JPH0246387A - Floating preventing method for existing buried pipe due to liquefaction of ground - Google Patents

Abstract

PURPOSE:To prevent a buried pipe from being floated due to liquefaction of the ground at the tie of an earthquake or the like by forming a gate-shaped member with two vertical piles and a beam member, pinching the existing buried pipe with the vertical piles, and allowing lower ends of the vertical piles to reach into a nonliquid layer. CONSTITUTION:A gate-shaped member 10 connected with a beam member 11 such as H-type steel on upper ends of two parallel steel pipe piles 12 is manufactured in advance. The gate-shaped member 10 is pushed by pressure in the direction shown by an arrow P so that the lower ends reach into the ground of a nonliquid layer 13 and the beam member 11 is located nearly at the upper end of the existing buried pipe 14. The existing buried pipe 14 is pinched by gate-shaped members 10 at the preset interval in the extension direction of the existing buried pipe. As a result, no digging work of the ground is required, the pushing work of the gate-shaped members by pressure is performed, the construction in an urban district or the like is facilitated.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a system for installing existing buried pipes that can economically prevent the uplift of existing buried pipes due to ground liquefaction during earthquakes, etc., without the need to excavate the ground. This invention relates to a method for preventing buried pipes from floating up when the ground liquefies.

[Conventional technology]

When an earthquake occurs in sandy ground, sand particles become suspended in the water contained in the sandy ground, and the ground liquefaction occurs, causing the ground to lose its supporting capacity. It occurs especially in sandy ground such as reclaimed land and alluvial land.

Such pipes buried in the ground have a problem in that they are given a large buoyant force by the liquefaction of the ground and float up.

Conventionally, measures to prevent ground liquefaction such as those described above have been used, such as compaction methods, replacement methods, and crushed stone drain methods, which prevent liquefaction itself, but all of these methods are quite expensive in construction costs.

Therefore, as shown in Figs. 3 and 4, below the buried position of the pipe l buried in the loose ground S,
Two piles 6 on each side on the left and right at predetermined intervals l in the length direction.
is driven through a loose ground S into a firm supporting ground R, and a buried pipe 1 is connected to these piles 6 by a cable 3 and supported against buoyancy. Japanese Unexamined Patent Publication No. 59-2195 on ground liquefaction countermeasure construction method
No. 89 inventions have been made, and it is known to be more economical than the conventional ground liquefaction countermeasures.

However, in the construction method of the above-mentioned known invention, the pile material 6 driven into the ground and the buried pipeline 1 are fixed with cables 3, etc., so there is no problem in the case of new construction, but When applying this construction method, it is necessary to excavate the ground to the location of the buried pipe and perform the connection work, and if there is a structure near the buried pipe, the work will be a major loss, so construction in urban areas is not easy. The problem was that it wasn't.

[Purpose of the invention]

The present invention has been made in order to solve the above-mentioned conventional problems, and it is economical because there is no need to excavate the ground for existing buried pipes. The purpose of this invention is to provide a method for preventing floating of water.

[Summary of the invention] In order to achieve the above object, the method of preventing existing buried pipes from floating up during ground liquefaction according to the present invention is to connect the upper ends of vertical pile materials such as two parallel steel pipe piles with H-shaped steel or reinforcing steel. , multiple gate-shaped members connected by welding etc. using finger members such as PC steel rods are manufactured in advance, and the above two vertical pile materials sandwich the existing buried pipe, and the lower ends of these vertical pile materials are made non-liquefied. Each gate-shaped member is press-fitted and installed to a predetermined depth at a predetermined interval in the extending direction of the existing buried pipe so that the finger member reaches the layer and is located almost at the upper end of the existing buried pipe. However, in order to prevent vibration and noise, it is preferable to apply a gate-shaped Yatco or the like to the upper end of each vertical pile material of the concave member and press-fit with a hydraulic press-in machine or the like at the time of press-fitting.

According to the above method, when taking measures to prevent existing buried pipes from floating due to ground liquefaction during an earthquake, there is no need to excavate the ground, and measures to prevent floating can be easily taken.

〔Example〕

The present invention will be described in detail below with reference to the drawings. Fig. 1 is a front sectional view of an embodiment in which the lifting prevention method of the present invention is applied to an existing buried pipe, and Fig. 2 is a cross-sectional view of the construction of Fig. 1. It is a rear side view.

First, the upper ends of two parallel vertical pile members 12 such as steel pipe piles as shown in FIG. 1 are indicated by diagonal lines for convenience.
1, the necessary plurality of gate-shaped members IO connected by welding are manufactured in advance, and these gate-shaped members 10 are connected to the second gate-shaped member IO.
As shown in the figure, the existing buried pipe 1 has been buried in the liquefaction layer A.
4 in the direction shown by the arrow P in FIG. 1 to a predetermined depth.

In this case, the interval H between the two vertical pile members 12 of the gate-shaped member 10 is set to be slightly wider than the outer diameter of the existing buried pipe 14.

In addition, the two vertical piles 12 of each gate-shaped member 10 that have been press-fitted are inserted into the ground of the non-liquefaction layer B at the lower ends of the vertical piles 12, sandwiching the existing buried pipe 14 as shown in FIG. The gate-shaped member 10 is manufactured with dimensions such that the finger member 11 reaches approximately the upper end of the existing buried pipe 14, and is press-fitted to a predetermined depth. Note that if a reinforcing bar, a PC1il rod, or the like is used for the finger member 11, the press-fitting resistance will be reduced and construction can be performed more easily.

At the time of the above-mentioned press-fitting, the gate-shaped Yatco 13 shown in FIG. The gate-shaped member 10 is installed in the liquefaction layer A so that the lower end reaches the inside of the liquefaction layer B, and after installation, the
3 is pulled out, and if necessary, the site of the press-fitting is leveled to complete the installation of the gate-shaped member 10 as shown in Fig. 2, which serves as a measure to prevent floating.

〔Effect of the invention〕

As explained above, according to the method for preventing uplifting during ground liquefaction of the present invention, when taking measures to prevent uplifting of existing buried pipes due to ground liquefaction at the time of an earthquake, etc., excavation work in the ground is prevented. This has the advantage of making construction easier in urban areas, etc., since it is no longer needed and a press-fitting operation is performed to press-fit the gate-shaped member.

In addition, since the gate-shaped member to prevent uplifting is press-fitted using a hydraulic press-in machine, there is an advantage that there is less vibration and noise during work, and it is easy to use even if there is a structure near the existing buried pipe. Work can be done.

[Brief explanation of the drawing]

Figure 1 is a front cross-sectional view of an example in which the lifting prevention method of the present invention is applied to an existing buried pipe, Figure 2 is a side view after the construction of Figure 1, and Figure 3 is a view of a conventional buried pipe. A side view of the ground liquefaction countermeasure construction method, Figure 4 is a front sectional view of Figure 3. DESCRIPTION OF SYMBOLS 10... Gate-shaped member, 11... Finger member, 12... Vertical pile material, 14... Existing buried pipe, A... Liquefaction layer, B...
...Non-liquefaction layer, D...Predetermined interval, P...Press-fitting direction.

Claims (1)

[Claims] A gate-shaped member is made in advance by connecting the upper ends of two parallel vertical piles with a girder member, and the two vertical piles sandwich the existing buried pipe, and the lower ends of the vertical piles become non-liquefied. Ground liquefaction of existing underground pipes by press-fitting each gate-shaped member at a predetermined interval in the extension direction of the existing underground pipe so that it reaches the layer and the girder member is almost at the upper end of the existing underground pipe. How to prevent time from rising.