KR20230072556A - Method for rapid repairment of railway slopes - Google Patents

Abstract

The present invention relates to a railway slope repair and reinforcement method.
The railway slope repair and reinforcement method according to the present invention includes (a) installing a cradle on the damaged railway slope (b) filling the gap between the upper sheet having permeability and the lower sheet coupled to the lower part of the upper sheet and the upper sheet and the lower sheet Installing a composite mat having a super-fast-hardening binder in powder form on a cradle (c) curing the super-fast-hardening binder by supplying water through the upper sheet of the composite mat; and (d) filling the space between the cradle and the composite mat with a low-flow filling material and curing the low-flow filling material, including 90 to 92% by weight of a filler including fly ash and steelmaking slag, and a calcium aluminate-based material. 85 to 90% by weight of cement, 3 to 5% of cement, and 8 to 10% by weight of a binder composed of 5 to 10% by weight of calcium sulfoaluminate-based material. It is characterized by being

Description

Railroad slope repair and reinforcement method {METHOD FOR RAPID REPAIRMENT OF RAILWAY SLOPES}

The present invention relates to a repair and reinforcement method for civil structures, and more particularly, to a method for urgently repairing and reinforcing a railroad embankment slope damaged due to torrential rain or the like.

The railroad is formed on the embankment roadbed, which is piled up with soil. Filled roadbeds can be damaged by torrential rains that bring a lot of rain in a short period of time. 1 shows a case of damage to the slope of the railway embankment roadbed. These damage cases occur steadily every year, as confirmed in the table below <2010-2020 slope damage status>, and especially in the case of frequent torrential rains and typhoons like in 2020, the number of damages also increases.

When a railroad slope collapses due to torrential rain, emergency restoration is requested.

However, there are several limitations to the emergency restoration of the railroad slope. First, there is a time constraint. Since the railways have to operate on a daily basis, restoration can only take place during times when trains are not in operation. If the damage is large enough to stop train operation, it must be restored quickly, but the method of re-filling the damaged part is not desirable because it takes a long time to construct. In addition, since railways are often separated from roads, restoration equipment also has difficulty in accessing through railways. In addition, since the railroad bed is formed as a slope, there is a problem in that there is not enough working space for recovery equipment to work.

Recently, studies have been conducted to restore the railroad slope using civil mats, but various problems in construction are appearing because the specificity of the railroad slope is not considered.

The present invention is to solve the above problems, and an object of the present invention is to provide a construction method that can very quickly and safely restore a damaged railroad embankment slope using a civil engineering composite mat.

Meanwhile, other unspecified objects of the present invention will be additionally considered within the scope that can be easily inferred from the following detailed description and effects thereof.

The railway slope repair and reinforcement method according to the present invention for achieving the above object includes: (a) installing a cradle on a damaged railway slope; (b) installing a composite mat having a water-permeable top sheet, a bottom sheet coupled to a lower portion of the top sheet, and a super-fast binder in a powder state filled between the top sheet and the bottom sheet on the cradle; (c) supplying water through the upper sheet of the composite mat to cure the super-fast binder; and (d) filling and hardening a low-flow filling material in the space between the cradle and the composite mat, wherein the low-flow filling material comprises 90 to 92% by weight of a filler including fly ash and steelmaking slag, and calcium alumina. It consists of 8 to 10% by weight of a binder consisting of 85 to 90% by weight of nate-based material, 3 to 5% of cement, and 5 to 10% by weight of calcium sulfoaluminate-based material. It is characterized in that a thickener is additionally formulated.

According to the present invention, the railway slope requiring repair is divided into at least two sections along the vertical direction, the low flow filling material is first filled and cured in the lower section, and then the low flow filling material is filled in the upper section, and the filler When the combined weight of the and the binder is 100, the low flow filler filled in the lower section is formulated with a thickener of 3.1 to 4 parts by weight, and the mixing ratio of water to the low flow filler (W / B, weight ratio) is 70 to 80%, It is preferable that the low fluidity filler filled in the upper section contains a thickener in an amount of 2 to 3 parts by weight, and the mixing ratio (W/B, weight ratio) of water to the low fluidity filler is 80 to 100%.

In addition, according to an example of the present invention, when supplying water to the composite mat, 0.01 to 0.1 parts by weight of polycarboxylate, 0.03 to 0.3 parts by weight of polynaphthalenesulfonate and polylignosulfonate based on 100 parts by weight of water It is preferable to add any one of 0.03 to 0.3 parts by weight.

According to an example of the present invention, it is preferable to increase the flexural strength of the super-fast-hard binder by blending openwork fiber or wollastonite in an amount of 0.1 to 1% by volume relative to the super-fast-hard binder.

In the present invention, loss of the filling material on the slope can be prevented by using a low flow filling material to fill the space on the back of the composite mat.

In particular, while first injecting the filling material into the lower section of the slope, the loss of the filling material is prevented by lowering the mixing ratio of water and raising the mixing ratio of the thickener to extremely lower fluidity and impart plasticity. After the backfilling of the lower section is completed, the injection efficiency can be increased by performing backfilling in the upper section with the liquidity relatively increased.

On the other hand, even if the effects are not explicitly mentioned here, it is added that the effects described in the following specification expected by the technical features of the present invention and their provisional effects are treated as described in the specification of the present invention.

1 is a photograph showing the damage situation of a railroad slope due to torrential rain.
Figure 2 is a schematic flow chart of a railway slope repair and reinforcement method according to an example of the present invention.
3 to 6 are views for explaining a railway slope repair and reinforcement method according to an example of the present invention.
7 is a schematic cross-sectional view of a composite mat used in the present invention.
8 is a schematic cross-sectional view showing a state in which a composite mat is installed on an inclined surface.
9 and 10 are results of experiments on the loss rate of water according to the inclination angle.
※ It is revealed that the accompanying drawings are illustrated as references for understanding the technical idea of the present invention, and thereby the scope of the present invention is not limited.

In describing the present invention, a detailed description thereof will be omitted if it is determined that a related known function may unnecessarily obscure the subject matter of the present invention as it is obvious to those skilled in the art.

An object of the present invention is to provide a method for restoring a damaged railroad grade embankment slope. However, the application target of the present invention is not necessarily limited to the embankment slope, and can be applied not only to the embankment slope of general roads but also to cut slopes other than embankment. That is, it is revealed in advance that the present invention is applicable to all slopes regardless of objects such as railways and roads, and forms such as embankment and incision.

Hereinafter, with reference to the accompanying drawings, a railway slope repair and reinforcement method according to an example of the present invention will be described in more detail.

Figure 2 is a schematic flow chart of a railway slope repair and reinforcement method according to an example of the present invention. In FIG. 2, it is shown that after performing the step indicated by B, the procedure indicated by B is performed. However, procedure A is the realm of actual construction, and procedure B is a procedure to set construction conditions. To be precise, procedure B only needs to be completed before performing the procedure of supplying water to the composite mat in procedure A. Hereinafter, for convenience of description, after all procedures A are described, procedure B for supplying water and setting the supply time will be described in detail later.

3 shows a damaged area (A) as the railroad embankment slope (S) collapsed due to torrential rain. In the present invention, as shown in FIG. 4, first, the cradle 20 is installed on the damaged railroad embankment slope. The cradle 20 may use a wooden or steel frame. The cradle 20 is installed parallel to the slope of the embankment slope and is fixed to the embankment slope. The cradle may be installed in a matrix form as shown in FIG. 4 or may be installed in a row in a longitudinal or transverse direction.

After the cradle 20 is installed, the composite mat 10 is installed on the cradle 20 as shown in FIG. 5 . As shown in FIG. 7 , the composite mat 10 has a structure in which an upper sheet 11 and a lower sheet 12 are spaced apart from each other in the vertical direction, and a super-fast binder (b) is filled therebetween. The composite mat 10 can be manufactured in various ways, and the top sheet and the bottom sheet may be joined by needle punching, or the periphery of the composite mat may be sealed by heat sealing. In addition, a cell structure or lattice structure may be installed inside to prevent the filler from leaning to one side. The top sheet 11 of the composite mat 10 is made of woven or non-woven fabric and has water permeability so that water can pass therethrough. The lower sheet 12 may be made of both water permeable and water impermeable materials. In the case of water permeability, it is advantageous to develop the strength of the binder because it can discharge water that has flowed into the composite mat but has not participated in the hydration reaction with the binder. The impervious sheet is effective in maintaining the stability of the embankment slope by preventing water from penetrating into the embankment slope during rain after construction is completed.

In this example, the super-fast-hardening binder must react with water and be hydrated in a short time to develop strength. Damage to the railroad bed can cause great danger, and even if there is no danger, damage recovery must be done quickly to ensure train operation. To this end, in this example, a CA-based fast-hardening material blended in the range of 60 to 80% by weight of calcium aluminate-based material and 20 to 40% by weight of gypsum is used as an ultra-fast-hardening binder. In addition, cement is mixed in the range of 11 to 42% by weight based on 100% by weight of CA series fast hardwood. As the calcium aluminate-based material, materials such as CaO·Al ₂ O ₃ or 12CaO ₇ ·Al ₂ O ₃ may be used, and all react quickly with water to form hydrates. In particular, in the presence of anhydrous gypsum, slaked lime and alkaline turmeric salts, calcium aluminate-based materials are hydrated more rapidly. In addition, a curing accelerator and a hydration retardant may be additionally blended and used.

In this example, 560 g of C ₁₂ A ₇ , 240 g of anhydrite, and 200 g of cement were mixed to make an ultra-fast binder, and a specimen was made with a water / binder ratio of 35%, and the compressive strength was measured for 4 hours. The compressive strength was found to be 60 MPa, far exceeding the standard strength of 20 MPa. When the water ratio exceeded 32%, hydration proceeded, and when the water ratio exceeded 35%, the compressive strength decreased linearly. To ensure compressive strength, the water/binder ratio (weight) should be maintained at a level of 33 to 50%.

In addition, a fibrous mineral such as openwork fiber or wollastonite may be added to increase the flexural strength of the super-fast binder. The fibrous mineral may be blended in the range of 0.1 to 1% by volume with respect to the super-fast binder.

When the composite mat 10 is installed, water is supplied through the top sheet 11 of the composite mat 10 . As will be described later, although water alone may be supplied, it is preferable to mix and supply a surfactant as in this example. Water meets with the super-fast-hardening binder filled inside the composite mat and causes a hydration reaction to harden the super-fast-hardening binder.

After the binder in the composite mat 10 is hardened, the space V between the composite mat 20 and the damaged embankment slope 10, that is, the area where the holder 20 is installed, is filled with a low flow filling material. Low-flow fill material should be used to prevent loss of fill material when pouring on a slope. The low flow filling material is composed of a filler and a binder. The filler can be understood as the concept of 'aggregate' in the field of cement, and fly ash and steelmaking slag can be used alone or in combination. In addition, some soil may be mixed and used. And the binder is for mutually integrating the fillers. It is formulated with 90 to 92% by weight of filler and 8 to 10% by weight of binder.

The binder is used as a main raw material by mixing 85 to 90% by weight of calcium aluminate-based material, 3-5% by weight of cement, and 5-10% by weight of calcium sulfoaluminate-based material. For example, materials such as C ₁₂ A ₇ , C ₃ A, and CA may be used for the calcium aluminate type, and materials such as C ₄ A ₃ S may be used for the calcium sulfoaluminate type.

And in the present invention, the liquid thickener is mixed immediately before injection in a state where water is mixed with the above low-flow filler. In this example, the fluidity of the filler is controlled by the mixing ratio of water and thickener.

The low flow filling material (F) of the above composition may be filled in the back space of the composite mat at once, but in this example, the upper section and the lower section are divided along the slope, and the low flow filling material is first injected into the lower section and then , Filling material can be filled in the upper section. When the filling material is injected by dividing the section in this way, the fluidity of the low flow filling material is adjusted differently. Since the space where the filling material is filled is an inclined surface, the steeper the slope, the more the filling material can flow downward. In particular, there is a gap between the composite mat and the inclined surface, and the filling material may be lost along this gap. Accordingly, it is preferable to first fill and cure the lower section with a low-flow filling material to which fluidity is further lowered and plasticity is imparted. When the low flow filler is hardened in the lower section, it is advantageous to increase the injection efficiency by adding a little more fluidity in the upper section.

When the total weight of the filler and binder is 100 for the low-fluidity filling material injected into the lower part of the slope, the thickener is mixed in 3-4 parts by weight, and the mixing ratio of water to the low-fluidity filling material (W/B, weight ratio) is 70-80%. do. As the amount of water decreases and the thickener increases, the fluidity rapidly decreases. However, the filler filled in the upper section is formulated with 2 to 3 parts by weight of the thickener, and the mixing ratio (W/B, weight ratio) of water can be relatively high at 80 to 100%. Here, the upper section and the lower section are not bounded by the middle along the height direction of the slope, and the lower section is set with only a slight section at the lower end of the slope. Since it blocks the gap, it is only necessary to set it within a slight section of the lower part, for example, within 20% in the height direction.

As described above, when hardening is completed after backfilling the low-flow filler (F), the state of FIG. 6 is obtained, and the repair and reinforcement of the embankment slope is completed.

An important point to consider in the railway slope repair and reinforcement method performed according to the above procedure is that the composite mat is installed on the slope. This is because there is a very large difference between installing the composite mat on a slope and installing it on a flat surface, and if the slope conditions are not accurately considered, the hydration of the initial and high-speed binder may not be sufficiently achieved. In addition, as described in the prior art, the railway slope is difficult to access, and there is a difficulty in shortening the construction time as much as possible for train operation. In other words, while completing the construction in the shortest possible time, it is necessary to complete the construction so that the composite mat can be completely hydrated.

The first feature of the present invention is to determine the amount of water (actual supply amount) to be supplied to the composite mat and the total supply time for which time the actual supply amount is to be supplied in order to satisfy the above two points. This is a procedure for setting construction conditions, which is the area indicated by B in FIG.

Referring to part B of FIG. 2 , in the present invention, specific construction elements are first measured to determine construction conditions. That is, in the present invention, the angle of inclination (θ) between the railroad slope and the ground is measured. In addition, in the composite mat 10 used for restoration shown in FIG. 7, the thickness ( _DS ) and permeability coefficient (P _s ) of the top sheet 11, the volume (V _b ) of the binder filled inside the composite mat, and the thickness (D _b ), porosity (φ _b ) and permeability coefficient (P _b ) of the binder are measured. Among the above construction factors, the angle of inclination of the railway slope is an element that needs to be directly measured, but those related to composite mats can be directly measured or obtained from product information or other literature information.

When the understanding of the construction elements is completed, how much water should be supplied and for how long after the composite mat is installed is calculated. First, since all particles in the composite mat must be in contact with water to hydrate all particles, the amount of water that all particles can contact with water, that is, the theoretical supply amount, was set. In this example, the theoretical supply amount is set when all the water is filled in the voids in the binder.

... 식(1)

... Equation (1)

(Where, W is the theoretical supply of water, Vb is the volume of the binder, φ _b is the porosity of the binder, and ρw is the density of water)

As shown in Equation (1) above, when the volume of the binder (the volume within the composite mat when the composite mat is completely filled) is multiplied by the porosity of the binder, the volume of the voids is obtained. If all pores are filled with water, the theoretical supply of water (W) can be calculated by multiplying the density of water.

After the water is supplied, the time taken to pass through the upper sheet of the composite mat and move to the lower sheet, that is, the arrival time is calculated by Equation (2) below.

... 식(2)

... Equation (2)

(where T is the arrival time, Ds is the thickness of the top sheet, P _s is the permeability coefficient of the top sheet, θ is the inclination angle of the railway slope, D _b is the thickness of the binder in the composite mat, P _b is the permeability coefficient of the binder)

Figure 8 is a schematic cross-sectional view showing a state in which the composite mat is installed along the inclination angle (θ) of the railway slope. Referring to FIGS. 7 and 8 together with Equation (2) above, since the top sheet 11 is tilted by the inclination angle, the thickness of the top sheet through which water must pass is the thickness Ds of the original top sheet 11 It is a value multiplied by 1/cosθ in . Likewise, the thickness of the binder (b) through which water must pass becomes a value obtained by multiplying 1/cosθ by the original thickness (D _b ). In addition, water has a velocity corresponding to the permeability coefficient (P _s , P _b ) of the corresponding layer in the upper sheet layer and the binder layer, respectively. By dividing the thickness of each layer by the permeability coefficient of each layer, the time it takes for water to pass through both the top sheet layer and the binder layer, that is, the arrival time (T), can be calculated. In the case of pressure injection of water into the composite mat, the arrival time can be speeded up, but pressure injection is not easy under inclined conditions, and water is sprayed to penetrate by gravity. Therefore, the arrival time can be obtained in the same way as above.

On the other hand, since the composite mat is installed on the inclined surface, all of the supplied water does not penetrate into the composite mat and some of it flows down along the top sheet. An experiment was conducted on this. The table in FIG. 9 measures the water/cement ratio according to the amount of water supplied by installing the composite mat at an inclination angle of 20 degrees in a state in which 600 g of cement is filled in the composite mat. Hydration occurs when the water/cement ratio exceeds 30%, and hydration does not occur when the water ratio is less than that. As shown in the table of FIG. 9, when 200 g of water was supplied, the water/cement ratio was 33% with respect to 600 g of cement. That is, it indicates that all the water penetrated into the composite mat. However, as shown in the table of FIG. 10, when the composite mat was installed on a slope of 60 degrees under the same conditions, hydration did not occur even when 300 g of water was supplied, and hydration occurred when 400 g was supplied, and the water / cement ratio was 39.7%. That is, it means that about half of the water in the above case did not penetrate into the composite mat. In other words, it means that we have to supply twice the theoretical supply. As a result of the experiment by changing the angle, the degree of water penetration decreased according to the angle of inclination. Therefore, in the present invention, when determining the actual supply amount of water, the theoretical supply amount is used as the reference value up to the inclination angle of 20 °, but 1.5 times the theoretical supply amount is used as the reference value in the inclination angle range of 20 to 40 °, and the theoretical supply amount in the inclination angle range of 40 to 60 ° 2 times the standard value. In addition, the actual supply of water is supplied within the range of 1.1 to 1.3 times the above reference value in consideration of the margin.

When the actual water supply amount and arrival time are determined as above, the water supply amount (Wu) per unit time is determined by dividing the actual water supply amount (Wr) by the arrival time (T) as shown in Equation (3) below.

... 식(3)

... Equation (3)

If the water supply amount per unit time determined in this way is supplied during the total arrival time T, all of the actual supply amount can permeate the binder inside the composite mat, and all of the binders can meet with water to participate in hydration. Since the binder participates in hydration, the strength of the composite mat can be guaranteed equal to the design strength.

Without these design elements, the composite mat installed on the slope cannot supply enough water to fully hydrate. In other words, even if a lot of water is supplied at once, it cannot participate in the actual hydration reaction because all the water is discharged along the slope. Conversely, if water is supplied slowly and slowly for a long time, the construction time will be longer than necessary, causing disruptions to train operation. Furthermore, when the lower sheet of the composite mat is made of an impervious material, since water in the composite mat is supplied in excess, the water/binder ratio increases, which may cause a problem in that the strength of the composite mat is not expressed. That is, according to the present invention, the amount of water supplied so that all the binders can participate in hydration is determined in consideration of the angle of inclination of the slope, the coefficient of permeability, etc., and the amount of water supplied per unit time can be determined so that all of this water can penetrate into the composite mat. . When water is supplied according to the above construction conditions, construction can be completed in the fastest time under conditions that guarantee durability such as the strength of the composite mat.

On the other hand, the present invention focused on the fact that the wetting of the binder should be increased in order for water to penetrate all the pores. That is, water is supplied to the binder in a powder state, but if the wettability of the powder is low, water may not penetrate into pores trapped by the powder particles due to surface tension. Therefore, in the present invention, the wettability (hydrophilicity) of the binder powder is increased by mixing and supplying the surfactant with water.

As the surfactant, polylignosulfonate, polynaphthalenesulfonate, polycarboxylate, etc. can be used. In the case of polycarboxylate, 0.01 to 0.1% by weight of water, and polynaphthalenesulfonate and polylignosulfonate are water. About 0.03 to 0.3% by weight is used.

As described above, the present invention provides a repair and reinforcement method for the railway roadbed embankment slope. In the present invention, a composite mat is used, and considering that the composite mat is installed on a slope, the water supply amount, the water supply time, and the water supply amount per unit time are carefully calculated. Through this, all of the ultra-fast-hardening binder powder in the composite mat reacts with water to be hydrated, so that the design strength is sufficiently expressed. In addition, it has the advantage of being able to secure train operation time as the restoration work is completed in the shortest time while quality is guaranteed.

In addition, in the present invention, loss of the filling material on the slope can be prevented by using a low flow filling material to fill the back space of the composite mat. In particular, while first injecting the filling material into the lower section of the slope, the loss of the filling material is prevented by lowering the mixing ratio of water and raising the mixing ratio of the thickener to extremely lower fluidity and impart plasticity. After the backfilling of the lower section is completed, the injection efficiency can be increased by performing backfilling in the upper section with the liquidity relatively increased.

The protection scope of the present invention is not limited to the description and expression of the embodiments explicitly described above. In addition, it is added once again that the scope of protection of the present invention cannot be limited due to obvious changes or substitutions in the technical field to which the present invention belongs.

10 ... composite mat, 20 ... cradle
S ... embankment slope, A ... damage

Claims (4)

(a) installing a cradle on a damaged railway slope;
(b) installing a composite mat having a water-permeable top sheet, a bottom sheet coupled to a lower portion of the top sheet, and a super-fast binder in a powder state filled between the top sheet and the bottom sheet on the cradle;
(c) supplying water through the upper sheet of the composite mat to cure the super-fast binder; and
(d) filling and hardening a low flow filling material in the space between the cradle and the composite mat;
The low-flow filling material is composed of 90 to 92% by weight of filler including fly ash and steelmaking slag, 85 to 90% by weight of calcium aluminate-based material, 3-5% by weight of cement, and 5-10% by weight of calcium sulfoaluminate-based material. It is made of 8 to 10% by weight of the binder,
The low flow filler is a railway slope repair and reinforcement method, characterized in that the liquid thickener is additionally formulated in a mixed state with water. According to claim 1,
Dividing the railway slope requiring repair into at least two sections along the vertical direction, first filling and hardening the low flow filling material in the lower section, and then filling the upper section with the low flow filling material,
When the total weight of the filler and the binder is 100, the low flow filler filled in the lower section is formulated with a thickener in 3 to 4 parts by weight, and the mixing ratio of water to the low flow filler (W/B, weight ratio) is 70 to 80 %, the low flow filler filled in the upper section is formulated with a thickener of 2 to 3 parts by weight, and the mixing ratio (W / B, weight ratio) of water to the low flow filler is 80 to 100%. Method. According to claim 1,
When supplying water to the composite mat,
Railway slope repair characterized by adding any one of 0.01 to 0.1 parts by weight of polycarboxylate, 0.03 to 0.3 parts by weight of polynaphthalenesulfonate, and 0.03 to 0.3 parts by weight of polylignosulfonate based on 100 parts by weight of water. reinforcement method. According to claim 1,
Railroad slope repair and reinforcement method, characterized in that openwork or wollastonite is blended in the range of 0.1 to 1% by volume relative to the ultra-fast binder.

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