CN105628518A - Method for detecting and evaluating compaction uniformity of inorganic stabilized granular base course of road - Google Patents

Abstract

The invention discloses a method for detecting and evaluating the compaction uniformity of an inorganic stabilized granular base course of a road. According to a detection point arrangement principle, the Evdi of a to-be-estimated section of the road is detected by adopting a PFWD (Portable Falling Weight Deflectometer); a detection result is subjected to statistic analysis, so as to obtain a deformation modulus average value and a variance; upper and lower confidence limits are calculated; the three-dimensional curved surface of Evd is cut; value lines of the Evd and the like are projected out; the area Sh of a qualified region and the area Sq of an overall region are calculated; a uniformity index t is calculated according to a definition; the compaction uniformity is estimated according to an evaluation standard; a judgment method of a compacted weak region of a roadbed is to define the compacted weak region of the roadbed by adopting an Evd lower confidence region of the to-be-detected section of the road; the quick aftercompaction can be carried out according to the position of the weak region.

Description

Road inorganic stabilizers pellet class basic unit compacting homogeneity methods of testing and evaluating

Technical field

The invention belongs to road engineering material Performance Detection and control of construction quality technical field, it relates to a kind of method of the test and repair of road inorganic stabilizers pellet class basic unit compacting homogeneity.

Background technology

Regulation in existing " highway road surface operating technique detailed rules and regulations " (JTGF20-2015), road engineering stabilized with inorganic binder pellet class basic unit (cement stabilized macadam, cement stabilizing gravel, fly ash lime stabilized crushed rock and Three_kind ash gravels) compaction quality detection adopt fill with sand method, the frequency of detection is every 200 meters of every tracks 2 place, and every 200 meters of every tracks 2 place obtains data sample very little, the A+E of compacting homogeneity cannot be used at all, if increasing pattern detection frequency, add the ununiformity of final compaction quality on the contrary, because filling with sand method is damage detection, point after detection cannot return to the state before compacting.

And fill with sand method and there is following shortcoming:

(1) requiring great effort consuming time, instant directive significance is not enough

When diameter of testing pits is 20cm, average detected 30-35Min/ point consuming time, instructs compacting with this detected result, has serious hysteresis quality;

(2) artifical influence factor is many, and precision is not high

Compaction detect result is had a significant impact by the human factors such as the mode of the moist situation of standard sand, the precision of demarcation, the shape that compaction detect is tested pits and moisture determination, it is difficult to ensure objectivity.

(3) damaging detection, range of value is little

The cutting ring of the 5cm that compactness of subbase detection is tested pits from inorganic stabilizers fine grained soil, joins the filling sand method of 10cm, develops into the filling sand method of the 15-20cm of current skeleton-thick grading to closely knit suspension level, and volume progressively expands, and is a kind of damage to the basic unit of compaction moulding.

Therefore, electrodeless stable granulate class basic unit adopts fills with sand method and detects its compacting situation, cannot obtain highdensity data sample, and the homogeneity of basic unit's compacting is evaluated by the detection data that this method cannot be adopted to obtain. Simultaneously, the homogeneity of roadbase compacting is not proposed detecting and assessing method by road industry, more not proposing the evaluation index of homogeneity, roadbase only detects 6-10 point with every kilometer and evaluates construction quality, and the data that there is a small sample are to evaluate the sorry of integral construction quality.

Summary of the invention

It is an object of the invention to provide the methods of testing and evaluating of a kind of road pellet class base material compaction quality homogeneity, in road inorganic stabilizers pellet class road base construction quality control process, realize the system of compaction quality, fast, nondestructively evaluate, the evaluation based on " point " is changed to the evaluation based on " face ".

It is an object of the invention to be achieved through the following technical solutions:

A kind of road inorganic stabilizers pellet class basic unit compacting homogeneity methods of testing and evaluating, comprises the steps:

(1) section that construction compacting is good is carried out PFWD (portable falling weight deflectometer) detection, obtain the Evd of different check point_i, calculate the modulus of deformation mean value Evd and variance S of evaluation section, draw the three-dimension curved surface of each check point planimetric position and Evd;

(2) according to the statistic analysis result of Evd, calculating the upper and lower confidence limit of modulus of deformation Evd, above lower confidence limit is that the three-dimension curved surface of Evd is cut by reference plane, and projects out Evd isopleth, calculates the area S in qualified region_h, all zones area S_q, uniformity coefficient t;

(3) evaluation criteria of homogeneity is as follows: t >=90% is assessed as excellent, and 75%��t < 90% is assessed as good, and during 60%��t < 75% is assessed as, t < 60% is assessed as difference;

(4) decision method of subgrade compaction weak area is definition subgrade compaction weak region in confidence district under the Evd adopting and being detected section, carries out quick ftercompction according to the position of weak area.

Tool of the present invention has the following advantages:

1, in existing " highway road surface operating technique detailed rules and regulations ", pellet class (soap-free emulsion polymeization class or inorganic binder bonding class) is not had not have evaluation index and the evaluation method of compaction quality homogeneity, the defining method more not having compaction quality weak area, it is blank that the present invention has filled up industry;

2, the method has harmless, feature fast, it is not necessary to digs pit, can not shaping basic unit be destroyed.

3, the method has objective feature, and the display of detected result scene and printing, avoid artificial interference data.

4, the method has needs that personnel are few, efficiency height, save single-point testing cost.

Accompanying drawing explanation

The subgrade compaction Evaluation for Uniformity that Fig. 1 is half range (two grades) or 1/4 width (at a high speed, one-level) for detection section detects point layout figure;

The subgrade compaction Evaluation for Uniformity that Fig. 2 is full width (two grades) or half range (at a high speed, one-level) for detection section detects point layout figure;

Fig. 3 is compacting homogeneity qualified (grey) and defective region (white) contrast;

Fig. 4 is between roadbase compacting weak area (gray zone).

Embodiment

Below in conjunction with accompanying drawing, the technical scheme of the present invention is further described; but it is not limited thereto; every technical solution of the present invention modified or equivalent replaces, and not departing from the spirit and scope of technical solution of the present invention, all should be encompassed in protection scope of the present invention.

The present invention provides a kind of road inorganic stabilizers pellet class basic unit compacting uniformity evaluating method, by being the modulus of deformation value Evd adopting portable falling weight deflectometer (PFWD) detection to be compacted section, detection data are carried out statistical study, according to the confidence limit up and down calculated, the three-dimension curved surface of Evd is cut, and project out Evd isopleth, calculate the area S in qualified region_hWith all zones area S_q, according to definition, calculate uniformity coefficient index t, according to evaluation criteria, the homogeneity of compacting evaluated; The decision method of subgrade compaction weak area is definition subgrade compaction weak region in confidence district under the Evd adopting and being detected section, according to the position of weak area, it is possible to carry out quick ftercompction.

It is below the concrete implementation step of technical scheme:

In road engineering, owing to traditional filling sand method required time is long, structure there is is damage, a large amount of data gatherings can not be carried out, cannot the homogeneity of Subgrade Compaction quality evaluate. And use PFWD can carry out a large amount of data gatherings, thus realize the evaluation to compacting homogeneity. The method that use PFWD carries out compacting homogeneity test and repair is as follows:

(1) section is selected and point layout

1. the selection in section

When carrying out basic unit's compacting Evaluation for Uniformity, evaluate survey section and immediately follow the tracks of construction detection section, section to be checked after may also be work, the evaluation length in instant tracing detection section can be the construction length of a day, can also be the road section length of a certain construction organization, or filling material change before road section length; For section to be checked after work, it should choose filling material change before road section length, and keep survey segment length at 500��1000m.

2. the layout of measuring point

The decoration form of measuring point selects a transverse section along route direction every 20m, when detect section be two grades and two grades to get down the highway time, when half range detect, each optimal crosssection 3 point, when full width detect, general layout 5 points on each section; It is motorway or during one-level road when detecting section, when 1/4 width detects, each optimal crosssection 3 point, when half range detect, general layout 5 points on each section. Point layout figure is as shown in Figure 1-2.

(2) PFWD gathers and base conditioning

During data gathering, the rigidity base plate of PFWD fully must contact with road bed, keeps with the contact form in " face ", mustn't occur coming to nothing, the state on warp and some basis, if desired, fine sand can be adopted to make up road bed space, make measured surface smooth solid; Vertical free state must be kept, and the height that falls meets requirement when dropping hammer. Collection result is carried out preliminary treatment, rejects the data not meeting statistics and requiring, and determine to detect the parameters such as the sample number of data, average, standard deviation.

(3) evaluation of homogeneity

The coordinate of institute's measuring point and corresponding Evd value are write in Matlab program, set up the Evd distribution plan of each measuring point in roadbed plane, cutting is gone again by the plane that the allowed Evd relevant with measuring point number with degree of confidence is corresponding, defective region can be obtained, show that this region Evd value and other regions Evd value have big difference, as adopted upper and lower fiducial interval as reference plane, calculation formula is as shown in (1):

$E\stackrel{\&OverBar;}{v}d-t_{\frac{a}{2}}(n-1)\frac{s}{\sqrt{n}}\&le;Evd\&le;E\stackrel{\&OverBar;}{v}d+t_{\frac{a}{2}}(n-1)\frac{s}{\sqrt{n}}---\left(1\right).$

In formula:The mean value (Mpa) of each measuring point compactness in test evaluation section;

t_a/2With counting and guarantee rate and the coefficient that becomes in t-distribution table, tabling look-up draws;

The standard deviation of S detected value;

N detection is counted.

According to the confidence limit up and down calculated, being cut by the three-dimension curved surface of Evd, and project out Evd isopleth, calculate area and all zones area in qualified region, as shown in Figure 3, grey is qualified region area, and by (2) formula uniformity coefficient:

$t=\frac{s_h}{s_q}\&times;100\%---\left(2\right).$

In formula: t uniformity coefficient (%);

S_hQualified region area, namely Evd meets the area corresponding to formula (1);

S_qAll zones area, namely evaluates the total area in section.

And draft following evaluation criteria: t >=90% is assessed as excellent, and 75%��t < 90% is assessed as good, and during 60%��t < 75% is assessed as, t < 60% is assessed as difference.

(4) judgement of subgrade compaction weak area

The weak region of subgrade compaction refers to that the compactness in this region or the index of modulus of deformation do not meet requirement, by the ftercompction of street roller, the compactness of roadbed or the region of modulus of deformation can be improved, the weak region of subgrade compaction adopts lower fiducial interval to determine, it is determined that formula is as shown in (3):

$Evd\&le;\stackrel{\&OverBar;}{E}vd-t_{\frac{a}{2}}(n-1)\frac{s}{\sqrt{n}}---\left(3\right).$

In formula:The mean value (Mpa) of each measuring point compactness in test evaluation section;

t_a/2With counting and guarantee rate and the coefficient that becomes in t-distribution table, tabling look-up draws;

The standard deviation of S detected value;

N detection is counted;

By the transformation in the weak region of Subgrade Compaction and ftercompction, it is possible to improve the degree of uniformity of subgrade construction, reduce the non-uniform settling of roadbed. Fig. 4 is gray zone is roadbase compacting weak area.

Claims (5)

1. a road inorganic stabilizers pellet class basic unit compacting homogeneity methods of testing and evaluating, it is characterised in that described method steps is as follows:

(1) section that construction compacting is good is carried out PFWD detection, obtain the Evd of different check point_i, calculate the modulus of deformation mean value Evd and variance S of evaluation section, draw the three-dimension curved surface of each check point planimetric position and Evd;

(2) according to the statistic analysis result of Evd, calculating the upper and lower confidence limit of modulus of deformation Evd, above lower confidence limit is that the three-dimension curved surface of Evd is cut by reference plane, and projects out Evd isopleth, calculates the area S in qualified region_h, all zones area S_q, uniformity coefficient t;

(3) evaluation criteria of homogeneity is as follows: t >=90% is assessed as excellent, and 75%��t < 90% is assessed as good, and during 60%��t < 75% is assessed as, t < 60% is assessed as difference;

(4) decision method of subgrade compaction weak area is definition subgrade compaction weak region in confidence district under the Evd adopting and being detected section, carries out quick ftercompction according to the position of weak area.

2. road according to claim 1 inorganic stabilizers pellet class basic unit compacting homogeneity methods of testing and evaluating, it is characterized in that in described step (1), the decoration form of check point is: select a transverse section along route direction every 20m, when detect section be two grades and two grades to get down the highway time, when half range detects, each optimal crosssection 3 point, when full width detects, general layout 5 points on each section; It is motorway or during one-level road when detecting section, when 1/4 width detects, each optimal crosssection 3 point, when half range detect, general layout 5 points on each section.

3. road according to claim 1 inorganic stabilizers pellet class basic unit compacting homogeneity methods of testing and evaluating, it is characterised in that in described step (2), the calculation formula of the upper and lower confidence limit of modulus of deformation Evd is as follows:

$\stackrel{-}{Evd}-t_{\frac{a}{2}}(n-1)\frac{s}{\sqrt{n}}\&le;Evd\&le;\stackrel{-}{Evd}+t_{\frac{a}{2}}(n-1)\frac{s}{\sqrt{n}},$

In formula:The mean value of each measuring point compactness in test evaluation section, Mpa;

t_a/2With counting and guarantee rate and the coefficient that becomes in t-distribution table;

The standard deviation of S detected value;

N detection is counted.

4. road according to claim 1 inorganic stabilizers pellet class basic unit compacting homogeneity methods of testing and evaluating, it is characterised in that in described step (2), the calculation formula of uniformity coefficient t is as follows:

$t=\frac{s_h}{s_q}\&times;100\%.$

5. road according to claim 1 inorganic stabilizers pellet class basic unit compacting homogeneity methods of testing and evaluating, it is characterised in that in described step (4), the determination formula in the weak region of compacting is as follows:

$Evd\&le;\stackrel{\&OverBar;}{E}vd-t_{\frac{a}{2}}(n-1)\frac{s}{\sqrt{n}},$

In formula:The mean value of each measuring point compactness in test evaluation section, Mpa;

t_a/2With counting and guarantee rate and the coefficient that becomes in t-distribution table;

The standard deviation of S detected value;

N detection is counted.