JPH01239219A - Anitiseismic structure of waterway road for shielding water - 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] This invention relates to an earthquake-resistant reinforcement structure for a dug road in ground that is likely to liquefy.

[Conventional technology]

Conventional excavation roads, especially excavation roads close to embankments,
Earthquake-resistant construction methods for dug roads built on slopes include:
There are many compaction methods, and in recent years, the crushed stone drain method [Taniro et al.:
Analysis of the application of gravel drains as a measure against liquefaction on moat roads, 41st Annual Academic Conference of the Japan Society of Civil Engineers, November 1986] has also been attempted. The background to this is that the former applies soft ground countermeasures directly to ground that includes sandy soil layers, while the latter was born out of research into recent earthquake damage, particularly the liquefaction phenomenon of sandy ground and sandy soil layers. In addition to these methods, consolidation methods using cement milk, etc. are also being considered.

[Problem to be solved by the invention]

These conventional construction methods can be expected to have a considerable seismic resistance effect when the adjacent part is an embankment, or when applied to a vast area including directly beneath the embankment, but in the case of an existing excavated road, for example, As shown in FIG. 11, the improvement area has to be constructed only directly under the excavated road 1, and the improvement area is extremely limited. In addition, in the figure, 3 is a liquefied layer such as sandy ground, 13
is a ground improvement section using compaction or crushed stone drains.

As a result, an increase in excess pore water pressure during an earthquake in the surrounding liquefied layer 3 is transmitted to these improved portions 13, and the entire excavated road 1 is lifted up.

Further, at the same time as this uplifting phenomenon, the embankment or the slope portion sinks, and the liquefied layer 3 exhibits lateral fluid behavior, thereby moving in the horizontal direction.

Even when the area adjacent to the excavated road 1 is on a natural slope, the conventional construction method shows the same results as in the case of the existing construction described above, and every time an earthquake occurs, a large amount of cost is required for road repair, slope repair, etc. .

This invention aims to solve the above-mentioned problems.

[Means for Solving the Problems] An overview of the present invention will be described below using reference numerals in the drawings corresponding to the embodiments.

The earthquake-resistant structure of the dug road of this invention has sheet pile walls 2 on both sides of the dug road 1, which have both water-stopping and drainage properties, and thereby block water in the liquefaction layer 3, which is a sandy soil layer. ,
In addition to reducing the excess pore water pressure in the liquefaction layer 3 that occurs during an earthquake, it also blocks the propagation of excess pore water pressure from the surrounding sandy soil layer, and the strength and rigidity of the sheet pile wall 2 prevents the adjacent embankment. This prevents the lateral flow behavior of the liquefied layer from the slopes and slopes, and prevents the excavated road l from lifting up and moving horizontally in the event of an earthquake.

Therefore, in the present invention, at least some of the sheet piles constituting the sheet pile wall 2 have a hollow part in the longitudinal direction, and have a perforated part in which a large number of small holes opening into the liquefied layer 3 are formed. A perforated sheet pile 2a is used. By providing the perforated portion only on one side of the sheet pile wall 2, the water-stopping properties of the sheet pile wall 2 can be maintained, and by placing the perforated portions of adjacent perforated sheet piles 2a on different sides, both sides of the sheet pile wall 2 can be maintained. Excess pore water can be drained from the

As the perforated sheet pile 2a, for example, as shown in FIGS. 6 and 7, a flange 2O of a steel sheet pile 20 having a substantially groove-shaped cross section is used.
A steel plate 21 is welded between b, and the web 20 of the steel sheet pile 20 is
A gap is formed in the longitudinal direction of the steel sheet pile 21 between the steel sheet pile 20 and the steel sheet pile 21, and a large number of small holes 22 are provided in at least one of the steel sheet pile 20 main body and the steel sheet pile 21 (Japanese Patent Application No. 62-280422
As shown in FIG. 8 and FIG. 9, steel pipe sheet piles 30 with a large number of small holes 31 provided on one side can be used.

[For production]

The earthquake-resistant structure of a dug road according to the present invention is such that sheet pile walls 2 made of perforated sheet piles 2a or including perforated sheet piles 2a are cast on both sides of the dug road 1, and adjacent embankments, adjacent slopes, and the lower side of the dug road 1. Since it is installed so as to penetrate the sandy soil layer that spreads through the liquefaction layer 3 made of sandy ground, underground water can be forcibly discharged by applying vibrations during pouring. The ground around the sheet pile 2 can be compacted, and the generation of excessive pore water pressure in the event of an earthquake can be suppressed.
Moreover, due to its water-stopping property, it is possible to block the propagation of excessive pore water pressure in the liquefied N3 around the cut road 1 and prevent the cut road 1 from floating.

Furthermore, by appropriately selecting the cross section and embedment of the sheet piles constituting the sheet pile wall 2, it is possible to prevent the liquefaction layer 3 from lateral fluid behavior and prevent the horizontal movement of the cut road l.

〔Example〕 Next, the illustrated embodiment will be described.

FIGS. 1 and 2 show an embodiment suitable for an existing excavated road.

In the example shown in Figure 1, perforated sheet piles 2a are installed on both sides of an excavated road 1. By suppressing the water pressure near 2a and blocking the propagation of water pressure with the sheet pile wall 2, it is possible to reduce the uplift force U0 caused by excess pore water pressure during an earthquake that acts on the excavated road 1, and to remove the uplift force F caused by seepage hydraulic force. , safety factor against uplift of the excavated road 1 where: W: Dead weight of the excavated road Q: Vertical friction force U on the side wall of the excavated road: Hydrostatic buoyancy Uo: Uplift pressure due to excess pore water pressure during an earthquake F: Due to seepage water Lift pressure can be increased significantly.

On the other hand, since there is an embankment or a natural slope 4, in the event of an earthquake, the liquefied layer 3 directly under it is pushed out in the direction of the excavated road 1, causing the embankment or natural slope 4 to sink and the excavated road 1 to move horizontally, as shown in the figure. , the ground may swell on the right side of the cut road 1, but this can also be sufficiently prevented by considering the cross-sectional sideness of the perforated sheet pile 2a.

In the example shown in FIG. 2, as a further measure against this horizontal movement, earth anchors 5 are installed in the direction of embankment or natural slope 4 at appropriate pitches.

Figures 3 and 4 show an embodiment suitable for a newly constructed excavated road.

In the example shown in Fig. 3, the purpose of use of the perforated sheet pile 2a is the same as in the above case, but since it is a new installation, perforated horizontal tie material 6 is appropriately placed under it before installing the cut road l. The perforated sheet piles 2a are provided at pitches, and the perforated sheet piles 2a separated by the cut road 1 are connected to each other. As a result, the perforated sheet pile 2a and the perforated horizontal tie material 6 form a rigid frame structure, which exhibits sufficient resistance against the above-mentioned horizontal movement, and also suppresses the rise in excess pore water pressure directly under the excavated road I. Therefore, disasters caused by earthquakes can be almost completely prevented. In addition, perforated horizontal connecting material 6
is a steel pipe, a rectangular pipe, etc. having the same structure as the perforated sheet pile 2a shown in FIGS. 6 to 9.

The example shown in Fig. 4 uses crushed stone pine doors and crushed stone columns 8 that provide a drainage function in place of the perforated horizontal tie members 6 in the example shown in Fig. 3, and is similar to the embodiment shown in Fig. 2 to prevent horizontal movement. , earth anchor 5 is used.

Figure 5 shows an embankment or natural slope 4 adjacent to the excavation road 1.
This is an example of a case where there is no .

In this case, there is no horizontal movement in the cut road 1, so
In order to completely prevent floating, crushed stone pine doors, crushed stone pillars 8, and perforated sheet piles 2a are used together.

6 to 9 show examples of perforated sheet piles 2a used in the present invention.

In the example shown in FIG. 6, a perforated plate 21 with a large number of small holes 22 is attached so as to connect the flanges 2Ob of the conventional steel sheet pile 20, and the perforated plate 21 is connected to the main body of the steel sheet pile 20 and the perforated plate 21. A perforated sheet pile 2a is constructed by filling the entire enclosed drainage area with a filter material 23 that prevents the intrusion of ground particles and backfill sand particles. Perforated sheet pile 2 via joint
In the state where A is connected, the water in the liquefaction layer 3 can be drained from both sides of the sheet pile wall 2, and the water-stopping property of the sheet pile joint can block the propagation of seepage water and excess pore water pressure. .

The one shown in Figure 7 is different from the one shown in Figure 6 above,
A filter 24 made of metal or synthetic resin is attached to the entire back surface of the perforated plate 21, and most of the drainage area surrounded by the main body of the steel sheet pile 20 and the perforated plate with filter 21 is hollow, and the filter material 23 is It has higher drainage capacity than a filled type.

In FIGS. 6 and 7, 20c indicates a joint portion, and 25 indicates a welded portion.

The perforated sheet pile 2a shown in FIGS. 8 and 9 is a joint 30a of a conventionally used steel pipe sheet pile 30.

A large number of small holes 31 are formed on one side of the center line connecting 30b.
A filter 32 made of metal or synthetic resin is attached to the inner surface of the steel pipe sheet pile 30. By connecting the steel pipe sheet piles 30 so that the surfaces having the small holes 31 alternate to form the sheet pile wall 2, it is possible to provide both a drainage function and a water stop function. Joint 30a and joint 30b
By filling the area surrounded by bagged mortar 33, water-tightness can be ensured.

In addition, these perforated sheet piles 2a may be used discretely for every several sheet piles in the sheet pile wall 2. When these perforated sheet piles 2a are used on both sides of the excavated road 1, they can be used as earth retaining works during temporary construction, and they can also be used as earth retaining works during temporary construction.
It can also be used as formwork or formwork support for side walls. At this time, as a countermeasure against uneven settlement of the excavated road 1,
As shown in Fig. 10, a bituminous agent or resin agent 11 for reducing friction is applied without making small holes in the area where the concrete contacts the sheet pile wall 2, and a joint material 10 is installed at the cap concrete 9 position of the sheet pile wall 2. Methods such as doing this can be adopted.

In the figure, reference numeral 12 denotes a member that holds the bituminous agent or resin agent 11.

In addition, when the perforated sheet pile 2a does not touch the cut road 1, this can be dealt with by backfilling the space between the sheet pile wall 2 and the cut road 1 with crushed stone.

Although not shown, the water in the perforated sheet pile 2a is discharged by
This is possible by installing piping inside the cap concrete 9 at the top of the sheet pile wall 2 and connecting it to the drainage ditch of the excavated road 1.

As described above, the water in the liquefaction layer 3 is reliably stopped and drained by the perforated sheet pile 2a, thereby preventing the excavated road l from floating up and uneven settlement.

[Effects of the Invention] The earthquake-resistant structure of the excavated road of this invention is different from conventional earthquake-resistant construction methods by focusing on the behavior and action of water in the liquefaction layer during an earthquake.
Since perforated sheet piles with water-stopping and drainage functions are installed on both sides of the excavated road, the rise in excess pore water pressure within the liquefaction layer that occurs during an earthquake can be suppressed through natural drainage, and the excavated road It can completely block the propagation of excess pore water pressure from the outside and prevent water from penetrating.

In addition, since the rigidity of the perforated sheet pile itself can be selected arbitrarily, it is possible to resist horizontal forces acting on the excavated road from the embankment or natural slope side with the perforated sheet pile.
It also has the effect of preventing horizontal movement of the cut road.

[Brief explanation of the drawing]

FIGS. 1 to 5 are vertical sectional views showing different embodiments of the present invention, FIGS. 6 to 8 are perspective views showing different embodiments of the perforated sheet pile according to the present invention, and FIG. 9 is a perspective view showing different embodiments of the perforated sheet pile according to the present invention. FIG. 8 is a plan view, FIG. 10 is a vertical sectional view showing an embodiment in which measures are taken against uneven settlement, and FIG. 11 is a vertical sectional view of a conventional example. l... Digged road, 2... Sheet pile wall, 2a... Perforated sheet pile, 3... Liquefaction layer, 4... Embankment or natural slope, 5... Earth anchor, 6... Perforated horizontal tie material, 7... Crushed stone mat, 8... Crushed stone column, 9... Cap concrete, 10... Joint material, 11... Bituminous agent or resin agent, 12... Receiver 13... Ground improvement section, 20... Steel sheet pile, 21... Perforated plate, 22...
Small hole, 23... Filter material, 24... Filter, 25... Welded part, 30... Steel pipe sheet pile, 31...
Small hole, 32... filter, 33... mortar

Claims (4)

[Claims] (1) On both sides of the excavated road constructed on the ground with a liquefaction layer, a sheet pile wall with water-stopping properties made of continuous sheet piles is installed, and at least some of the sheet piles constituting the sheet pile wall are An earthquake-resistant structure for a dug road characterized by using a perforated sheet pile having a hollow part in the direction and having a perforated part on one side of the sheet pile wall with a large number of small holes opening into the liquefaction layer. . (2) The perforated sheet piles separated by the excavated road are connected by a perforated horizontal tie material having a hollow part in the longitudinal direction and having a perforated part with a large number of small holes opening into the liquefaction layer. The earthquake-resistant structure of a dug road according to claim 1, which is connected. (3) The earthquake-resistant structure of a dug road according to claim 1, wherein crushed stone mats and crushed stone pillars are installed directly below the dug road between the perforated sheet piles that separate the dug road. (4) The earthquake-resistant structure of a dug road according to claim 1, wherein a part of the sheet pile wall including the perforated sheet pile in contact with the dug road is coated with a bituminous agent or a resin agent.