JPH0410521B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for investigating the surface properties of road pavement, and in particular, an effective and economical method suitable for investigating the properties of the pavement surfaces of a large number of roads existing in a wide area. This relates to road surface survey methods.

Road traffic volume is increasing rapidly every year. Furthermore, looking at qualitative changes in road traffic volume, the distribution of transport loads in large vehicles such as trucks is gradually increasing, which is having a major impact on pavement damage. When changes in road surface properties such as cracks, ruts, and unevenness appear on the road pavement surface, damage progresses rapidly due to the effects of traffic loads, rainwater, etc., and the usability of the pavement (drivability, safety, comfort, etc.) ) decreases rapidly.

Eventually, the pavement will need to be replaced. Maintenance and repairs must be carried out at the appropriate time; the longer the time passes, the more the costs will increase, and as the number of such lines increases, maintenance and repair costs will increase, making it impossible to carry out maintenance and repairs smoothly. Therefore, it is extremely important to carry out appropriate maintenance and repairs at the appropriate time.

In order to carry out appropriate maintenance and repair, it is necessary to conduct a road surface survey to understand the road surface properties, and based on the road surface survey, a maintenance and repair plan is formulated and the maintenance and repair is carried out.

In the maintenance and repair guidelines published by the Japan Road Association, for asphalt pavement, simple pavement, etc., the asphalt pavement surface is investigated using a measuring instrument, and then the road surface is comprehensively evaluated for each survey section or route, and the timing of maintenance and repair is determined. The serviceability index (PSI) is used to ensure that the infrastructure is not lost or to carry out maintenance and repairs from a long-term perspective based on a certain plan. Serviceability Index (PSI)
is calculated using the following formula.

PSI＝4.53−0.518 1ogσ −0.371√−0.174D ² ……(1) Here, PSI: Serviceability index σ: Standard deviation of unevenness in longitudinal direction (mm) C: Crack rate (%) D: Rutting depth average (cm) This serviceability index comprehensively evaluates the road surface and serves as a guideline for planning to find the starting order of maintenance and repair work and the approximate maintenance and repair method. The approximate corresponding methods are surface treatment for 2.1, overlay for 2 to 1.1, and replacement for 1 to 0. In addition, depending on the type and size of the damage, depending on the type of road, rutting and labeling, longitudinal unevenness, cracking rate, sliding friction coefficient, level difference,
Potholes, etc. are taken into account. Furthermore, the local environment is also taken into consideration. In addition, when conducting comprehensive evaluations based on road surface maintenance surveys, the Maintenance Management Index (MCI _o ) is used as an evaluation value to determine whether or not pavement maintenance and repair is necessary from the perspective of road managers.
It is used with. A typical formula for this maintenance management index (MIC _o ) is shown below.

MCI=10−1.48C ^0.3 −0.29D ^0.7 −0.47σ ^0.2 ...(2) Here, MCI: Maintenance index C, D, σ: Same as formula (1), except that the dimension is mm for C and D. As can be seen from the above explanation, especially from equations (1) and (2), road surface surveys can be used to calculate the standard deviation (σ) of unevenness in the longitudinal direction, the rutting rate (C), and the average rutting depth (D ) measurements.

These measurement methods currently used in road surface surveys require labor, time, and effort. For example, the crack rate can be calculated by determining the cracked area and patching area by sketching the entire survey section or by taking continuous photographs using a crack measurement vehicle, and calculating the percentage of both areas relative to the survey target section area. I'm looking for it as.
Regarding the average rut depth, the rut depth was measured every 20 m using a straight ruler or a water line, and the average was calculated. For longitudinal unevenness, use a 3m ruler with feet or a profilometer to measure at intervals of 1.5m. First, divide all measured values into groups of 6 to 10 from the beginning, and calculate the maximum of each group. After calculating the difference between the value and the minimum value, that is, the range (R), calculate the average value () of the range (R) of all groups, and divide this by a constant () depending on the number of measurements in the group. The standard deviation is calculated by dividing by _d2 ).

In addition, the conventional method may interfere with traffic during the measurement, and furthermore, there is a risk of traffic during the measurement. Therefore, it is important to automate road surface survey methods and establish simple and inexpensive road surface survey methods.
It is highly required for road maintenance.

The present invention meets these demands, and
It is simpler and more economical than conventional standard methods.
Measurement results are also obtained with values close to conventional standards, providing a versatile road surface investigation method.

That is, the survey method of the present invention is a very effective and economical method when surveying road surfaces in a wide area because it can be carried out easily and at no cost.

The feature of the road surface survey method of the present invention is the measurement of characteristic values representing road surface properties, that is, the measurement of the standard deviation of unevenness (σ), cracking rate (C), and average rutting depth (D) in the longitudinal method. Of these, the measurement of cracking rate (C) and average rutting depth (D) is extremely labor-saving.

Using the method of the present invention, we have repeatedly measured a large number of routes while comparing it with the conventional method, and have examined the measured values and the serviceability index (PSI) for road surface evaluation. It has been confirmed that it can be put into practical use.

In the road surface survey method of the present invention, a measurement route having a plurality of lanes is divided into predetermined distance intervals, and for each section, the standard deviation of unevenness in the longitudinal direction is measured for the entire length of each lane within the section. The average crack rate and rut depth were measured at one predetermined location within the section for each lane, and measured in a staggered manner so that the locations were at the same point between one lane and the other lane. The measured values for each lane shall be used as representative values for each lane in that section, and
The road surface condition of each lane in each section is evaluated from these measured values and the usability index, maintenance index, etc. calculated from these measured values, and the overall measurement lane and the measured values are evaluated from the numerical values for each section. The gist of this paper is a road surface survey method that is characterized by evaluating the road surface condition of the entire route.

Next, the road surface survey method of the present invention will be explained using figures.

The figure is for explaining the road surface survey method of the present invention.
A part of the measurement route is shown as a plan view.
The diagram shows the up lane and down lane (or left lane and right lane)
A two-lane road is taken as an example. In addition, the illustration shows that the direction in which the road extends is extremely shortened. In the figure, 1 is the measurement route, 2 is the up lane (or left lane), and 3 is the down lane (or right lane). 4,
4... are dividing lines that divide the measurement route 1 at predetermined distance intervals, and the area between these dividing lines 4 is defined as one section L, which is the unit of measurement. 5 is the measurement line for measuring the standard deviation (σ) of unevenness in the longitudinal direction, 6 is the measurement position for measuring the rut ratio (C), and 7 is the measurement position for measuring the rutting depth (D). It shows.

The distance of section L can be determined relatively freely, but it is generally 50 to 300 m, usually 100 to 200 m.
If you shorten the distance by 50 meters, it will approach and eventually match the conventional standard method. It can be done even if you strain for 300m.
However, if the distance is too long, the accuracy will deteriorate, so it is best to keep it within a maximum of 500 meters.

The road surface inspection method of the present invention will be explained using the up lane 2 in the figure as an example.

The standard deviation (σ) of unevenness in the longitudinal direction is measured on the measurement line 5 for each section L ₁ , L ₂ , . . . _Lo . In the figure, σ ₁ is in interval L ₁ , σ 3 is in interval L ₂ , and σ ₃ is in interval L 1.
σ _2o-1 corresponds to L _o . The position of the measurement line 5 and the measurement method conform to the asphalt pavement guidelines (implemented by the Japan Road Association). As for the measurement method, various methods can be adopted. For example, it is possible to use a method in which a profilometer is towed in a car and measured while driving, a method in which a vibration meter is loaded in a car and measured while driving, and a correlation with vibration is measured. The crack rate (C) is investigated at measurement position 6 at the tip of section L. C ₁ corresponds to section L ₁ , and C ₃ corresponds to section L ₂ . Measurement of crack rate (C) is as follows:
The sketch method or the photographing method using a road photographing vehicle is used. Taking the latter as an example, take a photograph of an area of approximately 5 m in the lane direction (lane width m x 5 m) across the full width of the lane, and measure the cracking rate (C) from this photograph.
This measured cracking rate C ₁ is taken as a value representing the cracking rate (C) of the section L ₁ . The average rut depth (D) is measured at measurement position 7 at the beginning of section L. Measuring rut depth is
It is measured by the water string method, ruler method, and other methods that use laser beams. Of course crack rate (C)
The average rutting depth (D) and the average rut depth (D) may be at any position as long as they are in the section L to which they belong, but the distance to the measurement position in the next section L is between dividing lines 4 and 4. It is preferable to make the distance equal to the distance . The position shown in the figure seems to be the most preferable position for data processing. This measured average rutting depth D ₁
Let be the average rutting depth (D) representing the section L ₁ with .

In this way, for each section L ₁ , L ₂ , ...L _o ,
Standard deviation of unevenness in each longitudinal direction (σ),
Once the cracking rate (C) and average rutting depth (D) are measured, the serviceability index (PSI) and maintenance management index (MCI) for each section L are calculated from these values for each section L. be done. The road surface condition of the entire measurement lane is evaluated from the standard deviation (σ) of unevenness in the longitudinal direction of each section, crack rate (C), average rut depth (D), serviceability index (PSI), etc. be able to.

Now, if we compare the conventional standard method with the case where the length of section L is 100 m in the above, the measurement area of the crack rate (C) is 1/20, and the measurement of the average rutting depth (D) is 1/5. (Normally, this is done once every 20m in the conventional standard method), which is extremely labor-saving compared to the conventional standard method. The Serviceability Index (PSI) etc. are then calculated from these values.

The standard deviation (σ) of the unevenness in the longitudinal direction measured by this method, the cracking rate (C), and the average rutting depth (D) are the same as those measured by the conventional standard method. Not only the standard deviation (σ) but also the cracking rate (C) and the average rutting depth (D) have a very good correlation and are well within a practical range. The same applies to the serviceability index (PSI) calculated from these three characteristic values.

Next, a road surface survey method for two lanes, upper and lower, will be explained. Average standard deviation of unevenness (σ), cracking rate (C), and rutting depth in the longitudinal direction of each lane
Measurement (D) is performed in the same way as the previous measurement of one lane, but in a staggered manner with the measurement positions of up lane 2 and down lane 3 being different.
Therefore, the accuracy of road surface quality evaluation is further improved than when measuring one lane.

The measuring method, measuring position, etc. for the up lane 2 on one side are as described above. Down lane 3
The measurement method for the two lanes is also the same, but the measurement position is shifted from the measurement position for the up lane 2. The standard deviation (σ) of unevenness in the longitudinal direction is measured on the measurement line 5 of the up lane 2 and the measurement line 5 at the target position, and is calculated in the corresponding longitudinal direction for each section L, L ₂ , ... _Lo Standard deviation of unevenness σ ₂ , σ ₄ ,…
Measure σ _2o . Measurement position 6 of crack rate (C) is
It should be located between the measurement position 6 of the same section L1 of the up lane ₂ and the measurement position 6 of the next section _L2 . In the diagram, it is exactly at the halfway point. This crack rate (C) is measured and taken as a representative value for the downbound lane 3 of that section L.
The crack rate C ₂ corresponds to the section L ₁ of the down lane 3. Measurement position 7 of the average rutting depth (D) is also the same as the case of cracking rate (C), upbound lane 2.
It is set at the midpoint between the measured values of 7 and 7. The measured value is representative of the interval L. An average rutting depth D ₂ corresponds to the section L ₁ . In this way, the standard deviation of unevenness (σ), cracking rate (C), and average rutting depth (D) in the longitudinal direction for down lane 3 are measured for each section, and the values for each section L are calculated from the respective values. Calculate serviceability index (PSI) and maintenance management index (MCI).

The evaluation of the road surface properties of the measured route is determined for each section L from the measured values of the up lane 2 and the down lane 3, and the calculated values therefrom. Generally, the serviceability index (PSI) of the up lane 2 and the down lane 3 of each section L are compared, and the lower serviceability index value is taken as the serviceability index value of that section L, and the unevenness in the longitudinal direction of that section is determined. Standard deviation (σ), crack rate (C),
For the average rut depth (D), etc., values for lanes that use serviceability index values are used. Standard deviation of unevenness (σ) in the longitudinal direction of the section L, crack rate (C)
When extracting the average rut depth (D) independently, it is also possible to use the average value of both lanes.
It is also possible to adopt a lower value. In addition, regarding the serviceability index (PSI), the standard deviation (σ) of unevenness in the longitudinal direction of both lanes, the crack rate
(C), the average value of the average rut depth (D) or the standard deviation of the unevenness in the longitudinal direction of the lower lane (σ);
It is calculated from the cracking rate (C) and the average rutting depth (D), and this is sometimes used as the serviceability index (PSI) for section L. These evaluation methods can be easily calculated by incorporating them into a computer program once the policy has been determined. The road surface condition of the measured route can be evaluated from each characteristic value and serviceability index (PSI) measured for each section L ₁ , L ₂ , ... _Lo .

Even when the measurement route has three lanes or four lanes, the road surface properties of two representative lanes can be evaluated in the same manner as for the two lanes described above.

The road surface investigation method of the present invention employs a method that is extremely labor-saving compared to conventional standard methods. However, when comparing and examining a large number of routes (including those with the same level of traffic volume, serviceability index, etc., as well as those with different numbers), we found that the correlation was very good, and that the conventional standard method Almost the same measurement value is obtained, and it is sufficiently usable for practical use. The reason why such high accuracy of measurement values can be obtained is that if the measurement line is set within an appropriate range, the subgrade soil is often uniform and the bearing capacity is the same. If the government office that has jurisdiction over the route is the same, the designed structure will be the same. Traffic volume is also constant. Furthermore, the construction companies that build pavements are the same for each district, the pavement materials used are also the same, and the construction techniques are also the same. Additionally, traffic volume, weather conditions, and roadside environments are often similar. Therefore, the condition of the pavement is often uniform between about 50 and 300 meters.
If a change is observed, the road surface properties in that section can be made more uniform by shortening the distance between the divided sections. For this reason, it is thought that reasonable measurement results can be obtained even if the cracking rate (C) and the average rutting depth (D) are extremely labor-saving. In addition, the method of the present invention measures the standard deviation (σ) of unevenness in the longitudinal direction without omitting the section, so the flatness can be checked by checking the road surface condition of the section in the same way as before. We are doing our best to make it possible.

The feature of the road surface investigation method of the present invention is that the measurement line is divided into many sections, and the crack rate (C) is evaluated at one point at an appropriate position within each section to evaluate the road surface properties of each section. Measurements are taken on a small area and the measured values are used to represent the cracking rate (C) of each section, and the average rutting depth (D) is measured at one appropriate location within each section. The measured value is used to represent the average rutting depth (D) of each section, and the standard deviation (σ) of longitudinal unevenness is measured without labor saving for each section, and this is the measurement that represents the section. The serviceability index (PSI) etc. are calculated from these measured values, and the road surface condition of the section is evaluated from these characteristic values, and furthermore, the road surface condition of the entire measured route is evaluated. On routes with two or more lanes, the two lanes are measured in the same way, but the measurement positions of the two lanes are measured at staggered positions so that the measurement results of the two lanes are complementary to each other. Furthermore, a simple method has been developed for measuring the standard deviation (σ) of unevenness in the longitudinal direction, and these can also be used.

The road surface investigation method of the present invention is simpler than conventional standard methods and can significantly save labor, time, cost, etc. It is also very beneficial for traffic safety.

The measured or calculated characteristic values are obtained for each section, and the road surface condition of that section is evaluated.The road surface condition of the route is evaluated based on the evaluation of these sections. The accuracy of the evaluation is very close to that obtained using the conventional standard method. It has excellent benefits such as:

With such features and effects, the road surface survey method of the present invention is a very effective method as a road surface survey method for smoothly and accurately maintaining and managing road pavement. By using this, it is possible to understand the road surface condition without requiring much effort, cost, or time. Therefore, it is particularly suitable as a road surface survey method for a wide area.

[Brief explanation of drawings]

The figure shows a plan view of a portion of the measurement route to illustrate the road surface survey method of the present invention. In the figure, 1 is the measurement route, 2 is the up lane (left lane), 3 is the down lane (right lane), 4 is the marking line, and 5
is the measurement line for measuring the standard deviation (σ) of unevenness in the longitudinal direction, 6 is the measurement position of cracking rate (C), and 7 is the measurement position of rutting depth (D).

Claims (1)

[Claims] 1. Divide the measurement route with multiple lanes into predetermined distance intervals, and for each section, measure the standard deviation of unevenness in the longitudinal direction for the entire length of each lane section, and calculate the cracking rate and rut depth. The average height of each lane is measured at one predetermined point within the section of each lane in a staggered manner so that the position is at a point where one lane and the other lane are staggered. These measured values are used to represent each lane in that section, and the road surface condition of each lane in each section is calculated from these measured values and the serviceability index and maintenance index calculated from these measured values. A road surface investigation method characterized by evaluating the road surface properties of the entire measurement lane and the entire measurement route from the numerical values of each section.