KR100938884B1 - Accelerating mortar for grouting underground cavity by using a eco-friendly cement mineral kingdom and grouting method using this - Google Patents

Abstract

PURPOSE: A flash setting mortar for grouting underground cavity using environmentally-friendly cement mineral is provided to shorten gel time of the flash setting mortar inserted to the underground cavity. CONSTITUTION: A flash setting mortar for grouting underground cavity using environmentally-friendly cement mineral contains a first material and second material. The first material contains 30-70 wt% of calcium aluminate(CaO-Al2O3), 20-50 wt% of calcium sulfoaluminate(CaO-Al2O3-SO3), 2-25 wt% of silicon dioxide powder, 0.01-0.2 wt% of hardening regulator, 0.01-2.0 wt% of fluidifier, and 0.01-0.5 wt% of anti-foaming agent. The second material contains 80-95 wt% of ordinary Portland cement(OPC), 1-10 wt% of gypsum, 1-15 wt% of calcium hydroxide, hardening regulator, and 0.01-2.0 wt% of fluidifier.

Description

Fastening mortar for grouting underground cavity using eco-friendly cement minerals and grouting method using the same {ACCELERATING MORTAR FOR GROUTING UNDERGROUND CAVITY BY USING A ECO-FRIENDLY CEMENT MINERAL KINGDOM AND GROUTING METHOD USING THIS}

The present invention relates to a rapid mortar for grouting underground cavities such as abandoned mines, and more particularly, even if underground cavities such as abandoned mines are made of a steep slope, the mortar is cured at a desired position while flowing along the slope of the cavity, The present invention relates to a rapid mortar for grouting underground cavity using environmentally friendly cement-based minerals that harden mortar without decomposition even if groundwater exists in the groundwater, and a grouting method using the same.

In general, mine tunnels are temporarily operated until the mining work is completed. Unlike civil engineering tunnels and large underground spaces, which are permanently operated, they do not have sufficient reinforcement and blasting type is completely excluded from blast vibration control. Due to the exaggerated blasting, rocks and main walls around the tunnel are damaged by blasting vibrations, and cracks are developed and relaxation areas are spread around the cavity. As a result, there is a high risk of ground subsidence.

Subsidence due to abandoned mine can be divided into Trough type sink and sinkhole type sink.

Trough-type settlements produce a sequential surface subsidence curve over a large area, and over long periods of time they are not well recognized. This settlement is caused by the destruction or punching phenomenon of Gwangju, which was supporting the upper half, and is caused by a gentle slope, and gradually occurs over a long period of time, affecting the stability of the upper structure.

On the other hand, since sinking occurs because the sinking type sinks in the form of depressions, the sinking amount is large and difficult to predict. In addition, the settlement is in the form of a steep cylindrical or conical shape, with settlements ranging from a few meters to several tens of meters, and transferred by the bulking of rocks due to the collapse of the upper part of the mining cavity and the decrease in strength due to the inflow of groundwater. It is a form of settlement that is small in size but can cause serious damage to life and ground structures.

Mining cavity, which acts as the biggest cause of settlement, affects settlement according to its size, shape and depth, and also affects settlement according to the condition of the upper half of the drilling cavity.

The size, shape, and depth of the mining cavity depend on the mining method and the degree of mining, and the interaction with the mining surrounding ground conditions also greatly affects the settlement.

Particularly, in Korea, the collapsed mining method has been used in the past.

On the other hand, it is very difficult to predict when the sinking occurs because it is determined by various factors such as the strength, fracture range, groundwater presence, cavity depth, mining scale, etc.

Therefore, the joint reinforcement method for the areas of ground subsidence should be reviewed and applied economically, constructively, jointly, and on the surface of the area where structures and lives are expected to be greatly affected by future settlement.

In order to prevent ground subsidence damage caused by underground mining cavities, review the suitability and applicability of the construction method and select the reinforcement method considering the mining status and ground conditions of the target area.

Methods that can be applied to prevent ground subsidence include cavity top reinforcement, joint construction in the cavity, grout column, grout case, hydraulic filling, filling grout, full excavation and refilling.

Since the present invention relates to a filling grout, only the filling grout will be described below.

In the mining grouting, the grouting range is wide, so it is economical to fill the required section, and it needs sufficient durability with full filling effect. Also, it does not cause the deterioration of durability in the long term. A material that does not generate this is required.

In general, cement mortar or the like is used to fill the mining area.

If the slope of the mining slope is gentle, it can be effectively filled by shortening the mortar's setting time to some extent.However, in the case of the steep slope, the slope of the mine is completely filled because the mortar flows downward to the bottom of the mine due to the flow of mortar. There is a problem that takes a large amount of mortar until.

In case of using the water glass-based fastener (chemical liquid), the quickening performance is given, but the hardening shrinkage of the hardened body is very long-term after curing, and the strength is weak, and the leaching phenomenon of the unhydrated part in the groundwater is released. This occurs and causes a problem of deterioration in the long term. This can be explained by the fact that in the long term, the unreacted cement particles are dissolved because the cement particles are not sufficiently reacted and there are many remaining parts, and the water glass is in an excessive state. . Also, in the dry or ground where moisture is absorbed rapidly, the soft gelled material shrinks as the water of the gelled water glass evaporates or escapes rapidly. Will be.

The present invention is to solve the above problems, even if the underground cavity is inclined, such as abandoned mines, mortar is cured during the flow on the inclined surface to form a stack of hardened layer, which acts as a dam, the steep slope mining area is filled with the minimum material The purpose of the present invention is to provide a rapid mortar for grouting underground cavity using environmentally friendly cement mineral and a grouting method using the same.

In addition, another object of the present invention is to ensure that even in the situation where the groundwater is filled in the mining traces, mortar is not decomposed and a normal hardened body is formed, and a deterioration of durability does not occur in the long term and prevents secondary environmental pollution due to long-term leaching. have.

In order to achieve the object as described above, the rapid mortar for grouting underground cavity using environmentally friendly cement-based minerals according to the present invention is calcium aluminate (CaO-Al ₂ O ₃ ), calcium sulfoaluminate (CaO-Al ₂ O ₃ -SO ₃ ), milk powder (A) is mixed with water to the first material consisting of stone powder, hardening control agent, fluidizing agent, water insoluble agent, antifoaming agent;

General portland cement (OPC), gypsum, slaked lime, hardening control agent, fluidizing agent, mortar material (B) is mixed with the aggregate and water is characterized in that the mixture is made of water.

According to the rapid mortar for grouting underground cavity using environmentally friendly cement minerals and the grouting method using the same according to the present invention, the gel time of the rapid mortar injected into underground cavity such as underground mining area is drastically shortened than before. Even if the slope of the part is abrupt, the rapid mortar does not flow down the underground cavity but hardens at the desired location and acts as a dam so that grouting can be done where it is needed by using a small amount. It can shorten the air.

In addition, even if the initial and long-term high compressive strength is expressed and the groundwater is present in the underground cavity, the rapid freezing mortar is not separated by the groundwater and is rapidly frozen, thereby reducing the air and the city park.

The rapid mortar for grouting underground cavities using eco-friendly cement minerals according to the present invention is composed of a milk material and a mortar material.

The milk material includes a calcium aluminate (CaO-Al ₂ O ₃ ) -based mineral, calcium sulfoaluminate (CaO-Al ₂ O ₃ -SO ₃ ) -based minerals as a component, the mortar material is a general port And a second material composed of lant cement (OPC), slaked lime (Ca (OH) 2) and anhydrous gypsum (CaSO 4).

Each of the first material and the second material includes a cellulose-based thickener, a fluidizing agent, a condensation delaying agent, and a curing accelerator for achieving the purpose.

Quick mortars of this composition can be injected into underground cavities, for example, by means of 1.5 or 2.0 shot grouting equipment.

The rapid mortar according to the present invention allows the mortar to harden during the construction of the mining filling grouting to be cured during the flow of the inclined surface to form a stack of hardened layers, which serve as a dam, so that the steep mortar can be filled with a minimum amount of solidification time. It is possible to shorten the quenching performance, to prevent the mortar from being decomposed and to form a normal hardened body even when the groundwater is filled inside the mining track, and to prevent the environmental pollution of the leachate discharged by contact with rainfall or groundwater after grouting. Harmlessness, and these characteristics are demonstrated by the following detailed description.

Milk material and mortar material constituting the quench mortar is used by mixing 30 to 60% by volume milk material, 40 to 70% by volume mortar material.

The first material is calcium aluminate (CaO-Al ₂ O ₃ ) 30 ~ 70wt%, calcium sulfo aluminate (CaO-Al ₂ O ₃ -SO ₃ ) 20 ~ 50wt%, stone powder 2 ~ 25wt%, hardening regulator 0.01 ~ 2.0 wt%, fluidizing agent 0.01 ~ 2.0wt%, underwater disintegrating agent 0.01 ~ 2.0wt%, defoamer 0.01 ~ 0.5wt% is made of a mixture.

The first material is mixed with water to be used as a suspension, and the mixing ratio (wt%) of the first material and water is 100: 80 to 100. The milk material is a mixture of the first material and water.

The calcium aluminate (CaO-Al ₂ O ₃ ) component is an amorphous C ₁₂ A which is the mineral that reacts most rapidly with general Portland cement among the calcium aluminate minerals CA, C ₃ A, C ₁₂ A _{7, and} CA ₂ . ₇ (CaO: Al ₂ O ₃ molar ratio of 12: 7) The mineral was used as a material, the C ₁₂ A ₇ mineral is characterized by a very fast hydration reaction.

Amorphous means that it melts by applying heat and then rapidly cools before the crystal array is ready, and each member is solidified to a state where it cannot find the arrangement position (liquid state). It is like a liquid and mixed with general portland cement. hydration of Ca ⁺⁺ ions and is in the state SO ₃ ^- in combination with the ion-eth- Lin ZUID ^{(... Ettringite, 3CaO Al} 2 O 3 3CaSO 4 32H 2 O) there is generated the case of the amorphous crystal C Due to the relatively slow rate of ₁₂ A ₇ melting, ethrinzite is not produced at the surface of the C ₁₂ A ₇ particles, but rather within a slightly spaced gap, so that the hydrate does not cover the C ₁₂ A ₇ particles, thus C ₁₂ A ₇ Particles are melted normally and continuously react to fill the gaps between particles to bond the particles, which causes a sudden occurrence. When the content is less than 30wt%, the quickening force decreases, and the fastening performance is too fast at 70wt% or more, which makes it difficult to control the reaction rate, which causes a difficulty in construction work.

The calcium sulfo aluminate (CaO-Al ₂ O ₃ -SO ₃ ; CSA) is a C ₄ A ₃ S is used as a main compound material having a specific surface area of 4,500 ~ 8,000 (㎠ / g) for the initial reactivity, If the content is 20wt% or less, the gel time is delayed and the compressive strength is lowered. If it is 50wt% or more, the gel time is too fast, causing workability deterioration.
Calcium aluminate (CaO-Al ₂ O ₃ ) minerals and calcium sulfoaluminate (CaO-Al ₂ O ₃ -SO ₃ ) minerals, which are cement-based minerals used in the present invention, are stable in the long term by forming a complete hydration hardener It is eco-friendly because it is a cement-based material that does not cause environmental pollution such as groundwater pollution.

The lime powder is a powder material of -170mesh in the pulverized fine powder or mixture of limestone, dolomite, and silica, and it is for maintaining the compressive strength. In 2wt% or less, material separation is likely to occur in the slurry of the first material and 25wt%. In the above, it becomes a factor that causes difficulty in application of construction equipment due to the increase in viscosity of slurry.

The hardening control agent is for controlling the curing time of the rapid mortar and is made by mixing a retarder composed of citric acid, sodium citrate, tartaric acid borate or a mixture thereof, and an accelerator consisting of sodium carbonate, lithium carbonate or a mixture thereof, 0.01wt% In the following, the curing effect is insignificant and there is no significant difference in the curing effect at 2.0 wt% or more. The retarder and the accelerator may be mixed in the same ratio.

The fluidizing agent is to ensure the fluidity of the composition is made of melamine-based, polycarboxylic acid-based or mixtures thereof, it is difficult to secure the fluidity required for the construction work at 0.01wt% or less, the material when kneading the composition at 2.0wt% or more Separation is a cause of difficulty in smooth operation.

The water-insoluble agent is used to prevent dispersion occurring during grouting of the mortar in water, using a cellulose-based organic thickener. In 0.01 wt% or less, the dispersion of the mortar in the water is too severe. Grouting is difficult due to the increase in viscosity, which causes difficulty.

The antifoaming agent is a powder antifoaming agent for removing bubbles generated during kneading of the first material, and bubbles are not properly removed at 0.01 wt% or less, and hardening time is affected at 0.5 wt% or more, causing deterioration of fastening force. do.

The second material is 80 ~ 95wt% of general portland cement (OPC), 1 ~ 10wt% of gypsum, 1 ~ 15wt% of slaked lime, 0.01 ~ 2.0wt% of hardening control agent, 0.01 ~ 2.0wt% of fluidizing agent, 0.01 ~ 2.0 of water inseparable agent wt% is mixed.

The second material is mixed with sand and water to be used as mortar, and the mixing ratio (wt%) is 100: 100: 60-80. The mixture of the second material, sand and water is called a mortar material.

The gypsum uses anhydrous gypsum among the types of gypsum divided into dihydrate gypsum, hemihydrate gypsum and anhydrous gypsum, and serves to shorten the curing time and improve the compressive strength. It has a weak role in enhancement and results in lowering the compressive strength rather than 10 wt%.

The slaked lime is to shorten the hardening time to further improve the fastening performance. Less than 1.0wt% has a role of shortening the hardening time, and at 15wt% or more, the compressive strength is lowered as compared to the effect of shortening the hardening time. Cause.

Since the hardening regulator, the fluidizing agent, and the water-insoluble agent used in the second material are the same as those described in the first material, the detailed description is omitted.

Hereinafter, an embodiment of a ground mortar for grouting underground cavity using environmentally friendly cement-based minerals according to the present invention will be described.

<Example 1>

1. Material

end. Calcium aluminate (C ₁₂ A ₇ , Amorphous): Powder level (Bleinch) 5,000 cm 2 / g or more,

I. Calcium sulfoaluminate (CSA): 5,500 cm 2 / g or more (blein)

All. Lime powder: Limestone fine powder (-170mesh powder)

la. Cement: ordinary portland cement,

hemp. Slaked lime: Ca (OH) ₂ 90% or more,

bar. Gypsum: Anhydrous gypsum, powder degree (Bleinch) 4,500㎠ / g or more,

four. Curing Control Agents: Retardant: Sodium Citrate

                      Promoter: Sodium Carbonate

Ah. Glidant: Polycarboxylic acid powder type glidant

character. Water-insoluble agent: Methyle Cellulose thickener

car. Antifoam: Powder Antifoam

2. Material Mixing Ratio

end. Milk material compounding ratio

I. Mortar material compounding ratio

3. Physical performance measurement result

When kneading the milk material, the kneading water ratio was changed to 80 to 100 weight ratio, and the physical performance was measured and the mortar material composition was tested as fixed in the table (2-b. Mortar material mixing ratio). The mixing ratio of ash was 1: 1 in volume ratio.

As can be seen from the physical performance measurement result table, the kneaded water ratio is less than 80 weight ratio, it is determined that there is a difficulty in construction due to the high slurry viscosity, and when the weight ratio exceeds 100 weight ratio, gel time and setting time delay are appeared and It was confirmed that the deterioration phenomenon of the rapid mortar in water dropped.

<Example 2>

1. Material and characteristic experiment

The mixing ratio of the milk material was the same as in Example 1, the kneaded water (water) was fixed at 100 weight ratio, the ratio of kneaded water (water) in the mortar material mixing ratio of Example 1 60 to 80 weight ratio (based on the second material) The change in physical properties was measured. At this time, the mixing ratio of the milk material and the mortar material was 1: 1 in volume ratio as in Example 1.

2. Physical performance measurement result

When the kneaded water ratio is less than 60 wt%, it is judged that the construction is difficult due to the high viscosity of the slurry, and when it exceeds 80 wt%, it is confirmed that material separation occurs. The gel time was found to be delayed.

<Example 3>

In order to analyze the environmental impact of the quench mortar according to the present invention was analyzed by the following heavy metal dissolution test conditions and the mixing ratio for preparing the specimen is the same as in Example 1, wherein the kneaded water (water) ratio of the milk material is 100% by weight .

1. Heavy Metal Dissolution Test Conditions

2. Heavy Metal Dissolution Test Results

Analysis item unit Analysis Hg Mg / l Not detected CD 〃 〃 As 〃 〃 Cr6 + 〃 〃 Pb 〃 〃

<Comparative Example>

In order to confirm the properties of the quench mortar according to the present invention, the physical performance was compared with the conventional water glass chemical injection material. The mixing ratio of the rapid mortar was the same as in Example 1, the kneaded water (water) ratio of the milk material was 100 weight ratio, and the mixing ratio of the milk material and the mortar material was 1: 1 in volume ratio.

Conventionally, the water glass system is a liquid phase, and the molar ratio of Na ₂ O: SiO ₂ is 1.4.

1. Water Glass Injection Material Mixing Ratio

2. Comparison of the present invention and conventional physical performance

As can be seen from the physical performance comparison table, the present invention shows that the gel time is faster than that of the conventional water glass-based injection material and that the compressive strength is always large regardless of age.

The grouting method using the rapid mortar for grouting underground cavity using environmentally friendly cement-based minerals is as follows.

(S10) Material Preparation.

The first material and water are mixed in a predetermined ratio to prepare a milk material, and the second material, aggregate and water are mixed in a predetermined ratio to prepare a mortar material.

By preparing the mortar according to the present invention by mixing the milk material and the mortar material prepared in each process.

(S20) Grouting position selection.

Investigate underground cavities such as abandoned mines, and select areas that need reinforcement. Since the location selection is the same as the existing method, detailed description is omitted.

(S30) Grouting.

The injection nozzle of the 1.5 to 2.0 shot grouting equipment is inserted into the position selected in the step S20 to inject the present invention. The grouting area will be determined according to the condition of the ground. The grouting area will be determined based on the grouting area.

Quick mortar hardens within a few to several tens of seconds from injection to block underground cavities and reinforce the ground.

Claims (3)

Calcium aluminate (CaO-Al ₂ O ₃ ) 30 ~ 70wt%, Calcium sulfoaluminate (CaO-Al ₂ O ₃ -SO ₃ ) 20 ~ 50wt%, Stone powder 2 ~ 25wt%, Hardening regulator 0.01 ~ 2.0wt%, A milk material (A) in which 80 to 100 weight ratio of water is mixed with respect to 100 weight ratio of the first material consisting of 0.01 to 2.0 wt% of a fluidizing agent, 0.01 to 2.0 wt% of a water inseparable agent, and 0.01 to 0.5 wt% of an antifoaming agent; General Portland Cement (OPC) 80 ~ 95wt%, Gypsum 1 ~ 10wt%, Slaked lime 1 ~ 15wt%, Hardening modifier 0.01 ~ 2.0wt%, Fluidizing agent 0.01 ~ 2.0wt%, Water disintegrating agent 0.01 ~ 2.0wt% Mortar material (B) in which 100 weight ratio of aggregates and 60 to 80 weight ratios of water are mixed with respect to 100 weight ratio of the second material; rapid mortar for grouting underground cavity grouting using environmentally friendly cement-based minerals. The method according to claim 1, The milk material and the mortar material is a rapid mortar for grouting underground cavity using environmentally friendly cement-based minerals, characterized in that 30 to 60% by volume, 40 to 70% by volume. Ground cavity grouting using environmentally friendly cement-based minerals, characterized in that the rapid mortar for grouting underground cavity using environmentally friendly cement minerals according to claim 1 or 2 is injected into the underground cavity using 1.5 to 2.0 shot grouting equipment. Grouting construction method using molten mortar.