A method for construction of a water channel tunnel for Xigeda geology

Abstract

The application discloses a kind of water channel tunnel construction methods for Xigeda geology, comprising the following steps: 1) optimization excavation method, control initial deformation;2) advance support is carried out, and vertical and horizontal anti-seepage structure construction is carried out;3) wet spraying process is used, and the quality of shotcrete construction is controlled;4) early closure of lining structure;5) perfect drainage system, ensure the stability of arch foot;6) complete inverted siphon construction in tunnel.The application is summarized through the above research on tunnel Xigeda stratum, a series of research results can be directly applied to the project;By changing construction technology, improving construction environment, improving work efficiency, saving construction cost, research results have very important significance for similar tunnel automation reduction, mechanization of construction technology of person's construction process, and have important role for improving tunnel construction technology management level, reducing construction safety risk, provide reference for similar engineering project construction.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of tunnel construction equipment, in particular to a water channel tunnel construction method for Xigeda geology. BACKGROUND

[0002] Water resources in the southwest region are relatively scarce, in order to ensure the production and living water of the people in the region, it is necessary to build reservoirs for water storage and water storage, and to build a hidden channel in the stratum is a necessary construction means for the construction of reservoirs in the southwest region. Xigeda geology is a unique fluvial facies sedimentary semi-rudite in southwest China, and the engineering geological conditions are poor. The geology is mainly (sandy) clay rock and fine sandstone or argillaceous siltstone interbedded, the bearing capacity is acceptable under natural little water condition, and the surrounding rock strength is obviously reduced when water is encountered, and it is difficult to be self-stable. The related research on the surrounding rock of Xigeda group stratum is just starting in China, and the construction of hidden channel needs to build water channel tunnel, how to construct water channel tunnel under Xigeda geology is a technical problem to be solved at present. SUMMARY

[0003] In view of the shortcomings of the prior art, the purpose of the present application is to provide a water channel tunnel construction method for Xigeda geology.

[0004] In order to achieve the above purpose, the present application realizes the following technical scheme: a water channel tunnel construction method for Xigeda geology, comprising the following steps:

[0005] (1) optimizing the excavation method to control the initial deformation;

[0006] (2) advance support is carried out, and vertical and horizontal anti-seepage structure construction is carried out;

[0007] (3) wet spraying process is adopted, and the construction quality of sprayed concrete is controlled;

[0008] (4) lining structure is closed early;

[0009] (5) perfect drainage system to ensure the stability of arch foot;

[0010] (6) the construction of inverted siphon pipe is completed in the tunnel.

[0011] The working principle of the technical scheme is that, according to the situation of Xigeda geology, the excavation method is optimized, the advance support is carried out, the anti-seepage structure is constructed, and the concrete spraying process is ensured, so as to ensure the safety of excavating water channel tunnel in Xigeda geology, and finally the inverted siphon pipe is used as the main water supply and drainage facility in the water channel tunnel. In this way, the water in the hidden channel will not affect the Xigeda geology in the tunnel, and the construction process of the hidden channel in the Xigeda geology is realized.

[0012] To better implement the method of the present invention, further, in step (1), the excavation method is the four-stage temporary inverted arch method, which uses an excavator to excavate. When approaching the tunnel outline, the excavation volume is controlled, and thick rubber sleeves are wrapped on both sides of the excavator bucket to reduce the collision effect of the excavator head on the surrounding rock and avoid initial deformation. The tunnel muck is loaded by a tracked muck loader and transported to the outside of the tunnel by dump truck.

[0013] In order to better implement the method of the present invention, further, in step (2), advanced support is carried out by grouting through advanced small guide pipes. In ordinary sections, single liquid grout is used, and in ascites sections, a two-liquid grout of cement and water glass is used for advanced support.

[0014] To better implement the method of the present invention, further, in step (2), vertical seepage prevention is carried out by constructing a concrete seepage barrier wall, and horizontal seepage prevention is carried out by laying seepage barrier panels and clay on the slope.

[0015] To better implement the method of the present invention, in step (3), the concrete used in the wet spraying process is finished concrete produced by the mixing plant.

[0016] To better implement the method of the present invention, further, in step (4), the specific process of early closure of the lining structure is as follows: During the excavation process, the secondary lining should closely follow the primary lining, and the distance between the secondary lining and the excavation face should be shortened as much as possible. If it is not possible to achieve one-time molding due to construction conditions, a temporary concrete inverted arch should be pre-set at the bottom of the upper step when pouring the arch, so that the arch can form a temporary complete support before the sidewall and inverted arch are completed. When the lower step construction is carried out, the temporary inverted arch is removed, and a permanent inverted arch is poured as soon as possible at the bottom of the tunnel to improve the stress conditions of the upper support structure in a timely manner.

[0017] To better implement the method of the present invention, further, in step (6), the inverted siphon is a PCCP pipe, and the specific process of completing the construction of the PCCP pipe in the tunnel is as follows:

[0018] (6.1) Construct a storage area for PCCP pipes, and prohibit stacking PCCP pipes;

[0019] (6.2) Excavation of the trench: Excavation is carried out by crushing with an excavator, and soil is piled on one side of the trench;

[0020] (6.3) Sand cushion layer filling: clean up the slag and fill the sand cushion layer, and compact it with a small tamping machine;

[0021] (6.4) pipeline installation: using 80t crawler crane to hoist the pipeline, using excavator to push or using jack and tensioner to slowly enter the socket, to complete the specific process of pipe installation, pipe arrangement, pipe stabilization, rubber ring installation and pipeline installation;

[0022] (6.5) water pressure test for PCCP pipe.

[0023] In order to better realize the method of the application, further, the water pressure test for PCCP pipe in step (6.5) includes three water pressure tests:

[0024] (6.5.1) the first joint pressure test is carried out immediately after the pipeline installation is completed, the purpose is to test the sealing of the joint, pressurized to the specified design pressure, keep 2min pressure not to drop, that is qualified, otherwise unqualified;

[0025] (6.5.2) the second joint pressure test, after every 3 PCCP pipes are installed, the first pipe joint is tested for the second time, the test method is the same as the first test;

[0026] (6.5.3) the third water pressure test is carried out after the pipe top backfilling is greater than 50cm, the test pressure is 1.2 times the working pressure, including pre-test stage and main test stage, the pre-test stage is stable for 30min, checking whether the pipeline joint and accessories have water leakage and damage; in the main test stage, stop water injection and pressure compensation for 15min, when the pressure drops by no more than 0.03MPa after 15min, the test pressure is increased to the working pressure and kept constant for 30min, and the appearance is checked, if there is no water leakage, the water pressure test is qualified.

[0027] Compared with the prior art, the application has the following advantages and beneficial effects:

[0028] Through the above research on Xigeda stratum of tunnel, a series of research results can be directly applied to the dependent project; by changing the construction technology, improving the construction environment, improving the work efficiency, saving the construction cost, the research results have very important significance for the similar tunnel automation and mechanization construction technology, and play an important role in improving the tunnel construction technology management level and reducing the construction safety risk, and bring Xigeda stratum tunnel construction experience for the construction of similar traffic facilities, and provide reference for similar engineering project construction. DETAILED DESCRIPTION

[0029] In order to make the purpose, process conditions and advantages of the present application more clear and explicit, the present application is further described in detail in combination with the following implementation examples, but the implementation examples of the present application are not limited thereto, various replacements and changes can be made according to the ordinary technical knowledge and conventional means in the art without departing from the above technical ideas of the present application, which should be included in the scope of the present application, the specific implementation examples described herein are only used to explain the present application and are not used to limit the present application.

[0030] Example 1

[0031] The present embodiment provides a water channel tunnel construction method for Xigeda geology, comprising the following steps:

[0032] (1) optimizing the excavation method to control the initial deformation;

[0033] (2) performing advanced support and constructing vertical and horizontal anti-seepage structures;

[0034] (3) adopting the wet spraying process and controlling the sprayed concrete construction quality;

[0035] (4) early closing of the lining structure;

[0036] (5) perfecting the drainage system to ensure the stability of the arch foot; Xigeda rock softens when meeting water, which not only causes the instability of the working face, but also leads to the muddy tunnel bottom, so that vehicles cannot pass through, therefore, the waterproof and drainage must be done well during construction; the sprayed concrete is closed in time after the tunnel is excavated, which can effectively control the water seepage, meanwhile, the water interception ditch and the water collecting well are arranged in the excavated section of the tunnel, and the temporary longitudinal drainage ditch is arranged at the arch foot of the tunnel. The drainage capacity is strengthened during construction to prevent the softening of the rock mass at the arch foot, the locking foot anchor pipe is increased, meanwhile, the longitudinal channel steel joist is added at the bottom of the arch, which can ensure the stability of the arch foot and reduce the deformation of the initial support;

[0037] (6) completing the construction of the inverted siphon in the tunnel.

[0038] Example 2

[0039] The present embodiment further limits the excavation method on the basis of the above embodiment, in the step (1), the excavation method is the four-step temporary inverted arch method, the excavator is used for excavation, when approaching the contour line of the tunnel, the excavated amount is controlled, the thick rubber sleeve is wrapped on both sides of the excavator bucket to reduce the impact of the excavator head on the surrounding rock, to avoid the initial deformation, the tunnel hole slag is loaded by the crawler-type slag loader and transported outside the tunnel hole by the slag truck. For Xigeda stratum, it is the key to the construction to control the disturbance to the surrounding rock and reduce the initial deformation of the surrounding rock while doing a good job in the prevention and control of underground water during the excavation process. The other parts of the present embodiment are the same as those of the above embodiment, which will not be described here.

[0040] Example 3

[0041] The embodiment is further limited on the basis of the above-mentioned embodiment, and the step (2) is further limited. In the step (2), the advanced support is performed by the advanced small catheter grouting. The single liquid grout is used in the ordinary section, and the double liquid grout mixed with cement and water glass is used in the ascites section to perform the advanced support. The advanced small catheter grouting of the advanced support can improve the physical properties of the soil. In the surrounding rock with short self-stabilization time and weak self-supporting capacity, the supporting capacity of the tunnel can be greatly enhanced. In the construction, the small pipe shed system is formed together with the steel frame to support the rock wall, which is one of the most effective auxiliary construction methods of the tunnel engineering in the adverse geological conditions. The small catheter is designed. The advanced small catheter of the tunnel is a seamless steel pipe with a diameter of 42 mm, a wall thickness of 3.5 mm, an external insertion angle of 10°-12°, a single length of 4.5 m, and a lap length of 1 m between adjacent two cycles. The grouting hole is drilled in the front part of the small catheter, the hole diameter is 6-8 mm, the interval is 10-20 cm, the holes are arranged in the shape of a plum blossom, the front end is processed into a conical shape, and the tail part is provided with a non-drilling section with a length of not less than 30 cm as a grout stopping section. The single liquid grout is used in the ordinary section, and the cement-water glass double liquid grout is used in the water-rich section. The strength grade of the grout is not less than M10. The characteristics of the single liquid grout mainly reflect the consistency, setting time and water-cement ratio of the grout, which can be 0.8:1-2:1. The characteristics of the double liquid grout mainly reflect the viscosity, granularity and gel time of the grout, and the water-cement ratio can be 0.8:1-1.5:4. The volume ratio of the cement grout to the water glass is generally 1:0.3-1:1. The grouting matters needing attention are as follows: ① After the small catheter is installed, the hole and the surrounding cracks are sealed with cement, and if necessary, the excavation surface is sprayed with 5-10 cm of concrete as a grout stopping layer; ② The grout should be filtered through a filter screen to prevent foreign matter from entering the grouting pump or the small catheter; ③ When grouting, the non-leakage hole should be grouted first, and then the leakage hole; ④ The grouting pressure should be strictly controlled. The grouting machine pressure should be matched with the design pressure. When the design pressure is reached, the pressure should be stabilized for 10 min; ⑤ During the grouting process, the changes of the grouting pressure and the grouting pump discharge amount should be observed in time to analyze the grouting condition, prevent the grout from running, leaking and blocking the pipe, and record the grouting to analyze the grouting effect. The other parts of the embodiment are the same as those of the above-mentioned embodiment, and will not be repeated here.

[0042] Embodiment 4:

[0043] The embodiment is further limited on the basis of the above-mentioned embodiment, and the vertical and horizontal anti-seepage structure is constructed. In the step (2), the vertical anti-seepage is constructed by constructing a concrete anti-seepage wall, and the horizontal anti-seepage is constructed by laying an anti-seepage panel and clay on the slope. According to relevant regulations and construction manuals, the concrete anti-seepage wall is a continuous underground wall constructed by continuously drilling and grooving in the loose water-permeable foundation or earth-rock dam (weir) with mud slurry, pouring concrete or backfilling other anti-seepage materials to form a continuous wall for anti-seepage. It can be almost adapted to various geological conditions, including loose silt to dense sand and gravel, even boulders and rock layers (the bedrock mainly refers to the bedrock with relatively weak strength, including weathered rock mass). The anti-seepage panel and clay are laid on the Xigeda slope to reduce seepage and protect the slope. The treatment range and scheme are as follows: the reinforced concrete anti-seepage panel is laid in the range of the upstream side of the core wall base, above the slope elevation of 1270.00 m, and within the dam body filling contour line; the clay is laid in the range of above the dead water level, below the slope top elevation of 1307.00 m, and about 100 m in front of the dam; the curtain grouting anti-seepage is adopted near the gabbro boundary of Xigeda at the elevation of 1270.00 m, and the horizontal paving + clay cutoff trench is adopted for the Xigeda stratum. The upstream clay paving excavation and filling slope ratio is the same as that of the panel section, the planar arrangement is circular arc, the surface adopts a filter layer and a prefabricated six-rib block slope protection. The vertical thickness of the top of the clay paving is 1.83 m, and the vertical thickness of the bottom of the reservoir is 6.69 m. The horizontal paving is 15 m wide and 7 m thick, and the slope outside the paving is 1:4. The top of the slope protection is flush with the top of the dam, and a 20 cm thick mud and stone road is arranged at an elevation of 1307.00 m. The other parts of the embodiment are the same as those of the above-mentioned embodiment, and will not be repeated here.

[0044] Embodiment 5

[0045] The embodiment is further limited on the basis of the above-mentioned embodiment, and in the step (3), the concrete used in the wet spraying process is the finished product concrete produced by the mixing station. Compared with other spraying processes, the wet spraying process has the advantages of easy guarantee of the quality of the sprayed concrete raw materials, small concrete rebound rate, good concrete compactness and durability. During construction, the large wet spraying mechanical hand can fully play the advantages of the wet spraying process. The wet spraying mechanical hand is equipped with a stable air pressure air compressor for spraying, which can improve the compactness and homogeneity of the concrete. The wet spraying mechanical hand has a spraying capacity of more than 203 per hour, greatly shortens the operation cycle time, effectively constrains the development of rock deformation by quickly sealing the rock surface, improves the stress state of the surrounding rock, and enhances the stability of the surrounding rock. The other parts of the embodiment are the same as those of the above-mentioned embodiment, and will not be repeated here.

[0046] Embodiment 6

[0047] The embodiment is further limited on the basis of the above-mentioned embodiment, and the specific process of early closure of the lining structure in the step (4) is as follows: in the excavation process, the secondary lining should follow the primary lining and the interval between the secondary lining and the excavation working face should be shortened as much as possible. If the construction condition restricts the realization of one-time forming, a temporary concrete inverted arch should be set at the bottom of the upper step during the pouring of the arch part, so that a temporary complete support body is formed before the side wall and the inverted arch are completed. When the lower step construction is carried out, the temporary inverted arch is removed, and the permanent inverted arch is poured at the tunnel bottom as soon as possible, so as to timely improve the stress condition of the upper support structure. The deformation of the surrounding rock mainly occurs in the time period from the excavation of the working face to the completion of the support of the lower step. The deformation distance of the surrounding rock is mainly close to the working face, especially the position of the middle step, so the deformation mainly occurs in the construction and erection stage of the excavation arch frame. The reasons are mainly that the Xigeda stratum is soft, the steel frame is temporarily suspended due to the excavation of the middle step and the lower step, and the support force at the arch foot is insufficient, which causes large settlement. When the Xigeda stratum containing water is constructed, the working face cannot be self-stable, and the excavation principle of small section and less disturbance must be followed. Steady drilling and steady shooting, no progress is taken, the safety step distance is shortened as much as possible, the ring is closed as soon as possible, and it is proved that as long as the ring is closed and not disturbed, the surrounding rock will basically tend to be stable. The other parts of the embodiment are the same as those of the above-mentioned embodiment, and will not be described here.

[0048] The embodiment is further limited on the basis of the above-mentioned embodiment, and the specific process of early closure of the lining structure in the step (4) is as follows: in the excavation process, the secondary lining should follow the primary lining and the interval between the secondary lining and the excavation working face should be shortened as much as possible. If the construction condition restricts the realization of one-time forming, a temporary concrete inverted arch should be set at the bottom of the upper step during the pouring of the arch part, so that a temporary complete support body is formed before the side wall and the inverted arch are completed. When the lower step construction is carried out, the temporary inverted arch is removed, and the permanent inverted arch is poured at the tunnel bottom as soon as possible, so as to timely improve the stress condition of the upper support structure. The deformation of the surrounding rock mainly occurs in the time period from the excavation of the working face to the completion of the support of the lower step. The deformation distance of the surrounding rock is mainly close to the working face, especially the position of the middle step, so the deformation mainly occurs in the construction and erection stage of the excavation arch frame. The reasons are mainly that the Xigeda stratum is soft, the steel frame is temporarily suspended due to the excavation of the middle step and the lower step, and the support force at the arch foot is insufficient, which causes large settlement. When the Xigeda stratum containing water is constructed, the working face cannot be self-stable, and the excavation principle of small section and less disturbance must be followed. Steady drilling and steady shooting, no progress is taken, the safety step distance is shortened as much as possible, the ring is closed as soon as possible, and it is proved that as long as the ring is closed and not disturbed, the surrounding rock will basically tend to be stable. The other parts of the embodiment are the same as those of the above-mentioned embodiment, and will not be described here.

[0049] Embodiment 7:

[0050] The embodiment is further limited on the basis of the above-mentioned embodiment, and the specific process of early closure of the lining structure in the step (4) is as follows: in the excavation process, the secondary lining should follow the primary lining and the interval between the secondary lining and the excavation working face should be shortened as much as possible. If the construction condition restricts the realization of one-time forming, a temporary concrete inverted arch should be set at the bottom of the upper step during the pouring of the arch part, so that a temporary complete support body is formed before the side wall and the inverted arch are completed. When the lower step construction is carried out, the temporary inverted arch is removed, and the permanent inverted arch is poured at the tunnel bottom as soon as possible, so as to timely improve the stress condition of the upper support structure. The deformation of the surrounding rock mainly occurs in the time period from the excavation of the working face to the completion of the support of the lower step. The deformation distance of the surrounding rock is mainly close to the working face, especially the position of the middle step, so the deformation mainly occurs in the construction and erection stage of the excavation arch frame. The reasons are mainly that the Xigeda stratum is soft, the steel frame is temporarily suspended due to the excavation of the middle step and the lower step, and the support force at the arch foot is insufficient, which causes large settlement. When the Xigeda stratum containing water is constructed, the working face cannot be self-stable, and the excavation principle of small section and less disturbance must be followed. Steady drilling and steady shooting, no progress is taken, the safety step distance is shortened as much as possible, the ring is closed as soon as possible, and it is proved that as long as the ring is closed and not disturbed, the surrounding rock will basically tend to be stable. The other parts of the embodiment are the same as those of the above-mentioned embodiment, and will not be described here.

[0051] (6.1) Build the placing site of the PCCP pipe, and prohibit stacking the PCCP pipes;

[0052] (6.2) Perform trench stone excavation: adopt the excavator for crushing excavation, and stack the earth on one side of the trench;

[0053] (6.3) Sand cushion filling: clean the slag, fill the sand cushion, and adopt the small tamper to tamp;

[0054] (6.4) Perform pipe installation: adopt the 80t crawler crane to hoist the pipe, adopt the excavator to push or adopt the jack and the tensioner to slowly enter the socket, complete the specific process of pipe lowering, pipe arrangement, pipe stabilization, rubber ring installation, and pipe installation;

[0055] (6.5) Perform water pressure test on the PCCP pipe. The other parts of the embodiment are the same as those of the above-mentioned embodiment, and will not be described here.

[0056] Embodiment 8:

[0057] The embodiment is further limited to the specific process of the water pressure test of the PCCP pipe based on the above embodiment, and the water pressure test of the PCCP pipe in the step (6.5) includes three water pressure tests:

[0058] (6.5.1) The first joint pressure test is performed immediately after the pipeline installation, and the purpose is to test the sealing of the joint, and the pressure is increased to the specified design pressure, and the pressure is not reduced for 2 min, which is qualified, otherwise unqualified;

[0059] (6.5.2) The second joint pressure test is performed after every 3 PCCP pipes are installed, and the first pipe joint of the previous installation is subjected to the second interface water pressure test, and the test method is the same as the first test;

[0060] (6.5.3) The third water pressure test is performed after the pipe top backfilling is greater than 50 cm, the test pressure is 1.2 times the working pressure, and the test pressure is divided into a pre-test stage and a main test stage, wherein the pre-test stage is stabilized for 30 min, and the pipeline interface and accessories are checked for water leakage and damage; in the main test stage, the water injection and pressure compensation are stopped for 15 min, when the pressure drops by no more than 0.03 MPa after 15 min, the test pressure is increased to the working pressure and kept constant for 30 min, and the appearance is checked, if there is no water leakage, the water pressure test is qualified. The other parts of the embodiment are the same as the above embodiment, and will not be repeated here.

[0061] Although the embodiments of the present application have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A method for constructing a canal tunnel in the geological conditions of Xigeda, characterized in that, Includes the following steps: (1) Optimize excavation methods and control initial deformation; (2) Carry out advance support and construct vertical and horizontal seepage prevention structures; (3) Wet spraying process is adopted and the construction quality of sprayed concrete is controlled; (4) The lining structure should be closed as early as possible; (5) Improve the drainage system to ensure the stability of the arch frame and arch foot; (6) Construction of the inverted siphon is completed inside the tunnel; the inverted siphon is a PCCP pipe, and the specific process of completing the construction of the PCCP pipe inside the tunnel is as follows: (6.1) Construct a storage area for PCCP pipes, and prohibit stacking PCCP pipes; (6.2) Excavation of the trench: Excavation is carried out by crushing with an excavator, and soil is piled on one side of the trench; (6.3) Sand cushion layer filling: clean up the slag and fill the sand cushion layer, and compact it with a small tamping machine; (6.4) Pipeline installation: Use an 80t crawler crane to lift the pipeline. During installation, use an excavator to push or use jacks and pullers to slowly insert the pipe into the socket, and complete the specific process of laying the pipe, arranging the pipe, stabilizing the pipe, installing the rubber ring, and installing the pipeline. (6.5) Perform a hydrostatic test on the PCCP pipe; the hydrostatic test of the PCCP pipe includes three hydrostatic tests: (6.5.1) The first joint pressure test shall be carried out immediately after the pipeline installation is completed. The purpose is to check the sealing performance of the joint. The pressure shall be increased to the specified design pressure and maintained for 2 minutes without pressure drop. If the pressure does not drop, it is considered qualified; otherwise, it is unqualified. (6.5.2) Second joint pressure test: After every 3 sections of PCCP pipe are installed, a second joint water pressure test shall be conducted on the first pipe joint that was previously installed. The test method shall be the same as the first test. (6.5.3) The third hydrostatic test shall be carried out after the backfill on the top of the pipe is >50cm. The test pressure shall be 1.2 times the working pressure. The test shall be divided into a pre-test stage and a main test stage. In the pre-test stage, the pressure shall be stabilized for 30 minutes and the pipe joints and fittings shall be checked for leaks or damage. In the main test stage, the water injection shall be stopped and the pressure shall be stabilized for 15 minutes. When the pressure drop does not exceed 0.03MPa after 15 minutes, the test pressure shall be reduced to the working pressure and kept constant for 30 minutes. A visual inspection shall be carried out. If there are no leaks, the hydrostatic test shall be qualified.

2. The method for constructing a canal tunnel for the geology of Xigeda according to claim 1, characterized in that, In step (1), the excavation method is the four-stage temporary inverted arch method, which uses an excavator to excavate. When the excavation volume is close to the tunnel outline, the excavation volume is controlled. Thick rubber sleeves are wrapped on both sides of the excavator bucket to reduce the impact of the excavator head on the surrounding rock and avoid initial deformation. The tunnel muck is loaded by a tracked muck loader and transported to the outside of the tunnel by dump truck.

3. A method for constructing a canal tunnel for the geology of Xigeda according to claim 1 or 2, characterized in that, In step (2), advanced support is carried out by grouting through advanced small guide pipes. Single-liquid grout is used in ordinary sections, and double-liquid grout mixed with cement and water glass is used in ascites sections for advanced support.

4. A method for constructing a canal tunnel for the geology of Xigeda according to claim 1 or 2, characterized in that, In step (2), vertical seepage prevention is achieved by constructing a concrete seepage barrier wall, and horizontal seepage prevention is achieved by laying seepage barrier panels and clay on the slope.

5. A method for constructing a canal tunnel for the geology of Xigeda according to claim 1 or 2, characterized in that, In step (3), the concrete used in the wet spraying process is finished concrete produced by the mixing plant.

6. A method for constructing a canal tunnel for the geology of Xigeda according to claim 1 or 2, characterized in that, In step (4), the specific process of early closure of the lining structure is as follows: during the excavation process, the secondary lining should closely follow the primary lining and the distance between the secondary lining and the excavation face should be shortened as much as possible. If it is not possible to achieve one-time molding due to the limitations of construction conditions, a temporary concrete inverted arch should be pre-set at the bottom of the upper step when the arch is poured so that the arch can form a temporary complete support before the side wall and inverted arch are completed. When the construction of the lower step is carried out, the temporary invert arch is removed and a permanent invert arch is poured at the bottom of the tunnel as soon as possible to improve the stress conditions of the upper support structure in a timely manner.