JP3430148B2 - Ground improvement construction method and construction management device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground improvement construction method for forming columnar piles by mixing improvement materials such as mortar and cement milk with in-situ soil in soft ground, and improving ground strength. Regarding the construction management device

[0002]

2. Description of the Related Art As a ground improvement construction, a chemical improver such as cement milk is discharged into the ground and agitated and mixed with in-situ soil to utilize the chemical bonding action with the improver.
There are methods of forming strong columnar piles, stabilizing soil properties and improving ground strength. The used construction device has a rotating shaft that is rotated by a drive motor and is moved up and down along a support leader, and a stirring blade that is rotated integrally with the rotating shaft. During the process of penetrating or pulling out to a predetermined depth, the stirring blade mixes the improvement material discharged into the ground with the in-situ soil. The improving material is supplied through a supply pipe arranged along the rotation axis, and is discharged from a discharge port provided at a root portion of the stirring blade into a cavity formed by rotation of the stirring blade, It is sprinkled on the rotation trajectory associated with the rotation and compulsorily mixed with the in-situ soil.

[0003]

In the above construction method, the degree of mixing of the in-situ soil and the improving material greatly affects the improving quality. For this reason, in the construction design, the target ground strength and properties are grasped by preliminary tests, and the discharge amount of the improvement material as well as the penetration and withdrawal speed, the number of stirring blades, the number of rotations per meter depth of the stirring blade, that is, the blades. It is important to set the number of cuts. That is, the penetration speed, the withdrawal speed, and the like are determined so that the target number of blade cuttings can be satisfied, but in that case, if the safety factor is increased, the construction efficiency is deteriorated. In actual construction, the construction location is often harder or softer than the ground strength of the preliminary test, and the rotation speed of the rotary shaft, the penetration speed, the extraction speed, etc. may deviate from the designed values. Therefore, from the viewpoint of construction evaluation, it cannot be expected that the number of blade cuttings will always meet the target number of blade cuttings in each part in the depth direction. I want to improve.

Further, the drive motor of the above construction apparatus is either an electric type or a hydraulic type, and is installed on the upper part of the support leader to rotate the rotary shaft through a connecting mechanism such as a gear and to rotate the rotary shaft. Is controlled from the base machine side on the ground. A hydraulic motor is generally smaller and lighter than an electric motor, and has an advantage that hydraulic equipment used on the base machine side, that is, hydraulic pressure or hydraulic oil for driving a motor can be used. However, in the hydraulic motor, the number of revolutions can be easily changed by changing the oil flow rate, but there is a mechanical problem that the number of revolutions easily varies depending on the hardness of the ground. For this reason, conventionally, when the target ground is relatively hard, an electric motor is used, and not only the cost required for the generator facility and the incidental facility cost are increased, but also the speed and efficiency of the construction are lacking.

An object of the present invention is to solve the above problems. Specifically, the target number of blade cuttings can be satisfied in each part in the depth direction, so that cost reduction and construction efficiency are improved, and at the same time, construction evaluation is further enhanced. Other purposes will be made clear in the following description.

[0006]

In order to achieve the above object, the ground improvement construction method of the present invention comprises a rotary shaft which is vertically moved along a support leader and is rotated by a hydraulic drive motor, Having a stirring blade that is rotated integrally with a rotating shaft, in the process of penetrating or withdrawing to a predetermined depth in the ground while rotating the rotating shaft, by the stirring blade, an improving material that is discharged into the ground, In the ground improvement construction method of mixing with in-situ soil, at the time of the penetration, the blade cutting number of the stirring blade is calculated for each predetermined depth of the rotating shaft, and the difference between the calculated value and the target blade cutting number is calculated. Calculated as the number of insufficient blade cuts for each of the predetermined depths, and at the time of withdrawal, the extraction speed of the rotary shaft is controlled according to each of the predetermined depths based on the number of insufficient blade cuts so as to reach the target number of blade cuts. It is characterized by that. Further, the present invention, when specified from the construction management device, is used for the ground improvement construction method, and from the rotation speed and the ascending / descending speed of the rotary shaft, the number of blade cutting of the stirring blade for each predetermined depth of the rotary shaft. Is calculated and the difference between the calculated value and the target number of times of blade cutting is calculated as the number of times of insufficient blade cutting for each predetermined depth, and the pulling speed of the rotating shaft is determined according to a predetermined depth so as to compensate for the number of times of insufficient blade cutting. It has a calculating means for calculating and a display means for displaying the drawing speed of the rotary shaft obtained by the calculating means in correspondence with a predetermined depth.

According to the above-mentioned features of the invention, the number of blade cuttings is calculated for each predetermined depth at the time of penetration, and is calculated as the number of insufficient blade cuttings (= target blade cutting number-calculated blade cutting number). At the time of pulling out, adjustment control is performed at a predetermined depth at each pulling speed of the rotary shaft (pulling speed for each predetermined depth) so as to reach the target number of blade cutting based on the number of insufficient blade cutting. As a result, the number of blade cuttings performed in the actual work surely satisfies the target number of blade cuttings for each predetermined depth as the sum of the penetration and the withdrawal. For this reason, in this configuration, the target number of blade cuttings is always satisfied for each predetermined depth, that is, each portion is always satisfied, so that construction quality and reliability of evaluation can be improved. At the same time, it prevents the blade cutting frequency from becoming partially insufficient or excessive, and enables quick and efficient construction. At the same time, the application of the hydraulic motor described in the above problem can be expanded to shorten the construction period and reduce the construction cost.

In the present invention described above, the meaning of each predetermined depth is
This means that when the rotary shaft (same as the stirring shaft) is penetrated or withdrawn, it is divided into unit depths such as 1 m or 50 cm. This unit depth is usually 50 cm to 1.
It is preferable to set it within the range of 5 m in terms of accuracy and speed control during drawing. The target number of times of blade cutting is the number of times of blade cutting for each construction area that is set as an optimum one during construction design.

The number of blade cuts at the time of penetration is, for example, the following formula (1)
Calculated from

[Formula 1]

In the method of the present invention, the blade cutting frequency T is calculated for each predetermined depth in the penetration process, and is calculated as the blade cutting frequency (T1, T2 ... Tx) corresponding to the depth. Also,
The difference between the number of blade cuttings (T1, T2 ... Tx) and the target number of blade cuttings (T0) is insufficient The number of blade cuttings (Tn1, Tn2 ... Tn)
x) is calculated for each predetermined depth. Then, the extraction speed of the rotary shaft is determined by the number of times of insufficient blade cutting (Tn1, Tn) for each predetermined depth.
It is calculated based on n2 ... Tnx). Each drawing speed is also derived based on the above equation (1).

The present invention described above is more preferably configured as described in claims 2 and 3. That is, first, the rotary shaft is forcibly moved up and down via a rack and pinion mechanism or the like attached along the support leader. This configuration
When the rotary shaft is forcibly moved up and down via a rack and pinion mechanism or the like, for example, the above-mentioned penetration speed v becomes mechanically constant, so that the operation of the construction management device of the present invention is simple and reliable. . Further, there is an advantage that more accurate control is possible even when controlling the drawing speed. Here, "the rotating shaft is forcibly moved up and down" refers to, for example, that the rotating shaft is always moved up and down at a design speed without being affected by the hardness of the ground side, and the known rack and pinion mechanism. It means moving up and down in conjunction with the mechanical movement of the chain mechanism and the like. Secondly, the improving material is discharged at least during the penetration process of the rotating shaft. As the discharge timing of the improved material, there are a mode of discharging only in the penetration process and a mode of discharging both in the penetration process and the withdrawal process. This is because, in the case of a structure that is satisfied every time, it is possible to make the overall mixing quality more uniform by exclusively discharging in the penetration process. However, it does not matter if the discharge timing is such that only the required depth range is discharged during the penetration process, or that discharge is performed to the necessary portion during the drawing process.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this explanation, first,
After describing an example of a construction device and a construction management device used when implementing the present invention, a construction method will be referred to. Note that FIG. 1 shows a schematic configuration of the entire construction apparatus and management apparatus, FIG. 2 schematically shows a control example of the method of the present invention, and FIG. 3 schematically shows a display example of an operator instruction unit.

(Example of Construction Device) In FIG. 1, a construction device for ground improvement is a traveling base machine 1, a support leader 2 erected on the base machine 1 via a hydraulic backstay 3 and the like, and a support leader 2. It includes a drive device 4 that is vertically moved on one side, a rotary shaft 5 that is rotated via the drive device 4, and the like. Here, the drive unit 4 is configured such that the movable body 7 is forcibly moved up and down by the mechanical engagement with the rack members 6 arranged above and below the support leader 2, and the hydraulic motor and the gear are moved relative to the movable body 7. The rotating shaft 5 is rotated by installing a connecting mechanism such as. The raising / lowering, that is, the vertical movement of the drive unit 4 is variably controlled by the operation unit 23 described later. The hydraulic motor doubles as a hydraulic power source of the hydraulic control device 10 installed on the base machine 1 side, and is driven by hydraulic oil supplied and discharged via a hydraulic pump and a pipe line (not shown). The rotating shaft 5 is provided with a supply pipe (not shown) inside, and the stirring blade 8 is provided on the lower side in a one-stage-total three blade configuration (this blade configuration is set appropriately in both the number of stages and the number of sheets). ing. Then, the improving material is transferred from the manufacturing plant 9 through the supply pipe, and is discharged from a discharge port provided at a root portion of the stirring blade 8 or the like into a void portion formed by rotation of the stirring blade 8. These structures are the same as before.

(Example of management device) The construction device described above includes a tachometer (rotation sensor) 11 attached to the drive device 4 side, and a mechanism portion 12 also installed on the lower side of the support leader 6 and serving as a rotation axis guide. A depth meter (depth sensor) 13 and a timer 14 and a speedometer 15 attached to the mechanism section 12, an arithmetic processing section 16 as arithmetic means, a display section 17 as display means, and an operator instruction section 18. have.

Of these, the tachometer 11 detects the number of rotations of the rotary shaft 5 and sends the detected data to the arithmetic processing section 16. The depth meter 13 detects the current depth of the tip of the rotary shaft 5, and the speedometer 15 detects the detection data of the depth meter 13 and the penetration or withdrawal speed of the rotary shaft 5 from the timer 14, and calculates the detected data. It is transmitted to the processing unit 16. Timer 14
The speedometer 15 may be built in the arithmetic processing unit 16. Although the arithmetic processing unit 16, the display unit 17, the instruction unit 18, and the like are schematically illustrated, they are actually installed in the operator room of the base machine 1.

The arithmetic processing unit 16 is an arithmetic unit (CPU).
Is input from the input unit 19 with a predetermined design target number of blade cutting, and the tachometer 11 and the speedometer 15
The following arithmetic processing is performed based on the detection data transmitted from the. That is, in the process of penetration of the rotating shaft 5, the number of blade cutting of all the stirring blades 8 is calculated for each unit depth according to the above formula (1), and as shown in FIG. 2, for each unit depth (0-1 m, 1-
2m, ... 4-5m) Number of blade cuttings (times / m)
To get At the same time, the number of insufficient blade cuts is calculated from the number of blade cuts for each unit depth. The number of insufficient blade cuts is the difference between the target number of blade cuts and the calculated number of blade cuts of the unit depth, and corresponds to Tn1 illustrated in the lower side of FIG. At the same time, the drawing speed of the rotary shaft 5 used in the drawing process is calculated for each unit depth using the above equation (1). The drawing speed for each unit depth is sent to the instruction unit 18 and used in the drawing process of the rotary shaft 5.

As shown in the example of FIG. 3, the instructing unit 18 transmits the pulling speed for each unit depth described above, so that the operator can easily operate the operating unit 23 for controlling the drive unit 4 based on it. It is composed of an image section 20 for displaying the current depth of the rotary shaft 5, an image section 21 for digitally displaying the depth for switching the drawing speed and a designated speed, an image section 22 for displaying the drawing speed with a meter, and the like. . Then, the operator operates the operation unit 23 according to the designated speed in the image unit 21.
When the pulling speed of the rotary shaft 5 is changed as specified by operating, the image unit 22 can confirm the changed speed. It should be noted that such an instruction unit 18 may give an instruction to the operator by voice or display another image. Further, technically, for example, the instruction unit 18 can be omitted by directly inputting necessary data from the arithmetic processing unit 16 to the operation unit 23 and automating the data.

(Execution example) Next, the advantages of the present invention will be made clearer while reviewing an execution example using the management device. At the time of construction work, the target ground strength and properties are grasped by preliminary tests as described above, and the amount of improvement material discharged, penetration and withdrawal speed, the number of stirring blades, the number of rotations of the stirring blades per 1 m in the depth direction. That is, the target number of blade cuts and the like are designed. The target number of blade cuts is input from the input unit 19 to the calculation program of the calculation processing unit 16. Then, the rotary shaft 5 is penetrated into or pulled out from the ground as shown in the figure while being rotated by the hydraulic motor of the drive device 4 as in the conventional case.
In these penetration and withdrawal processes, the current position of the lower end of the rotary shaft 5 is detected by the depth meter 13 and the rotational speed of the rotary shaft 5 is detected by the rotary meter 11.

In the penetration process, the improving material is discharged into the gap of the in-situ soil formed by the stirring blade 8 as described above, and is sprayed on the rotation locus along with the rotation of the stirring blade 8 to force the in-situ soil. Are mixed together. Further, as shown in FIG. 2, the number of blade cutting of the total stirring blades 8 is unit depth, that is, 0-1 m, 1-2 m, 2-3 m, 3-4 m, 4-5 m, for each unit depth of the rotary shaft 5.
And the number of insufficient blade cutting is calculated for each unit depth. In the drawing process, the operator operates the operation unit 23 according to the specified speed of the image unit 21 to proceed while adjusting and changing the drawing speed of the rotary shaft 5 for each unit depth. Therefore, in this construction management, for example, the ground is partially hard in the penetration process (the lower side of FIG. 2, a depth range of 3-4 m at the time of penetration), and the number of blade cutting in the depth part is different from that in other parts. If it becomes smaller than the above, the shortage is the number of times of blade cutting of the depth portion in the drawing process (the lower side of FIG. 2,
The range of the depth of 3-4 m at the time of pulling out) is adjusted to be larger than that of other portions, that is, the pulling speed is adjusted so that the target number of times of blade cutting is always satisfied. For this reason, the method of the present invention can sufficiently cope with the problem of the fluctuation of the rotational speed that tends to occur when the drive device 4 rotates the rotary shaft 5 by the hydraulic motor as described in the problem, and the number of blade cutting is partially insufficient. It is possible to surely eliminate the excessive or excessive work and to realize a quick and efficient construction, to evaluate whether the target number of blade cutting is satisfied for each depth, and the like.

The present invention only needs to have the technical elements specified in claims 1 to 4, and can be variously modified on the basis of the technical elements. For example, the rotating shaft 5 has a multi-axis structure,
Functions such as soil co-rotation prevention structure will be added as needed. The stirring blade 8 has a multi-stage configuration, or the blade shape is deformed. Further, the hydraulic motor described above may be one that rotates the rotary shaft 5 via a coupling mechanism, and is not limited to the mode provided above the rotary shaft 5 as in the embodiment, and for example, as shown in FIG.
It may be provided in the middle of the rotary shaft 5 like the mechanical part 12 of FIG.

[0021]

As described above, according to the present invention,
The number of blade cutting in the actual work is the sum of penetration and withdrawal, because the target number of blade cutting is surely satisfied for each predetermined depth, and since it is possible to adopt a hydraulic motor as a drive motor without problems, The construction efficiency, cost reduction and construction reliability can be further improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a method and a management device of the present invention.

FIG. 2 is a graph showing an example of a calculation result obtained by the management device of the present invention.

FIG. 3 is a schematic diagram showing an example of an image of an instruction unit in FIG.

[Explanation of symbols]

2 is a support leader 4 is a drive device (hydraulic motor, connecting mechanism) 5 is the rotation axis 8 is a stirring blade 6 is a rack member 16 is an arithmetic processing unit (arithmetic means) 17 is a display unit (display means) 18 is an instruction unit (instruction means)

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-7-158056 (JP, A) JP-A-2000-282454 (JP, A) JP-A-2000-220134 (JP, A) JP-A 64-46020 ( JP, A) JP-A-10-121460 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) E02D 3/12 102

Claims (4)

(57) [Claims] 1. A rotary shaft that is moved up and down along a support leader and is rotated by a hydraulic drive motor, and a stirring blade that is rotated integrally with the rotary shaft. While in the process of penetrating or extracting to a predetermined depth in the ground, by the stirring blade, in the ground improvement construction method of mixing the improvement material and the in-situ soil discharged into the ground, at the time of the penetration, of the rotating shaft The number of blade cutting of the stirring blade is calculated for each predetermined depth, and the difference between the calculated value and the target number of blade cutting is calculated as the number of insufficient blade cutting for each predetermined depth. A method for ground improvement construction, characterized in that the extraction speed of the rotary shaft is controlled according to the predetermined depth based on the number of times of insufficient blade cutting so as to reach the number of times of cutting. 2. The ground improvement construction method according to claim 1, wherein the rotating shaft is forcibly moved up and down via a rack and pinion mechanism attached along a support leader. 3. The ground improvement construction method according to claim 1, wherein the improvement material is discharged at least during the penetration process of the rotary shaft. 4. The method for ground improvement construction according to any one of claims 1 to 3, wherein the blade cutting frequency of the stirring blade is calculated for each predetermined depth of the rotating shaft from the rotating speed of the rotating shaft. Then, the difference between the calculated value and the target number of times of blade cutting is calculated as the number of times of insufficient blade cutting for each predetermined depth, and the extraction speed of the rotary shaft is calculated according to the predetermined depth so as to compensate for the number of times of insufficient blade cutting. A construction management apparatus comprising at least a computing means and a display means for displaying the drawing speed of the rotary shaft obtained by the computing means in association with a predetermined depth.