A non-dewatering construction method for underground excavation of a subway station near a spring lake

Abstract

The application discloses a non-dewatering construction method for underground excavation construction of a subway station near a spring lake, and relates to the technical field of subway station construction. The application discloses a non-dewatering construction method for underground excavation construction of a subway station near a spring lake, and relates to the technical field of subway station construction. The first drainage hole is connected to the dewatering well through a drainage pipe, and the first grouting hole is divided into a first sequence odd hole and a first sequence even hole according to the distribution position. When the first grouting hole is grouted, the first sequence odd hole and the first sequence even hole are sequentially grouted according to the sequence of the first sequence odd hole and the first sequence even hole. The first sequence even hole and the first drainage hole can drain the water in the section to the dewatering well, and then the original water is recharged into the soil at the construction position by the recharge well. The method can realize non-dewatering operation in the underground excavation construction of the subway station near the spring lake, and effectively reduces the disturbance of the construction to the surrounding underground water environment.

Description

Technical Field

[0001] This application generally relates to the field of subway station construction technology, and specifically to a method for non-dewatering construction of the underground tunnel near Quanhu subway station. Background Technology

[0002] Currently, the excavation of underground earthwork in subway station construction mainly uses two methods: open excavation and PBA (Precast Batteries and Pit) excavation. Due to urban development, the existing buildings around subway stations are relatively concentrated, surface traffic flow is high, underground pipelines are complex, coordination and relocation are difficult, and construction periods are long, the PBA excavation method is increasingly being used.

[0003] When subway stations are buried at considerable depths, the PBA (Pre-Construction Absorption Regulator) method for cut-and-cover construction typically requires temporary dewatering measures to lower the groundwater level below the working face. When subway stations are located near water-rich areas such as lakes, the cut-and-cover construction of subway stations inherently involves high risks and numerous hazards. The requirement to avoid dewatering further exacerbates the difficulty and increases the risk significantly. To ensure the safety of cut-and-cover construction, a method for preventing dewatering and protecting springs near springs or lakes is needed. This method integrates water-stopping, water-intercepting, and waterproofing to solve the problem of dewatering in urban subway station cut-and-cover construction. Summary of the Invention

[0004] In view of the above-mentioned defects or deficiencies in the existing technology, it is desirable to provide a method for tunneling near Quanhu Metro Station without dewatering.

[0005] This application provides a method for non-dewatering construction of cut-and-cover tunnels near Quanhu Metro Station, including:

[0006] According to the station construction requirements, the full-section deep hole grouting range of the cross passage was marked, and the full-section grouting outline was confirmed based on the grouting range; several first grouting holes and first drainage holes were arranged sequentially inside and outside the grouting outline.

[0007] The first drainage hole is connected to the dewatering well through a drainage pipe, and all the first grouting holes are divided into first-order odd-numbered holes and first-order even-numbered holes according to their distribution positions; the first-order odd-numbered holes and the first-order even-numbered holes are arranged at intervals in the first direction;

[0008] When grouting the first grouting hole, firstly, all the first sequential odd-numbered holes are grouted in stages. At this time, both the first sequential even-numbered holes and the first drainage hole can discharge the cross-sectional water outflow into the corresponding dewatering well. Then, the first sequential even-numbered holes are grouted in stages. At this time, the first drainage hole can discharge the cross-sectional water outflow into the corresponding dewatering well.

[0009] The raw water collected in the dewatering well is pumped into the recharge well, and the raw water is then recharged into the soil at the construction site.

[0010] According to the technical solution provided in this application, several first grouting holes are arranged in layers from top to bottom within the grouting outline, following its trend; all first grouting holes are divided into first-order odd-numbered holes and first-order even-numbered holes according to their distribution positions, including:

[0011] Each of the first grouting holes is divided into first-order odd-numbered holes and first-order even-numbered holes according to the parity of its position number in the layer, and each of the first grouting holes in each layer is of the same type as the first grouting holes above and below it after being divided.

[0012] According to the technical solution provided in this application, when grouting the first grouting hole, firstly, all the first sequential odd-numbered holes are grouted in stages. At this time, both the first sequential even-numbered holes and the first drainage hole can discharge the cross-sectional water outflow into the corresponding dewatering well; then, the first sequential even-numbered holes are grouted in stages. At this time, the first drainage hole can discharge the cross-sectional water outflow into the corresponding dewatering well, including:

[0013] A first steel pipe of a predetermined length is driven into the first grouting hole and the first drainage hole;

[0014] A single grouting is performed on the first steel pipe at the odd-numbered holes in the first sequence, at which time the first steel pipe at the even-numbered holes in the first sequence is connected to the drainage pipe; the grouting length of the single grouting is the construction length of the entire cross section of the transverse channel;

[0015] Monitor the grouting pressure, and when the grouting pressure reaches the designed final hole pressure, or when the grouting volume has reached the preset grouting volume, pull back one section of the first steel pipe and continue grouting until the first steel pipe is completely pulled back.

[0016] Disconnect the first steel pipe at the first even-numbered hole in the first sequence from the drainage pipe, and repeat the above steps to grout the first grouting hole at the first even-numbered hole in the first sequence.

[0017] According to the technical solution provided in this application, the method further includes:

[0018] After the grouting result of the first grouting hole is found to be qualified, the construction of the horizontal channel pipe shed will proceed.

[0019] The construction of the transverse passage pipe shed includes:

[0020] According to the preset specifications for the transverse passage pipe shed, perforated pipes and solid pipes are arranged at intervals to construct the transverse passage pipe shed; wherein, the perforated pipes are used for grouting, and the solid pipes are used for internal cement grout backfilling, and perforated pipes are set at the centerline of the transverse passage pipe shed.

[0021] When grouting into the perforated pipe, open the vent valve at the orifice of the perforated pipe, and stop grouting when grout is detected flowing out of the vent valve;

[0022] When backfilling with cement grout into the solid pipe, if leakage of grout is detected at the valve on the outside of the transverse channel pipe shed, the valve is closed and cement grout injection continues until the cement grout injection pressure is greater than the preset pressure value and remains at the preset time period, or when grout appears on the wall of the transverse channel pipe shed and the amount of cement grout injected is greater than the preset injection value, then cement grout injection is stopped.

[0023] According to the technical solution provided in this application, the method further includes:

[0024] After the construction of the transverse tunnel pipe shed is completed, the transverse tunnel is excavated based on the support of the transverse tunnel pipe shed, and after the excavation of the transverse tunnel is completed, the longitudinal guide tunnel is constructed.

[0025] The excavated transverse passage includes:

[0026] The initial support for the cross passage excavation is constructed. The initial support is equipped with an arch top and sides according to construction requirements, and the arch top and sides of the initial support are equipped with compensating grouting pipes.

[0027] When the initial support reaches the first preset height, or when the cross passage is excavated to the distance from the working face at the top of the arch to the first preset height, the initial support and the external soil layer are backfilled and grouted through the compensation grouting pipe.

[0028] According to the technical solution provided in this application, the construction of a longitudinal pilot tunnel includes:

[0029] The full-section deep hole grouting range of the longitudinal guide tunnel is calibrated, and the grouting outline of the longitudinal guide tunnel section is confirmed based on the grouting range of the longitudinal guide tunnel. Second grouting holes and second drainage holes are respectively opened inside and outside the grouting outline of the longitudinal guide tunnel section. The second grouting holes are divided into second-order odd holes and second-order even holes according to the first-order odd hole and the first-order even hole division method.

[0030] A second steel pipe is driven into the second drainage hole. The second steel pipes connected to the second drainage holes on both sides of the longitudinal guide tunnel are respectively connected to the dewatering well and the junction of the underground section and the open-cut section of the station. The second steel pipe connected to the junction can discharge the water from the cross section of the longitudinal guide tunnel into the dewatering well of the open-cut foundation pit.

[0031] A second steel pipe is driven into the second grouting hole, and the longitudinal guide tunnel is grouted in the order of first grouting the odd-numbered holes and then grouting the even-numbered holes.

[0032] According to the technical solution provided in this application, after completing the full-section grouting of the longitudinal guide tunnel, the method further includes:

[0033] After the grouting of the entire longitudinal guide tunnel is qualified, the construction of the longitudinal guide tunnel pipe shed and the excavation of the longitudinal guide tunnel are carried out in sequence.

[0034] According to the technical solution provided in this application, after the longitudinal pilot tunnel is excavated, the method further includes:

[0035] According to the station construction requirements, the distribution of each side pile in the longitudinal guide tunnel was obtained by surveying and setting out, and steel pipe piles were driven based on the obtained side pile positions.

[0036] At least one side pile grouting pipe is installed between every two adjacent steel pipe piles; the side pile grouting pipe is filled with grout, and all the side pile grouting pipes and the steel pipe piles are used together to form a water-stop curtain inside the tunnel.

[0037] According to the technical solution provided in this application, the center-to-center distance between each first grouting hole and between each second grouting hole is less than a preset distance; and there is mutual interlocking between two adjacent first grouting holes and two adjacent second grouting holes based on the set grouting pipe injection radius.

[0038] In summary, this technical solution specifically discloses a method for non-dewatering construction of the tunnel near Quanhu Metro Station. The method includes: marking the full-section deep-hole grouting range of the cross passage according to station construction requirements, and confirming the full-section grouting outline based on the grouting range; several first grouting holes and first drainage holes are arranged sequentially inside and outside the grouting outline; the first drainage holes are connected to dewatering wells via drainage pipes; all first grouting holes are divided into first-order odd-numbered holes and first-order even-numbered holes according to their distribution location; the first-order odd-numbered holes and first-order even-numbered holes are arranged alternately in the first direction; when grouting the first grouting holes, firstly, all first-order odd-numbered holes are graded for grouting, at which time both the first-order even-numbered holes and the first drainage holes can discharge the cross-section water to the corresponding dewatering well; then, the first-order even-numbered holes are graded for grouting, at which time the first drainage holes can discharge the cross-section water to the corresponding dewatering well; the original water collected in the dewatering wells is pumped into a recharge well, and the original water is recharged into the soil at the construction location by the recharge well.

[0039] When subway stations are located near water-rich areas such as lakes, the underground excavation of subway stations is characterized by high risks and numerous hazards. Furthermore, the dewatering operations implemented during construction can easily lead to environmental problems such as ground subsidence and soil consolidation. This application's technical solution addresses these issues by defining the full-section deep-hole grouting range of the transverse passage and delineating the grouting outline. First grouting holes and first drainage holes are sequentially arranged inside and around the grouting area. A step-by-step grouting method is employed, draining the water from the grouting section into a dewatering well, which is then reinjected into the soil at the construction site through a recharge well. This method enables dewatering-free operation during the underground excavation of the Quanhu subway station, effectively controlling water seepage at the grouting section, reducing disturbance to the surrounding groundwater environment, ensuring grouting effectiveness and construction stability, and balancing construction efficiency with the protection of the surrounding soil and environment. Attached Figure Description

[0040] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0041] Figure 1 This is a flowchart illustrating steps S100-S400 of a method for non-dewatering construction of a tunnel near Quanhu Metro Station.

[0042] Figure 2 This is a flowchart illustrating step S300 in the construction method of the present invention.

[0043] Figure 3 This is a flowchart illustrating steps S500-S700 in the construction method of the present invention.

[0044] Figure 4 This is a flowchart illustrating steps S800-S900 in the construction method of the present invention.

[0045] Figure 5 A flowchart illustrating steps S110-S310 in the construction method of the present invention.

[0046] Figure 6 This is a schematic diagram of the full-section layout of the cross passage in the construction method of the present invention.

[0047] Figure 7 This is an enlarged schematic diagram of the full cross-section A of the transverse passage in the construction method of the present invention.

[0048] Figure 8 This is a schematic diagram showing the locations of the dewatering wells and recharge wells in the construction method of the present invention.

[0049] Figure 9 This is a schematic diagram of the initial support grouting behind the cross passage in the construction method of the present invention.

[0050] Figure 10 This is a schematic diagram of the full-section layout of the longitudinal guide tunnel in the construction method of the present invention.

[0051] Figure 11 This is a schematic diagram of the initial support back grouting in the construction method of the present invention for the longitudinal guide tunnel.

[0052] Figure 12 This is a schematic diagram showing the position of the steel pipe pile in the longitudinal pilot tunnel in the construction method of the present invention.

[0053] Figure 13 This is a schematic diagram showing the installation positions of steel pipe piles and grouting pipes in the longitudinal guide tunnel in the construction method of the present invention.

[0054] Numbered in the diagram: 1. Horizontal tunnel pipe shed; 2. Longitudinal guide tunnel pipe shed construction; 3. Grouting outline; 4. First drainage hole; 5. Second drainage hole; 6. First sequence odd-numbered hole; 7. First sequence even-numbered hole; 8. Second sequence odd-numbered hole; 9. Second sequence even-numbered hole; 10. Recharge well; 101. First recharge well; 102. Second recharge well; 103. Third recharge well; 104. Fourth recharge well; 105. Fifth recharge well; 106. Sixth recharge well; 107. Seventh recharge well; 108. Eighth recharge well; 109. Ninth recharge well; 1010. Tenth recharge well; 1011. Eleventh recharge well; 012, Twelfth injection well; 1013, Thirteenth injection well; 1014, Fourteenth injection well; 1015, Fifteenth injection well; 1016, Sixteenth injection well; 1017, Seventeenth injection well; 11, Dewatering well; 111, First dewatering well; 112, Second dewatering well; 113, Third dewatering well; 114, Fourth dewatering well; 115, Fifth dewatering well; 116, Sixth dewatering well; 117, Seventh dewatering well; 118, Eighth dewatering well; 119, Ninth dewatering well; 1110, Tenth dewatering well; 12, Initial support; 13, Compensation grouting pipe; 14, Steel pipe pile; 15, Side pile grouting pipe. Detailed Implementation

[0055] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0057] Example 1

[0058] When constructing existing deep-buried subway stations in water-rich areas, the construction faces challenges due to factors such as concentrated existing buildings around the stations, high surface traffic volume, complex underground pipelines, difficulties in coordination and relocation, and long construction periods. Therefore, the cut-and-cover (PBA) method is more commonly used in both open-cut and tunnel-to-ground (CTO) PBA methods. However, the CTO PBA method generally requires temporary dewatering, which can cause a drop in spring and lake water levels, impacting natural scenic areas. Conversely, construction without dewatering carries significant risks.

[0059] Please refer to Figure 1 The illustrated embodiment provides a flowchart of a method for non-dewatering construction of the tunnel near Quanhu Metro Station. Figure 1 as well as Figures 6-12The structural diagram shown illustrates a systematic construction method that integrates water-stopping, water interception, and waterproofing. This method effectively solves the problem of underground excavation without dewatering in subway stations located near water-rich areas, demonstrating high practical value. Specifically, the method includes:

[0060] S100. According to the station construction requirements, mark the full-section deep hole grouting range of the cross passage, and confirm the full-section grouting outline 3 based on the grouting range; several first grouting holes and first drainage holes 4 are arranged sequentially inside and outside the grouting outline 3.

[0061] In the specific construction method, before the full-section deep hole grouting range of the transverse passage is marked, the following steps are also included: vertical shaft excavation construction; vertical shaft excavation construction is a preliminary process for transverse passage construction, creating conditions for subsequent transverse passage construction. Its steps usually include measurement, trench excavation, wellhead ring, etc., which will not be elaborated here.

[0062] After the vertical shaft excavation is completed, full-section grouting of the horizontal passage is carried out. The determination of the full-section deep-hole grouting range of the horizontal passage is based on the geological conditions, construction safety, and design requirements of the construction site. The full-section deep-hole grouting range of the horizontal passage refers to the surrounding rock area that needs to be reinforced and waterproofed by grouting. Its core purpose is to include the surrounding rock that may be unstable or seeping at the excavation face of the horizontal passage within the grouting treatment range, forming a "safety protection zone". The scope of this "safety protection zone" is defined by the grouting outline line 3. For details, please refer to [reference needed]. Figure 6 Marked location.

[0063] As a key passage connecting the vertical shaft and the main structure, the horizontal passage needs to be pre-reinforced and waterproofed before excavation to ensure overall construction safety and efficiency. Therefore, after defining the grouting outline 3, the distribution positions of the first grouting hole and the first drainage hole 4 can be set based on the grouting outline 3. The first grouting hole is a grout injection channel. The grout (in this embodiment, the grout is selected as a two-component grout with a strong waterproofing effect of not less than P.O42.5, consisting of ordinary silicate cement and water glass) is injected into the stratum under high pressure to fill the gaps between soil particles, cement the loose soil, improve the stratum strength, and block the groundwater seepage channels to achieve the waterproofing effect. The first drainage hole 4 is used to drain the original groundwater or water generated by grout dilution in the stratum before or during grouting, thereby reducing the water pressure in the stratum.

[0064] It should be noted that after the positions of each first grouting hole and first drainage hole 4 are determined by measurement, horizontal directional drilling using a water-jet drilling rig is required to drill through the diaphragm wall. Drilling should generally adhere to the following principle: the distance between the center of each first grouting hole should be less than a preset distance (e.g., 1000mm). Furthermore, the injection radius of the grouting pipe should be no less than 650mm to ensure a certain degree of interlocking between adjacent first grouting holes, allowing the grout to spread evenly in the soil layer based on the injection radius. In addition, after drilling, a hole opening pipe and a sealing plug must be installed at the hole opening. Plates and ball valves; In actual construction operations, the first grouting hole and the first drainage hole 4 are drilled using a multi-functional drilling machine. Hollow drill rods are used. The drilling machine is positioned according to the designated location, and under the guidance of technicians, the angle of the drill rod is adjusted. After aligning with the hole position, the drilling machine must not move. In this embodiment, a more stable and precise segmented drilling method is adopted. Theoretically, the length of each segment is set to no more than 1.5m (this value is not specifically limited). A double-hole special connector and a special drill bit are used to drill between adjacent segments, so that segmented drilling can be carried out stably.

[0065] S200. Connect the first drainage hole 4 to the dewatering well 11 through a drainage pipe. Divide all the first grouting holes into first-order odd-numbered holes 6 and first-order even-numbered holes 7 according to their distribution positions. The first-order odd-numbered holes 6 and the first-order even-numbered holes 7 are arranged at intervals in the first direction.

[0066] Combined Figure 6 As shown, several first grouting holes are arranged in layers from top to bottom within the grouting contour line 3, following its direction. Therefore, the first direction here follows the direction of the grouting contour line 3 from the left end to the right end. Ultimately, the first grouting holes are evenly and densely arranged within the grouting contour line 3, so that the entire cross-section deep hole grouting range of the transverse channel can be covered when grouting is performed through each first grouting hole. Next, the specific division of the first sequence odd-numbered holes 6 and the first sequence even-numbered holes 7 in step S200 is as follows:

[0067] Each first grouting hole is divided into first-order odd-numbered holes 6 and first-order even-numbered holes 7 according to the parity of its position number in the layer, and the first grouting holes in each layer are of the same type as the first grouting holes above and below.

[0068] Taking the first grouting hole near the top of the grouting outline 3 as the first layer of grouting holes as an example, the first grouting hole in this layer has a position number of 1, the second grouting hole has a position number of 2, and so on. Assuming there are 11 grouting holes in this layer, the grouting holes located at positions 1, 3, 5, 7, 9, and 11 are the first odd-numbered holes 6; the grouting holes located at positions 2, 4, 6, 8, and 10 are the first even-numbered holes 7.

[0069] In this embodiment, it is also ensured that the first grouting holes corresponding to the upper and lower layers are of the same type. This allows the grout to form a continuous diffusion path in the vertical direction, resulting in more significant support and reinforcement performance. It should be noted that, generally, since the arrangement of the first odd-numbered holes 6 is closer to the core area or critical stress area of ​​the grouting outline 3, grouting the core area first can form mechanical support earlier. Therefore, the first odd-numbered holes 6 are grouted first, followed by the first even-numbered holes 7.

[0070] S300. When grouting the first grouting hole, firstly, all the first sequence odd-numbered holes 6 are grouted in stages. At this time, the first sequence even-numbered holes 7 and the first drainage hole 4 can drain the cross-sectional water outflow into the corresponding dewatering well 11. Then, the first sequence even-numbered holes 7 are grouted in stages. At this time, the first drainage hole 4 can drain the cross-sectional water outflow into the corresponding dewatering well 11.

[0071] In this embodiment, to improve grouting efficiency and quality, and to prevent grout from overflowing from adjacent holes and affecting water sealing, grouting is carried out in an odd-even sequence. The selected grout is a two-component grout of ordinary silicate cement and water glass with a PO 42.5 or higher, which has a strong water-sealing effect. During the process, the first odd-numbered holes 6 are grouted first, while the first even-numbered holes 7 and drainage holes can still drain water. When grouting the first odd-numbered holes 6, the grout spreads to the surrounding area. The ungrouted first even-numbered holes 7 can simultaneously share the drainage function with the first drainage hole 4, preventing the grout from being diluted by groundwater. Then, the first even-numbered holes 7 are grouted. At this point, only the first drainage hole 4 drains water, and the grout in the first odd-numbered holes 6 has initially solidified, forming a certain support. When the first even-numbered holes 7 are grouted, the gaps between the odd-numbered holes can be filled, making the grout distribution more uniform throughout the grouting area and avoiding reinforcement blind spots. This design ensures that the formation remains under low water pressure during grouting, improving the grout consolidation effect.

[0072] Specifically, see Figure 2 and Figure 6 , Figure 7 Step S300 includes the following steps when grouting the first grouting hole:

[0073] S301. Drive a first steel pipe of a predetermined length into the first grouting hole and the first drainage hole 4.

[0074] The steel perforated pipe serves as a "channel carrier" for grouting and drainage. Its walls have grout / water outlet holes, allowing it to transport grout deep into the formation and guide seepage water to the drainage system. The steel perforated pipe, used in conjunction with the aforementioned multi-functional drilling rig, completes the grouting task for the first grouting hole. In practical applications, a pre-set length of the first steel perforated pipe can be obtained by detachably connecting multiple sections, making it more convenient to pull back the pipe. This pre-set length needs to be set according to project requirements.

[0075] S302. A single grouting is performed on the first steel pipe at the odd-numbered hole 6 in the first sequence. At this time, the steel pipe at the even-numbered hole 7 in the first sequence is connected to the drainage pipe. The grouting length of the single grouting is the construction length of the entire cross section of the transverse channel.

[0076] Specifically, the first odd-numbered hole 6 is the starting hole for full-section grouting. At the start of grouting, grout is injected into the stratum through the first steel perforated pipe that has already been driven in. The coverage length of a single grouting is the construction length of the entire cross section of the transverse passage. The grouting range covers the entire cross section inside the tunnel portal and outside the excavation outline, ensuring comprehensive reinforcement and forming a through-type reinforcement zone to avoid connection gaps in segmented grouting.

[0077] During the grouting process, it is inevitable that the original water in the stratum will be "squeezed out" by the pressure of the grout. At this time, the first drainage hole 4 and the first even-numbered hole 7 located outside the grouting outline 3 can play the role of drainage. The water will be "squeezed" and spread in the soil layer, and finally be discharged at the multiple densely arranged first drainage holes 4 and the first even-numbered hole 7.

[0078] S303. Monitor the grouting pressure, and when the grouting pressure reaches the designed final hole pressure, or when the grouting volume has reached the preset grouting volume, pull back one section of the first steel pipe and continue grouting until the first steel pipe is completely pulled back.

[0079] S304. Disconnect the first steel pipe and the drainage pipe at the first even-numbered hole 7 in the first sequence, and repeat the above steps to grout the first grouting hole of the first even-numbered hole 7 in the first sequence.

[0080] Specifically, during the grouting process, it is also necessary to monitor the grouting pressure and grouting volume to determine whether grouting of the first sequence odd-numbered holes 6 can be stopped. In this embodiment, the judgment condition is the designed final hole pressure, which serves as a "mechanical signal" for determining whether the formation of the first sequence even-numbered holes 7 is filled with grout. For example, if the designed final pressure is set to 2 MPa, when the pressure gauge shows that this value has been reached, it indicates that the fracture in the grouting formation corresponding to the current first steel pipe has been filled with grout, and continued grouting may lead to excessive pressure and cause formation uplift. Alternatively, the judgment condition can also be the grouting volume and the preset grouting volume. In terms of quantity comparison, the preset grouting volume here can be twice the "theoretical filling volume" calculated based on the porosity and cross-channel volume of the current construction stratum. When the actual grouting volume reaches this value, it means that the filling has been completed according to the theoretical value. At this time, regardless of whether the pressure meets the standard, the grouting of the current section must be stopped (to avoid grout waste or excessive compression of the stratum). In the actual construction process, because the stratum structure is inherently complex, when any construction judgment condition is met, the first steel pipe can be pulled back one section to continue grouting until all the first steel pipes are pulled back, forming a staged grouting effect.

[0081] After drilling is completed, the first steel pipe of a preset length can be inserted into the deepest part of the stratum in the first grouting hole for grouting. After the grouting reaches the standard, one section is pulled back (the length of each section pulled back can be the same as the length of the segmented drilling, both not exceeding 1.5m). At this time, the grout begins to concentrate and fill the stratum to a depth of 10-1.5=8.5 meters. After reaching the standard again, the second section is pulled back to fill the stratum to a depth of 8.5-1.5=7 meters, and so on, until all sections are pulled back, achieving full-length grouting coverage from the "deepest end" to the "hole opening". In this way, this method can effectively avoid the problem of grout concentration caused by grouting the first steel pipe at once. At the same time, by pulling back one section of steel pipe, each section of steel pipe can be targeted to fill the stratum at the corresponding depth, ensuring uniform grouting throughout the entire cross-sectional length of the transverse channel.

[0082] After completing the graded grouting of each of the first-order odd-numbered holes 6, the next step is to grout the first-order even-numbered holes 7. The specific method and principle are the same as the grouting process of the first-order odd-numbered holes 6. This can be carried out after disconnecting the connection between the first steel flower pipe and the drainage pipe at the first-order even-numbered holes 7. Finally, the operation of grouting all the first grouting holes within the grouting range is completed, thus completing the full-section deep hole grouting of the transverse channel.

[0083] See Figure 8 S400, the raw water collected in the dewatering well 11 is pumped into the recharge well 10, and the raw water is recharged into the soil at the construction site by the recharge well 10.

[0084] To prevent groundwater loss during station construction from causing pore pressure reduction, soil compression, and potential ground subsidence (which could affect surrounding buildings and pipelines), this application uses a first drainage hole 4 connected to a dewatering well 11 to collect water discharged during grouting. The collected water in the dewatering well 11 is then pumped back into the soil surrounding the construction area via a pump and a recharge well 10. This maintains stable groundwater levels, balances pore water pressure, reduces ground deformation caused by groundwater loss, and protects the surrounding environment. Furthermore, in this embodiment, to increase the coverage area of ​​drainage and recharge, improve drainage efficiency, and enhance recharge control precision, multiple recharge wells 10 and dewatering wells 11 are preferably arranged according to engineering requirements. For example, see [link to relevant documentation]. Figure 8 As shown, the recharge wells 10 include multiple recharge wells evenly distributed along the outer side of the foundation pit: a first recharge well 101, a second recharge well 102, a third recharge well 103, a fourth recharge well 104, a fifth recharge well 105, a sixth recharge well 106, a seventh recharge well 107, an eighth recharge well 108, a ninth recharge well 109, a tenth recharge well 1010, an eleventh recharge well 1011, a twelfth recharge well 1012, a thirteenth recharge well 1013, a fourteenth recharge well 1014, a fifteenth recharge well 1015, a sixteenth recharge well 1016, and a seventeenth recharge well 1017. Recharge well 1017; In addition, dewatering well 11 includes a first dewatering well 111, a second dewatering well 112, a third dewatering well 113, a fourth dewatering well 114, a fifth dewatering well 115, a sixth dewatering well 116, a seventh dewatering well 117, an eighth dewatering well 118, a ninth dewatering well 119, and a tenth dewatering well 1110, which are evenly distributed inside the foundation pit; It should be noted that the specific location and number of recharge well 10 and dewatering well 11 are not limited in this embodiment of the application, and can be adapted to the actual construction needs.

[0085] See Figure 3 and Figure 6 , Figure 7 The method further includes: after verifying that the grouting result of the first grouting hole is qualified, proceeding with the construction of the horizontal channel large pipe shed 1. The construction of the horizontal channel large pipe shed 1 specifically includes:

[0086] S500. According to the preset specifications of the horizontal passage large pipe shed 1, the perforated pipes and solid pipes are arranged at intervals to construct the horizontal passage large pipe shed 1. Among them, the perforated pipes are used for grouting, and the solid pipes are used for backfilling with cement grout. The perforated pipes are set at the center line of the horizontal passage large pipe shed 1.

[0087] In the above process, the grouting of the first grouting hole has made the stratum around the transverse passage more compact. After the grouting structure is qualified (for example, the stratum strength and water-stopping effect meet the standards), it can be ensured that the stratum will not collapse or water surge due to disturbance during the subsequent construction of the large pipe shed. Here, the transverse passage large pipe shed 1 is a kind of "advanced support structure", which is equivalent to driving a row of steel pipes into the periphery of the subsequent transverse passage excavation range to form excavation protection. It can not only further reinforce the stratum, but also directly resist the soil pressure during excavation, thus ensuring the safety of excavation.

[0088] Specifically, in this embodiment, the steel pipes selected are perforated pipes and solid pipes. The perforated pipes have dense grout outlets on their walls for injecting grout into the surrounding strata, which can further fill the gaps between the pipe roof and the strata, enhancing the bonding force between the strata and the pipe roof. The solid pipes have no grout outlets on their walls, and the internal injection of cement grout makes the steel pipes themselves stronger, significantly increasing their rigidity and facilitating their structural support function. In order to ensure that the construction of the transverse passage large pipe roof 1 takes into account both filling gaps and providing structural support, the perforated pipes and solid pipes are arranged alternately during construction: ensuring the reinforcement effect while making the overall stress on the pipe roof more uniform.

[0089] It should be noted that the purpose of installing perforated pipes at the centerline of the transverse tunnel pipe shed 1 is because the centerline of the transverse tunnel is the area where the stress is most concentrated during excavation (the top soil pressure and the squeezing pressure on both sides are superimposed here). Using perforated pipes at the centerline allows for targeted grouting into the core area, strengthening the strata near the centerline and preventing the pipe shed centerline from deforming due to excessive stress.

[0090] S600. When grouting into the perforated pipe, open the vent valve at the orifice of the perforated pipe and stop grouting when grout is detected flowing out of the vent valve.

[0091] In actual construction operations, when grouting the perforated pipe, the grout can be a two-component grout of ordinary silicate cement and water glass with a strong water-stopping effect of not less than PO 42.5. At the same time, it is necessary to ensure that the grouting is full and to avoid the influence of air on the reinforcement effect. Therefore, in this embodiment, an exhaust pipe is installed in the upper part of the perforated pipe or at the pipe opening, and an exhaust valve is installed on the exhaust pipe. The exhaust valve is kept open during grouting, and the grouting is stopped when the grout is detected flowing out of the exhaust valve. This phenomenon indicates that the air has been completely expelled. Stopping the grouting at this time can ensure that the stratum around the perforated pipe is evenly filled with grout and will not cause grout waste or stratum uplift due to excessive grouting.

[0092] S700. When backfilling with cement grout into the solid pipe, if leakage of grout is detected on the outer valve of the horizontal channel large pipe shed 1, close the outer valve and continue to inject cement grout until the cement grout injection pressure is greater than the preset pressure value and is maintained for a preset time period, or when grout appears on the wall of the horizontal channel large pipe shed 1 and the amount of cement grout injected is greater than the preset injection value, stop injecting cement grout.

[0093] In actual construction, the completed pipe roof steel pipes are required to have 6-point joints and valves installed on the inside and outside according to the design. Therefore, the monitoring of the solid pipe can be carried out by monitoring the valves on the outside of the horizontal channel pipe roof 1. After the solid pipe is filled, the grout will leak out from the gap between the steel pipe and the external structure, which is called "grout leakage from the outside valve". At this time, it can be indicated that the solid pipe is basically filled. At this time, closing the outside valve can prevent the grout from continuing to leak out and instead use high pressure to compact the grout inside the pipe.

[0094] The two conditions for stopping cement grouting here are still constrained by pressure and grouting volume. For example, when the cement grouting pressure reaches the standard and the pressure is maintained for the preset time period (e.g., 2-3 minutes), it indicates that the cement grout has been fully compacted in the pipe, and the combined rigidity of the solid pipe and cement grout after solidification meets the standard. In addition, when grout appears on the outer wall of the horizontal channel pipe shed 1 and the grouting volume reaches the standard (the cement grouting volume is greater than the preset grouting value, which can be 80% of the theoretical grouting value, without special limitation), it also indicates that the pipe is full of cement grout. Stopping at this time can avoid over-grouting and structural deformation. The specific preset pressure value, preset time period, and preset grouting value are set by technicians according to the actual project, and no special limitation is made here.

[0095] It should be noted that, since the steel pipes in the pipe shed are designed to conform to the specifications of the pipe shed, the grouting operation must be carried out in accordance with the rule of "from bottom to top, from both sides to the middle, and from thin to thick grout directly at the pipe shed opening".

[0096] The method also includes: after the construction of the transverse tunnel pipe shed 1 is completed, the transverse tunnel is excavated based on the support of the transverse tunnel pipe shed 1, and after the excavation of the transverse tunnel is completed, the longitudinal guide tunnel is constructed.

[0097] Specifically, see Figure 4 and Figure 9 The excavation of the transverse passage includes the following steps:

[0098] S800, construct the initial support 12 for the cross passage excavation. The initial support 12 is equipped with an arch top and sides according to construction requirements, and the arch top and sides of the initial support 12 are equipped with compensation grouting pipes 13.

[0099] After the transverse passage is excavated, the exposed surrounding rock will lose its original balance and is prone to collapse or deformation due to excessive pressure. Therefore, it is necessary to construct initial support 12 during the excavation of the transverse passage. The arch top and edges of the initial support 12 work together to increase the support for the surrounding rock. The arch top and edges of the initial support 12 can be found in [reference needed]. Figure 8 The structure shown has an arched top for the initial support 12, which is the arch top, and the two sides of the arch top are the two sides.

[0100] In actual construction operations, due to reasons such as the excavation surface not being perfectly flat, the presence of air bubbles in the shotcrete, and the possibility of slight settlement in the surrounding rock due to stress release, gaps inevitably appear between the initial support 12 and the external soil layer. If these gaps are not addressed, they will lead to uneven stress on the support structure. Therefore, in this embodiment, in order to block water and strengthen the structure, backfill grouting should be carried out in a timely manner behind the initial support (the principle of backfill grouting behind the initial support 12 is to ensure close contact between the initial support 12 and the soil layer). Therefore, radial compensation grouting pipes 13 are provided at the top and sides of the arch of the initial support 12 to fill the gaps between the initial support 12 and the external soil layer. It should be noted that the compensation grouting pipes 13 can be pre-embedded at the top and sides of the arch, with one end leading to the gap between the support and the soil layer and the other end remaining inside the support for easy grouting operations. At the same time, the backfill grouting should be selected based on the size of the gaps behind the initial support 12 (or the stratum) or the water test results, using either cement grout or cement mortar. No special limitations are imposed here.

[0101] It should be explained that the cross passage in this embodiment of the application adopts the step method for cross-sectional excavation. Before excavation, full-section grouting and the construction of large pipe sheds have been completed. Before excavation, advance small pipes are constructed for advance support. Then, the upper step of the upper guide tunnel of the cross passage is excavated using the step method. After excavation, the initial support 12 and anchor pipes are promptly installed. Then, the lower step of the upper guide tunnel is excavated. Similarly, the transverse diaphragm and anchor pipes are promptly installed and quickly closed into a ring. After that, the upper step of the lower guide tunnel is excavated. Note that the lower guide tunnel must maintain a distance of more than 10 meters from the closed upper guide tunnel. Finally, the lower step of the lower guide tunnel is excavated. After excavation, it is promptly closed into a ring.

[0102] S900 When the initial support 12 reaches the first preset height, or when the distance from the tunnel face at the top of the arch reaches the first preset height, the initial support 12 and the external soil layer are backfilled and grouted through the compensation grouting pipe 13.

[0103] In the actual backfilling and grouting process, there are two judgment conditions: the initial support 12 reaching the first preset height is used as a marker. For example, when the initial support 12 has been constructed to the first preset height (e.g., 3 meters) along the longitudinal direction of the transverse passage from the excavation starting point, the initial support 12 has formed a "closed section" of a certain length, and the void distribution is relatively stable. It is suitable to fill the void area within this range by grouting to avoid the void expansion caused by subsequent excavation; or, when the excavation reaches the first preset height (e.g., 3 meters) from the tunnel face at the top of the arch, the tunnel face is the forefront of the excavation. When the tunnel face advances to the first preset height from the top of the arch, it is necessary to grout and fill the voids between the support and the soil layer near the top of the arch in advance. This is because the top of the arch is the area with the most concentrated stress. If there are voids, the top of the arch may settle and crack due to the loss of soil support during subsequent excavation. Grouting in advance can reinforce the weak area.

[0104] See below Figure 5 as well as Figures 10-13 After the transverse tunnel excavation is completed, the longitudinal pilot tunnel can be constructed. At this time, the same procedure is required: full-section grouting of the pilot tunnel excavation face. The principle is basically the same as that of full-section deep hole grouting of the transverse tunnel, including the following steps:

[0105] S110. Define the full-section deep hole grouting range of the longitudinal guide tunnel and confirm the grouting outline of the longitudinal guide tunnel section based on the grouting range of the longitudinal guide tunnel; the longitudinal guide tunnel section grouting outline is provided with second grouting holes and second drainage holes 5 inside and outside respectively; wherein, the second grouting holes are divided into second-order odd holes 8 and second-order even holes 9 according to the division method of first-order odd holes 6 and first-order even holes 7;

[0106] When performing full-section grouting of the longitudinal guide tunnel, it is also necessary to clearly define the grouting outline of the longitudinal guide tunnel section and locate the second grouting hole (further divided into second odd-numbered hole 8 and second even-numbered hole 9 according to the parity of their sequential digits) and the second drainage hole 5 based on this grouting outline. Specific parameters can be used for details. Figure 9 The diagram shows the structure. In the actual construction process, the second grouting hole is drilled using a multi-functional drilling rig with a hollow drill rod. The drilling rig is positioned according to the designated location, and under the guidance of technicians, the angle of the drill rod is adjusted. After aligning with the hole position, the drilling rig must not move to ensure that the center-to-center distance between each second grouting hole is less than the preset distance (e.g., 1000mm). It is also necessary to ensure that the spray radius of the grouting pipe is not less than 650mm, so that the adjacent second grouting holes interlock within a certain range, so that the grout can spread evenly in the soil layer based on the spray radius of the grouting pipe during injection.

[0107] S210. Drive a second steel pipe into the second drainage hole 5. The second steel pipe connected to the second drainage hole 5 on both sides of the longitudinal guide tunnel is connected to the dewatering well 11 and the junction of the underground section and the open-cut section of the station, respectively. The second steel pipe connected to the junction can discharge the water from the cross section of the longitudinal guide tunnel into the dewatering well 11 of the open-cut foundation pit.

[0108] During the grouting process, it is also necessary to insert corresponding second steel pipes into the second grouting hole and the second drainage hole 5. The second steel pipe at the second drainage hole 5 has a different design with different connection positions on both sides. One side is connected to the dewatering well 11, which can directly discharge the seepage water from the excavation face of the pilot tunnel to a special dewatering well (temporary collection well) to quickly reduce the water pressure inside the pilot tunnel. The other side is connected to the junction of the underground section and the open-cut section of the station. The existing dewatering system of the open-cut section (such as the dewatering well of the open-cut foundation pit) can be used to discharge the seepage water from the pilot tunnel to the collection well of the open-cut foundation pit. In this way, through the coordination of the drainage system, it is possible to avoid adding too many dewatering facilities to the pilot tunnel, thereby saving certain costs.

[0109] It should be noted that the terms "second steel pipe" and "first steel pipe" are used for ease of explanation and are essentially the same, referring to steel pipe structures without any distinction between "second" and "first". During station construction, the cut-and-cover section is the underground concealed construction portion, while the open-cut section is the surface excavation portion. At the junction of the open-cut section and the PBA cut-and-cover section, the clearance of the open-cut section should be consistent with the structural clearance of the cut-and-cover section. The frame beam of the open-cut section should be joined to the ring frame reinforcement beam of the cut-and-cover section, the frame beam of the open-cut section should be joined to the steel pipe pile 14 of the cut-and-cover section, and the side wall of the open-cut section should be joined to the side wall of the cut-and-cover section. During construction, the construction sequence should be appropriately arranged to smoothly transition between the open-cut and cut-and-cover junctions.

[0110] S310. Drive the second steel pipe into the second grouting hole, and grout the odd-numbered hole 8 first and then the even-numbered hole 9 in the second sequence to complete the full-section grouting of the longitudinal guide tunnel.

[0111] The grouting method and grouting judgment methods for the second grouting hole can be the same as those for the first grouting hole. Grouting is completed when all the second grouting holes meet the grouting completion criteria, thus completing the full-section grouting operation of the longitudinal guide tunnel. Subsequently, the construction of the longitudinal guide tunnel large pipe roof 2 and the excavation of the longitudinal guide tunnel are carried out in sequence. The construction of the longitudinal guide tunnel large pipe roof and the excavation of the longitudinal guide tunnel follow the same principle as the construction of the transverse tunnel pipe roof and the excavation of the transverse tunnel. That is, it is also necessary to carry out the operation of staggered arrangement of perforated pipes and solid pipes and the construction of initial support 12, etc., which will not be elaborated in detail here.

[0112] In a preferred embodiment, after the longitudinal guide tunnel is excavated, in order to enhance the water-stopping effect of the longitudinal guide tunnel, the following steps are further included:

[0113] Step 1: According to the station construction requirements, the distribution of each side pile in the longitudinal guide tunnel is obtained by surveying and setting out, and steel pipe piles 14 are driven based on the obtained side pile positions.

[0114] Step 2: Install at least one side pile grouting pipe 15 between every two adjacent steel pipe piles 14; the grouting pipe is filled with grout, and all the side pile grouting pipes 15 and steel pipe piles 14 are used together to form a water-stop curtain inside the tunnel.

[0115] In actual construction operations, surveying and setting out is the process of converting the "theoretical position" on the design drawings into the "actual position" on the construction site. In the longitudinal pilot tunnel, it is necessary to accurately determine the position of each side pile using surveying instruments (such as total station, GPS) according to the station construction requirements (such as the axis position, width, and burial depth of the pilot tunnel). After obtaining the position of each side pile, steel pipe piles 14 can be driven into each position to effectively prevent the collapse of both sides of the pilot tunnel.

[0116] In addition, step two also explains that after the steel pipe piles 14 are driven in, side pile grouting pipes 15 need to be driven between the two steel pipe piles 14. The core function of the side pile grouting pipes 15 is to inject grout into the stratum (the grout can be ordinary silicate cement + water glass double liquid grout as the grout for grouting) to fill the soil pores. The grout injected by the side pile grouting pipes 15 is usually cement grout or cement-water glass double liquid grout. The grout will diffuse around under pressure and form a continuous and closed water-stop curtain with the steel pipe piles 14 around the guide tunnel, isolating the guide tunnel from the external groundwater.

[0117] Based on the above, the present invention provides a method for non-dewatering construction of underground subway stations near Quanhu Station. This method employs full-section grouting for water interception, pipe roof grouting, and backfill grouting of the initial support 12 for comprehensive waterproofing. Simultaneously, during the longitudinal guide tunnel construction, grouting pipes are installed between the side piles for water stoppage, integrating water stoppage, water interception, and waterproofing. Finally, the water discharged from the grouting is drained through the dewatering well 11 and then reinjected into the ground through the reinjection well 10, achieving non-dewatering construction. This solves the problem of non-dewatering construction in underground subway station projects, ensuring the safety and reliability of the underground subway station construction process and guaranteeing construction efficiency. It has high promotional value in the field of subway station construction.

[0118] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for non-dewatering construction of tunnel near Quanhu Metro Station, characterized in that, include: According to the station construction requirements, the full-section deep hole grouting range of the cross passage was marked, and the full-section grouting outline was confirmed based on the grouting range; several first grouting holes and first drainage holes were arranged sequentially inside and outside the grouting outline. The first drainage hole is connected to the dewatering well through a drainage pipe, and all the first grouting holes are divided into first-order odd-numbered holes and first-order even-numbered holes according to their distribution positions; the first-order odd-numbered holes and the first-order even-numbered holes are arranged at intervals in the first direction; When grouting the first grouting hole, firstly, all the first sequential odd-numbered holes are grouted in stages. At this time, both the first sequential even-numbered holes and the first drainage hole can discharge the cross-sectional water outflow into the corresponding dewatering well. Then, the first sequential even-numbered holes are grouted in stages. At this time, the first drainage hole can discharge the cross-sectional water outflow into the corresponding dewatering well. The raw water collected in the dewatering well is pumped into the recharge well, and the raw water is then recharged into the soil at the construction site through the recharge well. Several first grouting holes are arranged in layers from top to bottom within the grouting outline, following its trend. All first grouting holes are divided into first-order odd-numbered holes and first-order even-numbered holes according to their distribution positions. Each first grouting hole is divided into first-order odd-numbered holes and first-order even-numbered holes according to the parity of its position number in that layer. Moreover, each first grouting hole in each layer has the same type as the first grouting holes above and below it after division. When grouting the first grouting hole, all the first sequential odd-numbered holes are first grouted in stages. At this time, the first sequential even-numbered holes and the first drainage hole can discharge the cross-sectional water into the corresponding dewatering well. Then, staged grouting is performed on the first even-numbered holes. At this time, the first drainage hole can discharge the water from the cross-section into the corresponding dewatering well, including: A first steel pipe of a predetermined length is driven into the first grouting hole and the first drainage hole; A single grouting is performed on the first steel pipe at the odd-numbered holes in the first sequence, at which time the first steel pipe at the even-numbered holes in the first sequence is connected to the drainage pipe; the grouting length of the single grouting is the construction length of the entire cross section of the transverse channel; Monitor the grouting pressure, and when the grouting pressure reaches the designed final hole pressure, or when the grouting volume has reached the preset grouting volume, pull back one section of the first steel pipe and continue grouting until the first steel pipe is completely pulled back. Disconnect the first steel pipe at the first even-numbered hole in the first sequence from the drainage pipe, and repeat the above steps to grout the first grouting hole at the first even-numbered hole in the first sequence.

2. The method for non-dewatering construction of the tunnel near Quanhu Metro Station according to claim 1, characterized in that, The method also includes: After the grouting result of the first grouting hole is found to be qualified, the construction of the horizontal channel pipe shed will proceed. The construction of the transverse passage pipe shed includes: According to the preset specifications for the transverse passage pipe shed, perforated pipes and solid pipes are arranged at intervals to construct the transverse passage pipe shed; wherein, the perforated pipes are used for grouting, and the solid pipes are used for internal cement grout backfilling, and perforated pipes are set at the centerline of the transverse passage pipe shed. When grouting into the perforated pipe, open the vent valve at the orifice of the perforated pipe, and stop grouting when grout is detected flowing out of the vent valve; When backfilling with cement grout into the solid pipe, if leakage of grout is detected at the valve on the outside of the transverse channel pipe shed, the valve is closed and cement grout injection continues until the cement grout injection pressure is greater than the preset pressure value and remains at the preset time period, or when grout appears on the wall of the transverse channel pipe shed and the amount of cement grout injected is greater than the preset injection value, then cement grout injection is stopped.

3. The method for non-dewatering construction of the tunnel near Quanhu Metro Station according to claim 2, characterized in that, The method also includes: After the construction of the transverse tunnel pipe shed is completed, the transverse tunnel is excavated based on the support of the transverse tunnel pipe shed, and after the excavation of the transverse tunnel is completed, the longitudinal guide tunnel is constructed. The excavated transverse passage includes: The initial support for the cross passage excavation is constructed. The initial support is equipped with an arch top and sides according to construction requirements, and the arch top and sides of the initial support are equipped with compensating grouting pipes. When the initial support reaches the first preset height, or when the cross passage is excavated to the distance from the working face at the top of the arch to the first preset height, the initial support and the external soil layer are backfilled and grouted through the compensation grouting pipe.

4. The method for non-dewatering construction of the tunnel near Quanhu Metro Station according to claim 3, characterized in that, Construction of the longitudinal pilot tunnel includes: The full-section deep hole grouting range of the longitudinal guide tunnel is calibrated, and the grouting outline of the longitudinal guide tunnel section is confirmed based on the grouting range of the longitudinal guide tunnel. Second grouting holes and second drainage holes are respectively opened inside and outside the grouting outline of the longitudinal guide tunnel section. The second grouting holes are divided into second-order odd holes and second-order even holes according to the first-order odd hole and the first-order even hole division method. A second steel pipe is driven into the second drainage hole. The second steel pipes connected to the second drainage holes on both sides of the longitudinal guide tunnel are respectively connected to the dewatering well and the junction of the underground section and the open-cut section of the station. The second steel pipe connected to the junction can discharge the water from the cross section of the longitudinal guide tunnel into the dewatering well of the open-cut foundation pit. A second steel pipe is driven into the second grouting hole, and the longitudinal guide tunnel is grouted in the order of first grouting the odd-numbered holes and then grouting the even-numbered holes.

5. The method for non-dewatering construction of underground tunnel near Quanhu Metro Station according to claim 4, characterized in that, After completing the full-section grouting of the longitudinal guide tunnel, the method further includes: After the grouting of the entire longitudinal guide tunnel is qualified, the construction of the longitudinal guide tunnel pipe shed and the excavation of the longitudinal guide tunnel are carried out in sequence.

6. The method for non-dewatering construction of underground tunnel near Quanhu Metro Station according to claim 5, characterized in that, After the longitudinal pilot tunnel is excavated, the method also includes: According to the station construction requirements, the distribution of each side pile in the longitudinal guide tunnel was obtained by surveying and setting out, and steel pipe piles were driven based on the obtained side pile positions. At least one side pile grouting pipe is installed between every two adjacent steel pipe piles; the side pile grouting pipe is filled with grout, and all the side pile grouting pipes and the steel pipe piles are used together to form a water-stop curtain inside the tunnel.

7. The method for non-dewatering construction of underground tunnel near Quanhu Metro Station according to claim 4, characterized in that, The center-to-center distance between each of the first grouting holes and between each of the second grouting holes is less than a preset distance; and there is mutual interlocking between two adjacent first grouting holes and two adjacent second grouting holes based on the set grouting pipe injection radius.

Images