CN103628457A - Method for rapidly detecting foundation soil compactness by using penetrometer - Google Patents

Abstract

The invention discloses a method for rapidly detecting foundation soil compactness by using a penetrometer, and relates to the technical field of compactness detection. The method comprises the following steps: I, randomly selecting 18-25 fill construction fields, selecting a foundation soil region to be detected, extracting a test sample to be detected, and sending to a test room for performing compaction test to obtain the maximum dry density of the test sample; II, detecting the penetration resistance value of the foundation soil area to be detected which is treated in the step I on site by using a penetration resistance instrument; III, acquiring a unary regression equation of penetration resistance value-dry density, wherein a formula of the unary regression equation is Y=(aX)+b, wherein Y is dry density*10, X is the penetration resistance value, and a and b are regression coefficients; IV, detecting the penetration resistance value of the foundation soil, and introducing the penetration resistance value acquired by detecting into the unary regression equation obtained in the step III to obtain the dry density of the foundation soil of a fill construction fields. The method has the advantages of simple principle, accurate and efficient data testing and capability of accurately guiding field construction.

Description

A kind of method of using penetrometer fast detecting foundation soil degree of compaction

Technical field

The present invention relates to a kind of method for quick of foundation soil degree of compaction, more particularly, relate to a kind of method of using penetrometer fast detecting foundation soil degree of compaction.

Background technology

Ground is the basic structure on ground, is the basis of supporting earth construction, with the effect of the common bearing load in ground, bears erosion and the impact of climate change and various natural calamities simultaneously.The stress-strain characteristics of ground plays an important role to the bulk strength of earth construction and rigidity.In the distortion of earth construction, the distortion of ground accounts for 70%～90%.Ground is general employing placement in layers, compacting in work progress, disguise is stronger, as packing quality is not good or construction control is improper, be easy to cause ground to fill of poor quality, thereby cause very easily causing a series of disease, as crack, depression and wave etc., have a strong impact on quality and the life-span on ground, and processing to ground disease often needs to excavate whole road structure, maintenance cost is very high, has caused the loss of a large amount of manpower and materials.Therefore, strictly control foundation quality most important.

Foundation soil degree of compaction is one of key index of subgrade and pavement detection of construction quality, characterizes the density situation after on-the-spot compacting, and degree of compaction is higher, and density is larger, and material monolithic performance is better.Foundation soil degree of compaction is all with core cutter method, the method for sealing with wax, douche or sand replacement method, to sample at the scene Hou Dao test room to dry sample and claim sample to obtain dry density to draw testing result divided by maximum dry density all the time.These method ubiquities detection times is long, accuracy is not high, plant and instrument complicated operation, shortcoming that testing cost is high, testing result out at least needs 24 hours, result lags behind programming out time far away, even if find that detection index is satisfied or have problem, which floor on-the-spot embankment covered already, and the workmanship of job site has been lost to directive significance.Therefore, studying a kind of detection methods of compaction degree of foundation soil fast and is accurately the current task of top priority.

Through retrieval, Chinese Patent Application No. 200910030903.3, the applying date is on April 17th, 2009, invention and created name is: method for detecting compacting quality of roadbed, this application case comprises the following steps: that step 1 bores penetrometer (DCP) in the standard injection of test point by power, layering detects a cubic metre of earth injection rate PR for roadbed section DCP test (mm/ of unit hammering time, gets hammering numerical value conventionally a time); Step 2 is according to the injection rate PR of single measuring point DCP test, calculate the banket weighted average NPR of injection rate of every layer of this measuring point, and then obtain CBR value or modulus of resilience E: step 3 is judged supporting capacity and the integrated carrying ability of the different depth of this place's roadbed according to CBR value or the modulus of resilience.Although this application case has shortened the time that Subgrade Compaction Quality detects to a certain extent, the detection method of this application case is more complicated, is not easy to promote.

Summary of the invention

1. the technical problem that invention will solve

Frequency is large, detection speed is slow, the slow problem that affects programming of testing result because detecting to the object of the invention is to solve job site foundation soil degree of compaction, a kind of method of using penetrometer fast detecting foundation soil degree of compaction is provided, use one group of sample of detection method of the present invention can obtain a result in 10～15 minutes, can provide rapidly data, guide field construction exactly.

2. technical scheme

For achieving the above object, technical scheme provided by the invention is:

A kind of method of using penetrometer fast detecting foundation soil degree of compaction of the present invention, its concrete steps are:

Step 1, in target detection geographic coverage, choose at random 18～25 embankment job sites, in embankment job site, choose at random a slice foundation soil to be detected region, at described foundation soil extracted region to be detected sample to be detected, to test room, do compaction test and obtain sample maximum dry density and optimum moisture content;

The penetration resistance value in foundation soil to be detected region described in step 2, use injection resistance meter Site Detection step 1;

Step 3, the penetration resistance value of utilizing maximum dry density that step 1 obtains and step 2 to obtain, obtain penetration resistance value-dry density regression equation with one unknown, and the formula of this regression equation with one unknown is: Y=aX+b; In formula, Y is dry density * 10, and X is penetration resistance value, and a, b are regression coefficient, is a definite value;

Foundation soil penetration resistance value is detected in step 4, the embankment job site in target detection geographic coverage described in step 1, and the penetration resistance value that detection is obtained is brought the regression equation with one unknown that step 3 obtains into, draws the dry density of this embankment job site foundation soil.

Further, the concrete operation step of step 1 acquisition maximum dry density and optimum moisture content is:

(1) by quartering, get sample 20kg to be detected, the air-dry 5mm round hole screen that pulverized, mixes the lower soil sample of sieve thoroughly, and measures the air-dry moisture content of sample to be detected; According to native plastic limit, estimate optimum moisture content, prepare the sample of 5 different water cuts, the moisture content difference of adjacent 2 samples is 2%, and these 5 samples light-dutyly hit real sample as one group;

(2) by quartering, get sample 50kg to be detected, the air-dry 20mm sieve that pulverized, mixes the lower soil sample of sieve thoroughly, and measures the air-dry moisture content of sample to be detected; According to native plastic limit, estimate optimum moisture content, prepare the sample of 5 different water cuts, the moisture content difference of adjacent 2 samples is 2%, and these 5 samples hit real sample as one group of heavy type;

(3) the light-duty heavy type of hitting real sample and step (2) acquisition respectively step (1) being obtained is hit real sample and is done compaction test, calculates the wet density of sample;

(4) according to following formula, calculate the dry density of sample:

in formula: the dry density that ρ d is sample, get 0.01g/cm ³; The wet density that ρ 0 is sample, gets 0.01g/cm ³; ω i is the moisture content of sample, gets 0.1%;

(5) draw the relation curve of dry density and moisture content, ordinate represents sample dry density, abscissa represents sample moisture content, and the corresponding ordinate of described relation curve peak point is the maximum dry density of sample to be detected, and corresponding abscissa is the optimum moisture content of sample to be detected.

Further, described in step (1), 5 sample moisture content are specially: if clay, moisture content gets 13%, 15%, 17%, 19%, 21%; If sand, moisture content gets 9%, 11%, 13%, 15%, 17%.

Further, described in step (2), 5 sample moisture content are specially: if clay, moisture content gets 12%, 14%, 16%, 18%, 20%; If sand, moisture content gets 8%, 10%, 12%, 14%, 16%.

Further, in step 2, definite method of the penetration resistance value in foundation soil to be detected region is specially: in foundation soil to be detected region, use injection resistance meter to measure 8 test values, in 8 test values, reject a maximum value and a minimum value, get the average of six values of residue as the penetration resistance value in foundation soil to be detected region.

Further, the expression formula of the regression coefficient of regression equation with one unknown described in step 3 a, b is:

$a={\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Yi}\right)}^2/{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Xi}\right)}^2$

$b=\frac{1}{N}{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Yi}\right)}^2-a\×\frac{1}{N}{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Xi}\right)}^2;$

In formula, Xi is sample maximum dry density, and Yi is the penetration resistance value in foundation soil to be detected region, and the span of i is that 18～25, N represents integer.

3. beneficial effect

Adopt technical scheme provided by the invention, compare with existing known technology, there is following remarkable result:

(1) a kind of method of using penetrometer fast detecting foundation soil degree of compaction of the present invention, by gathering maximum dry density and the penetration resistance value information of the different embankments job site in target detection geographic coverage, obtain penetration resistance value-dry density regression equation with one unknown, in very little information gathering, in the situation for the treatment of capacity, obtained the function of the relation between foundation soil penetration resistance value and dry density that characterizes, and the foundation soil dry density error calculating by this relation function is little, accuracy rate is high, use one group of sample of detection method of the present invention can obtain a result in 10～15 minutes, data can be provided rapidly, guide field construction exactly, avoided job site to adopt traditional ground soil compaction detection method to detect frequency large, detection speed is slow, testing result is slow, and then affect the problem of programming,

(2) a kind of method of using penetrometer fast detecting foundation soil degree of compaction of the present invention, principle is simple, precise and high efficiency, can be widely used in industry with civilian construction, highway, railway, bridge, municipal plumbing, petroleum pipeline, water conservancy, build a dam, the engineering construction such as dyke, feed ditch, reservoir and airfield runway.

The specific embodiment

For further understanding content of the present invention, below in conjunction with embodiment, the invention will be further described.

Embodiment 1

A kind of method of using penetrometer fast detecting foundation soil degree of compaction of the present embodiment, its concrete steps are:

Step 1, in target detection geographic coverage, choose at random 25 embankment job sites, target detection area is Shan Nan new district, Huainan City, Anhui Province described in the present embodiment.In embankment job site, choose at random a slice foundation soil to be detected region, at described foundation soil extracted region to be detected sample to be detected, to test room, do compaction test and obtain sample maximum dry density and optimum moisture content.The concrete operation step that the present embodiment obtains maximum dry density and optimum moisture content is:

(1) by quartering, get sample 20kg to be detected, the air-dry 5mm round hole screen that pulverized, mixes the lower soil sample of sieve thoroughly, and by test standard requirement, measures the air-dry moisture content of sample to be detected.According to native plastic limit, estimate optimum moisture content, prepare the sample of 5 different water cuts, the moisture content difference of adjacent 2 samples is 2%.Described in the present embodiment, 5 sample moisture content are specially: if clay, moisture content gets 13%, 15%, 17%, 19%, 21%; If sand, moisture content gets 9%, 11%, 13%, 15%, 17%.These 5 samples light-dutyly hit real sample as one group.The present embodiment is light-duty hits the accuracy that the setting of real sample moisture content can guarantee that optimum moisture content and maximum dry density are measured.

(2) by quartering, get sample 50kg to be detected, the air-dry 20mm sieve that pulverized, mixes the lower soil sample of sieve thoroughly, and by test standard requirement, measures the air-dry moisture content of sample to be detected.According to native plastic limit, estimate optimum moisture content, prepare the sample of 5 different water cuts, the moisture content difference of adjacent 2 samples is 2%.Described in the present embodiment, 5 sample moisture content are specially: if clay, moisture content gets 12%, 14%, 16%, 18%, 20%; If sand, moisture content gets 8%, 10%, 12%, 14%, 16%.These 5 samples hit real sample as one group of heavy type.It is equally also the accuracy in order to guarantee that optimum moisture content and maximum dry density are measured that the present embodiment heavy type hits that real sample moisture content arranges.

(3) the light-duty heavy type of hitting real sample and step (2) acquisition respectively step (1) being obtained is hit real sample and is done compaction test, the concrete steps of each sample being done to compaction test are: compaction cylinder is steadily placed in rigid foundation, compaction cylinder and bottom plate connecting are good, install sleeve, at compaction cylinder inwall, be evenly coated with skim lubrication oil, take a certain amount of sample, pour in compaction cylinder, reality is hit in layering, and every layer of specimen height is equal, and the native face of two-layer intersection should dig hair; Hit after real completing, the specimen height that exceeds compaction cylinder top should be less than 6mm; Unload lower sleeve, with the sample at straight scraper equating compaction cylinder top, remove base plate, sample bottom is exceeded to the equating of compaction cylinder part, clean compaction cylinder outer wall, weigh the gross mass of compaction cylinder and sample, be accurate to 1g, calculate the wet density of sample.Successively each sample is done after compaction test, with bulldozing device, sample is released from compaction cylinder, get at random 2 Specimen Determination moisture content, the difference of 2 moisture content is not more than 1%.

(4) according to following formula, calculate the dry density of sample:

in formula: the dry density that ρ d is sample, get 0.01g/cm ³; The wet density that ρ 0 is sample, gets 0.01g/cm ³; ω i is the moisture content of sample, gets 0.1%;

(5) on rectangular co-ordinate paper, draw the relation curve of dry density and moisture content, ordinate represents sample dry density, abscissa represents sample moisture content, the corresponding ordinate of described relation curve peak point is the maximum dry density of sample to be detected, and corresponding abscissa is the optimum moisture content of sample to be detected.When relation curve can not be drawn peak point, should mend a little, used sample to reuse, should configure separately sample.

Described in step 2, use injection resistance meter Site Detection step 1, the penetration resistance value in foundation soil to be detected region, is accurate to 0.1kg.Definite method of the penetration resistance value in the present embodiment foundation soil to be detected region is specially: roll behind foundation soil to be detected region, in region surface, bore a diameter and be greater than the approximately hole of 8～10cm of 2cm, the degree of depth, open injection resistance meter power supply preheating 5min, carry out instrument zeroing, when handle is mentioned, on instrument screen, should show " 000 ", then two hold handle, press close to two knees as support, pressurizeed in vertical injection soil in alignment probe measured point, when MTD reaches standard depth, read immediately moment peak-peak record.With injection resistance meter, measure 8 test values, in 8 test values, reject a maximum value and a minimum value, get the average of six values of residue as the penetration resistance value in foundation soil to be detected region.The penetration resistance value so obtaining more can represent the penetration resistance in foundation soil to be detected region.

Step 3, the penetration resistance value of utilizing maximum dry density that step 1 obtains and step 2 to obtain, obtain penetration resistance value-dry density regression equation with one unknown, and the formula of this regression equation with one unknown is: Y=aX+b; In formula, Y is dry density * 10, and X is penetration resistance value, and a, b are regression coefficient, is a definite value, and the expression formula of regression coefficient a, b is:

$a={\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Yi}\right)}^2/{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Xi}\right)}^2$

$b=\frac{1}{N}{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Yi}\right)}^2-a\×\frac{1}{N}{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Xi}\right)}^2;$

In formula, Xi is sample maximum dry density, and Yi is the penetration resistance value in foundation soil to be detected region, i=25, and N represents integer.

The regression equation with one unknown of the present embodiment is y=0.0501x+12.45, and this regression equation with one unknown is used while being applicable within the scope of Shan Nan new district, Huainan City, Anhui Province arbitrary embankment job site test foundation soil degree of compaction.25 groups of sample information to be detected that the present embodiment obtains are referring to table 1;

Shan Nan new district, table 1 Huainan City penetration resistance value-dry density data

Foundation soil penetration resistance value is detected in step 4, the arbitrary embankment job site within the scope of Shan Nan new district, Huainan City, Anhui Province described in step 1, the penetration resistance value that detection is obtained is brought the regression equation with one unknown that step 3 obtains into, draws the dry density of this embankment job site foundation soil.Simultaneously in this embankment job site, with core cutter method, cutting parallel sample delivers to test room and carries out dry density test by test standard requirement, the dry density of the foundation soil that the regression equation with one unknown that uses the present embodiment to obtain through check calculates and the error that test room records parallel sample dry density are only 3.12%, the accuracy impact that this error detects foundation soil degree of compaction to the present embodiment is less, can ignore.

Embodiment 2

A kind of method of using penetrometer fast detecting foundation soil degree of compaction of the present embodiment, substantially with embodiment 1, difference is: the target detection area of the present embodiment is for having chosen at random 21 embankment job sites in ， Panji District, Panji District, Huainan City, Anhui Province; The regression equation with one unknown that the present embodiment obtains is y=0.0481x+12.81, and 21 groups of sample information of acquisition are referring to table 2;

Table 2 Huainan City Panji District penetration resistance value-dry density data

The dry density of the foundation soil that the regression equation with one unknown that the present embodiment obtains calculates and the error that test room records parallel sample dry density are only 2.97%, and the accuracy impact that this error detects foundation soil degree of compaction to the present embodiment is less, can ignore.

Embodiment 3

A kind of method of using penetrometer fast detecting foundation soil degree of compaction of the present embodiment, substantially with embodiment 1, difference is: the target detection area of the present embodiment is for having chosen at random 18 embankment job sites in Fengtai district ， Fengtai district, Huainan City, Anhui Province; The regression equation with one unknown that the present embodiment obtains is y=0.0537x+12.2, and 18 groups of sample information of acquisition are referring to table 3;

Fengtai district, table 3 Huainan City penetration resistance value-dry density data

The dry density of the foundation soil that the regression equation with one unknown that the present embodiment obtains calculates and the error that test room records parallel sample dry density are only 3.03%, and the accuracy impact that this error detects foundation soil degree of compaction to the present embodiment is less, can ignore.

A kind of method of using penetrometer fast detecting foundation soil degree of compaction of the present embodiment, by gathering maximum dry density and the penetration resistance value information of the different embankments job site in target detection geographic coverage, obtain penetration resistance value-dry density regression equation with one unknown, in very little information gathering, in the situation for the treatment of capacity, obtained the function of the relation between foundation soil penetration resistance value and dry density that characterizes, and the foundation soil dry density error calculating by this relation function is little, accuracy rate is high, use one group of sample of detection method of the present embodiment can obtain a result in 10～15 minutes, data can be provided rapidly, guide field construction exactly, avoided job site to adopt traditional ground soil compaction detection method to detect frequency large, detection speed is slow, testing result is slow, and then affect the problem of programming.And the principle of the present embodiment is simple, precise and high efficiency, can be widely used in industry with civilian construction, highway, railway, bridge, municipal plumbing, petroleum pipeline, water conservancy, build a dam, the engineering construction such as dyke, feed ditch, reservoir and airfield runway.

Claims (6)

1. a method of using penetrometer fast detecting foundation soil degree of compaction, its concrete steps are:

Step 1, in target detection geographic coverage, choose at random 18～25 embankment job sites, in embankment job site, choose at random a slice foundation soil to be detected region, at described foundation soil extracted region to be detected sample to be detected, to test room, do compaction test and obtain sample maximum dry density and optimum moisture content;

The penetration resistance value in foundation soil to be detected region described in step 2, use injection resistance meter Site Detection step 1;

Step 3, the penetration resistance value of utilizing maximum dry density that step 1 obtains and step 2 to obtain, obtain penetration resistance value-dry density regression equation with one unknown, and the formula of this regression equation with one unknown is: Y=aX+b; In formula, Y is dry density * 10, and X is penetration resistance value, and a, b are regression coefficient, is a definite value;

Foundation soil penetration resistance value is detected in step 4, the embankment job site in target detection geographic coverage described in step 1, and the penetration resistance value that detection is obtained is brought the regression equation with one unknown that step 3 obtains into, draws the dry density of this embankment job site foundation soil.

2. a kind of method of using penetrometer fast detecting foundation soil degree of compaction according to claim 1, is characterized in that: the concrete operation step that step 1 obtains maximum dry density and optimum moisture content is:

(1) by quartering, get sample 20kg to be detected, the air-dry 5mm round hole screen that pulverized, mixes the lower soil sample of sieve thoroughly, and measures the air-dry moisture content of sample to be detected; According to native plastic limit, estimate optimum moisture content, prepare the sample of 5 different water cuts, the moisture content difference of adjacent 2 samples is 2%, and these 5 samples light-dutyly hit real sample as one group;

(2) by quartering, get sample 50kg to be detected, the air-dry 20mm sieve that pulverized, mixes the lower soil sample of sieve thoroughly, and measures the air-dry moisture content of sample to be detected; According to native plastic limit, estimate optimum moisture content, prepare the sample of 5 different water cuts, the moisture content difference of adjacent 2 samples is 2%, and these 5 samples hit real sample as one group of heavy type;

(3) the light-duty heavy type of hitting real sample and step (2) acquisition respectively step (1) being obtained is hit real sample and is done compaction test, calculates the wet density of sample;

(4) according to following formula, calculate the dry density of sample:

in formula: the dry density that ρ d is sample, get 0.01g/cm ³; The wet density that ρ 0 is sample, gets 0.01g/cm ³; ω i is the moisture content of sample, gets 0.1%;

(5) draw the relation curve of dry density and moisture content, ordinate represents sample dry density, abscissa represents sample moisture content, and the corresponding ordinate of described relation curve peak point is the maximum dry density of sample to be detected, and corresponding abscissa is the optimum moisture content of sample to be detected.

3. a kind of method of using penetrometer fast detecting foundation soil degree of compaction according to claim 2, is characterized in that: described in step (1), 5 sample moisture content are specially: if clay, moisture content gets 13%, 15%, 17%, 19%, 21%; If sand, moisture content gets 9%, 11%, 13%, 15%, 17%.

4. a kind of method of using penetrometer fast detecting foundation soil degree of compaction according to claim 3, is characterized in that: described in step (2), 5 sample moisture content are specially: if clay, moisture content gets 12%, 14%, 16%, 18%, 20%; If sand, moisture content gets 8%, 10%, 12%, 14%, 16%.

5. according to a kind of method of using penetrometer fast detecting foundation soil degree of compaction described in claim 2 or 3, it is characterized in that: in step 2, definite method of the penetration resistance value in foundation soil to be detected region is specially: in foundation soil to be detected region, use injection resistance meter to measure 8 test values, in 8 test values, reject a maximum value and a minimum value, get the average of six values of residue as the penetration resistance value in foundation soil to be detected region.

6. according to a kind of method of using penetrometer fast detecting foundation soil degree of compaction described in claim 4 or 5, it is characterized in that: the expression formula of the regression coefficient of regression equation with one unknown described in step 3 a, b is:

$a={\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Yi}\right)}^2/{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Xi}\right)}^2$

$b=\frac{1}{N}{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Yi}\right)}^2-a\×\frac{1}{N}{\left(\underset{i=1}{\overset{N}{\mathrm{\Σ}}}\mathrm{Xi}\right)}^2;$

In formula, Xi is sample maximum dry density, and Yi is the penetration resistance value in foundation soil to be detected region, and the span of i is that 18～25, N represents integer.