JPS62280410A - Ground improver - Google Patents

Abstract

PURPOSE:To form an improved column exactly set on the 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 frequency to regulate a given strength possessed by a target 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 values of current are greater than a set value are provided. Also, a counter to integrate frequency by signals coming from the comparator, a frequency setter to set up frequency corresponding to the strength of a target ground in the ground, and a frequency comparator to send out stop signal to a driver 6 when the integrated frequency is greater than a set frequency are provided. The position of bearing ground having a given strength can thus be detected' exactly and automatically, permitting the ground having good and constant quality to be available.

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) As a conventional soil improvement machine, the agitator is fixed at the tip, the agitator is positioned along the leader in the Itα direction, and the agitator shaft is rotated by a rotary drive motor. At the same time, the stirring shaft is lowered using a winch or other drive mechanism, and after stirring to a predetermined depth, stirring is carried out using stirring blades, and in step 6, an improving material such as cement is injected from the tip of the stirring shaft. There is a known method in which the stirring shaft is pulled up by the above-mentioned driving device while the stirring is being carried out to form an improved columnar body.

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 sprays the improving material must reach the supporting ground under the soft layer. It is necessary to form an improved column that penetrates into the ground and firmly rests 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. From the fact that the strength of the ground is proportional to the current value of the rotary drive motor of the stirring shaft, the operator can determine the current value during the penetration work of the stirring shaft while referring to the above depth. By monitoring changes in the flow rate with a Ti flowmeter, it is determined whether the supporting ground has been reached or not.
Previously, a method was used to determine whether the product had bottomed out on the supporting ground on an individual basis 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 polling results shown above by the dashed line in Figure 1 is plotted as the depth of the supporting ground surface. If it is used all at once and an improved column is formed from that position, in areas where the supporting ground surface is deeper, the improved column will be formed floating in the soft ground layer, making it impossible to achieve the purpose of ground improvement. On the other hand, in areas where the supporting ground surface is shallower, the tip of the stirring shaft may penetrate into the supporting ground, which may reduce construction efficiency, shorten the life of the stirring blade or rotary drive motor, or cause damage. Ta.

In addition, when workers judge the current value visually, it is difficult to read the current value accurately because the ammeter swings 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 - there was a risk that the supporting strength required of the ground after C1 ground improvement construction could not be expected. .

Furthermore, in the case of using the above-mentioned ammeter, the appropriateness 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, so the worker making the judgment is subject to excessive mental stress. There was a risk that the construction efficiency would be reduced.

(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 ground improvement machine having a stirring shaft that is rotatably driven by a rotary drive motor and is driven up and down by a drive device, in which a current for setting an allowable current value of the rotary drive motor during rotation drive is provided. A value setting device, a current value detector for detecting the current value of the rotational drive motor during rotational driving, and the above '11! A current value comparison circuit that compares the current value set value and the detected value and issues a signal when the detected value is larger; a counter that integrates the frequency based on the signal issued by this comparison circuit; A power setter for setting the power corresponding to the strength, and a stop signal is sent to the drive device when the cumulative power of the counter is compared with the set power of the power setter and the cumulative power is greater than the set power. This soil improvement machine is equipped with a frequency comparison circuit that emits a frequency.

In the above configuration, if the allowable current value determined by the rotary drive motor's mechanical capacity and the frequency for regulating the specified strength of the target supporting ground are set, the tip of the stirring shaft can be A load is applied to the rotary drive motor as the stirring blades installed in the rotary drive motor come in contact with the supporting ground while rotating, and the detected current value can track the set current value, and by comparing the number of times it exceeds the set value, it is determined that the current value remains constant. It is possible to detect the position of the supporting ground having a strength of 1,000,000,000,000,000,000,000,000,000.

(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, the elevating section! The basic structure is provided with a driving equipment 6 and the like for causing lI, and a hose 7 from an improved material plant (not shown) is connected to the upper end of the stirring shaft 4 via a swivel joint 8.

Then, as shown in FIG.
A supporting ground position detecting device A is provided which detects the position of the supporting ground based on the current value and controls the driving of one drive unit 100.

This supporting ground position detection device! A compares the current value setter 9 for setting the allowable current value of the rotary drive motor 5, the current value setter 10 of the rotary drive motor 5 during rotational drive, and the set current value and the detected m current value. a current value comparison circuit 11 that emits a pulse signal when the detected current value h is large;
A pulse counter 12 that integrates the number of pulses according to the pulse signal generated by the comparison circuit 11, a pulse number setter 13 that sets the target number of pulses, and the integrated number of pulses and the number of pulses in the pulse counter 12. A pulse number comparison circuit 14 is provided which compares the number of pulses set by the setting device and issues a stop signal to the drive f1 device 6 when the cumulative number of pulses is larger than the set number of pulses.

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. The pulse signal generated by the value comparison circuit 11 intermittently generates a pulse wave only when the detected current value exceeds the set current value.

Further, the number of pulses set in the pulse number setting device 13 is a value determined by the strength of the target supporting ground, and the stop signal to the drive device 6 issued by the pulse number comparison circuit 14 is manually controlled. I] It acts preferentially on the drive device 6 to stop its drive even when the device is being controlled.

When the stirring blade 3 is rotated to stir the soft ground using this ground improvement pit and the stirring shaft 4 is inserted, the rotational resistance acting on the stirring blade 3 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. The strength of a given ground can be detected by comparing it with

Then, as shown in FIG. 1, the stirring 1
The bar-shaped stirring m3 provided at the tip of the sleeve 4 comes into contact with the sleeve 4, the detected current value increases rapidly, and a pulse signal is emitted by the current value comparison circuit 11. After scraping off a part of the convex part, the adjacent one The agitation 113 rotates and comes into contact again, and a pulse signal is generated.

During this time, the stirring shaft 4 is also kept dry, and the above-mentioned contact and pulse signal transmission are repeated, so that the improved column P that is formed has a predetermined strength that can effectively transmit the overburden load to the supporting ground. Reach the location of the supporting ground with.

Therefore, by regulating the frequency of the pulse signal, that is, the number of pulses, it is possible to obtain the position of the supporting ground that has a constant supporting strength among the supporting ground that is the foundation on which the improved column P is placed on the bottom.

When the set number of pulses is reached, the drive device 6 that lowers the stirring shaft 4 is automatically stopped, and the tip of the stirring shaft is While spraying and stirring the improved material that has been pressure-fed to the discharge port of the improved column P, the stirring shaft 4 is pulled up and the improved column P is
We will move on to the work of forming the

Thereby, it is possible to form the improved column 1 which is firmly planted on the supporting ground and has a constant strength depending on the actual supporting ground.

In addition, the support ground position detection device of this embodiment includes a means for limiting the pulse number integration by the pulse counter 12 depending on the position of the moving shaft 3, that is, the depth.

This is because when a hard stratum S' exists in the surface layer near the upper surface of the soft ground S, the current value of the rotary drive motor 5 increases due to the hard stratum S', and the pulse counter 12 integrates the number of pulses. This was provided to prevent this from happening.

This pulse number 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 is activated to turn on when the detected depth exceeds a set depth, and a normally open contact 19 in this electromagnetic relay is interposed between the current value comparison circuit 11 and the pulse counter 12. ing.

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 pulse counter 12 starts integrating the number of pulses after the influence of the hard surface layer S' has disappeared, so the supporting ground can be adjusted according to the actual ground condition. 1 position can be detected.

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

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 frequency for regulating the target predetermined strength of the supporting ground can be set. By simply placing the device in place, a support positioning device with a certain level of strength can be detected reliably, quickly, and automatically.

This eliminates the mental burden on the worker when determining whether the stirring shaft will reach the bottom, speeds up the decision to reach the bottom, and eliminates unnecessary penetration into the supporting ground, improving construction efficiency and minimizing the consumption of improvement materials. In addition to this, it is possible to form improved pillars that are anchored to the supporting ground with a certain level of strength depending on the actual supporting ground, making it possible to improve the ground with good and consistent quality. Ru.

[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, H
... Supporting ground, P ... Improved column, 3 ... Stirring blade,
4... Stirring shaft, 5... Rotation drive motor, 6... Drive device, 9... Current value setter, 10...' upstream value detector, 11... Pulse number comparison circuit, 12 ... Pulse counter, 13... Pulse number setting switch, 14... Pulse number 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 emits a signal when the detected value is larger, a counter that integrates the frequency based on the signal emitted by this comparison circuit, and a frequency that corresponds to the target ground strength in the ground. a power setting device for setting the power, and a power comparison circuit that compares the cumulative power of the counter with the set power of the power setter and issues a stop signal to the drive device when the cumulative power is greater than the set power. A ground improvement machine characterized by the following.