JP5930918B2 - Filling void filling material and filling method - Google Patents

Description

The present invention relates to a filling material and a filling method for embankment gaps used for embankment improvement in various embankment works, in particular, ground improvement work using a gap or the like generated in tunnel construction.

  Conventionally, an injection method using cement to reinforce and repair the embankment part, in order to reinforce the ground and to obtain a water-stopping effect, an injection material containing fine powder slag as a main component, and an emergency containing cement and calcium aluminate, etc. An injection material using a hard material is used (see Patent Documents 1, 2, 3, and 4).

  However, the infused material using fine powder slag has a very slow setting, and the infused milk may overflow from the embankment, be poured into groundwater, or may flow away from a predetermined pouring position.

The injection material using calcium aluminate is a mixture of cement milk and quick hard material slurry, which are mixed immediately before injection, so two mixers and pumps are required, and two types (1.5 shots, There is a problem that workability is complicated because of the two-shot method. When cement and a rapid hardening material are mixed and kneaded at the same time in order to simplify the workability, it is difficult to control the setting time, and there may be a problem that the mixer and the pump are hardened.
In addition, when the ground is a gap during tunnel excavation, the permeability of the filler is large, so the deviation of the filler to the embankment area is large, roads and rivers are polluted, and many times the prescribed amount of injection is required There was a case.

  In addition, the amount of water may be reduced at the time of injection in order to prevent deviation from the ground, but as a result, there is a risk of hardening too quickly, causing problems such as solidifying the mixer and pump, and the unit water volume The amount of unit cement increased due to the decrease, which was not economical.

JP-A-6-33057 Japanese Patent Publication No.57-10058 Japanese Patent Application Laid-Open No. 2004-149685 JP 2006-016543 A

  As a result of various investigations to solve the above-mentioned problems, the present invention has found that the use of a specific filler enables filling of a conventionally-filled embankment part. The present invention has been completed upon obtaining the knowledge that injection by a shot method is possible.

That is, the present invention comprises (1) cement, bentonite having a swelling degree of 5 to 40 , calcium aluminate, gypsum, a setting modifier, and water, and the fluidity from the time of kneading to 30 minutes is P. A filling material for embankment voids of a one-shot system having a funnel value of 9 to 12 seconds and a curing time of 40 to 90 minutes, (2) a setting regulator contains organic acids and alkali metal carbonates (1 ) Filling void filling material, (3) Bentonite is 25 to 10 parts by mass with respect to 75 to 90 parts by mass of cement (1) or (2) Filling void filling material, and (4) gypsum However, the filler for embankment voids according to any one of (1) to (3), which is 50 to 200 parts by mass with respect to 100 parts by mass of calcium aluminate, (5) 90 to 97 parts by mass of the total amount of cement and bentonite Against calcium alumina The filler for embankment voids according to any one of (1) to (4), wherein the total amount of gypsum is 10 to 3 parts by mass, (6) cement, bentonite, calcium aluminate, gypsum into the voids of the embankment When filling the filling material for embankment voids of any one of (1) to (6) containing a coagulation adjusting agent and water by the one-shot method, the fluidity from kneading to 30 minutes is P. It is a filling method of the embankment void portion having a funnel value of 9 to 12 seconds and a curing time of 40 to 90 minutes.

  By using the filling material for embankment voids according to the present invention, an effect is obtained that it is possible to fill the embedding part with a one-shot method.

Hereinafter, the present invention will be described in detail.
The parts and% used in the present invention are based on mass unless otherwise specified.

  As the cement used in the present invention, various portland cements such as normal, early strong and moderate heat, various mixed cements obtained by mixing blast furnace slag or fly ash with these portland cements, and various commercially available fine particle cements And eco-cement. Among these, it is preferable to use ordinary Portland cement in terms of economy and workability and low slump loss.

The bentonite used in the present invention is, for example, a kind of montmorillonite clay mineral having swelling properties. The swelling property of bentonite varies depending on the production area and the ore deposit, but the degree of swelling according to the ACC method (American colloid Company standard) is 5 or more, and the larger the degree of swelling, the more usually 10 or more, preferably 15 to 15 About 40 is more preferable. When the degree of swelling is less than 5, a predetermined P funnel value cannot be obtained, and it may be difficult to obtain the effect of preventing deviation to the embankment area.

The amount of bentonite used is such that the ratio of cement to bentonite is 75 to 90 parts of cement: 25 to 10 parts of bentonite. If the amount of bentonite used exceeds 25 parts, the filling of the embankment part will be poor, and if it is less than 10 parts, the fluidity will increase and it may be difficult to obtain the effect of preventing deviation to the periphery of the embankment part.

The calcium aluminate (hereinafter referred to as CA) used in the present invention contains CaO, Al ₂ O ₃ , and SiO ₂ , and contributes mainly to the expression of short-term strength when used in combination with gypsum.
The composition of CA is preferably CaO content 20 to 60%, Al ₂ O ₃ content 20 to 70%, CaO content 30 to 55%, Al ₂ O ₃ content 30 to 60%, and SiO ₂ content. 0 to 20% is more preferable. Outside this range, the short-term strength may be small.
CA is blended with calcia raw materials such as limestone, alumina raw materials such as alumina, bauxite, feldspar, and clay, and further silica raw materials such as quartzite, silica sand, quartz, and diatomaceous earth, and then rotary kilns, etc. It is manufactured by firing with or melting in an electric furnace or a high-frequency furnace.
The CA, the _{12CaO · 7Al 2 O 3, CaO} · Al 2 O 3, 3CaO · Al 2 O 3, 2CaO · Al 2 O 3 · SiO 2 and crystalline compounds such as _{CaO · Al 2 O 3 · 2SiO} 2 Although it can be used, a vitreous material obtained by quenching the melt is preferred from the viewpoint of high short-term strength.
The vitrification rate of CA is as follows: CA is heated at 1,400 ° C. for 2 hours, then slowly cooled at a cooling rate of 5 ° C./min, and the area S ₀ of the main peak of the crystalline mineral is determined by powder X-ray diffraction method. From the main peak S of the crystal, X (%) = 100 × (1−S / S ₀ ), 50% or more is preferable from the viewpoint of short-term strength, 80% or more is more preferable, and 90% or more Is most preferred. If it is less than 50%, the short-term strength may be small.
The fineness of CA is 3000 cm ² / g or more in terms of Blaine specific surface area, preferably 4000 to 7000 m ² / g, and less than 3000 cm ² / g, which is not preferable because the initial strength development is not sufficiently improved.

Examples of the gypsum used in the present invention include anhydrous gypsum, hemihydrate gypsum, and dihydrate gypsum, and natural gypsum, phosphate gypsum, waste gypsum, and chemical gypsum such as hydrofluoric acid gypsum, or Gypsum obtained by heat treatment is included. Of these, anhydrous gypsum is preferred because of its high strength development.
Fineness of gypsum to be used, 3000 cm ² / g or more in Blaine specific surface area, preferably 4000~7000cm ² / g, is less than 3000 cm ² / g, since not exhibit sufficient improvement in initial strength development is not preferable.
The amount of CA and gypsum used is preferably 50 to 200 parts, more preferably 70 to 150 parts with respect to 100 parts of CA. If the amount is less than 50 parts, the short-term strength is small, especially when the strength is poor at low temperatures, and if it exceeds 200 parts, the short-term strength may be small.

  The blending ratio of the total amount of cement and bentonite and the total amount of CA and gypsum (hereinafter referred to as “quick hardwood”) is 10 to 3 parts of quick hardener with respect to the total of 90 to 97 parts of cement and bentonite. 8 to 4 parts of the hardened material is more preferable with respect to 92 to 96 parts of the total bentonite. If the hardened material exceeds 10 parts, the time from the start of hardening to hardening may be too short, and the filling property may deteriorate, and if the hardened material is less than 3 parts, it may cause initial hardening failure. There is a case.

In the present invention, a setting modifier is used so that a required curing time can be obtained.
Examples of the setting modifier include organic acids and alkali metal carbonates. In these, it is preferable to use together organic acids and alkali metal carbonates from the point which can control hardening time, there is no obstruction | occlusion of a hose etc., and the strength development property after hardening is favorable.

Examples of the organic acids include oxycarboxylic acids such as citric acid, tartaric acid, malic acid, and gluconic acid, or salts thereof (sodium salt, potassium salt, etc.). Among these, oxycarboxylic acid and / or a salt thereof are preferable, and sodium citrate is more preferable in that the curing time can be controlled and there is no blockage of a hose or the like.

Examples of alkali metal carbonates include carbonates such as lithium carbonate, sodium carbonate, and potassium carbonate, and bicarbonates such as sodium bicarbonate and potassium bicarbonate. Among these, alkali metal carbonates are preferable and potassium carbonate is more preferable in terms of good strength development after curing.

When the organic acid and the alkali metal carbonate are used in combination, the mixing ratio of the two is preferably 5 to 200 parts, more preferably 10 to 100 parts, with respect to 100 parts of the alkali metal carbonate. If it is less than 5 parts, the curing time cannot be controlled and there is a possibility that a hose or the like may be blocked, and if it exceeds 200 parts, the initial strength development may be reduced.

  The amount of the setting modifier is not particularly limited because it is adjusted according to the temperature and the kneading time, but is preferably 0.1 to 3 parts with respect to 100 parts in total of cement, bentonite, and rapid hardening material. 0.3 to 2 parts is more preferable. If it is less than 0.1 part, it may be difficult to secure the kneading time, and if it exceeds 3 parts, the curing time may become abnormally long, resulting in a non-uniform solidified state. In the present invention, the curing time is preferably 40 to 90 minutes.

  The amount of water used in the preparation of the filler can be filled into the embankment part, and the flowability from the time of kneading to the effect of preventing deviation to the periphery of the embankment part is 30 minutes from the P funnel. The value is 9 to 12 seconds. In the production method, the amount of water is preferably 80 to 150 parts, more preferably 90 to 125 parts with respect to 100 parts of the filler. If less than 80 parts, the viscosity of the filler is high and the P funnel value is 12 seconds or more, and the fillability may be reduced. If it exceeds 150 parts, the fluidity is high and the P funnel value is 9 seconds or less. May cause deviation.

  The mixing method and filling method of the filler are not particularly limited, but the mixing method is preferably a high-speed mixer such as a hand mixer or a grout mixer, and the filling method is a one-shot method from the top of the embankment part. It can be applied to currently used methods such as pouring or filling the embankment with a single pipe.

  Hereinafter, the present invention will be described in detail by experimental examples.

Experimental example 1
80 parts of cement, 15 parts of bentonite, 5 parts of rapid hardening material consisting of 2.5 parts of CA and 2.5 parts of gypsum, and 0.7 part of a setting adjuster were mixed to prepare a filler having the amount of water shown in Table 1.
After producing the filler, the filling rate was measured using a simulated coarse aggregate layer in the test mold. The results are shown in Table 1.

<Materials used>
Cement: Ordinary Portland cement Bentonite: Swelling degree 20 by manufacturer's nominal ACC method, 200% mesh pass 90%
CA: Composition of CaO 45%, Al ₂ O ₃ 40%, and SiO ₂ 15% Gypsum: Anhydrous gypsum coagulant regulator: Mixture consisting of 100 parts of citric acid and 300 parts of potassium carbonate Water: Tap water

<Device used>
Test form: A rectangular form with a cross-section of 200 mm x 200 mm and a height of 800 mm (the bottom has a total of 25 round holes with a diameter of 20 mm and 5 vertical and horizontal openings), and a crushed stone of 5 to 25 mm The embankment mixed with an equal amount of crushed stone of 25 to 40 mm was filled so as to have a porosity of 38%.
Embankment (aka debris): The debris and rock debris excavated by tunnel excavation is usually about 5 to 40 mm, and this is simulated.

<Measurement method>
Curing time: The time when the temperature rose by 1 ° C. from the kneading by measuring the temperature of the filler was taken as the curing time.
P funnel value: Based on JSCE-F 521 “Method with P funnel”, the fluidity was evaluated after 30 minutes from kneading.
Fillability test: 12 liters (corresponding to a porosity of 38%) of filler is poured from the upper part into the mold filled with the aggregate, the amount of filler remaining in the upper part without filling, and the filling that flows out from the lower part From the amount of the material, the amount remaining in the mold (filling rate) was measured.

  From the results of Table 1, the filling rate within the range of the P funnel value is good, but the filler with a high P funnel value with a low water ratio is not filled in the lower part, and the P funnel value with a high water ratio is low. , The filler does not stay in the aggregate, and there is a large amount of leakage from the bottom hole.

Experimental example 2
A filler was prepared and tested in the same manner as in Experimental Example 1 except that the ratio of cement and bentonite shown in Table 2 was changed and the amount of water was kept constant at 100 parts. The results are shown in Table 2.

From Table 2, it was found that when the mixing ratio of cement and bentonite is an appropriate amount, high filling properties can be obtained.

Experimental example 3
Except for using 100 parts of CA and 100 parts of gypsum, and using the parts shown in Table 3 in a total of 100 parts of cement, bentonite, and hard material, the same as in Experimental Example 1 A filler was made and tested. The results are shown in Table 3.

From Table 3, it was found that a high filling property can be obtained when an appropriate amount of the hardened material is used. Moreover, since the gelation time of the one material state of a filler can be ensured, it can have a fixed working time and it turns out that it hardens | cures rapidly after filling.

Experimental Example 4
A filler was prepared and tested in the same manner as in Experimental Example 1 except that the setting modifier shown in Table 4 was used for a total of 100 parts of cement, bentonite, and rapid hardening material, and the filler was prepared. . The results are shown in Table 4.

From Table 4, it was found that when the setting modifier is in an appropriate amount, a high filling property can be obtained. It has been found that the gelation time of the single material state of the filler can be secured, so that it can have a certain working time and is cured quickly after filling.

Experimental Example 5
Except for changing the degree of swelling of bentonite, a filler was prepared in the same manner as in Experimental Example 1, and the test was performed. The results are shown in Table 5.

  From the results in Table 5, the filling rate within the range of the P funnel value is good, but the filler having a high degree of swelling and a high P funnel value is not filled in the lower part, and the degree of swelling is low and the P funnel value is low. , The filler does not stay in the aggregate, and there is a large amount of leakage from the bottom hole. It was found that when the degree of swelling is appropriate, high filling properties can be obtained.

  By using the filling material of the present invention for filling the embankment portion, the filling property is good, the deviation of the filling material from the embankment portion can be extremely reduced, and filling by a one-shot method is possible. Even when the gelation time in one material state of the filler is ensured, it is cured quickly after filling, and high strength development is obtained.

When this filler is used as the ground filling material used in the embankment of ground improvement work in various civil engineering works, it takes sufficient construction time and has excellent filling properties, so the filling property is improved and the conventional porosity is increased. It becomes possible to fill the geological ground that was difficult to adapt due to excessive or deviation. Curing after filling is quick, moving the filling point is quick, and workability is greatly improved.

Claims (6)

It contains cement, bentonite with a degree of swelling of 5 to 40 , calcium aluminate, gypsum, setting modifier, and water, and the fluidity from the time of kneading to 30 minutes is 9 to 12 seconds at the P funnel value, setting. A filling material for embankment voids of a one-shot method, characterized in that the time is 40 to 90 minutes. The filler for embankment voids according to claim 1, wherein the setting modifier contains an organic acid and an alkali metal carbonate. The filling material for embankment voids according to claim 1 or 2, wherein the bentonite is 25 to 10 parts by mass with respect to 75 to 90 parts by mass of cement. The filler for embankment voids according to any one of claims 1 to 3, wherein the gypsum is 50 to 200 parts by mass with respect to 100 parts by mass of calcium aluminate. The filler for embankment voids according to any one of claims 1 to 4, wherein the total amount of calcium aluminate and gypsum is 10 to 3 parts by mass with respect to 90 to 97 parts by mass of the total amount of cement and bentonite. . One shot of the filler for the embankment void portion according to any one of claims 1 to 5, comprising cement, bentonite, calcium aluminate, gypsum, a setting regulator, and water in the void portion of the embankment portion. A filling method for filling voids, characterized in that when filling by a method, the fluidity from kneading to 30 minutes is 9 to 12 seconds in P funnel value and the curing time is 40 to 90 minutes.