Cooperative grouting treatment method for large-diameter shield tunnel in upper-soft lower-hard stratum

Abstract

The invention provides a cooperative grouting disposal method for a large-diameter shield tunnel in an upper-soft and lower-hard stratum, and relates to the technical field of tunnel grouting processes. The cooperative grouting disposal method for the large-diameter shield tunnel in the upper-soft and lower-hard stratum comprises the construction steps that S1, the geology of the grouting position is investigated; S2, grouting parameters are managed, including slurry preparation, S3, grouting equipment debugging, S4, grouting, S5, grouting working condition analysis, S6, secondary grouting and S7, the grouting effect is judged. According to the prepared superfine cement and water glass double-liquid slurry, the solidification time and the volatilization strength of the grouting liquid can be changed through the additive, so that the grouting liquid is suitable for various complicated geological conditions and engineering requirements of shield tunnels, the gelation time is adjusted according to specific conditions, and the optimal grouting effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel grouting technology, and in particular to a coordinated grouting treatment method for a large-diameter shield tunnel in an upper soft and lower hard stratum. Background Art

[0002] The shield method is an advanced construction method for building tunnels in soft soil foundations. Shield tunnels have been widely used in the construction of subways and sewage pipes. Grouting technology is an engineering technology with strong practicality and wide application range. It has been widely used in various fields such as mines, underground buildings, dams, tunnels, subways, bridges and civil engineering. The upper soft and lower hard strata refer to the complex strata encountered during the construction of shield tunnels, with the upper part of the strata being soft soil layers (such as silt, silty clay, etc.) and the lower part being hard rocks (such as granite, limestone, etc.). Grouting treatment is a key link in the construction of large-diameter shield tunnels in such strata.

[0003] Grouting is mainly used to fill the gap between the pipe segment and the stratum after shield excavation, control stratum deformation, and prevent ground subsidence and other problems. Therefore, the present invention proposes a collaborative grouting treatment method for large-diameter shield tunnels with soft upper and hard lower strata, which makes the collaborative grouting process of large-diameter shield tunnels with soft and hard lower strata more efficient and more flexible to cope with different geological environments. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a coordinated grouting treatment method for a large-diameter shield tunnel with soft upper and hard lower strata. Through the coordination of synchronous grouting and secondary grouting, the deformation of the stratum can be effectively controlled at different stages. The synchronous grouting can timely fill the gap between the pipe segment and the stratum during the shield excavation process, and provide preliminary support for the stratum, thereby achieving the advantage of effectively controlling the terrain. At the same time, a multi-tube grouting method is adopted, and multiple grouting pumps are used for synchronous grouting, which can not only improve the grouting efficiency, but also more precisely control the grouting efficiency, and facilitate the layered control of the grouting pressure, so as to avoid excessive squeezing of the slurry on the soft soil to cause soil splitting, and also ensure that the slurry can be effectively injected into the cracks of the rock. It is more suitable for grouting operations in a layered geological soil environment with soft upper and hard lower stratification.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: The coordinated grouting treatment method for a large-diameter shield tunnel in upper soft and lower hard strata comprises the following steps: S1: Investigate the geology of the grouting site and prepare for grouting construction; S2: Grouting parameter management, including slurry modulation, and modulation of ultra-fine cement-water glass double liquid slurry according to the upper soft and lower hard strata; S3: Debugging of grouting equipment, and evenly burying grouting conduits in the through holes of large-diameter shield tunnels; S4: Grouting: perform pressure injection and synchronous grouting on multiple grouting holes pre-set at the shield tail, and set a pressure divider at the outlet of each grouting hole to control the grouting pressure between 0.1-0.5MPa; S5: Grouting condition analysis: timely monitoring and early warning as well as grouting control are carried out according to the deformation monitoring results of the segment lining in the tunnel and the deformation of the ground and surrounding buildings, and timely solutions are provided when any problems are found; S6: Secondary grouting: according to the analysis of grouting conditions, the grouting parameters are adjusted. If the synchronous grouting is found to be insufficient, secondary grouting is carried out through the grouting holes in the middle of the segment to fill the unfilled part and the reduced volume part of the primary grouting. S7: Determination of grouting effect. After the grouting stops, the grouting effect in the tunnel is monitored, analyzed and evaluated to determine whether it meets the standards. If the tunnel pressure and grouting volume ratio parameters meet the standards after grouting, the grouting is completed. If the parameters do not meet the standards, grouting is performed again and the grouting effect is determined until the grouting result parameters meet the standards.

[0006] Preferably, the configuration materials of the ultrafine cement water glass double liquid slurry are small-particle silicate cement, sodium silicate solution, water, and hydroxyethyl methyl fiber, and the weight ratio of silicate cement, sodium silicate solution, water, and hydroxyethyl methyl fiber is 1:1.5:1.2:0.01; step S2 also includes slurry adjustment, and the ultrafine cement water glass double liquid slurry adds additives according to the results of geological exploration to adjust the setting time and volatility of the slurry. When it is necessary to extend the setting time of the slurry, tartaric acid retarder is added, and the configuration ratio of tartaric acid to the ultrafine cement water glass double liquid slurry is 0.05~0.1:1; when it is necessary to enhance the volatility strength, calcium chloride is added, and the configuration ratio of calcium chloride to the ultrafine cement water glass double liquid slurry is 0.02~0.06:1.

[0007] In the grouting condition analysis, grouting control includes pressure control and rate control; Pressure control is to monitor and control the grouting pressure in real time. Multiple distributed pressure monitoring sensors are installed at different positions of the shield machine to monitor the grouting pressure of the upper and lower layers of the tunnel in real time. According to the characteristics of the upper soft and lower hard strata, the grouting pressure is controlled in layers. The grouting pressure of the grouting pump in the upper soft soil part is controlled at 0.1-0.2MPa to avoid excessive squeezing of the soft soil by the slurry and causing soil splitting. The grouting pressure of the grouting pump in the lower hard rock part is set to 0.3-0.5MPa to ensure that the slurry can be effectively injected into the cracks of the rock. The rate control adopts the multi-tube grouting method, using multiple distributed grouting pumps to grout simultaneously and monitor it through flow sensors.

[0008] During the grouting condition analysis, the shield tunnel is monitored and warned, the groundwater level is monitored in real time, and the surface settlement of the strata around the shield machine is monitored using pressure sensors. When the monitoring data reaches the warning value, the warning program is immediately started, the grouting work of the grouting pump is stopped, and emergency rescue construction is carried out.

[0009] During the debugging of the grouting equipment, the orifice pipe of the grouting pipe adopts a hot-rolled seamless steel pipe with a diameter of 50mm and a wall thickness of 3.5mm. The steel pipe is 1m long and a slurry stop valve is installed on the pipe mouth. Hemp thread is wrapped around the pipe wall 30cm after the tail of the pipe to form a cone shape. Anchoring agent is applied on the hemp thread. After the orifice pipe is pushed into the grouting hole, it is firmly buried and the gap between the orifice pipe and the sprayed concrete is sealed with anchoring agent to prevent leakage during the grouting process. The circumferential spacing of the boreholes is 2000-3000mm. According to the soil conditions and reinforcement needs, a second row of annular holes is constructed, and the distance between the second row of boreholes and the first row of boreholes is 3000-4000mm.

[0010] In the process of judging the grouting effect, the dual index control standard of grouting pressure and grouting volume is adopted, that is, when the grouting pressure reaches the set value and the grouting volume reaches more than 85% of the design value, it is considered that the quality requirements have been met.

[0011] In the step of judging the grouting effect, ultrasonic detection is used to detect the synchronous grouting effect. The test instrument adopts SYC-2 acoustic rock parameter measuring instrument. The change law of rock sound velocity is analyzed. The larger the sound velocity amplitude value after grouting, the denser the cracks are filled, and the better the grouting quality and effect.

[0012] The present invention provides a coordinated grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata. It has the following beneficial effects: The present invention provides a coordinated grouting treatment method for a large-diameter shield tunnel with soft upper and hard lower strata, which adopts a specially configured ultrafine cement-water glass double-liquid slurry. The double-liquid slurry has the characteristics of fine particles and can better fill tiny pores. It has the advantage of being more solid in rock and soil reinforcement or anti-seepage engineering for treating tiny cracks. At the same time, the configured slurry has better adhesion and durability. The ultrafine cement-water glass double-liquid slurry configured in the present invention can change the solidification time and volatility strength of the grouting liquid through additives, so that it is suitable for various complex geological conditions and engineering requirements of shield tunnels, and the gel time is adjusted according to the specific situation to achieve the best grouting effect.

[0013] The present invention provides a coordinated grouting treatment method for a large-diameter shield tunnel in an upper soft and lower hard stratum. Through the cooperation of synchronous grouting and secondary grouting, the deformation of the stratum can be effectively controlled at different stages. The synchronous grouting can timely fill the gap between the pipe segment and the stratum during the shield tunneling process, and provide preliminary support for the stratum, thereby achieving the advantage of effectively controlling the terrain. At the same time, a multi-tube grouting method is adopted, and multiple grouting pumps are used for synchronous grouting, which can not only improve the grouting efficiency, but also more precisely control the grouting efficiency, and facilitate the layered control of the grouting pressure, so as to avoid excessive squeezing of the slurry on the soft soil to cause soil splitting, and also ensure that the slurry can be effectively injected into the cracks of the rock. It is more suitable for grouting operations in a layered sandy soil environment with an upper soft soil and a lower hard soil. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of the collaborative grouting treatment method of the present invention; Figure 2 It is a workflow diagram for analyzing grouting conditions of the grouting treatment method of the present invention; Figure 3 It is a schematic diagram of grouting drilling of the coordinated grouting treatment method of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In the description of this application, it should be noted that the terms used here are only for describing specific implementations, and are not intended to limit the exemplary implementations according to the present application. For ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and devices known to ordinary technicians in the relevant fields may not be discussed in detail, but where appropriate, the techniques, methods and devices should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings. Example

[0016] like Figure 1-Figure 3 As shown, an embodiment of the present invention provides a coordinated grouting treatment method for a large-diameter shield tunnel in an upper soft and lower hard stratum, and the coordinated grouting treatment method for a large-diameter shield tunnel in an upper soft and lower hard stratum includes the following steps: S1: Investigate the geology of the grouting site and prepare for grouting construction; S2: Grouting parameter management, including slurry modulation, and the ultrafine cement water glass double liquid slurry is modulated according to the upper soft and lower hard strata; the configuration materials of the ultrafine cement water glass double liquid slurry are small-particle (0.1-2μm) silicate cement, sodium silicate solution, water, and hydroxyethyl methyl fiber, and the weight configuration ratio of silicate cement, sodium silicate solution, water, and hydroxyethyl methyl fiber is 1:1.5:1.2:0.01; the ultrafine cement water glass double liquid slurry can add additives according to the results of geological exploration to adjust the setting time and volatility of the slurry. When it is necessary to extend the setting time of the slurry, tartaric acid retarder is added, and the configuration ratio of tartaric acid to ultrafine cement water glass double liquid slurry is 0.05~0.1:1. When it is necessary to enhance the volatility strength, calcium chloride is added, and the configuration ratio of calcium chloride to ultrafine cement water glass double liquid slurry is 0.02~0.06:1; S3: Debugging of grouting equipment, and evenly burying grouting conduits in the through holes of large-diameter shield tunnels; S4: Grouting: multiple grouting holes pre-set at the shield tail are grouting synchronously under pressure, and a pressure divider is set at the outlet of each grouting hole to control the grouting pressure between 0.1-0.5MPa; S5: Grouting condition analysis: timely monitoring and early warning as well as grouting control are carried out according to the deformation monitoring results of the segment lining in the tunnel and the deformation of the ground and surrounding buildings, and timely solutions are provided when any problems are found; S6: Secondary grouting: according to the analysis of grouting conditions, the grouting parameters are adjusted. If the synchronous grouting is found to be insufficient, secondary grouting is carried out through the grouting holes in the middle of the segment to fill the unfilled part and the reduced volume part of the primary grouting. S7: Determination of grouting effect. After the grouting stops, the grouting effect in the tunnel is monitored, analyzed and evaluated to determine whether it meets the standards. If the tunnel pressure and grouting volume ratio parameters meet the standards after grouting, the grouting is completed. If the parameters do not meet the standards, grouting is performed again and the grouting effect is determined until the grouting result parameters meet the standards.

[0017] In the grouting condition analysis, grouting control includes pressure control and rate control; Pressure control is to monitor and control the grouting pressure in real time. Multiple distributed pressure monitoring sensors are installed at different positions of the shield machine to monitor the grouting pressure of the upper and lower layers of the tunnel in real time. According to the characteristics of the upper soft and lower hard strata, the grouting pressure is controlled in layers. The grouting pressure of the grouting pump in the upper soft soil part is controlled at 0.1-0.2MPa to avoid excessive squeezing of the soft soil by the slurry and causing soil splitting. The grouting pressure of the grouting pump in the lower hard rock part is set to 0.3-0.5MPa to ensure that the slurry can be effectively injected into the cracks of the rock. The rate control adopts the multi-tube grouting method, using multiple distributed grouting pumps to grout simultaneously and monitor it through flow sensors.

[0018] During the grouting condition analysis, the shield tunnel is monitored and warned, the groundwater level is monitored in real time, and the surface settlement of the strata around the shield machine is monitored using pressure sensors. When the monitoring data reaches the warning value, the warning program is immediately started, the grouting work of the grouting pump is stopped, and emergency rescue construction is carried out.

[0019] During the commissioning of the grouting equipment, the orifice pipe of the grouting pipe adopts a hot-rolled seamless steel pipe with a diameter of 50mm and a wall thickness of 3.5mm. The steel pipe is 1m long, and a slurry stop valve is set on the pipe mouth. Hemp is wound on the pipe wall 30cm after the tail of the pipe to form a spindle shape. Anchoring agent is applied on the hemp. After the orifice pipe is pushed into the grouting hole, it is firmly buried and the gap between the orifice pipe and the sprayed concrete is sealed with anchoring agent to prevent leakage during the grouting process. The circumferential spacing of the boreholes is 2000-3000mm. In addition, a second row of annular holes can be constructed according to the soil conditions and reinforcement needs. The distance between the second row of boreholes and the first row of boreholes is 3000-4000mm. In the grouting pressure control, it is necessary to first calculate the ideal grouting pressure through theoretical analysis, the lower critical grouting pressure The soil block must be kept stable and not collapse, while the critical grouting pressure The soil block must be kept stable and not bulging, and the ideal grouting pressure It falls within this range. According to static analysis: ;

[0020] ;

[0021] ; ; in, : upper critical grouting pressure; : lower critical grouting pressure; : Ideal grouting pressure; : Unit weight, unit weight of soil within the grouting range, unit is kN / m 3 ; : Unconsolidated undrained shear strength, in kPa or kN / m 2 ; : Characteristic size, the width of the soil within the grouting range, foundation diameter or other relevant dimensions, in meters; : Action height, the depth of the soil within the grouting range, in m; : internal friction angle, shear strength characteristic of soil, unit is degree or radian; : The length from the slurry pressure inlet to the pressure outlet; : Total height of soil, in m; : A dimensionless coefficient representing the number of distributed soil layers.

[0022] In the initial stage of grouting, in order to ensure that the building gap behind the pipe segment is fully filled, grouting is performed at a higher pressure as much as possible. Generally, a slightly higher grouting pressure is set and the injection volume is managed at the same time. During the grouting process, in the construction of large-diameter shield tunnels in soft and hard strata, Figure 3 Shown, Figure 3 In the process, excavate the contour line 1, design the grouting reinforcement edge line 2, and the grouting hole 3; the grouting equipment should accurately control the grouting amount according to the advancing speed of the shield machine and the porosity of the stratum, and the grouting time should be controlled within 12 to 30 hours. For soft soil layers, excessive grouting pressure should be avoided to cause stratum uplift. The grouting pipe is usually arranged at the tail of the shield machine, and the slurry is evenly injected into the gap between the pipe segment and the stratum through the grouting pipe. The grouting time is controlled within 5 to 7 hours.

[0023] Grouting, inspection, recording and analysis shall be carried out strictly according to the requirements. In the process of judging the grouting effect, the dual index control standard of grouting pressure and grouting volume shall be adopted, that is, when the grouting pressure reaches the set value and the grouting volume reaches more than 85% of the design value, the quality requirements are considered to have been met.

[0024] In the monitoring, analysis and evaluation steps, ultrasonic waves are used to detect the effect of synchronous grouting. The test instrument uses the SYC-2 acoustic rock parameter measuring instrument. The analysis is carried out through the change law of rock mass sound velocity and the hole grouting pressure, injection volume and other conditions. The larger the sound velocity amplitude value after grouting, the denser the cracks are filled. The better the grouting quality and effect, thus achieving the purpose of filling gaps and consolidating water.

[0025] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A collaborative grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata, characterized in that: The following steps are involved: S1: Investigate the geology of the grouting site and prepare for grouting construction; S2: Grouting parameter management, including slurry modulation, and modulation of ultra-fine cement-water glass double liquid slurry according to the upper soft and lower hard strata; S3: Debugging of grouting equipment, and evenly burying grouting conduits in the through holes of large-diameter shield tunnels; S4: Grouting: multiple grouting holes pre-set at the shield tail are grouting synchronously under pressure, and a pressure divider is set at the outlet of each grouting hole to control the grouting pressure between 0.1-0.5MPa; S5: Grouting condition analysis: timely monitoring and early warning as well as grouting control are carried out according to the deformation monitoring results of the segment lining in the tunnel and the deformation of the ground and surrounding buildings, and timely solutions are provided when any problems are found; S6: Secondary grouting: according to the analysis of grouting conditions, the grouting parameters are adjusted. If the synchronous grouting is found to be insufficient, secondary grouting is carried out through the grouting holes in the middle of the segment to fill the unfilled part and the reduced volume part of the primary grouting. S7: Determination of grouting effect. After the grouting stops, the grouting effect in the tunnel is monitored, analyzed and evaluated to determine whether it meets the standards. If the tunnel pressure and grouting volume ratio parameters meet the standards after grouting, the grouting is completed. If the parameters do not meet the standards, grouting is performed again and the grouting effect is determined until the grouting result parameters meet the standards.

2. The coordinated grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata according to claim 1 is characterized in that: The configuration materials of the ultrafine cement water glass double liquid slurry are small-particle silicate cement, sodium silicate solution, water, and hydroxyethyl methyl fiber, and the weight configuration ratio of silicate cement, sodium silicate solution, water, and hydroxyethyl methyl fiber is 1:1.5:1.2:0.01; step S2 also includes slurry adjustment, and the ultrafine cement water glass double liquid slurry adds additives according to the results of geological exploration to adjust the setting time and volatility strength of the slurry. When it is necessary to extend the setting time of the slurry, a tartaric acid retarder is added, and the configuration ratio of tartaric acid to the ultrafine cement water glass double liquid slurry is 0.05-0.1:1; When it is necessary to enhance the volatility, calcium chloride is added. The configuration ratio of calcium chloride to ultrafine cement water glass double liquid slurry is 0.02~0.06:

1.

3. The coordinated grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata according to claim 1 is characterized by: In the grouting condition analysis, grouting control includes pressure control and rate control; Pressure control is to monitor and control the grouting pressure in real time. Multiple distributed pressure monitoring sensors are installed at different positions of the shield machine to monitor the grouting pressure of the upper and lower layers of the tunnel in real time. According to the characteristics of the upper soft and lower hard strata, the grouting pressure is controlled in layers. The grouting pressure of the grouting pump in the upper soft soil part is controlled at 0.1-0.2MPa to avoid excessive squeezing of the soft soil by the slurry and causing soil splitting. The grouting pressure of the grouting pump in the lower hard rock part is set to 0.3-0.5MPa to ensure that the slurry can be effectively injected into the cracks of the rock. The rate control adopts the multi-tube grouting method, using multiple distributed grouting pumps to grout simultaneously and monitor it through flow sensors.

4. The coordinated grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata according to claim 1 is characterized in that: During the grouting condition analysis, the shield tunnel is monitored and warned, the groundwater level is monitored in real time, and the surface settlement of the strata around the shield machine is monitored using pressure sensors. When the monitoring data reaches the warning value, the warning program is immediately started, the grouting work of the grouting pump is stopped, and emergency rescue construction is carried out.

5. The coordinated grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata according to claim 1 is characterized in that: During the debugging of the grouting equipment, the orifice pipe of the grouting pipe adopts a hot-rolled seamless steel pipe with a diameter of 50mm and a wall thickness of 3.5mm. The steel pipe is 1m long and a slurry stop valve is installed on the pipe mouth. Hemp thread is wrapped around the pipe wall 30cm after the tail of the pipe to form a cone shape. Anchoring agent is applied on the hemp thread. After the orifice pipe is pushed into the grouting hole, it is firmly buried and the gap between the orifice pipe and the sprayed concrete is sealed with anchoring agent to prevent leakage during the grouting process. The circumferential spacing of the boreholes is 2000-3000mm. According to the soil conditions and reinforcement needs, a second row of annular holes is constructed, and the distance between the second row of boreholes and the first row of boreholes is 3000-4000mm.

6. The coordinated grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata according to claim 1 is characterized by: In the process of judging the grouting effect, the dual index control standard of grouting pressure and grouting volume is adopted, that is, when the grouting pressure reaches the set value and the grouting volume reaches more than 85% of the design value, it is considered that the quality requirements have been met.

7. The coordinated grouting treatment method for a large-diameter shield tunnel in soft upper and hard lower strata according to claim 1 is characterized by: In the step of judging the grouting effect, ultrasonic detection is used to detect the synchronous grouting effect. The test instrument adopts SYC-2 acoustic rock parameter measuring instrument. The change law of rock sound velocity is analyzed. The larger the sound velocity amplitude value after grouting, the denser the cracks are filled, and the better the grouting quality and effect.

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