A construction method for treating local holes in a tunnel passing through a goaf
The holes in the tunnel goaf are processed through spray mixing filling and grouting methods, which solves the risk of hole collapse in tunnel construction, and achieves safe and efficient tunnel construction and reduces costs.
Patent Information
- Application Number
- CN202210449988.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-04-26
- Publication Date
- 2025-08-22
- Estimated Expiration
- 2042-04-26
AI Technical Summary
There is a risk of large-scale collapse in geological sections such as holes and fall zones caused by tunnels passing through goafs or goafs, which affects construction safety and is difficult to effectively deal with in the existing technology.
The holes are treated by spray mixing filling, grouting outside the tunnel and grouting inside the tunnel, including spray concrete filling, grouting outside the tunnel surface drilling, direct grouting in the tunnel, etc., to form a closed environment and fill the gaps behind the initial branch.
It improves construction safety, ensures the stability of the initial branch and surrounding rock of the tunnel, reduces the spillover of harmful gases, has fast construction speed and low cost, and avoids the disadvantages of traditional dry-machined stone and C20 concrete filling.
Smart Images
Figure CN114718641B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of tunnels, and in particular relates to a construction method for treating local holes in a tunnel passing through a goaf. Background Art
[0002] In recent years, with the development of transportation engineering, tunnel construction within goaf areas has become commonplace. Tunnels passing through goaf areas, or the holes and caving zones created by these areas, present a risk of large-scale collapse, significantly impacting construction safety and making accidents highly likely. Therefore, to ensure the safety of tunnels passing through goaf areas, it is essential to address the local holes within these areas. Summary of the Invention
[0003] The purpose of the present invention is to provide a construction method for treating local holes in a tunnel passing through a goaf, so as to solve the problems existing in the prior art.
[0004] In order to achieve the above object, the present invention provides the following technical solutions:
[0005] A construction method for treating local holes in a tunnel passing through a goaf, the construction method comprising the following steps:
[0006] Step S10, determining the location of the local hole where the tunnel passes through the goaf;
[0007] Step S20, determining a hole treatment method according to the location of the hole and treating the hole, wherein the hole treatment method includes spray-mix filling, grouting outside the tunnel, and grouting inside the tunnel;
[0008] Step S30: After the grouting is completed, the holes behind the primary support are retested, and the secondary lining construction is carried out after the retest is qualified.
[0009] Optionally, in step S20, when the holes are located in the arch waist and the upper part of the arch waist, the hole treatment method is spray-mix filling or grouting outside the tunnel.
[0010] Optionally, when the depth of the hole is no more than 1m, the hole treatment method is spray-mix filling, specifically: first use sprayed concrete to fill the hole, and then install the steel arch frame and spray concrete support.
[0011] Optionally, when the depth of the hole is greater than 1m, the hole treatment method is grouting outside the tunnel, and the hole is treated by the method of first supporting and then grouting outside the tunnel. Specifically, the steel arch frame is installed and the sprayed concrete support is carried out first. After the strength of the sprayed concrete reaches more than 75%, the hole grouting is carried out by grouting outside the tunnel; among which, grouting outside the tunnel includes surface drilling grouting outside the tunnel and grouting of reserved pipes outside the tunnel.
[0012] Optionally, when the hole locations are continuous, the hole depth is not less than 20m and the hole volume is not less than 500m 3 When grouting outside the tunnel is carried out by drilling holes outside the tunnel, the hole grouting is carried out by drilling holes outside the tunnel. Specifically, the hole position coordinates are collected, vertical holes are drilled on the surface according to the hole position coordinates, and the hole grouting operation is carried out by using the slurry station in the goaf. The grouting operation adopts intermittent grouting, and the grouting volume does not exceed 50m per day. 3 .
[0013] Optionally, when the hole location is discontinuous, the depth is less than 20m and the hole volume is less than 500m 3 When grouting outside the tunnel, the reserved pipe grouting outside the tunnel is used. The hole grouting is carried out by using the reserved pipe grouting outside the tunnel. Specifically, a grouting pipe is reserved at the hole position outside the tunnel to carry out grouting operations.
[0014] Optionally, in step S20, when the hole is located in the underlying goaf, the hole treatment method is grouting in the tunnel, and the grouting in the tunnel includes direct grouting through drilling in the tunnel, indirect grouting through drilling in the tunnel, and grouting through a reserved pipeline in the tunnel.
[0015] Optionally, when the hole area is not larger than 500m 2 In the case of tunnel grouting, the holes are filled by direct grouting through holes drilled in the tunnel.
[0016] Optionally, when the hole area is larger than 500m 2 Grouting in the tunnel is indirect grouting through drilling holes in the tunnel. Specifically, a geological drill is used to drill holes in the tunnel, and grouting is performed after the drilling is completed. The slurry is introduced from the goaf into a grouting pipe through the reserved ventilation holes in the tunnel, and the grouting pipe enters the tunnel to perform grouting operations on the holes.
[0017] Optionally, when the length of the hole along the tunnel axis is greater than 24m, and the actual construction time of the hole treatment exceeds the normal construction time by more than 5 days, the grouting in the tunnel is grouting of the reserved pipe in the tunnel, specifically: reserving a pipe at the tunnel invert arch, and performing grouting in the reserved pipe after the construction of the tunnel invert arch is completed. After the grouting is completed, the reserved hole in the tunnel is filled with micro-expansive concrete.
[0018] Beneficial effects:
[0019] The construction method of the present invention utilizes a combination of spray-mix filling, external grouting, and internal grouting to treat the holes. This method is highly effective, effectively filling the voids in the rock surrounding the primary support, stabilizing the surrounding rock and treating the voids behind the primary support, thereby effectively ensuring the safety of tunnel construction through goafs. Grouting fills the holes behind the primary support, eliminating the need for supporting formwork and preventing the filling operation from interfering with the normal tunnel construction cycle. This method is simple and highly efficient, compared to traditional construction methods that utilize dry-laid rubble, C20 rubble concrete, and C20 concrete for filling. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] The accompanying drawings, which constitute part of the present invention, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. Among them:
[0021] Figure 1 A schematic diagram of a tunnel passing through a goaf according to some embodiments of the present invention, wherein the local holes are located at the haunch and above;
[0022] Figure 2 Schematic diagram of a tunnel passing through a goaf with local holes located at or above the arch waist according to other embodiments of the present invention;
[0023] Figure 3 A schematic diagram of a tunnel passing through a goaf provided by some embodiments of the present invention, wherein a local hole is located in an underlying goaf;
[0024] Figure 4 Schematic diagram of a tunnel passing through a goaf in accordance with some other embodiments of the present invention, in which local holes are located in an underlying goaf.
[0025] Numbers in the figure: 1-tunnel; 2-hole. DETAILED DESCRIPTION
[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.
[0027] The present invention will be described in detail below with reference to the embodiments. It should be noted that the embodiments and features of the embodiments of the present invention can be combined with each other without conflict.
[0028] The present invention provides a construction method for treating local holes in a tunnel passing through a goaf. When a tunnel 1 passes through a goaf, the construction method of the present invention can quickly support and form a closed environment to reduce the spillage of harmful gases, while forming construction protection and effectively improving the safety factor. The back of the primary support is filled by spraying and filling, grouting outside the tunnel 1, grouting inside the tunnel 1 and other hole treatment methods, so that the primary support and the surrounding rock surface form a closed environment, and the entire range outside the primary support can be effectively filled. In addition, during the filling process, the lower part of the primary support structure is affected by the gravity of the slurry, and the bottom is fully self-pressurized, so that the back of the primary support can be dense. The construction method of the present invention has the following characteristics: (1) High safety factor: The construction method of the present invention can quickly form an initial support. After the initial support is completed, the falling blocks formed in the excavation process of the caving zone caused by the goaf are supported by the initial support, and no direct damage will occur. Moreover, deformation and cracking of the steel frame are easily discovered during monitoring, which can effectively warn of risks. (2) High quality: The construction method of the present invention performs grouting by grouting the surface outside the tunnel 1 or the reserved holes 2 of the primary support in the tunnel 1. The grouting effect is good and can effectively fill the rock voids outside the primary support, which has a good effect on the stability of the surrounding rock and the treatment of the voids behind the primary support of the tunnel. (3) High efficiency: The construction method of the present invention fills the holes 2 behind the primary support by grouting. Compared with the traditional construction process using dry stone, C20 stone concrete and C20 concrete filling construction, no supporting formwork is required, and the filling operation does not affect the normal cycle construction of the tunnel. The construction method is simple and the efficiency is high.
[0029] The construction method of the present invention is to use initial support to timely seal the space, perform grouting construction in the hole 2, and use the fluidity of the slurry to effectively fill the holes and gaps, which can achieve good hole treatment effects and has a significant effect on sealing harmful gases and filling gaps and holes.
[0030] The construction method for treating local holes in a tunnel passing through a goaf of the present invention comprises the following steps:
[0031] Step S10, determining the position of the local hole 2 where the tunnel 1 passes through the goaf;
[0032] Step S20, determining a hole treatment method according to the position of the hole 2, and treating the hole 2, wherein the hole treatment method includes spray-mix filling, grouting outside the tunnel 1, and grouting inside the tunnel 1;
[0033] Step S30: After the hole treatment is completed, the hole 2 behind the primary support is re-tested, and the secondary lining construction is carried out after the re-test is qualified.
[0034] The locations of holes caused by tunnels passing through goafs can be selected as Tunnel 1's arch haunch and above, and the underlying goaf. Hole 2 in Tunnel 1's arch haunch and above can be directly observed and does not require inspection. However, holes in the underlying goaf require inspection. Specifically, because goaf inspection only inspects individual points in each section, the inspection results may not cover all situations. Therefore, during Tunnel 1 excavation, targeted treatment is performed based on the results of geological radar tunnel bottom scanning. During the excavation process, Tunnel 1 performs tunnel bottom inspection at the front end of the invert arch. If both the goaf inspection and tunnel bottom inspection pass, the goaf treatment is considered to meet the design requirements. If the tunnel bottom inspection reveals Hole 2, it needs to be treated.
[0035] It should be noted that since holes at the arch waist and above are directly observable during excavation, these holes require support followed by grouting. However, holes discovered during tunnel bottom inspection are covered by support and surrounding rock and therefore do not require support before grouting.
[0036] In an optional embodiment of the present invention, when the hole 2 is located at the waist of the tunnel 1 and the upper part of the waist (that is, located at the waist of the tunnel and above), the hole treatment method is spray-mixed filling or grouting outside the tunnel 1, and the specific operation is determined according to the depth of the hole.
[0037] In a specific embodiment of the present invention, when the depth of the hole 2 created by the goaf is no greater than 1m, the hole treatment method is shotcrete filling. Specifically, the hole 2 is first filled with shotcrete, followed by the installation of the steel arch and the use of shotcrete support. During the construction treatment process, the hole 2 is filled with shotcrete. An initial shotcrete is performed before the steel arch is erected to fill the hole 2 tightly. The steel arch is then installed and the shotcrete support is constructed.
[0038] When the depth of the hole 2 created by the goaf exceeds 1m, the hole treatment method is grouting outside the tunnel, and the hole treatment method is to first support and then grouting. Specifically, because the filling of shotcrete takes too long, in order to ensure the construction safety of tunnel 1, initial support is carried out first, that is, steel arch installation and shotcrete support are carried out first. After the shotcrete strength reaches more than 75%, the hole 2 is grouted using the method of grouting outside the tunnel. The grouting operation is determined by the location and depth of the hole 2. Among them, the grouting outside the tunnel includes grouting through surface drilling outside the tunnel and grouting through the reserved pipe outside the tunnel. The specific grouting operation is determined by the location and size of the hole 2.
[0039] like Figure 1 As shown, when the hole 2 position is continuous, the hole 2 depth is not less than 20m and the hole 2 volume is not less than 500m 3When the tunnel is grouting outside the tunnel, the surface drilling grouting outside the tunnel is used for hole grouting. Specifically, the position coordinates of hole 2 are collected, vertical drilling is carried out on the surface according to the position coordinates of hole 2, and hole grouting is carried out at the goaf grouting station. The grouting operation adopts intermittent grouting, and the grouting volume does not exceed 50m per day. 3 .
[0040] Furthermore, during the grouting process, monitoring and measurement work inside the tunnel was strengthened to prevent excessive grouting from causing arch deformation. After grouting, the primary support quality was inspected. This inspection used radar scanning and in-hole TV imaging, which were mutually verified. Subsequent processing was carried out based on the inspection results. If the backholes were densely filled after the inspection, the goaf behind the primary support section was treated. If the inspection results revealed that some voids still existed locally, in-hole grouting technology was used to carry out targeted grouting of the voids. After the invert arch reached the loose area, a hole was drilled and piped into the primary support concrete (reserving a grouting pipe). A ground pump was connected to the grouting hole, and hole 2 was filled with premixed M20 mortar from the mixing station. After filling, a retest was conducted, using radar scanning and in-hole TV imaging to verify each other. Secondary lining construction could only proceed after passing the inspection.
[0041] like Figure 2 As shown, when the hole 2 is discontinuous, the depth is less than 20m and the volume of hole 2 is less than 500m 3 When grouting outside the tunnel, the reserved pipe grouting outside the tunnel is used. The hole grouting is carried out by the reserved pipe grouting outside the tunnel. Specifically, the grouting pipe is directly reserved at the position of hole 2 outside the tunnel. The embedded pipe is fixed when supporting the shotcrete. The shotcrete is completed to form a reserved hole. When the invert arch is constructed to this position, the grouting operation is carried out. The ground pump is connected to the grouting hole (that is, the reserved hole). The mixing station is used to pre-mix M20 mortar to fill the hole 2. After the filling is completed, re-testing is carried out. Only after passing the test can the secondary lining construction be carried out.
[0042] When hole 2 is located in the underlying goaf (that is, hole 2 is detected at the bottom of the tunnel), the hole treatment method is grouting in tunnel 1. The grouting in the tunnel includes direct grouting through drilling holes in the tunnel, indirect grouting through drilling holes in the tunnel, and grouting through reserved pipes in the tunnel. The specific grouting operation is determined according to the hole area.
[0043] Alternatively, as Figure 3 As shown in the figure, when the scanning results show that the area of the hole 2 at the bottom of the tunnel is not larger than 500m 2In this case, grouting in the tunnel involves direct grouting through drilled holes within the tunnel. Specifically, hole 2 is filled using direct grouting through drilled holes within the tunnel. Specifically, the location of hole 2 is located by scanning, and then staked out on the original ground. Drilling and grouting are then performed according to the staked-out location. Based on the grouting results, additional holes are determined for goaf treatment. The specific construction process is the same as that for goaf treatment.
[0044] The specific construction process for goaf treatment is as follows: full-fill pressure grouting method is adopted, that is, sufficient curtain holes and grouting holes are arranged on the surface, the curtain holes are at the boundary, the grouting holes are located in the middle area, the spacing between the curtain holes is set to 10m, and the spacing between the grouting holes is set to 10-15m (such as 10m, 11m, 12m, 13m, 14m, 15m and the interval between any two end points), and the drilling rig is used to wet drill holes, drill holes on the surface, reach 0.5m below the bottom plate of the goaf, and fill the grouting pipes tightly. Sealed in the overlying rock strata in the coal mine goaf, a mud pump is used to inject cement fly ash slurry with a water-solid ratio of 1:1-1:1.3 (such as 1:1, 1:1.1, 1:1.2, 1:1.3 and the interval value between any two endpoints) into the collapsed area of the coal mine goaf and the fracture zone of the overlying rock strata. The slurry is solidified and cemented to form the fracture zone of the rock strata. At the same time, the stone body formed by the slurry in the goaf supports the overlying rock strata, preventing the overlying rock strata from further falling and collapsing, thereby ensuring the stability of the structure and construction safety.
[0045] It should be noted that when the hole 2 is detected as a tunnel bottom hole with an area of no more than 500m 2 When the grouting volume is greater than 500m 3 In-hole grouting (i.e., grouting through the reserved pipes in Tunnel 1) takes a long time, significantly impacts construction, and is costly. Drilling grouting in Tunnel 1 can be used to minimize the impact on Tunnel 1 construction. Overall, for cost reasons, if drilling costs are high, grouting through the reserved pipes in Tunnel 1 is the primary method.
[0046] like Figure 4 As shown in the figure, when the scanning results show that the area of the hole 2 at the bottom of the tunnel is larger than 500m 2 In this case, drilling outside the tunnel 1 is not feasible. Grouting within the tunnel is performed indirectly through drilling holes within the tunnel. The construction method of the present invention utilizes a geological drill to drill holes within the tunnel 1. Grouting is then performed after completion. Slurry is introduced from the goaf through a grouting pipe, pre-reserved ventilation holes in the tunnel 1. The grouting pipe then enters the tunnel 1 to grout the holes. After grouting is completed, a retest is conducted. Only after the scan results are satisfactory can primary support and secondary lining construction be carried out.
[0047] When the length of the hole appearing at the bottom of the tunnel along the axis of tunnel 1 is greater than 24m (i.e., the length of the two-plate secondary lining), and the actual construction time for treating hole 2 exceeds the normal construction time by more than 5 days, the treatment of hole 2 requires a larger aperture and time, and the grouting method outside the tunnel cannot be used. In order to avoid the impact of drilling and grouting construction in the underlying goaf on the safe step distance of the tunnel, the grouting in the tunnel is grouting in the reserved pipes in the tunnel. Specifically, a pipe is reserved at the invert arch of tunnel 1, and grouting operations are carried out in the reserved pipes after the construction of the invert arch of tunnel 1 is completed. After the grouting is completed, the reserved holes of tunnel 1 are filled with micro-expansive concrete to prevent water leakage in the reserved holes.
[0048] It should be noted that the raw materials of the grouting slurry include: cement, fly ash, accelerator, and mortar. Among them, the cement can be ordinary Portland cement with a strength grade of 42.5. The fly ash should meet the national second and third level quality standards and should not contain lumps, humus or other impurities. The total content of SiO2, Al2O3 and Fe2O3 should be greater than 70%, the SO3 content should not exceed 3%, the loss on ignition of the fly ash should not exceed 12%, and the specific surface area of the fly ash should be greater than 2500cm 2 / g. The quick-setting agent is water glass, the modulus of which can be selected as 2.4-3.4, and the concentration is above 50°Be'.
[0049] Optionally, during the grouting process, a high-precision pressure gauge is used to strictly control the stop injection pressure to be greater than 1.5 MPa, and the stop injection pressure is recorded to ensure that the grouting volume is less than 70 L / min and the duration is greater than 15 minutes.
[0050] In order to control the quality of the filling effect of hole 2, grouting observation holes are set every 3 meters in the circumferential direction after the initial support is completed. When grouting is carried out on the outside, the grouting observation holes begin to flow slurry, proving that the part below this position has been grouted. The observation holes are sealed and the grouting operation is continued until all the grouting holes are fully flowed and sealed.
[0051] After all observation holes are sealed, stop grouting and take a break for 2-3 days. Wait until the slurry strength reaches more than 50% for the second grouting. When the grouting pressure reaches 1.5MPa and lasts for more than 15 minutes, and the grouting volume is less than 70L / min, stop grouting and the treatment work is completed.
[0052] The construction method of the present invention adopts spray-mix filling, grouting outside the tunnel (including grouting through surface drilling outside the tunnel and grouting through reserved pipes outside the tunnel), grouting inside the tunnel (including direct grouting through drilling inside the tunnel, indirect grouting through drilling inside the tunnel and grouting through reserved pipes inside the tunnel), etc., to replace the dry-laid rubble backfill and rubble concrete backfill construction processes. The construction speed is fast, the process is simple, and the safety risk is small. It is a more scientific and economical method for the construction of hole treatment in goaf areas.
[0053] The proposed construction method eliminates dry-stone paving within the goaf. By utilizing the enclosed space provided by the primary support, post-grouting significantly reduces construction safety risks. Furthermore, the entire construction process does not affect tunnel operations, effectively improving construction progress. Grouting replaces C20 concrete filling, offering excellent fluidity, a high fill rate, and the ability to effectively fill gaps between rock layers, achieving excellent quality results.
[0054] Through calculation and comparison, it can be seen that the construction method of the present invention can save 900,000 yuan in construction costs compared with the original plan.
[0055] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.
Claims
1. A construction method for treating local holes in a tunnel passing through a goaf, characterized in that: The construction method comprises the following steps: Step S10, determining the location of the local hole where the tunnel passes through the goaf; Step S20, determining a hole treatment method according to the location of the hole and treating the hole, wherein the hole treatment method includes spray-mix filling, grouting outside the tunnel, and grouting inside the tunnel; In step S30, after the hole treatment is completed, the holes behind the primary support are re-tested, and the secondary lining construction is carried out after the re-test is qualified. In step S20, when the hole is located in the arch waist and the upper part of the arch waist, the hole treatment method is spray-mixed filling or grouting outside the tunnel. When the hole depth is not more than 1m, the hole treatment method is spray-mixed filling, specifically: first use sprayed concrete to fill the hole, and then install the steel arch frame and sprayed concrete support. When the hole depth is greater than 1m, the hole treatment method is grouting outside the tunnel, and the hole is treated by supporting first and then grouting outside the tunnel, specifically: first install the steel arch frame and sprayed concrete support, after the sprayed concrete strength reaches more than 75%, the hole grouting is carried out by grouting outside the tunnel; wherein, grouting outside the tunnel includes surface drilling grouting outside the tunnel and grouting of reserved pipes outside the tunnel. When the hole position is continuous, the hole depth is not less than 20m and the hole volume is not less than 500m 3 When grouting outside the tunnel is carried out by drilling holes outside the tunnel, the hole grouting is carried out by drilling holes outside the tunnel. Specifically, the hole position coordinates are collected, vertical holes are drilled on the surface according to the hole position coordinates, and the hole grouting operation is carried out by using the slurry station in the goaf. The grouting operation adopts intermittent grouting, and the grouting volume does not exceed 50m per day. 3 , when the hole position is discontinuous, the depth is less than 20m and the hole volume is less than 500m 3 When grouting outside the tunnel, the reserved pipe grouting outside the tunnel is used. The hole grouting is carried out by using the reserved pipe grouting outside the tunnel. Specifically, a grouting pipe is reserved at the hole position outside the tunnel to carry out grouting operations.
2. The construction method for treating local holes in a tunnel passing through a goaf according to claim 1, characterized in that: In step S20, when the hole is located in the underlying goaf, the hole treatment method is grouting in the tunnel, and the grouting in the tunnel includes direct grouting through drilling in the tunnel, indirect grouting through drilling in the tunnel, and grouting through a reserved pipeline in the tunnel.
3. The construction method for treating local holes in a tunnel passing through a goaf according to claim 2, characterized in that: When the hole area is not larger than 500m 2 In the case of tunnel grouting, the holes are filled by direct grouting through holes drilled in the tunnel.
4. The construction method for treating local holes in a tunnel passing through a goaf according to claim 2, characterized in that: When the hole area is larger than 500m 2 Grouting in the tunnel is indirect grouting through drilling holes in the tunnel. Specifically, a geological drill is used to drill holes in the tunnel, and grouting is performed after the drilling is completed. The slurry is introduced from the goaf into a grouting pipe through the reserved ventilation holes in the tunnel, and the grouting pipe enters the tunnel to perform grouting operations on the holes.
5. The construction method for treating local holes in a tunnel passing through a goaf according to claim 2, characterized in that: When the length of the hole along the tunnel axis is greater than 24m and the actual construction time of the hole treatment exceeds the normal construction time by more than 5 days, the grouting in the tunnel is the grouting of the reserved pipe in the tunnel. Specifically, a pipe is reserved at the tunnel invert, and grouting is carried out in the reserved pipe after the construction of the tunnel invert is completed. After the grouting is completed, the reserved hole in the tunnel is filled with micro-expansive concrete.