JPH07286356A - Method of floatation and settlement preventive construction of underground buried pipe - Google Patents

Abstract

PURPOSE:To prevent the settlement and floatation of a buried pipe by boring a plurality of pairs of boring pits up to a hard ground on both sides of the existing buried pipe, executing a let grout to the pits and around the buried pipe and inserting steel bars into the pits. CONSTITUTION:A plurality of boring pits 11 are bored up to a hard ground 5 while being oppositely faced on both sides of a buried pipe 1 such as a sewerage pipe. The boring pits 11 are impregnated with cement milk while a jet grout is executed to the periphery of the buried pipe 1, and a massive improved body 25 is formed while the buried pipe 1 is borne by a columnar improved body 23. Steel bars 19 are inserted before cement milk is cured, and the buried pipe 1 is reinforced. The steel bars 19 may also be inserted into the pits 11 before the impregnation of cement milk. Even when a liquefaction phenomenon due to land subsidence and an earthquake is generated, the buried pipe 1 is not subject to the effect. Accordingly, the floatation and settlement of the buried pipe can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing floating and subsidence of underground pipes such as underdrain pipes, sewer pipes and gas pipes.

[0002]

[Prior Art] With the increase in population, the development of industrial society, the promotion of urbanization, etc., three-dimensional use of space is advancing, and nowadays, such as railway tunnels, road tunnels, subways, etc. as transportation-related, and civic life-related. Underground space is used as an extension of aboveground space in various fields such as gas, sewer, lifelines such as underground power lines.

[0003] In the past, when laying an underdrain, a sewer pipe, a gas pipe, etc. underground, careful attention has been paid, for example, by reinforcing the laying ground so as to maintain a proper pipeline.

[0004]

However, when the ground subsides due to the pumping of groundwater or the liquefaction of the ground occurs due to the occurrence of an earthquake, these underground conduits, sewer pipes, etc. buried underground may sink or There is a risk that it will rise and be destroyed.

Therefore, when newly laying these buried pipes, as described above, reinforcement work is applied to the laying ground to take measures to prevent the buried pipes from sinking or rising. The reality is that almost no seed measures have been taken.

[0006] When these existing buried pipes sink or float and are ruptured, conventionally, the buried pipes are dug up from the surface of the earth and laid again, but the construction cost increases because the road is cut and cut. However, there is a demand for measures to prevent floating and subsidence of existing underground pipes.

The present invention has been devised in view of the above circumstances, and an object thereof is to provide a method for preventing floating and subsidence of an existing underground buried pipe against ground subsidence, ground liquefaction and the like.

[0008]

[Means for Solving the Problems] In order to achieve such an object, the method for preventing the floating and subsidence of an underground buried pipe according to claim 1 is arranged so that both sides of an existing underground buried pipe are sandwiched with the buried pipe interposed therebetween. The boring holes that make up are drilled at regular intervals over the hard ground below the ground in which the buried pipe is buried, and jet grouting is performed from inside the boring hole around the buried pipe to harden between the pair of boring holes. After forming the jet grout band of the material, a steel wire or a steel rod is inserted into the boring hole.

The invention according to claim 2 is based on claim 1.
In the method for preventing the floating and subsidence of underground buried pipes, after the hardening of the hardened material, the upper part of the steel wire or the steel rod is fixed on the ground surface part through the supporting member.

Further, in the method for preventing the floating and subsidence of an underground buried pipe according to claim 3, the buried pipe is buried on both sides of the existing underground buried pipe with a pair of boring holes sandwiching the buried pipe. After drilling holes at a constant interval over the hard ground below the ground, inserting a steel wire or steel rod into the boring hole, and then performing a jet grouting from inside the boring hole around the buried pipe to form a pair of boring holes. A jet grout band of a hardening material is formed on the surface of the hardened material.
In the method for preventing the floating and subsidence of underground buried pipes, after the hardening of the hardened material, the upper part of the steel wire or the steel rod is fixed on the ground surface part through the supporting member.

[0011]

According to the first aspect of the present invention, a pair of boring holes sandwiching the existing buried pipe is formed on both sides of the existing underground buried pipe extending over the hard ground below the ground where the buried pipe is buried. After drilling at regular intervals, perform jet grouting from the inside of the boring hole around the buried pipe to form a jet grouting zone of hardened material between the pair of boring holes, and then install a steel wire or steel rod in the boring hole. Insert and cure the hardener,
Further, as in the invention according to claim 3, boring holes forming a pair sandwiching the buried pipe are formed on both sides of the existing underground buried pipe over the hard ground below the ground where the buried pipe is buried. After drilling holes at regular intervals and inserting a steel wire or steel rod into the boring hole, perform jet grouting around the buried pipe from inside the boring hole to form a jet grouting band of hardened material between the pair of boring holes. Then, between the columnar improved bodies which are paired and supported by the hard ground, the block-shaped improved bodies in which the jet grout bands are hardened are formed with a constant interval.

Even if the ground subsides due to the pumping of groundwater or a liquefaction phenomenon occurs due to the occurrence of an earthquake, the existing buried pipes buried underground still have a columnar improvement body and a blocky improvement body. It will be supported by the hard ground.

Further, when the upper portion of the steel wire or the steel rod is fixed by the supporting member at the surface portion as in the inventions according to claims 2 and 4,
The columnar improved body is firmly supported by the hard ground and the ground surface portion.

Therefore, according to the invention construction methods of the second and fourth aspects, when the liquefaction phenomenon occurs due to the occurrence of an earthquake, the burying is more reliably carried out than the invention construction methods of the first and third aspects. The floating of the pipe will be prevented.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 to 8 show a first embodiment of the inventive method according to claim 1 and claim 2, wherein in FIG. 1, 1 is an existing sewer pipe embedded in a relatively soft ground 3. In a hard ground such as a viscosity layer, a water pipe 7 and a gas pipe 9 are buried in the ground 3 in parallel with the sewer pipe 1 near the surface of the earth.

In this embodiment, first, a plurality of casing pipes are sequentially connected according to the drilling depth, and the drilling bit mounted at the tip of the casing pipe is as shown by the solid lines in FIGS. 1 and 2. To
Boring holes 11 forming a pair on both sides of the sewer pipe 1, that is, at symmetrical positions with the sewer pipe 1 sandwiched, are drilled vertically to the hard ground 5 at regular intervals.

The boring hole 11 may have any drilling means. Normally, the drilling water is injected into the casing pipe to drill the ground 3 with a drilling bit. The boring hole 11 may be provided by using jet water.

Then, the casing pipe is filled with cement milk, and the method is disclosed in JP-A-54-47318 and JP-B-56.
No. 29049 or a well-known jet grout method as shown in FIGS.
Insert the injection rod 13 into the inside, and then pull out the casing pipe and rotate the injection rod 13 to inject the jet 15 of cement milk (hardening material) between the boring holes 11 to lower the sewer pipe 1 from the upper part to the lower part. Jet grouting zone 1 that encircles the sewer pipe 1
Form 7. By performing the jet grouting in this way, the cement milk S is filled in the boring hole 11 as shown in FIGS. 3 and 4.

In this case, jet grouting may be performed from the lower part of the sewer pipe 1 toward the upper part to form the jet grout zone 17 surrounding the sewer pipe 1. And
After the end of the jet grout, the injection rod 13 as shown in FIG.
, And if necessary, the cement milk S is replenished and filled in the boring holes 11 to the upper part, and then a steel rod 19 or a steel wire is inserted into each boring hole 11 as shown in FIG. Then, after the cement milk S is hardened, if the upper portion of the steel rod 19 is fixed to the ground surface portion 21 by a support plate or the like not shown, the cement milk S in the boring hole 11 is hardened as shown in FIGS. 7 and 8. The columnar improved body 23 formed as a result is firmly supported by the hard ground 5 and the ground surface portion 21, and the jet grout band 17 is provided between the columnar improved body 23 supported by the ground surface portion 21 and the hard ground 5 in a pair. The lump-improved body 25, which has been cured, will be formed at regular intervals.

Since this embodiment is constructed in this way, even if the ground 3 sinks due to the pumping of groundwater, or even if the ground 3 liquefies due to the occurrence of an earthquake, the sewers buried underground. The pipe 1 will be supported by the hard ground 5 via the columnar improving body 23 and the block improving body 25.

Therefore, when the invention method according to the present embodiment is applied, even if the ground 3 sinks due to the pumping of ground water or the ground 3 is liquefied due to the occurrence of an earthquake, it is buried in the ground 3. It is possible to reliably prevent the existing sewer pipe 1 from sinking and floating, and its construction does not need to dig up the sewer pipe 1 from the surface portion 21, and is substantially the same as the construction of earth anchors that are widely used in the past. Since it can be performed by various means, it has an advantage that it can be constructed extremely easily and inexpensively.

9 to 14 show a second embodiment of the inventive method according to claims 1 and 2. In this embodiment, the boring hole is changed in the drilling direction in place of the first embodiment. It is a thing.

That is, this embodiment is constructed mainly when the water pipe and the gas pipe are not buried above the sewer pipe 1 which is buried in the ground 3, and first, a plurality of casing pipes are sequentially connected, The boring hole 27 attached to the tip of the sewer pipe 1 forms a pair of boring holes 27 on both sides of the sewer pipe 1, that is, at symmetrical positions with the sewer pipe 1 in between, as shown by the solid lines in FIGS. 9 and 10. The holes are drilled at regular intervals up to the hard ground 5 by intersecting with each other. Incidentally, also in this embodiment, the boring hole 27 may be drilled by any means.

Next, as shown in FIGS. 11 and 12, the pair of boring holes 27 is filled with cement milk to insert the injection rod 13, and the casing pipe is pulled up to rotate the injection rod 13. Boring hole 27
In the meantime, a jet 15 of cement milk is jetted to perform jet grout from the upper part to the lower part of the sewer pipe 1 to form a jet grout zone 29 surrounding the sewer pipe 1. By performing the jet grouting in this way, the cement milk S is filled in the boring hole 27 as shown in FIG.

Also in this embodiment, jet grouting is performed from the lower part to the upper part of the sewer pipe 1 to make the sewer pipe 1
You may form the jet grout zone 29 surrounding this.
Then, after the jet grout is completed, the injection rod 13 is pulled up, and in some cases, the cement milk S is replenished and filled to the upper portion in the same way as in the above-mentioned first embodiment, and then, in each of the boring holes 27. Insert the steel rod 19. Then, after the cement milk S is hardened, the ground surface portion 2
When the upper portion of the steel rod 19 is fixed by the support plate in 1, the columnar improvement bodies 31 formed by hardening the cement milk S in the boring hole 27 are hard ground 5 and the ground surface portion 21 as shown in FIGS. 13 and 14. A columnar improved body 3 that is strongly supported by and is supported by the ground surface portion 21 and the hard ground 5 in pairs.
During the period 1, the lump improving body 33 in which the jet grout zone 29 is hardened is formed at regular intervals.

Since this embodiment is constructed in this way, even if the ground 3 sinks due to the pumping of groundwater, or even if the ground 3 liquefies due to the occurrence of an earthquake, the sewers buried underground The pipe 1 will be supported by the hard ground 5 via the columnar improving body 31 and the block improving body 33.

Therefore, even if the invention method according to the present embodiment is applied, even if the ground 3 sinks due to the pumping of groundwater or the ground 3 is liquefied due to the occurrence of an earthquake, It is possible to reliably prevent sinking and floating of the existing buried sewer pipe 1, and the construction thereof does not require excavation of the sewer pipe 1 from the ground surface portion 21. By means substantially similar to the construction of a conventional earth anchor. Since it can be performed, it has an advantage that it can be constructed extremely easily and inexpensively.

In the first and second embodiments, the pair of boring holes 11 and 27 are provided at symmetrical positions with the sewer pipe 1 in between, as shown by the solid lines in FIGS. 2 and 10. However, the boring holes 11 and 27 forming a pair as shown by the chain double-dashed lines in FIGS. 2 and 10 may be provided with some displacement depending on the ground 3 and surrounding conditions.

In each of the above embodiments, the boring hole 1
After the cement milk S filled in the Nos. 1 and 27 was hardened, the upper part of the steel rod 19 was fixed by the support plate or the like at the ground surface portion 21, but this work may be omitted. However, if the upper portion of the steel rod 19 is fixed by the support plate or the like at the ground surface portion 21 in this manner, the columnar improvement bodies 23 and 31 are firmly supported by the hard ground 5 and the ground surface portion 21 as described above. It is preferable as a measure for preventing the sewer pipe 1 from floating against the liquefaction phenomenon of the ground 3.

Further, although the above-mentioned embodiments have explained the method of preventing the subsidence and floating of existing sewer pipes buried underground, the method of the present invention is not limited to sewer pipes, but also underground conduits, gas pipes, and other underground pipes. Of course, it can be widely used as a measure to prevent subsidence and floating of pipes.

In addition, in each of the above-described embodiments, jet grout is performed from inside the boring holes 11 and 27 around the sewer pipe 1 to form a pair of boring holes 11 and 27 of cement milk S between the pair of boring holes 11 and 27. After forming the holes, the steel rod 19 was inserted into the boring holes 11 and 27, but after boring the boring holes 11 and 27 as in the invented method according to claims 3 to 4, first, the boring holes are formed. Insert the steel rod 19 into 11, 27, then sewer pipe 1
A jet grout is formed around the boring holes 11 and 27 to form a jet grout zone 17 and 29 between the pair of boring holes 11 and 27. After the cement milk S is hardened, the steel rod 19 is formed on the surface portion 21.
The upper part of may be fixed via a support plate.

Therefore, the intended purpose can be achieved by the embodiments of the invention method as well as the above-mentioned embodiments.

[0033]

As described above, according to the method of the invention according to each claim, even if the ground subsides due to the pumping of groundwater or the ground liquefaction occurs due to the occurrence of an earthquake, It is possible to prevent subsidence and floating of existing underground pipes such as underground conduits and sewer pipes that are buried underground.
There is no need to excavate a buried pipe from the surface of the ground, and the construction can be performed by means substantially similar to the construction of the earth anchor that has been widely constructed in the past. Therefore, there is an advantage that construction can be performed extremely easily and inexpensively.

The invention construction methods according to claims 2 and 4 have the advantage of being able to prevent the underground pipe from floating more reliably than the invention construction methods according to claims 1 and 3. Have.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the ground in which a boring hole is drilled by the first embodiment of the inventive method according to claim 1 and claim 2.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a cross-sectional view of the ground showing a state in which an injection rod is inserted into a boring hole and jet grouting is started.

FIG. 4 is a sectional view of the ground showing a method for forming a jet grout zone.

FIG. 5 is a cross-sectional view of the ground showing a state where the injection rod is pulled up after the end of jet grout.

FIG. 6 is a cross-sectional view of the ground showing a state where a steel rod is inserted into a boring hole.

FIG. 7 is a cross-sectional view of the ground showing a state in which the existing sewer pipe is supported on the hard ground by the columnar improved body and the block improved body.

8 is a sectional view taken along line VIII-VIII of FIG.

FIG. 9 is a cross-sectional view of the ground with boring holes drilled by the second embodiment of the inventive method according to claim 1 and claim 2.

10 is a cross-sectional view taken along line XX of FIG.

FIG. 11 is a cross-sectional view of the ground showing a state in which the injection rod is inserted into the boring hole and the jet grout is started.

FIG. 12 is a cross-sectional view of the ground showing a method for forming a jet grout zone.

FIG. 13 is a cross-sectional view of the ground showing a state in which the sewer pipe is supported on the hard ground by the columnar improved body and the block improved body.

14 is a sectional view taken along line XIV-XIV in FIG.

[Explanation of symbols]

 1 Sewer pipe 3 Ground 5 Hard ground 11,27 Boring hole 13 Injection rod 15 Jet 17,29 Jet grout zone 19 Steel rod 23,31 Columnar improvement 25,33 Bulk improvement S S cement milk

Claims (4)

[Claims] 1. A boring hole that forms a pair with the buried pipe sandwiched on both sides of an existing underground buried pipe is drilled at regular intervals over a hard ground below the ground where the buried pipe is buried, Underground, characterized by inserting a steel wire or steel rod into the boring hole after forming a jet grout band of hardened material between the pair of boring holes by jet grouting from the inside of the boring hole around the buried pipe. Method to prevent floating and subsidence of buried pipes. 2. The method for preventing floating and subsidence of an underground buried pipe according to claim 1, wherein after hardening of the hardened material, the upper portion of the steel wire or steel rod is fixed at the surface of the ground through a supporting member. 3. A boring hole, which is paired with the buried pipe interposed therebetween, is formed on both sides of an existing underground buried pipe at regular intervals over a hard ground below the ground where the buried pipe is buried, After inserting a steel wire or steel rod into the boring hole, perform jet grouting from inside the boring hole around the buried pipe to form a jet grout zone of hardened material between the paired boring holes. Method to prevent floating and subsidence of buried pipes. 4. The method for preventing floating and subsidence of an underground buried pipe according to claim 3, characterized in that, after hardening of the hardened material, the upper part of the steel wire or steel bar is fixed at the surface of the ground through a supporting member.