Shield tunneling machine anti-drag slurry for stacked tunnel construction and use method of shield tunneling machine anti-drag slurry

Abstract

The invention belongs to the technical field of tunnel engineering, and particularly relates to shield tunneling machine anti-drag slurry for stacked tunnel construction and a use method of the shield tunneling machine anti-drag slurry. According to the anti-drag slurry, bentonite, anhydrous Na2CO3 and water are used as main raw materials, a certain amount of a lubricant and a nanometer material are added into the slurry to prepare the anti-drag slurry, the stress condition between a shield tunneling machine shell and a soil body is monitored in real time, the grouting amount and the grouting pressure of the anti-drag slurry are dynamically adjusted according to the change of soil pressure, and therefore the anti-drag effect of the shield tunneling machine is achieved. The friction force between the shield tunneling machine shell and the surrounding soil body can be reduced, disturbance of the shield tunneling machine shell to the soil body is reduced, consolidation settlement of the soil body in the later period is reduced, and materials and methods are provided for stacked tunnel construction.

Description

Technical Field

[0001] The invention belongs to the technical field of tunnel engineering, and in particular relates to a shield machine drag-reducing slurry used for stacked tunnel construction and a use method thereof. Background Art

[0002] During the tunneling process of the shield machine, there is a small gap between the surrounding rock and the shield. When the convergence deformation of the surrounding rock is too large, it will squeeze the shield and generate friction. When the friction is greater than the maximum thrust of the TBM, it will cause the risk of machine jam. For deep high-stress rock masses, the time-dependent deformation of the surrounding rock is obvious, and machine jam accidents occur frequently.

[0003] The patent application with application number: 202310188249.9 discloses a long-distance pipe jacking drag reduction mud and its preparation method and application. The drag reduction mud is composed of the following components by weight percentage: 4%-8% bentonite, 0.1%-0.5% stabilizer, 0.05%-0.3% sodium polyacrylate, and the balance is water. The drag reduction mud of the present invention is prepared by reasonably preparing the amount of bentonite, stabilizer, sodium polyacrylate and water, so that the obtained drag reduction mud has high viscosity, good fluidity and dispersibility, and small water loss, and excellent comprehensive performance.

[0004] The patent application with application number: 202410968658.5 discloses a mud-water balance caisson jacking construction method, which relates to the field of caisson construction technology, and its steps are as follows: S1: installing tunneling equipment; S2: tunneling machine jacking; S3: jacking pipe entering the soil layer; S4: grouting reinforcement; In the jacking construction, the role of bentonite is to use drag-reducing mud, which is the main measure to reduce the jacking resistance. During jacking, a certain amount of drag-reducing mud is injected into the outer wall of the pipe through the grouting holes on the pipe section, forming a mud ring around the pipe, reducing the friction between the outer wall of the pipe section and the soil layer, thereby reducing the jacking force during jacking. This method is applicable to a wide range of soil types and can effectively maintain the stability of the excavation surface.

[0005] The patent application with application number: 202310412241.6 discloses an array-type rectangular tunnel structure and a construction method for forming interconnected underground spaces. It relates to the field of underground engineering technology. It includes at least two columns of tunnel groups, each column of tunnel groups includes at least two layers of tunnels, the upper layer in each column of tunnel groups is a rectangular pipe segment A, and the lower layer is a rectangular pipe segment B. A plurality of guide rails are provided on the top of the rectangular pipe segment B, and the guide rails are connected to the embedded parts in the rectangular pipe segment B. The guide rails are used for guiding the jacking of the rectangular pipe segment A during implementation; each section of the tunnel includes a plurality of rectangular pipe segments connected in sequence, and the rectangular pipe segment is a prefabricated reinforced concrete structure. A plurality of grouting holes are reserved on the rectangular pipe segment, and drag-reducing mud or solidified slurry is injected into the outside of the rectangular pipe segment through the grouting holes. The method of the present invention is environmentally friendly and effectively solves the problems of replacing manual labor with machinery and construction safety in terms of construction means.

[0006] In the prior art, during the tunneling process of the shield machine, there is a small gap between the surrounding rock and the shield. When the convergence deformation of the surrounding rock is too large, it will squeeze the shield and generate friction. When the friction is greater than the maximum thrust of the TBM, it will cause the risk of machine jam. For deep high-stress rock masses, the time-dependent deformation of the surrounding rock is obvious, and machine jam accidents occur frequently. Summary of the invention

[0007] Based on the above technical background, the main purpose of the present invention is to provide a shield machine drag reducing mud for stacked tunnel construction and a method of using the same, so as to overcome the shortcomings of the prior art.

[0008] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0009] The first aspect of the present invention is to provide a shield machine drag reduction slurry for stacked tunnel construction, wherein the shield machine drag reduction slurry for stacked tunnel construction comprises the following raw materials in parts by weight:

[0010] 70-90 parts by weight of bentonite;

[0011] Anhydrous Na2CO3 1-5 parts by weight;

[0012] 900-950 parts by weight of water.

[0013] Preferably, the shield machine drag reduction slurry for stacked tunnel construction comprises the following raw materials in parts by weight:

[0014] 80 parts by weight of bentonite;

[0015] Anhydrous Na2CO3 3 parts by weight;

[0016] Water: 920 parts by weight.

[0017] Preferably, the drag-reducing slurry for shield machine used for stacked tunnel construction also includes a lubricant, and the added amount of the lubricant is 0.1-0.3% of the total weight of the drag-reducing slurry for shield machine used for stacked tunnel construction.

[0018] More preferably, the lubricant is selected from one or more of carboxymethyl cellulose and soda ash.

[0019] Preferably, the drag-reducing slurry for shield machine used for stacked tunnel construction further comprises nanomaterials, and the added amount of the nanomaterials is 1 to 3% of the total weight of the drag-reducing slurry for shield machine used for stacked tunnel construction.

[0020] More preferably, the nanomaterial is selected from one or both of nano-silicon dioxide and nano-clay.

[0021] The second aspect of the present invention is to provide a method for using the shield machine drag reduction slurry for stacked tunnel construction according to the first aspect of the present invention, the method comprising the following steps:

[0022] Step 1, weighing bentonite, sodium carbonate and water, mixing, stirring for reaction, and then standing for expansion to obtain drag-reducing mud;

[0023] Step 2: During the advancement of the shield machine, add drag-reducing slurry to the outside of the shield shell. When the segment is separated from the shield tail, perform secondary grouting, and perform grouting again every two rings.

[0024] In step 1,

[0025] Preferably, the weighed bentonite, sodium carbonate and water are mixed, stirred and reacted at room temperature for 0.5 to 1 hour, and after the stirring reaction, allowed to stand and expand for 1 to 3 hours;

[0026] Lubricant and nano-material are added to the statically expanded mud, and the mixture is evenly mixed to obtain drag-reducing mud.

[0027] In step 2,

[0028] Preferably, the amount of grouting each time is 130% to 180% of the theoretical amount of grouting, and the theoretical amount of grouting is calculated according to formula (1):

[0029] V=π× (D1 2 -D2 2 ) / 4×L Formula (1);

[0030] In formula (1), D1 is the outer diameter of the cutterhead; D2 is the outer diameter of the segment; L is the excavation length of each ring.

[0031] Preferably, the pressure of adding drag reducing slurry and grouting is calculated according to formula (2) and formula (3):

[0032]

[0033] σ z =γh=γ1h1+γ2h2+γ3h3 Formula (3).

[0034] In formula (2) and formula (3), γ is soil weight, i.e., the gravity per unit soil mass; h is soil layer thickness; φ is internal friction angle; σ is pressure.

[0035] Beneficial effects of the present invention: lack of the beneficial effects corresponding to right 1

[0036] (1) The present invention uses bentonite, anhydrous Na2CO3 and water as the basic mud, and adds a certain amount of lubricant and nanomaterials to make the drag-reducing mud. The lubricant can improve and enhance the lubricity of the drag-reducing mud and reduce the friction coefficient between the shield casing and the soil; the nanomaterial can fill the tiny pores in the mud, improve the density and viscosity stability of the mud, thereby extending the service life of the lubricating layer and the drag-reducing performance.

[0037] (2) The method for using the drag-reducing mud of the present invention monitors the stress conditions between the shield casing and the soil in real time, and dynamically adjusts the grouting amount and grouting pressure of the mud according to the change of soil pressure. During the shield construction, a thin film is formed between the shield casing and the soil, so that the casing and the soil are always lubricated. This not only ensures the effectiveness of the lubricating layer, but also avoids the waste of mud, and can effectively reduce the friction between the shield casing and the surrounding soil, reduce the disturbance of the shield casing to the soil, and reduce the consolidation settlement of the soil in the later period. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram showing a method for using the shield machine drag-reducing slurry for stacked tunnel construction according to the present invention. DETAILED DESCRIPTION

[0039] The present invention will be described in detail below, and the characteristics and advantages of the present invention will become clearer and more distinct with the description.

[0040] The first aspect of the present invention is to provide a shield machine drag reduction slurry for stacked tunnel construction, wherein the shield machine drag reduction slurry for stacked tunnel construction comprises the following raw materials in parts by weight:

[0041] 70-90 parts by weight of bentonite;

[0042] Anhydrous Na2CO3 1-5 parts by weight;

[0043] 900-950 parts by weight of water.

[0044] Preferably, the shield machine drag reduction slurry for stacked tunnel construction comprises the following raw materials in parts by weight:

[0045] 80 parts by weight of bentonite;

[0046] Anhydrous Na2CO3 3 parts by weight;

[0047] Water: 920 parts by weight.

[0048] The drag-reducing mud for shield machine used for stacked tunnel construction also includes lubricant, and the added amount of the lubricant is 0.1-0.3% of the total weight of the drag-reducing mud for shield machine used for stacked tunnel construction.

[0049] Preferably, the amount of lubricant added is 0.2% of the total weight of the shield machine drag reduction mud used for stacked tunnel construction.

[0050] The lubricant is selected from one or more of carboxymethyl cellulose and soda ash. Preferably, the lubricant is carboxymethyl cellulose.

[0051] By adding lubricants, the lubricity of the drag-reducing slurry can be improved and enhanced, and the friction coefficient between the shield casing and the soil can be reduced.

[0052] The drag-reducing mud for shield machine used for stacked tunnel construction also includes nano materials, and the added amount of the nano materials is 1-3% of the total weight of the drag-reducing mud for shield machine used for stacked tunnel construction.

[0053] Preferably, the added amount of the nano material is 2% of the total weight of the shield machine drag reduction mud used for stacked tunnel construction.

[0054] The nano material is selected from one or both of nano silicon dioxide and nano clay. Preferably, the nano material is nano silicon dioxide.

[0055] The nano material added in the present invention can fill the tiny pores in the mud, improve the compactness and viscosity stability of the mud, thereby extending the service life of the lubricating layer. Adding 2% of nano SiO2 can improve the drag reduction performance of the mud by about 14%.

[0056] The second aspect of the present invention is to provide a method for using the shield machine drag reduction slurry for stacked tunnel construction according to the first aspect of the present invention, such as Figure 1 As shown, the method of use comprises the following steps:

[0057] Step 1, weighing bentonite, sodium carbonate and water, mixing, stirring for reaction, and then standing for expansion to obtain drag-reducing mud;

[0058] Step 2: During the advancement of the shield machine, add drag-reducing slurry to the outside of the shield shell. When the segment is separated from the shield tail, perform secondary grouting, and perform grouting again every two rings.

[0059] The above steps are described in detail below.

[0060] In step 1, the weighed bentonite, sodium carbonate and water are mixed and stirred at room temperature for 0.5 to 1 hour to ensure that the raw materials are fully mixed.

[0061] Preferably, the reaction is stirred at room temperature for 0.5 to 0.8 h.

[0062] After stirring and reacting, the mixture is allowed to stand for 1 to 3 hours, preferably 1 to 2 hours. The mixture is allowed to stand for a period of time to form a drag reduction slurry with good thixotropy. During this process, the slurry undergoes expansion to form a slurry with excellent drag reduction effect.

[0063] Preferably, lubricant and nanomaterial are added to the statically expanded mud and mixed evenly to obtain drag-reducing mud.

[0064] In step 2, during the advancement of the shield machine, in order to ensure the settlement control after the shield construction so that it does not affect the use function, when the segment is separated from the shield tail 6 to 8 rings, secondary grouting should be carried out in time, and grouting should be carried out again every two rings.

[0065] In order to ensure the grouting amount, the grouting material will shrink. Therefore, the grouting must exceed the theoretical gap volume. However, excessive grouting will cause surface uplift or local grouting, which will also affect the stress state of the segment. The grouting amount each time should be 130% to 180% of the theoretical grouting amount. The excavation diameter of the shield cutter head in the project is generally 6.390m, and the outer diameter of the prefabricated reinforced concrete segment is generally 6.2m. Theoretically, for each ring of excavation, the theoretical volume of the gap between the space formed by the shield excavation and the outer wall of the segment (i.e., the theoretical grouting amount) is calculated according to formula (1):

[0066] V=π× (D1 2 -D2 2 ) / 4×L Formula (1);

[0067] In formula (1), D1 is the outer diameter of the cutterhead; D2 is the outer diameter of the segment; L is the excavation length of each ring.

[0068] The pressure of adding drag reduction slurry and grouting is calculated according to formula (2) and formula (3):

[0069]

[0070] σ z =γh=γ1h1+γ2h2+γ3h3 Formula (3).

[0071] In formula (2) and formula (3), γ is soil density, i.e., the gravity per unit soil mass; h is soil layer thickness; φ is internal friction angle; σ is pressure.

[0072] The grouting pressure is usually 0.1-0.45 MPa, and preferably, the grouting pressure is 0.15-0.3 MPa.

[0073] The amount of slurry added each time is usually 500-800L, preferably, the amount of slurry added each time is 600-700L.

[0074] For strata with different geological structures, the viscosity ratio of bentonite mud needs to be adjusted accordingly: for pure soil geological layers: 12% bentonite, 0.6% soda ash, and add an appropriate amount of 1 / 1000 cellulose; for loose geological layers: 12% bentonite, 1.0% soda ash, and add an appropriate amount of 1 / 1000 cellulose; for half sand and half soil layers: 12% bentonite, 1.5% soda ash, add an appropriate amount of 1 / 1000 cellulose and 1 / 1000 sodium salt; for pure sand geological layers: 18% bentonite, 3.0% soda ash, add an appropriate amount of 1 / 1000 cellulose and 1 / 1000 sodium salt; for rocky geological layers: 20% bentonite, 5.0% soda ash, add an appropriate amount of 1 / 1000 cellulose and 1 / 1000 sodium salt.

[0075] Example

[0076] The present invention is further described below by means of specific examples. These embodiments are only intended to illustrate the present invention but are not intended to limit the scope of the present invention.

[0077] Example 1

[0078] Weigh 80 parts by weight of bentonite, 3 parts by weight of anhydrous Na2CO3, and 920 parts by weight of water.

[0079] Mix the weighed bentonite, sodium carbonate and water, and stir to react for 0.5 to 0.8 hours at room temperature. After stirring to react, let it stand for 1 to 2 hours for expansion.

[0080] Add 2% of the total weight of the nano material nano silicon dioxide to the statically expanded mud, then add 0.2% of the total weight of the lubricant carboxymethyl cellulose to the mud, mix well, and obtain the drag reduction mud.

[0081] In order to ensure the settlement control after shield construction and not affect the use function, when the segment is out of the appropriate position of the shield tail (usually 6-8 rings), secondary grouting should be carried out in time, and grouting should be carried out again every two rings. The amount of grouting each time is calculated according to formula (1). The grouting amount is generally 600-700L. The actual grouting amount calculated according to formula (1) is 3-4.2m 3The grouting pressure is calculated according to formula (2) and formula (3). The grouting pressure is generally 0.15-0.3 MPa, and the flow rate and pressure are dual controlled.

[0082] To ensure the amount of grouting, taking the Shenyang urban area tunnel project as an example, the shield machine cutter head excavation diameter is 6.390m, and the outer diameter of the prefabricated reinforced concrete segment is 6.2m. Theoretically, for each ring of excavation, the theoretical volume of the gap between the space formed by the shield excavation and the outer wall of the segment is:

[0083] V=π× (D1 2 -D2 2 ) / 4×L Formula (1);

[0084] In formula (1), D1 is the outer diameter of the cutterhead; D2 is the outer diameter of the segment; L is the excavation length of each ring.

[0085] According to formula (1), the theoretical grouting volume V = 2.3m 3 The actual grouting volume is 130% to 180% of the theoretical building gap, that is, the actual grouting volume is: 3 to 4.2m 3 .

[0086] The grouting pressure should be controlled during the grouting process. Taking the strata of the tunnel in Shenyang as an example, from top to bottom, they are mixed fill soil, silty clay, medium-coarse sand, gravel sand, rounded gravel, gravel sand, and clay-containing rounded gravel layer. The mixed fill soil layer: γ = 19.2 kN / m 3 , φ=8°; fill layer: γ=19.1kN / m3, φ=8°, c=10KP, silty clay layer: γ=19.8kN / m 3 , φ=12°, c=12KPa; gravel layer: γ=20.5kN / m 3 , φ=35°; gravel sand layer: γ=20kN / m 3 , φ=40°, the injection pressure of the mud (the pressure of adding drag-reducing mud and grouting) is generally slightly higher than the soil pressure in the soil bin.

[0087] Calculate the soil bulk density according to γ=20kN / m 3 The soil pressure is calculated using the Rankine theory.

[0088]

[0089] σ z =γh=γ1h1+γ2h2+γ3h3 Formula (3).

[0090] In formula (2) and formula (3), γ: soil weight, that is, the gravity of unit soil; γ1, γ2, γ3 represent the soil weight of each soil layer; h: soil layer thickness; h1, h2, h3 represent the thickness of each soil layer; φ: internal friction angle; C: cohesion, σ a : Grouting pressure, σz : Calculate the intermediate pressure.

[0091] Example 2

[0092] The drag reduction slurry was used in a manner similar to that of Example 1, except that 70 parts by weight of bentonite, 5 parts by weight of anhydrous Na2CO3, and 950 parts by weight of water were weighed.

[0093] Example 3

[0094] The drag reduction slurry was used in a similar manner to Example 1, except that 90 parts by weight of bentonite, 1 part by weight of anhydrous Na2CO3, and 900 parts by weight of water were weighed.

[0095] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A shield machine drag reduction slurry for stacked tunnel construction, characterized in that: The shield machine drag reduction slurry used for stacked tunnel construction includes the following raw materials in parts by weight: 70-90 parts by weight of bentonite; Anhydrous Na2CO3 1-5 parts by weight; 900-950 parts by weight of water.

2. The shield machine drag reduction slurry for stacked tunnel construction according to claim 1 is characterized in that: The shield machine drag reduction slurry used for stacked tunnel construction includes the following raw materials in parts by weight: 80 parts by weight of bentonite; Anhydrous Na2CO3 3 parts by weight; Water: 920 parts by weight.

3. The shield machine drag reduction slurry for stacked tunnel construction according to claim 1, characterized in that: The drag-reducing mud for shield machine used for stacked tunnel construction also includes lubricant, and the added amount of the lubricant is 0.1-0.3% of the total weight of the drag-reducing mud for shield machine used for stacked tunnel construction.

4. The shield machine drag reduction slurry for stacked tunnel construction according to claim 3 is characterized in that: The lubricant is selected from one or more of carboxymethyl cellulose and soda ash.

5. The shield machine drag reduction slurry for stacked tunnel construction according to claim 1, characterized in that: The drag-reducing mud for shield machine used for stacked tunnel construction also includes nano materials, and the added amount of the nano materials is 1-3% of the total weight of the drag-reducing mud for shield machine used for stacked tunnel construction.

6. The shield machine drag reduction slurry for stacked tunnel construction according to claim 5, characterized in that: The nano material is selected from one or both of nano silicon dioxide and nano clay.

7. A method for using the shield machine drag reduction slurry for stacked tunnel construction according to any one of claims 1 to 6, characterized in that: The method of use comprises the following steps: Step 1, weighing bentonite, sodium carbonate and water, mixing, stirring for reaction, and then standing for expansion to obtain drag-reducing mud; Step 2: During the advancement of the shield machine, add drag-reducing slurry to the outside of the shield shell. When the segment is separated from the shield tail, perform secondary grouting, and perform grouting again every two rings.

8. The method of use according to claim 7, characterized in that: In step 1, Mix the weighed bentonite, sodium carbonate and water, stir and react at room temperature for 0.5 to 1 hour, and then stand and expand for 1 to 3 hours. Lubricant and nano-material are added to the statically expanded mud, and the mixture is evenly mixed to obtain drag-reducing mud.

9. The method of use according to claim 7, characterized in that: In step 2, The amount of grouting each time is 130% to 180% of the theoretical amount of grouting. The theoretical amount of grouting is calculated according to formula (1): V=π× (D1 2 -D2 2 ) / 4×L Formula (1); In formula (1), V is the theoretical grouting volume; D1 is the outer diameter of the cutterhead; D2 is the outer diameter of the segment; L is the excavation length of each ring.

10. The method of use according to claim 7, characterized in that: In step 2, The pressure of adding drag reduction slurry and grouting is calculated according to formula (2) and formula (3): s z =γh=γ1h1+γ2h2+γ3h3 Equation (3); In formula (2) and formula (3): γ: soil density; h: soil layer thickness; φ: internal friction angle; σ: pressure.

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