Tunnel shield tunneling construction method

Abstract

The invention discloses a tunnel shield tunneling construction method, which relates to the technical field of tunnel construction, and comprises the following steps: S1, arranging a plurality of vacuumizing floral tubes on a tunnel face towards a rock-soil body to be excavated, and connecting the vacuumizing floral tubes with a vacuum pump to form a negative pressure vacuumizing system; s2, spraying a rapid-hardening sealing cementing material on the tunnel face; s3, the rock-soil body to be excavated is subjected to vacuumizing consolidation and reinforcement; s4, the edge of the tunnel excavation section is excavated, and a groove is formed; s5, steel supports are arranged in the annular arch groove, micro piles are arranged at the arch springing positions and used for supporting the steel supports, fiber concrete is sprayed, and a primary lining supporting system is formed; and S6, after the supporting system is completed, the remaining core soil body of the tunnel face is excavated, a waterproof coating film is sprayed on the surface of the primary lining, secondary lining supporting is constructed, and the next cycle is prepared. The soil arch effect of the surrounding rock-soil body is fully utilized, the steel support and the sprayed concrete system form a shield shell, the stability of the surrounding rock-soil body of the tunnel is improved, and the mechanical construction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, and in particular to a tunnel shield excavation construction method. Background Art

[0002] Tunnels allow vehicles to directly cross mountains or rivers, avoiding the time and distance wasted by detours. As road and rail networks and urban subway construction planning are increasingly improved, dark-cut tunnels are being built in large numbers. In the construction of dark-cut tunnels, the main construction methods currently used include shield tunneling, TBM, drilling and blasting, etc.

[0003] Both the shield method and the TBM method are circular full-section excavation methods, and their adaptability to the working environment is different. The TBM is a hard rock tunnel boring machine, and the shield is a soft soil tunnel boring machine. When the properties of the surrounding rock change greatly, it will bring great difficulties to the construction. The risks and difficulties in construction of high-altitude stress and large-deformation soft rocks are extremely high. At the same time, tunnel construction often uses horseshoe or rectangular sections, and circular sections often result in large excavation areas and excessive energy consumption.

[0004] The drilling and blasting method is applicable to a wide range of strata, but the construction speed is slow, the construction conditions are poor, and the disturbance to the surrounding environment is large. During construction, the stability of surrounding structures and facilities is often affected. The drilling and blasting method mostly uses grouting, anchor rods, pipe sheds and other technologies for reinforcement. The technical principle is to increase the stability of the surrounding rock and soil by changing external factors, and does not fully utilize the inherent characteristics of the rock and soil such as the soil arch effect. In addition, there are shortcomings such as poor reinforcement effect, long construction period, and poor economy due to the uncontrollable grouting range and quality, the inability of anchor rods and pipe sheds to fully reinforce the surrounding rock and soil, and the overall carbon emissions are high, which does not conform to my country's low-carbon and environmentally friendly development concept.

[0005] Therefore, how to provide a tunnel shield excavation method suitable for a variety of soil layers is an urgent problem to be solved in tunnel construction at this stage.

[0006] The present invention provides a tunnel shield excavation method suitable for any soil layer. This method can resist and overcome the deformation of soft rock and prevent the rock burst of surrounding rock. It is energy-saving, safe and fast. The construction equipment overcomes the limitations of geological conditions. The equipment is small and flexible, the construction speed is fast and the cost is low. Summary of the invention

[0007] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides a tunnel shield excavation construction method to solve at least one technical problem raised in the background technology.

[0008] (II) Technical solution To achieve the above object, the technical solution adopted by the present invention is: a tunnel shield excavation construction method, the steps of the tunnel shield excavation construction method include: Step S1: a plurality of drainage pipes and vacuum pipes are installed on the tunnel face toward the rock and soil to be excavated, and the vacuum pipes are connected to a vacuum pump to form a negative pressure vacuum system; Step S2: spraying quick-setting sealing cementitious material on the tunnel face; Step S3: vacuum consolidation and reinforcement of the rock and soil to be excavated; Step S4: excavating the edge of the tunnel to form an arched groove; Step S5: arranging steel supports in the arched groove, and driving micro piles at the arch foot to support the steel supports, so as to form a support system; Step S6: After the support system is completed, the remaining soil is excavated, permanent support is applied, and preparation for the next cycle is made.

[0009] Preferably, the drainage pipe is located at the lower part of the tunnel face.

[0010] Preferably, the vacuum flower pipe includes a horizontal vacuum tube and an oblique vacuum tube, wherein the horizontal vacuum tube is arranged in the middle of the tunnel face, and the oblique vacuum tube is arranged at the edge of the tunnel face.

[0011] Preferably, the horizontal vacuum tubes are arranged in a plum blossom or square form on the face, the diameter of the horizontal vacuum tubes is 2 to 10 cm, the tube spacing of the horizontal vacuum tubes is 0.5 to 2.0 m, and the driving depth is 3 to 5 times the single excavation length.

[0012] Preferably, the inclined vacuum tube is inclined so as to spread outward from the tunnel, and the angle of the inclined installation is 5 to 30°.

[0013] Preferably, the quick-setting sealing cementitious material sprayed in step S2 is a base material formed by mixing and stirring components of 30% to 50% cement, 40% to 50% medium-coarse sand, 3% to 8% calcium aluminate, 1% to 2% sodium carbonate and 0.2% to 1% sodium chlorate. During construction, any one or more of chloroform emulsion, acrylic emulsion and polyurethane emulsion are mixed, and the base material and the same weight of emulsion are added with appropriate amount of water, mixed and stirred, and then sprayed on the face of the palm.

[0014] Preferably, in the step S3, the vacuum degree of the vacuum is -20 to -80 kPa during the vacuum consolidation reinforcement of the rock and soil to be excavated, and the vacuum duration can be 2 to 24 hours.

[0015] Preferably, the width of the arched trench formed by excavation in step S4 is 1 to 2 m, and the depth is the length of a single excavation.

[0016] Preferably, in step S5, the steel support is an I-beam or an H-beam, the shape of which is consistent with the inner contour of the tunnel, and the micro-piles at the arch foot position are cast in situ and then inserted into prefabricated piles to form tough core piles.

[0017] Preferably, in step S6, a waterproof coating is sprayed on the surface of the primary lining, wherein the sprayed waterproof coating is a modified coating formed by mixing any one or more of chloroform emulsion, acrylic emulsion, and polyurethane emulsion and then adding 1% to 10% of KH560 silane coupling agent.

[0018] (III) Beneficial effects The present invention provides a tunnel shield excavation construction method, which has the following beneficial effects compared with the prior art: It makes full use of the soil arch effect of the surrounding rock and soil, and uses the soil arch effect and the steel support system to form a shield, thereby greatly improving the stability of the tunnel surrounding rock and soil, allowing full-section excavation with low comprehensive energy consumption and safety and reliability.

[0019] The pore pressure in the water-rich soft layer can be reduced by drain pipes and vacuum flower pipes. According to the effective stress principle and shear strength theory, the effective stress of the soil will increase, and the effective shear strength, an important indicator for controlling the surrounding rock soil, will increase accordingly, making full use of the mechanical properties of the surrounding rock soil itself. In addition, since the vacuum has a large transmission range inside the soil, the above-mentioned reinforcement effect acts on the entire surrounding rock soil, while traditional grouting, pipe sheds, anchor rods and other technologies can only reinforce part of the soil, so this technology has a better reinforcement effect.

[0020] Compared with the grouting method, the embodiment of the present invention does not require large-volume grouting, and high-carbon-emission cement-based gelling materials are less used; compared with pipe roofs and anchor reinforcement, the embodiment of the present invention reduces the use of steel, and both drainage pipes and vacuum pipes can be reused, which has significant low-carbon and environmental protection properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 Provide elevation views for horizontal and diagonal vacuum pipes and drain pipes; Figure 2 This is the front view of the excavated arched trough; Figure 3 This is the front view of the steel support and micro piles; Figure 4 Front view of full section excavation; Figure 5 Side view of horizontal and oblique vacuum pipe and drain pipe layout; Figure 6 This is the side view of the steel support and micro piles; Figure 7 Side view of full-section excavation; Figure 8 The overall schematic diagram of the shield excavation construction of the tunnel; Among them, 1 is an inclined vacuum tube; 2 is a horizontal vacuum tube; 3 is a drainage pipe; 4 is an arched trough; 5 is a steel support; 6 is a micro tough core pile; and 7 is a permanent tunnel support. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of 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.

[0023] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods: As the instruction manual Figure 1-Figure 8 As shown, an embodiment of the present invention provides a tunnel shield excavation construction method, and the steps of the tunnel shield excavation construction method include: Step S1: In the tunnel face of soft soil, soft rock and other strata, multiple drainage pipes 3 and vacuum pipes are set in the rock and soil to be excavated, and the vacuum pipes are connected to the vacuum pump to form a negative pressure vacuum system. Specifically, a larger diameter drainage hole is set at the lower part of the face, and the drainage pipe 3 is placed in the drainage hole, which is convenient for effectively reducing the pore pressure in the water-rich stratum, increasing the effective stress of the soil, and thus improving the strength of the soil; the vacuum pipe is divided into an oblique vacuum pipe 1 and a horizontal vacuum pipe 2, wherein the horizontal vacuum pipe 2 is arranged in the middle of the face, and the oblique vacuum pipe 1 is arranged at the edge of the face, which can reinforce a part of the rock and soil outside the tunnel contour; the side wall of the vacuum pipe is opened to apply vacuum to the surrounding rock and soil. The horizontal vacuum pipe 2 can be arranged in a plum blossom shape, a square shape, etc. on the face, the diameter of the vacuum pipe can be 2 to 10 cm, the pipe spacing is 0.5 to 2.0 m, and the depth of each setting is 3 to 5 times the single excavation length. The inclined vacuum tube 1 is inclined to spread outward from the tunnel, and the angle of the inclined setting is 5 to 30 degrees. Other parameters can be the same as those of the horizontal vacuum tube 2. The inclined vacuum tube 1 and the horizontal vacuum tube 2 can be in two forms: the front is sealed and the rear is perforated, or all perforated.

[0024] Step S2: spray quick-setting sealing cementitious material on the face of the tunnel to make the soil to be excavated in a closed state. The base material of the cementitious material is composed of 30% to 50% cement, 40% to 50% medium-coarse sand, 3% to 8% calcium aluminate, 1% to 2% sodium carbonate and 0.2% to 1% sodium chlorate, which are mixed and stirred for 5 to 10 minutes to form a base material. During construction, any one or more of chlorine-based emulsion, acrylic emulsion and polyurethane emulsion are mixed, and the base material and the emulsion of the same weight are added with appropriate amount of water, mixed and stirred for 3 to 5 minutes, and sprayed on the face of the tunnel. The functions of quick setting, water stopping and airtightness in a humid or water-filled state are realized. After the cementitious material hardens, it is necessary to ensure that the soil to be excavated is in an airtight state.

[0025] Furthermore, quick-setting sealing cementitious material is sprayed on the face to seal the soil to be excavated. After sealing, a pre-vacuum test is carried out to detect the sealing performance. If the sealing performance is not good, the sealing material is sprayed repeatedly.

[0026] Step S3: Vacuum and consolidate the rock and soil to be excavated, so that the effective stress and strength of the rock and soil to be excavated are increased to the excavation limit. The vacuum degree during the vacuuming process can be -20 to -80 kPa, and the vacuuming time can be 2 to 24 hours, which needs to be determined according to the engineering characteristics of the rock and soil. Specifically, the next step is performed after the effective stress and strength of the rock and soil to be excavated are increased to the excavation limit.

[0027] Step S4: excavate the edge of the tunnel to form an annular arch groove 4. The width of the arch groove is 1-2m, and the depth is a single excavation distance, which can be 0.5-4m. Specifically, during the implementation process, shield excavation construction equipment can be selected to excavate the annular edge of the tunnel to form an arch groove 4.

[0028] Step S5: Arrange steel supports 5 in the arched trench 4 to support the surrounding rock. Micro-tough core piles 6 are required to be driven at the soft rock or soft soil arch foot to support the steel supports 5, and 10-20 cm thick fiber concrete is sprayed to form a primary lining support system with the steel supports. The micro-tough core piles 6 have a pile diameter of 300-400 mm and a pile length of 3-4 m. C20-C40 plain concrete is poured, and then prefabricated pipe piles (pile diameter 250-350 mm) are pressed in.

[0029] Step S6: After the shield shell support is completed, the remaining soil can be excavated, and a modified moisture-resistant waterproof coating formed by mixing any one or more of chloroprene emulsion, acrylic emulsion, and polyurethane emulsion and adding 1% to 10% of KH560 silane coupling agent is sprayed on the surface of the support shell as a waterproof layer for the tunnel permanent support 7. Prepare for the next cycle. A specific cycle is to repeat steps S1 to S5 until the tunnel excavation is completed.

[0030] A tunneling method that utilizes or creates the arch effect of the surrounding rock, excavates and supports in an orderly manner to achieve the effect of shield shell stabilization through continuous excavation and rapid construction. It fully utilizes the arch effect of the surrounding rock mass itself or creates the arch effect, and at the same time forms a shield shell stabilization structure with the superimposed support system, thereby greatly improving the stability of the tunnel surrounding rock soil and allowing rapid excavation of the entire section. It is a tunneling technology with low comprehensive energy consumption, high safety and reliability, and suitable for various geological conditions.

[0031] The tunnel shield excavation construction method provided in the above embodiment makes full use of the soil arch effect of the surrounding rock and soil, and uses the soil arch effect and the support structure to form a superimposed shield, which has the advantages of greatly improving the stability of the tunnel surrounding rock and soil, full-section excavation, low comprehensive energy consumption, safety and reliability, etc.

[0032] Furthermore, in soft rock or soft soil surrounding rock, the pore pressure in the water-rich weak layer can be reduced through the drainage pipe 3 and the vacuum flower pipe. According to the effective stress principle and the shear strength theory, the effective stress of the soil will increase, and the effective shear strength, an important indicator for controlling the surrounding rock soil, will increase accordingly, making full use of the mechanical properties of the surrounding rock soil itself; in addition, since the transmission range of the vacuum inside the soil is large, the above-mentioned reinforcement effect acts on the entire surrounding rock soil, while traditional grouting, pipe sheds, anchor rods and other technologies can only reinforce part of the soil, so the reinforcement effect of this technology is better.

[0033] After the surrounding rock mass of soft rock or soft soil is strengthened, a soil arch effect can be formed above and in front of the tunnel face. The upper soil arch can reduce the pressure acting on the tunnel and significantly reduce the tunnel settlement; while the front soil arch can reduce the pressure acting on the tunnel face and significantly reduce the horizontal soil pressure. As a result, the surrounding rock and soil are subjected to less external force, which is more conducive to its stability and the deformation of the tunnel is controllable and small.

[0034] The excavated arch groove reduces the excavation amount when there is no support, speeds up the construction speed, and provides construction space for the steel support 5 and the micro-tough core pile 6. The micro-tough core pile 6 is arranged at the arch foot of the steel support 5, which can effectively reduce the uneven settlement and stability of the support system.

[0035] The soil arch effect and the support system (formed by the steel support 5 and the micro-tough core piles 6) form a shield, which jointly increases the stability of the surrounding rock and soil, thereby reducing the construction cost.

[0036] The face of the tunnel is sealed by spraying sealing cementitious waterproof material, so that the soil to be excavated on the front side of the face of the tunnel is in a closed state, thus ensuring the vacuum effect.

[0037] Due to the existence of soil arch effect, the horizontal soil pressure on the tunnel face is relatively small, so full-section excavation can be adopted, which increases construction efficiency.

[0038] Compared with the grouting method, the embodiment of the present invention does not require large-volume grouting, and high-carbon-emission cement-based gelling materials are less used; compared with pipe roofs and anchor reinforcement, the embodiment of the present invention reduces the use of steel, and both drainage pipes and vacuum pipes can be reused, which has significant low-carbon and environmental protection properties.

[0039] It should be noted that, in this article, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tunnel shield excavation construction method, characterized in that: The steps of the tunnel shield excavation construction method include: Step S1: a plurality of drainage pipes (3) and vacuum pipes are installed on the tunnel face in the rock and soil to be excavated, and the vacuum pipes are connected to a vacuum pump to form a negative pressure vacuum system; Step S2: spraying quick-setting sealing cementitious material on the tunnel face; Step S3: vacuum consolidation and reinforcement of the rock and soil to be excavated; Step S4: excavating the edge of the tunnel excavation section to form an arched groove (4); Step S5: arranging a steel support (5) in the arch groove (4), and driving a micro tough core pile (6) at the arch foot position to support the steel support (5), and spraying fiber concrete with a thickness of 10 to 20 cm to form a primary lining support system with the steel support; Step S6: After the primary lining support system is completed, the remaining core soil of the tunnel face is excavated, and a waterproof coating is sprayed on the surface of the primary lining to apply permanent support (7) and prepare for the next cycle.

2. The tunnel shield excavation construction method according to claim 1, characterized in that: The drainage pipe (3) is located at the lower part of the tunnel face.

3. The tunnel shield excavation construction method according to claim 1 is characterized in that: The vacuum flower pipe comprises a horizontal vacuum tube (2) and an oblique vacuum tube (1), wherein the horizontal vacuum tube (2) is arranged in the middle of the tunnel face, and the oblique vacuum tube (1) is arranged at the edge of the tunnel face.

4. The tunnel shield excavation construction method according to claim 3 is characterized in that: The horizontal vacuum tubes (2) are arranged in a plum blossom or square shape on the face of the tunnel. The diameter of the horizontal vacuum tubes (2) is 2 to 10 cm, the distance between the horizontal vacuum tubes (2) is 0.5 to 2.0 m, and the driving depth is 3 to 5 times the length of a single excavation.

5. The tunnel shield excavation construction method according to claim 3 is characterized by: The inclined vacuum tube (1) is inclined in a manner of spreading outward from the tunnel, and the angle of the inclined installation is 5 to 30 degrees.

6. The tunnel shield excavation construction method according to claim 1, characterized in that: The quick-setting sealing cementitious material sprayed in step S2 is a base material formed by mixing and stirring components by weight of 30% to 50% cement, 40% to 50% medium-coarse sand, 3% to 8% calcium aluminate, 1% to 2% sodium carbonate and 0.2% to 1% sodium chlorate. During construction, any one or more of chloroform emulsion, acrylic emulsion and polyurethane emulsion are used. The base material is mixed with the same weight of emulsion with water and stirred, and then sprayed on the face of the palm.

7. The tunnel shield excavation construction method according to claim 1, characterized in that: In the step S3, during the vacuum consolidation and reinforcement process of the excavated rock and soil body, the vacuum degree of the vacuum is -20 to -80 kPa, and the vacuum time can be 2 to 24 hours.

8. The tunnel shield excavation construction method according to claim 1, characterized in that: The arched trench (4) formed by excavation in step S4 has a width of 1 to 2 m and a depth equal to the length of a single excavation.

9. The tunnel shield excavation construction method according to claim 1, characterized in that: In step S5, the steel support (5) is an I-beam or an H-beam, and its shape is consistent with the inner contour of the tunnel. The micro tough core pile (6) at the arch foot position is a prefabricated pile or a cast-in-place pile.

10. The tunnel shield excavation construction method according to claim 1, characterized in that: The step S6 is to spray a waterproof coating on the primary lining surface, wherein the sprayed waterproof coating is a modified coating formed by adding 1% to 10% of KH560 silane coupling agent to any one or more of chloroformic emulsion, acrylic emulsion, and polyurethane emulsion.

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