Filler for shield construction, and shield construction method

Abstract

To provide a filler for shield construction having a new function of not only reducing frictional resistance force generated between a shield tunneling machine and natural ground during shield construction but also reducing vibration and noise generated by the shield construction.SOLUTION: A filler for shield construction used in shield construction includes a water-insoluble superabsorbent polymer and a water-soluble thickener. The superabsorbent polymer includes a granular superabsorbent polymer and a fine powder superabsorbent polymer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filler for shield construction used in shield construction, and a shield construction method using the filler for shield construction. [Background technology]

[0002] In shield construction, in which a tunnel is constructed by excavating the ground with a shield machine, attempts have been made to reduce the frictional resistance that occurs between the shield machine and the natural ground. A typical friction reduction method is to pressurize a lubricant between the shield machine and the natural ground (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a technique for an excavation method using a shield machine (referred to in the document as a "shield machine") in which a gelled material based on water-absorbent polymer or bentonite is injected as a lubricant between the outer shell of the shield machine and the natural ground. According to Patent Document 1, this lubricant is effective in reducing the frictional force between the outer shell of the shield machine and the natural ground when excavating a tunnel with a small earth covering section. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-9566 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the functions required of filler materials in shield tunneling have become more diverse. Conventional filler materials, as described in Patent Document 1, were primarily intended to reduce friction. However, as tunnel construction becomes deeper, larger in cross-sectional area, and longer in distance, and due to growing environmental awareness among local residents, the generation of vibrations and noise has become a problem. When vibrations are generated by an underground shield tunneling machine, these vibrations are transmitted through the ground to the surface. If the vibrations generated underground are large, they may be detectable by people on the surface. Furthermore, the transmitted vibrations may be transmitted to components such as buildings, generating noise from those components. However, no filler materials for shield tunneling to date have focused on reducing vibrations and noise.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a filler for shield tunneling that has a new function of not only reducing the frictional resistance generated between the shield tunneling machine and the natural ground during shield tunneling, but also reducing the vibration and noise generated by the shield tunneling. It also aims to provide a shield tunneling method using the filler for shield tunneling. [Means for solving the problem]

[0007] The characteristic configuration of the shield construction filler according to the present invention to solve the above problems is as follows: A filler for shield construction used in shield construction, a highly absorbent polymer that is insoluble in water; A water-soluble thickener Including, The superabsorbent polymer includes a granular superabsorbent polymer and a fine powder superabsorbent polymer.

[0008] When water is added to the shield tunneling filler to make it usable in shield tunneling, the superabsorbent polymer absorbs water and swells, and the thickener dissolves in water to form a viscous liquid. This results in the shield tunneling filler being in a state (dispersion) in which swollen superabsorbent polymers are dispersed in the viscous liquid. The superabsorbent polymers include granular superabsorbent polymers and finely divided superabsorbent polymers. Granular superabsorbent polymers with relatively large particle sizes absorb water and swell, making them less likely to penetrate into gaps in the soil and sand that make up the natural ground. This acts as a cushion between the natural ground and the shield tunneling machine, reducing the contact area between the natural ground and the shield tunneling machine and reducing friction, thereby suppressing vibration and noise. Finely divided superabsorbent polymers with relatively small particle sizes absorb water and swell, penetrating into gaps in the soil and sand that make up the natural ground, blocking the natural ground and preventing the dispersion from leaking, thereby providing an antifriction effect. In this way, by using the shield construction filler of this configuration in shield construction, not only can the frictional resistance force generated between the shield tunneling machine and the ground be reduced, but the vibrations and noise generated by shield construction can also be reduced.

[0009] In the shield construction filling material according to the present invention, The granular superabsorbent polymer has a particle size distribution peak of 0.425 mm or more, The finely divided highly water-absorbent polymer preferably has a particle size distribution peak of less than 0.075 mm.

[0010] With this type of shield construction filler, the peaks of the particle size distribution of the granular superabsorbent polymer and the particle size distribution of the fine powder superabsorbent polymer are spaced apart on either side of the particle diameter of 0.075 mm, which is the boundary between fine and coarse particles in soil and sand. This means that the vibration and noise reduction effect of the granular superabsorbent polymer and the frictional resistance reduction effect of the fine powder superabsorbent polymer can both be clearly felt.

[0011] In the shield construction filling material according to the present invention, The granular superabsorbent polymer has a D90 particle size of more than 0.850 mm; The finely powdered highly water-absorbent polymer preferably has a D90 particle size between 0.106 and 0.250 mm.

[0012] With this type of shield construction filler, the D90 particle diameter of the granular superabsorbent polymer and the D90 particle diameter of the fine powder superabsorbent polymer are separated from each other, so that the vibration and noise reduction effect of the granular superabsorbent polymer and the frictional resistance reduction effect of the fine powder superabsorbent polymer can be clearly felt.

[0013] In the shield construction filling material according to the present invention, The granular superabsorbent polymer has a particle size of 100 mesh or more, The finely divided superabsorbent polymer preferably has a particle size of less than 100 mesh.

[0014] With this type of shield construction filler, the particle size of 100 mesh is used as the boundary between granular superabsorbent polymer and fine powder superabsorbent polymer, so that the vibration and noise reduction effect of the granular superabsorbent polymer and the frictional resistance reduction effect of the fine powder superabsorbent polymer can be clearly felt.

[0015] In the shield construction filling material according to the present invention, The blending ratio of the granular highly absorbent polymer to the fine powder highly absorbent polymer is preferably 1:0.5 to 1:3.

[0016] With this type of shield construction filler, the mixing ratio of granular superabsorbent polymer to fine powder superabsorbent polymer is set within the appropriate range described above, so that it is possible to achieve both the vibration and noise reduction effect of the granular superabsorbent polymer and the frictional resistance reduction effect of the fine powder superabsorbent polymer.

[0017] In the shield construction filling material according to the present invention, The highly water-absorbent polymer is preferably a polyacrylic acid polymer and / or a polymethacrylic acid polymer.

[0018] The shield construction filler of this configuration uses a polyacrylic acid polymer and / or a polymethacrylic acid polymer as the superabsorbent polymer, forming a swollen body of the superabsorbent polymer with adequate strength. This allows the swollen body to remain in the viscous liquid for a long period of time, thereby maintaining the vibration and noise reduction effects of the granular superabsorbent polymer and the friction resistance reduction effect of the fine powder superabsorbent polymer.

[0019] In the shield construction filling material according to the present invention, The thickener is preferably an anionic polyelectrolyte.

[0020] The shield tunneling filler of this configuration uses an anionic polyelectrolyte as a thickener, which allows the swollen superabsorbent polymer to aggregate appropriately in the viscous liquid formed by dissolving the thickener in water. As a result, even if there is a large resistance when filling the gap between the shield tunneling machine and the natural ground, the structure of the swollen superabsorbent polymer in the viscous liquid is less likely to break down, and the granular superabsorbent polymer provides a sustained reduction in vibration and noise, while the fine powder superabsorbent polymer provides a sustained reduction in frictional resistance.

[0021] In the shield construction filling material according to the present invention, The content of the thickener is preferably 1.5 to 15% by weight.

[0022] The shield construction filler of this configuration contains 1.5 to 15% by weight of thickener, so that when water is added, the swollen superabsorbent polymer is properly dispersed in the viscous liquid. As a result, the vibration and noise reduction effect of the granular superabsorbent polymer and the friction resistance reduction effect of the fine powder superabsorbent polymer are more effectively exhibited.

[0023] In the shield construction filling material according to the present invention, When water is added to prepare a liquid formulation with a concentration of 0.5 w / v %, the viscosity of the liquid formulation within 24 hours is preferably 1500 mPa·s or less.

[0024] With this type of shield construction filler, when the liquid is prepared, excessive increases in viscosity due to changes over time are suppressed, so that after the liquid is prepared by adding water at the construction site, it can maintain an appropriate viscosity for the entire day (24 hours).

[0025] In the shield construction filling material according to the present invention, It is preferable that the shield has damping properties to reduce vibrations and / or noise generated by shield construction.

[0026] The filler for shield construction of this configuration has damping properties that reduce the vibrations and / or noise generated by shield construction, making it possible to accommodate tunnel construction that is deeper, has a larger cross-sectional area, and is longer in distance.

[0027] The characteristic configuration of the shield tunneling method according to the present invention for solving the above problems is as follows: The method includes a filling step of filling the above-mentioned shield construction filler between the shield tunneling machine and the natural ground.

[0028] This shield tunneling method not only reduces the frictional resistance between the shield machine and the natural ground during shield construction, but also reduces the vibration and noise generated by shield construction, making it possible to accommodate tunnel construction that is deeper, has a larger cross-sectional area, and is longer in distance. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is an image diagram showing the state in which the filler for shield construction of the present invention is filled between a shield machine and the natural ground (overcut). [Figure 2] Figure 2 is a schematic diagram of the testing machine, which imitates the shield tunneling machine used in the vibration test. [Figure 3] FIG. 3 is a graph showing the results of measuring acceleration in the circumferential direction of the container using the testing machine. DETAILED DESCRIPTION OF THE INVENTION

[0030] The following describes embodiments of the filler for shield construction and the shield construction method of the present invention, but the present invention is not limited to the following.

[0031] [Filling material for shield construction] The filler for shield construction of the present invention is used in various shield constructions such as earth pressure shield construction, mud shield construction, and air bubble shield construction, and contains a highly water-absorbent polymer and a thickener.

[0032] As the superabsorbent polymer, a superabsorbent polymer insoluble in water is used. Examples of such superabsorbent polymers include polyacrylic acid polymers, polymethacrylic acid polymers, polyvinyl acetate polymers, and carboxymethyl cellulose polymers. Preferred superabsorbent polymers are polyacrylic acid polymers and polymethacrylic acid polymers. Preferred polyacrylic acid polymers include sodium polyacrylate. Preferred polymethacrylic acid polymers include sodium polymethacrylate.

[0033] A water-soluble thickener is used as the thickener. Anionic polyelectrolytes are preferred. A typical example of anionic polyelectrolytes is an anionic polymer flocculant. Examples of anionic polyelectrolytes include polycarboxylates or copolymers of polycarboxylates and acrylamide, polysulfonates or copolymers of polysulfonates and acrylamide, and derivatives thereof. Among these, copolymers of polycarboxylic acids and acrylamide are preferred. Examples of polycarboxylic acids for forming polycarboxylates include acrylic acid, methacrylic acid, itaconic acid, and maleic acid. Examples of polysulfonic acids for forming polysulfonates include acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, and styrenesulfonic acid. The molecular weight of the anionic polyelectrolyte is preferably 10,000,000 to 22,000,000. For example, anionic polymer flocculants with high anionicity and a molecular weight of 16 million to 22 million, anionic polymer flocculants with medium anionicity and a molecular weight of 13 million to 16 million, and anionic polymer flocculants with low anionicity and a molecular weight of 10 million to 13 million can be used.

[0034] The content of the thickener is preferably 1.5 to 15% by weight based on the total weight of the shield construction filler. When the shield construction filler contains 1.5 to 15% by weight of the thickener, adding water to the shield construction filler results in a state in which the swollen superabsorbent polymer is properly dispersed in the viscous liquid. As a result, the vibration and noise reduction effect of the granular superabsorbent polymer and the friction resistance reduction effect of the fine powder superabsorbent polymer are more effectively exhibited.

[0035] The shield construction filler of the present invention is usually distributed in the market as a powder, but for actual use at construction sites, water is added to the powder to form a liquid or slurry. The amount of water added is preferably 500 to 2000 L per 5 kg of shield construction filler (powder), and more preferably 1000 L per 5 kg of shield construction filler (powder). When an appropriate amount of water is added to the shield construction filler, the superabsorbent polymer contained in the shield construction filler absorbs water and swells, and the thickener dissolves in water to form a viscous liquid. This results in the shield construction filler being in a state where the swollen superabsorbent polymer is dispersed in the viscous liquid (dispersion or slurry). Furthermore, when water is added to the shield construction filler to prepare a liquid with a concentration of 0.5 w / v%, the viscosity of the liquid within 24 hours is preferably 1500 mPa·s or less. In this case, excessive increase in viscosity due to changes in the liquid over time is suppressed, so after the liquid is prepared by adding water at the construction site, it can maintain an appropriate viscosity all day (over 24 hours).

[0036] Here, superabsorbent polymers include granular polymers with relatively large particle sizes (granular superabsorbent polymers) and finely divided polymers with relatively small particle sizes (fine-powdered superabsorbent polymers). Granular superabsorbent polymers have a D90 particle size greater than 0.850 mm and a particle size distribution peak of 0.425 mm or greater. Fine-powdered superabsorbent polymers have a D90 particle size between 0.106 and 0.250 mm and a particle size distribution peak of less than 0.075 mm. Superabsorbent polymers can also be separated into granular and fine-powdered superabsorbent polymers using a 100-mesh (approximately 0.154 mm) sieve. That is, those with a particle size of 100 mesh or greater (0.154 mm or greater) are considered granular superabsorbent polymers, and those with a particle size of less than 100 mesh (less than 0.154 mm) are considered fine-powdered superabsorbent polymers. The particle size distribution of the granular superabsorbent polymer and the fine powder superabsorbent polymer will be exemplified in the examples given later.

[0037] Figure 1 is an illustration of the shield tunneling filler of the present invention filled between a shield machine and the natural ground (overcut). Note that Figure 1 is merely an illustration for easily understanding the relationship between the shield machine and the natural ground, and does not accurately reflect the particle sizes and relative positions of the soil and superabsorbent polymer. In particular, the enlarged view of the circle surrounded by the dashed line (in the figure in the speech bubble) exaggerates the soil and superabsorbent polymer present in the overcut. Granular superabsorbent polymers with relatively large particle sizes absorb water and swell, making it difficult for them to penetrate into the gaps between the soil (soil particles) that make up the natural ground. This acts as a cushion between the shield machine and the natural ground, reducing the contact area between the shield machine and the natural ground, thereby reducing friction and suppressing vibration and noise. Finely divided superabsorbent polymers with relatively small particle sizes absorb water and swell, penetrating into the gaps in the soil that make up the natural ground and blocking the natural ground. This prevents the dispersion from leaking, thereby providing an antifriction effect.

[0038] In this way, by using the shield construction filler of the present invention in shield construction, not only can the frictional resistance force generated between the shield tunneling machine and the ground be reduced, but the vibrations and noise generated by shield construction can also be reduced.

[0039] Furthermore, the particle size distribution peak of granular superabsorbent polymer (0.425 mm or more) and the particle size distribution peak of fine powder superabsorbent polymer (less than 0.075 mm) are located apart on either side of the particle size of 0.075 mm, which is considered the boundary between fine and coarse particles in soil and sand.Furthermore, the D90 particle size of granular superabsorbent polymer (more than 0.850 mm) and the D90 particle size of fine powder superabsorbent polymer (between 0.106 and 0.250 mm) are located apart, so the vibration and noise reduction effect of granular superabsorbent polymer and the frictional resistance reduction effect of fine powder superabsorbent polymer can each be clearly felt.

[0040] The blending ratio of the granular superabsorbent polymer to the fine powder superabsorbent polymer in the superabsorbent polymer is preferably 1:0.5 to 1:3, which allows both the vibration and noise reducing effect of the granular superabsorbent polymer and the frictional resistance reducing effect of the fine powder superabsorbent polymer to be achieved.

[0041] When a polyacrylic acid polymer and / or a polymethacrylic acid polymer is used as the superabsorbent polymer, a swollen body of the superabsorbent polymer with adequate strength is formed, which allows the swollen body to remain in the viscous liquid for a long period of time, thereby maintaining the vibration and noise reduction effects of the granular superabsorbent polymer and the friction resistance reduction effects of the fine powder superabsorbent polymer.

[0042] When an anionic polyelectrolyte is used as the thickener, the swollen superabsorbent polymer aggregates appropriately in the viscous liquid in which the thickener is dissolved in water. As a result, even if there is a large resistance when filling the gap between the shield machine and the natural ground, the structure of the swollen superabsorbent polymer in the viscous liquid is not easily broken down, and the vibration and noise reduction effects of the granular superabsorbent polymer and the frictional resistance reduction effect of the fine powder superabsorbent polymer are continuously exerted.

[0043] As described above, the filler for shield construction of the present invention contains a superabsorbent polymer and a thickener, and therefore has damping properties that reduce vibration and / or noise generated by shield construction. This not only reduces the frictional resistance between the shield machine and the natural ground during shield construction, but also reduces the vibration and noise generated by shield construction. Therefore, it is possible to accommodate tunnel construction that is becoming deeper, larger in cross-sectional area, and longer in distance.

[0044] [Shield tunneling method] The shield tunneling method of the present invention carries out a filling step in which the above-mentioned filler material for shield tunneling of the present invention is filled between the shield tunneling machine and the natural ground. The filling step is carried out by supplying the filler material for shield tunneling to the shield tunneling machine and injecting it into the gap between the shield tunneling machine and the natural ground (overcut) from a valve provided on the skin plate of the shield tunneling machine. [Example]

[0045] The filler for shield construction of the present invention will be explained in more detail by showing examples.

[0046] [Preparation of filler (powder) for shield construction] The following chemicals were used as components of the filler for shield construction. Superabsorbent Polymer (SAP) Main ingredient: Sodium polyacrylate [granular SAP, fine powder SAP] (manufactured by Technica Godo Co., Ltd.) · Thickener (anionic polymer flocculant) Main ingredient: Polycarboxylic acid-acrylamide copolymer (manufactured by Technica Godo Co., Ltd.) The particle size distributions of the granular superabsorbent polymer and the fine powder superabsorbent polymer are shown in Table 1 below.

[0047] [Table 1]

[0048] The superabsorbent polymer and thickener, which were prepared by varying the blending ratio of granular superabsorbent polymer to fine powder superabsorbent polymer, were mixed at a predetermined blending ratio to prepare the fillers (powders) for shield construction of Examples 1 to 4 shown in the "Powder Blend" column of Table 2 below. The fillers (powders) of Comparative Examples 1 and 2 were also prepared in the same manner. The thickener contents of the fillers (powders) for shield construction of Examples 1 to 4 and the fillers (powders) of Comparative Examples 1 and 2 were 14.3 wt% (Example 1), 11.1 wt% (Example 2), 4.8 wt% (Example 3), 2.0 wt% (Example 4), 66.6 wt% (Comparative Example 1), and 66.8 wt% (Comparative Example 2).

[0049] [Preparation of filler (liquid) for shield construction] 5 g of the filler (powder) for shield construction was added little by little to a mixer containing water, and the total volume was adjusted to 1 L (concentration: 0.5 w / v%). The mixture was then stirred for 10 minutes in the mixer to prepare the filler (liquid) for shield construction of Examples 1 to 4. The fillers (liquid) of Comparative Examples 1 and 2 were also prepared in the same manner.

[0050] [Performance and effectiveness confirmation test] In order to confirm the performance and effect of the filler for shield construction of the present invention, a viscosity test, a tensile friction test, a ground penetration test, a vibration test, and a noise test were carried out.

[0051] <Viscosity test> The viscosity of the shield construction filler (liquid) of Examples 1 to 4 was measured using a B-type viscometer (model: BM, manufactured by Toki Sangyo Co., Ltd.). The same viscosity tests as in the Examples were also conducted on the filler (liquid) of Comparative Examples 1 and 2, which contained a superabsorbent polymer (containing either a granular superabsorbent polymer or a fine powder superabsorbent polymer) and a thickener. Furthermore, as Reference Example 1, a similar viscosity test was conducted using a lubricant for a conventional jacking method whose main component is a superabsorbent polymer. The results of the viscosity test are shown in Table 2 below.

[0052] [Table 2]

[0053] As shown in Table 2, the shield construction fillers of Examples 1 to 4, which contain superabsorbent polymers including granular superabsorbent polymers and finely divided superabsorbent polymers, and a thickener, had sufficiently low viscosities immediately after preparation and maintained their low viscosities even after a certain period of time had passed. In contrast, the filler of Comparative Example 1, which contained finely divided superabsorbent polymers as the superabsorbent polymer but not granular superabsorbent polymers, had a very high viscosity immediately after preparation and further increased over time. The filler of Comparative Example 2, which contained granular superabsorbent polymers as the superabsorbent polymer but not finely divided superabsorbent polymers, had a high viscosity immediately after preparation and further increased over time. Thus, the shield construction fillers of Examples 1 to 4, which correspond to the present invention, can be said to be suitable for shield construction work that is carried out over a long period of time because the increase in viscosity is suppressed immediately after preparation for a long period of time. Incidentally, the lubricant for the jacking method of Reference Example 1 had an extremely high viscosity immediately after preparation, making it difficult to apply to shield construction work.

[0054] <Tension and friction test> The fillers (liquid) for shield construction of Examples 1 to 4, the fillers (liquid) of Comparative Examples 1 and 2, and the lubricant for jacking construction of Reference Example 1 used in the viscosity test were subjected to a tensile friction test using the following procedure. (1) Apply filler to the steel plate (application amount: 6 L / m 2 , 1m 2 (Applied to a thickness of 6mm). (2) A brick (21 cm long, 10 cm wide, 3 cm thick, 1.25 kg mass) is placed on the iron plate coated with the filler as a test piece. (3) One end of a strong string is attached to the brick, and the other end is attached to a force gauge (model: DST-500N, manufactured by Imada Co., Ltd.) that can slide at a constant speed. The force gauge is then slid horizontally at a speed of 10 mm / min to pull the brick. (4) Read the maximum tensile load indicated on the force gauge while the brick is moving. (5) The maximum tensile load is measured three times, and the average value is used as the tensile friction stress. The results of the tensile friction test are shown in Table 3 below.

[0055] [Table 3]

[0056] As shown in Table 3, the shield construction fillers of Examples 1 to 4, which contained superabsorbent polymers including granular superabsorbent polymer and finely divided superabsorbent polymer, and a thickener, had sufficiently low tensile friction stress. In contrast, the filler of Comparative Example 1, which contained finely divided superabsorbent polymer as the superabsorbent polymer but no granular superabsorbent polymer, had a very high tensile friction stress. The filler of Comparative Example 2, which contained granular superabsorbent polymer as the superabsorbent polymer but no finely divided superabsorbent polymer, had a high tensile friction stress. Thus, the shield construction fillers of Examples 1 to 4, which correspond to the present invention, have sufficiently low tensile friction stress and are therefore suitable for shield construction work carried out over long distances. Incidentally, the lubricant for the jacking method of Reference Example 1 had low tensile friction stress, but as mentioned above, its extremely high viscosity made it difficult to handle in shield construction work.

[0057] <Ground penetration test> Ground penetration tests were conducted using the following procedure for the shield construction fillers (liquid) of Examples 1 to 4, the fillers (liquid) of Comparative Examples 1 and 2, and the slipper for the jacking method of Reference Example 1 used in the viscosity test and tensile friction test. (1) Fill the chamber (diameter 77 mm, height 135 mm) of a pressure filtration testing machine (model: S-250, manufactured by Nishinippon Testing Machine Co., Ltd.) with 100 cc of sand (average particle size approximately 0.06 mm) as simulated ground, and then quickly pour the filler material from above up to the top of the opening of the chamber. (2) Discharge the filler (filtrate) from the bottom of the chamber. (3) When the discharge of the filler material stops, measure the distance from the top of the chamber opening to the liquid surface of the filler material (the drop before pressurization). (4) The chamber is sealed and pressurized at 0.3 MPa for 7.5 minutes, and the filler is discharged from the bottom of the chamber. (5) Once the discharge of the filler material has stopped, open the chamber and measure the distance from the top of the chamber opening to the liquid surface of the filler material (the drop after pressurization). (6) Calculate the difference between the drop after pressure and the drop before pressure (first time). (7) Repeat the above steps (1) to (6) again (for the second time), and determine the average value of the difference between the sag after pressure application and the sag before pressure application for the first and second times as the ground permeability. The results of the ground infiltration test are shown in Table 4 below.

[0058] [Table 4]

[0059] As shown in Table 4, the shield construction fillers of Examples 1 to 4, which contained superabsorbent polymers including granular superabsorbent polymer and fine powder superabsorbent polymer, and a thickener, had sufficiently small ground permeability (the difference between the sag after pressurization and the sag before pressurization). In contrast, the filler of Comparative Example 1, which contained fine powder superabsorbent polymer as the superabsorbent polymer but not granular superabsorbent polymer, had a large ground permeability. The filler of Comparative Example 2, which contained granular superabsorbent polymer as the superabsorbent polymer but not fine powder superabsorbent polymer, had a very large ground permeability. Thus, the shield construction fillers of Examples 1 to 4, which correspond to the present invention, have sufficiently small ground permeability and are therefore suitable for shield construction work carried out over a long period of time. Incidentally, the slipper for the jacking method of Reference Example 1 had a small ground permeability, but as mentioned above, its extremely high viscosity made it difficult to handle in shield construction work.

[0060] <Vibration test 1> A laboratory vibration test (referred to as Vibration Test 1) was conducted using the shield construction filler (liquid) of Example 3 used in the viscosity test, tensile friction test, and ground penetration test. In addition, as Comparative Example 3, a similar Vibration Test 1 was conducted under conditions in which no lubricant was used.

[0061] Vibration Test 1 was conducted using a testing machine simulating a shield tunneling machine, as shown in Figure 2. The testing machine has a structure in which an airtight container containing simulated soil is fixed on top of a rotary table. The simulated soil used was sand and gravel from a construction site where significant vibrations were observed on the ground surface. Prior to Vibration Test 1, the moisture content of the simulated soil was adjusted appropriately, and it was poured into the airtight container in five layers and compacted from above to form a simulated ground layer inside the airtight container.

[0062] A hollow steel casing, representing a shield tunneling machine, was penetrated into the simulated ground (simulated soil) in a sealed container at a constant speed (10 mm / min), while the rotating table was rotated at 1 rpm, recreating the conditions of a shield tunneling machine advancing while digging underground. Accelerometers and other measuring instruments were installed on the testing machine in the positions shown in Figure 2, allowing for the measurement of thrust, rotational torque, and vibration as the steel casing penetrated the simulated ground. During the test, the shield tunneling filler material was constantly pressurized to 0.3 MPa by a compressor and discharged from two ports on the side of the steel casing using a metering pump. It was then injected into the over-excavation gap (approximately 3 mm) formed between the steel casing and the simulated ground. The volume of shield tunneling filler delivered was set to twice the volume of the over-excavation.

[0063] The results of vibration test 1 are shown in Table 5 below and Figure 3. Table 5 shows the measurement results of the thrust force (thrust force at penetration) and rotational torque when the steel casing penetrated the simulated ground. Figure 3 is a graph showing the acceleration measurement results in the circumferential direction of the container of the testing machine.

[0064] [Table 5]

[0065] As shown in Table 5, when excavating simulated ground, the use of the shield construction filler of Example 3, which contains a superabsorbent polymer including a granular superabsorbent polymer and a fine powder superabsorbent polymer, and a thickener, can reduce the thrust and rotational torque during penetration into the simulated ground compared to Comparative Example 3, in which the simulated ground was excavated without using a slipper.

[0066] In addition, as shown in Figure 3, in Comparative Example 3, where the simulated ground was excavated without using a sliding material, the maximum acceleration in the circumferential direction of the container was 0.1 m / s 2 The average amplitude of the acceleration was 0.030 m / s 2 It is assumed that this large acceleration was caused by the steel casing, which had been restrained by earth pressure, being released by the rotation of the container, resulting in vibration. In contrast, when the simulated ground was excavated using the shield construction filler material of Example 3, the maximum acceleration was 0.040 m / s 2 The average amplitude of the acceleration does not exceed 0.013 m / s 2 As described above, it was confirmed that when the filler for shield construction of Example 3 was used, the acceleration in the circumferential direction of the container was reduced by 50% or more compared to Comparative Example 3, which did not use a lubricant. The reason for this is presumably that, by filling the filler for shield construction around the steel casing, the filler for shield construction acts as a cushion between the simulated ground (natural ground) and the shield tunneling machine, and the contact area between the simulated ground (natural ground) and the steel casing is reduced, thereby reducing frictional force and suppressing the occurrence of large vibrations.

[0067] <Vibration test 2> Next, an on-site vibration test (referred to as Vibration Test 2) was conducted. In Vibration Test 2, the vibration acceleration level generated when the shield construction filler (liquid) of Example 3 was used was measured. In addition, the vibration acceleration level generated when a jacking construction lubricant (mainly composed of acrylic copolymer) was used as Comparative Example 4 was measured. As a result, although the data is not presented, it was found that the vibration acceleration level generated when the shield construction filler (liquid) of Example 3 was used was 10 dB or more lower than the vibration acceleration level generated when the jacking construction lubricant of Comparative Example 4 was used.

[0068] As such, the filler for shield construction of the present invention can significantly reduce the vibrations generated during excavation, which naturally suggests that the impact of noise on buildings on the ground will also be reduced. [Industrial Applicability]

[0069] The shield tunneling filler and shield tunneling method of the present invention can be used in civil engineering works carried out using shield tunneling machines, i.e., various shield tunneling works such as mud pressure shield tunneling, mud shield tunneling, and air bubble shield tunneling.

Claims

1. A filler for shield construction used in shield construction, a highly absorbent polymer that is insoluble in water; A water-soluble thickener Including, The superabsorbent polymer is a filler for shield construction, which contains a granular superabsorbent polymer and a fine powder superabsorbent polymer.

2. The granular superabsorbent polymer has a particle size distribution peak of 0.425 mm or more, 2. A filler for shield construction according to claim 1, wherein the fine powder of the highly absorbent polymer has a particle size distribution peak of less than 0.075 mm.

3. The granular superabsorbent polymer has a D90 particle size of more than 0.850 mm, 2. A filler for shield construction according to claim 1, wherein the fine powder highly absorbent polymer has a D90 particle size between 0.106 and 0.250 mm.

4. The granular superabsorbent polymer has a particle size of 100 mesh or more, 2. A filler for shield construction according to claim 1, wherein the fine powder of highly absorbent polymer has a particle size of less than 100 mesh.

5. 2. A filler for shield construction according to claim 1, wherein the blending ratio of said granular superabsorbent polymer to said fine powder superabsorbent polymer is 1:0.5 to 1:

3.

6. 2. A filler for shield construction according to claim 1, wherein the highly water-absorbent polymer is a polyacrylic acid-based polymer and / or a polymethacrylic acid-based polymer.

7. 2. The filler for shield construction according to claim 1, wherein the thickener is an anionic polyelectrolyte.

8. 2. A filler for shield construction according to claim 1, wherein the content of the thickener is 1.5 to 15% by weight.

9. 2. A filler for shield construction according to claim 1, wherein when water is added to prepare a liquid having a concentration of 0.5 w / v%, the viscosity of the liquid within 24 hours is 1500 mPa·s or less.

10. A filler for shield construction according to any one of claims 1 to 9, having damping properties that reduce vibrations and / or noise generated by shield construction.

11. A shield tunneling method comprising a filling step of filling the filler for shield tunneling according to claim 10 between a shield machine and the natural ground.

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