JPH04131429A - Underground structure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to an underground structure that can prevent damage such as uplift and subsidence due to liquefaction of the ground.

"Conventional technology and its problems" As is well known, disasters occur in which the ground liquefies during earthquakes, causing structures to rise or sink.As a countermeasure, sand compaction methods, vibroflotation methods, etc. are being used. Although soil compaction is widely practiced, these methods inevitably generate vibration and noise, making it difficult to implement, especially in urban areas. Also,
Other methods that can be implemented in urban areas include the gravel drain method and the method of solidifying the ground with cement, but these methods are expensive and do not necessarily produce sufficient results.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an underground structure that can effectively prevent damages such as uplift and subsidence caused by liquefaction of the ground.

"Means for Solving the Problems" The underground structure of the present invention is provided with a water-stop wall that reaches an impermeable layer from the ground surface around a framework provided underground, and a wall surface and a bottom surface of the framework. It is characterized by having a permeable layer formed by filling the periphery with gravel, crushed stone, etc. in a permeable manner.

"Function" In the underground structure of the present invention, the permeable layer promotes drainage from around the structure, and the water-stop wall provided around the structure prevents groundwater from flowing in. , liquefaction at the bottom of the building structure is less likely to occur, and
Even if liquefaction were to occur, the increase in water pressure would be suppressed to a low level, and major damage would be prevented.

"Embodiment" An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In these figures, reference numeral 1 indicates a reinforced concrete frame installed in the ground 2 that is likely to cause liquefaction and is used as a common ditch, and 3 indicates an impermeable layer (clay layer) 4 from the ground surface.
5 is a water-permeable layer filled with gravel, crushed stone, etc., provided around the wall and bottom of the frame 1.

As mentioned above, in an underground structure having a structure in which a permeable layer 5 is provided around the frame 1 and a water stop wall 3.3 that reaches the impermeable layer 4 is provided on the outside thereof, the liquid in the ground 2 is This can effectively prevent damage such as lifting or sinking of the frame 1 due to oxidation.

In other words, since the permeable layer 5 promotes drainage from the ground 2 around the frame 1, liquefaction of the ground 2 around the frame 1 is less likely to occur, and even if liquefaction occurs, the rise in water pressure is low. In addition, the frame 1 is a water stop wall 3
, 3 prevents groundwater from flowing in from the outside of the water-stop wall 3.3. Therefore, if the frame 1 rises even slightly, the water pressure will drop sharply and it will rise further. This will prevent any major damage from occurring.

Also, if the rigidity of the water-stop wall 3.3 is sufficiently high, the shear deformation applied to the ground 2 during an earthquake will be reduced by the rigidity of the water-stop wall 3.3, and this will also cause liquefaction of the ground 2. There is also the advantage that it becomes difficult, and in this respect, it is desirable to sufficiently increase the rigidity of the water-stop walls 3, 3. Note that the above-mentioned water-stopping walls 3, 3 may of course be provided with the main purpose of water-stopping, but if they reach the impermeable layer 4, it is also possible to use temporary mountain stoppers.

As described above, the underground structure of the above embodiment can effectively prevent damage caused by liquefaction of the ground 2, and does not require soil improvement work such as compaction of the ground 2. Therefore, it does not generate noise or vibration, unlike when compaction methods such as sand compaction method or vibroflotation method are implemented, and it is also advantageous in terms of construction costs.

In addition, as shown in FIGS. 3 and 4, the water stop walls 3 and 3 in the above embodiment are connected to each other by another water stop wall I! which is perpendicular to them. 3', and in this way, the rigidity of the entire water-stopping wall can be further increased, liquefaction of the ground can be further prevented, and the stability of the frame can be increased. Further, although the above embodiment is applied to a public ditch, it can also be applied to a general underground structure (for example, an underground water tank) having a rectangular planar shape as shown in FIG.
Needless to say, the method can be applied in exactly the same way to the basement of a building having an underground floor.

"Effects of the Invention" As explained in detail above, the present invention provides a water-stop wall that reaches from the ground surface to an impermeable layer around a framework installed underground, and also provides water-stop walls around a wall and bottom surface of the framework. Since the structure has a permeable layer filled with gravel, crushed stone, etc. in a permeable manner, the permeable layer promotes drainage from around the structure, making it difficult for liquefaction to occur, and also preventing liquefaction from occurring. ;However, the increase in water pressure can be suppressed to a low level, and
Since the building frame is surrounded by a water-stop wall, groundwater will not flow in from the outside, so damage caused by liquefaction can be effectively prevented.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment in which the present invention is applied to an underground structure used as a common ditch, with Figure 1 being a side sectional view and Figure wc2 being a plan view. 3 and 4 show another embodiment in which the present invention is applied to a structure used as a common ditch, with FIG. 3 being a side sectional view and FIG. 4 being a plan view. FIG. 5 is a plan view showing an embodiment when applied to a general underground structure. 1...Structure, 2...Ground, 3...
...Water-stop wall, 4... Impermeable layer, 5...
Permeable layer.

Claims (1)

[Claims] An underground structure that can prevent damage such as uplift or subsidence caused by liquefaction of the ground, and is equipped with a water-stop wall that reaches from the ground surface to an impermeable layer around the framework installed underground, and An underground structure characterized by having a water-permeable layer formed by filling gravel, crushed stone, etc. in a water-permeable manner around the walls and bottom of the structure.