High waterproof synchronous grouting grout for subsea shield tunnel

Abstract

The invention provides a high-waterproofness synchronous grouting slurry for submarine shield tunnels. The high-waterproofness synchronous grouting slurry comprises the following components as raw materials in percent by weight: 7.0-9.5% of a cementing material, 14.5-17.5% of ground limestone powder, 2.6-4.2% of sodium-based bentonite, 55-60% of river sand, a waterproofing agent of which the usingamount is 3.0% of that of the cementing material, a water reducing agent of which the using amount is 1.0% of that of the cementing material, hydroxypropyl methyl cellulose of which the using amountis 0.5% of that of the cementing material, polyacrylamide of which the using amount is 0.1% of that of the cementing material, an air entraining agent of which the using amount is 0.03% of that of thecementing material, and the balance of water, wherein the cementing material comprises cement and slaked lime according to a mass ratio of (4.0-5.5):(3.0-4.0). The high-waterproofness synchronous grouting slurry provided by the invention has relatively high waterproofness, relatively high early shear strength and strong seawater seepage resistance, and can provide certain shear resistance, so that the problems of floating of duct pieces and cracking-caused water seepage can be effectively solved and a role in stabilizing the duct piece is played.

Description

technical field [0001] The invention relates to the field of building materials, in particular to a high-waterproof synchronous grouting grout for subsea shield tunnels. Background technique [0002] Shield tunnel construction is becoming more and more common in the construction of urban subways and high-speed railways, especially in areas such as crossing rivers and bays, which further reflects the superiority of shield tunnel construction. Synchronous grouting is the key to the success of shield tunneling. The grout fills the gap between the back of the segment and the ground, thereby stabilizing the segment and forming a waterproof layer to prevent the infiltration of groundwater. [0003] In the shield construction in the bay area, due to the abundant water in the stratum and the destructive effect of salt in the groundwater, after the segment is pushed out of the shield tail of the shield machine, the segment often floats, cracks, and seeps. However, traditional grout,...

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Problems solved by technology

However, traditional grout, such as single-liquid grout, has a long gel time, high water separation rate, and poor groundwater corrosion resistance. After grouting, it is equivalent to supplementing the formation water content in a short period of time, which increases the buoyancy of the segment and is more likely to cause damage to the segment. The piece floats up and cracks. Once the piece cracks, seawater enters the concrete through the crack, causing serious corrosion to the steel bar, greatly reducing the service life of the structure, endangering the safety of the structure, and bringing huge safety hazards.

[0004] At present, the synchronous grouting of shield tunneling in China is still mainly based on cement (adding fly ash) mortar. This type of slurry has good fluidity, but often has a low stone formation rate and poor dilution resistance. In strata rich in groundwater, the slurry is easy to Diluted, no coagulation for a long time, and large shrinkage after consolidation, there is a large gap behind the segment

The buoyancy of the segment after it escapes from the tail of the shield is related to the volume of the displaced water. It is difficult for such slurry to provide shear resistance after being diluted. It is easier to cause the segment to float

European countries mostly use inert slurry, with lime as the cementitious material. This type of slurry is characterized by long usable time and small volume shrinkage, but has disadvantages: 1) Low early strength and low early shear resistance, which is not conducive to rich water Stability of Shield Segments in Formation

3) When the slump is large, the anti-dilution ability is poor, and it is easy to be diluted in the water-rich formation, and cannot stabilize the segment.

Japan mostly uses double-liquid slurry, which uses cement mortar and water glass as raw materials. There are disadvantages: 1) The construction is complicated, and the operation level of construction equipment and personnel is high; 2) It is easy to block pipes, which is inconvenient to promote, and domestic construction is rarely used.

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