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CN-121609553-B - Grouting slurry and synchronous grouting method suitable for shield construction of large-gradient section of water-rich sandy pebble stratum

CN121609553BCN 121609553 BCN121609553 BCN 121609553BCN-121609553-B

Abstract

The application relates to grouting slurry and a synchronous grouting method suitable for shield construction of a large-gradient section of a water-rich sand pebble stratum, and relates to the technical field of shield construction, wherein A liquid comprises 40-60 kg/m 3 of slaked lime, 500-650 kg/m 3 of fly ash, 70-90 kg/m 3 of sodium bentonite, 900-1100 kg/m 3 of sand, 1.5-2.5 kg/m 3 of polystyrene, 2-3 kg/m 3 of silica powder, 0.005-0.01 kg/m 3 of hydroxypropyl methyl cellulose, 300-320 kg/m 3 of water, 25-40L/m 3 of water glass, 5-10L/m 3 of polyacrylamide solution and 0.5-1.5 kg/m 3 of modified polycarboxylate. The slurry with specific components and proportion can effectively solve the dispersion resistance problem in the rich water environment, and can effectively prevent the pipe piece from floating upwards and improve the tunnel forming quality by combining with a specific grouting process.

Inventors

  • ZHAO XIAOPING
  • HU JUN
  • LUO CHAO
  • XIAO FAN
  • YE QING
  • ZHU XIAOFENG
  • Qing lang
  • Du Chunlang
  • ZHA YAN

Assignees

  • 中铁隧道局集团路桥工程有限公司
  • 中铁城市发展投资集团有限公司
  • 四川成德轨道交通有限公司

Dates

Publication Date
20260512
Application Date
20260203

Claims (9)

  1. 1. The grouting slurry is suitable for shield construction of a large-gradient section of a water-rich sand pebble stratum and is characterized in that raw materials of the grouting slurry comprise liquid A and liquid B, wherein the volume of each ring of grouting amount is 3.8-m 3 , the raw materials of the liquid A comprise slaked lime 40-60 kg/m 3 , fly ash 500-650 kg/m 3 , sodium bentonite 70-90 kg/m 3 , sand 900-1100 kg/m 3 , polystyrene 1.5-2.5 kg/m 3 , silicon powder 2-3 kg/m 3 , hydroxypropyl methylcellulose 0.005-0.01 kg/m 3 and water 300-320 kg/m 3 , and the raw materials of the liquid B comprise water glass 25-40L/m 3 , polyacrylamide solution 5-10L/m 3 and modified polycarboxylate 0.5-1.5 kg/m 3 ; wherein, the preparation method of the modified polycarboxylate comprises the following steps: (1) Mixing polyethylene glycol monomethyl ether acrylate with water at 40-50 ℃, and then mixing the mixed system, acrylic acid and 2-acrylamide-2-methylpropanesulfonic acid to form a monomer mixed solution; (2) Dropwise adding an initiator solution into the monomer mixed solution at 65-70 ℃ for polymerization reaction, adding thioglycollic acid into the polymerization reaction product when the viscosity of the polymerization reaction product is 800-1200 mPa.s, heating to 75-80 ℃ for reaction, cooling to 40-50 ℃ after the reaction is finished, and regulating the pH value to 6.0-7.0; (3) Mixing and reacting the system with the pH value adjusted in the step (2) with a silane coupling agent, wherein the content of the silane coupling agent is 1-2% based on 100% of the total mass of the system with the pH value adjusted; (4) Filtering the reaction product in the step (3), and spray-drying the filtrate obtained by filtering to obtain the modified polycarboxylate.
  2. 2. The grouting slurry of claim 1, wherein the dosage ratio of polyethylene glycol monomethyl ether acrylate, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, initiator solution and thioglycollic acid is 1 g:10~12 mL:3~6 g:10~25 mL:1~10 mL.
  3. 3. The grouting slurry according to claim 1, wherein the fly ash is class II fly ash, the fineness modulus of the sand is 0.5-1.5, the average particle diameter of the polystyrene is less than or equal to 50 μm, the content of SiO 2 in the silica powder is more than or equal to 90%, and the viscosity of the hydroxypropyl methylcellulose is 20000-40000 mPa-s; The polyacrylamide solution is a mixed solution of anionic polyacrylamide and water, wherein the molecular weight of the anionic polyacrylamide is 800-1200 ten thousand.
  4. 4. The method for synchronously grouting the shield construction of the large-gradient section of the water-rich sandy pebble stratum is characterized by comprising the following steps of: S1, acquiring construction data in real time in a construction process, wherein the construction data comprises soil pressure, gradient, groundwater flow speed, pipe piece rolling angle and grouting pressure; S2, constructing a grouting amount dynamic compensation model by using the construction data, wherein the grouting amount dynamic compensation model is shown in a formula (1): q d =Q b ×[1+K p ×(θ-θ 0 )+K v ×(v-v 0 ) ] type (1) In the formula (1), Q d represents the adjusted grouting amount, Q b represents the basic grouting amount before adjustment, K p represents the gradient compensation coefficient, K p is 0.015/mill, K v represents the flow rate compensation coefficient, K v is 0.1, θ represents the real-time gradient value, θ 0 represents the initial gradient value, v represents the real-time groundwater flow rate, and v 0 represents the initial groundwater flow rate; S3, dynamically adjusting grouting quantity of the to-be-grouting area in the construction process according to the grouting quantity dynamic compensation model, the real-time gradient value of the to-be-grouting area and the real-time groundwater flow speed, wherein grouting slurry used in the to-be-grouting area in the construction process is the grouting slurry suitable for the shield construction of the large-gradient area of the water-rich sandy pebble stratum according to any one of claims 1-3.
  5. 5. The method for synchronously grouting the shield construction of the large-gradient land section suitable for the water-rich sandy pebble stratum according to claim 4, wherein when the land section to be grouting is an uphill section, grouting holes of the uphill section comprise a top grouting hole, a bottom grouting hole and a side grouting hole, and the total grouting amount of the uphill section is 100%, the grouting amount of the top grouting hole is 60-70%, the grouting amount of the bottom grouting hole is 20-30%, and the grouting amount of the side grouting hole is 5-15%.
  6. 6. The method for synchronously grouting the shield construction of the large-gradient land section suitable for the water-rich sandy pebble stratum according to claim 5, wherein when the land section to be grouting is a downhill section, grouting holes of the downhill section comprise a top grouting hole, a bottom grouting hole and a side grouting hole, wherein the total grouting amount of the downhill section is 100%, the grouting amount of the top grouting hole is 20-40%, the grouting amount of the bottom grouting hole is 40-60%, and the grouting amount of the side grouting hole is 10-30%.
  7. 7. The method for synchronously grouting shield construction of the large-gradient section of the water-rich sandy pebble stratum according to claim 6 is characterized in that when the section to be grouting is an uphill section, grouting slurry used by the top grouting hole is mixed liquid of A liquid and B liquid with the mass ratio of 3-5:1, grouting slurry used by the bottom grouting hole is mixed liquid of A liquid and B liquid with the mass ratio of 2-4:1, and grouting slurry used by the side grouting hole is mixed liquid of A liquid and B liquid with the mass ratio of 1-3:1.
  8. 8. The method for synchronously grouting shield construction of the large-gradient section of the water-rich sandy pebble stratum according to claim 6 is characterized in that when the section to be grouting is a downhill section, grouting slurry used by the top grouting hole is mixed liquid of A liquid and B liquid with the mass ratio of 4-6:1, grouting slurry used by the bottom grouting hole is mixed liquid of A liquid and B liquid with the mass ratio of 2-4:1, and grouting slurry used by the side grouting hole is mixed liquid of A liquid and B liquid with the mass ratio of 1-3:1.
  9. 9. The method for synchronous grouting for shield construction of a large-gradient land section of a water-rich sandy pebble stratum according to claim 6, wherein when the land section to be grouting is an uphill section, the grouting pressure of the top grouting hole is 0.4-0.5 MPa, the grouting pressure of the bottom grouting hole is less than or equal to 0.2 MPa, and the grouting pressure of the side grouting hole is 0.3-0.35 MPa; When the section to be grouting is a downhill section, the grouting pressure of the top grouting hole is 0.25-0.3 MPa, the grouting pressure of the bottom grouting hole is 0.35-0.4 MPa, and the grouting pressure of the side grouting hole is 0.3-0.35 MPa.

Description

Grouting slurry and synchronous grouting method suitable for shield construction of large-gradient section of water-rich sandy pebble stratum Technical Field The application relates to the technical field of shield construction, in particular to grouting slurry and a synchronous grouting method suitable for shield construction of a large-gradient region of a water-rich sand pebble stratum. Background The shield construction has become one of the key methods for underground space construction such as urban subways, river crossing tunnels and the like because of the remarkable advantages of high mechanization degree and small disturbance to surrounding stratum. In the construction of a shield tunnel, the annular gap generated by synchronous grouting filling shield tunneling is a key construction measure for ensuring the safety of a structure and controlling the relative displacement of earth surface subsidence and a segment. Conventional synchronous grouting processes and traditional slurry formulations have been widely used and validated in areas where the rock and soil conditions are relatively uniform and the gradient is small, but conventional synchronous grouting processes and traditional slurry formulations face a number of technical challenges when encountering water-rich sandy pebble formations, aided by large gradient areas. The water-rich sandy pebble stratum has coarse grain composition, large void ratio, high permeability coefficient and strong mobility of underground water, so that the problems of easy quick filtration loss of slurry, elution of slurry, difficult transfer of grouting pressure, passive loss and the like are caused, and the grouting efficiency is reduced, and a continuous, uniform and bearing slurry wrapping layer is difficult to form. Meanwhile, the gravity drive caused by the large gradient makes the slurry flow asymmetrically in the pore, the slurry stays at the tail of the slurry accumulation shield in the uphill region and the slurry aggregation shield in the downhill region, so that uniform filling of grouting slurry is difficult to ensure, the stratum cannot be effectively reinforced, and the risks of floating up of the segment, dislocation, uneven internal stress of the annular gap and local surface bulge or subsidence are easily increased. Synchronous grouting is used as a key means for filling the gaps of the shield tails and stabilizing surrounding rocks, and slurry with gelling and solidifying characteristics is instantly injected into gaps between the segments and the stratum to form a circumferential support body so as to counteract stress release of the stratum, control water and soil loss and strengthen the stratum. In the prior art, fly ash-bentonite inert slurry or cement-based single-liquid slurry is generally adopted, grouting parameter setting depends on an empirical value, and construction requirements can be basically met in a homogeneous stratum. However, when the cement-based slurry is applied to a water-rich sandy pebble stratum tunnel, the traditional slurry component lacks water-resistant dispersion materials, the slurry is difficult to retain, so that the slurry is greatly lost along the sandy pebble pores and cannot effectively block a seepage path, the cement-based slurry is delayed in setting time, the slurry loss rate is high due to overlong final setting time, the strength is insufficient after the slurry is formed, and the floating displacement overrun of a duct piece is induced. Meanwhile, the existing grouting process is poor in adaptability to the working condition of a large gradient, a symmetrical grouting mode is often adopted in the traditional grouting process, the influence of gravity effect and groundwater seepage existing in a large gradient section in a water-rich sandy pebble stratum is not considered, and the problems of floating of a duct piece and uneven grouting of the large gradient section cannot be effectively restrained. The problems seriously affect the forming quality and the safety of the tunnel, so that the current construction of the large-gradient shield in the water-rich sandy pebble stratum faces the risks of segment staggering, surface subsidence and the like for a long time. Although the chinese patent CN111779494a proposes a grouting method for controlling the floating of the segment in the shield construction, the method is not suitable for the water-rich sandy pebble stratum, and the method is improved on the traditional grouting process, but is only suitable for the homogeneous stratum, and the method does not consider the influence of the shield gradient, and the compensating mechanism of the pressure cannot cope with the floating component of the segment caused by the large gradient segment. The water-rich sandy pebble stratum is a heterogeneous mixture composed of sand, pebbles and a small amount of clay with obvious particle size difference, and has high stratum permeability coefficient and high groundwater f