JPS62280411A - Ground improver - Google Patents

Abstract

PURPOSE:To form an improved column exactly set on bearing ground by detecting the position of bearing ground having a fixed strength by a method in which an allowable current value for a revolving motor and a time value to regulate a given strength possessed by a target bearing ground are set up. CONSTITUTION:A current value setter to set up an allowable current value for a revolving motor 5 in operation and a current value comparator to send out signals when detected current value is greater than a set value are provided. Also, a counter to integrate signal-generating time by signals from the comparator, a time value setter to set up time values corresponding to the strength of a target ground in the ground, and a time value comparator to send out stop signal to a driver 6 when the integrated time value is greater than a set time value are provided. The position of bearing ground having a given strength can thus be detected exactly and automatically to enable one to improve it to ground having good and constant quality.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention provides a method for ensuring that the improved column remains constant when forming the improved column on the supporting ground in soft ground. The present invention relates to a soil improvement machine that can be automatically controlled so that the ground is formed by landing on the supporting ground.

(Prior art) Conventional soil improvement machines have a stirring shaft with a stirring blade fixed to the tip that is adjusted in the vertical direction along a leader, and a rotary drive motor drives the stirring shaft and drives a winch, etc. The stirring shaft is lowered using the II device,
After stirring and penetrating to a predetermined depth, l! It is known to form an improved column by pulling up the stirring shaft using the driving device while injecting an improving material such as cement from the tip of the stirring shaft.

In soil improvement using this soil improvement machine, in order to effectively transmit the superimposed load acting on the improved column to the supporting ground, the tip of the stirring shaft that spouts the improvement material must reach the supporting ground under the soft layer. It is necessary to form an improved column that is firmly planted on the supporting ground.

For this reason, the depth to the supporting ground is confirmed in advance by preliminary polling before ground improvement, and this depth is used as the penetration depth of the stirring shaft, and it is uniformly applied to multiple improved pillars to improve the supporting ground. Since the strength of the ground is proportional to the current value of the rotary drive motor of the stirring shaft, the worker can calculate the current value during the penetration work of the stirring shaft while referring to the above depth. The conventional method was to monitor changes with an ammeter to determine whether or not the support ground had been reached, and to determine whether the object had bottomed out on the support ground individually depending on the actual ground.

However, the depth of the supporting ground under the soft ground layer is not necessarily constant even at the same construction site, so for example, the position determined from the above polling result shown by the single point Wi line in Figure 1 is taken as the depth of the supporting ground surface. If improved pillars are formed from that position by uniform use, in areas where the supporting ground surface is deeper, the improved pillars will be formed floating in the soft ground layer, making it difficult to achieve the purpose of ground improvement. I can't do it,
On the other hand, in areas where the supporting ground surface is shallower, the tip of the stirring shaft penetrates into the supporting ground, which may reduce construction efficiency, shorten the lifespan of the stirring blades or rotary drive motor, or cause damage.

In addition, when workers judge the current value visually, it is difficult to accurately read the current value because the ammeter takes pictures due to inertia, and it is difficult to accurately read the current value at which point the tip of the stirring shaft touches the supporting ground. There were individual differences in the judgment of whether or not the ground had reached the bottom, and there were variations in the ground strength of the supporting ground that was judged to have reached the bottom, and there was a risk that the supporting strength required of the ground after ground improvement work could not be expected. .

Furthermore, when using the above-mentioned ammeter, the suitability of determining whether or not the bottom has hit the ground is directly connected to the quality of the ground improvement and may cause damage to machinery and equipment, placing an excessive mental burden on the worker making the determination. There was a risk of reducing construction efficiency.

(Objective of the Invention) In view of the above-mentioned circumstances, the present invention is capable of reliably and automatically detecting the supporting ground position having a predetermined strength, thereby making it possible to improve the ground with good and consistent quality.
The purpose of this invention is to provide a ground improvement machine that can improve construction efficiency.

(Structure of the Invention) The present invention provides a method for setting an allowable current value of the rotary drive motor during rotation in a ground improvement machine having a stirring shaft that is rotationally driven by a rotary drive motor and is driven up and down by a drive device. A current value setter and a current value detector for detecting the current value of the rotary drive motor during rotation drive compare the set value of the current value and the detected value and generate a signal when the detected value is larger. A current value comparison circuit that emits a current value, a counter that integrates the signal generation time based on the signal from this comparison circuit, a time value setting device for setting a time value corresponding to a target ground strength in the ground, and the above-mentioned counter. The soil improvement machine is equipped with a time value comparison circuit that compares the accumulated time value at the time value set with the set time value at the time value setter and issues a stop signal to the drive device when the accumulated time value is greater than the set time value. It is composed of

In the above configuration, if the allowable current value determined from the mechanical capacity of the rotary drive motor and the time value for regulating the predetermined strength of the target supporting ground are set,
As the stirring blades installed at the tip of the stirring shaft rotate and come into contact with the supporting ground, a load is applied to the rotary drive motor.
When the detected current value exceeds the set current value, by comparing the cumulative time value of the time exceeding the set time value with the set time value, it is possible to detect the supporting ground position with a certain strength. It is easy to form improved columns that are firmly planted on the ground.

(Example) Fig. 1 shows a state in which an improved column is formed using a soil improving machine according to an embodiment of the present invention, and Fig. 2 shows a block diagram of the main parts of the present invention.

The soil improvement machine shown in FIG. 1 includes a base machine 1 equipped with a leader 2 and a stirring shaft 4 having stirring blades 3 at its tip, and a rotary drive motor 5 for rotationally driving the stirring shaft 4.
．． Similarly, a drive device 6 etc. to move the elevating section vJ is provided, and stirring @
At the upper end of 4 is a hose 7 from an amendment plant (not shown).
are connected via a swivel joint 8 to form the basic configuration.

Then, as shown in FIG.
A support ground position detection device A is provided which detects the position of the support ground based on the current value and controls the drive stop of the drive device 6.

This support ground position detection device includes a current value setter 9 for setting the permissible current value of the rotation drive motor 5, and a current value detection unit 9 for the rotation drive motor 5 during rotation drive.
0 and settings? tf flow value and detection'! A current value comparison circuit 11 that compares current values and issues a pulse signal when the detected current value is larger; a time counter 12 that starts integrating time based on the signal from this comparison circuit 11; The time value setter 13 for setting compares the cumulative time value of the time counter 12 with the set time value of the time value setter 13, and when the cumulative time value is greater than the set time value, the driving is performed. Bag V! 16 and a dark value comparison circuit 14 for issuing a stop signal.

Here, the allowable current value set in the current value setting device 9 is a value determined by the mechanical capacity of the rotary drive motor 5, and is, for example, a current value corresponding to 100% torque of the rotary drive motor 5, and a current value that corresponds to 100% torque of the rotary drive motor 5. The signal generated by the value comparison circuit 11 is for keeping the time counter 12 in the ON state only while the detected current value exceeds the set current value.

The time value set in the time value setter 13 is a value determined by the strength of the target supporting ground, and the stop signal to the drive 1dt6 issued by the time value comparison circuit 14 is determined by the drive unit 1dt6 with assistance. Even when υ control is being performed, it preferentially acts on the drive device 6 to stop its drive.

Using this ground improvement machine, when the stirring shaft 4 is penetrated while stirring the soft ground by rotating the stirring shaft 3, the rotational resistance acting on the stirring 'lA3 changes depending on the strength of the ground. As a result, the load acting on the rotary drive motor 5 changes.

This change in the strength of the ground is interpreted as a change in the current value flowing through the rotary drive motor 5, and by detecting this current value, it is possible to obtain a relative change in the strength of the ground, and it is possible to compare the current value with the preset current value. By comparing, the strength of a given ground can be detected.

And, as shown in Figure 1, there is a hard supporting ground below the soft ground layer S! In the convex part of the unevenness that exists on the upper surface of +-1,
The rod-shaped stirring blade 3 provided at the tip of the stirring shaft 4 comes into contact with the stirring shaft 4, the detected current value increases rapidly, a signal is generated by the current value comparison circuit 11, and the stirring blade 3 scrapes off a part of the protrusion. After that, another adjacent stirring blade 3 rotates and comes into contact with the protrusion again, and a signal is emitted.

During this time, the stirring shaft 4 is also lowered, and the above-mentioned contact and signal transmission are repeated intermittently, and finally the signal is continuously emitted, and the improved column P that is formed effectively handles the applied load. The position of the supporting ground is reached which has a predetermined strength such that it can be transmitted to the supporting ground.

Therefore, by regulating the cumulative value of the time during which the above-mentioned signal is emitted, that is, the cumulative time value, the position of the supporting ground that has a certain support strength among the supporting ground that is the foundation on which the improved column P is bottomed can be determined. Obtainable.

Then, when the cumulative time value reaches the set time value, the drive unit that was lowering the stirring shaft 4 stops the automatic fishing, and connects the hose 7, swivel joint 8, and inside of the stirring shaft 4 from the improved material plant. While spraying and agitating the improving material that has been force-fed to the discharge port at the tip of the itching shaft, the work moves on to forming the improved column P by pulling up the stirring shaft 4.

Thereby, it is possible to form the improved column P which is reliably planted on the supporting ground having a constant strength depending on the actual supporting ground.

In addition, in the support ground position detection 5A of this embodiment, the Ki calculation of the time at the time counter 12 is calculated based on the position of the stirring blade 3,
In other words, a means for limiting based on depth is added.

This is because the hard ground layer S' is located near the surface of the soft ground S.
This is provided to prevent the current value of the rotary drive motor 5 from increasing due to the hard stratum S' and being integrated by the time counter 12 as a time exceeding the allowable current value, when .

This time integration limiting means includes a depth detector 15 that detects the depth of the stirring shaft 4, a depth setter 16 that sets the depth to be limited, and a depth comparison circuit 17 that compares the detected depth and the set depth. , an electromagnetic relay 18 that operates and turns on when the detected depth exceeds the set depth,
A normally open contact 19 in this electromagnetic relay is interposed between the mainstream value comparison circuit 11 and the time counter 12.

The depth detector 15 can be applied in various ways in relation to the vertical movement of the stirring shaft 4 or to a driving device, and as shown in FIG. A depth detector is used that detects the vertical movement of the wire lobe by converting it into a rotation angle, and converts it into depth using an encoder using a pulse signal or synchro signal.

The depth set by the depth setter 16 may be set, for example, to a depth at which the influence of the hard surface layer S' from the ground surface disappears.

By adding such a limiting means, the time counter 12
Since time integration is started at , the position of the supporting ground H can be detected according to the actual ground condition.

The display means indicated by 20 in Fig. 2 is a warning lamp, a warning buzzer, etc. that informs the work sound that the stirring shaft has reached the target supporting ground, and the construction record output indicated by 21 is as follows.
For example, the set current value, set time value, and the depth at which the target supporting ground is reached are recorded for each improved social structure.

In addition, in the present invention, changes in the strength of the ground are detected by the rotary drive motor 5.
However, by using the power consumption value of the rotary drive motor 5 instead of this current value and detecting the change, it is also possible to detect a change in the strength of the ground.

(Effects of the Invention) According to the ground improvement machine of the present invention, the allowable current value determined from the mechanical capacity of the rotary drive motor and the time value for regulating the target predetermined strength of the supporting ground can be set. By simply setting the support ground position with a certain level of strength, the position of the supporting ground can be reliably, quickly, and automatically detected.

This eliminates the psychological negative effects of working noise when determining when the stirring shaft hits the bottom, and it also speeds up the determination of when the stirring shaft hits the bottom and eliminates unnecessary penetration into the supporting ground, improving construction efficiency and reducing the consumption of improved materials. In addition to being able to reduce the amount of ground that is being supported, it is also possible to form improved pillars that rest on the supporting ground with a certain level of strength, depending on the actual supporting ground, so that good and consistent quality ground improvement can be achieved. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a simplified explanatory diagram showing a construction state according to an embodiment of the present invention, and FIG. 2 is a block diagram of the main parts of the present invention in the embodiment of FIG. A... Support ground position detection device, S... Soft ground, Todo... Support ground, P... Improved column, 3... Stirring blade,
4... Stirring shaft, 5... Rotation drive motor, 6... Drive @ device, 9... Current value setter, 10... Current value detector, 11... Current value comparison circuit, 12... Time counter, 13... Time value setter, 14... Time value comparison circuit.

Claims (1)

[Claims] 1. In a ground improvement machine having a stirring shaft that is rotationally driven by a rotary drive motor and is driven up and down by a drive device,
A current value setter for setting an allowable current value of the rotary drive motor during rotational drive, a current value detector for detecting the current value of the rotary drive motor during rotational drive, and a set value of the above current value. A current value comparison circuit that compares the detected value and issues a signal if the detected value is larger, a counter that adds up the signal generation time using the signal from this comparison circuit, and corresponds to the target ground strength in the ground. A time value setter for setting the time value to be set, compares the cumulative time value of the counter with the set time value of the time value setter, and when the cumulative time value is greater than the set time value, the driving device A ground improvement machine characterized by comprising a time value comparison circuit that issues a stop signal.