JP2739317B2 - Measurement control type ground sampling method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an apparatus and a method for collecting a ground sample, and collects a sample required for geotechnical engineering in a predetermined length at a time. It is intended to prevent the sample from falling off by preventing outflow of the sample and facilitating the root cutting of the sample, and to collect a sample without disturbing. [Prior Art] Conventionally, in sampling of soft ground, a pipe with a cutting shoe at the tip is pressed into the ground to collect the sample. However, in the case of a ground which is difficult to press, a cutting shoe as shown in FIG. A sampling device is used in which an inner pipe (11) provided at the tip (10) and an outer pipe (3) provided with a bit (4) at the tip are provided. When this sampling device is used, circulating fluid is sent from the gap between the inner pipe (11) and the outer pipe (3) (flow indicated by an arrow in the figure), and the surrounding ground is excavated with the bit (4). By leading the tip of 10) ahead of the bit (4) surface by L as a protruding length, the fluid prevents the ground sample (25) taken into the inner tube (11) from flowing out. However, the harder the ground, the more difficult it is to press it into the ground unless the protruding length of the shoe is reduced. Therefore, the length of the protrusion of the shoe is determined on the ground on the assumption of the hardness of the ground, and the sampling is performed after setting in advance. This method is widely used as a Denison sampler. In this method, there is a problem that when the hardness of the ground is not suitable, when the hardness of the ground changes, the press-fit cannot be performed, or the sample flows out. Therefore, a device has been devised such that a spring is inserted between the inner pipe head, which is the upper end face of the inner pipe, and the outer pipe head, which is the upper end face of the outer pipe, so that the protrusion length of the shoe is automatically adjusted according to the hardness of the ground. Have been. However, even in this case, the application range was narrow because the spring constant of the spring incorporated in the sample collection device was constant. Therefore, as in Utility Model Registration No. 1411322, a spring is inserted into the air chamber, and after adjusting this air pressure in advance, it can be locked and the sampling rate can be changed to expand the range of applicable ground. Is now available. [Problems to be Solved by the Invention] The method of collecting a ground sample by a multi-tube type sampling device such as a double tube or a triple tube type has been improved as described above, although many methods have been devised. The result is not known until the device is lifted to the ground and the state of the sample is not known.During sample collection, the length of the protruding shoe, the pressure applied to the shoe, and the sample are collected normally, At present, it is not possible for the operator to know about Therefore, if the information can be appropriately controlled while being monitored on the ground, the sampling of the sample is ensured, and the know-how related to the sampling by such a method is easily accumulated. Further, a method has been devised in which after a predetermined sample length has been collected, the shoe is pulled from the bit surface by the latch mechanism to operate the spring basket type catcher (Jpn.
No. 27866), there is no device capable of freely controlling the protrusion length or the amount of pull-in of the shoe with respect to the bit surface during sampling. [Means for Solving the Problems] In view of the above, the present invention has been developed as a result of various studies, a ground sampling method and an apparatus which have solved these problems. That is, the method of the present invention involves excavating the ground at the tip of an outer pipe provided at the lower end of a boring rod lowered to the bottom of a boring hole drilled in the ground, and further digging the ground with the tip of an inner pipe provided inside the outer pipe. In the method of cutting the ground sample into the inner tube by cutting the inner tube, the pressure is transmitted to the piston connected to the upper portion of the inner tube in the cylinder chamber fixed to the outer tube by an uncompressed liquid pressurized by air pressure. The load acting on the cutting shoe at the tip of the tube is detected by the above air pressure,
And controlling the air pressure to adjust the protruding length of the cutting shoe indicated by the liquid level of the incompressible liquid, and furthermore, the liquid filled in the inner tube pushed out by the ground sample taken into the inner tube. The method is characterized in that the volume of a sample taken out into the inner pipe is measured based on the level of the liquid which is led out to the ground. Further, the apparatus of the present invention fixes the upper part of an outer pipe in which an inner pipe provided with a cutting shoe at the tip is fixed to the lower end of a boring rod lowered to the bottom of a boring hole drilled in the ground. In a device that excavates the ground with a bit provided at the tip and simultaneously cuts the ground with a cutting shoe and takes the ground sample into the inner tube, a piston that slides up and down integrally with the outer tube by connecting it to the inner tube A measuring instrument that fixes a cylinder with a built-in, extends a communication path of an incompressible liquid that pressurizes the upper surface of the piston to the ground, and can measure a protruding length of a cutting shoe at a liquid level in the path. And a pneumatic source for applying pressurized air to the liquid surface and a pressure gauge for measuring the pressure of the pressurized air, and further controlling the pressure to move the piston through the incompressible liquid. By Adjust the protrusion length of the setting shoe, fill the space formed by the inside of the inner tube and the top surface of the ground sample with liquid, drill a path communicating with the space on the ground, and place the path in the path. A volume meter capable of measuring the volume of the ground sample taken into the inner tube at the liquid level is provided. [Operation] In this way, instead of the conventional spring for adjusting the extension of the cutting shoe, this was replaced with an incompressible hydraulic piston type such as water or oil, and the fluid transmission pipe was drawn to the ground. The purpose of this is to enable appropriate control while monitoring the pressing force acting on the shoe on the ground equipment and the protrusion length of the shoe.Furthermore, when a sample of a predetermined length is collected, the tip of the shoe is bit-faced. This is because the root can be easily cut by turning the bit and excavating it after drawing inward. In the conventional method, when the sample enters the sample collection device, the fluid in the device is discharged from the top of the device by the volume, but a pipe is connected to the discharge hole, and this is pulled out to the ground. The connection to the volume meter was made so that during the sampling operation, it was possible to monitor whether the sample was collected normally or was flowing out. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a measurement-controlled ground sampling apparatus according to the present invention, in which the left side shows the state where the shoe is at the maximum from the bit surface, and the right side shows the state where the shoe is most retracted. The upper surface of the outer tube head (2) is connected to the tip of a boring rod (1) set in a boring machine (not shown), and the boring rod (1) is lowered to the bottom of the boring hole. A pressure input and a rotational force are applied to the rod (1), and this is transmitted to the bit (4) via the outer pipe (3) fixed to the lower portion of the outer pipe head (2) to cut the ground. The cutting chips are press-fitted from the ground via a boring rod, ejected from the tip of the bit, and discharged together with the circulating fluid discharged to the ground through the outside of the outer tube. In addition, a cylinder (5) is fixed in the upper part in the outer pipe (3), and a center pipe (6) is provided in the center in the vertical direction,
The inner pipe movable transmission pipe (8) that slides up and down along the outer peripheral surface and passes through a bearing housing (7) provided on the lower end face.
Was provided with an annular piston (9). The inner pipe movable transmission pipe (8) extends the cylinder (5) downward along the center pipe (6), and has a cutting shoe (1) at the lower end.
The inner tube head (1), which is the upper end surface of the inner tube (11) formed with (0)
2), the center pipe (6) in which the inner pipe (11) rises as the piston (9) rises enters the inner pipe (11) from the upper part to the lower part. . Accordingly, the piston (9) is moved into the cylinder (5) by introducing an incompressible liquid such as pressurized liquid through the pressure hose (14) into the pressure chamber (13) above the piston (9) in the cylinder (5). A pressing force is applied to the lower end of (5) to apply a rotational force and press force to the boring rod (1), and only the press force is applied to the non-rotating cutting shoe (10) for the bearing housing (7).
And the shoe (10) pushes down the ground to take the ground sample into the sample storage tube (15) provided inside the inner tube (11). Furthermore, the pressure hose (14) is installed on the ground and connected to the cutting shoe extension length measurement room (16), which is a measuring instrument that can measure the extension length of the cutting shoe (10) based on the liquid level inside. The compressed air is supplied from a pneumatic source (17) to the liquid level inside the shoe, and the pressure is controlled by a pressure regulator (18).
The pressure applied to 0) and the protrusion length of the shoe (10) can be adjusted. In other words, the pressure acting on the shoe (10) is a pressure gauge (19), and the protruding length of the shoe (10) can be read from the liquid level using the staff attached to the cutting shoe protruding length measuring instrument (16). it can. The lower chamber of the cylinder (5) is filled with oil. When the piston (9) is lowered, the oil returns into the flexible chamber (21) through the return liquid passage (20). The water pressure in the borehole acts on this chamber (21), and when the pressure gauge (19) is set to zero, the piston (9)
The upper and lower pressures are almost balanced. Sampling is performed by setting the pressure acting on the shoe (10) by the pressure regulator (18) and pushing the ground off with the shoe (10) while excavating with the bit (4) at the tip of the outer tube (3). However, when the sample enters the sample storage tube (15), the water filled in the space formed by the inside of the inner tube (11) and the upper surface of the ground sample has a volume equivalent to the volume of the sample taken in. Water is extruded from the space, passes through the center pipe (6), and is guided through a drain hose (22) to a sampling length measuring chamber (23) which is a volume meter capable of measuring the volume,
The length of the sample taken into the inner pipe (11) can be measured by reading the water surface height with a staff. During sampling, the protrusion length of the shoe (10) will be finely adjusted by the spring coefficient indicated on the pressure gauge (19).
When the hard ground is encountered, the gauge pressure of the compressed air rises and the shoe (10), ie, the inner pipe (11), gradually enters the inside of the outer pipe (3). By doing so, the shoe (10) is further inserted inside to collect a sample. Conversely, if the ground softens and the sample flows out due to the circulating fluid, the water level in the sampling length measurement chamber (23) does not rise. By making the length longer, the outflow of the sample can be prevented. After taking a sample of a predetermined length into the sample storage tube,
Since the air pressure is released by the pressure regulator (18) and the pressure of the shoe (10) is reduced to near zero, the shoe (10) enters the outer pipe (3) as shown in the right side of FIG. The sample near the tip of the shoe (10) flows out, becomes thin, and the root of the sample is easily cut off. In this state, when the valve (24) provided in the middle of the drainage hose (22) is closed and the sample collecting device is pulled up from the boring hole, a vacuum force acts on the upper surface of the sample to prevent the sample from falling off. [Effects of the Invention] As described above, according to the present invention, it is possible to control the protrusion length of the shoe and the spring coefficient for adjusting the protrusion length while monitoring the sample, and to monitor the state of collecting the sample on the ground. The ability to do so has made it possible for even relatively unskilled operators to perform sampling that previously required long experience and advanced technology. In addition, a remarkable effect is exhibited, such as less dropping of the sample.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing an embodiment of a ground sample collecting apparatus according to the present invention, and FIG. 2 is a side sectional view showing a state where a ground sample is being collected. 1 ... boring rod 2 ... outer tube head 3 ... outer tube 4 ... bit 5 ... cylinder 6 ... center pipe 7 ... bearing housing 8 ... inner tube movable transmission tube 9 ... annular piston 10 ... cutting Shoe 11 ... Inner tube 12 ... Inner tube head 13 ... Pressure chamber 14 ... Pressure hose 15 ... Sample storage tube 16 ... Cutting shoe protruding length measuring chamber 17 ... Pneumatic pressure source 18 ... Pressure controller 19 Pressure gauge 20 Return liquid passage 21 Flexible chamber 22 Drain hose 23 Sampling length measuring chamber 24 Valve 25 Ground sample

Claims (1)

(57) [Claims] The ground is excavated at the tip of an outer pipe provided at the lower end of a boring rod lowered to the bottom of a boring hole drilled in the ground, and the ground is cut with the tip of an inner pipe provided inside the outer pipe. In the method of taking the ground sample inside the pipe, the pressure is transmitted to the piston connected to the upper part of the inner pipe in the cylinder chamber fixed to the outer pipe by the uncompressed liquid pressurized by air pressure, and it is transmitted to the cutting shoe at the tip of the inner pipe. The working load is detected by the air pressure, and the air pressure is controlled to adjust the protrusion length of the cutting shoe indicated by the liquid level of the incompressible liquid, and further extruded by the ground sample taken into the inner pipe. Measurement-controlled ground sampling, characterized in that the liquid filled in the inner pipe is led out to the ground and the volume of the sample taken into the inner pipe is measured based on the liquid level. Law. 2. At the lower end of the boring rod lowered to the bottom of the boring hole drilled in the ground, the upper part of the outer pipe with the inner pipe provided with a cutting shoe at the tip is fixed, and the bit provided at the tip of the outer pipe is fixed. In a device that excavates the ground and simultaneously cuts the ground with a cutting shoe and takes the ground sample into the inner tube, a cylinder with a piston that is connected to the inner tube and slides up and down integrally with the outer tube is used. A communication path for an incompressible liquid that is fixed and pressurizes the upper surface of the piston is extended on the ground, and a measuring meter capable of measuring a protruding length of a cutting shoe at a liquid level is provided in the path; A pneumatic source for applying pressurized air to the surface and a pressure gauge for measuring the pressure of the pressurized air are provided, and further, the pressure is controlled to move the piston through the incompressible liquid, thereby cutting the cutting shoe. Adjusting the margin length, filling the space formed by the inner tube interior and the ground sample upper surface with liquid, drilling a path communicating with the space on the ground, and setting the liquid level in the path A measurement-controlled ground sampling apparatus, comprising a volume meter capable of measuring the volume of a ground sample taken into an inner pipe.