KR102625776B1 - Construction method of CIP retaining wall with improved water protection and ground subsidence prevention function - Google Patents

Abstract

The present invention is an improved cast-in-place concrete that can secure sufficient strength in response to earth pressure and have a high order effect, and can prevent groundwater inflow into the borehole, collapse of the borehole wall, and subsidence of the back ground during construction. (C.I.P) relates to a construction method of an earth retaining wall, and more specifically, a) the step of constructing a plurality of column-type reinforced walls by stirring and mixing the original ground soil and solidifying agent in the ground of the earth retaining target; b) forming drilling holes at regular intervals along the area where the column-type reinforced wall is formed, and inserting reinforcing materials including reinforcing bar nets or H-beams into the selected drilling holes; and c) pouring concrete into the drilled hole into which the reinforcement material is inserted, curing it, and constructing a support wall on the ground on which the column-type reinforced wall was constructed.

Description

Construction method of CIP retaining wall with improved water protection and ground subsidence prevention function}

The present invention is an improved cast-in-place concrete that can secure sufficient strength in response to earth pressure and have a high order effect, and can prevent groundwater inflow into the borehole, collapse of the borehole wall, and subsidence of the back ground during construction. (C.I.P) Concerns the construction method of earth retaining walls.

Domestic earth retaining wall construction methods include H-Pile earth wall, soil cement wall (S.C.W), high-strength earth retaining wall (H.S.W), cast-in-place concrete wall (C.I.P), and concrete underground continuous wall (slurry wall) construction method, respectively. Due to its characteristics, the most advantageous retaining wall construction method for site conditions is selected and applied during the design process.

In urban areas and soft strata conditions, the method mainly applied when constructing a temporary earth retaining wall with a relatively deep underground excavation depth is the column-type cast-in-place concrete wall (C.I.P.). Although not shown in a separate drawing, this method uses rebar or H-beam steel after drilling. This is a method of forming a column-type earth retaining wall by continuously constructing concrete piles filled with concrete after adding reinforcing materials such as reinforcing materials.

This cast-in-place concrete retaining wall (C.I.P.) construction method is a temporary retaining wall and is mainly applied to narrow areas and soft ground conditions in urban areas. However, when excavating underground floors, only the cast-in-place concrete retaining wall (C.I.P.) is used to prevent groundwater flowing in from the back ground. Because a 100% water blocking effect cannot be expected, separate water blocking grouting must be done on the back of the temporary retaining wall. If a problem occurs with the quality of the retaining wall, the settlement and cavities in the ground behind the retaining wall during underground layer excavation may cause damage to the temporary retaining wall. This can be a major cause of collapse.

Meanwhile, the method of manufacturing a water barrier using the CIP method using a scratch structure in Korean Patent Publication No. 10-2017-0059298 suggests a method of securing water barrier without separate water barrier grouting in the CIP method, but the work process is complicated and the quality is poor during construction. Difficulty in management appears to be a disadvantage.

In particular, in the CIP method according to the prior art, drilling into the ground is performed without considering the engineering soil characteristics of the ground under construction, such as the east coast area composed of sandy soil layer (sand layer) or the west coast composed of soft ground (clay layer). As this is done, the inflow of groundwater into the hole during ground drilling and the collapse of the hollow wall during the casing pulling process after concrete pouring may occur. Furthermore, even after the construction of the retaining wall, settlement may occur in the rear ground due to water leakage flowing between the retaining walls. There is a problem that this may lead to a major accident such as the collapse of temporary earth retaining facilities.

Republic of Korea Patent Publication No. 10-2017-0059298

Therefore, the present invention was devised to solve the above-mentioned problems, and is an improved column type that can have a high order effect while securing sufficient strength in response to earth pressure, and can prevent the collapse of the hollow wall and the settlement of the ground behind the temporary earth retaining facility. The purpose is to provide a construction method for cast-in-place concrete (C.I.P.) retaining walls.

As a means to solve the above-mentioned problems, the construction method of the CIP earth retaining wall with improved water resistance and ground settlement prevention function of the present invention (hereinafter referred to as the "construction method of the present invention") is: a) the original ground in the ground of the earth retaining target; Constructing a plurality of column-type reinforced walls by stirring and mixing soil and solidifying agent; b) forming drilling holes at regular intervals along the area where the column-type reinforced wall is formed, and inserting reinforcing materials including reinforcing bar nets or H-beams into the selected drilling holes; and c) pouring and curing concrete into the drilled hole into which the reinforcing material is inserted, and then constructing a support wall on the ground on which the column-type reinforced wall was constructed.

As an example, steps b) to c) include forming a plurality of first drilling holes at a constant distance from each other along the ground on which the column-type reinforced wall is formed; Inserting a reinforcing material including a reinforcing bar network or an H beam into the first drilling hole; Constructing a first support wall by pouring and curing concrete into the first perforated hole into which the reinforcement material is inserted; A plurality of second perforations are located at a relatively greater distance from the direction in which the back earth pressure acts between the two adjacent first supporting walls than the row in which the first supporting walls are constructed, and the main surfaces are in contact with the main surfaces of both first supporting walls. forming a hole; and pouring and curing concrete into the second perforation hole to construct a second support wall connected to the first support wall.

As an example, it is characterized by further including the step of constructing water blocking grouting in the spaced apart space between the two adjacent second support walls.

As an example, in step a), the column-type reinforced walls are characterized in that they are constructed overlapping each other.

According to the construction method of the present invention, the ground on which the retaining wall is to be constructed is reinforced in advance through a high-strength deep mixing method (High strength D.C.M.; H.D.C.M.), and then a supporting wall functions as a structure in the ground. By post-construction, it is possible to secure sufficient strength in response to earth pressure and have a high order effect. In particular, there is an advantage in preventing the collapse of the hollow wall and subsidence of the underlying ground that may occur during the drilling process to form an earth retaining wall. there is.

In addition, since the casing penetration process required when constructing an earth retaining wall on soft ground is unnecessary, not only the construction time but also the construction cost is reduced, which not only improves constructability but also improves economic efficiency.

1 is a block diagram showing the construction method of the present invention.
Figure 2 is a plan view showing a basic example of an earth retaining wall constructed by the construction method of the present invention.
Figure 3 is a plan view showing an earth retaining wall with reinforced stability constructed according to another embodiment of the present invention.
Figure 4a is a plan view showing the waterline grouting construction points of a typical main heat retaining wall.
Figure 4b is a plan view showing water grouting construction points of an earth retaining wall constructed according to another embodiment of the present invention.

In describing the present invention, the terms and words used in the specification and claims are based on the principle that the inventor can appropriately define the concept of the term in order to explain the invention in the best way. It must be interpreted with meaning and concepts consistent with the technical ideas of.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

Referring to Figures 1 and 2, the construction method of the present invention includes the step (S100) of constructing a plurality of heat-type reinforced walls (10) by stirring and mixing the original soil and solidifying agent in the ground of the ground to be retained. Forming drilling holes at regular intervals along the area where the column-type reinforced wall 10 is formed, inserting reinforcing material 200 including a reinforcing bar network or H beam into the selected drilling hole (S200), and the reinforcing material 200 ) includes the step (S300) of pouring and curing concrete into the inserted drill hole and then constructing a plurality of support walls 20 on the ground strengthened by the construction of the main heat-reinforced wall 10.

The S100 step is a process of solidifying and improving the ground for construction prior to constructing the retaining wall and reinforcing it.

In this step (S100), the ground area can be solidified and improved using the high strength deep mixing treatment method (High strength D.C.M. (H.D.C.M)).

As an example, this step (S100), which is not shown in the drawing, includes forming a perforated wall by penetrating an auger device into the ground area, and supplying a solidifying agent to the ground where the perforated wall is formed using the auger device, It may be configured to include the steps of stirring and mixing the original ground soil and solidifying agent using the auger device and compacting the perforation wall, and the step of pulling out and separating the auger device from the ground area.

In this step (S100), a plurality of column-type reinforced walls 10 are formed by repeating the above-described detailed process and continuously constructing the earth retaining ground in a column type.

At this time, it is preferable that the column-type reinforced walls 10, which are continuously constructed, are constructed overlapping each other to prevent disconnection of the reinforcement section on the ground where the retaining wall is to be constructed.

Accordingly, it is possible to have more effective water blocking performance, and during the construction of the support wall 20 in the post-process, it is possible to prevent collapse of the hollow wall and subsidence of the back ground due to groundwater inflow into the drilling hole.

Additionally, it is desirable to use an eco-friendly solidifying agent to minimize contamination to the ground.

The auger device is a drilling device for a high-strength earth retaining continuous wall or a deep mixing treatment method. It can suppress slime discharge by controlling the dispersion and disturbance of soil in the process of penetrating into soft ground, and sprays a solidifying agent through one device. After this, it can be configured to perform mechanical stirring between the solidifying agent and the soil.

Here, the auger device can be used by selecting an appropriate one among various known devices in consideration of the soil quality of the original ground and the working environment, etc., and a detailed description thereof will be omitted.

Meanwhile, step S200 is a process of forming drilling holes at regular intervals along the area where the column-type reinforced wall 10 is formed, and inserting reinforcing material 200 including a reinforcing bar network or H beam into the selected drilling hole.

In step S200, a guide wall facility can be installed in advance to guide the penetration of the auger device and secure the verticality of the drilling hole.

When a guide wall facility is applied to construction, additional processes such as line digging of the ground for placement and installation of the guide wall facility, and backfilling and compaction of the ground on the side of the guide wall facility may be further included.

Step S300 is a process of pouring concrete into the hole formed in step S200, curing it, and constructing an earth retaining support wall 20 within the area of the pre-constructed main heat reinforced wall 10.

That is, the construction method of the present invention is to first reinforce the ground on which the retaining wall is to be constructed through a high-strength deep mixing method (High strength D.C.M.; H.D.C.M.), and then build a support wall (20) that functions as a structure in the ground. ) will be installed later.

In this way, in the present invention, the column-type reinforced wall 10 and the support wall 20 are constructed overlapping in the same ground area, thereby ensuring sufficient strength in response to earth pressure and having a high order effect. In particular, the support wall 20 It is possible to prevent groundwater inflow into the bore hole, collapse of the cavity wall, and subsidence of the underlying ground that may occur in the process of forming.

In addition, since the casing penetration process required when constructing an earth retaining wall on soft ground is unnecessary, not only construction time but also construction cost can be reduced.

Meanwhile, in one embodiment of the present invention, as shown in FIG. 3, the support walls 20 may be arranged in two rows while being spaced apart from each other on the ground on which the column-type reinforced wall 10 is formed.

Specifically, steps S200 to S300 according to the present embodiment include forming a plurality of first drilling holes so as to have a certain distance from each other along the ground on which the column-type reinforced wall 10 is formed, and the first drilling holes The steps of inserting reinforcing material 200 including a reinforcing bar network or H beam into the concrete, pouring concrete into the first drill hole into which the reinforcing material 200 is inserted, curing it, and constructing the first support wall 21. It can be included.

And, between the two adjacent first support walls 21, the first support walls 21 are located at a relatively greater distance from the direction in which the back earth pressure acts than the row in which the first support walls 21 are constructed, and have both main surfaces. Forming a plurality of second perforated holes to be in contact with the main surface of and pouring concrete into the second perforation holes, curing it, and constructing the second supporting wall (22) connected to the first supporting wall (21). may include.

At this time, according to FIG. 3, the second support wall 22 is shown as a bare wall with the reinforcement material 200 excluded, but the present invention is not limited to this and, like the first support wall 21, the second support wall 22 has a second perforation. The step of inserting a reinforcing material 200 including a rebar network or an H beam into the hole may be further included.

That is, in this embodiment, a plurality of first support walls 21 are arranged to be spaced apart from each other at a certain interval in front of the ground where the column-type reinforced wall 10 is formed, and where earth pressure is directly applied, and the first support walls 21 are placed behind them. A support wall is constructed between the walls 21 so that the main surface of the second support wall 22 is in contact with them.

In general, since the auger device for forming the drilling hole imposes an excessive load on the shear, the work is performed while correcting the penetration verticality of the auger device in the process of forming the drilling hole for the construction of the support wall 20.

However, this correction work is only effective at the beginning of penetration, and errors occur as the auger device goes lower into the ground, so the penetration verticality of the auger device gradually becomes distorted, causing separation at the interface between continuously constructed drilling holes. This forms a gap between the supporting walls 20 during construction of the supporting walls 20 in a row, allowing it to function as an inflow point of groundwater during ground excavation.

Accordingly, in this embodiment, after constructing a plurality of first support walls 21, a second support wall 22 is constructed between the first support walls 21 at the rear end of the first support wall 21. As such, not only is the penetration of the auger device guided into the separation space formed between the pre-constructed first support walls (21), but also the auger device is supported on the main surfaces of both first support walls (21) during the process of forming the second drilling hole. Drilling can be performed as long as the condition is maintained.

Therefore, a uniform boundary surface is formed between the pre-constructed first support wall 21 and the newly formed second perforation hole, resulting in the second support wall 22 being constructed by pouring and curing concrete in the second perforation hole. It is possible to prevent the occurrence of a gap with the.

In addition, structurally, the first support wall 21 is a structure of an earth retaining wall, and when earth pressure is applied, the earth pressure is transmitted to the adjacent second support wall 22, so that it can effectively resist the back earth pressure, and the first support wall ( 21) The second supporting wall 22 is placed in contact with the space secured between the walls, so that when the back earth pressure is applied, a pressing effect is applied to the first supporting wall 21, further strengthening the binding force and water blocking performance between the walls. It can provide an effect.

And, in this embodiment, as shown in FIG. 4B, the step of constructing water blocking grouting 30 in the spaced apart space between the two adjacent second support walls 22 may be further included.

When constructing an earth retaining wall, water-blocking grouting (30) is performed on the boundary between walls, which may be relatively vulnerable, for the purpose of preventing the inflow of groundwater and securing watertightness.

In general, when the support walls 20 are constructed in a row as shown in Figure 4a, grouting must be done at each boundary between each support wall 20.

On the other hand, according to the construction method according to this embodiment, as shown in FIG. 4b, the entire boundary area between the two walls is covered by only constructing one spot of water grouting 30 in the space spaced apart between the two second support walls 22. You can do it.

Therefore, not only are the groundwater inflow points minimized, but the construction locations for the water cut grouting (30) are relatively reduced compared to the linear arrangement structure of the wall, so not only the construction time required for water cut grouting (30) but also the construction cost can be reduced. There is a possible effect.

At this time, in the case of the water barrier material used in the water barrier grouting, in order to achieve a sufficient pressing effect as described above, it is relatively softer and watertight than the concrete poured when constructing the first and second support walls 21 and 22. It is desirable to use the material, and it is natural that non-shrinkage order admixtures, etc. may be added considering the engineering soil characteristics of the original ground.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims are also possible. falls within the scope of rights.

10: Main heat reinforced wall 20: Support wall
21: first support wall 22: second support wall
30: Water grouting 200: Reinforcement material

Claims (4)

A step (S100) of constructing a plurality of column-type reinforced walls by stirring and mixing the original ground soil and solidifying agent in the ground of the target ground for earth retaining, and constructing the continuous column-type reinforced walls so that they overlap each other;
Forming a plurality of first drilling holes in the ground so as to have a certain distance from each other along the area where the plurality of column-type reinforced walls are formed (S200);
Inserting a reinforcing material including a reinforcing bar network or an H beam into the first drilling hole (S300);
Step (S400) of pouring and curing concrete into the first perforated hole where the reinforcing material is inserted and constructing the first support wall side by side within the pre-constructed column-type reinforced wall area;
A plurality of second perforations are located at a relatively greater distance from the direction in which the back earth pressure acts between the two adjacent first supporting walls than the row in which the first supporting walls are constructed, and the main surfaces are in contact with the main surfaces of both first supporting walls. Forming a hole (S500);
A step (S600) of pouring and curing concrete into the second perforation hole to construct a second support wall connected to the first support wall within the pre-constructed main heat reinforced wall area; and
Includes a step (S700) of constructing water blocking grouting in the spaced apart space between the two adjacent second support walls,
In step S100,
A step of penetrating an auger device into the ground area to form a perforated wall, supplying a solidifying agent to the ground where the perforated wall is formed using the auger device, agitating the original ground soil and a solidifying agent using the auger device, and A method of constructing a CIP retaining wall with improved water protection and ground subsidence prevention functions, characterized in that the steps of mixing and consolidating the perforated wall and the step of pulling and separating the auger device from the ground area are repeated. delete delete delete

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