KR20050022061A - ultra-high-strength urethane composition for solidifying weak foundation - Google Patents

Abstract

PURPOSE: Provided is a high strength urethane liquid composition for solidifying the weak ground used in the polyurethane injection technique of NATM (new Austrian tunneling method) which can maintain strength to be constant owing to a small effect of water even if the liquid composition is absorbed in the underground water during injection process. CONSTITUTION: The urethane liquid composition comprises a liquid A which comprises 65-85 wt% of a polyol containing a polyol having at least two hydroxyl groups and 10-15 wt% of an oil having a hydroxyl group capable of urethane reaction; and a liquid B which comprises an isocyanate compound containing an isocyanate group, in a ratio of 1:1 to 1:1.1 by weight. Preferably the polyol having at least two hydroxyl groups is at least one selected from a di- or more valent alcohol polymer such as a polyoxyalkylene diol, a polyoxyalkylene triol, glycerin, sorbitol, etc.; the oil having a hydroxyl group capable of urethane reaction is at least one selected from a camellia oil, an olive oil and a castor oil; and the isocyanate compound is a prepolymer obtained by reacting diphenylmethane diisocyanate and a polyol. Preferably the liquid A comprises further at least one catalyst selected from an organometallic catalyst and a tertiary amine-based catalyst.

Description

Ultra-high-strength urethane composition for solidifying weak foundation}

Under the current situation where the use of underground space is gradually expanding due to the development of the industrial society, tunnels are gradually built by NATM (New Austrian Tunnelling Method) among the temporary facilities of subways, electric power stations, communication districts and other underground spaces. It is increasing.

Fundamentally supporting the tunnel is the surrounding base, and to take advantage of the support function possessed by the surrounding base, always pay attention to the relationship between the ground reaction force and the strength generated by excavation. The generated stress is determined by the inherent properties of the ground, such as the initial stress of the ground, the side pressure coefficient, the cross-sectional shape of the tunnel, the excavation method, and the excavation method, and can be understood as the degree of stress concentration in the ground. If the support member is designed to secure stability during construction, it should be made for economic efficiency. If the support strength is less than the generated stress, the support member, cross-sectional shape and construction method should be thoroughly reviewed to reduce the strength and stress concentration of the support plate. As far as possible, design and construction should be prevented. NATM method is a method that supports the ground around tunnel and stabilizes the tunnel based on the theory of reverse mechanics. This method is mostly used for tunnel construction in domestic roads and is mainly used when the tunnel is curved, the excavation section is large, and the ground is poor.

When the tunnel is constructed by the NATM method, various auxiliary methods are introduced to reinforce the tunnel ground. Each method has its own characteristics and advantages and disadvantages.

In general, as a ground reinforcing assistance method of NATM, water glass-based and cement-based suspension types have been applied. In particular, the cement suspension method is commonly used for the purpose of enhancing the ground strength. The cement suspension method is low cost and guarantees a certain strength, but the hardening period is long, the order effect is inferior, and the load is large, causing problems during penetration, and the effect is hardly expected in soft ground such as clay or silt ground.

In such soft ground conditions, the steel pipe multi-stage injection method and the urethane-based chemical injection method are widely utilized.

Steel pipe multi-stage injection method has good effect of strength increase and load reduction, but it is inferior in order effect and it is very disadvantageous to fit air because process required for reinforcement has a great influence on excavation process. Almost unanticipated, the scope of application is very limited.

In addition, the LW-based chemical injection method and the SGR-based chemical injection method, which are widely used in recent years, have been developed based on the phenomenon that gel is formed when water glass chemical and cement suspension are mixed. Although it has the advantage of being inexpensive, there is a need for large-scale facilities, and other complex mechanical facilities such as boring machines must be installed in the drilling, and the groundwater effects on the freezing characteristics of the fluctuating ground such as fine sand or clay layers are intentionally limited. There is a disadvantage that construction is difficult.

The newly known polyurethane injection method (hereinafter referred to as urethane method) is a rock solidification method (PU-IF) that has been started since the 1990s.

In the urethane method, after drilling at regular intervals in soft strata, crushing zones and fault zones, insert injection bolts, and mix the two-component foamable urethane-based chemical solution in the inserted injection bolts to apply a pressure of about 1-20kg / ㎠ to develop joints. It is a method to prevent collapse and deformation by completely filling the rock pieces between the rocks to support the rock loading on the upper part of the tunnel by forming an arch shape.

In addition, it is possible to prevent the activity due to the side pressure of the side wall, and in particular, since the voids between the arm pieces are completely filled with urethane chemicals, a perfect ordering effect can be obtained.

The urethane injection liquid used in the conventional urethane method uses the two-component urethane chemical liquid which consists of A liquid which is a hardening | curing agent, and B liquid as a main body.

In the composition of the two-component urethane chemical solution, the liquid A is a polyether polyol and its derivatives, and the liquid B is a MDI (Diphenylmethane Diisocyanate) -based prepolymer and its derivatives.

In the case of A liquid used as a curing agent, a crosslinking agent, a foam stabilizer, a foaming aid, and a viscosity reducing agent have been added to the polyol compound.

In the case of the B liquid used as the subject, diphenylmethane diisocyanate and the like are included.

The reaction state is hydrogen-bonded to generate a three-dimensional strong urethane resin because the isocyanate group (liquid B) of the main prepolymer and the polyol hydroxyl group (liquid A) of the curing agent are mixed and stirred through a stationary mixer mounted in the injector.

Urethane reaction consists of a polymerization reaction, a hydrolysis reaction, a saturation reaction, and a crosslinking reaction.

Conventional urethane chemicals as injectors use a mixture of A and B in a ratio of 1: 2.8 ± 3, and have a separate pump, each of which is joined by mixing to the desired site through a stop mixer in the Y-shaped pipe located at the tip of the injector. It is used by injection.

Such conventional urethane chemicals generally have a compressive strength of about 450 N / cm 2 and a flexural strength of about 500 N / cm 2, which are weak in strength and thus have problems with complete ground reinforcement. In addition, when the groundwater and the chemical liquid is mixed in the order of order, the compressive strength is lowered to about 50 N / cm 2 or less and tends to be easily broken.

In addition, solvents such as ethyl acetate and methylene chloride, which are used as a viscosity lowering agent and a blowing agent mixed in the liquid A and the liquid B, have a lethal toxicity to the human respiratory system, worsening the working environment, and also destroying the environment around the work place. There is this.

In addition, since the mixing ratio of the liquid A and the liquid B was 1: 3, it was not physically easy to achieve complete mixing when mixing, and thus there were many problems in the physical properties after the reaction.

The present invention relates to a novel and advanced urethane liquid pharmaceutical composition that improves the disadvantages of the urethane chemical composition used in the polyurethane injection method, which is an auxiliary ground strengthening method of the NATM method.

One aspect of the present invention,

Soft ground solidifying urethane consisting of a liquid A containing a polyol comprising a primary polyol having two or more hydroxyl groups and an oil having a hydroxyl group capable of urethane reaction, and a B liquid containing an isocyanate compound containing an isocyanate group. It relates to a pharmaceutical composition.

The polyol having two or more hydroxyl groups contained in the solution A is selected from at least one of a dihydric alcohol polymer such as polyoxyalkylene diol, polyoxyalkylene triol, glycerin, sorbitol, or a trivalent or higher alcohol polymer. The content of the polyol in the liquid A is 60 to 85% by weight, preferably 65 to 85% by weight. Preferably, liquid A comprises 60 to 70% by weight of polyoxyalkylene diol, and 5 to 10% by weight of polyoxyalkylene triol.

The polyol preferably has a hydroxyl value of 100 or more. Specifically, the hydroxyl value of the polyoxyalkylene diol is preferably 450 or more, and the hydroxyl value of the polyoxyalkylene triol is preferably 100 or more.

The oil having a hydroxyl group capable of the urethane reaction is selected from camellia oil, olive oil, and castor oil as an undried oil having an iodine value of 100 or less, and castor oil is preferable. The content of oil in liquid A is 10 to 15 weight percent.

The liquid A includes a catalyst selected from at least one of an inorganic metal catalyst and a tertiary amine catalyst. The inorganic metal catalyst is preferably a tin-based catalyst or a lead-based catalyst as the main catalyst, and specifically, dibutyl tin dilaurate is preferable. The tertiary amine catalyst is preferably triethyl amine as a subcatalyst. The content of the catalyst in the liquid A is 0.5 to 5% by weight, preferably 0.5 to 1.0% by weight of dibutyl tin dilaurate and 2-3% by weight of triethyl amine.

The liquid A contains a silicon foam stabilizer. Silicone foam stabilizers are silicone foam stabilizers used in commercially available urethane rigid foams. The content of the foam stabilizer in the A liquid is preferably 1.0 to 1.5% by weight.

The liquid A may further include triethanol amine as a crosslinking agent. The content of the crosslinking agent is 2 to 5% by weight.

The liquid A may further include water as a blowing agent. The content of water is 1% by weight or less.

The isocyanate compound contained in the liquid B is preferably a prepolymer-reacted isocyanate compound, and specifically, a prepolymer in which a polyol is reacted with diphenylmethane diisocyanate (MDI) is preferable. The polyol used in the prepolymer reaction is selected from at least one of ethylene glycol, dipropylene glycol and polyoxyalkylene triols.

As a specific component of the said liquid B, 85-92 weight% of diphenylmethane diisocyanate and 8-15 weight% of polyols are preferable.

The liquid A and liquid B are used in combination in a weight ratio of 1: 1 to 1: 1.1.

[Injection method of drug solution according to the present invention]

In the urethane chemical composition according to the present invention, A and B liquids are mixed through the injector while passing through the fixed mixer at the injector tip of the Y-type pipe, and are discharged through the holes at the tip of the pipe (packer) installed by press-fitting, whereby the injection resin is It penetrates into the soft ground and achieves fast curing within 5 minutes.

The urethane chemical composition according to the present invention is mainly used for ground reinforcement of tunnel top end, filling construction of overhole and perforated rear surface by rock dropout, tunnel reinforcement and sidewall reinforcement and ground relaxation prevention, and history layer ordering effect.

The invention is illustrated in more detail by the following examples, but is not limited by the following examples.

Example 1

Preparation of liquid A

70% by weight of polyoxypropylene diol,

7% by weight of polyoxyalkylene triol,

15% by weight castor oil,

1.0% by weight of dibutyl tin dilaurate (main catalyst),

2% by weight triethylamine (cocatalyst),

4.5% by weight of triethanolamine (crosslinking agent)

0.5% by weight of water (foaming agent)

Production of liquid B

Difetyl methane 4-4 'diisocyanate (MDI) 87% by weight

Diethylene glycol 13% by weight

Comparative Example 1

A amount

40% by weight of polyether polyol

Diethylene glycol 38% by weight

Butanediol 10% by weight

5% by weight of triethanolamine

1% by weight of DMEA and TEDA

Ethylene Acetate 4% by weight

2% by weight of silicone foam stabilizer

B amount

MDI 92% by weight

Methylene chloride 8% by weight

The following is a comparison table for the resulting reinforcing material after the reaction of the urethane chemical solution (A liquid and B liquid) according to the present invention prepared in Example 1 and the urethane chemical liquid according to the prior art prepared in Example 1.

Viscosity is tested according to KS M 3705 (General Test Methods for Adhesives).

Specific gravity test is carried out in accordance with KS M 5000 (Testing methods for paints and related materials).

The flexural strength and compressive strength test is obtained by tensile strength at a speed of 2mm / min through a universal testing machine while foaming 4 times urethane with a thickness of 2.5 cm, a length of 8 cm, and a width of 5 cm on a steel sheet.

-Comparison Table-

Exam Content Configuration unit Example 1 Comparative Example 1 Viscosity (25 ± 1 ℃) A liquid mPa.s 100 60 B liquid mPa.s 94 60 Specific gravity (25 ± 1 ℃) A liquid 1.00 1.01 B liquid 1.23 1.23 Compressive strength Reactant N / cm2 1576 450 Flexural strength Reactant N / cm2 3490 510 Tensile Shear Adhesion Strength Reactant N / cm2 250 180 Compounding ratio 1: 1 1: 2.9

* Korea Chemical Testing Institute test of April 8, 2003

As can be seen in the above table, the urethane chemical according to the present invention can achieve perfect ground and rock reinforcement by maintaining super high strength of about 3000 N / cm 2 or more of compression strength, 1500 N / cm 2 or more of bending strength. In particular, even when the chemical is absorbed into the groundwater during the injection of the chemical solution, the influence of the water on the reaction product is less, so that the constant strength can be maintained.

In addition, by applying a prepolymer method without using conventional solvents such as methylene chloride, ethyl acetate, etc., it is environmentally friendly and harmless to the human body.

In addition, the chemical solution according to the present invention is a mixture ratio of the liquid A and liquid B is 1: 1 to 1: 1.1 can be physically completely blended to improve the work efficiency.

Claims (15)

A liquid comprising a polyol comprising a polyol having two or more hydroxyl groups and an oil having a hydroxyl group capable of urethane reaction; And B liquid containing the isocyanate compound containing an isocyanate group Soft ground freezing urethane chemical composition The polyol according to claim 1, wherein the polyol having two or more hydroxyl groups contained in the liquid A is at least one of a dihydric alcohol polymer such as polyoxyalkylene diol, polyoxyalkylene triol, glycerin, sorbitol, or a trivalent or higher alcohol polymer. Urethane pharmaceutical solution selected. The urethane pharmaceutical composition according to claim 1, wherein the content of polyol in solution A is 65 to 85% by weight. 4. The urethane pharmaceutical composition according to claim 3, wherein the liquid A comprises liquid 60 to 70 wt% of polyoxyalkylene diol, and 5 to 10 wt% of polyoxyalkylene triol. The urethane chemical composition according to claim 1, wherein the oil having a hydroxyl group capable of the urethane reaction is one or more selected from camellia oil, olive oil, and castor oil. The urethane chemical composition according to claim 5, wherein the oil having a hydroxyl group capable of the urethane reaction is castor oil. The urethane chemical composition according to claim 1, wherein the oil content in the liquid A is 10 to 15% by weight. The urethane chemical composition of claim 1, wherein the liquid A comprises a catalyst selected from at least one of an organometallic catalyst and a tertiary amine catalyst. 9. The urethane pharmaceutical composition according to claim 8, wherein the organometallic catalyst is dibutyl tin dilaurate. The urethane chemical composition according to claim 8, wherein the tertiary amine catalyst is triethyl amine. The urethane chemical composition according to claim 8, wherein the content of the catalyst in the liquid A is 0.5 to 1.0% by weight of dibutyl tin dilaurate and 2-3% by weight of triethyl amine. The urethane chemical composition according to claim 1, wherein the isocyanate compound contained in the liquid B is a prepolymer obtained by reacting diphenylmethane diisocyanate (MDI) with a polyol. The urethane pharmaceutical composition according to claim 12, wherein the polyol used in the prepolymer reaction is one or more selected from ethylene glycol, dipropylene glycol, and polyoxyalkylene triol. The urethane pharmaceutical composition according to claim 1, wherein the liquid B comprises 85 to 92% by weight of diphenylmethane diisocyanate, 5 to 15% by weight of diethylene glycol, and 4 to 10% by weight of polymeric diphenylmethane diisocyanate. The urethane chemical composition according to claim 1, wherein the content ratio of the liquid A and liquid B is 1: 1 to 1: 1 by weight.