Construction method of main tunnel hole of liaison channel

Abstract

The application discloses a construction method for a main tunnel hole of a liaison channel, and comprises the following steps: firstly, a grouting hole is arranged in the opening area of the main tunnel portal segment, the soil on the outer side is grouted and reinforced, and the soil strength and moisture content are detected in adjacent grouting holes to confirm the grouting effect; after the soil is determined to be stable and the water stop is completed, on the one hand, the annular cutting knife is used to cut the portal until the portal is completely cut through; on the other hand, the support arm is used to participate in the cutting operation throughout the process, after the portal cutting is completed, the rock-soil condition of the liaison channel portal is judged by the force condition of the sensor at the front end of the support arm combined with the geological report, and the posture of the portal cutting block cut down is adjusted by the support arm. The application realizes the integrated operation of the portal cutting construction from reinforcement to cutting to regulation, reduces the process connection time, and formulates a differentiated support arm operation strategy for different strata, so that the low efficiency or safety risk caused by the existing single grinding construction method is avoided.

Description

Technical Field

[0001] This invention belongs to the field of tunnel construction technology, specifically relating to a construction method for breaking through the main tunnel of a connecting passage. Background Technology

[0002] As a key auxiliary structure in tunnel engineering (especially urban subway tunnels and river-crossing tunnels), connecting passages mainly undertake core functions such as emergency evacuation, pipeline laying, and ventilation and smoke extraction. Their construction quality and efficiency directly affect the overall operational safety of the tunnel and the project construction cycle.

[0003] Traditional tunnel construction, especially at the portal breach where the main tunnel meets the connecting passage, requires repeated grinding of the concrete segments and surrounding soil and rock. On the one hand, the concrete grinding process is time-consuming and energy-intensive; large grinding equipment can operate for several days or even longer in a single session, and the equipment has high power consumption, resulting in significant energy loss. On the other hand, the large amount of debris generated during grinding requires frequent cleaning, further extending the process cycle and making it difficult to meet the "efficient advancement" construction requirements of modern tunnel engineering.

[0004] To address the risks of soil collapse and water seepage, traditional construction methods often involve soil reinforcement in advance. However, the reinforcement method is usually "integral grouting," which lacks coordinated design with subsequent cutting operations. On the one hand, the reinforcement range and strength are difficult to precisely match the cutting requirements, which may result in over-reinforcement leading to increased cutting resistance, or insufficient reinforcement still posing safety hazards. On the other hand, the reinforcement and cutting operations are carried out independently, with loose connections between the procedures, failing to form an integrated "reinforcement-cutting" process, further reducing construction efficiency.

[0005] With the increasing development of urban underground space and the continuous expansion of tunnel engineering, the industry is placing higher demands on the construction of connecting passages. This requires both reducing construction costs (including time, energy, and labor costs) and improving construction safety and stability to avoid economic losses and social impacts caused by construction accidents. Traditional construction methods are no longer sufficient to meet this core requirement, necessitating a new construction technology that can achieve "efficient cutting, precise reinforcement, geological adaptation, and safety and energy saving." Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a construction method for breaking through the main tunnel of a connecting passage, so as to solve the problems of long construction period for breaking through the main tunnel of a connecting passage and lack of coordinated design of soil reinforcement and subsequent cutting operations.

[0007] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0008] A construction method for breaching the main tunnel of a connecting passage includes the following construction steps:

[0009] S1. Several grouting holes are opened in the opening area of ​​the main tunnel portal segment, and the grouting holes are evenly distributed along the edge of the opening area; grout is injected into the soil outside the main tunnel through the grouting holes, and the soil strength and moisture content are tested at adjacent grouting holes to confirm the grouting effect.

[0010] S2. After confirming that the soil outside the tunnel portal has formed a stable whole and achieved the water-stopping effect, use the ring-shaped cutting blade of the cutter head device to make a ring-shaped cut on the tunnel portal inside the ring steel plate until the tunnel portal is completely cut through.

[0011] S3. Before the tunnel portal is cut, the multi-section telescopic support arm of the hydraulic support arm is connected to the connection point on the segment to be cut inside the annular steel plate to form a support. After the tunnel portal is cut, the rock and soil conditions at the entrance of the connecting passage are judged by the force condition of the sensor at the front end of the support arm combined with the geological report. The posture of the cut tunnel portal segment is adjusted by the support arm.

[0012] Furthermore, the method includes the following steps: Before opening the grouting hole in step S1, during the main tunnel advancement stage, a portal segment with a pre-embedded annular steel plate is installed at the portal location of the connecting passage, so that the area where the pre-embedded annular steel plate is located forms the junction of the main tunnel and the connecting passage, and the hollow area inside the annular steel plate forms the opening area. Regarding the concrete segments within the opening area, during segment prefabrication, a lower grade of glass fiber reinforced concrete is used within the opening area according to design requirements.

[0013] Furthermore, during the construction process of step S1, when grouting is carried out into the soil outside the main tunnel through the grouting hole, the insertion depth of the grouting pipe is controlled to be 1 meter.

[0014] Furthermore, during the construction process in step S1, when grouting is carried out into the soil outside the main tunnel through the grouting hole, it is ensured that there is no flowing water in the soil after grouting and that the soil reaches a certain strength.

[0015] Furthermore, during the construction process of step S1, if it is confirmed that the grouting reinforcement effect does not meet expectations, the grouting density is gradually increased according to actual needs.

[0016] Furthermore, during the construction process in step S3, when it is determined that the soil and rock conditions at the entrance of the connecting passage after reinforcement are hard soil and rock layers, the support arm is directly retracted, and the planar cutter head is used to continue advancing to grind the cut segments and soil together until the passage size requirements are met.

[0017] Furthermore, during the construction process of step S3, when it is determined that the soil and rock conditions at the entrance of the connecting passage after reinforcement are relatively soft soil layers, after the cut-off segments and cutterhead have completely exited the tunnel, the support arm is first used to push the cut-off segments into the soil layer, and the posture of the tunnel entrance cutting blocks is controlled to ensure that they avoid the subsequent travel route of the equipment. After the equipment position is stable, the support arm is then retracted.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] This invention uses grouting to stabilize the soil in the construction area, achieving a water-stopping effect and providing a safe environment for subsequent cutting operations. The pre-drilling of grouting holes directly reduces the resistance of ring cutting, improving its efficiency. By connecting the support arm to the segment to be cut, the support arm participates in the entire cutting process, resisting the reaction force of external rock and soil during the cutting of the main tunnel segment, reducing equipment vibration, and ensuring cutting accuracy and stability. After cutting through the tunnel portal, the soil properties are assessed, and the posture of the cut portal segments is adjusted using the front structure of the support arm. This achieves integrated operation of portal cutting from reinforcement to cutting to control, reducing process connection time. Furthermore, differentiated support arm operation strategies are developed for different strata (hard rock, soft soil), avoiding inefficiency or safety risks caused by a single construction method.

[0020] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0021] In the following description of the embodiments of the present invention, it should be understood that the orientation or positional relationship indicated by the present invention is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the purpose of facilitating the description of the present invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0022] In the embodiments of the present invention below, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances. Attached Figure Description

[0023] Figure 1 This is a diagram showing the location of the annular steel plate, grouting holes, and support points during the hole-breaking construction of this invention.

[0024] Figure 2 This is a construction state diagram of the hole-breaking process during the cutting of the hole entrance in the present invention;

[0025] Figure 3 This is a construction state diagram showing the support arm adjusting the cutting posture of the tunnel entrance during the hole-breaking construction process of the present invention.

[0026] The labels and their corresponding names in the diagram are as follows:

[0027] 1. Main tunnel segments, 2. Portal segments, 21. Annular steel plate,

[0028] 22. Opening area, 23. Grouting hole, 24. Densified grouting hole,

[0029] 25. Connection point; 26. Portal cutting block; 3. Cutter head assembly;

[0030] 31. Circular cutting blade; 32. Flat cutting disc blade; 4. Hydraulic support arm device.

[0031] 41. Support arm. Detailed Implementation

[0032] A construction method for breaching the main tunnel of a connecting passage, the method comprising the following construction steps:

[0033] S0. During the main tunnel advancement phase, such as Figure 1 As shown, a portal segment 2 with a pre-embedded annular steel plate 21 is installed at the portal location of the connecting passage, making the area where the pre-embedded annular steel plate 21 is located the junction of the main tunnel and the connecting passage. The hollow area inside the annular steel plate 21 forms the opening area 22. Regarding the concrete segment structure within the opening area 22, during segment prefabrication, a lower grade (lower grade here compared to the concrete grade used in the non-portal segments of the main tunnel (i.e., main tunnel segment 1) of glass fiber reinforced concrete is used in the opening area 22 according to design requirements. Using lower grade glass fiber reinforced concrete in the opening area 22 facilitates cutting by the cutter head device 3, reduces damage to the annular cutting blade 31 and the flat blade, and improves the cutting efficiency of the portal segment 2.

[0034] S1. Before the formal cutting of the portal segment 2, several grouting holes 23 are first opened in the opening area 22 of the main tunnel portal segment 2, and the grouting holes 23 are evenly distributed along the inner edge of the opening area 22 (i.e., close to the inner sidewall of the annular steel plate 21). Then, grout is injected into the soil outside the main tunnel through the grouting holes 23, and the soil strength is tested by micro-probe and the moisture content is tested by TDR probe at adjacent grouting holes 23 to confirm the grouting effect, ensuring that there is no flowing water in the soil after grouting and that the soil reaches a certain strength. If the grouting reinforcement effect is not as expected, additional grouting holes 24 can be added according to actual needs to gradually increase the density of grouting. Preferably, when grouting into the soil outside the main tunnel, a sleeve valve pipe / dual-liquid grout is used for grouting to improve the flexibility of grouting position control. The insertion depth of the grouting pipe is controlled to be about 1 meter, and the soil strength reaches 0.5 to 2 MPa.

[0035] This invention utilizes a reinforcement method of "grouting through holes drilled on the inner side of a ring-shaped steel plate + on-demand densification" to create a tight and stable integral structure in the soil of the construction area outside the main tunnel, effectively avoiding the risk of collapse of loose soil. Simultaneously, the grouting process fills the gaps between the rock and soil, achieving a reliable water-stopping effect and solving problems such as water accumulation and soil softening caused by seepage in traditional construction. This provides a dry and stable working environment for subsequent cutting and equipment advancement, ensuring a safe foundation for construction. By uniformly opening grouting holes along the edge of the opening area, the surrounding soil is reinforced, breaking the original structural strength of the concrete. Simultaneously, it can be used in conjunction with subsequent ring cutter cutting, significantly reducing cutting resistance compared to traditional direct mechanical cutting, significantly improving the efficiency of ring cutting and tunnel portal breaking, shortening the tunnel portal opening cycle, and increasing overall efficiency.

[0036] S2. After confirming that the soil outside the tunnel portal forms a stable whole and achieves a water-stopping effect, such as Figure 2 As shown, the cutter head device 3 with annular cutting blade 31, the hydraulic support arm device 4, the combined track, the jacking support device, the bottom support device and other auxiliary equipment are used to make annular cutting of the portal on the inner side of the annular steel plate 21 by the annular cutting blade 31 of the cutter head device 3 until the portal is completely cut through, thus opening the preliminary passage between the main tunnel and the connecting passage.

[0037] It should be noted that before the annular cutting blade 31 cuts the tunnel portal, a temporary seal must be formed by sealing the annular steel plate 21 on the tunnel portal segment 2 with a steel sleeve. This seal is convenient to close in case of an emergency during the segment opening process, so as to ensure the safety of the main tunnel construction.

[0038] S3. Before cutting the tunnel portal, connect the support arm 41 of the hydraulic support arm device 4 to the connection point 25 on the segment to be cut within the annular steel plate 21 to form a support. The support arm 41 is a multi-section telescopic rod, with one end hinged to the main body of the equipment via a support point, and the other end extending to the segment or soil area, connected to the connection point 25 on the segment via magnetic attraction; the entire unit extends and retracts along the track direction to adapt to different working positions. The power source of the hydraulic support arm device 4 is the extension, retraction, and swing of the support arm 41 driven by a hydraulic cylinder, and it also integrates a pressure sensor (with force detection function), and the data is synchronously fed back to the equipment's control system.

[0039] The support arm 41 participates in the entire cutting operation. When cutting the main tunnel portal segment 2, it mainly resists the reaction force of the external rock and soil, reduces equipment vibration, and ensures cutting accuracy and stability. After the portal cutting is completed, the force condition of the connecting passage portal entrance is determined by combining the sensor at the front end of the support arm 41 with the geological report. The posture of the cut portal segment 26 is then adjusted by the support arm 41. Specifically, when the unconfined compressive strength after reinforcement is detected to be ≥10MPa, it can be determined that the rock and soil condition of the connecting passage portal entrance after reinforcement is a hard rock and soil layer. At this time, the support arm 41 is directly retracted, and the planar cutter head 32 continues to advance, grinding the cut segments and soil together until the passage size requirements are met. Figure 3 As shown, when the unconfined compressive strength after reinforcement is detected to be ≤10MPa, it is determined that the soil and rock conditions at the entrance of the connecting passage after reinforcement are relatively soft soil layers. At this time, after the cut-off segments (i.e., the portal cutter block 26) and the cutter head have completely exited the tunnel, the support arm 41 is first used to push the cut-off segments into the soil layer. At the same time, the stress situation is analyzed. Then, the posture of the portal cutter block 26 is controlled to push the portal cutter block out from below or from the left and right sides to ensure that it avoids the subsequent travel path of the equipment. After the equipment position is stable, the support arm 41 is retracted.

[0040] During the cutting process, the support arm of this invention resists external reaction forces in real time, reduces equipment vibration, prevents cutter head deviation, ensures that the tunnel portal cutting contour conforms to the design dimensions, reduces subsequent trimming processes, and guarantees tunnel portal cutting accuracy. Furthermore, this invention can be precisely adapted to different geological strata to cope with complex geological scenarios. In hard rock strata, the cutter head can be ground after the support arm is retracted to ensure the excavation dimensions of the tunnel are maintained; in softer soil strata, the support arm is pushed into the soil to avoid the equipment's path, preventing equipment obstruction and controlling the breaking of concrete blocks through attitude control to prevent block collapse and blockage of the tunnel. This invention adapts to various common underground rock and soil scenarios, reducing the impact of geological differences on construction.

[0041] In summary, compared to traditional technologies, this invention addresses the risks of soil collapse and water seepage at the source through early-stage grouting reinforcement; the mid-stage vibration-resistant support arm ensures equipment stability during the cutting process, preventing segment damage and equipment failure caused by vibration; and the late-stage support arm controls the posture of the broken tunnel portal blocks, preventing them from falling or blocking the passage, forming a triple safety control system—before, during, and after the process—reducing construction safety hazards. It achieves integrated operation of tunnel portal cutting from reinforcement to cutting to control, reducing waiting time between processes. Furthermore, it allows for differentiated support arm operation strategies for different geological formations (hard rock, soft soil), avoiding inefficiency or safety risks caused by a single grinding method, and also avoiding efficiency losses due to frequent equipment switching, thus improving construction continuity.

[0042] This invention is not limited to the specific embodiments described above. For those skilled in the art, all modifications made based on the above concept without creative effort fall within the protection scope of this invention.

Claims

1. A construction method for breaking through the main tunnel of a connecting passage, characterized in that, The construction steps include the following: S1. Several grouting holes are opened in the opening area of ​​the main tunnel portal segment, and the grouting holes are evenly distributed along the edge of the opening area; grout is injected into the soil outside the main tunnel through the grouting holes, and the soil strength and moisture content are tested at adjacent grouting holes to confirm the grouting effect. S2. After confirming that the soil outside the tunnel portal has formed a stable whole and achieved the water-stopping effect, use the ring-shaped cutting blade of the cutter head device to make a ring-shaped cut on the tunnel portal inside the ring steel plate until the tunnel portal is completely cut through. S3. Before the tunnel portal is cut, the multi-section telescopic support arm of the hydraulic support arm is connected to the connection point on the segment to be cut inside the annular steel plate to form a support; after the tunnel portal is cut, the rock and soil conditions at the entrance of the connecting passage are judged by the force condition of the sensor at the front end of the support arm combined with the geological report, and the posture of the tunnel portal cutting block is adjusted by the support arm. During the construction process in step S3, when it is determined that the soil and rock conditions at the entrance of the connecting passage after reinforcement are hard soil and rock layers, the support arm is directly retracted and the planar cutter head is used to continue to advance, and the cut segments and soil are ground together until the passage size requirements are met. During the construction process in step S3, when it is determined that the soil and rock conditions at the entrance of the connecting passage after reinforcement are relatively soft soil layers, after the cut segments and cutterhead have completely exited the tunnel, the support arm is first used to push the cut segments into the soil layer, and the posture of the tunnel entrance cutting blocks is controlled to ensure that they avoid the subsequent travel path of the equipment. After the equipment position is stable, the support arm is then retracted.

2. The construction method for breaking through the main tunnel of a connecting passage according to claim 1, characterized in that, It also includes the following steps: Before opening the grouting hole in step S1, during the main tunnel advancement stage, a portal segment with a pre-embedded annular steel plate is installed at the portal of the connecting passage, so that the part of the pre-embedded annular steel plate forms the junction of the main tunnel and the connecting passage, and the hollow area inside the annular steel plate forms the opening area.

3. The construction method for breaking through the main tunnel of a connecting passage according to claim 2, characterized in that, During the main tunnel advancement phase, for the portal segments involving opening areas, lower grade glass fiber reinforced concrete shall be used in the opening areas during segment prefabrication, in accordance with design requirements.

4. The construction method for breaking through the main tunnel of a connecting passage according to claim 1, characterized in that, During the construction process in step S1, when grouting is carried out into the soil outside the main tunnel through the grouting hole, the insertion depth of the grouting pipe is controlled to be 1 meter.

5. The construction method for breaking through the main tunnel of a connecting passage according to claim 1, characterized in that, During the construction process in step S1, when grouting is carried out into the soil outside the main tunnel through the grouting hole, it is ensured that there is no flowing water in the soil after grouting and that the soil reaches a certain strength.

6. The construction method for breaking through the main tunnel of a connecting passage according to claim 1, characterized in that, During the construction process in step S1, if it is confirmed that the grouting reinforcement effect does not meet expectations, the grouting density will be gradually increased according to actual needs.

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