A tunnel grouting method

Abstract

A tunnel grouting method, comprising the following steps: S1, for cave development area, easy mud gushing section, selecting full-section advanced pre-grouting + post-excavation radial grouting or peripheral curtain grouting + post-excavation radial grouting; S2, for fault fracture zone, syncline core section, shallow soft rock section, and section with buildings or reservoirs on the surface and shallow tunnel depth, or tunnel entrance and exit located in loose accumulation section, mainly using advanced anchor or advanced small conduit pre-grouting + post-excavation radial grouting, supplemented by peripheral curtain grouting + post-excavation radial grouting, and adopting pipe roof, steel arch or grid steel frame reinforcement measures; S3, for joint fissure intensive zone, fracture zone, water-rich zone and soft rock section, using advanced anchor, advanced small conduit auxiliary, water-assisted excavation to quickly pass through, and then taking radial grouting supplementary treatment measures according to requirements.

Description

Technical Field

[0001] This application relates to the field of tunnel construction, and more specifically, to a tunnel grouting method. Background Technology

[0002] The tunnel exit passes through multiple sections of soluble and insoluble rock. During construction, karst caves may be encountered at any time. If water or mud inrush occurs in the karst and insoluble rock areas, the construction principle of "first control water, strengthen support, quickly close and line early" must be adhered to.

[0003] As underground engineering waterproofing and water control construction progresses, environmental problems such as groundwater loss and pollution in the construction area will affect the lives of residents in the project area. This requires construction units to strictly control the quality of waterproofing and water control construction, strictly control groundwater loss, and adopt the principle of "blocking as the main method and limiting discharge".

[0004] Small karst caves or cavities exist in the tunnel arch, sidewalls, or bottom, with almost no filling material or water inside. They can be completely filled with coarse and fine aggregates such as sand and gravel, masonry rubble, dry rubble, cement mortar, and concrete. Grouting reinforcement can be carried out if necessary. If there is a small amount of water flowing in the cavity, the filling should not completely block the water passage of the groundwater.

[0005] The karst caves at the bottom of the tunnel are filled with loose or soft plastic clay or sandy clay deposits. In order to prevent the structure from consolidating and settling during train operation, the treatment of the foundation should be strengthened. The treatment of the bottom of the tunnel can be carried out by grouting reinforcement, replacement, pile foundation and other methods.

[0006] Therefore, those skilled in the art need to devise different grouting schemes based on the different geological conditions of the tunnel. Summary of the Invention

[0007] The main purpose of this application is to provide a tunnel grouting method that adopts corresponding grouting techniques according to different geological conditions, effectively protecting the groundwater environment and preventing it from affecting the production, life and ecological environment of local residents.

[0008] To achieve the above objectives, firstly, this application provides a tunnel grouting method, comprising the following steps:

[0009] S1. For areas with karst cave development and sections prone to mudslides and water inrushes, geological prediction and forecasting should be used as the basis for construction. Multiple factors such as water content of the rock mass, connectivity between surface water and groundwater, integrity of the rock mass, construction safety, and environmental protection should be evaluated. Full-section pre-grouting + radial grouting after excavation or perimeter curtain grouting + radial grouting after excavation should be selected.

[0010] S2. For fault fracture zones, syncline core sections, shallow buried soft rock sections, and sections with buildings or reservoirs on the surface and shallow tunnel burial depth, or tunnel entrances and exits located in loose deposits, the main method is pre-grouting with advanced anchor bolts or advanced small pipes + radial grouting after excavation, supplemented by peripheral curtain grouting + radial grouting after excavation, and reinforcement measures such as pipe roof, steel arch frame or grid steel frame are adopted.

[0011] S3. For areas with dense joints and fissures, fractured zones, water-rich zones, and soft rock sections, when the rock mass has a certain self-stabilizing capacity and the self-stabilizing time after arching is more than 12 hours, advance anchor bolts and advance small guide pipes are used to assist in rapid excavation with water. Afterwards, radial grouting is used to supplement treatment measures as required.

[0012] Further improvements include the following: the full-section pre-grouting includes reinforcing the surrounding rock within a 5-8 m radius of the core area and outline of the tunnel, preventing groundwater and mud from entering the tunnel from the periphery and front, and reinforcing the surrounding rock; each reinforcement section is 20-30 m long, with large drilling and grouting volumes and a long operation cycle; other operations cannot be carried out on the working face during grouting; concrete grout stop walls are installed to resist grout and water pressure; segmented forward grouting or backward grouting using drill rods is adopted, with the grouting sequence proceeding from the outer circle to the inner circle.

[0013] A further improvement is that the peripheral curtain grouting mainly involves reinforcing the rock mass around the section of the tunnel to be excavated to prevent the rock mass from collapsing from above the tunnel; each cycle of reinforcement is 20-30 m long, and other operations at the tunnel face are stopped during grouting; segmented forward grouting, segmented backward grouting, or full-hole one-time grouting are adopted. When there are multiple rings of holes, the outer ring of holes is grouted first, then the inner ring of holes, and finally the middle ring of holes are grouted in sequence.

[0014] A further improvement is that the local grouting mainly involves sealing the fissures in the surrounding rock to reduce the amount of ground water discharged into the tunnel; it is suitable for large stream-like water outlets on the tunnel wall after tunnel excavation, small-area surface water spraying areas, top water before curtain grouting, and advanced detection holes at the tunnel face.

[0015] A further improvement is that the radial grouting is used after tunnel excavation when there is significant water leakage in the tunnel wall or when the surrounding rock is weak and the support structure deforms significantly. Radial grouting is used to achieve water blocking and drainage, as well as to reinforce the surrounding rock and limit deformation. Depending on the reinforcement thickness, drilling can be performed using a pneumatic drill or a pneumatic down-the-hole drill, while a geological drilling rig is used at the bottom of the tunnel. During grouting, the work face is operated in parallel. A full-hole, one-time grouting is used, followed by sequential and denser grouting. It is used for reinforcement and water blocking grouting after excavation of sections with dense joints and fractures and broken surrounding rock, as well as for supplementary grouting after excavation of full-section pre-grouting sections or peripheral curtain grouting sections. Radial grouting is also used to reinforce sections affected by tunnel collapses.

[0016] A further improvement is that the pre-grouting of the advanced small guide pipe includes installing a guide pipe in the grouting hole, and the guide pipe is connected to the support steel frame, which serves as a pipe roof while reinforcing the structure with grouting.

[0017] A further improvement is that the geological prediction and forecast includes:

[0018] Morphological survey of karst and fault fracture zones: Investigate the morphology, scale, distribution location, elevation, extension direction, water inflow, and infilling material of karst.

[0019] Surface monitoring: Based on the provided engineering geological and hydrogeological maps, monitoring will be conducted on springs and wells that are closely related to residents' lives and production on both sides of the centerline of the karst tunnel. The monitoring content mainly includes changes in water volume, water temperature, water pressure, water quality, as well as local weather and precipitation.

[0020] Geological information collection and processing.

[0021] A further improvement is that the geological prediction and forecast are compiled by the geological information system. This includes acquiring new geological information from the construction process after adopting new construction methods and support parameters, updating the geological information system, processing it, and then feeding it back to the construction team. This process is repeated to form a systematic geological information system.

[0022] The tunnel grouting method provided by this invention has the following advantages compared with the prior art:

[0023] Depending on the purpose of grouting, grouting construction schemes include full-section pre-grouting, peripheral curtain grouting, local grouting, top-water grouting, radial grouting, and pre-grouting with small guide pipes. Grouting is used to improve weak and fractured rock masses, seal groundwater and corrosive ions, and solve adverse geological conditions such as faults, karst caves, soft rock and groundwater in the current construction of long tunnels. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0025] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be used interchangeably where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0027] In addition, the term "multiple" should mean two or more.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present application will now be described in detail with reference to the embodiments.

[0029] A tunnel grouting method includes the following steps:

[0030] S1. For areas with karst cave development and sections prone to mudslides and water inrushes, geological prediction and forecasting should be used as the basis for construction. Multiple factors such as water content of the rock mass, connectivity between surface water and groundwater, integrity of the rock mass, construction safety, and environmental protection should be evaluated. Full-section pre-grouting + radial grouting after excavation or perimeter curtain grouting + radial grouting after excavation should be selected.

[0031] S2. For fault fracture zones, syncline core sections, shallow buried soft rock sections, and sections with buildings or reservoirs on the surface and shallow tunnel burial depth, or tunnel entrances and exits located in loose deposits, the main method is pre-grouting with advanced anchor bolts or advanced small pipes + radial grouting after excavation, supplemented by peripheral curtain grouting + radial grouting after excavation, and reinforcement measures such as pipe roof, steel arch frame or grid steel frame are adopted.

[0032] S3. For areas with dense joints and fissures, fractured zones, water-rich zones, and soft rock sections, when the rock mass has a certain self-stabilizing capacity and the self-stabilizing time after arching is more than 12 hours, advance anchor bolts and advance small guide pipes are used to assist in rapid excavation with water. Afterwards, radial grouting is used to supplement treatment measures as required.

[0033] The full-section advanced pre-grouting includes reinforcing the surrounding rock within a core area in front of the tunnel and within a range of 5-8 m outside the outline, preventing groundwater, mud, etc. from rushing into the tunnel from the tunnel perimeter and front, and reinforcing the surrounding rock of the tunnel; each reinforcement section is 20-30 m long, with large drilling and grouting volumes and long operation cycles; other operations on the working face cannot be carried out during grouting; concrete grout stop walls are set up to resist grout and water pressure; segmented forward grouting or backward grouting using drill rods is adopted, and the grouting sequence is carried out from the outer circle to the inner circle.

[0034] The peripheral curtain grouting mainly aims to reinforce the rock mass around the section of the tunnel to be excavated, preventing the rock mass from collapsing from above the tunnel. Each cycle of reinforcement is 20-30 m long. During grouting, other operations at the tunnel face are stopped. The grouting can be done in a segmented forward or segmented backward manner, or in a one-time full-hole grouting. When there are multiple rings of holes, the outer ring of holes is grouted first, then the inner ring of holes, and finally the middle ring of holes in sequence.

[0035] The local grouting mainly involves sealing the fissures and streams of water flowing through the surrounding rock, thereby reducing the amount of ground water discharged into the tunnel. It is suitable for areas with large streams of water flowing out of the tunnel wall after excavation, small areas of surface water spraying, top water before curtain grouting, and advanced detection holes at the tunnel face.

[0036] Radial grouting is used after tunnel excavation when there is significant water leakage in the tunnel wall or when the surrounding rock is weak and the support structure deforms significantly. Radial grouting aims to stop water leakage, reinforce the surrounding rock, and limit deformation. Depending on the reinforcement thickness, drilling can be performed using pneumatic drills or pneumatic down-the-hole drills. Geological drilling rigs are used at the bottom of the tunnel. During grouting, the work face is operated in parallel. Grouting is performed in a single, full-hole operation, with sequential and denser grouting. It is used for reinforcement and water-stopping grouting after excavation of sections with dense joints and fractures and broken surrounding rock, as well as for supplementary grouting after excavation of full-section pre-grouting sections or peripheral curtain grouting sections. Radial grouting is also used to reinforce sections affected by tunnel collapses.

[0037] The pre-grouting of the advanced small guide pipe includes installing a guide pipe in the grouting hole. The guide pipe is connected to the support steel frame, and the grouting reinforcement serves as a pipe roof.

[0038] Advanced geological forecasting measures: Based on the different geological conditions of the tunnel, advanced geological work adopts a combination of long-term and short-term methods, comparison between upper and lower levels, and a combination of qualitative and quantitative methods to ensure the accuracy of forecasts. During construction, TSP (Through-the-Air Detector) and infrared water detectors are consistently used for long-distance geological prediction and forecasting. At the tunnel face, geological drilling rigs are used to further investigate and verify the karst locations identified using TSP and infrared water detectors.

[0039] Other geological work content

[0040] Morphological survey of karst and fault fracture zones: Investigate the morphology, scale, distribution location, elevation, extension direction, water inflow, and infilling material of karst.

[0041] Surface monitoring: Based on the provided engineering geological and hydrogeological maps, monitoring will be conducted on springs and wells that are closely related to residents' lives and production, located one kilometer on each side of the karst tunnel's centerline. The monitoring will primarily focus on changes in water volume, temperature, pressure, and quality, as well as local weather and precipitation.

[0042] If necessary, the pilot tunnel method should be used for excavation to reveal geological conditions;

[0043] Geological information collection and processing.

[0044] Advanced geological forecasting establishes a geological information system, collecting geological information through various methods, conducting comprehensive analysis and judgment, compiling information forecast results, which are then reviewed by senior technical personnel and submitted to the design and supervision teams. This provides a basis for decision-making regarding design and construction changes, allowing for timely adjustments to construction methods and support parameters. The analyzed and organized geological data is archived as construction technical data. When new construction methods and support parameters are adopted, new geological information is obtained during construction, updating the geological information system. After processing, this information is fed back to the construction team, and this process is repeated, forming a systematic geological information system.

[0045] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A tunnel grouting method, characterized in that, Includes the following steps: S1. For areas with karst cave development and sections prone to mudslides and water inrushes, geological prediction and forecasting should be used as the basis for construction. Multiple factors such as water content of the rock mass, connectivity between surface water and groundwater, integrity of the rock mass, construction safety, and environmental protection should be evaluated. Full-section pre-grouting + radial grouting after excavation or perimeter curtain grouting + radial grouting after excavation should be selected. S2. For fault fracture zones, syncline core sections, shallow buried soft rock sections, and sections with buildings or reservoirs on the surface and shallow tunnel burial depth, or tunnel entrances and exits located in loose deposits, the main method is pre-grouting with advanced anchor bolts or advanced small pipes + radial grouting after excavation, supplemented by peripheral curtain grouting + radial grouting after excavation, and reinforcement measures such as pipe roof, steel arch frame or grid steel frame are adopted. S3. For areas with dense joints and fissures, fractured zones, water-rich zones, and soft rock sections, when the rock mass has a certain self-stabilizing capacity and the self-stabilizing time after arching is more than 12 hours, advance anchor bolts and advance small guide pipes are used to assist in rapid excavation with water. Afterwards, radial grouting supplementary treatment measures are taken as required. The full-section advanced pre-grouting includes reinforcing the surrounding rock within a 5-8 m range outside the core area and outline of the tunnel, preventing groundwater and mud from entering the tunnel from the periphery and front, and reinforcing the surrounding rock. Each reinforcement section is 20-30 m long, with large drilling and grouting volumes and a long operation cycle. Other operations on the working face cannot be carried out during grouting. Concrete grout stop walls are set up to resist grout and water pressure. Segmented forward grouting or backward grouting using drill rods is adopted, with the grouting sequence proceeding from the outer circle to the inner circle. Radial grouting is used after tunnel excavation when there is significant water leakage in the tunnel wall or when the surrounding rock is weak and the support structure deforms significantly. Radial grouting aims to stop water leakage, reinforce the surrounding rock, and limit deformation. Depending on the reinforcement thickness, drilling is performed using pneumatic drills or pneumatic down-the-hole drills, while geological drilling rigs are used at the tunnel bottom. During grouting, the work face operates in parallel. Grouting is performed in a single, full-hole operation, with sequential and denser grouting. It is used for reinforcement and water-stopping grouting after excavation of sections with dense joints and fractures and broken surrounding rock, as well as for supplementary grouting after excavation of full-section pre-grouting sections or peripheral curtain grouting sections. Radial grouting is also used to reinforce sections affected by tunnel collapses.

2. The tunnel grouting method as described in claim 1, characterized in that: The peripheral curtain grouting mainly aims to reinforce the rock mass around the section of the tunnel to be excavated, preventing the rock mass from collapsing from above the tunnel. Each cycle of reinforcement is 20-30 m long. During grouting, other operations at the tunnel face are stopped. The grouting can be done in a segmented forward or segmented backward manner, or in a one-time full-hole grouting. When there are multiple rings of holes, the outer ring of holes is grouted first, then the inner ring of holes, and finally the middle ring of holes in sequence.

3. The tunnel grouting method as described in claim 1, characterized in that: The pre-grouting of the advanced small guide pipe includes installing a guide pipe in the grouting hole. The guide pipe is connected to the support steel frame, and the grouting reinforcement serves as a pipe roof.

4. The tunnel grouting method as described in claim 1, characterized in that: The geological predictions and forecasts include: Morphological survey of karst and fault fracture zones: Investigate the morphology, scale, distribution location, elevation, extension direction, water inflow, and infilling material of karst. Surface monitoring: Based on the provided engineering geological and hydrogeological maps, springs and wells that are closely related to residents' lives and production will be monitored on both sides of the centerline of the karst tunnel. The monitoring content mainly includes changes in water volume, water temperature, water pressure, water quality, as well as local weather and precipitation. Geological information collection and processing.

5. The tunnel grouting method as described in claim 4, characterized in that: The geological prediction and forecast are compiled by the geological information system. This includes adopting new construction methods and support parameters, obtaining new geological information from the construction process, updating the geological information system, processing it, and then feeding it back to the construction. This process is repeated to form a systematic geological information system.