Method for checking condition of surrounding ground in compaction method

Abstract

To enable accurate and easy confirmation of the state of the ground around a compacted improved body when the compacted improved body is constructed in the ground.SOLUTION: A method for checking a condition of surrounding ground in a compaction method comprises a first photographing step of photographing a condition of the ground before a construction of a compaction improvement body, a second photographing step of photographing the condition of the ground after the construction of the compaction improvement body, an image processing step of converting the images of the condition of the ground before the construction of the compaction improvement body and the images of the condition of the ground after the construction of the compaction improvement body into binary images, and a confirmation step of calculating the proportion of the area of gaps in the ground in each of the converted binary images from each of the converted binary images, and comparing the proportions of the area of gaps in the ground in each of the calculated binary images to check the condition of the ground surrounding the constructed compaction improvement body to see if it has been compacted as planned.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for confirming the condition of the surrounding ground in a compaction method in which a compaction improvement body is created in the ground and the surrounding ground is compacted, and the method confirms the condition of the surrounding ground of the compaction improvement body that has been created. [Background technology]

[0002] The compaction method for improving ground is a method in which granular materials such as sand and crushed stone, or materials obtained by adding cement or a fluidizing agent to these granular materials, are injected into the ground or discharged into the ground and then driven back in to create a compacted improved body in the ground, and the surrounding ground is compacted by the creation of this compacted improved body. For example, the sand compaction pile method, in which granular materials such as sand and crushed stone are discharged into the ground and the discharged granular materials are driven back in to create an expanded compacted improved body in the ground, and the surrounding ground of the created compacted improved body is improved to be strong, and the compaction grouting method, in which mortar with extremely low fluidity is injected into the ground to compact the surrounding ground (Patent Document 1), are known as examples of this compaction method.

[0003] The ground improvement equipment used in the compaction method is equipped with a construction casing pipe with a mast erected at the front. The construction machine penetrates the casing pipe into the ground or pulls it out from the ground. The casing pipe is cylindrical and has a supply passage inside for granular materials such as sand and crushed stone, and a discharge port at the bottom from which the granular materials are discharged into the ground.

[0004] The compaction method involves penetrating a casing pipe into the ground to a specified depth, pulling out the casing pipe a specified length while discharging the granular material, and then driving back the granular material that was discharged by penetrating the casing pipe a specified length. This discharge of the granular material and the driving back of the granular material by the casing pipe are repeated upwards. This creates a compaction improvement body with an expanded diameter in the ground, and the surrounding ground can be improved to a solid ground with a specified density.

[0005] In the compaction method, after constructing a compaction improvement body in the ground, the condition of the surrounding ground of the compaction improvement body is checked to see if it has a predetermined density, that is, whether the surrounding ground of the compaction improvement body has been compacted as planned. This checking method is performed by commonly known standard penetration tests and sounding tests.

[0006] When the condition of the ground surrounding a constructed compacted improvement body is checked using a standard penetration test, the condition of the surrounding ground can only be checked approximately every 1 m in the depth direction. Furthermore, this check involves comparing the N-value obtained from the standard penetration test before the construction of the compacted improvement body with the N-value after the construction of the compacted improvement body, and the increase in the density of the ground surrounding the compacted improvement body is estimated from the increase in N-value, and this allows the condition of the surrounding ground to be checked to see whether it has reached the specified density.

[0007] However, since the condition of the surrounding ground can only be checked approximately every 1m in the depth direction, it is not possible to check the condition of the surrounding ground in detail, and since the density of the ground around the compacted improvement body is not measured directly, the accuracy of checking the condition of the surrounding ground is poor. This causes a problem that it is difficult for workers to accurately determine whether the ground around the constructed compacted improvement body has been compacted as planned. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 8-284146 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of such problems, and its object is to provide a method for confirming the surrounding ground condition in a compaction method, which can accurately and easily confirm whether the surrounding ground condition of a compaction improvement body created in the ground has reached a specified density, i.e., whether the surrounding ground has been compacted as planned. [Means for solving the problem]

[0010] The present invention is a method for confirming the condition of the surrounding ground in a compaction method in which a granular material such as sand or crushed stone or a material obtained by adding cement or a fluidizing agent to the granular material is pressed into the ground or discharged into the ground and then driven back in, and the surrounding ground is compacted by the creation of the compaction improvement body. The method includes a first photographing step of photographing the condition of the ground before the creation of the compaction improvement body, a second photographing step of photographing the condition of the ground after the creation of the compaction improvement body, and a predetermined image processing program is used to confirm the condition of the surrounding ground of the compaction improvement body from the image of the condition of the ground before the creation of the compaction improvement body photographed in the first photographing step and the image of the condition of the ground after the creation of the compaction improvement body photographed in the second photographing step. This method for checking the surrounding ground condition in a compaction method comprises: an image processing step of converting an image into a binary image of the condition of the ground before construction of the compaction improvement body and a binary image of the condition of the ground after construction of the compaction improvement body; and a confirmation step of calculating the percentage of the area of ​​gaps in the ground in the binary image from the binary image of the condition of the ground before construction of the compaction improvement body and the binary image of the condition of the ground after construction of the compaction improvement body converted in the image processing step, and comparing the percentage of the area of ​​gaps in the ground in the calculated binary image of the condition of the ground before the construction of the compaction improvement body with the calculated percentage of the area of ​​gaps in the binary image of the condition of the ground after construction of the compaction improvement body to check whether the ground around the compaction improvement body has been compacted as planned. Effect of the Invention

[0011] According to the present invention, it is possible to confirm the condition of the surrounding ground when the compaction improvement body is constructed, whether the surrounding ground of the compaction improvement body has been compacted as planned, from the photographs of the ground before and after the construction of the compaction improvement body. This makes it possible to check the surrounding ground condition in detail in the depth direction, and furthermore, by directly checking the surrounding ground condition (density) of the compaction improvement body, it is possible to increase the accuracy of checking the surrounding ground condition of the compaction improvement body. Therefore, the worker can easily and accurately determine whether the surrounding ground of the compaction improvement body has been compacted as planned. [Brief description of the drawings]

[0012] [Figure 1] 1 is a side view of a ground condition inspection device used in a method for inspecting surrounding ground conditions in a compaction method of the present invention. FIG. [Diagram 2] 2A and 2B are diagrams showing a tip cone of a ground condition monitoring device, in which FIG. 2A is a front view of the tip cone and FIG. 2B is a vertical cross-sectional view of the tip cone. [Diagram 3] FIG. 2 is a flow diagram of a method for checking the surrounding ground conditions using the compaction method of the present invention. [Figure 4] FIG. 4A is a diagram showing a binary image of the state of the ground before the construction of a compacted and improved body, and FIG. 4B is a diagram showing a binary image of the state of the ground after the construction of a compacted and improved body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of a method for checking surrounding ground conditions in a compaction method of the present invention will be described with reference to the drawings. The method for checking the surrounding ground conditions in the compaction method according to this embodiment is a method for checking whether the surrounding ground conditions of a compacted improvement body (also called a "compacted sand pile" in the sand compaction pile method) has reached a specified density when the compacted improvement body is constructed in the ground by the sand compaction pile method or the like, in other words, whether the surrounding ground conditions of the compacted improvement body have been compacted as planned. The surrounding ground here refers to the ground between adjacent compacted improvement bodies when multiple compacted improvement bodies have been constructed, or at a point a specified distance away from the constructed compacted improvement body. The method of checking the surrounding ground conditions in the compaction method of the present invention is not limited to the sand compaction pile method, but can also be used in other compaction methods in which granular materials such as sand or crushed stone, or materials made by adding cement or a fluidizing agent to these granular materials, are pressed into the ground or discharged into the ground and then driven back in to create a compaction improvement body in the ground, and the surrounding ground is compacted by creating the compaction improvement body.

[0014] A ground condition checking device 1 used in a method for checking surrounding ground conditions in a compaction method will be described. Fig. 1 is a side view of a ground condition monitoring device 1 used in a method for monitoring surrounding ground conditions in a compaction method. Fig. 2 is a diagram of the tip cone of the ground condition monitoring device 1, Fig. 2A is a front view of the tip cone, and Fig. 2B is a vertical cross-sectional view of the tip cone. As shown in Figure 1, the ground condition inspection device 1 comprises a rod 2 that penetrates the ground, a tip cone 3 attached to the tip (lower end) of the rod 2 and carrying a video camera 31, and a processing device 4 that performs various processing tasks.

[0015] The rod 2 has a cylindrical tubular shape that extends vertically, and is penetrated into or pulled out of the ground by the construction machine 5. The construction machine 5 is self-propelled, has a mast 51 erected at its front, and the rod 2 is positioned along this mast 51. The rod 2 is penetrated into or pulled out of the ground by a penetration device 52 provided in the construction machine 5. Note that the construction machine 5 is not limited to this, and a construction machine for a ground improvement device used in a compaction method may also be used.

[0016] As shown in Figures 2A and 2B, the tip cone 3 is attached to the tip (lower end) of the rod 2 and penetrates into the ground, and has a cylindrical tubular shape that faces up and down. The tip cone 3 is equipped with a video camera 31 that captures images of the ground. An opening 32 for filming is opened on the side of the tip cone, and the video camera 31 is placed inside this opening 32. By pointing the video camera 31 in a direction perpendicular to the axial direction of the tip cone 3, it is possible to film the state of the ground during penetration or extraction. Note that, although there is only one opening 32 and video camera 31 provided in the tip cone 3 here, there may be multiple openings 32 and video cameras 31.

[0017] The processing device 4 is a computer that stores various programs and performs various processing operations using the stored programs. The processing device 4 receives and stores images of the state of the ground before and after the construction of the compacted improvement body taken by the video camera 31. Next, each stored image is converted into a binary image using a specified image processing program. At the same time, the area ratio of the gaps in the ground in each binary image of the state of the ground before and after the construction of the compacted improvement body is calculated, and the calculated area ratio of the gaps in the binary image of the state of the ground before and after the construction of the compacted improvement body is compared with the calculated area ratio of the gaps in the binary image of the state of the ground after the construction of the compacted improvement body.

[0018] The processing device 4 is mounted on a construction machine 5 that performs the work of penetrating or extracting the rod 2 and the tip cone 3 into the ground. However, the present invention is not limited to this, and the processing device 4 may be installed in an office at the work site or in a different location, such as within the premises of a construction company.

[0019] Next, the method for checking the surrounding ground conditions when using the compaction method will be explained using the flow chart in Figure 3. The method of checking the surrounding ground conditions in the compaction method includes a first photographing step (S1) of photographing the state of the ground before the construction of the compaction improvement body at the time of penetration or extraction, a second photographing step (S2) of photographing the state of the ground after the construction of the compaction improvement body at the time of penetration or extraction, an image processing step (S3) of converting the image of the state of the ground before the construction of the compaction improvement body photographed in the first photographing step (S1) and the image of the state of the ground after the construction of the compaction improvement body photographed in the second photographing step (S2) into a binary image, and and a confirmation process (S4) in which the condition of the ground surrounding the created compaction improvement body is confirmed by calculating the percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the creation of the compaction improvement body and the percentage of the area of ​​gaps in the ground in the binary image of the ground condition after the creation of the calculated compaction improvement body from the binary image of the ground condition after the creation of the compaction improvement body, and comparing the percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the creation of the compaction improvement body with the percentage of the area of ​​gaps in the ground in the binary image of the ground condition after the creation of the compaction improvement body.

[0020] [First photography process] The first photographing step (S1) is a step in which, before constructing a compaction improvement body in the ground, the rod 2 and the tip cone 3 are penetrated into the ground by the construction machine 5, and the state of the ground at this time is photographed by the video camera 31 mounted on the tip cone 3. The state of the ground photographed by this video camera 31 is a color video image. Furthermore, the state of the ground is photographed when the rod 2 and the tip cone 3 are penetrating into the ground, but the state of the ground may also be photographed when the rod 2 and the tip cone 3 are pulled out after they have penetrated into the ground, that is, when they are pulled out.

[0021] [Second shooting process] The second photographing step (S2) is a step in which, after constructing the compacted improvement body in the ground, the rod 2 and the tip cone 3 are penetrated into the ground by the construction machine 5, and the state of the ground around the compacted improvement body at the time of penetration is photographed by the video camera 31 mounted on the tip cone 3. The state of the ground photographed by the video camera 31 is a moving color image. The state of the ground is photographed when the rod 2 and the tip cone 3 are penetrating into the ground, but the state of the ground around the compacted improvement body may be photographed when the rod 2 and the tip cone 3 are pulled out after penetrating into the ground, that is, when they are pulled out. In this second photographing step (S2), the point at which the rod 2 and the tip cone 3 are penetrated into the ground is between adjacent compacted improvement bodies when multiple compacted improvement bodies are constructed, or at a point a predetermined distance away from the constructed compacted improvement body. In addition, in the first photographing process (S1) and the second photographing process (S2), the video camera 31 may photograph the entire depthwise length of the compacted improved body being constructed, or it may only photograph the necessary area, for example, in a stratum containing a mixture of sand and clay layers, where the sand layer is, for example, 5 to 10 m deep, the range from 5 to 10 m deep may be photographed.

[0022] [Image processing process] The image processing step (S3) is a step of converting into a binary image the image of the ground condition before the construction of the compacted and improved body taken in the first photographing step (S1) and the image of the ground condition after the construction of the compacted and improved body taken in the second photographing step (S2). This operation is performed by the processing device 4 using a specified image processing program.

[0023] A binary image is an image that is represented in two colors, black and white. In this conversion to a binary image, a color image captured by a video camera 31 is first converted to a grayscale image using a predetermined program. This grayscale image is an image that expresses black and white shading, for example, one pixel is 8 bits, and in this 8-bit image, the shading is expressed in 256 gradations, with a pixel value of 0 being black, and the color gradually becoming lighter from there, with a pixel value of 255 being white. Next, in the pixel values ​​of the converted grayscale image, if the pixel value is equal to or greater than a set threshold, it is converted to white W, and if it is less than the threshold, it is converted to black B, thereby making it possible to convert the image into a binary image expressed in two colors, white W and black B. The threshold is set to a value that allows particles such as soil and sand in the ground to be expressed as white W, and gaps in the ground to be expressed as black B, respectively. This binarized image is shown, for example, in Figures 4A and 4B. Figure 4A is a binarized image of the state of the ground before the construction of the compaction improvement body, and Figure 4B is a binarized image of the state of the ground after the construction of the compaction improvement body.

[0024] [Confirmation process] The confirmation step (S4) is a step in which the proportion of the area of ​​gaps in the ground in each of the binary images of the ground condition before the construction of the compaction improvement body, which have been converted in the image processing step (S3), and the binary image of the ground condition after the construction of the compaction improvement body are calculated, and these are compared to confirm the condition of the surrounding ground of whether it has been compacted as planned. The comparison of the proportion of the area of ​​gaps in the ground in the binary images of the ground condition before the construction of the compaction improvement body and the ground condition after the construction of the compaction improvement body is performed for the same depth. Furthermore, these operations are performed by the processing device 4 using a specified processing program.

[0025] Specifically, from a binary image of the condition of the ground before the construction of the compaction improvement body, the proportion of the area of ​​gaps in the ground in that binary image (the area of ​​black B) is calculated, and at the same time, from a binary image of the condition of the ground after the construction of the compaction improvement body, the proportion of the area of ​​gaps in the ground in that binary image (the area of ​​black B) is calculated.

[0026] Next, the calculated percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the construction of the compaction improvement body is compared with the calculated percentage of the area of ​​gaps in the ground in the binary image of the ground condition after the construction of the compaction improvement body, and the reduction rate of the percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the construction of the compaction improvement body and the binary image of the ground condition after the construction of the compaction improvement body is determined. This reduction rate indicates the extent to which the proportion of the area of ​​gaps in the ground (area of ​​black B) in the binary image of the ground condition before and after the construction of the compaction improvement body has decreased between before and after the construction of the compaction improvement body.

[0027] Next, the condition of the surrounding ground to determine whether it has been compacted as planned is confirmed by checking the reduction rate of the area ratio of gaps in the ground in a binary image of the ground condition before the construction of the compaction improvement body and a binary image of the ground condition after the construction of the compaction improvement body, and by checking whether the reduction rate exceeds a predetermined value.

[0028] That is, if the rate of decrease in the percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the construction of the compaction improvement body and the binary image of the ground condition after the construction of the compaction improvement body exceeds a predetermined value, it is understood that the area of ​​gaps in the ground (gaps in the ground) has decreased and the particulate part of the ground such as soil and sand has increased, that is, the density of the particles of soil and sand has increased and the specified density has been reached, and the ground around the compaction improvement body has been compacted as planned. On the other hand, if the rate of decrease in the percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the construction of the compaction improvement body and the binary image of the ground condition after the construction of the compaction improvement body is below a predetermined value, it is understood that the decrease in the area of ​​gaps in the ground (gaps in the ground) is small and the increase in the particulate part of the ground such as soil and sand is small, that is, the increase in the density of the particles of soil and sand is small, the specified density has not been reached, and the ground around the compaction improvement body has not been compacted as planned. As described above, it is possible to check the condition of the surrounding ground to see whether the ground around the compaction improvement body has been compacted as planned. The predetermined value for the rate of change here is a value determined in the design for the compaction method.

[0029] As described above, according to this embodiment, it is possible to check whether the surrounding ground condition of the compacted improvement body when it is constructed has a predetermined density, that is, whether it has been compacted as planned, from the state of the ground before the construction of the compacted improvement body and the state of the ground after the construction of the compacted improvement body, which are photographed at the time of penetration or extraction. This makes it possible to check the surrounding ground condition in detail in the depth direction, and furthermore, by being able to directly check the surrounding ground condition of the compacted improvement body, it is possible to increase the accuracy of checking the surrounding ground condition of the compacted improvement body. Therefore, the worker can easily and accurately determine whether the surrounding ground of the compacted improvement body has been compacted as planned. [Explanation of symbols]

[0030] 1...ground condition inspection device, 2...rod, 3...tip cone, 31...video camera, 32...opening, 4...processing device, 5...construction machine, 51...mast, 52...penetration device

Claims

1. A method for confirming the condition of the surrounding ground in a compaction method in which granular materials such as sand or crushed stone, or materials to which cement or a fluidizing agent has been added, are injected into the ground or discharged into the ground and then driven back in, thereby creating a compaction improvement body in the ground, and the surrounding ground is compacted by creating the compaction improvement body, the method comprising: A first photographing step of photographing the state of the ground before the construction of the compaction improvement body; A second photographing step of photographing the state of the ground after the compaction improvement body is created; an image processing step of converting the image of the ground condition before the construction of the compaction improvement body taken in the first photographing step and the image of the ground condition after the construction of the compaction improvement body taken in the second photographing step into a binary image of the ground condition before the construction of the compaction improvement body and a binary image of the ground condition after the construction of the compaction improvement body using a specified image processing program; a confirmation process in which the percentage of the area of ​​gaps in the ground in each of the binary images of the ground condition before the construction of the compaction improvement body converted in the image processing process and the binary image of the ground condition after the construction of the compaction improvement body are calculated, and the percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the construction of the compaction improvement body is compared with the percentage of the area of ​​gaps in the binary image of the ground condition after the construction of the compaction improvement body to confirm whether the surrounding ground condition of the compaction improvement body has been compacted as planned; A method for checking surrounding ground conditions using a compaction method, comprising:

2. In the method for checking the surrounding ground condition in the compaction method described in claim 1, This method for checking the surrounding ground conditions in a compaction method is characterized in that the confirmation process compares the calculated percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the construction of the compaction improvement body with the calculated percentage of the area of ​​gaps in the ground in the binary image of the ground condition after the construction of the compaction improvement body, determines the reduction rate of the percentage of the area of ​​gaps in the ground in the binary image of the ground condition before the construction of the compaction improvement body and the binary image of the ground condition after the construction of the compaction improvement body, and checks the condition of the ground surrounding the constructed compaction improvement body based on whether the reduction rate exceeds a predetermined value.

Images