A reverse construction method for a roadway passing under a goaf in stages

Abstract

The present invention discloses a method for reverse construction of a roadway passing under a goaf in stages. The characteristics are as follows: Firstly, excavate the surrounding rock of the straight wall part of the roadway, drive grouting anchor cables and single props. Excavate the surrounding rock of the arch part of the roadway by picking the top at the innermost side of the roadway to form a free-face working surface. Reverse-excavate the surrounding rock of the arch part of the roadway from inside to outside. Keep up with the tunneling face of the arch part, cut off the ultra-long exposed section of the original grouting anchor cable, drive new grouting anchor cables, and lift the single props to make the longitudinal and transverse I-beams closely adhere to the roof surrounding rock, realizing the coupling control of deep-shallow-surface of the roof of the roadway passing under the goaf. After the roadway is stable, remove the single props to form a complete roadway; during the tunneling process of the roadway, the roof is intact surrounding rock to ensure the stability of the roadway roof and construction safety; use the grouting anchor cables to grout the goaf on the roof to coagulate the broken surrounding rock into a whole to ensure safety during the use of the roadway.

Description

Technical Field

[0001] The present invention relates to the technical field of safety in underground engineering, and particularly relates to a method for reverse construction of a roadway passing under a goaf in stages. Background Art

[0002] Coal is a basic energy source and an important raw material, occupying a dominant position in the energy structure; in China, extremely close coal seams and extra-thick coal seams are widely distributed. Fully mining the extremely close coal seams and extra-thick coal seams can avoid waste of coal resources, increase coal production, improve coal recovery rate, and extend the service life of the mine.

[0003] Currently, for extremely close coal seams and extra-thick coal seams, after the upper-layer coal resources of the extremely close coal seams and the upper-split coal resources of the extra-thick coal seams are mined, the roof collapses to form a goaf. When mining the lower-layer coal or the lower-split coal of the extra-thick coal seam, a mining roadway is arranged. The roof of the mining roadway is the goaf. During the tunneling process of the roadway, it passes under the goaf. Due to the broken surrounding rock in the goaf, it is difficult to support the roadway, and the roof is prone to caving during the tunneling process of the roadway, resulting in serious accidents. The existing technology has the following problems:

[0004] 1. The roof of the roadway is a goaf, and the surrounding rock is broken. There is a risk of roof fall during the overall tunneling process of the roadway, and the tunneling safety of the roadway is poor;

[0005] 2. The roof of the roadway is loose and broken, and its self-bearing capacity is very weak. The support strength of conventional bolts (cables) is low, and the phenomenon of slippage occurs, resulting in poor surrounding rock control effect. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the above-mentioned existing technologies, and provide a method for reverse construction of a roadway passing under a goaf in stages.

[0007] The technical solution provided by the present invention is: a method for reverse construction of a roadway passing under a goaf in stages, which is characterized in that it includes the following steps:

[0008] a. Excavate the surrounding rock of the straight wall part of the roadway passing under the goaf, drive a working face, and closely follow the tunneling working face to support the roadway. Lay a steel mesh on the roof, drive grouting cables, use the grouting cables to grout the surrounding rock of the goaf in the roadway, erect single props, and install I-beams longitudinally and transversely at the top of the single props;

[0009] b. After the straight wall of the roadway is excavated and stabilized, reverse and gradually break the grouting cables and steel mesh from the innermost side of the roadway, excavate the surrounding rock of the arch part of the roadway, and the single props and the longitudinal and transverse I-beams at the top gradually rise following the progress of the roof excavation construction of the roadway to ensure the safety of the roof excavation construction of the roadway and form a free-face for the excavation of the arch part of the roadway;

[0010] Reinforcement meshes are laid on the vault of the roadway c. The overlong and exposed sections of the original grouted anchor cables are cut off. New grouted anchor cables are inserted between the original grouted anchor cables. The longitudinal and transverse I-beams at the top of the single props are closely attached to the roadway roof.

[0011] The surrounding rock of the roadway arch is driven in reverse from the innermost aerial working face of the roadway arch d. The longitudinal and transverse I-beams and grouted anchor cables at the top of the single props are driven closely following the driving face to form a complete roadway passing under the goaf.

[0012] Furthermore, in step a, the grouted anchor cables pass through the intact surrounding rock of the roadway arch and the broken surrounding rock of the upper goaf. The broken surrounding rock of the roof goaf is grouted using the grouted anchor cables, and a pre-tightening force is applied to the intact surrounding rock of the roadway arch. Cross-shaped clamping grooves are provided at the top of the single support. The longitudinal and transverse I-beams are connected into a whole using connecting rings to achieve the overall control of the straight wall part of the roadway.

[0013] Furthermore, in step b, the surrounding rock of the roadway arch is constructed by picking the roof from the innermost to the outermost of the roadway. The picking distance is the longitudinal spacing of the I-beams. The driving footage of the picking is 200 mm. After each driving footage of the picking is completed, the single props are raised, and the longitudinal and transverse I-beams are closely attached to the surrounding rock. Single props are added at the end of the roadway where the picking construction has not been carried out.

[0014] Furthermore, after the construction of laying the reinforcement meshes on the vault of the roadway in step c is completed, the overlong and exposed sections of the original grouted anchor cables are cut off. The exposed length of the grouted anchor cables is 0.1 - 0.35 mm. New grouted anchor cables are inserted and driven between the original grouted anchor cables. The length of the new grouted anchor cables is 2 - 3 m longer than that of the original grouted anchor cables. The roof goaf is grouted for the second time using the new grouted anchor cables, and a pre-tightening force is applied to the original grouted anchor cables and the new grouted anchor cables. The single props are raised, and the longitudinal and transverse I-beams are closely attached to the roadway roof to achieve the deep-shallow-surface coupling control of the roof of the roadway goaf.

[0015] Furthermore, after the construction of the innermost arch of the roadway in step d is completed, an aerial working face is formed. The surrounding rock of the roadway arch is driven in reverse from the inside to the outside. After each driving footage of the surrounding rock of the roadway arch is completed, the new grouted anchor cables, the original grouted anchor cables and the single props of the roadway are implemented to ensure the timely support of the I-beams at the top of the grouted anchor cables and the single props for the roadway roof, forming a complete roadway passing under the goaf. After the roadway passing under the goaf is stable, the single props and the I-beams are gradually removed to prepare for the driving of the next cycle of the roadway passing under the goaf.

[0016] The beneficial effects of the present invention are as follows: 1. The roof during the driving of the roadway is intact surrounding rock, ensuring the stability of the roadway roof and the construction safety; 2. The roof goaf is grouted using the grouted anchor cables to coagulate the broken surrounding rock into a whole, ensuring the safety during the use of the roadway. Description of the Drawings

[0017] Figure 1 is the flow chart of the present invention;

[0018] Figure 2 is the schematic diagram of the driving of the straight-wall surrounding rock of the present invention;

[0019] Figure 3 is the schematic diagram of the driving of the roof pick of the roadway of the present invention

[0020] Figure 4 is the schematic diagram of the driving of the arch surrounding rock of the present invention;

[0021] Figure 5 is the schematic diagram of the complete roadway of the present invention.

[0022] Wherein: 1 single prop, 2 original grouted cable bolt, 3 longitudinal I-beam, 4 transverse I-beam, 5 new grouted cable bolt. Detailed implementation manners

[0023] For better understanding and implementation, the present invention will be described in detail below with reference to the accompanying drawings.

[0024] As shown in Figure 1 、 2 、3, 4, 5, a method for reverse construction of a roadway under a goaf in stages includes the following steps:

[0025] First step, excavate the surrounding rock of the straight wall part of the roadway under the goaf, drive a distance of one working face, closely support the roadway following the driving operation, lay a steel mesh on the roof, drive the original grouted cable bolt 2, grout the surrounding rock of the roadway goaf by using the original grouted cable bolt 2, erect a single prop 1, and install a longitudinal I-beam 3 and a transverse I-beam 4 along the longitudinal and transverse directions of the roadway at the top of the single prop 1;

[0026] Second step, after the excavation of the straight wall of the roadway is stable, reverse and break the original grouted cable bolt 2 and the steel mesh section by section from the innermost side of the roadway, quickly excavate the surrounding rock of the arch top of the roadway, and the single prop 1 and the longitudinal I-beam 3 and the transverse I-beam 4 at the top gradually rise following the advance of the roof pick construction of the roadway to ensure the safety of the roof pick construction of the roadway and form a free face for the excavation of the arch part of the roadway;

[0027] Third step, lay a steel mesh on the arch top of the roadway, cut off the overlong exposed section of the original grouted cable bolt 2, insert and drive new grouted cable bolts 5 between the original grouted cable bolts 2, and the longitudinal I-beam 3 and the transverse I-beam 4 at the top of the single prop 1 are close to the roof of the roadway;

[0028] Fourth step, reverse and drive the surrounding rock of the arch part of the roadway from the free face of the innermost arch part of the roadway, and the longitudinal I-beam 3, the transverse I-beam 4 at the top of the single prop 1 and the new grouted cable bolt 5 are driven closely following the driving operation face to form a complete roadway under the goaf.

[0029] In the first step mentioned above, first, the surrounding rock of the straight wall part of the roadway tunneling under the goaf is excavated. The direct roof of the roadway is the intact surrounding rock of the arch part of the roadway. Grouting anchor cables 2 are driven. The grouting anchor cables 2 pass through the surrounding rock of the arch part of the roadway, and the ends of the grouting anchor cables 2 are located at the position of the upper goaf. The broken surrounding rock of the upper goaf of the roadway is grouted by using the grouting anchor cables 2. After the grout solidifies, a pre-tightening force is applied to the grouting anchor cables 2 to realize the active support for the surrounding rock of the arch part of the roadway and the surrounding rock of the upper goaf;

[0030] Single props 1 are installed in the roadway tunneling under the goaf. Cross-shaped clamping grooves are arranged at the tops of the single props 1. The longitudinal I-beams 3 and the transverse I-beams 4 are fixed by the clamping grooves, and the longitudinal I-beams 3 and the transverse I-beams 4 are connected into a whole by using connecting rings to realize the overall control of the straight wall part of the roadway.

[0031] In the second step mentioned above, after the straight wall of the roadway is stable, roof ripping construction is carried out reversely from the innermost side to the outermost side of the roadway. The distance of roof ripping construction is the longitudinal spacing of the I-beams 3. Multiple times of roof ripping construction with small footage are adopted. The footage of roof ripping is 200 mm, and the footage size can be adjusted according to the characteristics of the surrounding rock of the arch part. During the roof ripping process, the single props 1 closely follow the rising of the roof ripping to ensure that the I-beams are closely attached to the surrounding rock;

[0032] Alternatively, 2 - 4 rows of single props 1 are newly added between the single props 1 at the innermost side of the un-ripped roadway to increase the roof support strength of the un-ripped roadway and ensure the stability of the roadway during roof ripping.

[0033] In the third step mentioned above, after the roof ripping construction of the surrounding rock of the arch part at the innermost side of the roadway is completed, the overlong exposed section of the original grouting anchor cables 2 is cut off. The exposed length of the grouting anchor cables 2 is 0.1 - 0.35 mm, and new grouting anchor cables 5 are driven in an interspersed manner between the original grouting anchor cables 2. The length of the new grouting anchor cables 5 is 2 - 3 m longer than that of the original grouting anchor cables;

[0034] The roof goaf is secondarily grouted with cement slurry by using the new grouting anchor cables 5. The water-cement ratio of the cement slurry is controlled at 0.6 - 0.8. The cement slurry fills the fissured surrounding rock of the goaf to realize the full-length anchoring of the new grouting anchor cables 5 and the original grouting anchor cables 2. After the cement slurry solidifies, a pre-tightening force is applied to the original grouting anchor cables 2 and the new grouting anchor cables 5, and the pre-tightening force is controlled at 100 kN - 120 kN;

[0035] The tight single props 1 closely follow the rising of the roof-ripped surrounding rock. The longitudinal I-beams 3 and the transverse I-beams 4 are closely attached to the roof surrounding rock of the roadway to realize the strong support for the roof of the roadway tunneling under the goaf and form the deep-shallow-surface coupling control of the roof of the roadway tunneling under the goaf.

[0036] In the fourth step mentioned above, after the roof ripping construction of the surrounding rock of the arch part at the innermost side of the roadway is completed, a free face tunneling working face is formed for the surrounding rock of the arch part of the roadway. The tunneling of the surrounding rock of the arch part of the roadway is carried out reversely from the inside to the outside. Before tunneling, single props 1 are added in front of the footage of the roadway to strengthen the stability of the roof in front of the roadway;

[0037] During the tunneling process of the surrounding rock in the arch part of the roadway, as shown in the second and third steps, the support of the new grouted anchor cable 5, the original grouted anchor cable 2 and the single prop 1 is implemented on the roof of the roadway passing under the goaf, ensuring that the new grouted anchor cable 5, the original grouted anchor cable 2 and the single prop 1 timely support the roof of the roadway, and forming a complete support system for the roadway passing under the goaf;

[0038] After all the construction of the roadway passing under the goaf is completed, the forces on the single prop 1 and the grouted anchor cable tend to be stable. The single prop 1 and the I-beam are removed section by section from the inside out. During the removal process, the change in the force on the grouted anchor cable is monitored at all times. When the force value on the grouted anchor cable does not change, the single prop and the I-beam can be completely removed. However, when the force on the grouted anchor cable suddenly increases or the force application rate of the grouted anchor cable increases, the removal of the single prop and the I-beam is stopped, and the removal is carried out after the roadway is stable, preparing for the next cycle of tunneling of the roadway passing under the goaf.

[0039] As is known by common technical knowledge, the present invention can be implemented by other embodiments that do not depart from its essence or essential features. Therefore, in all aspects, it is only an example and not the only one. All changes within the scope of the present invention or within the scope equivalent to the present invention are encompassed by the present invention.

Claims

1. A method for reverse construction of a roadway passing under a goaf in stages, Characterized in that, It includes the following steps: a Excavate the surrounding rock of the straight wall part of the roadway passing under the goaf, drive one working face, closely support the roadway following the driving working face, lay a steel mesh on the roof, drive grouting anchor cables, use the grouting anchor cables to grout the surrounding rock of the roadway passing under the goaf, erect single props, and install I-beams longitudinally and transversely at the top of the single props; b After the excavation of the straight wall of the roadway is stable, reverse and gradually break the grouting anchor cables and steel meshes section by section from the innermost side of the roadway, excavate the surrounding rock of the arch part of the roadway, and the single props and the longitudinal and transverse I-beams at the top gradually rise following the advance of the roof excavation construction of the roadway to ensure the safety of the roof excavation construction of the roadway and form a free face for the excavation of the arch part of the roadway; c Lay a steel mesh on the arch roof of the roadway, cut off the overlong exposed section of the original grouting anchor cable, insert and drive new grouting anchor cables between the original grouting anchor cables, and the longitudinal and transverse I-beams at the top of the single props are closely attached to the roof of the roadway; d Drive the surrounding rock of the arch part of the roadway reversely from the free face of the innermost arch part of the roadway, and drive the longitudinal, transverse I-beams and grouting anchor cables at the top of the single props closely following the driving working face to form a complete roadway passing under the goaf.

2. The method for reverse construction of a roadway passing under a goaf in stages according to claim 1, Characterized in that, The grouting anchor cables in step a pass through the intact surrounding rock of the arch part of the roadway and the broken surrounding rock of the upper goaf, use the grouting anchor cables to grout the broken surrounding rock of the roof goaf, apply a pre-tightening force to the intact surrounding rock of the arch part of the roadway, set a cross-shaped clamping groove at the top of the single support, and use connecting rings to connect the longitudinal and transverse I-beams into a whole to realize the overall control of the straight wall part of the roadway.

3. The method for reverse construction of a roadway passing under a goaf in stages according to claim 1, Characterized in that, The surrounding rock of the arch part of the roadway in step b is excavated by picking the roof from the innermost side to the outermost side of the roadway, the picking distance is the longitudinal spacing of the I-beams, the advance of the picking is 200 mm, after each picking advance is completed, raise the single props, the longitudinal and transverse I-beams are closely attached to the surrounding rock, and add single props at the end of the roadway where the roof has not been picked.

4. The method for reverse construction of a roadway passing under a goaf in stages according to claim 1, Characterized in that, After the construction of laying the steel mesh on the arch roof in step c is completed, cut off the overlong exposed section of the original grouting anchor cable, the exposed length of the grouting anchor cable is 0.1 - 0.35 mm, and insert and drive new grouting anchor cables between the original grouting anchor cables, the length of the new grouting anchor cables is 2 - 3 m longer than the original grouting anchor cables, use the new grouting anchor cables to conduct secondary grouting on the roof goaf, apply a pre-tightening force to the original grouting anchor cables and the new grouting anchor cables, raise the single props, and the longitudinal and transverse I-beams are closely attached to the roof of the roadway to realize the deep-shallow-surface coupling control of the roof of the roadway goaf.

5. The method for reverse construction of a roadway passing under a goaf in stages according to claim 1, Characterized in that, After the construction of the innermost arch of the roadway in step d is completed, a free face is formed. The surrounding rock of the arch of the roadway is excavated in a reverse direction from the inside out. After each round of excavation of the surrounding rock of the arch of the roadway is completed, the new grouted anchor cables, the original grouted anchor cables and the single props of the roadway are implemented to ensure that the I-beams at the top ends of the grouted anchor cables and the single props timely support the roof of the roadway, forming a complete roadway under the goaf. After the roadway under the goaf is stable, the single props and the I-beams are gradually removed to prepare for the excavation of the next round of roadway under the goaf.

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