JPH039249B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] This invention relates to a ground investigation and measurement method that investigates the soil condition while penetrating a sensor into the ground without vibration or noise, and after burying the sensor, measures the behavior and displacement of the ground. be. [Conventional technology and problems] The ground is composed of air, water, and soil particles.
Ground conditions change over time due to human and natural actions. Such changes in the ground over time can cause landslides and the collapse of mountain retaining walls during civil engineering work, and it is necessary to measure ground behavior in order to predict these changes. Current methods of measuring ground behavior generally involve installing various types of sensors independently in boreholes, but in order to improve analysis accuracy, it is necessary to conduct ground surveys again, and these There were problems such as not only increasing time and labor, but also a large amount of expense, and it was difficult to obtain many measuring points. Therefore, there is currently a need for a proposal for a measurement method that can reliably measure changes in the ground over time. [Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a sensor for observing the dynamics of the ground in a measuring pipe housed in the outer pipe, and an opening at one end of the outer pipe. Pressure fluid is ejected into the ground through the middle pipe inserted into the measurement pipe while rotating the pile tip and outer pipe installed in the measurement pipe, and the outer pipe penetrates the ground with a vertical load, and the depth and rotation at the time of penetration are In addition to measuring the torque, load current value, rotational speed, and pressure fluid ejection pressure, the outer pipe is removed after penetration and the dynamics of the ground is measured using the sensor installed in the measurement pipe. [Function] Various sensors are installed inside the composite body of a measurement tube with a porous tube inside the composite body that has flexibility and water permeability, and a stake tip is attached to the tip of the outer tube housing this measurement tube and inserted into the porous tube. With the hollow body connected to the pile tip, the outer pipe is rotated to penetrate into the ground, and the penetration conditions at this time are memorized. After penetration, the outer tube and hollow body are extracted, and sensors inside the composite body left underground detect earth pressure, water pressure, strain, etc. in the ground, and the sensor is lowered into the porous tube to measure the water level. By combining the measured values with the measured data at the time of penetration, changes in the ground and soil quality can be known. Regarding the measurement records at the time of the above-mentioned penetration, there are the following achievements. In the method of penetrating piles into the ground, the jetting of pressurized water and the rotation of the piles penetrate the piles without noise or vibration, and the various conditions at the time of penetration, such as penetration depth, rotational load, and number of rotations over time, are The present applicants proposed a method of measuring and recording the pressure fluid ejected at the tip of the pile in Japanese Patent Publication No. 31603/1983. With the above construction method, by measuring the penetration conditions, it is possible to confirm that each pile has penetrated into the supporting layer, and by compiling data from all piles, it is possible to calculate or measure the total cumulative bearing capacity. There are advantages. The huge amount of measured values in the above track record contributes to the analysis of this construction method. [Embodiments] Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. Figure 1 shows the underground survey and measurement process.
The figure is an enlarged cross-sectional view of the underground penetrating state, and FIG. 4 shows the rotary pushing device using the same vertical load. The outer pipe 1 that penetrates into the ground has a pile tip 2 at the lower end opening.
is arranged, and the measurement tube 3 is housed inside. The pile tip 2 is formed into an inverted conical shape that closes the lower end opening of the outer tube 1, has a plurality of digging vanes 4 fixed to its outer circumferential surface, and opens at a sharp end along the axis. A nozzle hole 5 is provided, and a hollow body, that is, a hollow rod 6 inserted into the measuring tube 3, is detachably connected by a threaded structure or the like.
The pile tip 2 and the outer tube 1 are rotated while blowing out pressurized air or water from the nozzle hole 5, and the outer tube 1 is penetrated into the ground. The measurement tube 3 includes a composite body 7 having flexibility and water permeability, such as a sponge, formed into a cylindrical shape with an outer diameter that fits inside the outer tube 1, and a porous material forming the core of this composite body 7. The hollow rod 6 penetrates the inside of the porous pipe 8 in the axial direction and connects to the pile tip 2.
is connected with. Various sensors are incorporated into the composite body 7 of the measurement tube 3. These sensors include, for example, a vibration meter 9, a strain gauge 10, an earth pressure gauge 11, and a water pressure gauge 12 housed in the composite body 7, and a water level gauge 13 is lowered into the porous pipe 8. There is. The measured values of each of these sensors are input to and recorded in the measurement recording device 14 placed on the ground. The rotary pushing device shown in FIG.
The hollow rod 6, whose upper end is engaged with the output shaft of the excavation device 17, is rotated to rotate the outer pipe 1 together with the pile tip 2, and penetrate into the ground. There is. This penetrating device is provided with a detection device so that a soil survey can be conducted when the outer tube 1 is penetrated. These detection devices are detailed in Japanese Patent Publication No. 54-31603, and include a penetration depth detection device K of the outer tube 1, and a current detection device N consisting of a current transformer and the like for detecting the load current of the excavation device 17. , a rotation speed detection device P such as a tachometer provided on the excavation device 17, and a pressure detection device Q such as a pressure transducer connected to a hollow rod connected to the pile tip 2, each of the detection devices K,
Each of N, P, and Q transmits the measured value to the recorder M by an electric signal, and the recorder M displays each measurement signal on an indicator or on a recording paper 18 as shown in FIG. In addition to recording with a pen recorder, etc., it is also digitized and recorded on a floppy disk. The construction method of the present invention using the above-mentioned devices includes providing the measurement tube 3 inside the outer tube 1, and the porous tube 8 of the measurement tube 3.
The lower end female threaded part of the hollow rod 6 inserted inside is screwed into the male threaded cylinder of the pile tip 2 to integrate the outer tube 1, the pile tip 2 and the hollow rod 6, and then the outer tube is inserted using a rotary pushing device as shown in Fig. 4. Outer pipe 1 is placed on the ground where construction is to be carried out while supporting pipe 1.
, and push in while rotating the entire outer tube 1 and pile tip 2. Excavation is carried out by the digging blade 4 of the pile tip 2, and the ground is loosened by pressurized air or water jetted from the nozzle hole 5, and the outer pipe 1 is press-fitted into the ground by the pushing force and rotation due to the vertical load. be done. In the process of press-fitting the outer pipe 1, the penetration speed, the rotating load current at the pile tip and the pile body, the rotational speed of the outer tube and its elapsed time, and the pressure air or pressure water jetting pressure at the tip of the pile tip 2 are detected. , this is recorded. When the outer tube 1 is press-fitted to a predetermined depth as shown in FIGS. 1B and 2, the hollow rod 6 is then reversed as shown in FIG. The rod 6 is pulled up and extracted, and the water level gauge 13 is inserted into the porous pipe 8, leaving the pile tip 2 and measuring pipe 3 in the ground, as shown in FIGS. 1D and 3. Since the measurement pipe 3 has a structure in which a perforated pipe 8 is inserted into the core of the composite body 7, groundwater flows into the inside of the perforated pipe 8, and fluctuations in water level can be measured by the water level gauge 13. The external force is transmitted, and the vibration meter 9,
Underground fluctuations can be measured by the strain gauge 10 and the earth pressure gauge 11, and water pressure fluctuations can be measured by the water pressure gauge 12. By the way, in order to understand the soil properties obtained by penetrating the outer pipe 1, we analyze the measured values by penetrating several outer pipes and make judgments based on this.Next, we determine the soil type. Examples of determination of N value and support capacity are shown below.

〔effect〕

As described above, since the present invention has the above configuration, it is possible to measure the penetration depth, rotational torque, load current value, and rotational speed during penetration, and to measure the earth pressure, water pressure, distortion, vibration, and water level after penetration. By combining both types of data, ground analysis can be performed more accurately and with high reliability. By performing measurements during and after penetration simultaneously and continuously using the same device, a lower cost construction method can be realized compared to the case where these two measurement means were originally used separately. Furthermore, various sensors to be set inside the composite measuring tube can be installed in advance, thereby reducing the amount of work required on site with poor working conditions. Immediately after penetration, simply by pulling out the outer tube, the various sensors are placed in a state where they can start measuring, which greatly improves work efficiency and has excellent practical effects.

[Brief explanation of the drawing]

Fig. 1 is a process diagram of the measurement method according to the present invention, Fig. 2 is an enlarged cross-sectional view when the outer pipe is penetrated, Fig. 3 is an enlarged cross-sectional view of the measurement pipe with the outer pipe pulled out, and Fig. 4 is the penetration device. An explanatory diagram, Figure 5 is a block diagram leading to the recorder, Figure 6 is an explanatory diagram showing an example of recording, and Figure 7 is an explanatory diagram showing an example of recording.
The figure is a longitudinal sectional view showing an example of a small diameter outer tube. 1...Outer pipe, 2...Pile tip, 3...Measuring tube, 5...
... Nozzle hole, 6 ... Hollow rod, 7 ... Composite body,
8...Porous pipe.

Claims (1)

[Claims] 1 A sensor for observing ground dynamics is installed in a measurement pipe housed inside the outer pipe, and pressurized fluid is supplied through a hollow body inserted into the measurement pipe while rotating the outer pipe and the pile tip installed at the opening at one end of the outer pipe. eject into the ground, penetrate the outer pipe into the ground with a vertical load, measure the depth, rotational torque, load current value, rotation speed, and ejection pressure of the pressure fluid at the time of penetration, and extract the outer pipe after penetration, A ground investigation and measurement method characterized in that the movement of the ground is measured by the sensor installed in the measurement pipe.