Tunnel adit gushing water treatment method

Abstract

The invention discloses a water gushing treatment method for a tunnel adit, and aims to solve the technical problems that drainage of the tunnel adit is difficult and potential safety hazards exist in a complex strong water gushing environment. Advanced geological forecast is carried out on the tunnel face of the adit by adopting a geophysical prospecting method in combination with a horizontal advanced hole exploration mode, and the geological forecast precision of the unexcavated water-rich section of the adit is improved; through the graded relay drainage system, the technical problem that water burst in the adit moves along with the tunnel face of the adit and is not pumped and drained in time is solved; through the cooperative water blocking structure of advanced fixed-point grouting, system grouting and chemical grouting and in cooperation with a drainage system, groundwater exposure of the water-rich section of the adit is restrained, the current situation that a water curtain hole of the water-rich section of the adit is excavated is effectively improved, and the construction safety coefficient is greatly increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel construction, in particular to a tunnel branch hole water gushing treatment method. BACKGROUND

[0002] In tunnel engineering construction, especially in deep and long tunnel construction, the branch hole as a transportation channel and a ventilation and drainage channel often passes through water-rich rock layers and encounters water gushing problems. The traditional branch hole water gushing treatment method mainly relies on the way of strengthening the number and scale of drainage equipment to pump the gushing water outside the hole. Some projects will combine local grouting water plugging measures. This kind of method can play a certain role under the condition of small water gushing amount and limited supply source, but it is often difficult to achieve ideal results when facing the water gushing characteristics of "many points, wide surface, slow attenuation, and following the tunnel face" in the geological conditions of developed bedrock fissure water, abundant rainfall recharge, and dense distribution of gushing points. On the one hand, the capacity of the drainage system always lags behind the dynamic growth of the water gushing amount, resulting in frequent flooding of the tunnel face, causing frequent interruption of construction, and occupying a large amount of process time in the foundation drainage link, which seriously restricts the excavation and support progress. On the other hand, under the uncontrolled strong drainage mode, the daily drainage amount can reach several thousand cubic meters, and the continuous pumping causes the regional groundwater level to continue to decline, which not only threatens the stability of the rock mass around the chamber, but also may cause ecological environment problems and social contradictions such as the withering of surface vegetation and the drying up of residents' wells. More importantly, the water gushing of the tunnel face will continuously appear new water outflow points, and linear flow and stock water are distributed on the wall in the excavated section, which not only increases the rebound amount of shotcrete and the risk of support leakage, but also exists safety hazards such as electrical leakage of mechanical and electrical equipment and slippery transportation.

[0003] The information disclosed in this BACKGROUND section is only for the purpose of enhancing the understanding of the background of the present disclosure and should not be taken as admitting that the information forms prior art that is known to those skilled in the art. SUMMARY

[0004] In view of at least one of the above technical problems, the present disclosure provides a tunnel branch hole water gushing treatment method, aiming to solve the technical problems of difficult drainage and safety hazards of tunnel branch holes in complex strong water gushing environment.

[0005] According to one aspect of the present disclosure, a tunnel branch hole water gushing treatment method is provided, comprising the following steps: (1) determining the position and range of the water-rich section of the unexcavated section of the branch hole by geophysical prospecting method, and then excavating the branch hole; (2) With the tunneling of the branch hole, a drainage system is arranged in the branch hole; the drainage system comprises a temporary water collecting pit arranged behind the branch hole face, a plurality of water tanks arranged along the tunneling direction of the branch hole, and water collecting pits arranged on both sides of each water tank; a drainage pump group for pumping water out of the branch hole is arranged in the temporary water collecting pit and in each water tank; and a water pumping pump group for pumping water in the water collecting pit into the corresponding water tank is arranged in the water collecting pit; (3) When the branch hole face is 4-6 m away from the water-rich section, a horizontal advanced probe hole is arranged at the branch hole face to obtain the geological information of the water-rich section; (4) The advanced point grouting is performed at the water outlet position of the horizontal advanced probe hole, and then the branch hole is excavated in the water-rich section; (5) After the branch hole is excavated for a certain distance, the uncovered re-grouting is performed on the excavated section of the branch hole, and the water yield of the branch hole face is determined; when the water yield has not decreased, step (4) is repeated until the excavation of the branch hole is completed.

[0006] In some embodiments of the present disclosure, in step (3), the horizontal advanced probe hole comprises a plurality of horizontal probe holes distributed at intervals along the inside of the branch hole excavation contour line.

[0007] In some embodiments of the present disclosure, in steps (4) and (5), the advanced point grouting comprises the following sub-steps: (41) A hole mouth pipe and a water stop valve are installed at the water outlet position of each horizontal probe hole; (42) C30 sprayed concrete is used to close the water outlet fissure on the branch hole face, and the thickness of the closure is at least 20 cm; (43) Sectional forward grouting is used to fill cement slurry into each hole mouth pipe.

[0008] In some embodiments of the present disclosure, in step (5), the uncovered re-grouting comprises arranging a plurality of system grouting holes at intervals along the tunneling direction of the excavated section of the branch hole and grouting, and arranging chemical grouting holes at the water outlet points and the fissure cavity positions of the excavated section of the branch hole and grouting.

[0009] In some embodiments of the present disclosure, the system grouting holes comprise a plurality of grouting holes one arranged in the range of the top arch of the excavated section of the branch hole in a plum blossom pattern, and each grouting hole one is grouted with cement and water glass double slurry.

[0010] In some embodiments of the present disclosure, the chemical grouting holes comprise a plurality of grouting holes two drilled around the water outlet points and the fissure cavity positions of the excavated section of the branch hole, and each grouting hole two is grouted with HCH-III type double liquid reinforcing material and HCH-I type organic polymer grouting material.

[0011] The one or more technical solutions provided in the embodiments of the present application have at least any of the following technical effects or advantages: (1) By using the method of geophysical prospecting combined with horizontal advanced exploration hole to make advanced geological prediction on the tunneling face of the branch hole, the geological prediction accuracy of the water-rich section of the unexcavated section of the branch hole is improved, the precise positioning of the water gushing source and the water gushing early warning are realized; in addition, through the hierarchical relay drainage system, the technical problem of not timely pumping and draining caused by the movement of the branch hole tunneling face is solved without affecting the normal tunneling construction of the branch hole, and the pumping efficiency of the water gushing in the branch hole is improved.

[0012] (2) By using the collaborative water blocking structure of advanced fixed-point grouting, systematic grouting and chemical grouting, and the layout of the drainage system, the "blocking and draining combination, water blocking and limiting draining" mode is adopted to greatly reduce the pumping pressure of the water gushing in the branch hole, reduce the influence of groundwater on the excavation and support of the branch hole and the quality of the secondary lining concrete in the later period, improve the construction efficiency of the branch hole and speed up the construction progress; at the same time, it also avoids the decline of the groundwater level in the excavation area of the branch hole caused by the unlimited pumping of the drainage system, thereby affecting the vegetation ecological environment and the villagers' domestic water. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a drainage system layout diagram of the tunnel branch hole water gushing treatment method in an embodiment of the present application.

[0014] Figure 2 It is an advanced horizontal exploration hole layout diagram of the tunnel branch hole water gushing treatment method in an embodiment of the present application.

[0015] Figure 3 It is an advanced fixed-point grouting flowchart of the tunnel branch hole water gushing treatment method in an embodiment of the present application.

[0016] Figure 4 It is a systematic grouting layout diagram of the tunnel branch hole water gushing treatment method in an embodiment of the present application.

[0017] Figure 5 It is a systematic grouting section view of the tunnel branch hole water gushing treatment method in an embodiment of the present application.

[0018] Figure 6 It is a systematic grouting flowchart of the tunnel branch hole water gushing treatment method in an embodiment of the present application.

[0019] Figure 7 It is a chemical grouting layout diagram of the tunnel branch hole water gushing treatment method in an embodiment of the present application.

[0020] In the above figures, 1 is a branch hole, 2 is a branch hole face, 3 is a temporary sump, 4 is a water tank, 5 is a sump, 6 is a pump station, 7 is a drainage pump group 1, 8 is a drainage pump group, 9 is a drainage pump group 2, 10 is a horizontal probe hole, 11 is a grouting hole 1, 12 is a grouting hole 2, 13 is a water outlet, and 14 is a fissure cavity. DETAILED DESCRIPTION

[0021] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer", "vertical", "horizontal", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. The present application involves "connection" and "coupling", unless otherwise specified, which includes direct and indirect connection (coupling).

[0022] In the following examples, the unit modules, parts, structures, mechanisms or sensors and the like, unless otherwise specified, are all conventional commercially available products.

[0023] In order to better understand the technical solutions of the present application, the above technical solutions will be described in detail below in conjunction with the drawings and specific embodiments of the specification.

[0024] As shown in Figure 1 , 2 In this embodiment, the tunnel branch hole 1 is a permanent maintenance branch hole, with a total length of 892.68m and a comprehensive slope of 8.98%. The surrounding rock is mainly composed of tuff (class IV-V). The open-cut section is 45.9m long with a slope of 13.48%, and the tunnel excavation section is 846.78m long with a slope of 9.35%. A 20m long flat section is provided every 150m, and a circular arch straight wall type cross section is adopted. According to the analysis of the site construction, the groundwater type of the branch hole 1 in this embodiment is bedrock fissure water, which is replenished by surface rainfall and stored through bedrock fissures and structures. It is easy to emerge after the excavation of the branch hole 1, and has the characteristics of "many points, wide surface, slow decay, and following the face".

[0025] In order to solve the technical problems of difficult drainage of the tunnel branch hole 1 in a complex strong gushing water environment and safety hazards, the present example discloses a tunnel branch hole 1 gushing water treatment method, which mainly adopts the method of "combination of plugging and drainage, water plugging and limited drainage", realizes the control of gushing water in the tunnel branch hole 1, does not affect the normal tunneling, guarantees the construction safety, and protects the groundwater environment of the excavation area; the specific scheme is as follows: (1) In order to ensure that the risk of water inrush is controlled in advance before the excavation of the branch tunnel 1, the location and range of the water-rich section of the unexcavated section of the branch tunnel 1 are determined by geophysical exploration, and then the branch tunnel 1 is excavated. Preferably, the surface transient electromagnetic exploration technology is used to lock the approximate range and burial depth of the water-rich section, which avoids work stoppage or safety accidents caused by sudden water inrush, and provides a target direction for subsequent horizontal advance borehole construction.

[0026] (2) To enhance the drainage capacity of the adit 1, a drainage system is installed within the adit 1 as the working face 2 advances, ensuring timely response to potential large-scale water inrushes in the unexcavated section of the adit. In this embodiment, as... Figure 1 As shown, the drainage system includes a temporary sump 3 located 8m behind the tunnel face 2, several water tanks 4 located along the tunnel excavation direction and on the flat slope section inside the tunnel 1, and sump pits 5 located on both sides of each water tank 4 along the tunnel excavation direction. Drainage pump sets for pumping water to the outside of the tunnel 1 are installed in the temporary sump 3 and each water tank 4. Specifically, a pump station 6 is installed in the temporary sump 3 to pump water from the sump to the outside of the tunnel through corresponding pipelines; a drainage pump set 7 is installed in each water tank 4 to pump water from the tank 4 to the outside of the tunnel 1 through corresponding pipelines; and a pump set 8 is installed in each sump pit 5 to pump water from the sump pit 5 to the corresponding water tank 4 through corresponding pipelines.

[0027] Furthermore, the temporary sump 3 is dynamically configured as the tunnel face moves; the pumping station 6 includes two 132kW pumps with a flow rate of 480 m³ / h installed within the sump. 3 The drainage pump unit 7 includes two 45kW multistage centrifugal pumps installed in the water tank, with each pump having a flow rate of 106m³ / h. 3 The pumping unit 8 has a head of 101m and a flow rate of 101m / h. It includes a 15kW sewage pump installed in the sump 5. Preferably, the corresponding pipelines of the pumping station 6, drainage pump group 7, and pumping unit 8 are laid along the right side of the branch tunnel 1, ensuring that the maximum inflow occurring in 24 hours is discharged within 20 hours to avoid energy waste caused by pipeline blockage or excessive flow velocity. The number of pumps in the pumping station, drainage pump group 7, and pumping unit can be increased accordingly based on the inflow situation in the branch tunnel 1. The water tank 4 has a size of 22m. 3 Water from the branch tunnel 1 flows downhill into the water collection pits 5 located on both sides of the water tank 4, and is then pumped into the water tank 4. This facilitates the pumping out of the branch tunnel and improves drainage efficiency.

[0028] Furthermore, after the adit 1 has been excavated to a certain distance, a fixed water reservoir can be installed inside the adit 1 to collect and concentrate the water from the adit face 2 and the water collection pits laid along the excavation direction of the adit 1 into the fixed water reservoir and pump it out of the adit. In addition, depending on the actual water inflow situation at the adit face 2, a second drainage pump group 9 can be installed at the adit face 2. The second drainage pump group 9 pumps the water inflow in front of the adit face to a temporary water collection pit 6 through corresponding pipelines. Preferably, the second drainage pump group 9 includes four sewage pumps with a power of 22 kW and a drainage capacity of 320 m3 / h per hour, and the number of sewage pumps increases with the increase of the on-site water inflow.

[0029] (3) When the excavation of branch tunnel 1 reaches 5m from the water-rich section at the tunnel face 2, a horizontal advance borehole is drilled on the tunnel face 2 to verify the specific geological conditions of the water-rich section. This avoids errors in judgment caused by uneven rock strata in geophysical exploration and provides accurate construction basis for subsequent grouting and water plugging. In step (3), if Figure 2 As shown, the horizontal advance exploratory boreholes include six horizontal exploratory boreholes 10 drilled along the excavation outline of the adit tunnel on the tunnel face. Specifically, the horizontal exploratory boreholes 10 are drilled using down-the-hole drills and located 1m inside the excavation outline of the adit tunnel. Each borehole has a diameter of Φ75mm, a spacing of 2m between boreholes, and a depth of 25m. The evenly distributed six horizontal exploratory boreholes 10 comprehensively verified the geological conditions of the water-rich section in front of the tunnel face 2. The actual positions of the horizontal exploratory boreholes 10 were determined on the tunnel face 2 using a total station and steel tape, and marked. Wet drilling was then used to drill the boreholes on the tunnel face 2 using a down-the-hole drill. Preferably, the outlet positions of the horizontal exploratory boreholes 10 were tested in a production-scale manner to accelerate the construction progress and meet the overall project schedule requirements.

[0030] (4) In order to locally restrict groundwater exposure, reduce the pumping intensity of the drainage system in the branch tunnel 1 at the tunnel face 2, and avoid occupying the construction process time separately, so as to avoid the groundwater exposure affecting the connection of each process in each cycle of construction at the tunnel face, according to the results of geophysical exploration and the drilling conditions of the horizontal advance exploration borehole at the tunnel face, advance fixed-point grouting is performed on the tunnel face 2, followed by excavation of the water-rich section of the branch tunnel; in step (4), the tunnel face 2 is temporarily sealed by advance fixed-point grouting to ensure that there is no stream of water exposure on the tunnel face 2 after excavation, thus preventing a significant impact on the excavation. If the water outflow of the tunnel face 2 does not decrease after the excavation of the water-rich section of the branch tunnel, advance fixed-point grouting is repeated.

[0031] Specifically, such as Figure 2 , 3 As shown, advanced fixed-point grouting includes the following sub-steps: (41) Orifice pipe installation: install a Φ60mm orifice pipe at the water outlet hole position of the horizontal pilot hole 10 on the drift face, where the water inflow is greater than 125L / min; preferably, the orifice pipe is a section of steel pipe welded with a flange, the steel pipe is 3m long, and a burst prevention device including an orifice and a valve structure is configured according to the construction requirements. Specifically, the orifice pipe is fixed in the corresponding water outlet hole position of the horizontal pilot hole by anchoring agent, and a stop valve is installed correspondingly.

[0032] (42) Drift face sealing: according to the nearby fissure development of the water outlet hole position of the horizontal pilot hole, C30 sprayed concrete is used to seal the water outlet fissure on the drift face 2, and the sealing thickness is 20cm. When the excavation of the drift 1 stops, the water outlet fissure on the drift face 2 is sealed, which not only ensures the stability of the drift face 2 and improves the construction safety, but also prepares for the subsequent advance point grouting and prevents the occurrence of slurry running.

[0033] (43) Grouting: using segmented forward grouting, cement single slurry is grouted into the orifice pipe at the water outlet hole position of the horizontal pilot hole 10, the length of each grouting segment is 5m, and the grouting pressure is 1.5-2MPa; the next grouting segment is constructed after the previous grouting segment is solidified for 24h. Preferably, the cement single slurry is prepared by using P.O42.5 cement with a strength grade, and the water-cement ratio of each grouting segment is adjusted in turn in stages as 2:1, 1:1, 0.8:1, and 0.5:1.

[0034] (44) When the single-hole grouting pressure of the water outlet hole position of the horizontal pilot hole 10 reaches the designed stable pressure value and maintains for 30min or the single-hole grouting volume is ≥2m³ / m, stop grouting; and use cement slurry with a water-cement ratio of 0.5:1 for pressure sealing. Preferably, the pressure sealing adopts 2MPa grouting pressure for static pressure sealing, and the sealing grouting time is 30min. In addition, when there is a large flow of underground water leakage around the grouting hole, supplementary grouting is performed according to the actual situation on site.

[0035] (5) In order to limit the water inflow of the whole excavated section of the drift, further reduce the drainage intensity of the drainage system of the drift, and prevent the water environment from being damaged and the drinking water of nearby residents from being significantly affected due to the decline of the underground water level, after excavating to a certain distance in the water-rich section of the drift 1, no-cover heavy grouting is performed on the excavated section of the drift, the water outlet points of the excavated section of the drift are sealed, the water inflow of the excavated section of the drift is reduced, and if the water inflow of the drift face 2 does not decrease, a horizontal pilot hole is re-performed on the drift face 2 and advance point grouting is performed at the corresponding water outlet hole position of the horizontal pilot hole, until the excavation of the drift is completed.

[0036] Specifically, the no-cover heavy grouting includes the following sub-steps: (51) Systematic grouting water resistance: as shown in Figure 4 , 5 , 6, a number of systematic grouting holes are arranged on the excavated section of the branch hole and along the direction of the branch hole, and the systematic grouting holes are grouted; each systematic grouting hole is arranged on the section of the excavated section of the branch hole with an interval of 3m. Specifically, each systematic grouting hole includes 8-9 grouting holes I 11 corresponding to drilling in the range of the edge crown of the excavated section of the branch hole in the shape of a plum blossom, and the drilling diameter of each grouting hole I 11 is Φ50mm, and the hole depth is 3.5m. Preferably, after drilling, air and water are used for flushing, the flushing water pressure is ≤1MPa, the air pressure is ≤0.5MPa, and the water is clear until the water is clear; at the same time, a single-point water pressure test is carried out according to 5% of the total number of holes. During grouting, according to the actual construction condition, cement and water glass double-liquid slurry are used for bare hole grouting, and the volume ratio of cement to water glass is 1:1, the water glass modulus is 2.6-2.8, the concentration is 35Be', and the grouting pressure is 2MPa; and according to the pure pressure type grouting method, the principle of arranging in sequence within the ring and encrypting between the rings for a single grouting hole is followed.

[0037] (52) Chemical grouting water resistance: as shown in Figure 7 , chemical grouting holes are drilled at each water outlet 13 and crack cavity 14 position of the excavated section of the branch hole, and the chemical grouting holes include 3-5 grouting holes II 12 drilled around the water outlet 13 and crack cavity 14 position. Specifically, the grouting hole II 12 is drilled by using YT-28 air drill and C25 self-feeding hollow anchor rod, the hole depth of each grouting hole II 12 is 1.5-3m, and the rod body end 1m range is not holed, and the rest of the position is provided with φ8 overflow hole. Then HCH-III type double-liquid reinforcing material and HCH-I type organic polymer grouting material are used for grouting treatment of the chemical grouting hole until the slurry overflows from the water outlet 13 and crack cavity 14 position of the excavated section of the branch hole, then the grouting is stopped, and the chemical grouting water resistance of the excavated section of the branch hole is completed.

[0038] Preferably, the HCH-III type double-liquid reinforcing material and the HCH-I type organic polymer grouting material are injected into the chemical grouting hole by using a pneumatic grouting pump. Among them, the HCH-III type double-liquid reinforcing material injected according to the ratio of 1:1 has good diffusivity under pressure due to its small density, can diffuse in the crack cavity 14 to form a high-strength and high-toughness polymer, and has good adhesion with the rock mass, high compressive and shear strength after adhesion, so as to achieve the effect of reinforcing and reinforcing the broken surrounding rock mass. The HCH-I type organic polymer grouting material is a single-liquid type organic polymer chemical grouting material, which uses air moisture as a curing agent, and immediately reacts to produce gas after encountering water, expands 10-20 times in volume and generates an elastic gel-like consolidated body that is insoluble in water and has a certain strength, thereby achieving the purpose of water stopping and leakage stopping.

[0039] Although some preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0040] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this application and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for treating water inrush in a tunnel adit, characterized in that, Includes the following steps: (1) The location and extent of the water-rich section of the unexcavated section of the branch tunnel were determined by geophysical exploration, and then the branch tunnel was excavated; (2) A drainage system is installed in the branch tunnel as the branch tunnel is excavated; the drainage system includes a temporary sump pit behind the tunnel face, several water tanks arranged along the tunnel excavation direction, and a water collection pit on both sides of each water tank. The temporary sump pit and each water tank are equipped with a drainage pump group for pumping water to the outside of the branch tunnel, and the water collection pit is equipped with a pumping pump group for pumping water to the corresponding water tank. (3) When the working face of the branch tunnel is 4 to 6 m away from the water-rich section, a horizontal advance borehole is constructed at the working face of the branch tunnel to obtain the geological information of the water-rich section. (4) After performing advanced fixed-point grouting at the outlet of the horizontal advanced exploration hole, the water-rich section of the branch tunnel is excavated. (5) After each certain distance is advanced in the excavation of the water-rich section of the branch tunnel, the excavated section of the branch tunnel is grouted without cover and the water output of the tunnel face is judged. If the water output does not decrease, step (4) is repeated until the excavation of the branch tunnel is completed.

2. The method for treating water inrush in tunnel adit according to claim 1, characterized in that, In step (3), the horizontal advance boreholes include a number of horizontal boreholes that are spaced apart along the inner side of the tunnel excavation outline.

3. The method for treating water inrush in tunnel adit according to claim 2, characterized in that, In steps (4) and (5), the advanced fixed-point grouting includes the following sub-steps: (41) Install the orifice pipe and the stop valve at the outlet position of each horizontal probe hole; (42) Use C30 shotcrete to seal the water-outflow cracks on the face of the tunnel, and the sealing thickness shall be at least 20cm; (43) Cement grout is injected into each of the orifice pipes using a segmented forward grouting method.

4. The method for treating water inrush in tunnel adit according to claim 1, characterized in that, In step (5), the uncovered grouting includes grouting a number of system grouting holes at intervals along the excavation direction of the branch tunnel in the excavated section, and grouting chemical grouting holes at each water outlet and crack cavity location in the excavated section of the branch tunnel.

5. The method for treating water inrush in tunnel adit according to claim 4, characterized in that, The system grouting holes include several grouting holes drilled in a quincunx pattern within the arch range of the excavated section of the branch tunnel. Each grouting hole is grouted with a cement and water glass grout.

6. The method for treating water inrush in tunnel adit according to claim 5, characterized in that, The chemical grouting holes include several grouting holes II drilled around each water outlet point and fissure cavity location in the excavated section of the branch tunnel. Each of the grouting holes II is grouted using HCH-III type dual-liquid reinforcement material and HCH-I type organic polymer grouting material.

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