Method and Program for Estimating N-Value of Ground

Abstract

The purpose of the present disclosure is to estimate in a short time the N-value of a ground on which a pole is laid from the inclination and deflection of the pole before and after the placement of a load and from the load placed on the pole.　In order to achieve the above purpose, a method for estimating the N-value of a ground according to the present disclosure comprises: acquiring, before and after a load is placed on a pole laid on the ground, the displacement of a ground-level part of the pole with respect to a vertical axis and the displacement of a part of the pole 5 meters from the ground with respect to the vertical axis; calculating a coefficient of subgrade reaction from the load, the difference between the displacement of the ground-level part before the placement of the load and the displacement of the ground-level part after the placement of the load, the embedded length of the pole, the diameter of the pole, and properties of the pole; calculating a coefficient of subgrade deformation after the placement of the load from the coefficient of subgrade reaction and the diameter of the pole; calculating a coefficient of subgrade deformation before the placement of the load from the coefficient of subgrade deformation after the placement of the load and the displacement of the part of the pole 5 meters from the ground before and after the placement of the load; and estimating the N-value from the coefficient of subgrade deformation before the placement of the load and the embedded length of the pole.

Description

Technical Field

[0001] The present disclosure relates to a technique for estimating an N value representing the firmness of the ground where poles such as utility poles and signal poles are installed.

Background Art

[0002] Conventionally, the firmness of the ground when installing poles such as utility poles and signal poles has been defined by the results of a standard penetration test (JIS A 1219) called the N value. In the standard penetration test, a hammer with a mass of 63.5 kg is dropped from a height of 760 mm onto an anvil to drive an SPT (Standard Penetration Test) sampler. The N value is the number of blows required to drive the SPT sampler 300 mm (after penetration by its own weight and preliminary driving).

[0003] Based on the N value calculated by the standard penetration test, when installing a utility pole in the ground with an N value below a predetermined value, a member called a root bracing is used to install a stable utility pole even in soft ground.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0005]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, when attempting to conduct a standard penetration test during the actual installation of utility poles, it takes several hours or more to perform the test. Therefore, the necessity of root balling is determined by visual inspection to a certain extent. As a result, variations in the necessity of root balling occur depending on the experience level of the workers during pole installation. There were problems such as not performing root balling even though it was originally necessary.

[0007] In addition, in recent years, technologies (prior arts (Patent Documents 1 and 2)) have been devised to visualize the load applied to utility poles and simulate how the state of utility poles will change over time.

[0008] In such simulations, it is necessary to accurately grasp the firmness of the ground in order to estimate future states. That is, when utility poles are installed on soft ground and firm ground respectively and the same load is applied, the deformation due to the load occurs as the inclination of the pole in the former case and as the deflection of the pole in the latter case. From these facts, there is a need for a technology to simply and quickly estimate the firmness of the ground without using a simple penetration test or the like.

[0009] In order to solve the above problems, an object of the present disclosure is to estimate the N-value of the ground where a pole is installed in a short time from the inclination and deflection of the pole before and after loading and the load applied to the pole.

Means for Solving the Problems

[0010] To achieve the above object, the method for estimating the N-value of the ground according to the present disclosure is characterized by estimating the N-value of the ground from the inclination and deflection of the pole and the load applied to the pole.

[0011] Specifically, the method for estimating the N-value of the ground according to the present disclosure is Before and after loading a load on a pole laid on the ground, obtaining the displacement of the ground surface portion of the pole with respect to the vertical axis and the displacement of the 5-meter portion of the pole above the ground with respect to the vertical axis. Calculating the coefficient of subgrade reaction from the load, the difference between the displacement of the ground surface portion before loading the load and the displacement of the ground surface portion after loading the load, the embedment length of the pole, the diameter of the pole, and the characteristics of the pole. Calculating the coefficient of ground deformation after loading the load from the coefficient of subgrade reaction and the diameter of the pole. Calculating the coefficient of ground deformation before loading the load from the coefficient of ground deformation after loading the load and the displacements of the 5-meter portions above the ground before and after loading the load. Estimating the N value from the coefficient of ground deformation before loading the load and the embedment length of the pole. Perform.

[0012] Specifically, the program according to the present disclosure is a program for realizing the method for estimating the N value of the ground by a computer.

Effect of the Invention

[0013] According to the present disclosure, the N value of the ground on which the pole is laid can be estimated in a short time from the inclination and deflection of the pole before and after loading the load and the load applied to the pole.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below. These examples are merely illustrative, and the present disclosure can be implemented in various modified forms based on the knowledge of those skilled in the art. In the present specification and drawings, components having the same reference numerals indicate the same components as each other.

[0016] (Embodiment 1) An overview of a form for realizing the method for estimating the N value of the ground according to the present disclosure is shown in FIG. 1. FIG. 1 includes a laser scanner 12 for acquiring a point cloud with respect to a measurement object such as a pole 11. Here, the point cloud information acquired by the laser scanner 12 is recorded on a storage medium or the like, and the deflection and inclination of the pole are measured by an analysis device such as a PC. At the same time, the analysis device acquires the value of the horizontal load (hereinafter, the "horizontal load" is abbreviated as "horizontal load") applied to the pole 11. Then, the analysis device estimates the N value using the deflection and inclination of the pole 11 and the horizontal load.

[0017] In the present embodiment, in order to estimate the N value, a horizontal load is applied to a portion several tens of centimeters below the top of the pole 11 laid on the ground and not attached with cables or accessories, etc., and the N value is estimated using the horizontal load. To apply the horizontal load, a winch may be used for the pole 11. Further, the horizontal load may be measured using a load cell or the like. However, the present invention is not limited thereto. When estimating the N value using the pole 11 to which cables or accessories are attached, the horizontal load related to the pole 11 considering the cables and accessories currently loaded on the pole by the method described in the prior art (for example, refer to Patent Documents 1 and 2) is calculated, and the method for estimating the N value of the ground according to the present embodiment may be implemented using the calculated load. Further, when the load applied to the pole 11 is loaded in a direction other than the horizontal direction, the load is decomposed into a horizontal component and a vertical component, and the method for estimating the N value of the ground according to the present embodiment may be implemented using the horizontal component.

[0018] The above point cloud information is the result of three-dimensional measurement of the position, shape, etc. of the object to be measured by the laser scanner 12. By using the point cloud information, the pole 11 etc. can be reproduced as a 3D model.

[0019] The displacement used in the method for estimating the N value of the ground according to this embodiment will be described with reference to FIG. 2. The pole 11 shown in FIG. 2 represents the central axis of the pole 11 estimated by using the finite element method described in Patent Document 2 from the point cloud information acquired by the laser scanner 12.

[0020] In this embodiment, let the embedment length, which is the length of the part of the pole 11 buried in the ground, be l (ell). Also, let two-thirds of the length of the embedment length l of the pole 11 from the ground be represented as the depth (hereinafter, the "depth for calculating the ground deformation coefficient" will be abbreviated as "depth") Dep for calculating the ground deformation coefficient. That is, the depth Dep can be expressed as Dep = (2 / 3)l using the embedment length l. And the part of the pole 11 at the position of the depth Dep is called the rotation center O, and it is assumed that the upper part of the pole 11 inclines or deflects from the rotation center O. Therefore, in this embodiment, the vertical axis 13 is defined to pass through the rotation center O, and the displacement of the pole 11 is treated as the displacement from the axis 13, and the y-axis is taken as shown in FIG. 2.

[0021] The displacement of the pole 11 includes the displacement due to the inclination of the pole and the displacement due to the deflection of the pole. The displacement y of the 2-meter portion of the pole 11 from the ground shown in FIG. 2 02 is taken as the displacement due to the inclination. Also, the displacement y of the 5-meter portion of the pole 11 from the ground shown in FIG. 2 05 is taken as the combined displacement of the displacement due to the inclination and the displacement due to the deflection. Hereinafter, the displacement of the pole according to this embodiment will be described as the displacement y of the 5-meter portion from the ground 05 Also, as shown in FIG. 2, let the displacement of the ground contact portion of the pole (hereinafter, the "displacement of the ground contact portion of the pole" will be abbreviated as "ground contact displacement") be δ.

[0022] Hereinafter, the method for estimating the N value of the ground according to this embodiment will be described from step S101 to step S105.

[0023] (Step S101) In the method for estimating the N value of the ground according to the present embodiment, for each of the poles 11 before and after loading the horizontal load by the method described above, the point cloud information is acquired by the laser scanner 12. Then, from the acquired point cloud information, the central axis of each of the poles 11 before and after the loading of the horizontal load is estimated by the method described above. And from the central axis of each of the poles 11 before and after the loading of the horizontal load, the ground surface displacement δ before and after the loading of the horizontal load is calculated. The difference between the two calculated ground surface displacements δ is calculated as δ G.L. And then, the characteristic value β of the pole is obtained by using the formulas (1-1) to (1-4). [Number] [Number] [Number] [Number] Here, E represents the elastic modulus of the pole 11, I represents the second moment of area of the cross-section of the pole 11, H represents the horizontal load applied to the pole 11, and M represents the moment generated in the pole 11 by the horizontal load H. The elastic modulus E and the second moment of area I of the cross-section are acquired in advance from data such as the material and shape of the pole 11. Also, the horizontal load H is acquired by measurement using the load cell or the like described above, and the moment M is calculated from the horizontal load H and the distance to the portion of the pole 11 where the horizontal load H is applied.

[0024] (Step S102) The calculated characteristic value β of the pole, the diameter D of the pole 11, the elastic modulus E of the pole 11, and the second moment of area I of the cross-section of the pole 11 are used in the formula (2) to calculate the coefficient of subgrade reaction k eq And calculate it. [Number]

[0025] (Step S103) The calculated coefficient of subgrade reaction k eq and the diameter D of the pole 11 are used in Equation (3) to calculate the coefficient of ground deformation E after the application of the horizontal load H eq .

Equation

[0026] (Step S104) Using the central axes of the pole 11 before and after the application of the horizontal load H estimated in Step S101, the displacement corresponding to y shown in FIG. 2 05 is obtained. Specifically, the displacement y1 before the application of the horizontal load H is obtained from the central axis of the pole 11 before the application of the horizontal load H, and the displacement y eq after the application of the horizontal load H is obtained from the central axis of the pole 11 after the application of the horizontal load H. Then, using the displacement y1, the displacement y eq and the calculated coefficient of ground deformation E after the application of the horizontal load H eq , the coefficient of ground deformation E1 before the application of the horizontal load H is calculated using Equation (4). Note that the displacements y1 and y eq may be obtained in Step S101. y eq / y1 is called the displacement rate of the pole 11

Equation

[0027] (Step S105) Using the calculated coefficient of ground deformation E1 before the application of the horizontal load H and the depth Dep, the N value N is estimated using Equation (5).

Equation

[0028] The N-value estimation method for ground according to this embodiment may be performed simultaneously for a plurality of poles. For example, for a plurality of utility poles 11 actually installed, point cloud information of each pole 11 is obtained using a laser scanner, and the N-value estimation method for the ground is applied to each pole 11 using the point cloud information of each pole 11, whereby the N-value of the ground where each pole 11 is laid may be calculated.

[0029] For poles actually laid on soils having two types of N-values N = 7 and 17, the actually applied horizontal load H and the measured values of the inclination of the pole due to the horizontal load H, and after fixing the N-value to N = 7 and 17 respectively in Equation (5), the displacement y calculated by using the actually applied horizontal load H in Equations (1-1) to (1-4) and (2) to (5) eq (Calculated value) are shown in FIG. 3. Here, in FIG. 3, the displacement y eq is represented by converting it into an inclination. Specifically, as shown in FIG. 4, the angle formed by the straight line connecting the rotation center O and the portion where the displacement is y eq and the y-axis is defined as the inclination corresponding to the displacement y eq . From FIG. 3, it can be seen that the measured values and the calculated values of the inclination also agree well in soils with N-values of 7 and 17 respectively.

[0030] According to the present disclosure, without performing a simple penetration test that takes several hours or more for each pole, the N-value of the ground where the pole is laid can be estimated in about several minutes from the inclination and deflection of the pole before and after loading and the load applied to the pole. Further, according to the present disclosure, the N-value can be estimated for a plurality of poles simultaneously in about several minutes.

[0031] Furthermore, according to the present disclosure, a highly skilled operator can estimate the N-value without performing a simple penetration test for all poles, and can determine whether or not root piles are required without variation among operators.

[0032] In addition, for simulations of how the state of utility poles in the prior art will change in the future, by more accurately grasping the state of the ground, it is possible to obtain more accurate calculation results.

[0033] (Embodiment 2) The method for estimating the N value of the ground can also be realized by a computer and a program, and it is also possible to record the program on a recording medium or provide it through a network. FIG. 11 shows a block diagram of the system 100. The system 100 includes a computer 105 connected to a network 135.

[0034] The network 135 is a data communication network. The network 135 may be a private network or a public network, and may include any one or all of (a) a personal area network covering, for example, a certain room, (b) a local area network covering, for example, a certain building, (c) a campus area network covering, for example, a certain campus, (d) a metropolitan area network covering, for example, a certain city, (e) a wide area network covering an area that straddles the boundaries of cities, regions, or countries, or (f) the Internet. Communication is performed by electronic signals and optical signals via the network 135.

[0035] The computer 105 includes a processor 110 and a memory 115 connected to the processor 110. Although the computer 105 is represented as a stand-alone device in this specification, it is not so limited, but rather may be connected to other devices not shown in a distributed processing system.

[0036] The processor 110 is an electronic device composed of logic circuits that respond to and execute instructions.

[0037] Memory 115 is a tangible computer-readable storage medium encoded with a computer program. In this regard, memory 115 stores data and instructions, i.e., program code, that are readable and executable by processor 110 to control the operation of processor 110. Memory 115 can be implemented with a random access memory (RAM), a hard drive, a read-only memory (ROM), or a combination thereof. One of the components of memory 115 is program module 120.

[0038] Program module 120 includes instructions for controlling processor 110 to execute the processes described herein. Although operations are described herein as being performed by computer 105 or a method or process or a sub-process thereof, those operations are actually performed by processor 110.

[0039] The term "module" is used herein to refer to a functional operation that can be embodied as either a stand-alone component or an integrated configuration consisting of a plurality of sub-components. Thus, program module 120 can be implemented as a single module or as a plurality of modules operating in cooperation with each other. Further, although program module 120 is described herein as being installed in memory 115 and thus implemented in software, it can be implemented in either hardware (e.g., an electronic circuit), firmware, software, or any combination thereof.

[0040] Program module 120 is shown as already loaded into memory 115, but it may be configured to be located on storage device 140 so as to be loaded into memory 115 later. Storage device 140 is a tangible computer-readable storage medium that stores program module 120. Examples of storage device 140 include a compact disk, magnetic tape, read-only memory, optical storage medium, hard drive, or a memory unit composed of multiple parallel hard drives, as well as a universal serial bus (USB) flash drive. Alternatively, storage device 140 may be a random access memory or other type of electronic storage device located in a remote storage system (not shown) and connected to computer 105 via network 135.

[0041] System 100 further includes data sources 150A and 150B, collectively referred to herein as data source 150 and communicatively connected to network 135. In practice, data source 150 can include any number of data sources, i.e., one or more data sources. Data source 150 includes unsystematized data and can include social media.

[0042] System 100 further includes user device 130, which is operated by user 101 and connected to computer 105 via network 135. Examples of user device 130 include input devices such as a keyboard or voice recognition subsystem that enable user 101 to convey selections of information and commands to processor 110. User device 130 further includes an output device such as a display device, printer, or voice synthesizer. A cursor control unit such as a mouse, trackball, or touch-sensitive screen enables user 101 to operate a cursor on the display device to convey further selections of information and commands to processor 110.

[0043] The processor 110 outputs the result 122 of the execution of the program module 120 to the user device 130. Alternatively, the processor 110 can provide the output to a storage device 125 such as a database or a memory, for example, or can provide it to a remote device (not shown) via the network 135.

[0044] For example, the program that performs steps S101 to S105 of Embodiment 1 may be used as the program module 120. The system 100 can implement the ground N-value estimation method.

[0045] The terms "comprising" or "having" specify the presence of the features, wholes, steps, or components described therein, but are to be construed as not precluding the presence of one or more other features, wholes, steps, or components, or groups thereof. The terms "a" and "an" are indefinite articles and thus do not preclude embodiments having a plurality thereof.

[0046] (Other embodiments) Note that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. In short, the present invention is not limited to the upper embodiments as they are, and at the implementation stage, the components can be modified and embodied without departing from the gist.

[0047] Also, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined.

Industrial Applicability

[0048] The present disclosure can be applied to the communication industry and the power industry.

Explanation of Signs

[0049] 11: Pole 12: Laser Scanner 13: Vertical Axis 100: System 101: User 105: Computer 110: Processor 115: Memory 120: Program Module 122: Result 125: Storage Device 130: User Device 135: Network 140: Storage Device 150: Data Source

Claims

1. Before and after applying a horizontal load to a pole laid on the ground, obtaining the displacement of the ground surface portion of the pole with respect to the vertical axis and the displacement of the portion of the pole 5 meters above the ground with respect to the vertical axis; Calculating a coefficient of subgrade reaction from the horizontal load, the difference between the displacement of the ground surface portion before applying the horizontal load and the displacement of the ground surface portion after applying the horizontal load, the embedment length of the pole, the diameter of the pole, and the characteristic value of the pole; Calculating a coefficient of ground deformation after applying the horizontal load from the coefficient of subgrade reaction and the diameter of the pole; Calculating a coefficient of ground deformation before applying the horizontal load from the coefficient of ground deformation after applying the horizontal load and the displacements of the portion 5 meters above the ground before and after applying the horizontal load; Estimating an N value from the coefficient of ground deformation before applying the horizontal load and the embedment length of the pole; A method for estimating the N value of the ground, which performs the above steps.

2. A program for realizing the method for estimating the N value of the ground according to Claim 1 by a computer.

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