KR200195274Y1 - Vertical drainage unit for resisting uplift of sub-structure - Google Patents

Abstract

The present invention relates to an underground building buoyancy prevention system.

In general, when a building structure is newly constructed, its own weight (dead load) is generated on the ground of the building structure, and buoyancy due to groundwater acts at the same time. If (positive pressure) is large, the building will be injured and the building structure will be greatly damaged by the increase and decrease of hydraulic pressure.

Therefore, this design considers the groundwater level change condition and installs a simple water level (water pressure) control facility on the floor of the building by applying the grounds for ground engineering and hydraulic engineering to limit the groundwater level where buoyancy is expected. It is a buoyancy prevention system using the principle of basically suppressing buoyancy to be below the groundwater level (water pressure) .It is not discharged in the normal natural water level, but if the height of the groundwater level rises above the height of the drain pipe during the rainy season, Under the natural law, groundwater overflows and drains naturally.

The present invention as described above can be effectively used when the existing structure is affected by the positive pressure (buoyancy) is that the installation is simple and the construction is simple, the overall process management is easy. In addition, it is easy to apply even when there is a large amount of groundwater and difficult to apply other methods, it is a very useful design that can produce a much superior effect compared to the anchor method or general drainage method in consideration of economical efficiency, construction properties, stability.

Description

Vertical drainage unit for resisting uplift of sub-structure}

The present invention relates to an underground building buoyancy prevention system.

In general, when a building structure is newly constructed, as shown in Fig. 1, the ground of the building structure generates self-weight (dead load) due to the building structure, and buoyancy due to groundwater acts simultaneously, in this case, acting on the floor of the building. If the buoyancy (positive pressure) by groundwater is greater than the weight of the building, the building will be injured and the building structure will be greatly damaged by the increase and decrease of hydraulic pressure.

However, when constructing a large-scale building such as an apartment, underground parking is mandatory in recent years, and the underground parking lot of an apartment is located in a lower zone due to the trend of increasing occupants and the desire to secure green space. The buoyancy will be more affected.

Therefore, in order to fundamentally eliminate such adverse effects on the buoyancy buoyant to date, the permanent anchor (Permanent Anchor) to anchor the structure to the lower bedrock generally, and the continuous drainage from the bottom to suppress the buoyancy acting on the floor Dewatering has been used.

However, in the case of the anchoring method, since it is a method of perforating to the rock layer and tensioning and fixing more than the required load after inserting the strands, the construction cost is high, the construction period is long, and a lot of waterproof defects occur in the anchor drilling part. In addition, damage to the structure is easy to occur due to the corrosion and stress reduction of the tensioned steel wire, difficult to repair, and to compensate for this, the re-stretching system has a disadvantage that the construction cost is two or three times more expensive than the general case.

In addition, in the case of the drainage method, the construction cost is simple and the initial construction cost is low. However, the groundwater introduced through the water collection pipe must be permanently drained by a pump. Because of falling, there is a defect that causes settlement of the surrounding ground.

The general countermeasures against buoyancy are needed to minimize the effects of water level spikes during the rainy season rather than natural natural water level conditions. Therefore, this design considers the groundwater level change condition and installs a simple water level (water pressure) control facility on the floor of the building by applying the grounds for ground engineering and hydraulic engineering to limit the groundwater level where buoyancy is expected. Buoyancy prevention system using the principle of basically suppressing buoyancy to be below ground water level (water pressure) .It is not discharged in the normal natural water level, but the groundwater level rises during the rainy season and the ground water level is higher than the height of the drain pipe of the present invention. When is increased, the groundwater is naturally overflowed by natural law to discharge.

1 is a conceptual diagram of buoyancy acting on the underground building structure.

Figure 2 is a vertical drain pipe installation state of the present invention.

Figure 3 is a state diagram showing the installation height in installing the vertical drainage pipe.

Figure 4 is a state diagram showing the installation interval in installing the vertical drainage pipe.

5 is a plan view showing the installation interval in installing the vertical drainage pipe.

6 is a cross-sectional view of a filter tube as a main part of the present invention.

Figure 7 is a cross-sectional view of another embodiment of the filter tube, which is the main part of the present invention.

Explanation of Reference Numbers

1: vertical drainage pipe 2: filter pipe

2 ': hole 3: inlet tube

4: drain pipe 5: piping

6: upper pipe 6 ': hole

7: building structure 8: nonwoven fabric (filter)

9: nonwoven fabric (filter) 11: foundation slab bottom

12: soil

Drill the drain hole in the bottom of the foundation slab 11, and install the inlet pipe (3) vertically inside the drain hole, the filter pipe (2) installed vertically in the ground (12) is connected to the bottom of the inlet pipe (3) The upper part of the inlet pipe (3) is connected to the pipe (5) and the upper pipe (6), the height of the drain pipe (4) installed in the pipe (5) is characterized in that connected to the height of the usual ground water level (GWL) It is a structure of vertical drainage pipe (1) for preventing buoyancy of underground buildings.

In the filter tube 2 embedded in the ground vertically in the above, a plurality of holes (2 ') are perforated on the outer peripheral surface of the tube, the outer cylinder outer periphery of the hole (2') is perforated can act as a filter The nonwoven fabric 8 and 9 were wrapped in double.

In addition, the upper end of the upper pipe (6) installed on the top of the vertical drainage pipe in consideration of the increase in the inflow underground water so that the upper surface of the water surface 6 'to be in contact with the atmospheric pressure layer.

Hereinafter, the present invention will be described in more detail.

The biggest feature of the vertical drainage pipe 1 of the present invention is that the height of the drainage pipe 4 is set at a position as high as the normal ground water level (GWL). Therefore, the drainage is not made at the normal groundwater level (GWL), and the drainage is made only when the water level rises above the normal groundwater level. In other words, since the height of the drain pipe installed in the vertical drainage pipe is normally installed at the position of the groundwater level, since the groundwater level does not rise above the drainage pipe height in normal times, water is not drained, but As the water level rises, the groundwater rises above the height of the drain pipe, and the water naturally drains.

On the other hand, at the bottom of the vertical drainage pipe, a filter tube 2 having a hole 2 'is inserted vertically into the ground 12 so that groundwater water flows through the hole 2'. The nonwoven fabrics 8 and 9 are double wrapped to act as filters. In this case, the nonwoven fabric used as the filter material should not be blocked by the surrounding soil, and if it has sufficient permeability compared to the surrounding soil, it should be sufficient, but only if the nonwoven fabric has a strong tensile strength and good flexibility to achieve the desired effect. .

In the case where the nonwoven fabric is doubled to surround the filter tube, one layer of nonwoven fabric may be attached to the inside of the through body, and the other layer may be wrapped around the outside of the through body. Hereinafter will be described a system for determining the height and spacing of the vertical drain pipe in the installation of the vertical drain pipe.

In general, the influence factors of buoyancy of underground structure (7) are self-weight (dead load) of building, normal groundwater level in general, groundwater level in critical state of buoyancy, water level considering worst case elevation, field permeability of building subsurface Evaluate from the influencing factors of factor (k). Each influencer is defined as follows.

① Structural Weight (SW) of building: Evaluated by unit dead weight of structure (t / ㎡)

② Permeability coefficient of the ground under the building: Permeability coefficient of the ground evaluated by the ground survey (m / sec)

③ Normal ground water level (GWL): Ground water level obtained from the ground survey (GL-m)

④ Critical Ground Water Level (CGWL): Critical Ground Water Level (CGWL): Groundwater level (GL-m) with the same self-weight of building and working water pressure on the floor

⑤ Worst High Water Level (WHWL) considering worst case water level rise (WHWL): Assumed to be the worst level condition expected from rainy season and disaster (GL ± 0m)

First, the height (H) determination of the vertical drainage pipe is described. In general, the upper end of the vertical drainage pipe is generally determined in preference to the current groundwater level or the upper part so that drainage does not occur normally and drains only when the water level rises. However, after considering the quantity generated at each level, it may be determined by considering the correlation of the horizontal spacing of vertical drainage pipes according to the type of building.

Describing the spacing (d) of the vertical drainage pipe, the working pressure of the bottom slab ground is stable against buoyancy even when the water level (WHWL) rises considering the worst case water level from the geotechnical and hydraulic engineering characteristics. Determine vertical drainage spacing so that vertical drainage can be used. In this case, even if the groundwater level around the structure rises from GWL to become WHWL, the level rise due to the maximum generation of buoyancy generated at the slab bottom between the vertical drainage pipe and the drainage pipe installed inside the building should be smaller than CGWL. The formula is:

Distance from the outside of the building:

Distance between vertical drains:

here , = Spacing between vertical drains (m)

S: depth of CGWL (m)-depth of GWL (m)

k: Permeability coefficient of lower slab ground (m / sec)

By using the above formula, it is possible to determine how many vertical drainage pipes are required for a certain area of the structure.In the above, FS is a safety factor, when the k value is confirmed by the field test, the coefficient is set to 1, and from the general physical properties When using estimates, it is safe to set the coefficient to 3.0 or higher.

As described above, the height and spacing of the vertical drainage pipe can be determined. In this case, when the height of the vertical drainage pipe is lower than the normal groundwater condition, the spacing of the vertical drainage pipe can be widened. When the drain pipe is increased, the gap between the drain pipes and the drain pipe is increased, so the gap between the vertical drain pipes should be examined while adjusting the height of the drain pipe top height from the top surface of the building floor slab.

The vertical drainage pipe of the present invention is a method of reducing buoyancy by installing a drainage pipe that drills a drainage hole at the bottom of the foundation slab and maintains a constant groundwater level, and collects inflowing groundwater flowing into the sump well and drains it by a pump.

However, the vertical drainage pipe of the present invention is a drainage is not made in the normal ground water level (GWL) as described above is that there is a big advantage that the maintenance cost does not occur because the pump amount does not occur.

In addition, when the groundwater level rises above the normal groundwater level as in the rainy season, the groundwater level becomes higher than the height of the drainage pipe, so that the groundwater overflows automatically to prevent the groundwater level.

The present invention as described above can be effectively used when the existing structure is affected by the positive pressure is that the installation is simple and the construction is simple, the overall process management is easy. In addition, it is easy to apply even when there is a large amount of groundwater and difficult to apply other methods, it is a very useful design that can produce a much superior effect compared to the anchor method or general drainage method in consideration of economical efficiency, construction properties, stability.

Claims (3)

Drill the drain hole in the bottom of the foundation slab 11, and install the inlet pipe (3) vertically inside the drain hole, the filter pipe (2) installed vertically in the ground (12) is connected to the bottom of the inlet pipe (3) The pipe 5 and the upper pipe 6 are connected to the top of the inlet pipe 3, but the height of the drain pipe 4 installed at the top of the pipe 5 is connected to the height of the usual ground water level (GWL). The structure of the vertical drainage pipe for preventing buoyancy buried underground buildings. The filter tube (2) embedded in the ground (12) is a plurality of holes (2 ') perforated on the outer peripheral surface of the tube, the outer cylinder outer peripheral surface is punctured A structure of a vertical drainage pipe for preventing buoyancy of underground buildings, characterized in that it is double wrapped with a nonwoven fabric (8) (9) that can act as a filter. The structure of a vertical drainage pipe for preventing buoyancy of an underground building according to claim 1, wherein a hole (6 ') is drilled at an upper end of the upper pipe (6) installed at the top of the vertical drainage pipe (1).