JPH0762428B2 - Construction pillar method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a construction pillar construction method for excavating a hole (hereinafter, referred to as a "construction pillar hole") for burying a utility pole particularly in the soil such as an urban area.

[Conventional technology]

An earth auger drill is usually used for excavating a building pillar hole, but in urban areas where buried objects such as gas pipes and water pipes are laid in a complicated manner, the earth auger drill may cause damage to the buried object. Therefore, it is the current situation that the excavation work is carried out while searching for the buried object by hand digging.

However, since the building pillar hole requires a depth of about 2 to 3 meters, when it is manually dug, it becomes a terraced excavation, which requires a large excavation space, and a large amount of excavated soil appears around the excavated hole. It is necessary to secure some space.
Also, if you hit a buried object in the middle of excavation, you have to change the excavation position and dig again, and the work up to that point will be a waste of work, or you will fill useless buried holes or scrape the pavement part of the urban area. In addition, it will require a great deal of work such as fixing it.

[Problems to be Solved by the Invention]

In recent years, in view of such circumstances, it has become common to carry out radar surveys of buried objects in the ground from the ground before excavation.

This laser exploration method emits electromagnetic waves from the surface of the earth into the soil, and the electromagnetic waves traveling in the soil cause reflection and refraction phenomena in an embedded object with a dielectric constant different from that of the soil. This is a method of detecting the position of an object.

However, with this conventional buried object radar exploration method, it is difficult to perform accurate exploration due to the fact that some buried objects have a permittivity similar to that of soil, and that errors occur as the distance from the surface of the earth increases. It is the current situation.

Therefore, according to such a conventional radar exploration method, if an exploration of the entire underground area is performed from the surface of the earth, and if a tentative exploration result with no buried object is obtained, a drill hole of the final target diameter from the beginning (for example, 450φ) is excavated, but if it hits the buried object, the work of exploring and excavating another position again will be repeated. In addition, excavation using this radar exploration method may cause damage to buried objects such as water pipes and gas pipes in the soil, which is extremely dangerous, and post-processing such as repair work and exploration with incorrect exploration A great waste of labor and time is required to fill the holes.

The present invention has been made in view of such circumstances, and when excavating a building pillar hole, wastefulness of excavation labor can be saved by more accurately determining the presence or absence of an embedded object, and even if a water pipe Alternatively, it is an object of the present invention to provide a building pillar construction method in which even if it hits a buried object such as a gas pipe, there is no fear of damaging the buried object.

[Means for Solving the Problems]

The above problems can be solved by the present invention having the following steps. That is, a primary exploration for investigating the presence or absence of a buried object in the depth direction by a ground radar exploration, a primary excavation for obtaining a small diameter excavation hole to the final depth by hydraulic excavation in the excavated soil, and a borehole radar for the excavation hole Insert an antenna to carry out radar surveys for the presence of buried objects in the circumferential direction of the borehole 2
A construction pillar method characterized by sequentially undergoing secondary exploration and secondary excavation for expanding the excavation hole to the final diameter.

[Action]

The present invention conducts primary excavation in the depth direction and secondary excavation for further excavating the excavated holes after investigating the presence or absence of buried objects in the soil through the above-mentioned primary and secondary radar searches. It is characterized by excavating the building pillar hole by carrying out.

First, in the primary exploration, the presence of buried objects in the depth direction is investigated by ground radar exploration.

Next, the place where a temporary exploration result without a buried object is obtained by the above-mentioned primary exploration is excavated by hydraulic excavation to the final depth (primary excavation). Since this excavation is performed by hydraulic excavation, even if there is a buried object during the excavation due to an error in the exploration, the buried condition can be maintained without damaging the buried object such as the water pipe or the gas pipe.

In addition, the hole formed by this excavation may have a small diameter such that the radar antenna for the borehole can be reliably inserted in the secondary exploration, and even if the hole is filled due to an error in the exploration, it does not require much labor and waste is minimized.

Since the secondary exploration is for radar exploration for the presence or absence of buried objects in the circumferential direction of the hole due to the primary excavation,
In the primary excavation, it is indispensable to excavate to the final depth required for the building columns.

The secondary exploration is performed by inserting a borehole radar antenna into the hole formed by the primary excavation.

According to this secondary radar survey, it is possible to perform a close-up survey in the circumferential direction of the drill hole by the primary excavation, so a much more reliable survey result can be obtained in the ground radar survey.

Then, if the secondary exploration results show that there is no buried object in the circumferential direction of the excavation hole, the excavation hole is enlarged to the final diameter required for the building pillar, thus obtaining the building pillar hole with the predetermined diameter and the predetermined depth. To be

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 (a) and 1 (b) are diagrams showing the steps of exploration and excavation by the building pillar method of the present invention, and a concrete example of excavating a building pillar hole having a final diameter of 450φ and a final depth of 3 m. Show.

First, in FIG. 1 (a), the radar measurement system 2
The electromagnetic wave 2a is emitted from the ground location scheduled to be built by the in the depth direction of the soil 3, and the presence or absence of the buried object in the soil is searched (primary exploration is completed). In this ground radar survey, if a tentative survey result with no buried pipe 4 such as a water pipe or a gas pipe is obtained, the pavement portion 3a is cut with a core cutter (not shown), and is shown in FIG. 1 (b). So that the jet fountain 5
With this, a hydraulic excavation with a diameter of 200φ smaller than the final diameter is excavated to a final depth of 3 m to obtain the excavation hole 6 (primary excavation completed).

Then, as shown in FIG. 1 (c), a pipe 9 is inserted to prevent the soil wall of the excavation hole 6 from collapsing, and this pipe is made of a material that can transmit electromagnetic waves, The borehole radar antenna 8 is inserted and an electromagnetic wave 8a is emitted in the circumferential direction of the excavation hole 6 to perform a buried object search up to a range of about 600φ (secondary search). Then, when an exploration result indicating that there is no buried object in the soil 3 in the circumferential direction of the excavation hole is obtained, the pipe 9 is pulled out from the excavation hole 6, and the 500φ bore cutter 7 is used as shown in FIG. 1 (d). The pavement is expanded, and then, as shown in FIG. 1 (e), the earth auger drill 10 of 450φ is used to excavate the borehole 6 having a depth of 3 m and the building pillar hole 11 Obtain (end of secondary drilling). The building pillar hole 11 thus obtained is formed by a usual method.

〔The invention's effect〕

As described above, according to the building pillar construction method of the present invention, the presence or absence of a buried object in the depth direction is searched by ground radar search, and then the primary drilling is performed to obtain a drilling hole of the final depth required for the building pillar. However, this excavation is due to hydraulic excavation that does not damage the buried object even if it hits the buried object during the excavation. Furthermore, the diameter of the drilled hole makes it possible to insert the borehole radar antenna in the next secondary exploration. Since the diameter is as small as possible, it is possible to safely cope with the unforeseen situation of excavating the relevant location of the buried object, and the effort for primary excavation and hole filling / recovery of the existing situation up to then is minimal. By further conducting a radar survey in the circumferential direction of the drilling hole, a more reliable survey result can be obtained than ground surveying. By expanding the small diameter hole to the final diameter required for the building pillar, It is possible to obtain the subject of Ken pillar holes.

Therefore, much more reliable exploration results can be obtained compared to the conventional excavation method by ground exploration, and it becomes possible to excavate extremely excellent in terms of safety as well, and it is safe and labor-saving especially in urban areas with many dangerous buried objects. It is possible to obtain a building pillar construction method that enables excavation of a building pillar hole.

[Brief description of drawings]

FIGS. 1 (a) to (e) are diagrams showing the steps of exploration and excavation by the building pillar method of the present invention. 2 ... Radar measurement system, 2a ... Electromagnetic waves in the depth direction, 4 ... Buried objects, 5 ... Jet fountain, 6 ... Drilling hole by primary excavation, 7 ... Core cutter, 8 ... Borehole Radar antenna, 8a ... electromagnetic waves in the circumferential direction of the drilling hole, 10 ... Earth auger drill, 11 ... Drilling hole by secondary drilling (building pillar hole)

Claims (1)

[Claims] 1. A building pillar construction method for exploring a predetermined building pillar hole by investigating the presence or absence of an embedded object in the soil, the primary exploration for exploring the presence or absence of an embedded object in the depth direction by ground radar surveying, Primary excavation to obtain a small diameter drilled hole to the final depth by hydraulically drilling in the searched soil, and insert a borehole radar antenna into the drilled hole to perform radar search for the presence or absence of a buried object in the circumferential direction of the drilled hole 2
A construction pillar method characterized by sequentially undergoing secondary exploration and secondary excavation for expanding the excavation hole to the final diameter.