JP6153591B2 - Ground survey method and ground survey device - Google Patents

Description

  In the present invention, when excavating the ground with a rod having excavating blades to form a columnar improved pile, data having a correlation with a graph of N value obtained in advance by a boring survey can be extracted. It relates to the survey method.

  In general, when constructing a structure, a ground survey is conducted in advance to investigate the depth and hardness of the supporting ground. However, when such a survey is conducted, a borehole standard penetration test (hereinafter referred to as a borehole survey) is conducted. Etc.) to check the depth and hardness to the support ground. In this boring survey, a 63.5 kg weight was attached to a pulley attached to the top of a framed ridge through a rope. The number of times is recorded as an N value, and a graph of “N value−depth” can be generated as shown in FIG.

  By the way, after investigating the ground in this way, the ground is reinforced by forming columnar improved piles etc. based on the survey results, but the results obtained in the boring survey may be falsified. In some cases, columnar piles cannot be formed up to the supporting ground.

  On the other hand, when forming the pillar-like improved pile, the current value of the motor that drives the stirring shaft, the number of rotations of the stirring shaft, the penetration speed of the stirring shaft, etc. are extracted, thereby the depth to the support ground Various devices have been proposed (such as Patent Document 1 and Patent Document 2).

  Such an apparatus is capable of generating excavation energy every 1 meter and 0.1 meter near the support ground from the current value of the rotational drive motor that drives the stirring shaft, the rotational speed of the stirring shaft, and the penetration speed of the stirring shaft. The change of the excavation energy every 0.1 meter is sequentially displayed on the monitor, and when the excavation reference energy of the support ground obtained by the drilling survey in advance is reached, the tip of the agitation shaft becomes the support ground position. It is determined to have reached.

JP-A-11-280055 JP 2008-101388 A

  However, since each of the data obtained by such current value, rotation speed, penetration speed, etc. has no correlation with the graph of N value of the borehole survey conducted in advance, the current value is correct. It is impossible to determine whether the N-value data is correct. Further, in Patent Document 1, the energy during excavation is calculated and displayed on the monitor using the current value of the motor, the rotation speed of the stirring shaft, the penetration speed of the stirring shaft, and the like. This method has a problem in that the measurement of the current value of the motor, the sensor for detecting the rotational speed, the sensor for detecting the penetration speed, and the like are required, and the cost is high.

  Accordingly, the present invention aims to provide a ground survey method that enables excavation while extracting data correlated with a graph of N value at the time of boring survey, focusing on the above problems. To do.

That is, in order to solve the above problems, the present invention provides a ground survey method in which excavation can be performed while extracting data having a correlation with a graph of N value at the time of boring survey, and a rod is rotated by a hydraulic motor. However, when penetrating the rod into the ground, the step of measuring the hydraulic pressure value of the hydraulic motor at regular intervals and the sum of the hydraulic values measured at regular intervals are extracted each time a predetermined excavation distance is reached. Output step.

According to the present invention, ball-ring can have a correlation with the graph of N values during investigation, consisting generated graph shape to be able to determine the correctness of the data at the time of boring survey.

The figure which shows the excavation stirring apparatus which shows one embodiment of this invention Functional block diagram in the same form The figure which shows the display part and hydraulic pressure sensor in the same form Graph of N value in the same form Drilling process diagram in the same form The figure which shows the rod and penetration member in other embodiment

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

  The ground investigation method in this embodiment has a correlation with the N value graph obtained in advance by the boring investigation when the columnar improved pile is formed on the ground using the excavating and stirring device 1 as shown in FIG. When the rod 2 of the excavating and stirring device 1 is rotated to excavate the ground, the hydraulic value of the hydraulic motor 3 for rotating the rod 2 is set at regular intervals. The graph is generated by measuring and extracting the sum of the hydraulic pressure values measured at regular intervals within a predetermined time. Hereinafter, the ground investigation method in the present embodiment will be described in detail.

  First, the excavation and stirring device 1 in which this ground investigation method is used is used by being attached to an improved machine body such as a crawler type three-point support machine, a rough terrain type support machine, a simple three-point support machine, As shown in FIG. 1, a rod 2 having a hollow portion for discharging solidified material slurry along the axial direction, a hydraulic motor 3 for rotating the rod 2, and a lower surface of the rod 2 attached to the ground , The agitating blade 22 attached to the upper part of the excavating blade 21 and rotating together with the rod 2, and between the excavating blade 21 and the agitating blade 22 and rotating with respect to the rod 2. It is configured with a co-rotation prevention wing 23 and the like that can be freely attached.

  Among these, the rod 2 provided with this hollow portion can be set to a certain length by connecting a plurality of hollow rod elements 20 having a hollow inside, and is a length necessary for ground improvement. Set to Then, the upper end side of the connected rod 2 is connected to the hydraulic motor 3 of the improved machine body, and the solidified material slurry fed from the plant 7 is rotated in one direction with respect to the traveling direction during excavation. It is injected from the vicinity of the upper end portion, and the solidified material slurry is discharged from the discharge port 24 on the lower end side.

  The excavation blade 21 attached to the tip end side of the rod 2 is constituted by a plurality of wing bodies and excavates the ground. A comb-like excavation blade is attached to the lower side of the wing body in an oblique direction. Composed. Then, the ground is excavated by the excavating blade so that the earth and sand can be discharged upward.

  Further, the stirring blade 22 provided above the excavating blade 21 is constituted by a rectangular plate-shaped blade body having substantially the same diameter as the excavating blade 21, and these two blade bodies are attached to the rod 2. It is attached and provided so as to be axially symmetric. This wing body is attached so as to incline the plate-like body as a whole, and is attached in such a direction that the earth and sand in the excavation hole is discharged upward during excavation. And while discharging the earth and sand upward by the stirring blade 22 provided up and down, the earth and sand and solidification material slurry are made to stir by the inclined blade body.

  The rod 2 including the excavating blade 21 and the stirring blade 22 is driven to rotate by the hydraulic motor 3. The hydraulic motor 3 is configured such that the rod 2 is rotationally driven by the hydraulic pressure supplied from the hydraulic tank 31, and the hydraulic pressure is measured by the hydraulic sensor 32. When measuring the oil pressure, the oil pressure is measured at regular intervals, and the measured value is stored in the storage unit 4 (see FIG. 2). When measuring the hydraulic pressure, as shown in FIG. 3, a hydraulic sensor 32 is attached to a position branched from the piping from the hydraulic tank 31 to the hydraulic motor 3, and an output value from the hydraulic sensor 32 is output to the storage unit 4. And stored at regular time intervals (for example, every minute).

In addition, the rod 2 of the excavation stirring device 1 is provided with a depth meter 25 for measuring the excavation depth. The depth meter 25 can be a linear displacement meter provided to contact the rod 2 or a potentiometer using a string, and the excavation depth of the rod 2 is sequentially output to the storage unit 4 for storage. Like that. The timing for measuring the excavation depth is 1 meter, and the timing is output to the calculation unit 5 .

In general, when drilling the ground with a rod 2, hydraulic pressure value varies depending on the kind of the soil layer. Specifically, when excavating the sand layer, the hydraulic pressure value slightly moves, and when excavating the clay layer, it gently meanders according to the hardness of the ground. On the other hand, when excavating the gravel layer, the waveform greatly fluctuates according to the size of the gravel. When excavating such a layer, even if it is a sand layer or clay layer, there may be large gravel, etc., and the hydraulic pressure may fluctuate greatly. In many cases, it cannot be determined whether it corresponds to For this reason, in this embodiment, even if there is a large fluctuation or the like by adding this hydraulic pressure value in a certain time unit by the arithmetic unit 5, this is smoothed and correlated with the N value graph. I try to have it. Here, the “constant time unit” means, for example, that the hydraulic pressure value is added in units of time when excavating 1 meter. In this way, “to penetrate 30 centimeters” when generating N-value data corresponds to “excavating 1 meter” of the rod 2, and “the number of impacts of the weight” and “sum of hydraulic values” "Can be made to correspond to each other, and a correlation can be given .

Next , the process in the case of forming a columnar improvement pile while performing ground investigation using the excavation stirring apparatus 1 configured as described above will be described using the flowchart of FIG .

  First, when excavating the ground, the rod 2 is erected with the excavating blade 21 and the stirring blade 22 attached to the tip of the rod 2, and the hydraulic motor 3 is driven to press the ground while rotating the rod 2. (Step S1). Then, the hydraulic pressure value is measured by the hydraulic pressure sensor 32 and stored in the storage unit 4 (step S2).

  In parallel with this, the depth of excavation of the rod 2 is measured by the depth meter 25 (step S3), and the signal is output to the calculation unit 5 every time one meter is excavated (step S4).

The computing unit 5 reads out the hydraulic pressures stored in the storage unit 4 at the timing when the depth meter 25 excavates 1 meter, adds them (step S5), generates a graph, and displays it on the display unit 6 (Step S6). Thus generated graph, because it has a correlation with the graph of N values during boring investigation, it is possible to confirm the authenticity of the N values during boring survey.

  After excavating to the supporting ground in this way (step S7), this time the solidifying agent slurry is supplied from the plant 7 and discharged from the tip portion of the hollow rod 2, when the solidifying agent slurry is discharged. 2 is rotated in the reverse direction, and the rod 2 is pulled up while stirring the solidifying agent slurry or earth and sand with the stirring blade 22 (step S8).

  Thus, according to the above embodiment, when excavating the ground with the rod 2 having the excavating blades 21, the hydraulic pressure value of the hydraulic motor 3 is measured every minute, and the rod 2 is excavated for 1 meter. Since the sum of the hydraulic values within the time is extracted, it can be correlated with the graph of the N value at the time of the boring survey, and the correctness of the data at the time of the boring survey is judged from the generated graph shape. Will be able to.

  In addition, since the predetermined time is the time until the rod 2 is excavated by 1 meter during excavation, it can be associated with the N value data when penetrating a predetermined distance during a boring survey, and can have a correlation. become able to.

  In addition, this invention is not limited to the said embodiment, It can implement in a various aspect.

For example, in the above embodiment, the structure in which the excavating blade 21 and the like are attached to the tip of the rod 2 has been described as an example. However, the excavating blade 21 is provided in a direction perpendicular to the axial direction of the rod 2. Therefore, it has a large resistance when the rod 2 penetrates. For this reason, there is a possibility that it cannot be accurately correlated with the N value data obtained at the time of penetration of the rod in the boring survey. Therefore, as shown in FIG. 6 , a penetrating member 26 having a shape like a screw point used for a Swedish sounding test at the tip of the rod 2, or a penetrating member having a substantially conical shape with a sharp tip, etc. It is also possible to extract the sum of hydraulic pressure values by a similar method. In this case, the penetrating member 26 is preferably a member having a width of about 1.0 to 1.5 times the diameter of the rod 2.

  In the above embodiment, the hydraulic pressure value is measured every minute, but the time can be appropriately changed according to the on-site environment.

  In the above embodiment, when extracting the sum of hydraulic pressure values, the sum is extracted in the time required for 1 meter excavation. However, the excavation depth can be appropriately changed according to the master disk environment and the like. .

DESCRIPTION OF SYMBOLS 1 ... Excavation stirring apparatus 2 ... Rod 20 ... Hollow rod element 21 ... Excavation blade 22 ... Agitation blade 23 ... Co-rotation prevention blade 24 ... Discharge port 25 ... Depth Total 3 ... Hydraulic motor 31 ... Hydraulic tank 32 ... Hydraulic sensor 4 ... Storage unit 5 ... Calculating unit 6 ... Display unit 7 ... Plant

Claims (2)

In the ground survey method that allows excavation while extracting data correlated with the N value graph at the time of drilling survey,
Measuring the hydraulic pressure value of the hydraulic motor at regular intervals when the rod penetrates the ground while rotating the rod with the hydraulic motor;
A step of extracting and outputting the sum of hydraulic pressure values measured every predetermined time each time a predetermined excavation distance is reached;
A ground survey method characterized by comprising : In the ground survey device that enables excavation while extracting data correlated with the graph of N value at the time of boring survey,
Measuring means for measuring the hydraulic pressure value of the hydraulic motor at regular intervals when the rod penetrates the ground while rotating the rod with the hydraulic motor;
Extracting means for extracting and outputting the sum of the hydraulic pressure values measured every predetermined time each time a predetermined excavation distance is reached;
A ground surveying device characterized by comprising:

Images