JP2021088850A - Sample acquisition system and sample acquisition method of improved ground - Google Patents

Abstract

To provide a sample acquisition system and an acquisition method for quickly acquiring a sample of an improved ground obtained by agitating and mixing a target ground and an improved material while suppressing an increase in work man-hours at a construction site.SOLUTION: A holding unit 2A constituting a sampler is placed at a standby position above each agitating blade relative to a ground improvement device in which shafts 8A... provided with agitating blades 9 are adjacent to each other and moved up and down in an upright state. Based on the plan view position of the agitating blades of the shafts 8A and 8B grasped by an agitating blade monitor unit, the control unit controls at least one rotation angle position of the shafts 8A and 8B so that the holding unit forms a moving region that can move downward without interfering with the agitating blades provided on the shafts 8A and 8B, moves the holding unit downward toward an improvement range R of a target ground B and then moves the same upward to carry out a sample acquisition step of the improved ground R, and accommodates the sample in the holding unit.SELECTED DRAWING: Figure 10

Description

The present invention relates to a sample acquisition system and a sample acquisition method for improved ground, and more specifically, a sample of improved ground obtained by stirring and mixing a target ground and an improved material is quickly produced at a construction site while suppressing an increase in work man-hours. It relates to a sample acquisition system and a sample acquisition method for improved ground that can be acquired.

A CDM (Cement Deep Mixing) method is known in which soft soil and an improving material are mixed and solidified by stirring to improve the soft ground into a solid ground. In the CDM method, a ground improvement device provided with a stirring blade that is driven to rotate is used (see, for example, Patent Document 1). The stirring blade is attached to a long rod and moves up and down in the ground. As a construction process, first, the ground is excavated to the depth of the support layer by moving the stirring blade downward in the ground while rotating the stirring blade. After that, while supplying the improved material into the ground, the stirring blade is rotated and moved upward. As a result, the improving material is injected and mixed into the ground to improve the ground.

In order to confirm the improvement condition of the constructed improved ground, it is necessary to obtain a sample of the improved ground by performing work such as driving a boring pipe into the improved ground. However, if the sample acquisition work is performed separately after the ground improvement construction, the work man-hours will increase, and the time required from the end of the construction to the acquisition of the sample will also increase. Therefore, there is room for improvement in order to quickly obtain a sample of the improved ground while suppressing the increase in work man-hours.

JP-A-2007-224645

An object of the present invention is an improved ground sample acquisition system and sample acquisition capable of quickly acquiring a sample of an improved ground in which a target ground and an improved material are agitated and mixed while suppressing an increase in work man-hours at a construction site. To provide a method.

In order to achieve the above object, the improved ground sample acquisition system of the present invention is a ground improvement device used for a ground improvement device in which a plurality of shafts equipped with stirring blades for stirring the target ground are moved up and down in an upright state. A sample acquisition system, a sampler that acquires a sample of the improved ground obtained by improving the target ground by ground improvement work using the ground improvement device, and a stirring blade monitor unit that grasps the position of the stirring blade in a plan view. Each of the stirring blades is provided with a control unit for inputting grasping data by the stirring blade monitoring unit, and a holding unit constituting the sampler is provided on at least two target shafts of the plurality of the shafts. When the sample acquisition step is performed by the sampler, the holding unit is provided on each of the target shafts by the control unit based on the grasped data. The rotation angle position of at least one of the target shafts is controlled so as to form a moving region that can move downward without interfering with the blades, and the holding portion of the standby position of the target ground by the ground improvement device is used. The sample acquisition step is performed by moving the sample downward and then moving it upward toward the improvement range, so that the sample is housed in the holding portion.

The improved ground sample acquisition method of the present invention is characterized in that the sample is acquired immediately after the ground improvement construction of the target ground by using the improved ground sample acquisition system.

According to the present invention, when the sample acquisition step by the sampler is performed by using the ground improvement device, the holding unit is each of the objects by the control unit by utilizing the grasped data by the stirring blade monitoring unit. The rotational angle position of at least one target shaft is controlled so as to form a moving region that can move downward without interfering with each of the stirring blades provided on the shaft. Therefore, the holding portion can be smoothly moved downward toward the improvement range of the target ground by the ground improvement device, and then moved upward. Then, since the sample can be accommodated in the holding portion by moving the holding portion downward and upward in the improved range, the sample can be quickly obtained while suppressing an increase in work man-hours at the construction site. ..

It is explanatory drawing which illustrates the sample acquisition system of the improved ground of this invention. It is explanatory drawing which illustrates the neighborhood of the stirring blade of FIG. 1 from the side view. FIG. 2 is a view taken along the line AA of FIG. It is explanatory drawing which illustrates the internal structure of the holding part in a vertical cross-sectional view. It is explanatory drawing which shows the internal structure of the modified example of a holding part in a vertical cross-sectional view. It is an assembly drawing which illustrates the structure of the tip part of a guide pipe. It is explanatory drawing which illustrates the process of detecting the depth position of a support layer. It is explanatory drawing which illustrates the process of discharging and mixing the improved material to the target ground. It is explanatory drawing which illustrates the position in the plan view of each stirring blade when the rotation angle position of a target shaft is controlled. It is explanatory drawing which illustrates the sample acquisition process. It is explanatory drawing which illustrates the state which the holding part which moves downward penetrates a cover material. It is explanatory drawing which illustrates the state which moved the holding part of FIG. 11 upward. It is explanatory drawing which illustrates another embodiment of this invention.

Hereinafter, the sample acquisition system and the sample acquisition method of the improved ground of the present invention will be described based on the embodiments.

The improved ground sample acquisition system 1 (hereinafter referred to as acquisition system 1) of the present invention exemplified in FIGS. 1 to 3 is applied to the ground improvement device 7 that performs ground improvement construction such as deep mixing treatment. Then, the sample S of the improved ground R improved by the ground improvement construction using the ground improvement device 7 is acquired by this acquisition system 1. In the improved ground sample acquisition method of the present invention, sample S is acquired using this acquisition system 1.

The ground improvement device 7 has a plurality of shafts 8A, 8B, 8C, 8D provided with a stirring blade 9 for stirring the target ground B. The plurality of shafts 8A to 8D are joined to each other adjacent to each other and are supported by a mast 8M extending vertically. These shafts 8A to 8D move up and down integrally along the turret 7a in an upright state. Each of the shafts 8A to 8D is rotationally driven by a drive motor 8 attached to each of the shafts 8A to 8D. Along with this, the stirring blades 9 attached to the respective shafts 8A to 8D are rotationally driven around the shaft axes of the attached shafts 8A to 8D.

The stirring blades 9 are attached to the shafts 8A to 8D at a plurality of positions spaced apart from each other in the vertical direction. A plurality of stirring blades 9 are arranged for each shaft at intervals in the circumferential direction about the shaft axis. In this embodiment, stirring blades 9 are attached to the shafts 8A to 8D at three locations with vertical intervals, and two stirring blades 9 are arranged at equal intervals in the circumferential direction at each location. Has been done. That is, six stirring blades 9 are attached to each shaft. The stirring blades 9 can be attached to each of the shafts 8A to 8D at a desired number of places, not limited to three places spaced vertically apart, and the number of stirring blades 9 arranged at each place is limited to two. The desired number can be obtained. Further, the interval in the circumferential direction of the stirring blades 9 arranged at each of the locations can also be set to a desired interval. The number of shafts 8A to 8D is not limited to four, and a desired plurality of shafts such as two, four, and eight can be used.

The stirring blades 9 of the shafts 8A to 8D arranged adjacent to each other have overlapping rotational operating ranges in a plan view centered on the axis of each shaft. The stirring blade 9, the shafts 8A to 8D, and the drive motor 8 are integrally moved up and down by winding and feeding the wire by the winch 10.

In each of the shafts 8A to 8D, a discharge port 9a is provided on the stirring blade 9 at a predetermined position (top position and bottom position in this embodiment). An improvement material C for ground improvement is supplied to the discharge port 9a from a supply tank installed on the target ground B. The discharge port 9a can be formed directly on the stirring blade 9, or one end opening of the supply pipe of the improved material C attached to the stirring blade 9 can be used as the discharge port 9a. As the improving material C, a known material is used, and specific examples thereof include cement milk.

The acquisition system 1 includes a sampler 2, a stirring blade monitoring unit 3 for grasping the position of each stirring blade 9 in a plan view, and a control unit 6 for inputting grasping data by the stirring blade monitoring unit 3. In this embodiment, a guide pipe 4 arranged above each stirring blade 9, a cover material 5 for closing the lower end opening of the guide pipe 4, and a display 6a are further provided.

As illustrated in FIG. 4, the sampler 2 has a holding portion 2A, a rod 2C connected to the upper end portion of the holding portion 2A, and a holding portion advancing / retreating mechanism 2D. In this embodiment, the sampler 2 has a tip protrusion 2B that projects downward from the lower end of the holding portion 2A.

The holding portion 2A is pulled up after being penetrated into the improved ground R by the holding portion advancing / retreating mechanism 2D, so that the sample S is housed inside. A hydraulic cylinder or the like is used for the holding portion advancing / retreating mechanism 2D. In this embodiment, the holding portion 2A of the standby position is housed in the guide pipe 4 so as to be able to advance and retreat from the lower end opening 4a of the guide pipe 4 described later.

The holding portion 2A of this embodiment has a tubular body 2a _{1 and a return member 2a 2} attached to the internal space of the tubular body 2a ₁ . The lower end of the tubular body 2a ₁ is open, and the tip protrusion 2B is fixed to a support shaft 2b extending downward from the lower end opening. In this embodiment, four triangular plate-shaped tip protrusions 2B are fixed to the support shaft 2b at equal intervals in the circumferential direction in a plan view, and project radially around the support shaft 2b.

The return member 2a ₂ is a tubular member whose lower end opening has a larger diameter than the upper end opening. The number of return members 2a ₂ may be singular, or a plurality of return members 2a 2 may be arranged at intervals in the vertical direction, and the number of arrangements can be arbitrarily set. Sample S is as shown by a broken line for example, enters the cylindrical body 2a _1, it is held between the member 2a ₂ and the cylindrical body 2a ₁ returns.

The holding portion 2A can adopt various structures capable of accommodating the sample S. For example, the holding portion 2A having the structure shown in FIG. 5 can also be used. The holding portion 2A has a dome-shaped collecting member 2a ₃ having a lower end opening and a dome-shaped receiving member 2a ₄ having an upper end opening. The lower end opening of the collecting member 2a ₃ has a larger diameter than the upper end opening of the receiving member 2a _4. A triangular plate-shaped tip protrusion 2B is fixed to the tip of a support shaft 2b extending downward from the lower end of the rod 2C.

The holding portion 2A is formed between the rod 2C and the tip protrusion 2B. The collecting member 2a ₃ and the receiving member 2a ₄ are fixed to the support shaft 2b with a vertical interval, and the lower end opening of the _{collecting member 2a 3 and the upper end opening of the receiving member 2a 4} face each other. Sample S is as shown by a broken line for example, moves downward after entering from the lower end opening of the collection member 2a _3, is held in the receiving member 2a ₄ receives enters from the upper end opening of the member 2a _4.

The position of the holding portion 2A in the plan view is set within the rotational operating range of the stirring blades 9 provided in at least two target shafts of the shafts 8A to 8D in the plan view. As illustrated in FIG. 3, in this embodiment, the position of the holding portion 2A in a plan view is set within the rotational operating range of the stirring blades 9 provided in the shafts 8A and 8B in a plan view, and is provided in the shafts 8C and 8D. It is set outside the rotational operating range of each stirring blade 9 in a plan view. Therefore, in this embodiment, the target shafts are shafts 8A and 8B.

In this embodiment, the holding portions 2A are arranged at standby positions above the stirring blades 9 of the shafts 8A to 8D, respectively, but the holding portions 2A are provided at least on the target shafts (shafts 8A and 8B), respectively. It suffices if it is arranged in the standby position above the stirring blade 9. Therefore, for example, when the position of the holding portion 2A in the plan view is set within the rotational operating range of the stirring blades 9 provided in the shafts 8A, 8B, 8C and 8D in the plan view, the holding portion 2A is a shaft. It is arranged in a standby position above each of the stirring blades 9 of 8A to 8D. The position of the holding portion 2A in the plan view is within the rotational operating range of the stirring blades 9 provided on the shafts 8C and 8D in the plan view, and the rotational operating range of the stirring blades 9 provided in the shafts 8A and 8B in the plan view. When set to the outside, the holding portion 2A is arranged in a standby position at least above the stirring blades 9 of the shafts 8C and 8D. Similarly, the guide pipe 4 may be arranged at least in a standby position above the stirring blades 9 provided on the target shafts (shafts 8A and 8B).

As the stirring blade monitor unit 3, for example, an angle sensor that detects a rotation angle (rotation angle position) about the shaft axis of each of the shafts 8A to 8D is used. In this embodiment, the positions of the stirring blades 9 provided on all the shafts 8A to 8D in a plan view are grasped. However, the stirring blades 9 for grasping the positions in a plan view are the target shafts ( In this embodiment, only the respective stirring blades 9 provided on the shafts 8A and 8B) may be used.

The guide pipe 4 is fixed to the mast 8M and extends along the respective shafts 8A to 8D. The guide pipe 4 moves up and down integrally with the respective shafts 8A to 8D.

As illustrated in FIG. 6, a cover material 5 is detachably attached to the lower end opening 4a of the guide pipe 4 by an annular flange member 4b or the like. As the cover material 5, for example, a resin film or a rubber film that is pierced by the tip protrusion 2B that moves downward together with the holding portion 2A is used.

The control unit 6 and the display 6a are connected so as to be able to communicate with each other by wire or wirelessly. The data input to the control unit 6 and the data calculated by the control unit 6 are displayed on the display 6a.

Grasp data indicating the position of each of the stirring blades 9 in a plan view grasped by the stirring blade monitoring unit 3 is sequentially input to the control unit 6. The positions of the respective shafts 8A to 8D in a plan view are known, the mounting positions of the respective stirring blades 9 on the respective shafts 8A to 8D, and the size and shape of the respective stirring blades 9 in a plan view are also known. The position of the holding portion 2A in a plan view and the size and shape of the plan view are also known. These known data are stored in the control unit 6. The control unit 6 calculates the position of each stirring blade 9 in a plan view based on the input data detected by the stirring blade monitoring unit 3 and the stored data. The control unit 6 performs various arithmetic processes based on these data.

Next, an example of the procedure for acquiring the sample S of the improved ground R by the acquisition system 1 will be described.

As illustrated in FIG. 7, the wire of the winch 10 is unwound and the respective shafts 8A to 8D are rotationally driven and moved downward as in the conventional case. As a result, the target ground B is stirred by the respective stirring blades 9 to form a stirring range Rm (range of two-dot chain line). In this step, the torque required for rotationally driving the respective shafts 8A to 8D (each stirring blade 9) and the load acting on the wires suspending the respective shafts 8A to 8D are sequentially detected. Based on these detection data, it is estimated whether or not the tips of the shafts 8A to 8D have reached the strong support layer B1.

When the above-mentioned torque becomes excessive or the above-mentioned load becomes too small, it is estimated that the tips of the shafts 8A to 8D have reached the support layer B1 and the depth position of the support layer B1 is detected. .. The depth position of the support layer B1 may be estimated by another method.

Next, as illustrated in FIG. 8, the wire of the winch 10 is wound up and the respective shafts 8A to 8D are rotationally driven and moved upward, and the improved material C is discharged from the discharge port 9a to improve the stirring range Rm. Inject material C. As a result, the earth and sand in the stirring range Rm and the improving material C are stirred and mixed.

Before discharging the improved material C from the discharge port 9a, the wire of the winch 10 is wound again and the shafts 8A to 8D are rotationally driven and moved upward to a predetermined position to move the target ground B to each position. Further stirring may be performed by the stirring blade 9. After that, the shafts 8A to 8D are rotationally driven and moved downward to the position of the support layer B1, and the improved material C can be discharged from the discharge port 9a during this downward movement.

The soft target ground B is improved to a strong improved ground R through a step of discharging the improving material C and stirring and mixing with the earth and sand in the stirring range Rm. Immediately after this ground improvement work, a sample acquisition process is carried out. Each of the shafts 8A to 8D is stopped at a depth corresponding to the position of the sample S at the desired depth to be acquired. At this time, the control unit 6 controls at least one rotation angle position of the target shafts 8A and 8B based on the grasping data grasped by the stirring blade monitor unit 3, and rotationally drives the respective shafts 8A to 8D. To stop.

More specifically, as illustrated in FIG. 9, the control unit 6 forms a moving region Z in which the holding unit 2A of the standby position can move downward without interfering with the stirring blades 9 provided on the respective target shafts 8A and 8B. The rotation angle position of the target shaft 8A, the target shaft 8B, or the target shafts 8A and 8B is controlled so as to stop the rotation. The positions of the stirring blades 9 provided on the target shafts 8A and 8B in a plan view can be visually grasped by displaying them on the display 6a.

When the positions of the stirring blades 9 provided on the target shafts 8A and 8B in a plan view are in the state illustrated in FIG. 3, the holding portion 2A in the standby position interferes with the stirring blades 9 provided on the target shafts 8A and 8B. Cannot move downward. Therefore, in the present invention, the position of the target stirring blade 9 in a plan view is grasped. It is preferable to control the rotation angle position of at least one of the target shafts 8A and 8B so that the area of the moving region Z in the plan view is maximized.

Next, as illustrated in FIG. 10, the holding portion 2A of the standby position is moved downward toward the improvement range R improved by the ground improvement device 7, and a sample acquisition step is performed. More specifically, the holding portion 2A is moved downward by pressing the rod 2C downward by the holding portion advancing / retreating mechanism 2D. As illustrated in FIG. 11, the downwardly moving holding portion 2A penetrates the cover material 5 and protrudes downward from the lower end opening 4a of the guide pipe 4 when the tip protrusion 2B penetrates the cover material 5. As a result, a through hole 5a is formed in the cover material 5. The holding portion 2A that moves further downward is inserted into the improved range R. After moving the holding portion 2A downward to a desired depth position, as illustrated in FIG. 12, the holding portion 2A is moved upward via the rod 2C by the holding portion advancing / retreating mechanism 2D and accommodated in the guide pipe 4. ..

According to this acquisition system 1, since the movement region Z is formed by controlling the rotation angle positions of the target shafts 8A and 8B, the holding portion 2A can be smoothly moved downward toward the improvement range R. Can be done. Further, in the moving region Z, even when the holding portion 2A moves upward, the holding portion 2A can smoothly move upward because it does not interfere with the stirring blades 9 provided on the target shafts 8A and 8B.

By moving the holding portion 2A downward and then upward within the improvement range R, the sample S can be accommodated in the holding portion 2A as illustrated in FIGS. 4 and 5. Therefore, at the construction site, the work using a dedicated device for acquiring the sample S again becomes unnecessary, and the sample S of the improved ground R before consolidation is quickly acquired while suppressing the increase in the work man-hours. it can.

Further, according to this acquisition system 1, the ground improvement device 7 is provided with at least a sampler 2, a stirring blade monitor unit 3, and a control unit 6 for inputting grasp data by the stirring blade monitor unit 3. Just do it. When carrying out the sample acquisition step, the rotation angle of at least one of the target shafts 8A and 8B is used so that the control unit 6 forms the above-mentioned movement region Z by using the grasped data by the stirring blade monitor unit 3. Since the position may be controlled, it is not necessary to perform complicated processing on the ground improvement device 7. It can be applied to the existing ground improvement device 7 without great difficulty.

The sample S housed inside the holding portion 2A is pulled up to the ground and then used for various analyzes. For example, the calcium content of the unconsolidated sample S is measured, and the degree of improvement of the improved ground R is evaluated based on the measurement result. Alternatively, the sample S is cured as a test piece for a uniaxial compression test, the early strength of the material age of about 1 to 3 days is measured, and the improvement condition of the improved ground R is evaluated based on the measurement result. Alternatively, the degree of improvement of the improved ground R is evaluated based on the particle size analysis of the sample S. In this way, the improvement condition of the improved ground R can be evaluated at an earlier stage, which is advantageous for feeding back to the subsequent improvement construction without delay.

In this embodiment, since the guide pipe 4 is provided, the holding portion 2A and the rod 2C are protected. Therefore, it is easy to move up and down in the target ground B and the improved ground R before the improvement without damaging the holding portion 2A.

Further, by providing the cover material 5, when the guide pipe 4 is moved downward in the target ground B or the improved ground R before the improvement, the earth and sand do not come into direct contact with the holding portion 2A, so that the holding portion 2A is protected. Is becoming more and more advantageous. Further, since the earth and sand do not enter the inside of the guide pipe 4, it is possible to prevent the holding portion 2A from being clogged in the guide pipe 4. Therefore, the holding portion 2A can be smoothly projected and moved from the guide pipe 4.

By using a resin film or a rubber film as the cover material 5, the through hole 5a of the cover material 5 formed by penetrating the holding portion 2A and the outer peripheral surface of the holding portion 2A are sealed by the cover material 5. Can be done. As a result, even after the through hole 5a is formed in the cover material 5, even if the guide pipe 4 is moved up and down in the improved ground R, it is advantageous to prevent earth and sand from entering the inside of the guide pipe 4. Become.

In the above-described embodiment, the target ground B is the land ground, but the target ground B can also be the bottom ground of the sea or rivers and lakes. In this case, as illustrated in FIG. 13, the acquisition system 1 and the ground improvement device 7 are mounted on the work boat 11 and the like. The construction procedure for forming the improved ground R and the sample acquisition step are the same as those in the previous embodiment.

1 Acquisition system 2 Sampler 2A Holding part 2a ₁ Cylindrical body 2a ₂ Return member 2a ₃ Collecting member 2a ₄ Receiving member 2B Tip protrusion 2b Support shaft 2C Rod 2D Holding part advance / retreat mechanism 3 Stirring blade monitor part 4 Guide pipe 4a Lower end opening 4b Flange member 5 Cover material 5a Through hole 6 Control unit 6a Display 7 Ground improvement device 7a Tower (leader)
8 Drive motors 8A, 8B, 8C, 8D Shaft 8M Mast 9 Stirring blade 9a Discharge port 10 winch 11 Work boat B Target ground B1 Support layer R Improvement range (improved ground)
Rm Stirring range S Improved ground sample C Improved material Z Moving area

Claims (5)

This is a sample acquisition system for improved ground used in a ground improvement device that moves a plurality of shafts equipped with stirring blades that stir the target ground up and down in an upright position.
A sampler that acquires a sample of the improved ground obtained by improving the target ground by ground improvement work using the ground improvement device, a stirring blade monitoring unit that grasps the position of the stirring blade in a plan view, and the stirring blade monitoring unit. A holding unit constituting the sampler is provided at a standby position above each of the stirring blades provided on at least two target shafts of the plurality of shafts, including a control unit for inputting grasping data. Have been placed
When the sample acquisition step by the sampler is performed, the control unit determines a moving region in which the holding unit can move downward without interfering with the stirring blade provided on each target shaft based on the grasped data. The rotational angle position of at least one target shaft is controlled so as to form.
The sample acquisition step is performed by moving the holding portion of the standby position downward toward the improvement range of the target ground by the ground improvement device and then moving upward, and the sample is transferred to the holding portion. An improved ground sample acquisition system characterized by being housed. Each of the target shafts is provided with a guide pipe that is arranged above the stirring blade and moves up and down in the improved range, and the holding portion of the standby position can be retracted from the lower end opening of the guide pipe. The improved ground sample acquisition system according to claim 1, which is housed in a guide pipe. A cover material for closing the lower end opening of the guide pipe is provided, and when the sample acquisition process is performed, the holding portion at the standby position is moved downward to penetrate the cover material and project downward from the lower end opening. Item 2. The improved ground sample acquisition system described in Item 2. According to claim 3, a resin film or a rubber film is used as the cover material, and the through hole of the cover material through which the holding portion penetrates and the outer peripheral surface of the holding portion are sealed by the cover material. Described improved ground sample acquisition system. A method for acquiring a sample of an improved ground in which the sample is acquired immediately after the ground improvement construction of the target ground by using the sample acquisition system of the improved ground according to any one of claims 1 to 4.

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