Noise reduction effect evaluation method for existing road sound barrier

Abstract

The invention discloses a noise reduction effect evaluation method for an existing road sound barrier, and solves the problems of large workload, high cost, low accuracy and large test difficulty caused by the fact that insertion loss depends on field actual measurement in the prior art. Comprising the following steps: selecting evaluation indexes including a normal included angle between a receiving point and a section of a road surface road center line, a coverage degree of the height of a sound barrier at the receiving point to a road, a linear distance between the receiving point and the road surface road center line, and a distance between the receiving point and the nearest end part of the sound barrier; based on the evaluation indexes, constructing a data matrix, performing regression analysis in combination with a least square method in a mode of solving a non-zero solution through a non-homogeneous overdetermined equation, and fitting to obtain an evaluation formula of the insertion loss of the sound barrier; and calculating a sound barrier insertion loss value according to an evaluation formula as a quantitative index of the noise reduction effect. According to the method for rapidly and accurately evaluating the noise reduction effect of the road sound barrier through the environmental parameters and the engineering indexes, the field workload is reduced, and the accuracy and convenience are improved.

Description

Technical Field

[0001] The present invention relates to the fields of environmental noise control and road engineering, and particularly relates to a method for evaluating the noise reduction effect of existing road sound barriers. Background Art

[0002] As a core facility for controlling road traffic noise, sound barriers are widely used in scenarios such as urban roads, highways, and rail transit, effectively reducing the propagation of noise to sensitive areas through physical isolation. Currently, the evaluation of the noise reduction effect of sound barriers in the industry mainly relies on standards such as the "Code for Acoustic Design and Measurement of Sound Barriers" (HJ / T90-2004), which requires quantifying its performance by measuring the insertion loss (IL) in the field. The insertion loss is defined as the difference in the noise level at the receiving point before and after the installation of the sound barrier, which is the core index for evaluating the noise reduction effect. However, the on-site measurement of the insertion loss is limited by the actual engineering environment, the equivalence of the reference point and the receiving point before and after the installation of the sound barrier is poor, the investment in funds and time is high, the difficulty of measuring the insertion loss is large, and the accuracy is low.

[0003] Therefore, it is necessary to find a more convenient and accurate method to quickly and accurately evaluate the noise reduction effect of road sound barriers through environmental parameters and engineering indicators. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for evaluating the noise reduction effect of existing road sound barriers, so as to solve the technical problems of large workload, high cost, low accuracy, and large test difficulty caused by relying on on-site measurement of insertion loss in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions: A method for evaluating the noise reduction effect of existing road sound barriers provided by the present invention includes the following steps: Step 1: Select evaluation indicators, and the evaluation indicators include: the normal angle between the receiving point and the cross-section of the road center line of the road surface, the coverage of the sound barrier height at the receiving point on the road, the straight-line distance between the receiving point and the road center line of the road surface, and the distance between the receiving point and the nearest end of the sound barrier; Step 2: Based on the evaluation indicators, construct a data matrix, and through the method of finding the non-zero solution of the non-homogeneous overdetermined equation and combining the least squares method for regression analysis and function fitting, obtain the evaluation formula for the insertion loss of the sound barrier; Step 3: Calculate the insertion loss value of the sound barrier according to the evaluation formula as a quantitative index for the noise reduction effect.

[0006] Further, the calculation formula for the normal angle is: When the receiving point is lower than the road surface: θ = 90 + arctg ( ); When the receiving point is higher than the road surface: θ = 90 - arctg( ); where h1 is the height of the receiving point, in m; h2 is the height of the roadbed, in m; L0 is the horizontal distance from the receiving point to the center of the road, in m.

[0007] Furthermore, the coverage of the sound barrier for the road is the product of the following three indicators: the coverage of the sound barrier height for the lane , the coverage of the sound barrier length for the road , and the coverage affected by the holes in the barrier body , and the expression for the coverage is: ; where: L1 is the coverage width of the sound barrier height corresponding to the receiving point for the road surface, in m; L is the road surface width, in m; d1 is the length of the sound barrier, in m; d2 is the distance from the receiving point to the sound barrier, in m; d3 is the distance from the receiving point to the nearest end of the sound barrier, in m; d4 is the length of the sensitive point along the road direction, in m; S is the area of the sound barrier, in m 2 ; S1 is the area of the holes on the sound barrier, in m 2 ; a is the coefficient of the sound barrier shielding angle to ensure that the noise reduction effect remains 80% after the finite length correction of the sound barrier.

[0008] Furthermore, the specific steps of step 2 include the following steps: Select 4 independent variables, namely the center distance , the normal angle , the coverage , and the distance to the nearest end point ; Formulate the relationship between the insertion loss of the sound barrier and the 4 independent variables: ; ; where, is the insertion loss value of the sound barrier at the i-th time, the dependent variable, in dB; is the correlation coefficient of the independent variable center distance at the i-th time, in m; is the correlation coefficient of the independent variable normal angle at the i-th time, in degrees; is the correlation coefficient of the independent variable coverage at the i-th time, in %; is the correlation coefficient of the independent variable distance to the nearest end point at the i-th time, in m; is the coefficient corresponding to each of the four independent variables after fitting, abbreviated as: ; where, , , this is a non-homogeneous overdetermined equation; By constructing a least - squares problem to find a non - zero solution, perform singular value decomposition on A, and obtain: , Simplify to: , D is the diagonal matrix corresponding to the eigenvalues after the singular value decomposition of matrix A; ; Obtain: ; That is is what is sought; Based on the measured data matrix, the calculation formula for the insertion loss of the sound barrier obtained by quadratic regression is: , is the existing insertion loss of the sound barrier, dB.

[0009] Based on the above - mentioned technical solution, the embodiments of the present invention can at least produce the following technical effects: The method for evaluating the noise reduction effect of the existing road sound barrier provided by the present invention, by selecting key evaluation indicators and constructing a data matrix, combining non - homogeneous over - determined equations and the least - squares method for regression analysis and function fitting, can quickly and accurately calculate the insertion loss value of the sound barrier, as a quantitative index for the noise reduction effect. This method significantly reduces the on - site workload, reduces the evaluation cost and difficulty, and at the same time improves the accuracy and convenience of the evaluation. It is applicable to various scenarios such as urban roads, highways, and rail transit, and provides an efficient and reliable solution for the evaluation of the noise reduction effect of sound barriers. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0011] Figure 1 It is a schematic diagram of the normal angle θ between the receiving point A of the present invention and the cross - section of the road center line of the road surface; Figure 2 It is the coverage of the sound barrier height on the lane of the present invention Schematic diagram; Figure 3 It is the coverage of the sound barrier length on the road of the present invention Schematic diagram; Figure 4 It is the coverage affected by the holes in the screen body of the present invention Schematic diagram; Figure 5 It is a modified diagram of the finite - length sound barrier and line source of the present invention; Figure 6 It is a schematic diagram of the straight - line distance ρ between the receiving point A of the present invention and the center line of the road surface; Figure 7 It is a schematic diagram of the distance d3 between the receiving point A of the present invention and the end of the sound barrier; Figure 8 It is a comparison diagram of the calculated value and the measured value of the present invention. Detailed implementation manners

[0012] Next, the technical solutions in the embodiments of the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0013] A method for evaluating the noise reduction effect of an existing road sound barrier includes the following steps: Step 1: Select 4 key evaluation indexes in the cylindrical coordinate dimension; In this embodiment, the 4 key evaluation indexes include: ① The normal angle θ between the receiving point and the cross - section of the center line of the road surface. As Figure 1 shown, the larger this normal angle, the better the noise reduction effect. The calculation formula for the normal angle is: When the receiving point is lower than the road surface: θ = 90 + arctg( ); When the receiving point is higher than the road surface: θ = 90 - arctg( ); where h1 is the height of the receiving point, in m; h2 is the height of the roadbed, in m; L0 is the horizontal distance from the receiving point to the center of the road, in m.

[0014] ② The coverage of the sound barrier on the road at the receiving point , and the coverage of the sound barrier on the road is the product of the following three indexes, as shown in Figure 2 , Figure 3 and Figure 4 shown respectively: the coverage of the sound barrier height on the lane , the coverage of the sound barrier length on the road , the coverage affected by the holes in the screen body .

[0015] That is, the expression for the coverage of the sound barrier on the road at the receiving point is: ; where: L1 is the coverage width of the height of the sound barrier corresponding to the receiving point on the road surface, in m; L is the road surface width, in m; d1 is the length of the sound barrier, in m; d2 is the distance from the receiving point to the sound barrier, in m; d3 is the distance from the receiving point to the nearest end of the sound barrier, in m; d4 is the length of the sensitive point along the road direction, in m; S is the area of the sound barrier, in m 2 ; S1 is the area of the holes on the sound barrier, in m 2 ; a is the coefficient of the shielding angle of the sound barrier that ensures the noise reduction effect remains 80% after the finite length correction of the sound barrier; In this embodiment, as Figure 5 shown, after calculation Figure 5 the β angle in .

[0016] It has been demonstrated that the greater the coverage of the sound barrier on the road at the receiving point, the better the noise reduction effect.

[0017] ③ The straight-line distance ρ between the receiving point and the center line of the road surface, as Figure 6 shown, its calculation formula is as follows: ; h1 is the height of the receiving point, in m; h2 is the height of the roadbed, in m; L0 is the horizontal distance from the receiving point to the center of the road, in m.

[0018] ④ The distance d3 between the receiving point and the nearest end of the sound barrier, as Figure 7 shown.

[0019] Step 2: Use a large number of measured data to form a data matrix and fit an evaluation formula for the insertion loss of the sound barrier; Specifically, the method of finding the non-zero solution of a non-homogeneous overdetermined equation and the least squares method are used for regression analysis and function fitting to obtain the formula for the insertion loss of the sound barrier and 4 independent variables (key indicators). Step 2 specifically includes the following steps: Select 4 independent variables, which are the center distance , the normal angle , the coverage , and the distance to the nearest end point ; List the relationship between the insertion loss of the sound barrier and the 4 independent variables: ; ; where, is the insertion loss value of the i-th sound barrier, the dependent variable, dB; is the correlation coefficient of the center distance of the independent variable for the i-th time, m; is the correlation coefficient of the normal angle of the independent variable for the i-th time, degree; is the correlation coefficient of the coverage of the independent variable for the i-th time, %; is the correlation coefficient of the distance of the nearest end point of the independent variable for the i-th time, m; are the coefficients corresponding to the four independent variables after fitting, abbreviated as: ; Among them, , , this is a non-homogeneous overdetermined equation; By constructing a least squares problem to find a non-zero solution and performing a singular value decomposition on A, we get: , Simplified to: , D is the diagonal matrix corresponding to the eigenvalues after the singular value decomposition of matrix A; ; Obtained: ; That is is what we want.

[0020] Based on the measured data matrix, the calculation formula for the insertion loss of the sound barrier obtained by quadratic regression is: , is the existing insertion loss of the sound barrier, dB.

[0021] Step 3: Calculate the insertion loss value of the sound barrier according to the evaluation formula as a quantitative index of the noise reduction effect. The comparison chart of the calculated value and the measured value after calculation is as shown in Figure 8 shown.

[0022] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the noise reduction effect of an existing road sound barrier, characterized in that, Including the following steps: Step 1: Select evaluation indicators, which include: the normal angle between the receiving point and the cross-section of the road center line of the road surface, the coverage of the height of the sound barrier at the receiving point to the road, the straight-line distance between the receiving point and the road center line of the road surface, and the distance between the receiving point and the nearest end of the sound barrier; Step 2: Based on the evaluation indicators, construct a data matrix, and through the method of finding the non-zero solution of the non-homogeneous overdetermined equation and combining the least squares method for regression analysis and function fitting, obtain the evaluation formula for the insertion loss of the sound barrier; Step 3: Calculate the insertion loss value of the sound barrier according to the evaluation formula as the quantization index of the noise reduction effect.

2. The method for evaluating the noise reduction effect of an existing road sound barrier according to claim 1, characterized in that The calculation formula for the normal angle is: When the receiving point is below the road surface: θ = 90 + arctg ( ); When the receiving point is higher than the road surface: θ = 90 - arctg ( ); where h1 is the height of the receiving point, in m; h2 is the height of the roadbed, in m; and L0 is the horizontal distance from the receiving point to the center of the road, in m.

3. The method for evaluating the noise reduction effect of the existing road sound barrier according to claim 1, characterized in that The coverage of the sound barrier on the road is the product of the following three indicators: the coverage of the sound barrier height on the lane , the coverage of the sound barrier length on the road , and the coverage affected by the holes in the screen body , and the expression of the coverage is: ； Where: L1 is the coverage width of the height of the sound barrier corresponding to the receiving point on the road surface, in m; L is the road surface width, in m; d1 is the length of the sound barrier, in m; d2 is the distance from the receiving point to the sound barrier, in m; d3 is the distance from the receiving point to the nearest end of the sound barrier, in m; d4 is the length of the sensitive point along the road direction, in m; S is the area of the sound barrier, in m 2 ; S1 is the area of the holes on the sound barrier, in m 2 ; a is the coefficient of the shielding angle of the sound barrier to ensure that the noise reduction effect remains 80% after the finite length correction of the sound barrier.

4. The method for evaluating the noise reduction effect of an existing road sound barrier according to claim 1, characterized in that, The specific steps of Step 2 include the following steps: Select four independent variables, namely the straight-line distance between the receiving point and the road center line of the road , the normal angle between the receiving point and the cross-section of the road center line , the coverage of the height of the sound barrier at the receiving point on the road , the distance between the receiving point and the nearest end of the sound barrier ; Formulate the relationship between the insertion loss of the sound barrier and 4 independent variables: ； ； Among them, is the insertion loss value of the sound barrier at the i-th time, the dependent variable, dB; is the correlation coefficient of the center distance of the independent variable at the i-th time, m; is the correlation coefficient of the normal angle of the independent variable at the i-th time, degree; is the correlation coefficient of the coverage of the independent variable at the i-th time, %; is the correlation coefficient of the distance of the nearest endpoint of the independent variable at the i-th time, m; are the coefficients corresponding to the four independent variables after fitting, abbreviated as: ； Among them, , , this is a non-homogeneous overdetermined equation; By constructing a least squares problem to find the non-zero solution and performing singular value decomposition on A, we get: ， Simplified to: , D is the diagonal matrix corresponding to the eigenvalues after the singular value decomposition of matrix A; ； Obtained: ; That is is what is sought; Based on the measured data matrix, the calculation formula for the insertion loss of the sound barrier obtained by quadratic regression is: ， IL is the insertion loss of the existing sound barrier, in dB.

Images