JPS5833337B2 - How to bury the pipe - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for burying pipes underground.

It is well known that underground pipes deform due to earth pressure, and the following relationship exists between the earth pressure W and the amount of deformation σ of the pipe.

KWR"' EI=0.061eR In the above, E is the Young's modulus of the pipe, ■ is the moment of inertia of the pipe wall per unit length of the pipe, R is the radius of the pipe, K is the coefficient due to the support angle of the foundation, e is the passive earth pressure coefficient on both sides of the pipe.

As is clear from the above, the amount of deformation of the pipe decreases as the passive earth pressure coefficient e increases.

Conventionally, in order to prevent deformation of pipes due to tonosho, the backfilling soil on both sides of the pipes was compacted as much as possible to reduce the above-mentioned passive earth pressure coefficient e.
is increasing.

However, even if the backfill soil is compacted, when pulling out the sheet pile,
Part of the earth and sand on both sides of the pipe flows into the hole where the sheet pile was pulled out, causing the compacted earth and sand on both sides of the pipe to become loose, so it is often impossible to increase the passive earth pressure coefficient.

For this reason, the applicant proposed mixing cement with the backfilling soil on both sides of the pipe, and after backfilling the entire management groove, waiting for the cement-mixed soil to harden before pulling out the sheet pile. , Cement may be washed away by the spring water at spring locations, making it impossible to sufficiently increase the above-mentioned passive earth pressure coefficient e.

This disadvantage is unavoidable because even if cement is not mixed into the backfilling soil on both sides of the pipe, some of the soil will be washed away.

The method of burying a pipe according to the present invention is a method that allows a pipe to be buried stably even in a spring water location, by laying cobblestones or crushed stones on the bottom of a management trench, and placing the pipes on the paving stones and on both sides of the bottom of the trench. The feature is that a water-blocking sheet is laid across the trench, and then a pipe is placed in the trench, and then the trench is backfilled with earth and sand.

The present invention will be explained below with reference to the drawings.

In the figure, D is an excavated groove, and sheet piles P are driven along both sides of the groove.

To bury a pipe according to the present invention, first, cobblestones or crushed stones 1 are laid on the bottom of the trench, and then water-blocking sheets 2 are laid over the paving stones 1 and across both sides of the trench bottom.

A hard vinyl sheet, a polyethylene sheet, or the like is used for this water-blocking sheet 2.

After laying the water-shielding sheet 2, base sand 3 is laid down to a thickness of 30 to 50 α, and thoroughly hardened with a rammer, a tacho rod, etc.

If necessary, 2 to 10 times of cement may be mixed into this basic sand 3.

After constructing the foundation, pipe A is installed in accordance with the usual method, earth and sand 4, 4 are poured into both sides of pipe A, and the earth and sand are sufficiently hardened.

Cement can be mixed into these top sands 4, 4 as well, if necessary, as described above.

Further, it is preferable that the upper end 21 of the above-described water-blocking sheet 2 be arranged at a level slightly higher than the filling level of the earth and sand 4 on both sides of the pipe.

After filling with the top sand 4, 4, the upper part of the pipe A is backfilled with high-quality soil or sand 5, and after this backfilling, the sheet pile P is pulled out, thereby completing the construction.

In this case, since the water-blocking sheet 2 is interposed as a partition between the hole in the trail of the sheet pile P and the earth and sand 4 on both sides of the pipe, the earth and sand 4 do not flow into the hole in the trail of the sheet pile P. Sediment 4,
There is no way that the tenacity of 4 will be loosened.

In addition, when mixing cement into the earth and sand 4, 4, it is desirable to wait for this cement to harden (it may be left to stand for 2 to 3 days after the completion of the above-mentioned backfilling), and then pull out the sheet pile P.

As described above, the method for burying a pipe according to the present invention is to lay cobblestones or crushed stones on the bottom of the management installation trench, lay a water-blocking sheet on top of that, and then bury the pipe. Even if spring water occurs locally in the ditch, this spring water is dispersed by the layer of cobblestones or crushed stones, and the impermeable sheet prevents water from seeping into the earth and sand near the pipe.

Therefore, it is possible to effectively prevent the earth and sand near the pipe from being washed away by spring water, and the compacted state can be maintained at the initial stage, so the passive earth pressure coefficient e mentioned above can be sufficiently increased. This makes it possible to minimize deformation of buried pipes due to earth and sand.

[Brief explanation of the drawing]

FIG. 1 is an explanatory drawing for illustrating the present invention. In the figure, A is a pipe, D is a management groove, 1 is a boulder or crushed stone, 2 is a water-blocking sheet, and 3, 4.4, and 5 are earth and sand.

Claims (1)

[Claims] 1 Lay cobblestones or crushed stones on the bottom of the management facility trench, lay a water-blocking sheet over the paving stones and across both sides of the bottom of the trench, and then install a pipe in the trench, and then A pipe burying method characterized by backfilling a trench with earth and sand.