JPH0821177A - Method and equipment for investigating ground soil under large-scale structure - Google Patents

Abstract

PURPOSE:To prevent the collapse, etc., of a structure by excavating an investigating pit while being curved toward a section just under the outer circumference of the large-scale structure such as a crude oil tank from the outer circumference of the large-scale structure and accurately investigating the quality of soil and penetration resistance at a specified place. CONSTITUTION:An investigating pit is excavated while being curved toward a section just under a center by an excavator 10 consisting of an outer tube 1, inner tubes, etc. The investigating pit is dug out up to a specified place, the inner tubes 2 are extracted, a soil material sampler or a penetrameter measuring the penetration resistance of the ground is mounted at a front end section, and inserted into the outer tube 1 and a sampling or measurement is conducted. The quality of the ground just under the structure 12 is examined accurately, thus preventing the generation, etc., of a liquefaction phenomenon at the time of an earthquake. Accordingly, investigation can be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for investigating the soil soil directly under a large structure such as an existing oil storage tank.

[0002]

2. Description of the Related Art The foundation ground directly under a large structure such as an existing oil storage tank undergoes secular changes such as deformation, subsidence, and destruction due to groundwater infiltration, ground compression, expansion, weathering, earthquakes and other vibrations. . In particular, regarding the liquefaction of the ground and the slippage of the foundation that occur during an earthquake, ensuring the safety of the above large structures,
In order to take preventive measures from the aspect of management, it is necessary to carry out the ground soil investigation directly below the above. In a structure such as a small-capacity oil storage tank, since the diameter of the oil storage tank is small, vertical boring is performed from the outer ground of the oil storage tank, and the soil properties of the ground can be known by soil soil investigation.

However, in the foundation ground directly under a large-scale structure such as an existing oil storage tank having a diameter of several tens of meters, if the vertical boring from the peripheral ground as described above is performed, the ground directly under the structure is I cannot know the properties of the ground.

In the prior art, since excavation is performed just below a large structure, the bit mounted on the tip of the inner pipe is eccentric with respect to the inner wall of the outer pipe by the outer pipe and the inner pipe which are curved in the longitudinal direction. However, the technique of excavating in a curved shape has already been put to practical use (for example, Japanese Patent Publication No. 4-64396).

However, although the technique described above excavates while curving directly under a large structure, a technique for investigating the soil soil directly under the large structure has not been provided yet.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to improve the soil condition directly below a large structure without adversely affecting a large structure such as an existing oil storage tank. It is an object to provide a ground survey method and device under a large structure that can be surveyed or monitored.

[0007]

In order to achieve the above-mentioned object, the present invention provides a method of investigating the ground soil condition directly under a large structure, in which a large-scale structure is provided directly below the outer circumference ground of the large structure. The ground is excavated and propelled by using an excavator having an outer pipe curved in the longitudinal direction and a bit at the tip and an inner pipe curved in the longitudinal direction, and then when the tip reaches a predetermined position, Pull out the pipe to the ground and replace the bit at the tip with a sampling tool that collects a soil sample,
Then, the inner pipe fitted with the sampling tool is again inserted into the ground, and the soil sample is sampled by press-fitting the sampling tool at the predetermined position.

The present invention also replaces the bit at the tip with a penetrometer for measuring the penetration resistance of the ground, and then
It is characterized in that the inner pipe fitted with the penetrometer is inserted into the ground again, and the penetration resistance of the ground is measured by the penetration of the penetrometer at the predetermined position.

Further, according to the present invention, an excavator for excavating and propelling the ground by curving the ground from the outer ground of the large structure to directly below the large structure is provided with an outer pipe curved in the longitudinal direction and a bit at the tip. It comprises an inner tube that is provided and curved in the longitudinal direction, and when the tip reaches a predetermined position, the inner tube can be pulled out to the ground and the bit at the tip can be replaced with a sampling tool for collecting a soil sample. It is characterized in that the inner pipe fitted with the sampling tool is inserted into the ground, and the sampling tool collects a soil sample by press fitting at the predetermined position.

[0010]

Operation: The excavator excavates the ground by curving the ground directly below the large structure to form a survey hole, and when it reaches a predetermined position for soil investigation, pull out the inner pipe of the excavator and remove the tip. After exchanging with a sampling tool or a penetrometer, the sample is inserted again into the survey hole, and the soil sample is sampled or the penetration resistance is measured at the predetermined position. By repeating the above-mentioned operation, it is possible to reliably investigate the ground soil at a plurality of predetermined positions immediately below the large structure.

[0011]

FIG. 1 shows an embodiment of the present invention. FIG. 1 shows a curved outer tube 1, a curved inner tube 2, a drive unit 3 provided at the tip of the inner tube 2, and a rotating portion 3 provided at the tip of the drive unit 3.
The excavator 10 includes a, a bit 4 provided at the tip of the rotating portion 3a, and a bit 5 provided in the circumferential direction of the rotating portion 3a.

The rotating portion 3a of the drive unit 3 is driven by projecting it from the tip of the outer pipe 1, and the inner pipe 2 and the outer pipe 1 are propelled while excavating the ground by the bits 4 and 5. This propulsion is carried out by press fitting from the ground, and reaches a predetermined position while adding a relatively short curved tube. At this time, a plurality of points can be selected as the predetermined position.

In FIG. 2, the existing large-scale structure 12 is erected on the ground 14, and when excavating the ground 14 from the outer peripheral ground of the large-scale structure 12 to directly below the structure 12, the excavation is performed. When the tool 10 is excavated and propelled to obtain a curved survey hole and the bit 4 of the rotating portion 3a, which is the tip of the inner pipe 2, reaches a predetermined position for soil investigation, the drive unit 3 is moved. The inner tube 2 is stopped, the inner tube 2 is pulled out to the ground, and the drive unit 2 is replaced.

3 and 4, the drive unit 3 of the inner tube 2 is replaced with a sampling tool 20 for sampling a soil sample,
When the inner tube 2 with 0 attached to the coupling 2a is moved to the inside of the outer tube 1 and the sampling tool 20 arrives by the predetermined time, the sampling tool 20 is inserted into the ground 14 by a not-shown pressurizing means so that Collect soil samples. Then, the inner pipe 2 is pulled out to the ground, the sampling tool 20 is detached from the coupling 2a, the sample is taken out from the sampling tool 20, and a soil investigation test is performed.

Subsequently, the drive unit 3 is attached to the inner pipe 2, and the excavator 10 is again excavated and propelled to a new predetermined position.

A thin wall open sampler is suitable as the sampling tool 20, and a thin wall tube 22 is used.
The soil sample is taken in. 21 is a fixture 23 provided on the opposite side of the thin wall tube 22
The threaded portion of the tube 22 is detachably attached to the coupling 2a, and the tube 22 is attachable to and detachable from the attachment portion 23 with a screw. Reference numeral 24 is a relief valve provided inside the fixture 23. The gas in the tube 22 is compressed when the soil sample is taken in, and when the pressure exceeds a certain pressure, the valve 24 is opened to discharge the thin wall tube. The collection of the sample in 22 is made smooth, and the property of the soil sample is prevented from becoming unstable.

In the embodiment shown in FIG. 5, a penetrometer 30 is attached to the tip of the inner pipe 2 to measure the penetration resistance of the ground 14, and the coupling 2b and the penetrometer 3 are used.
Except 0, it is the same as the embodiment shown in FIGS.

A cone pertrometer is preferably used as the penetrometer 30 so that it can be penetrated into the ground 14 by a pressurizing means (not shown) so that the data such as the pushing force and the pushing amount can be received on the ground by using the detecting means. Has been done.

It is also possible to embed a piezometer or other observation instrument at a predetermined position on the ground 14 and observe or monitor the ground on the ground 14 for a long period of time.

In this way, by conducting a soil investigation or monitoring of the ground immediately below the large structure, it is possible to know whether the ground is liquefied or contains a large amount of water, and the countermeasure can be taken to deal with the large structure. It is possible to prevent things from collapsing.

[0021]

Industrial Applicability When the soil investigation method and device for a large structure under a large structure according to the present invention is used to conduct a soil investigation, a large area can be widely spread at predetermined points immediately below the large structure without adversely affecting the large structure. It is possible to reliably investigate the ground soil quality.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an apparatus suitable for implementing the present invention.

FIG. 2 is an explanatory diagram of ground excavation by the excavator.

FIG. 3 is an explanatory view of sampling with the sampling tool.

FIG. 4 is a detailed view of sampling with the sampling tool.

FIG. 5 is an explanatory diagram of penetration resistance measurement by the penetrometer.

[Explanation of symbols]

 1 Outer pipe 2 Inner pipe 4,5 bit 10 Excavator 12 Large structure 20 Sampling tool 30 Penetrometer

Claims (4)

[Claims] 1. A method for investigating the soil soil immediately below a large structure, comprising an outer pipe curved in the longitudinal direction from the outer ground of the large structure to a position directly below the large structure, and a bit at the tip. The ground is excavated and propelled by using an excavator that becomes an inner pipe curved in the longitudinal direction, and then the inner pipe is pulled out to the ground when the tip reaches a predetermined position, and a bit at the tip is taken as a soil sample. Replacing with a sampling tool, and then inserting the sampling tool-equipped inner pipe into the ground again and pressing the sampling tool at the above-mentioned predetermined position to collect a soil sample. Survey method. 2. The bit at the tip is replaced with a penetrometer for measuring penetration resistance of the ground, and then the inner pipe equipped with the penetrometer is re-inserted into the ground to penetrate the ground by penetrometer penetration at the predetermined position. The soil soil investigation method under a large structure according to claim 1, wherein the resistance is measured. 3. An excavator for excavating and propelling the ground by curving the ground from the outer ground of a large structure to directly below the large structure is provided with an outer pipe curved in the longitudinal direction and a bit at the tip and in the longitudinal direction. The inner tube is made of a curved inner tube, and when the tip reaches a predetermined position, the inner tube can be pulled out to the ground and the bit at the tip can be replaced with a sampling tool for collecting a soil sample. An apparatus for ground soil investigation under a large structure, characterized in that the inner pipe fitted with is inserted into the ground and the sampling tool collects a soil sample by press fitting at the above-mentioned predetermined position. 4. The bit at the tip is replaced with a penetrometer for measuring penetration resistance of the ground, and an inner pipe equipped with the penetrometer is inserted into the ground to allow the penetrometer to penetrate the penetration resistance of the ground at the predetermined position. The device for ground soil investigation under a large structure according to claim 3, which is measured.