KR20200137058A - Patent for earth-pressure mitigation method affecting 'reinforced soil retaining wall' using 'perforated triangular drain pipe' - Google Patents

Abstract

The present invention relates to a drain induction method using a perforated drainpipe having a triangular cross section, which is a drain method for reducing water pressure generated in a rear part of a retaining wall, which is a main cause for the collapse of an existing reinforced soil retaining wall of civil-engineering works. Water pressure generated on the rear side of a retaining wall can be generated due to a natural rainwater permeation condition or other conditions such as a poor compacting state of retaining wall backfilling, a geographical underground water level and the like, and the water pressure can cause the deformation of a masonry type form of panel blocks or prefabricated blocks of a reinforced soil retaining wall by increasing a water level on the rear side of the retaining wall, which can lead to collapse having a risk due to the imbalance of the wall. Water stagnating on the rear side of a retaining wall is naturally drained at all times through a drainpipe to remove water pressure, and an outlet, which is morphologically difficult to make on a panel surface or a block of an outer wall surface of a retaining wall, is made into a small triangular shape such that applicability can become higher. In other words, the present invention is a drain method using a triangular drainpipe.

Description

Patent for earth-pressure mitigation method affecting'reinforced soil retaining wall' using'perforated triangular drain pipe'}

The present invention is a drainage method capable of reducing the water pressure generated on the back side of the retaining wall, which is the main cause of the collapse of the existing reinforced soil retaining wall in civil works, and is a direct water pressure exclusion method using a drainage perforated pipe having a triangular cross section.

The domestic reinforced earth retaining wall was introduced in the late 1970s, and in 1980, a panel-type reinforced earth retaining wall using galvanized steel was applied (test construction), but it was not activated due to problems such as lack of zinc plating technology and economic feasibility.

In 1986, with the introduction of a panel-type reinforced soil retaining wall with a strip-type geotextile reinforcement and a concrete panel, it began to be applied to roads and site construction. The application performance of reinforced soil retaining walls is increasing exponentially. However, damage cases continue to occur due to lack of awareness and understanding of the reinforced soil retaining wall by field engineers.

Reinforced soil retaining walls used in Korea can be divided into panel-type reinforced soil retaining walls using concrete panels and block-type reinforced soil retaining walls using small blocks.In addition, various construction methods such as reinforced soil temporary facilities and vegetation reinforced soil retaining walls are applied.

Problems of reinforced soil retaining walls

1. Problems of existing reinforced soil retaining walls

If the backfilling part is insufficiently compacted, subsidence occurs, the front part of the retaining wall is filled, water pressure is generated if the backfilling rubble and soil is bad. Also, in the case of soft ground, the foundation of the retaining wall is constructed or the foundation is laid. It must be improved.

2. Problems of reinforced soil retaining walls during the rainy season

During the rainy season, soil and drainage between the front walls (bulk, panels), rainwater that cannot be drained out compared to the amount of inflow per hour generates water pressure, and large-scale retaining walls may collapse due to water pressure.

As such a water pressure reduction method, a drainage hole, which is a water pressure reduction facility, must be directly installed along with the complete construction of the backfill aggregate of the reinforced soil retaining wall.

The present invention is to reduce the water pressure of the existing reinforced soil retaining wall, even if the backfilling aggregate is completely constructed, the drainage function of the aggregate is remarkably reduced as the soil is filled between the aggregates as time elapses. Retaining wall collapse and large-scale collapse including structures may occur. Therefore, I recommend suggesting a triangular drainage facility, which is a direct hydraulic relief facility.

The function of this invention directly excludes rainwater and residual water in the ground and reduces residual water pressure and earth pressure.

The shape of this invention is to install a triangular drainage hole between the reinforced soil retaining wall and the reinforced soil retaining wall. The shape of the triangular drain hole is the same as in [Drawing 1], and it is a regular triangle in cross section with 60 mm on one side, and there is a drain hole (CTC@30) with a spacing of 30 mm on the surface.

The installation method of this invention is that this triangular drainage pipe is used according to the required length according to the design drawing or site conditions, and it is installed in the ground by wrapping a non-woven or curing cloth to prevent soil from entering the drainage pipe. It is basic to install one place for every three stages, but the spacing and arrangement method can be adjusted and installed according to the expected quantity and expected amount of rain at the location where the reinforced soil retaining wall will be installed. Refer to sectional view and front view [Fig. 2]

The material of this invention should be selected differently depending on the installation site or environmental conditions.

1) Reinforced polyethylene

The biggest feature is that it is inexpensive and easy to process, so it is suitable for mass-produced products, but it is weak against fire or heat.

2) Steel pipe

The biggest feature is that it is not easily deformed and is strong, but it is relatively heavy and there is a risk of corrosion at the cut part.

3) stainless

The biggest feature is that it has excellent strength and can be manufactured with a thin thickness, but the manufacturing cost is higher than other products.

As such a water pressure reduction method,

First, complete construction of backfill aggregates to reduce the water pressure of the reinforced soil retaining wall

Second, it is maintained so that there is no deformation or leakage of soil on the back of the retaining wall due to rain or buoyancy.

However, collapse accidents are already frequent in the existing prefabricated reinforced soil block retaining walls, and the Korean weather is also in a situation where rain with heavy rain is falling when it rains, so there is a need to find a more efficient natural drainage method.

By installing a drainage hole, which is the designed water pressure reduction facility, natural drainage can be achieved and water pressure can be reduced by lowering the groundwater level or buoyancy on the back of the retaining wall.

Drawing 1: This is a detailed drawing of a triangular drainage hole (triangular drainage pipe), which is a representation of the shape and size of the triangular drainage pipe with dimensions.
Drawing 2: Installation location diagram (cross-sectional view and front view), the installation location is marked on the cross section, and the length of the drain pipe installation should be followed according to the site conditions.
Figure 3: This is a layout drawing, showing a method of arranging a triangular drain pipe. Place a triangular drainage hole with a cross section of 60 mm between the reinforced soil blocks and continue the masonry work.
The drain pipe must be wrapped with non-woven fabric, but the non-woven fabric should not be wrapped around the exposed part, which is the end of the discharge port located on the front of the retaining wall, and the part where blocks meet each other.
For reference, the reinforced soil block used as an example is based on the size of 1 width*length*height = 420 mm * 420 mm * 200 mm. (Refer to Internet data: Kyungil Concrete Search: Kyungil Concrete -> Reinforced Soil Blocks -> Combs Reinforced Soil Refer to C type retaining wall block)

1. As a limitation,

1) General

The reinforced soil retaining wall is theoretically independent of the height, and generally has economically advantageous features when installing a retaining wall with a height of 5 m or more. However, the stability of the reinforced soil retaining wall greatly affects depending on the properties of the material and construction skill level during actual construction. At the time when the recent collapse of the reinforced soil retaining wall, the orderer (Blue) is in a position to be reluctant to apply new technology to the reinforced soil retaining wall.

2) natural disaster

In recent years, local heavy rains have increased and the amount of rain has been recorded. Retaining walls that have not been drained due to the record heavy rains often burst without withstanding water pressure.

3) Subcontracted work

There are frequent collapse accidents, such as fullness due to poor backfilling material and poor reinforcement, and damages are continuing.

4) Restrictions according to laws

Although the height of cutting and embedding is limited, such as the Mountain Management Act, other laws have been applied to deviate from the restrictions on height, and unfilled and deliberate accidents have occurred. Reinforced soil retaining walls are removed due to lack of constructability (without reinforcement) due to the installation of small beds.

2. As a future plan,

1) As a policy, if there is no support and enforcement for new construction methods and new technologies, it will be practically impossible.

2) If the construction and stability of the reinforced soil retaining wall are complemented in the future, and demand increases, it will be possible to remove the collapse of the reinforced soil due to water pressure in advance by grafting not only the triangular drainage system studied so far, but also the drainage using the front wall.

Claims (2)

The shape of this triangular drainage hole is the same as in [Drawing 1],
It is a regular triangle in cross section with 60 mm on one side, and there is a drain hole (CTC@30) with a spacing of 30 mm on the surface. Installation is between the bricks (or panels) of the reinforced soil retaining wall, with an interval of one for each of three horizontal and three vertical levels, and the pipe end is exposed on the front of the retaining wall. Directly to the outside. Cross-sectional view, front view [Fig. 2], [Fig. 3] reference

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