shoe substrate by hex screws.

As a further improved technical solution of the present invention, the rolling roof protection part comprises a tensioning mechanism, which is configured to push the first roller so as to tension up the closed crawler track loop.

As a further improved technical solution of the present invention, two continuous temporary roof protection devices are provided.

The present invention attains the following beneficial effects:

• (1) With the construction method provided by the present invention, the continuous temporary roof protection device can persistently protect and support the roof while the continuous mining machine is cutting. Therefore, it is unnecessary to stop and retreat the continuous mining machine to enable the roof bolter to reach to the front. The continuous temporary roof protection device can effectively support the roof temporarily after the cutting, and the bolt supporting operation is carried out behind the cutting equipment. Thus, parallel operation of cutting and supporting is realized, and the driving efficiency is improved. In the construction method used in the present invention, different supporting strengths are set according to the stiffness, integrity and quality index of the roof rock mass, so that the continuous temporary roof protection device can effectively support the roof, and the problem that the bolt supporting operation of the roof bolter can't be carried out effectively owing to inadequate supporting strength is prevented.
• (2) With the construction method provided by the present invention, the rolling roof protection part can persistently support the exposed roof after the continuous mining machine carries out the cutting operation, thus roof damages caused by repeated loading and unloading of the roof during the displacement of the continuous mining machine can be prevented; since the bolt supporting operation can be carried out behind the continuous mining machine, it is possible to realize parallel operation of cutting and supporting; thus the driving efficiency is improved and the impact of bolt supporting on the cutting operation is reduced.
• (3) The closed crawler track loop in the present invention is in rolling contact with the elastic load bearing structures, the first roller and the second roller. In the case that the roadway roof is not flat, the butterfly spring sets of the elastic load bearing structures have different compression amounts, so that the closed crawler track loop is in good contact with the non-flat roadway roof, achieving large area of contact with the roadway roof and high safety.
• (4) In the present invention, pressure oil can be supplied to the rodless cavity of the front height-adjusting oil cylinder and the rodless cavity of the rear height-adjusting oil cylinder via the reversing valve, the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder drive the rolling roof protection part to bear the roof; when the reversing valve doesn't introduce pressure oil into the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder, the pressure oil in the accumulator maintains the front height-adjusting oil cylinder and rear height-adjusting oil cylinder in a loaded state, thus persistent load protection for the roof is ensured with the rolling roof protection part, the efficiency is improved, and the labor intensity is deceased.

DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of the continuous mining machine in the present invention in a working state in roadway driving;

FIG. 2 is a top view of the continuous mining machine in the present invention;

FIG. 3 is an oblique view of the continuous mining machine in the present invention;

FIG. 4 is a schematic structural diagram of the continuous temporary roof protection device in the present invention;

FIG. 5 is a schematic structural diagram of the rolling roof protection part in the present invention;

FIG. 6 is a partial sectional view of the rolling roof protection part in the present invention;

FIG. 7 is a schematic structural diagram of the fork frame in the present invention;

FIG. 8 is a schematic structural diagram of the crawler track in the present invention;

FIG. 9 is a schematic structural diagram of the front pillar structure in the present invention;

FIG. 10 is a schematic structural diagram of the rear pillar structure in the present invention;

FIG. 11 is a schematic diagram of the hydraulic principle in the present invention.

EMBODIMENTS

Hereunder a specific embodiment of the present invention will be further described with reference to FIGS. 1-11.

The embodiment is intended to provide a construction method for a continuous mining machine with a continuous temporary roof protection device, so as to solve the problem that the bolt supporting operation and the cutting operation can't be carried out in parallel because the bolt supporting operation has to be carried out in front of the driving equipment and consequently the driving efficiency is compromised. Specifically: Please see FIG. 1. The reference numbers in FIG. 1 are as follows: 1—roadway floor, 2—driving face, 3—unsupported roadway roof after cutting, 4—supported roadway roof, 5—roof bolt, 6—continuous mining machine.

A construction method for a continuous mining machine 6 with a continuous temporary roof protection device is provided, comprising a continuous mining machine 6. FIG. 2 is a top view of the continuous mining machine 6. As shown in FIGS. 2 and 3, the continuous mining machine 6 comprises a main machine part, a loading device 61, a horizontal-shaft cutting drum 62, a conveying device 63 and a crawler travel device 64; the horizontal-shaft cutting drum 62 is hinged to the front portion of the main frame of the main machine part, the front portion of the conveying device 63 is connected to the loading device 61 and the conveying device 63 is fixedly connected to the main frame of the main machine part, and the crawler travel device 64 employs hydraulic driving and is fixed to the bottom of the main machine part; the main machine part comprises a main frame, a hydraulic system, and an electric control system, etc., wherein the hydraulic system and the electric control system are fixed on the main frame and configured to drive the continuous mining machine to work. All of the specific structures employ the driving structures of existing continuous mining machines. The continuous mining machine 6 further comprises a continuous temporary roof protection device, the loading device 61 and the horizontal-shaft cutting drum 62 are disposed in front of the continuous temporary roof protection device, and the continuous temporary roof protection device comprises a rolling roof protection part A fixed to the main frame of the main machine part of the continuous mining machine 6 via a front pillar structure B and a rear pillar structure C; when the horizontal-shaft cutting drum 62 carries out cutting operation, the continuous temporary roof protection device can persistently protect and support the roof so as to realize effective temporary supporting for the exposed roof after the cutting; the bolt supporting operation is carried out behind the cutting equipment, so that it is unnecessary to stop or retreat the tunneling equipment to enable the roof bolter to reach to the front; thus, parallel operation of cutting and supporting is realized, and the driving efficiency is further improved.

As shown in FIGS. 4 and 5, the rolling roof protection part A comprises a frame body A2, a closed crawler track loop A3, a first roller A10, a second roller A1, and an elastic load bearing structures, wherein the first roller A10 and the second roller A1 are respectively hinged to two ends of the frame body A2 and can rotate with respect to the frame body A2; the closed crawler track loop A3 is wound on the first roller A10 and the second roller A1, and is in a rolling connection with the first roller A10 and the second roller A1; as shown in FIG. 6, a plurality of guide sleeves A8 are fixed inside the frame body A2 (the frame body A2 includes an elongated hollow shell and triangle-like brackets for connecting with the front pillar structure B and the rear pillar structure C, the left end and the right end of the elongated hollow shell are hinged with the first roller A10 and the second roller A1 respectively, the top of the elongated hollow shell is open, the guide sleeves A8 are fixed on the inner bottom of the elongated hollow shell, and the triangle-like brackets are fixed on the front side wall and rear side wall of the elongated hollow shell for connecting with the front pillar structure B and the rear pillar structure C; the specific structure is shown in FIG. 4); the guide sleeves A8 are connected with the elastic load bearing structures, and the elastic load bearing structures are in a rolling connection with the closed crawler track loop A3; that is to say, the closed crawler track loop A3 is in rolling contact with the elastic load bearing structures, the first roller A10 and the second roller A1. The first roller A10 and the second roller A1 of the rolling roof protection part A can rotate freely; when the continuous mining machine is displaced forward or backward, the closed crawler track loop A3 rolls along the roof in a loaded state, thus continuous temporary supporting for the roof is realized.

As shown in FIG. 9, the front pillar structure B comprises a front square inner sleeve B1, a front square outer sleeve B2 and a front height-adjusting oil cylinder B3, wherein the bottom of the front square outer sleeve B2 is fixed to the main frame of the main machine part of the continuous mining machine 6 by bolts; one end of the front square inner sleeve B1 is embedded in the front square outer sleeve B2 and the front square inner sleeve B1 can slide inside the front square outer sleeve B2; the bottom of the cylinder body of the front height-adjusting oil cylinder B3 is hinged to the front square outer sleeve B2 via a pin shaft, the top of the cylinder body of the front height-adjusting oil cylinder B3 extends into the front square inner sleeve B1, the piston rod of the front height-adjusting oil cylinder B3 is hinged to the front square inner sleeve B1 via a pin shaft, and the top end of the front square inner sleeve B1 is hinged to the frame body A2 via a pin shaft; the form of hinging is shown in FIG. 4; the front height-adjusting oil cylinder B3 is a double-acting oil cylinder, the rodless cavity of the lower oil port of the front height-adjusting oil cylinder B3 extends out of the bottom of the front square outer sleeve B1 through a pipeline and is connected with pressure oil, and the rod cavity of the upper oil port of the front height-adjusting oil cylinder B3 extends out of the bottom of the front square inner sleeve B2 and the bottom of the front square outer sleeve B1 sequentially through a pipeline and is connected with pressure oil.

As shown in FIG. 10, the rear pillar structure C comprises a rear square inner sleeve C1, a rear square outer sleeve C2 and a rear height-adjusting oil cylinder C3, wherein the bottom of the rear square outer sleeve C2 is fixed to the main frame of the main machine part of the continuous mining machine 6 by bolts; one end of the rear square inner sleeve C1 is embedded in the rear square outer sleeve C2 and the rear square inner sleeve C1 can slide inside the rear square outer sleeve C2; the bottom of the cylinder body of the rear height-adjusting oil cylinder C3 is hinged to the rear square outer sleeve C2 via a pin shaft, the top of the cylinder body of the rear height-adjusting oil cylinder C3 extends into the rear square inner sleeve C1 and the piston rod of the rear height-adjusting oil cylinder C3 is hinged to the rear square inner sleeve C1 via a pin shaft, and a waist-shaped hole structure C11 at the top end of the rear square inner sleeve C1 is connected to the frame body A2 via a pin shaft in a slidable and rotatable manner; the rear height-adjusting oil cylinder C3 is a double-acting oil cylinder, and the waist-shaped hole structure C11 provides a certain reserved space for absorbing the deviation. Thus, in the case that the roof is not flat in the front-rear direction, the rolling roof protection part A can tilt to an angle in the front-rear direction, without damaging the front and rear pillar structures.

As shown in FIG. 11, an oil inlet bypass of a rodless cavity of the front height-adjusting oil cylinder B3 and an oil inlet bypass of a rodless cavity of the rear height-adjusting oil cylinder C3 are connected with an accumulator B6 respectively, two oil inlets of the front height-adjusting oil cylinder B3 are connected with a reversing valve B4 via a hydraulic lock B5, two oil inlets of the rear height-adjusting oil cylinder C3 are connected with the reversing valve B4 via another hydraulic lock B5; pressure oil can be supplied to the rodless cavity or rod cavity of the front height-adjusting oil cylinder B3 as well as the rodless cavity or rod cavity of the rear height-adjusting oil cylinder C3 via the reversing valve B4, so as to realize the loading or unloading of the front height-adjusting oil cylinder B3 and the rear height-adjusting oil cylinder C3; when the reversing valve B4 does not supply pressure oil to the front height-adjusting oil cylinder B3 and the rear height-adjusting oil cylinder C3, the pressure oil in the accumulator B6 maintains the front height-adjusting oil cylinder B3 and the rear height-adjusting oil cylinder C3 in a loaded state, thus persistent load protection of the roof is ensured with the rolling roof protection part A. A pressure gauge B7 and an overflow valve B8 are arranged between the reversing valve B4 and the hydraulic locks B5. The overflow pressure of the overflow valve B8 may be adjusted with the aid of the pressure gauge B7 to achieve different supporting strengths.

In this embodiment, two continuous temporary roof protection devices are provided. Therefore, there are two front height-adjusting oil cylinders B3 and two rear height-adjusting oil cylinders C3.

The horizontal-shaft cutting drum 62 is adjustable in length and its maximum length is the same as the width WO of the roadway to be constructed, and the total width of the loading device 61 is smaller than the width WO of the roadway to be constructed by 200 mm.

The construction method comprises the following steps:

• a. classifying the roof strata of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses” according to the geological conditions of the region where the roadway is to be constructed, wherein the continuous mining machine 6 is suitable for constructing roadways with Class I, Class II or Class III roof strata;
• b. qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”, and determining the supporting strength Pr of the continuous temporary roof protection device according to the result of qualitative classification and a quality index of the rock mass;
• c. calculating the pressure Pc on the front height-adjusting oil cylinder B3 and the rear height-adjusting oil cylinder C3 with the following formula (1), according to the supporting strength Pr determined in the step b:

$\begin{array}{cc}{P}_c=\frac{P_r\times \mathrm{WO}\times L}{4\times 3.14\times R^2};& \left(1\right)\end{array}$

• • wherein R is the cylinder diameter of the front height-adjusting oil cylinder B3 or the rear height-adjusting oil cylinder C3, L is the length of contact surface between the rolling roof protection part A and the roof, and WO is the width of the roadway to be constructed;
• d. setting the pressure on the front height-adjusting oil cylinder B3 and the rear height-adjusting oil cylinder C3 according to the pressure result calculated in the step c, i.e., adjusting the overflow pressure value of the overflow valve B8 to the pressure value calculated in the step c with the aid of the pressure gauge B7;
• e. manipulating the handle of the reversing valve B4 to supply oil to the accumulator B6, the front height-adjusting oil cylinder B3 and the rear height-adjusting oil cylinder C3 while observing the pressure indicated by the pressure gauge B7, and holding the pressure for 3 s when the pressure indicated by the pressure gauge B7 can't increase anymore;
• f. determining the cutting footage of the continuous mining machine 6 according to the array pitch of the roof bolts in a predefined scheme to set the distance of the cutting footage in each cycle to be equal to the array pitch of the roof bolts in the predefined scheme, operating the horizontal-shaft cutting drum 62 of the continuous mining machine 6 to cut the coal according to the distance of the cutting footage in each cycle, shoveling the coal and rock cut by the horizontal-shaft cutting drum 62 with the loading device 61, and conveying the coal and rock with the conveying device 63 to the rear part and then conveying the coal and rock away;
• g. advancing the continuous mining machine 6 forward by a distance corresponding to the distance of the cutting footage by means of the crawler travel device 64 after the coal cutting, while the rolling roof protection part A of the continuous temporary roof protection device persistently supports the roof of the constructed roadway;
• h. operating the continuous mining machine 6 to carry out the next cycle of coal cutting after the advancing, while the workers use a roof bolter to support the roof with rock bolts behind the continuous mining machine 6; thus, simultaneous operation of coal cutting and supporting is realized, and the roadway driving speed is greatly improved;
• i. executing the step b again after cutting to a preset distance, i.e., determining the supporting strength Pr of the continuous temporary roof protection device again according to the conditions of the roof rock mass of the roadway to be constructed, and operating the continuous mining machine 6 to do the construction work forward in a preset roadway direction, till the roadway driving work is completed. In the step i, the preset distance is 50 m.

In this embodiment, the step b comprises:

• (1) qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”;
• (2) determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.02 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff rock and the rock mass is integral, and the quality index BQ of the rock mass is BQ>550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.05 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally integral, or the rock is generally stiff and the rock mass is integral, and the quality index BQ of the rock mass is 451 to 550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.1 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally fractured, or the rock is generally stiff and the rock mass is generally integral, or the rock is generally soft and the rock mass is integral, and the quality index BQ of the rock mass is 351 to 450.

In this embodiment, the continuous mining machine 6 is provided with a continuous temporary roof protection device, which can persistently protect and support the roof while the continuous mining machine carries out the cutting operation. Therefore, it is unnecessary to stop and retreat the continuous mining machine 6 to enable the roof bolter to reach to its front. The continuous temporary roof protection device can effectively support the roof temporarily after the cutting operation, and the bolt supporting operation is carried out behind the cutting equipment. All of those features are important prerequisites for realizing parallel operation of cutting and supporting and thereby further improving the driving efficiency. In the construction method used in this embodiment, different supporting strengths are set according to the stiffness, integrity and quality index of the roof rock mass, so that the continuous temporary roof protection device can effectively support the roof, and the problem that the bolt supporting operation of the roof bolter can't be carried out effectively owing to inadequate supporting strength is prevented.

In this embodiment, as shown in FIG. 6, the elastic load bearing structure comprises a load bearing roller A6, a fork frame A5 and a butterfly spring set A7, wherein the load bearing roller A6 is in a rolling connection with the closed crawler track loop A3 through the top of an elongated hollow shell of the frame body A2 and is hinged to the fork frame A5, and can rotate freely; as shown in FIG. 7, a limiting sleeve A11 is provided at the lower part of the fork frame A5, a central cylinder A12 is provided at the central part of the limiting sleeve A11, the limiting sleeve A11 of the fork frame A5 is sleeved outside the guide sleeve A8 and the fork frame A5 is in contact with the butterfly spring set A7, the central cylinder A12 of the fork frame A5 is inserted into a central hole of the butterfly spring set A7 and the butterfly spring set A7 is placed inside the guide sleeve A8, and the closed crawler track loop A3 is the component in contact with the roof of the roadway. The closed crawler track loop A3 is in rolling contact with the elastic load bearing structures, the first roller A10 and the second roller A1. In the case that the roadway roof is not flat, the butterfly spring sets A7 of the plurality of elastic load bearing structures have different compression amounts, thereby the closed crawler track loop A3 can be in good contact with the non-flat roadway roof.

In this embodiment, the closed crawler track loop A3 is formed by a plurality of crawler tracks A4 hinged together, as shown in FIG. 8, each of which comprises a track shoe substrate A13, hard rubber A14 and a chain track A16, wherein the hard rubber A14 is fixed on the track shoe substrate A13, the chain track A16 is connected with the track shoe substrate A13, and adjacent crawler tracks A4 are hinged with each other via the chain track A16.

In this embodiment, as shown in FIG. 8, the hard rubber A14 is bonded to the track shoe substrate A13 by means of epoxy resin and fixed to the track shoe substrate A13 by hex screws A15.

In this embodiment, as shown in FIG. 6, the rolling roof protection part A comprises a tensioning mechanism A9, which may be a tensioner commonly used in the prior art, the tensioning mechanism A9 is arranged in the elongated hollow shell of the frame body A2 and configured to push the first roller A10 so as to tension up the closed crawler track loop A3. The first roller A10 is connected to an end of the frame body A2 in a 360-degree rotatable manner, and the first roller A10 is connected with an end of the frame body A2 in a horizontally slidable manner and has a certain horizontal sliding space, thus providing a tensioning stroke for the tensioning mechanism A9.

In the operation of this embodiment, firstly, the front height-adjusting oil cylinder B3 drives the front square inner sleeve B1 under the action of pressure oil, the front square inner sleeve B1 pushes the frame body A2 in the rolling roof protection part A, and the front square inner sleeve B1 is hinged to the frame body A2; the rear height-adjusting oil cylinder C3 drives the rear square inner sleeve C1 under the action of pressure oil, the rear square inner sleeve C1 pushes the frame body A2 in the rolling roof protection part A, and the rear square inner sleeve C1 is connected with the frame body A2 in a horizontally slidable and rotatable manner. The first roller A10 and the second roller A1 hinged to the frame body A2 drive the closed crawler track loop A3 to roll along the roadway roof, as a result of the travel of the continuous mining machine 6; the closed crawler track loop A3 is in rolling contact with the elastic load bearing structures, the first roller A10 and the second roller A1; the butterfly spring sets A7 of the multiple elastic load bearing structures have different compression amounts, so that the closed crawler track loop A3 is in good contact with the non-flat roadway roof; finally, temporary supporting for the roadway roof is realized.

Claims

1-9. (canceled)

10. A method for operating a continuous mining machine with a continuous temporary roof protection device wherein the continuous mining machine comprises a main machine part, a loading device, a horizontal-shaft cutting drum, a conveying device and a crawler travel device, wherein the horizontal-shaft cutting drum is hinged to the front portion of the main machine part, the front portion of the conveying device is connected to the loading device and the conveying device is fixedly connected to the main machine part, and the crawler travel device employs hydraulic driving and is fixed to the bottom of the main machine part, wherein the continuous mining machine further comprises a continuous temporary roof protection device, the loading device and the horizontal-shaft cutting drum are disposed in front of the continuous temporary roof protection device, and the continuous temporary roof protection device comprises a rolling roof protection part fixed to the main machine part of the continuous mining machine via a front pillar structure and a rear pillar structure; a. classifying the roof strata of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses” according to the geological conditions of the region where the roadway is to be constructed, wherein the continuous mining machine is suitable for constructing roadways with Class I, Class II or Class III roof strata; b. qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”, and determining the supporting strength Pr of the continuous temporary roof protection device according to the result of qualitative classification and a quality index of the rock mass; c. calculating the pressure Pc on the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder with the following formula, according to the supporting strength Pr determined in the step b: P c = P r × WO × L 4 × 3.14 × R 2; ( 1 ) d. setting the pressure on the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder according to the pressure result calculated in the step c, i.e., adjusting the overflow pressure value of the overflow valve to the pressure value calculated in the step c with the aid of the pressure gauge; e. manipulating the handle of the reversing valve to supply oil to the accumulator, the front height-adjusting oil cylinder and the rear height-adjusting oil cylinder while observing the pressure indicated by the pressure gauge, and holding the pressure for 3 s when the pressure indicated by the pressure gauge fails to increase anymore; f. determining the cutting footage of the continuous mining machine according to the array pitch of the roof bolts in a predefined scheme to set the distance of the cutting footage in each cycle to be equal to the array pitch of the roof bolts in the predefined scheme, operating the horizontal-shaft cutting drum of the continuous mining machine to cut the coal according to the distance of the cutting footage in each cycle, shoveling the coal and rock cut by the horizontal-shaft cutting drum with the loading device, and conveying the coal and rock with the conveying device to the rear part and then conveying the coal and rock away; g. advancing the continuous mining machine forward by a distance corresponding to the cutting footage by means of the crawler travel device after the coal cutting, while the rolling roof protection part of the continuous temporary roof protection device persistently supports the roof of the constructed roadway; h. operating the continuous mining machine to carry out the next cycle of coal cutting after the advancing, while workers use a roof bolter to support the roof with rock bolts behind the continuous mining machine; i. executing the step b again after cutting to a preset distance, determining the supporting strength Pr of the continuous temporary roof protection device again according to the conditions of the roof rock mass of the roadway to be constructed, and operating the continuous mining machine to do the construction work forward in a preset roadway direction, till the roadway driving work is completed.

the rolling roof protection part comprises a frame body, a closed crawler track loop, a first roller, a second roller and an elastic load bearing structures, wherein the first roller and the second roller are respectively hinged to two ends of the frame body, the closed crawler track loop is wound on the first roller and the second roller and is in a rolling connection with the first roller and the second roller, a plurality of guide sleeves are fixed inside the frame body, the guide sleeves are connected with the elastic load bearing structures, and the elastic load bearing structures are in a rolling connection with the closed crawler track loop;

the front pillar structure comprises a front square inner sleeve, a front square outer sleeve and a front height-adjusting oil cylinder, wherein the bottom of the front square outer sleeve is fixed to the main machine part of the continuous mining machine by bolts, the front square inner sleeve is embedded in the front square outer sleeve, the bottom of the cylinder body of the front height-adjusting oil cylinder is hinged to the front square outer sleeve, a piston rod of the front height-adjusting oil cylinder is hinged to the front square inner sleeve, and the top end of the front square inner sleeve is hinged to the frame body;

the rear pillar structure comprises a rear square inner sleeve, a rear square outer sleeve and a rear height-adjusting oil cylinder, wherein the bottom of the rear square outer sleeve is fixed to the main machine part of the continuous mining machine by bolts, the rear square inner sleeve is embedded in the rear square outer sleeve, the bottom of the cylinder body of the rear height-adjusting oil cylinder is hinged to the rear square outer sleeve, a piston rod of the rear height-adjusting oil cylinder is hinged to the rear square inner sleeve, and a waist-shaped hole structure at the top end of the rear square inner sleeve is slidably and rotatably connected with the frame body via a pin shaft;

an oil inlet bypass of a rodless cavity of the front height-adjusting oil cylinder and an oil inlet bypass of a rodless cavity of the rear height-adjusting oil cylinder are connected with an accumulator respectively, two oil inlets of the front height-adjusting oil cylinder are connected with a reversing valve via a hydraulic lock, two oil inlets of the rear height-adjusting oil cylinder are connected with the reversing valve via another hydraulic lock, and a pressure gauge and an overflow valve are provided between the reversing valve and the hydraulic locks;

the horizontal-shaft cutting drum is adjustable in length and its maximum length is the same as the width WO of the roadway to be constructed, and the total width of the loading device is smaller than the width WO of the roadway to be constructed;

the construction method comprises the following steps:

wherein R is the cylinder diameter of the front height-adjusting oil cylinder or the rear height-adjusting oil cylinder, L is the length of contact surface between the rolling roof protection part and the roof, and WO is the width of the roadway to be constructed;

11. The method according to claim 10, wherein the total width of the loading device is smaller than the width WO of the roadway to be constructed by 200 mm.

12. The method according to claim 11, wherein the step b comprises:

(1) qualitatively classifying the stiffness and integrity of the roof rock mass of the roadway to be constructed as per GB/T 50218-2014 “Standard for Classification of Engineering Rock Masses”;

(2) determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.02 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff rock and the rock mass is integral, and the quality index BQ of the rock mass is BQ>550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.05 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally integral, or the rock is generally stiff and the rock mass is integral, and the quality index BQ of the rock mass is 451 to 550; determining the supporting strength Pr of the continuous temporary roof protection device to be Pr=0.1 MPa, if the result of qualitative classification of the stiffness and integrity of the roof rock mass of the roadway indicates that the rock is stiff and the rock mass is generally fractured, or the rock is generally stiff and the rock mass is generally integral, or the rock is generally soft and the rock mass is integral, and the quality index BQ of the rock mass is 351 to 450.

13. The method according to claim 10, wherein in the step i, the preset distance is 50 m.

14. The method according to claim 10, wherein the elastic load bearing structure comprises a load bearing roller, a fork frame and a butterfly spring set, wherein the load bearing roller is in a rolling connection with the closed crawler track loop and is hinged to the fork frame, a limiting sleeve is provided at the lower part of the fork frame, a central cylinder is provided at the central part of the limiting sleeve, the limiting sleeve of the fork frame is sleeved outside the guide sleeve and the fork frame is in contact with the butterfly spring set, the central cylinder of the fork frame is inserted into a central hole of the butterfly spring set and the butterfly spring set is placed inside the guide sleeve, and the closed crawler track loop is the component in contact with the roof of the roadway.

15. The method according to claim 10, wherein the closed crawler track loop is formed by a plurality of crawler tracks hinged together, each of which comprises a track shoe substrate, hard rubber and a chain track, wherein the hard rubber is fixed on the track shoe substrate, the chain track is connected with the track shoe substrate, and adjacent crawler tracks are hinged with each other via the chain track.

16. The method according to claim 15, wherein the hard rubber is bonded to the track shoe substrate by epoxy resin and fixed to the track shoe substrate by hex screws.

17. The method according to claim 10, wherein the rolling roof protection part comprises a tensioning mechanism, which is configured to push the first roller to tension up the closed crawler track loop.

18. The method according to claim 10, wherein two continuous temporary roof protection devices are provided.

19. The method according to claim 11, wherein in the step i, the preset distance is 50 m.

20. The method according to claim 11, wherein the elastic load bearing structure comprises a load bearing roller, a fork frame and a butterfly spring set, wherein the load bearing roller is in a rolling connection with the closed crawler track loop and is hinged to the fork frame, a limiting sleeve is provided at the lower part of the fork frame, a central cylinder is provided at the central part of the limiting sleeve, the limiting sleeve of the fork frame is sleeved outside the guide sleeve and the fork frame is in contact with the butterfly spring set, the central cylinder of the fork frame is inserted into a central hole of the butterfly spring set and the butterfly spring set is placed inside the guide sleeve, and the closed crawler track loop is the component in contact with the roof of the roadway.

21. The method according to claim 11, wherein the closed crawler track loop is formed by a plurality of crawler tracks hinged together, each of which comprises a track shoe substrate, hard rubber and a chain track, wherein the hard rubber is fixed on the track shoe substrate, the chain track is connected with the track shoe substrate, and adjacent crawler tracks are hinged with each other via the chain track.

22. The method according to claim 21, wherein the hard rubber is bonded to the track shoe substrate by epoxy resin and fixed to the track shoe substrate by hex screws.

23. The method according to claim 11, wherein the rolling roof protection part comprises a tensioning mechanism, which is configured to push the first roller to tension up the closed crawler track loop.

24. The method according to claim 11, wherein two continuous temporary roof protection devices are provided.

25. The method according to claim 12, wherein in the step i, the preset distance is 50 m.

26. The method according to claim 12, wherein the elastic load bearing structure comprises a load bearing roller, a fork frame and a butterfly spring set, wherein the load bearing roller is in a rolling connection with the closed crawler track loop and is hinged to the fork frame, a limiting sleeve is provided at the lower part of the fork frame, a central cylinder is provided at the central part of the limiting sleeve, the limiting sleeve of the fork frame is sleeved outside the guide sleeve and the fork frame is in contact with the butterfly spring set, the central cylinder of the fork frame is inserted into a central hole of the butterfly spring set and the butterfly spring set is placed inside the guide sleeve, and the closed crawler track loop is the component in contact with the roof of the roadway.

27. The method according to claim 12, wherein the closed crawler track loop is formed by a plurality of crawler tracks hinged together, each of which comprises a track shoe substrate, hard rubber and a chain track, wherein the hard rubber is fixed on the track shoe substrate, the chain track is connected with the track shoe substrate, and adjacent crawler tracks are hinged with each other via the chain track.

28. The method according to claim 25, wherein the hard rubber is bonded to the track shoe substrate by epoxy resin and fixed to the track shoe substrate by hex screws.

29. The method according to claim 12, wherein the rolling roof protection part comprises a tensioning mechanism, which is configured to push the first roller to tension up the closed crawler track loop.