Tunnel segmental lining ring pea gravel filling method

Abstract

The invention provides a pea gravel filling method for a tunnel segment lining ring, and relates to the technical field of tunnel construction, and the pea gravel filling method comprises the following steps: S1, blow-filling pea gravels between a bottom segment of a target segment lining ring and tunnel surrounding rock; s2, blow-filling pea gravels between the bottom segment of the next adjacent to-be-blow-filled segment lining ring and the tunnel surrounding rock; s3, if the number of the lining rings of the segments subjected to hydraulic filling of the bottom segments reaches a preset value, the side segments and the top segments of the lining rings of the segments to be subjected to hydraulic filling are separated from the shield tail of the shield tunneling machine, the step S6 is executed, and if not, the steps S4-S5 are executed; s4, pea gravels between the side segment and the top segment of the lining ring of the target segment and the tunnel surrounding rock are sequentially blown and filled; s5, setting the to-be-dredger-filled segment lining ring as a target segment lining ring, and repeating the steps S2-S3; and S6, grouting is conducted on the segment lining rings subjected to bottom, side and top segment pea gravel filling in sequence. According to the method, the problem that in an existing method, due to the fact that the hydraulic reclamation sequence is random, pea gravel filling is not compact is solved through the hydraulic reclamation sequence.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a method for filling tunnel segment lining with ring-shaped gravel. Background Technology

[0002] In shield tunnel construction, gravel filling is a core process for addressing the gaps between the tunnel lining rings and the surrounding rock. The density of this filling directly affects the tunnel structure's load-bearing stability, impermeability, and long-term durability. A proper dredging process is necessary to ensure the gaps are uniformly filled with gravel, providing a good foundation for subsequent grouting and curing. Currently, some tunnel projects use honeycomb-shaped segments arranged in rings to optimize the stress performance of the tunnel lining. The structural characteristic of this type of segment is that the side segments of each ring protrude half a ring length beyond the bottom and top segments. While this structural design improves the connection strength between the segment rings, it has also caused a series of technical challenges during the gravel dredging process.

[0003] Specifically, existing gravel dredging methods are mostly designed for conventional rectangular tunnel segments. When dredging honeycomb-arranged segments, there is a lack of specific solutions adapted to their structural characteristics, and the dredging sequence is often quite random. If the gaps corresponding to the side segments are dredged first during construction, due to the gravity of the gravel itself, some gravel will naturally flow to the bottom segment area of ​​the next ring. This not only results in insufficient gravel filling in the gaps corresponding to the side segments but also causes the gravel transport path for subsequent bottom segment dredging to be blocked by the pre-accumulated gravel, preventing sufficient filling of the gaps corresponding to the bottom segments and thus creating loose areas. Such defects severely weaken the overall load-bearing capacity of the tunnel structure, easily leading to safety risks such as segment cracking, water leakage, and surrounding rock settlement, directly affecting the construction quality and long-term operational safety of the tunnel project.

[0004] Therefore, there is an urgent need for a method for filling tunnel segment lining with ring-shaped gravel that is suitable for honeycomb segment structures and can ensure the density of the filling. Summary of the Invention

[0005] The purpose of this invention is to address the above problems by providing a method for filling tunnel segment lining with ring-shaped gravel.

[0006] This invention provides a method for filling tunnel segment lining rings with gravel, wherein multiple segment lining rings are coaxially arranged and sequentially in a honeycomb pattern along their axial direction. Each segment lining ring includes a bottom segment, two side segments, and a top segment. The method includes: S1. Gravel filling is carried out between the bottom segment of the target segment lining ring and the surrounding rock of the tunnel; the target segment lining ring is the segment lining ring corresponding to the current construction position; S2. Gravel is blown into the space between the bottom segment of the lining ring to be blown in and the surrounding rock of the tunnel; the lining ring to be blown in is the next lining ring adjacent to the target lining ring. S3. If the number of lining rings filled with gravel between the bottom segment and the surrounding rock of the tunnel reaches the preset number, the side segments and top segments of the lining ring to be filled are removed from the shield tail of the tunnel boring machine, and then step S6 is executed; otherwise, steps S4-S5 are executed. S4. Gravel filling is carried out sequentially between the side segments of the target segment lining ring and the surrounding rock of the tunnel, and between the top segment of the target segment lining ring and the surrounding rock of the tunnel. S5. Take the lining ring of the segment to be filled as the target segment lining ring and execute steps S2-S3; S6. Grouting is carried out sequentially on the lining rings of the tunnel segments that have been filled with gravel between the bottom segments, side segments, and top segments and the surrounding rock of the tunnel.

[0007] According to the technical solutions provided in some embodiments of the present invention, the method further includes: Obtain the geological type of the construction area and the type of segments currently being filled with gravel; The filling strategy is determined based on the geological type of the construction area and the type of segments currently being filled with gravel.

[0008] According to the technical solutions provided in certain embodiments of the present invention, obtaining the geological type of the construction area includes: Obtain the geological resistance parameters of the surrounding rock of the tunnel in the construction area; The geological type of the construction area is determined based on the geological resistance parameters.

[0009] According to the technical solutions provided in certain embodiments of the present invention, determining the geological type of the construction area based on the geological resistance parameters includes: If the geological resistance parameter is greater than or equal to the first preset resistance threshold, then the geological type of the construction area is determined to be a hard rock section. If the geological resistance parameter is less than or equal to the second preset resistance threshold, then the geological type of the construction area is determined to be a soft rock section; the second preset resistance threshold is less than the first preset resistance threshold. If the geological resistance parameter is less than the first preset resistance threshold and greater than the second preset resistance threshold, then the geological type of the construction area is determined to be a transitional geological section.

[0010] According to the technical solutions provided in certain embodiments of the present invention, determining the dredging strategy based on the geological type of the construction area and the type of segments currently being dredged with gravel includes: The particle size distribution of the pea gravel used for dredging is determined based on the type of segments currently being dredged with pea gravel. The filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel.

[0011] According to the technical solutions provided in certain embodiments of the present invention, determining the particle size distribution of the gravel used for dredging based on the type of segments currently being dredged includes: If the segment type currently being filled with pea gravel is a bottom segment, then the particle size distribution of the pea gravel used for filling is determined to be the first particle size distribution. If the segment type currently being filled with pea gravel is a side segment, then the particle size distribution of the pea gravel used for filling the side segment is determined to be the second particle size distribution. If the segment type currently being filled with gravel is a jacking segment, then the particle size distribution of the gravel used for filling the jacking segment is determined to be the third particle size distribution. The proportion of gravel with a particle size larger than the preset particle size in the first particle size distribution is greater than the proportion of gravel with a particle size larger than the preset particle size in the second particle size distribution, and the proportion of gravel with a particle size larger than the preset particle size in the second particle size distribution is greater than the proportion of gravel with a particle size larger than the preset particle size in the third particle size distribution.

[0012] According to the technical solutions provided in certain embodiments of the present invention, the filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel, including: If the geological type of the construction area is hard rock, then the filling pressure is determined to be a first preset range; the first preset range includes a first sub-range, a second sub-range and a third sub-range, the lower boundary value of the first sub-range is greater than or equal to the upper boundary value of the third sub-range, the lower boundary value of the second sub-range is within the third sub-range, and the upper boundary value of the second sub-range is within the first sub-range; If the segment type currently undergoing gravel backfilling is a jacking segment, then the backfilling pressure of the jacking segment is determined to be the first sub-range, and the jacking segment is continuously backfilled according to the backfilling pressure within the first sub-range. If the segment type currently being filled with gravel is a bottom segment, then the filling pressure of the bottom segment is determined to be the second sub-range, and the bottom segment is continuously filled according to the filling pressure within the second sub-range. If the segment type currently being filled with gravel is a side segment, then the filling pressure of the side segment is determined to be the third sub-range, and the side segment is continuously filled according to the filling pressure within the third sub-range.

[0013] According to the technical solutions provided in certain embodiments of the present invention, the filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel, including: If the geological type of the construction area is soft rock, then the filling pressure is determined to be the second preset range; The jacking segments, bottom segments, and side segments in the soft rock section are pulsed and filled with pressure within the second preset range.

[0014] According to the technical solutions provided in certain embodiments of the present invention, the filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel, including: If the geological type of the construction area is a transitional geological section, then the filling pressure is determined to be the third preset range; Linearly adjusted filling is carried out on the jacking segments, bottom segments, and side segments in the transition geological section according to the filling pressure within the third preset range.

[0015] According to the technical solutions provided in some embodiments of the present invention, the method further includes: Obtain the gravel filling density between the segment lining ring and the tunnel surrounding rock after the bottom segment, side segment and top segment have been filled with gravel, and perform gravel supplementary filling at locations where the gravel filling density is less than the preset density threshold.

[0016] In summary, this invention provides a method for filling tunnel segment lining rings with gravel. Multiple segment lining rings are coaxially arranged and sequentially in a honeycomb pattern along their axial direction. Each segment lining ring includes a bottom segment, two side segments, and a top segment. The method includes: S1, filling the space between the bottom segment of the target segment lining ring and the surrounding rock of the tunnel with gravel; the target segment lining ring is the segment lining ring corresponding to the current construction position; S2, filling the space between the bottom segment of the segment lining ring to be filled and the surrounding rock of the tunnel with gravel; the segment lining ring to be filled is the next segment lining ring adjacent to the target segment lining ring; S3, if the bottom segment is completed... If the number of segment lining rings filled with gravel between the segment and the surrounding rock of the tunnel reaches the preset number, then the bottom segment, side segment, and top segment of the segment lining ring to be filled are removed from the shield tail of the tunnel boring machine, and then step S6 is executed; otherwise, steps S4-S5 are executed. S4: Gravel is sequentially filled between the side segment and the surrounding rock of the target segment lining ring, and between the top segment and the surrounding rock of the target segment lining ring. S5: The segment lining ring to be filled is used as the target segment lining ring, and steps S2-S3 are executed. S6: Grouting is sequentially performed on the segment lining rings that have been filled with gravel between the bottom segment, side segment, and top segment and the surrounding rock of the tunnel. This invention optimizes the gravel filling sequence of honeycomb-arranged pipe segment lining rings by first filling the bottom segments of adjacent target pipe segment lining rings and the bottom segments of the pipe segment lining ring to be filled in sequence, and then filling the side segments and top segments of the target pipe segment lining ring. This solves the technical problems of insufficient filling of the gaps between side segments, blockage of the bottom segment filling path, and incomplete filling caused by the random sequence in existing filling methods.

[0017] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this invention do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic flowchart illustrating a method for filling tunnel segment lining with pebbly gravel, provided in an embodiment of the present invention; Figure 2 This is a schematic diagram showing the structure of the segment lining ring provided in an embodiment of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. This description is merely illustrative and explanatory, and should not be construed as limiting the scope of protection of the present invention in any way. Specifically, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. 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 process, method, product, or apparatus.

[0022] As mentioned in the background section, to address the problems in the prior art, this embodiment provides a method for filling tunnel segment lining rings with gravel. Multiple segment lining rings are coaxially arranged and sequentially in a honeycomb pattern along their axial direction. Each segment lining ring includes a bottom segment, two side segments, and a top segment. Figure 1 As shown, the method includes: S1. Gravel filling is carried out between the bottom segment of the target segment lining ring and the surrounding rock of the tunnel; the target segment lining ring is the segment lining ring corresponding to the current construction position. S2. Gravel is blown into the space between the bottom segment of the lining ring to be blown in and the surrounding rock of the tunnel; the lining ring to be blown in is the next lining ring adjacent to the target lining ring. S3. If the number of segments filled with gravel between the bottom segment and the surrounding rock of the tunnel reaches the preset number, the bottom segment, side segment and top segment of the segment lining ring to be filled are removed from the shield tail of the tunnel boring machine, and then step S6 is executed; otherwise, steps S4-S5 are executed. S4. Gravel filling is carried out sequentially between the side segments of the target segment lining ring and the surrounding rock of the tunnel, and between the top segment of the target segment lining ring and the surrounding rock of the tunnel. S5. Take the lining ring of the segment to be filled as the target segment lining ring and execute steps S2-S3. S6. Grouting is carried out sequentially on the lining rings of the tunnel segments that have been filled with gravel between the bottom segments, side segments, and top segments and the surrounding rock of the tunnel.

[0023] For example, such as Figure 2 As shown, multiple segment lining rings are coaxially arranged and sequentially in a honeycomb pattern along their axial direction. Each segment lining ring includes a bottom segment, two side segments, and a top segment. In this embodiment, the net inner diameter of the segment lining ring is 5850 mm, the outer diameter is 6550 mm, the thickness is 350 mm, and the width is 1600 mm. To clearly illustrate the gravel filling process, in... Figure 2 The corresponding segment lining ring is marked in the middle, along the tunnel axis ( Figure 2In the X direction, adjacent tunnel segment lining rings are defined in the splicing order as ring A, ring B, ring C, ring D, ring E, and so on. Each ring includes bottom segments (e.g., A1, B1, C1, D1, E1), left side segments (e.g., A2, B2, C2, D2, E2), right side segments (e.g., A3, B3, C3, D3, E3), and top segments (e.g., A4, B4, C4, D4, E4). Since each tunnel segment lining ring must bear the propulsion reaction force of the tunnel boring machine, its own weight, and the weight of the gravel after assembly, grouting work needs to be carried out simultaneously on the bottom, side, and top segments that have been filled with gravel between the bottom segments and the surrounding rock when the preset number of segment lining rings reaches this threshold. In this embodiment, the preset quantity is 5 segments, but it can be adjusted according to the actual construction situation, and no specific limitation is made here. During actual construction, after the bottom segment A1, the left side segment A2, the right side segment A3, and the top segment A4 of ring A have all exited the shield tail of the tunnel boring machine, gravel is blown into the space between the bottom segment A1 of the target segment lining ring A and the surrounding rock of the tunnel through the reserved hole in the bottom segment A1. After the bottom segment A1 has completed the gravel filling and the tunnel boring machine continues to advance until the bottom segment B1 of the segment lining ring B to be filled exits the shield tail of the tunnel boring machine, gravel is blown into the space between the bottom segment B1 of the segment lining ring B and the surrounding rock of the tunnel through the reserved hole in the bottom segment B1. After the bottom segment B1 is filled with gravel, gravel is blown into the left side segment A2, right side segment A3, and top segment A4 of the target segment lining ring A. At this point, the target segment lining ring A is filled. Once the target segment lining ring A is filled and the tunnel boring machine continues to advance until the bottom segment C1 of ring C, adjacent to ring B, exits the shield tail, ring B is used as the target segment lining ring, and ring C as the segment lining ring to be blown in. Gravel is blown into the space between the bottom segment C1 of the segment lining ring C and the surrounding rock of the tunnel through the pre-drilled holes in the bottom segment C1. Following this pattern, after the bottom segment E1 of ring E (the 5th segment lining ring) is filled, the left side segment E2, the right side segment E3, and the top segment E4 of ring E are removed from the shield tail of the tunnel boring machine. Grouting is then performed on rings A, B, C, and D (i.e., the segment lining rings where the bottom, side, and top segments have been filled with gravel between themselves and the surrounding rock). The grouting involves injecting cement slurry into the already filled gravel. In this embodiment, the water-cement ratio (the mass ratio of water to cement) of the cement slurry is set to 1:1, and the grouting volume is typically 130% to 180% of the theoretical gravel gap volume (the theoretically calculated volume of the gaps formed between the gravel filling the space between the segment lining ring and the surrounding rock under ideal construction conditions). This process is repeated until all segment lining rings have completed gravel filling and grouting, thus completing the entire gravel filling construction.

[0024] This invention optimizes the gravel filling sequence of honeycomb-arranged tunnel lining rings. It adopts a filling sequence that first sequentially fills the bottom segments of adjacent target tunnel lining rings and the bottom segments of the tunnel lining ring to be filled, and then fills the side segments and top segments of the target tunnel lining ring. This solves the technical problems of insufficient filling of side segment gaps, blocked filling paths of bottom segments, and loose filling caused by the random sequence in existing filling methods. It avoids safety risks such as reduced overall bearing capacity of tunnel structure, segment cracking, water leakage, and surrounding rock settlement caused by loose gravel filling.

[0025] In a preferred embodiment, the method further includes: Obtain the geological type of the construction area and the type of segments currently being filled with gravel; The filling strategy is determined based on the geological type of the construction area and the type of segments currently being filled with gravel.

[0026] Specifically, the geological type of the construction area and the type of tunnel segments currently used for gravel dredging are determined. Different geological types and different types of tunnel segments require different dredging pressures and methods. For example, strongly weathered loose strata have a high risk of borehole collapse, and the migration path of gravel is easily blocked by collapsed rock blocks, leading to a decrease in filling efficiency and density. For jacking tunnel segments, the gravel needs to be dredged from bottom to top, requiring a higher dredging pressure than in other locations. Therefore, the dredging strategy must be determined based on the geological type of the construction area and the type of tunnel segments currently used for gravel dredging. The geological types include hard rock sections, soft rock sections, and transitional geological sections; the types of tunnel segments currently used for gravel dredging include jacking tunnel segments, bottom tunnel segments, and side tunnel segments.

[0027] In a preferred embodiment, obtaining the geological type of the construction area includes: Obtain the geological resistance parameters of the surrounding rock of the tunnel in the construction area; The geological type of the construction area is determined based on geological resistance parameters.

[0028] Specifically, geological resistance parameters of the tunnel surrounding rock in the construction area are obtained through geological resistance sensors, and the geological type of the construction area can be determined based on these parameters. In this embodiment, the geological resistance parameter is the pore seepage resistance of the tunnel surrounding rock, but other geological resistance parameters can also be used to determine the geological type; no specific limitation is made here.

[0029] In a preferred embodiment, determining the geological type of the construction area based on geological resistance parameters includes: If the geological resistance parameter is greater than or equal to the first preset resistance threshold, the geological type of the construction area is determined to be a hard rock section. If the geological resistance parameter is less than or equal to the second preset resistance threshold, the geological type of the construction area is determined to be a soft rock section; the second preset resistance threshold is less than the first preset resistance threshold. If the geological resistance parameter is less than the first preset resistance threshold and greater than the second preset resistance threshold, then the geological type of the construction area is determined to be a transitional geological section.

[0030] Specifically, if the geological resistance parameter is greater than or equal to the first preset resistance threshold, it indicates that the structure of the tunnel surrounding rock is stable, and the geological type of the construction area is determined to be a hard rock section. If the geological resistance parameter is less than or equal to the second preset resistance threshold, it indicates that the structure of the tunnel surrounding rock is loose, and the geological type of the construction area is determined to be a soft rock section. If the geological resistance parameter is less than the first preset resistance threshold but greater than the second preset resistance threshold, it indicates that the surrounding rock of the construction area has characteristics of both hard and soft rock, and the geological conditions are heterogeneous, and the geological type of the construction area is determined to be a transitional geological section (i.e., a mixed geological section between hard and soft rock sections). The first preset resistance threshold is a critical value suitable for determining the surrounding rock of hard rock sections. The second preset resistance threshold is a critical value suitable for determining the surrounding rock of soft rock sections. The second preset resistance threshold is less than the first preset resistance threshold. In this embodiment, based on the measured geological resistance parameters of common hard rock sections such as intact granite and tuff, the first preset resistance threshold is set to 1.2 MPa. Based on the measured geological resistance data of typical strongly weathered sandstone and conglomerate, fault breccia and other loose surrounding rocks in the soft rock section, the second preset resistance threshold is set to 0.5 MPa.

[0031] In a preferred embodiment, determining the dredging strategy based on the geological type of the construction area and the type of segments currently being dredged with gravel includes: The particle size distribution of the pea gravel used for dredging is determined based on the type of segments currently being dredged with pea gravel. The filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel.

[0032] Specifically, the dredging strategy includes the particle size distribution of the gravel used for dredging, the dredging pressure, and the dredging method. The particle size distribution of the gravel used for dredging is determined based on the type of tunnel segments currently being dredged. The dredging pressure and method are determined based on the geological type of the construction area and the type of tunnel segments currently being dredged. Different types of tunnel segments (bottom segments, side segments, and top segments) have different stress states and functional positioning in the tunnel lining ring, and the corresponding gravel particle size distribution must be adapted to their functional requirements to ensure the filling effect and the overall stability of the tunnel lining ring. Particle size distribution refers to the proportion of different particle sizes in the gravel used for dredging (i.e., the ratio of different sized gravel in the overall dredging material). The rationality of the particle size distribution directly determines whether the gravel can uniformly fill the gaps between the tunnel lining ring and the surrounding rock of the tunnel, and whether it can form a tight bond with the subsequently injected cement grout. A reasonable particle size distribution allows the gravel to fill the gaps and reduce voids.

[0033] In a preferred embodiment, determining the particle size distribution of the gravel used for dredging, based on the type of segments currently being dredged, includes: If the segment type currently being boulded with gravel is bottom segment, then the particle size distribution of the gravel used for boulding is determined to be the first particle size distribution. If the segment type currently being filled with gravel is a side segment, then the particle size distribution of the gravel used for filling the side segment is determined to be the second particle size distribution. If the type of pipe segment currently being filled with gravel is a jacking segment, then the particle size distribution of the gravel used for filling the jacking segment is determined to be the third particle size distribution. The proportion of gravel with a particle size larger than the preset particle size in the first particle size distribution is greater than that in the second particle size distribution, and the proportion of gravel with a particle size larger than the preset particle size in the second particle size distribution is greater than that in the third particle size distribution.

[0034] Specifically, when determining the particle size distribution of the gravel used for boulding based on the type of tunnel segment currently being boulded, if the segment type is a bottom segment, the particle size distribution is determined to be the first particle size distribution. If the segment type is a side segment, the particle size distribution is determined to be the second particle size distribution. If the segment type is a top segment, the particle size distribution is determined to be the third particle size distribution. In the first particle size distribution, the proportion of gravel with a particle size larger than a preset particle size is greater than that in the second particle size distribution; in the second particle size distribution, the proportion of gravel with a particle size larger than a preset particle size is greater than that in the third particle size distribution. For example, in this embodiment, 20mm, a commonly used particle size for tunnel gravel filling, is selected as the preset particle size. In the first particle size distribution, 60%~70% of the gravel has a particle size greater than 20mm, and the remainder is gravel with a particle size less than or equal to 20mm. In the second particle size distribution, 40%~50% of the gravel has a particle size greater than 20mm, and the remainder is gravel with a particle size less than or equal to 20mm. In the third particle size distribution, 20%~30% of the gravel has a particle size greater than 20mm, and the remainder is gravel with a particle size less than or equal to 20mm. The bottom segment, as the base support structure of the segment lining ring, needs to bear the vertical load of the upper surrounding rock of the tunnel, the segment, and the filling layer. A higher proportion of large-diameter gravel can improve the density and compressive bearing capacity of the filling layer and avoid base settlement. The side segments play the role of lateral support and gravel diversion. A medium proportion of large-diameter gravel can take into account both lateral stability and the smooth flow of gravel, preventing particle blockage during the dredging process. The filling area of ​​the tunnel jacking segment is affected by gravity, and the gravel is prone to sinking and forming cavities. The lower proportion of large-diameter gravel makes it easier for the gravel to overcome gravity and fill the gap between the tunnel jacking segment and the surrounding rock of the tunnel, effectively reducing filling defects such as top cavities and looseness.

[0035] In a preferred embodiment, the dredging pressure and dredging method are determined based on the geological type of the construction area and the type of segments currently being dredged with gravel, including: If the geological type of the construction area is hard rock, the filling pressure is determined to be the first preset range. The first preset range includes a first sub-range, a second sub-range, and a third sub-range. The lower boundary value of the first sub-range is greater than or equal to the upper boundary value of the third sub-range. The lower boundary value of the second sub-range is within the third sub-range, and the upper boundary value of the second sub-range is within the first sub-range. If the segment type currently being filled with gravel is a jacking segment, then the filling pressure of the jacking segment is determined to be the first sub-range, and the jacking segment is continuously filled according to the filling pressure within the first sub-range. If the segment type currently being backfilled with gravel is a bottom segment, then the backfilling pressure of the bottom segment is determined to be the second sub-range, and the bottom segment is continuously backfilled according to the backfilling pressure within the second sub-range. If the segment type currently being filled with gravel is a side segment, then the filling pressure of that side segment is determined to be the third sub-range, and the side segment is continuously filled according to the filling pressure within the third sub-range.

[0036] Specifically, if the geological type of the construction area is hard rock, the dredging pressure is determined to be within a first preset range. This first preset range is a dredging pressure range that satisfies the density requirements of gravel filling between the bottom, top, and side segments of the tunnel and the surrounding rock in the hard rock section, without causing damage to the surrounding rock due to the dredging pressure. The first preset range includes a first sub-range, a second sub-range, and a third sub-range. If the segment currently being dredged with gravel is a top segment, the dredging pressure for that top segment is determined to be within the first sub-range, and dredging is continuously performed on that top segment according to the dredging pressure within the first sub-range. If the segment currently being dredged with gravel is a bottom segment, the dredging pressure for that bottom segment is determined to be within the second sub-range, and dredging is continuously performed on that bottom segment according to the dredging pressure within the second sub-range. If the segment currently being dredged with gravel is a side segment, the dredging pressure for that side segment is determined to be within the third sub-range, and dredging is continuously performed on that side segment according to the dredging pressure within the third sub-range. The lower boundary value of the first sub-range is greater than or equal to the upper boundary value of the third sub-range, the lower boundary value of the second sub-range is within the third sub-range, and the upper boundary value of the second sub-range is within the first sub-range. For example, in this embodiment, considering the actual construction requirements of the hard rock section, the first preset range is set to 0.4~0.8MPa, the first sub-range is 0.6~0.8MPa, the second sub-range is 0.5~0.7MPa, and the third sub-range is 0.4~0.6MPa. During construction, the jacking segment can overcome the weight of the gravel itself with the continuous blowing force of the highest pressure, pushing the gravel to fully fill the space between the jacking segment and the tunnel surrounding rock, avoiding the problems of voids and loose filling that easily occur at the jacking segment in the hard rock section. The bottom segment, through a medium to high continuous pressure, ensures the density and bearing capacity of the gravel filling the space between the bottom segment and the tunnel surrounding rock. Side-segment filling is carried out with continuous blasting at the lowest pressure. This ensures the dense filling of the side gaps while avoiding lateral displacement and joint loosening caused by high pressure. It also improves the flow of gravel between the side-segments and the surrounding rock, preventing particle blockage of the filling path. Furthermore, the continuous blasting method is compatible with the stable geological characteristics of hard rock sections. The stable, unfluctuating blasting pressure allows the gravel to gradually compact during the compression process, avoiding stratification and uneven accumulation caused by sudden pressure changes, further improving the construction quality of gravel filling in hard rock sections.

[0037] In a preferred embodiment, the dredging pressure and dredging method are determined based on the geological type of the construction area and the type of segments currently being dredged with gravel, including: If the geological type of the construction area is soft rock, then the filling pressure is determined to be the second preset range; Pulse-type blowing is performed on the jacking segments, bottom segments, and side segments in the soft rock section according to the blowing pressure within the second preset range.

[0038] Specifically, if the geological type of the construction area is soft rock, the dredging pressure is determined to be within a second preset range. Pulse-type dredging is performed on the jacking segments, bottom segments, and side segments within the soft rock section according to the dredging pressure within the second preset range. The second preset range is a range of dredging pressure that provides sufficient pressure for gravel dredging while avoiding surrounding rock fracturing and borehole collapse in the soft rock section. For example, in this embodiment, considering the actual construction needs of the soft rock section, the second preset range is set to 0.3~0.5MPa. The pulse-type dredging refers to the alternating switching of the dredging pressure within the second preset range according to a preset pattern. That is, the dredging pressure is applied in stages to push the gravel, and then the pressure is reduced in stages to form a buffer period, allowing the loose soft rock to maintain structural stability during the buffer period and avoiding cumulative deformation or fracturing due to continuous stress.

[0039] In a preferred embodiment, the dredging pressure and dredging method are determined based on the geological type of the construction area and the type of segments currently being dredged with gravel, including: If the geological type of the construction area is a transitional geological section, then the dredging pressure is determined to be the third preset range; Linear adjustment caving is carried out on the jacking segments, bottom segments, and side segments in the transition geological section according to the caving pressure within the third preset range.

[0040] Specifically, if the geological type of the construction area is a transitional geological section, the dredging pressure is determined to be a third preset range. The jacking segments, bottom segments, and side segments within the transitional geological section are dredged using a linearly adjusted dredging pressure within this third preset range. The third preset range is a pressure range that provides sufficient dredging pressure to ensure the density of the gravel filling while also adapting to the uneven geological distribution of the transitional geological section, where some areas are dense and stable while others are loose and fragmented. For example, in this embodiment, considering the construction requirements of the transitional geological section, the third preset range is set to 0.5~0.7 MPa. The linearly adjusted dredging means that the dredging pressure is adjusted linearly proportionally to the changes in geological resistance parameters in different areas of the transitional geological section. This ensures that the dredging pressure is adapted to the uneven geological distribution of the transitional geological section, guaranteeing the density of the gravel filling in different local areas while avoiding disturbance to the surrounding rock in loose areas.

[0041] In a preferred embodiment, the method further includes: Obtain the gravel filling density between the segment lining ring and the tunnel surrounding rock after the bottom segment, side segment and top segment have been filled with gravel, and perform gravel supplementary filling at locations where the gravel filling density is less than the preset density threshold.

[0042] Specifically, the density of the gravel filling in the tunnel lining ring between the bottom, side, and top tunnel segments and the surrounding rock is tested by inserting probes into pre-drilled holes in the bottom, side, and top tunnel segments. For locations where the gravel filling density is lower than a preset density threshold, targeted gravel replenishment is performed to eliminate potential local voids and looseness after the entire gravel ring is filled, preventing insufficient density from affecting subsequent grouting. Density is a crucial indicator of the quality of gravel filling construction; a higher value indicates better gravel filling and superior subsequent grouting results. In this embodiment, the preset density threshold is 95%.

[0043] This invention optimizes the gravel filling sequence for honeycomb-arranged tunnel segment lining rings. It employs a filling sequence that first sequentially fills the bottom segments of adjacent target segment lining rings and the bottom segments of the ring to be filled, followed by the filling of the side and top segments of the target segment lining ring. This solves the technical problems of insufficient filling of side segment gaps, blocked filling paths for bottom segments, and incomplete compaction caused by the random sequence in existing filling methods. By determining the gravel particle size distribution, filling pressure, and filling method based on the geological type of the construction area and the type of segment being filled, it takes into account the filling requirements of different geological types and segment types, improving the construction quality of gravel filling and enhancing the reliability and stability of the tunnel segment lining ring.

[0044] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. The above are only preferred embodiments of the present invention. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other occasions without modification, should all be considered within the scope of protection of the present invention.

Claims

1. A method for filling tunnel segment lining rings with gravel, wherein multiple segment lining rings are coaxially arranged and sequentially arranged in a honeycomb pattern along their axial direction, each segment lining ring comprising a bottom segment, two side segments, and a top segment, characterized in that... The method includes: S1. Gravel filling is carried out between the bottom segment of the target segment lining ring and the surrounding rock of the tunnel; the target segment lining ring is the segment lining ring corresponding to the current construction position; S2. Gravel is blown into the space between the bottom segment of the lining ring to be blown in and the surrounding rock of the tunnel; the lining ring to be blown in is the next lining ring adjacent to the target lining ring. S3. If the number of lining rings filled with gravel between the bottom segment and the surrounding rock of the tunnel reaches the preset number, the side segments and top segments of the lining ring to be filled are removed from the shield tail of the tunnel boring machine, and then step S6 is executed; otherwise, steps S4-S5 are executed. S4. Gravel filling is carried out sequentially between the side segments of the target segment lining ring and the surrounding rock of the tunnel, and between the top segment of the target segment lining ring and the surrounding rock of the tunnel. S5. Take the lining ring of the segment to be filled as the target segment lining ring and execute steps S2-S3; S6. Grouting is carried out sequentially on the lining rings of the tunnel segments that have been filled with gravel between the bottom segments, side segments, and top segments and the surrounding rock of the tunnel.

2. The method for filling tunnel segment lining with pebbly gravel according to claim 1, characterized in that, The method further includes: Obtain the geological type of the construction area and the type of segments currently being filled with gravel; The filling strategy is determined based on the geological type of the construction area and the type of segments currently being filled with gravel.

3. The method for filling tunnel segment lining with pebbly gravel according to claim 2, characterized in that, The geological types of the construction area include: Obtain the geological resistance parameters of the surrounding rock of the tunnel in the construction area; The geological type of the construction area is determined based on the geological resistance parameters.

4. The method for filling tunnel segment lining with pebbly gravel according to claim 3, characterized in that, Determining the geological type of the construction area based on the aforementioned geological resistance parameters includes: If the geological resistance parameter is greater than or equal to the first preset resistance threshold, then the geological type of the construction area is determined to be a hard rock section. If the geological resistance parameter is less than or equal to the second preset resistance threshold, then the geological type of the construction area is determined to be a soft rock section; the second preset resistance threshold is less than the first preset resistance threshold. If the geological resistance parameter is less than the first preset resistance threshold and greater than the second preset resistance threshold, then the geological type of the construction area is determined to be a transitional geological section.

5. The method for filling tunnel segment lining with pebbly gravel according to claim 4, characterized in that, The dredging strategy is determined based on the geological type of the construction area and the type of segments currently being dredged with gravel, including: The particle size distribution of the pea gravel used for dredging is determined based on the type of segments currently being dredged with pea gravel. The filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel.

6. The method for filling tunnel segment lining with pebbly gravel according to claim 5, characterized in that, The particle size distribution of the gravel used for dredging is determined based on the type of segments currently being dredged using gravel, including: If the segment type currently being filled with pea gravel is a bottom segment, then the particle size distribution of the pea gravel used for filling is determined to be the first particle size distribution. If the segment type currently being filled with pea gravel is a side segment, then the particle size distribution of the pea gravel used for filling the side segment is determined to be the second particle size distribution. If the segment type currently being filled with gravel is a jacking segment, then the particle size distribution of the gravel used for filling the jacking segment is determined to be the third particle size distribution. The proportion of gravel with a particle size larger than the preset particle size in the first particle size distribution is greater than the proportion of gravel with a particle size larger than the preset particle size in the second particle size distribution, and the proportion of gravel with a particle size larger than the preset particle size in the second particle size distribution is greater than the proportion of gravel with a particle size larger than the preset particle size in the third particle size distribution.

7. The method for filling tunnel segment lining with pebbly gravel according to claim 5, characterized in that, The filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel, including: If the geological type of the construction area is hard rock, then the filling pressure is determined to be a first preset range; the first preset range includes a first sub-range, a second sub-range and a third sub-range, the lower boundary value of the first sub-range is greater than or equal to the upper boundary value of the third sub-range, the lower boundary value of the second sub-range is within the third sub-range, and the upper boundary value of the second sub-range is within the first sub-range; If the segment type currently undergoing gravel backfilling is a jacking segment, then the backfilling pressure of the jacking segment is determined to be the first sub-range, and the jacking segment is continuously backfilled according to the backfilling pressure within the first sub-range. If the segment type currently being filled with gravel is a bottom segment, then the filling pressure of the bottom segment is determined to be the second sub-range, and the bottom segment is continuously filled according to the filling pressure within the second sub-range. If the segment type currently being filled with gravel is a side segment, then the filling pressure of the side segment is determined to be the third sub-range, and the side segment is continuously filled according to the filling pressure within the third sub-range.

8. The method for filling tunnel segment lining with pebbly gravel according to claim 5, characterized in that, The filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel, including: If the geological type of the construction area is soft rock, then the filling pressure is determined to be the second preset range; The jacking segments, bottom segments, and side segments in the soft rock section are pulsed and filled with pressure within the second preset range.

9. The method for filling tunnel segment lining with pebbly gravel according to claim 5, characterized in that, The filling pressure and filling method are determined based on the geological type of the construction area and the type of segments currently being filled with gravel, including: If the geological type of the construction area is a transitional geological section, then the filling pressure is determined to be the third preset range; Linearly adjusted filling is carried out on the jacking segments, bottom segments, and side segments in the transition geological section according to the filling pressure within the third preset range.

10. The method for filling tunnel segment lining with pebbly gravel according to claim 1, characterized in that, The method further includes: Obtain the gravel filling density between the segment lining ring and the tunnel surrounding rock after the bottom segment, side segment and top segment have been filled with gravel, and perform gravel supplementary filling at locations where the gravel filling density is less than the preset density threshold.

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