JPS5930862B2 - Buried piping construction method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a buried piping construction method that prevents uneven settling of pipe bodies when pulling out protective sheet piles during construction of buried piping.

Generally, when constructing underground piping, as shown in the cross-sectional view in Figure 1, protective sheet piles 1, 1 are laid underground with a certain width and at a predetermined location along the pipeline to be buried. After driving to a certain depth, the earth and sand between the sheet piles 1 and 1 is removed to a predetermined depth to create a buried trench 2. After laying the pipe body 3 on the bottom 2a of the buried trench 2 to form a conduit, A construction method is used in which earth and sand is backfilled into the 2nd floor, and then the sheet pile 1.1 is pulled out and removed.

In the above construction method, the sheet piles 1, 1 are driven in to protect the surrounding earth and sand from collapsing when forming the buried trench 2, but regulations require that they be pulled out and removed after the buried piping is constructed. It is mandatory.

However, when the sheet piles 1, 1 are pulled out, a void is created in the ground after being pulled out by the cross-sectional area of the sheet pile and the soil removed by the pulling out, and as a result, the soil moves to fill such a void. The ground sinks.

The amount of ground subsidence mentioned above is calculated as follows.

That is, in the plan explanatory view of FIG. 2A and the side explanatory view of the opening in the figure, the cross-sectional area S of the sheet pile 1 is 5=(Hxt), where the width of the sheet pile is H1 and the thickness is t.

In addition, the gap created after pulling out one set of left and right sheet piles is as follows: Gap per set of sheet piles = SxLx2x (1+α) However, S
: Cross-sectional area of one sheet pile L: Length of the sheet pile in the ground α: Adhesion rate of soil to one sheet pile.

Therefore, the amount of subsidence δ is expressed as.

For example, applying the above formula to a 5p-tr type sheet pile, L: 600CWl, L': 300cn1. H:
40cm, t:10C? 71. αf:1. #=150
Since Crn, the amount of ground subsidence becomes 16 cm.

Such subsidence of the ground inevitably causes subsidence of the buried pipe.Subsidence of the buried pipe does not cause any particular problem if the pipe body and the ground subside uniformly, but this is explained in Figure 3. As shown in the figure, in the part where one end of the pipe 3 is fixed by the pit 4 etc., the pipe 3 buried underground as shown by the dotted line
However, as a result of uneven settlement as shown by the solid line, excessive stress is generated in the pipe body 3a in this part, causing damage.

From the above-mentioned viewpoint, the present invention provides a buried pipe construction method that does not cause uneven settling of the pipe body due to ground subsidence after pulling out the sheet pile. This is done by suspending the pipe laid in the pipe in a horizontal state in advance, and then inserting it into the void on the bottom surface of the pipe, which was created as a result of ground subsidence due to the pulling out of the sheet pile.
This method is characterized in that a fluid solidifying agent is injected and then the suspension of the tube is released.

Next, the present invention will be explained based on examples and drawings.

FIG. 4 shows a plan view of an example of the construction method according to the present invention, and FIG. 5 shows a cross-sectional view of the hanging portion of the tube.

In the drawing, reference numerals 1 and 1 are sheet piles driven into the ground with a predetermined width maintained, and laying the pipe body 3 in the burial trench 2 formed by the sheet piles 1 and 1 is the same as the conventional method. It is.

In this invention, when laying the tube body 3, a hose 4 for injecting a fluid solidifying agent and a hose 5 for air venting are connected to the tube body 3 at predetermined intervals, one end of which is connected to the bottom surface of the tube body 3. Install it in an upright position so that the other end is on the ground, and then lay it.

The hoses 4, 5 have a diameter of, for example, 50 mm in the illustrated embodiment.
As shown in Fig. 4, use a rubber hose with a diameter of about mm, and connect air vent hoses 5, 5, etc. to the opposite side of the tube between the fluid solidifying agent injection hoses 4, 4, etc.・The distance between each hose was 3 to 4 m.

Reference numeral 6 denotes a frame body for suspending pipes, which straddles the sheet piles 1 and 1 and is erected on the ground at appropriate intervals, and includes pillars 6a, 6a, and pillars 6.
It consists of a beam 6b suspended horizontally between the upper ends of 6a and 6a.
A chain block 8 is attached to the beam 6b via a hook 7.

On the other hand, a lifting hook 9 is attached to the upper surface of the pipe body 3 laid in the buried trench 2 at the upright position of the frame body 6, and after the pipe body 3 is laid, the lifting hook 9 is attached to the The wire 8a of the chain block 8 is engaged, and the pipe body 3 is suspended horizontally by the chain block 8.

In the illustrated embodiment, a falling weight hook 10 is attached to the tip of the wire 8a to facilitate engagement and disengagement with the lifting hook 9.

10a is a string for operating the falling weight hook 10.

After the pipe body 3 is in the above-mentioned state, soil 1 is placed in the buried trench 2.
1 is backfilled, and then the sheet piles 1 and 1 are pulled out and removed.

When the sheet piles 1 and 1 are pulled out, the earth and sand move as described above, causing ground subsidence, but as described above, the pipe body 3 is suspended by the chain block 8 on the frame body 6 and kept in a horizontal state. .

Next, as shown in Fig. 6, the end of the hose 4 for injecting a fluid solidifying agent attached to the pipe body 3, which protrudes above the ground, is connected to the pump 12 for injecting concrete to prevent ground subsidence. The pump 1 is inserted into the created gap 13 on the lower surface of the tube body 3.
2, a fluid solidifying agent 14 such as air mortar is injected.

At this time, the air existing in the voids 13 and, if there is groundwater, are also discharged from the air venting hose 5, and the state of injection of the fluid solidifying agent into the voids 13 can be determined from the state of this air discharge. .

After the injection of the fluid solidifying agent 14 into the gap 13 on the lower surface of the tube body 3 is completed as described above, the fluid solidifying agent injection hose 4 and the air venting hose 5 are connected to each other for injection of the fluid solidifying agent 14. While doing so, workers pulled it out from the ground and removed it.

Due to the hardening of the fluid solidifying agent 14 described above, the pipe body 3 is placed in a stable horizontally buried state, so that the lifting hook 9 of the pipe body 3 can be installed by excavating a portion and attaching the lifting hook 9 to the pipe body 3. Remove the falling weight hook 10 attached to the tip of the wire 8a of the chain block 8 that has been fitted, and
The frame body 6 to which is attached is removed.

Next, the excavated area mentioned above will be repaired and the construction work will be completed.

FIG. 1 shows a side view of another embodiment of the flowable solidifying agent injection step in the method of the present invention, and FIG.
It is shown by a cross-sectional view taken along line A.

In this embodiment, a pit 1 to which a pipe body 3 is attached
5, an insertion hole 17 for the fluid solidifying agent injection hose 4 and an insertion hole 18 for the air venting hose 5 are provided at the lower part of the wall 16 of the tube 3.
The fluid solidifying agent injection hose 4 is inserted into the cavity 13 on the lower surface of the tube 3 along the axial direction of the tube 3, and the air purge hose 5 is inserted into the insertion hole 18. put.

Next, from the fluid solidifying agent injection hose 4, the cavity 13 is
While injecting a fluid solidifying agent 14 such as air mortar into the space, the hose 4 is gradually pulled out and moved back, and after the cavity 13 is filled with the fluid solidifying agent, it is pulled out from the insertion hole 11. and remove the force.

The air venting hose 5 is also removed in the same manner.

The following steps are similar to those in the embodiment described above.

- As can be seen from the above explanation, according to the present invention, even if ground subsidence occurs due to the removal of protective sheet piles during construction of buried pipes, the buried pipe body will undergo uneven settlement, and the pipe body will not be damaged. Excessive stress is not generated, pipe bodies can be buried safely and accurately, and it is effective not only against ground subsidence caused by pulling out sheet piles, but also against ground subsidence caused by other causes. , an excellent effect is brought about.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the construction of buried pipes, Figure 2 is an explanatory diagram of the amount of ground subsidence, Figure 3 is an explanatory diagram of uneven settlement of buried pipes, and Figure 4 is an example of the construction method according to the present invention. FIG. 5 is a cross-sectional view showing the hanging portion of the pipe body, FIG. 6 is an explanatory diagram showing the injection state of the fluid solidifying agent, and FIG. 7 is another embodiment of the fluid solidifying agent injection method. FIG. 8 is a sectional view taken along line A--A in FIG. 7. In the drawing, 1...winter board, 2...buried trench, 3...
・Pipe body, 4, 5... Ho, 2. , @...frame body, 7.
... Hook, 8°°° chain block, 9 ... Lifting hook, 10 ... Falling weight hook, 11 ... Earth and sand, 1
2...Pump, 13...Gap, 14...Fluid solidifying agent, 15...Pit, 16...Wall, 17°18
...Insertion hole.

Claims (1)

[Claims] 1 The pipe body is laid in a buried trench formed by sheet piles driven along the pipeline to be buried, and then, after backfilling the buried trench with earth and sand, the sheet pile is pulled out. In the buried piping construction method, when pulling out the sheet pile, the pipe body laid in the buried trench is suspended in a horizontal state in advance, and then the pipe body is suspended as a result of ground subsidence due to the pulling out of the sheet pile. A method of constructing buried piping, which comprises injecting a fluid solidifying agent into the gap on the lower surface of the pipe body, and then releasing the suspension of the pipe body.