Method for treating relatively concentrated water inflow in underground engineering projects

Abstract

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Description

Technical Field The present invention relates to the field of groundwater treatment methods, specifically to a method for treating relatively concentrated water inrushes in underground engineering projects. Background Technology When excavating deep foundation pits, tunnels, roadways, shafts, and basements, encountering water-rich rock layers can frequently lead to sudden water inrush accidents if detection and treatment are not timely. This can cause direct flooding of underground spaces or result in significant energy waste and economic losses due to prolonged and forceful drainage. For example, in a deep foundation pit under construction for Metro Line 4 in Xuzhou, Jiangsu Province, China, the water outflow from the limestone base reached 1500 m3 / h, with daily drainage reaching 36,000 m3, and daily drainage costs reaching RMB 36,000. Currently, there are several methods for dealing with large-scale water inrushes caused by accidental exposure of water-bearing bodies in underground engineering projects: Firstly, grouting pipes are directly buried in the outlet and channel. After the grouting pipes are solidified and stable, grout is injected directly through them to seal the water inrush. This method is suitable for water inrushes caused by low water pressure, regular outlets, and rock formations with high strength and stability. However, for cases with relatively low rock strength, if the grouting pipes are closed before grouting, the rising water pressure at the outlet may directly cause the grouting pipes to loosen or even be pulled out, and may also cause rock formation damage, creating new water inrush points. Secondly, as disclosed in Chinese Patent 2025279637   09 Dec 2025 Application No. 2019108697755, a method for sealing high-pressure, high-flow-rate water inrushes in mines, involves first constructing a drainage borehole on the water outlet channel, where the water is drained... In some cases, the outlet is then sealed with grout. This method requires a clear understanding of the grouting channel. Thirdly, if the Chinese patent application number 2010106164844 discloses a method for constructing a static cement grouting pad, or the Chinese patent application number 2015104209843 discloses a method for constructing an underwater grouting pad for inclined wells, then, if the underground project is flooded, a concrete grouting pad of a certain thickness is poured underwater. After the grouting pad has fully cured, the accumulated water is pumped out, and then grouting is performed on the grouting pad to stop the water flow. This method is mainly suitable for underground projects with small foundations. Furthermore, the poured grouting pad often needs to be relatively thick, and after the grouting pad achieves its effect, subsequent sealing of the outlet points is required. Summary of the Invention To address the aforementioned technical shortcomings, the purpose of the present invention is to provide a method for treating relatively concentrated water inflow in underground engineering projects. The method fully considers the characteristics of the water outlet, geological and hydrogeological conditions, and is mainly applicable to the treatment of water inflow points in underground engineering projects with relatively concentrated water outlets, weak rock strata, large underground engineering foundations, and relatively shallow burial. It features simple principles, safety and reliability, and convenient operation. To solve the above-mentioned technical problems, the present invention adopts following technical solution: The present invention provides a method for controlling concentrated water inflow in underground engineering projects, comprising following steps: 2025279637   09 Dec 2025 S1-drainage from underground engineering projects to expose water outlets, wherein accumulated and inflowing water is continuously pumped out from underground engineering projects by using a drainage system to fully expose water outlets at foundation; S2-cleaning the foundation of the underground engineering projects, wherein after continuously pumping accumulated and inflowing water to the foundation, the water outlets at the foundation are cleaned to be fully exposed, thereby allowing observation of locations, volumes, forms, and shapes of the water outlets; S3-adjusting the water outlets and detecting extension directions of water outlet channels, wherein the water outlets are appropriately adjusted, so as to detecting extension directions of water outlet channels from the water outlets inwards; S4-using pipes for water collection and diversion, wherein water diversion pipelines of certain depths are inserted into the water outlets for water collection and diversion, outer diameters of the water diversion pipelines are ensured to match the water outlets as closely as possible, and then gaps between the water diversion pipelines and the water outlets are effectively filled to ensure that there is no leakage and water is completely concentrated and flows out through the water diversion pipelines, which requires diverting water from the water outlets; S5-connecting water diversion pipelines, wherein the water diversion pipelines are connected to ensure that lengths of the water diversion pipelines is greater than burial depths of underground engineering sites and greater than water level of an outlet water source, and connecting tail end portions of the water diversion pipelines to suspension ropes; S6- flooding the underground space: stopping drainage from the underground 2025279637   09 Dec 2025 engineering projects, and gradually flooding underground space by using water from the underground engineering projects until water level is completely stable; S7-raising the tail end portions of the water diversion pipelines above water surface: using suspension ropes to raise the water diversion pipelines above the water surface; S8- using the drainage pipes for grouting, wherein the water diversion pipelines to are connected to grouting pipelines for grouting, and grout enters water diversion channels through the water diversion pipelines, thus sealing the water outlets and the water diversion channels; and S9- pumping out water in the underground space: after the grout has fully solidified, pumping out all the water in the underground space, cutting off the water diversion pipelines, and completing the sealing of water inflow points in the underground engineering projects. Preferably, in step S1, an actual drainage capacity of the drainage system shall be greater than inflow rates of the underground engineering projects, and a pumping head shall be greater than burial depths of the underground engineering projects. Preferably, in step S2, the water outlets are modified to circular or elliptical shapes. Preferably, in steps S4-S7, the water diversion pipelines are always kept open. Preferably, in step S4, cotton yarn or woven bags soaked in flocculating grout are used to effectively fill the gaps between the water diversion pipelines and the water outlets. Preferably, in step S4, the flocculating grout is selected as cement-water glass 2025279637   09 Dec 2025 two-component grout or a two-component urea-formaldehyde resin grout. Preferably, in step S8, ordinary cement grout or cement-water glass double-liquid grout is used for grouting. The beneficial effects of the present invention are as follows: The core of the present invention is that after using a water-conducting pipeline to guide and collect water at the water outlet, the underground space is flooded by the water itself flowing out of the underground engineering. Thus, when using the water-conducting pipeline for grouting treatment, the accumulated water in the underground space can partially offset the grouting pressure, relatively reducing the effect of the grouting pressure on the rock strata near the water outlet. This ensures effective grout diffusion while preventing damage to the underlying rock strata, thereby guaranteeing the safety and effectiveness of the treatment. Brief Description of the Drawings To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 is a schematic diagram of the water outlet point exposed after drainage of the underground engineering provided in an embodiment of the present invention. Figure 2 is a schematic diagram of the connecting water guide pipeline provided in an embodiment of the present invention. Figure 3 is a schematic diagram of grouting of the water guide pipeline provided in an 2025279637   09 Dec 2025 embodiment of the present invention. Figure 4 is a schematic diagram of the underground space after water is pumped out provided in an embodiment of the present invention. Specific Embodiments The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The present embodiment provides a method for treating relatively concentrated water inflow in underground engineering projects. The specific steps are as follows: © Draining water from the underground engineering projects to expose the water outlet point (see Figure 1) ^ © Cleaning the foundation of the underground engineering projects ^ © Repairing the water outlets and detecting the extension direction of the water outlet channels ^ © Using pipelines for water collection and diversion ^ @ Connecting the water diversion pipeline (see Figure 2 for water diversion pipeline installation) ^ @ Submerging the underground space ^ © Raising the end of the water diversion pipeline out of the water surface ^ ® Grouting using the water diversion pipeline (see Figure 3) ^ © Pumping out the accumulated water in the underground space (see Figure 4). Taking the tunnel boring machine (TBM) launching and receiving pit at the intersection of Metro Line 4 in a certain city in China as an example, the pit is 30 m deep and 40 m long and wide. The upper 10m is a loose layer, and the lower 20 m is a limestone layer. The limestone layer has strong water-bearing capacity and well-developed solution fissures. When the pit was constructed to a depth of 30m, 2025279637   09 Dec 2025 the structure of the base rock layer was poor, and three main water inflow points were exposed. All of them were large solution fissures, which were approximately elliptical in shape. The total water inflow was 1500 m3 / h, and the daily drainage reached 36000 m3, with a daily drainage cost of RMB 36,000. First, after draining the gushing and accumulated water from the foundation pit, personnel and machinery entered the site to survey and modify the water outlet. The modification was primarily done using a pneumatic drill, shaping it into an approximately circular shape. Rebar was inserted into the outlet to probe the direction of the water channel. It was found that the water channel extended in different directions, but overall it was relatively regular and the channel was unobstructed. A thick-walled corrugated pipe with a diameter basically matching the water outlet was used as the water guide pipe. Corrugated pipes of corresponding diameters of 2.1 m, 1.5 m, and 1.4 m were respectively lowered into the three water outlets. The gap between the corrugated pipe and the water outlet was densely filled with waste cement woven bags soaked in cement-water glass slurry, with a filling depth exceeding 1.0m. Then, the corrugated pipe was connected to a length of 40 m, with a steel wire rope connected to the end of the corrugated pipe to the ground. Approximately 50 hours after the foundation pit drainage was stopped, the water level in the foundation pit stabilized, with a water depth reaching 25 m. The end of the corrugated pipe was pulled out of the water surface using a steel wire rope connected to its tail and fixed at the edge of the foundation pit. The grouting pump was connected to the corrugated pipe, and grouting was performed on each corrugated pipe individually (see figure 3, grouting inside the guide pipe). Initially, a single-component cement grout was injected. After deducting the volume of the grout inside the corrugated pipe, the amount of cement grout used at a single water point reached 15 m3. Then, approximately 5% of the cement grout volume of water 2025279637   09 Dec 2025 glass was added. Grouting was stopped after the grout volume at each water point reached 10 m3, as it was predicted that the grout would block the water outlet channel for more than 20m. Referring to figure 4, 48 hours after the grouting was completed and the grout had fully solidified, the water in the foundation pit was pumped out and drained. No water was found coming out of the bottom of the well. The corrugated pipe that guides the water was cut off, and the treatment of multiple relatively concentrated water inflows in the foundation pit was completed. The present invention uses a water-conducting pipeline to guide and collect water at the water outlet point, and then uses the water from the underground engineering itself to flood the underground space. In this way, when using the water-conducting pipeline for grouting treatment, the water accumulation in the underground space can offset the grouting pressure to a certain extent, thereby reducing the effect of the grouting pressure on the rock strata near the water outlet point. This ensures effective diffusion of the grout while preventing damage to the base rock strata, thus ensuring the safety and effectiveness of the treatment. Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method for controlling concentrated water inflow in underground engineering projects, comprising following steps:S1-drainage from underground engineering projects to expose water outlets, wherein accumulated and inflowing water is continuously pumped out from underground engineering projects by using a drainage system to fully expose water outlets at foundation;S2-cleaning the foundation of the underground engineering projects, wherein after continuously pumping accumulated and inflowing water to the foundation, the water outlets at the foundation are cleaned to be fully exposed, thereby allowing observation of locations, volumes, forms, and shapes of the water outlets;S3-adjusting the water outlets and detecting extension directions of water outlet channels, wherein the water outlets are appropriately adjusted, so as to detecting extension directions of water outlet channels from the water outlets inwards;S4-using pipes for water collection and diversion, wherein water diversion pipelines of certain depths are inserted into the water outlets for water collection and diversion, outer diameters of the water diversion pipelines are ensured to match the water outlets as closely as possible, and then gaps between the water diversion pipelines and the water outlets are effectively filled to ensure that there is no leakage and water is completely concentrated and flows out through the water diversion pipelines, which requires diverting water from the water outlets;S5-connecting water diversion pipelines, wherein the water diversion pipelines are connected to ensure that lengths of the water diversion pipelines is greater than burial depths of underground engineering sites and greater than water level of an outlet water source, and connecting tail end portions of the water diversion2025279637   09 Dec 2025pipelines to suspension ropes;S6- flooding the underground space: stopping drainage from the underground engineering projects, and gradually flooding underground space by using water from the underground engineering projects until water level is completely stable;S7-raising the tail end portions of the water diversion pipelines above water surface: using suspension ropes to raise the water diversion pipelines above the water surface;S8- using the drainage pipes for grouting, wherein the water diversion pipelines to are connected to grouting pipelines for grouting, and grout enters water diversion channels through the water diversion pipelines, thus sealing the water outlets and the water diversion channels; andS9- pumping out water in the underground space: after the grout has fully solidified, pumping out all the water in the underground space, cutting off the water diversion pipelines, and completing the sealing of water inflow points in the underground engineering projects.

2. The method for controlling concentrated water inflow in underground engineering projects according to claim 1, wherein in step S1, an actual drainage capacity of the drainage system shall be greater than inflow rates of the underground engineering projects, and a pumping head shall be greater than burial depths of the underground engineering projects.

3. The method for controlling concentrated water inflow in underground engineering projects according to claim 1, wherein in step S2, the water outlets are modified to circular or elliptical shapes.2025279637   09 Dec 20254. The method for controlling concentrated water inflow in underground engineering projects according to claim 1, wherein in steps S4-S7, the water diversion pipelines are always kept open.

5. The method for controlling concentrated water inflow in underground engineering projects according to claim 1, wherein in step S4, cotton yarn or woven bags soaked in flocculating grout are used to effectively fill the gaps between the water diversion pipelines and the water outlets.

6. The method for controlling concentrated water inflow in underground engineering projects according to claim 5, wherein in step S4, the flocculating grout is selected as cement-water glass two-component grout or a two-component urea-formaldehyde resin grout.

7. The method for controlling concentrated water inflow in underground engineering projects according to claim 1, wherein ordinary cement grout or cement-water glass double-liquid grout is used for grouting.

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