CN109632621B - Testing method for simulating weathering process of easily weathered soil - Google Patents

Testing method for simulating weathering process of easily weathered soil Download PDF

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CN109632621B
CN109632621B CN201910103175.8A CN201910103175A CN109632621B CN 109632621 B CN109632621 B CN 109632621B CN 201910103175 A CN201910103175 A CN 201910103175A CN 109632621 B CN109632621 B CN 109632621B
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刘鑫
单浩
洪宝宁
孟可
孙东宁
盛柯
倪铖伟
张立业
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Hohai University HHU
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Abstract

A test method for simulating an efflorescent soil weathering process comprises the following steps: preparing a soil sample with the water content of more than 5% and less than or equal to 40%; filling the soil sample into a container in three layers; placing the container filled with the soil sample into a test furnace, performing microwave action on the soil sample by using a microwave energy generator, and collecting the highest temperature and mass loss rate of the soil sample after the microwave action; the invention relates to a method for simulating the weathering soil samples of different weathering times in a natural state by setting microwave action power and time. The method overcomes the defect that the preparation of the easily weathered soil sample under the natural action takes long time and is not beneficial to research, provides important basis for the change of the physical and mechanical properties of the easily weathered soil according to the weathering process, provides theoretical basis for controlling the physical and mechanical properties of the easily weathered soil to guarantee the engineering quality and the application of related engineering, and has important significance.

Description

Testing method for simulating weathering process of easily weathered soil
Technical Field
The invention belongs to the technical field of highway engineering construction, and particularly relates to a test method for simulating an efflorescent soil weathering process.
Background
The key areas for building highway engineering in China are gradually transferred from coastal plain areas with developed economy to mountain hilly areas with laggard economy, and the soil with poor quality such as easily weathered soil and the like which is often encountered in the process is known by combining site reconnaissance and geological survey data. For example: the easily weathered soil is generally gray black in color, has characteristics of dry cracking, strong water absorption, water swelling and softening, and is easy to rapidly weather after excavation and exposure to cause structural damage and strength reduction and can not be reversed, but the easily weathered soil excavation and exposure to weathering cause strength attenuation law, so that the influence of the strength attenuation of the easily weathered soil after exposure to weathering on engineering safety and stability cannot be deeply analyzed.
Disclosure of Invention
The purpose of the invention is as follows: the problem of influence on engineering safety and stability caused by strength attenuation due to changes of mineral components, particles and structures in a long process that weathered soil is exposed and excavated in corresponding engineering in the prior art and along with the advancement of the weathering degree is solved, and the testing method for simulating the weathered process of the weathered soil is provided.
The technical scheme is as follows: the invention provides a test method for simulating an efflorescence process of easily weathered soil, which comprises the following steps:
1) preparing a sample: preparing a soil sample with the water content of more than 5% and less than or equal to 40%;
2) sample loading: filling the soil sample into a container in three layers;
3) microwave action: putting the container filled with the soil sample into a test furnace, and performing microwave action on the soil sample by using a microwave energy generator, wherein the action power of the microwave energy generator is 0-30 kW, and the action time of the microwave energy generator is 0-2 h;
4) data acquisition: collecting the highest temperature and mass loss rate of the soil sample after the microwave action;
5) obtaining a relational expression of the natural weathering time of the easily weathered soil and the influence factor of the microwave action, wherein the expression is as follows:
f(T,P,t,w,m)=0
in the formula, T is the natural weathering time, P is the microwave action power, T is the microwave action time, w is the water content of the easily weathered soil sample, and m is the quality of the easily weathered soil sample.
Further, in step 1), the natural water content of the soil sample, the natural density of the soil sample, and the sensitivity index are measured.
Further, the relational expression of the easily weathered soil sensitivity index and the easily weathered soil natural weathering time is as follows:
Figure BDA0001966117080000011
wherein y is a sensitivity index, T is weathering time, y0Is a critical value of a sensitive index when the easily weathered soil is completely weathered, y0+A0May reflect the initial value of the model, t0A value range of (90, 115).
Further, the relational expression of the unevenness coefficient, the clay content and the plasticity index and the microwave action influence factor is as follows:
Cu=βk0k1P+βk2t+βk3w+βk4m
η3=βk0k1P+βk2t+βk3w+βk4m
Ip=βk0k1P+βk2t+βk3w+βk4m
in the formula CuIs a non-uniform coefficient, η3Is the content of clay particles, IpThe index is a plasticity index, P is microwave action power, t is microwave action time, omega is the water content of the easily weathered soil sample, m is the quality of the easily weathered soil sample, k is 1,2,3, betak0βk1βk2βk3βk4Undetermined coefficients are obtained for the regression equation.
Further, the expression of the mass loss rate of the soil sample is as follows:
Figure BDA0001966117080000021
Figure BDA0001966117080000022
in the formula, zeta is the mass loss rate, Deltam is the mass loss of the soil body, m is the mass before the test, m 'is the mass after the test, omega is the water content before the test, and omega' is the water content after the test.
Further, in step 5), the expression of the weathering time of the easily weathered soil is:
Figure BDA0001966117080000023
wherein T is the natural weathering time of the easily weathered soil, AT BT CT DT ET FT GT HT JTAre all undetermined coefficients, CuIs a non-uniform coefficient, η3Is the content of clay particles, IpIs a plasticity index.
Further, the material of the container is ceramic or tungsten carbide; the outer surface is a cylindrical surface, the inner surface is a large spherical crown surface, the maximum straight circular surface of the spherical crown surface is parallel to the bottom surface of the container, and the height of the spherical crown is 3/4 of the maximum diameter of the spherical crown surface.
Further, the container includes: the small ball segment, the middle ball table and the upper ball table are all the maximum diameters of spherical crown surfaces of 1/4 in height, and are fixedly arranged between the small ball segment and the middle ball table and between the middle ball table and the upper ball table through two notches.
Further, the sample loading is divided into three layers for sample loading, wherein the sample loading of the first layer is as follows: (1) installing a first protective cylinder on the small segment through a notch, and weighing
Figure BDA0001966117080000024
Filling a soil sample into a small ball gap with a first protective cylinder; (2) loading the small ball segment with the first protective cylinder on a rack, (3) uniformly attaching a vibrating sheet on the circumference of the central cross section of the first protective cylinder, starting a motor to enable the vibrating sheet to continuously vibrate for 3-8 mins, (4) after stopping vibration, putting a steel sheet into the first protective cylinder, starting a jack to compact a soil sample downwards, and pressing the steel sheet to the bottom surface of the small ball segment to stop; (5) lifting the jack, unloading the combined container, removing the first protective cylinder, removing the steel sheet, and finishing the first layer sample loading; second layer sample loading: the middle ball table is arranged on the small ball gap through the notch, the second protective cylinder is arranged through the notch of the middle ball table, and the middle ball table is weighed
Figure BDA0001966117080000031
Loading the soil sample into a middle ball table with a second protective cylinder; loading a middle ball table with a second protective cylinder on the rack, repeating the steps (3) to (5) of the first layer sample loading, and finishing the second layer sample loading; and (3) loading a sample on the third layer: the ball feeding table is arranged on the ball feeding table through the notch, then the first protective cylinder is arranged on the ball feeding table through the notch, and the ball is weighed
Figure BDA0001966117080000032
Loading a soil sample into a ball feeding table with a first protective cylinder; and (5) loading the upper table with the first protective cylinder on the rack, repeating the steps (3) to (5) of the first layer sample loading, and finishing the third layer sample loading.
Further, during the microwave action process in the step 3), the temperature of the soil sample in the center of the container and the temperature of the surface of the soil sample are monitored in real time by using a temperature sensor.
Has the advantages that: the invention can be used for simulating easily weathered soil samples with different weathering times in a natural state indoors by setting microwave action power and time by improving the existing cylindrical soil sample into a spherical-segment soil sample which is easier to uniformly accept microwave action. Establishing regression expressions of the non-uniform coefficient, the clay content and the plasticity index and the microwave action influence factors and relational expressions of the natural weathering and the microwave action influence factors suitable for different conditions. The method overcomes the defect that the preparation of the easily weathered soil sample under the natural action takes long time and is not beneficial to research, provides important basis for the change of the physical and mechanical properties of the easily weathered soil according to the weathering process, provides theoretical basis for controlling the physical and mechanical properties of the easily weathered soil to guarantee the engineering quality and the application of related engineering, and has important theoretical and practical significance.
Drawings
FIG. 1 is a flow chart of a test method of the present invention;
FIG. 2 is a view of a segmental sphere container and a protective cylinder during sample loading according to the present invention, which simulates a weathering process using microwave testing;
FIG. 3 is a schematic illustration of a slot installation for simulating a weathering process using microwave testing in accordance with the present invention.
Detailed Description
The present invention will be further described with reference to the following examples.
Fig. 1 is a flowchart of a testing method for simulating an efflorescent soil weathering process according to the present invention, and as shown in fig. 1, the specific testing steps are as follows:
step 1, sample preparation: taking the un-weathered disturbance to make it into easily weathered soil, and measuring its natural water content w0Natural density ρ0And the like. For the convenience of test use, larger soil blocks of un-weathered soil are crushed by a wood hammer, and the soil with the maximum soil block diameter not more than 2cm is placed in a shade place for natural air drying.
In order to prepare the easily weathered soil with the water content of w, the easily weathered soil (omega is more than or equal to 5% and less than or equal to 40%) is dried for more than 48 hours in an oven at the temperature of 65-70 ℃, and the water content of an air-dried soil sample is measured. And (3) calculating the water adding amount according to the test specification, mixing after adding water, standing, sealing and filling into a glass jar to ensure that the water in the soil sample is uniform.
Step 2, sample loading: filling the soil sample into a container in three layers, as shown in figure 2; the container is made of ceramic or tungsten carbide; the outer surface is a cylindrical surface, the inner surface is a large spherical crown surface, the maximum straight circular surface of the spherical crown surface is parallel to the bottom surface of the container, and the height of the spherical crown is 3/4 of the maximum diameter of the spherical crown surface. The container comprises: the small ball segment, the middle ball table and the upper ball table are all the maximum diameters of spherical crown surfaces of 1/4 in height, and are fixedly arranged between the small ball segment and the middle ball table and between the middle ball table and the upper ball table through two notches, as shown in fig. 3.
The first layer is filled, as shown in figure 2a, a first protective cylinder (r) is arranged on the small ball segment through a notch, wherein the first protective cylinder (r) is a hollow cylinder with the outer diameter of Dcm and the inner diameter of Dcm
Figure BDA0001966117080000041
The height is h cm; weighing soil sample
Figure BDA0001966117080000042
Filling the mixture into a small ball segment with a first protective cylinder I; the small ball with the first protecting cylinder is loaded on the rack and evenly stuck on the circumference of the central cross section of the first protecting cylinder4, starting a motor to enable the vibrating piece to continuously vibrate for 3-8 mins; after stopping shaking, the diameter is
Figure BDA0001966117080000043
Placing a steel sheet with the thickness of 3mm into the first protective cylinder I, starting a jack to compact a soil sample downwards at the speed of 0.013mm/min, and pressing the steel sheet to the bottom surface of the small circular notch to stop; lifting the jack, unloading the combined container, removing the first pile casing and removing the steel sheet; and finishing the first layer sample loading.
A second layer of samples are loaded, as shown in figure 2b, the middle ball table is arranged on the small ball gap through the notch, and then a second protecting cylinder is arranged through the notch of the middle ball table, wherein the second protecting cylinder is a hollow cylinder, the outer diameter of the hollow cylinder is Dcm, the inner diameter of the hollow cylinder is d cm, and the height of the hollow cylinder is h cm; weighing soil sample
Figure BDA0001966117080000044
Putting the ball into a middle ball table with a second protective cylinder II; loading a middle ball table with a second protective cylinder on a rack, uniformly attaching 4 vibrating pieces on the circumference of the central cross section of the second protective cylinder, and starting a motor to enable the vibrating pieces to continuously vibrate for 3-8 mins; after stopping vibration, putting a steel sheet with the diameter of d cm and the thickness of 3mm into a second protective cylinder II, starting a jack to compact a soil sample downwards at the speed of 0.013mm/min, and pressing the steel sheet to the top surface of the middle ball table to stop; lifting the jack, unloading the combined container, removing the second protective cylinder and removing the steel sheet; and finishing the second layer sample loading.
And a third layer of sample loading, as shown in fig. 2c, installing the upper table on the middle table through the notch, installing the first casing (i) on the upper table through the notch, and weighing the soil sample
Figure BDA0001966117080000045
Putting the golf balls into a ball feeding table with a first protective cylinder I; loading a table tennis table with a first protective cylinder I on a rack, uniformly sticking 4 vibrating pieces on the circumference of the central cross section of the first protective cylinder I, and starting a motor to enable the vibrating pieces to continuously vibrate for 3-8 mins; after stopping shaking, the diameter is
Figure BDA0001966117080000046
Placing a steel sheet with the thickness of 3mm into the first protective cylinder I, starting a jack to compact a soil sample downwards at the speed of 0.013mm/min, and pressing the steel sheet to the top surface of the upper table to stop; and lifting the jack, unloading the combined container, removing the first pile casing, removing the steel sheet, and finishing sample loading.
And step 3: microwave action: putting the container filled with the soil sample into a test furnace, and performing microwave action on the soil sample by using a microwave energy generator, wherein the action power of the microwave energy generator is 0-30 kW, and the action time of the microwave energy generator is 0-2 h; in the microwave action process, two temperature sensors are adopted, one temperature sensor is required to be inserted into the center of a sphere, the other temperature sensor is required to be directly led into a computer to form a temperature-time change diagram and record the highest temperature T of the center of the sample in the whole test processcMaximum temperature T of sample surfaces(ii) a The monitoring system shoots the surface condition of the soil sample in real time for infrared scanning photography and displays the surface condition in a monitoring room host computer in an equal-ratio amplification manner, the computer can automatically capture the surface cracks of the soil sample, calculate the width of the cracks according to the amplification ratio to form a 'crack width-time change diagram', record the maximum crack width C of the whole test process and mark the cracks in the shot picture. The temperature sensor and the monitoring system are used for monitoring the temperature of the soil sample and the development condition of the crack in real time, the condition of the soil sample in the test process is mastered,
and 4, step 4: and (6) data acquisition. Automatically stopping the microwave energy generator after a set time, opening a cabin door of the test oven, taking out a sample with a heat insulation glove, opening a pot cover, measuring the temperature of the soil sample on the inner surface and different positions of the inner part of the pot by using a handheld infrared thermometer and a shovel, and taking the maximum temperature Ttem(at T)c TsAnd hand-held infrared thermometer readings) and recorded. And in order to control the consistency of the variables of the soil mass measurement before and after the test, pouring out the soil sample after naturally cooling to room temperature, weighing, removing the water mass difference before and after the test for the soil mass loss, and calculating the soil mass loss rate.
The sensitive index of the easily weathered soil and the natural weathering time of the easily weathered soil are fitted by adopting an exponential relationship:
Figure BDA0001966117080000051
wherein y is a sensitivity index, T is weathering time, y0Is a critical value of a sensitive index when the easily weathered soil is completely weathered, y0+A0May reflect the initial value of the model, t0A value range of (90, 115).
Simulating influence factors, establishing nonuniform coefficient, clay content and plasticity index and microwave action
The regression expressions of the influencing factors are as follows in sequence:
Cu=βk0k1P+βk2t+βk3w+βk4m
η3=βk0k1P+βk2t+βk3w+βk4m
Ip=βk0k1P+βk2t+βk3w+βk4m
wherein C isuIs a non-uniform coefficient, η3Is a clay content and IpIs a plasticity index; p is microwave action power, t is microwave action time, omega is water content of the easily weathered soil sample, m is quality of the easily weathered soil sample, k is 1,2,3, betak0βk1βk2βk3βk4Undetermined coefficients are obtained for the regression equation.
According to a functional relation of the natural weathering time and the microwave action influence factors:
f(T,P,t,w,m)=0
wherein T is the natural weathering time, P is the microwave action power, T is the microwave action time, w is the water content of the easily weathered soil sample, and m is the quality of the easily weathered soil sample.
And (3) reliability verification: and (3) carrying out XRD identification, particle analysis tests and limit water content tests on the soil sample subjected to simulated weathering in the microwave test, comparing the obtained data with the data of the soil sample exposed to natural weathering, and confirming the reliability of the simulation test.
In the excavation process of the easily weathered soil slope, a heavy hammer low-impact method is adopted to quickly impact the thin-wall soil sampler into soil at a position which is 5-7 m deep below the surface of an original mountain body, and an original un-weathered easily weathered soil sample is transported back to a laboratory.
The density rho of the configured soil sample is 1.80g/cm3The microwave action power P is 3kW, 4kW, 5kW and 6kW, the microwave action time t is 20min, 30min, 40min and 50min, the water content w of the soil sample is 15%, 20%, 25% and 30%, and the mass m of the soil sample is 2kg, 3kg, 4kg and 5 kg. And (3) simulating the weathering test working condition of the easily weathered soil according to the microwave designed by the matrix statistical test.
From the temperature change condition, the temperature after the microwave action can reach 457.2 ℃ at most and is only 103.6 ℃ at least, and the temperature is basically consistent with the change of sensitive indexes, which indirectly shows that the catalysis of the microwave on the easily weathered soil is realized by heating.
From the quality loss situation, the maximum quality loss rate reaches 2.46 percent, the minimum quality loss rate is 0.50 percent, and the quality loss rate is smaller.
The relation between the easily weathered soil sensitivity index and the natural weathering time is fitted in an exponential mode:
non-uniformity coefficient:
Figure BDA0001966117080000061
clay content:
Figure BDA0001966117080000062
plasticity index:
Figure BDA0001966117080000063
assuming that the established regression equation satisfies the multiple primary regression model, let the non-uniformity coefficient, the cosmid content and the plasticity index be y1、y2And y3The microwave action power, time, soil sample water content and soil sample mass are respectivelyx1,x2,x3,x4. The results of each set of orthogonal tests are presented
Figure BDA0001966117080000064
In the formula: k is 1,2, 3; beta is aksAnd S is the undetermined coefficient of the regression equation, S is the serial number of the undetermined coefficient, and S is totally S undetermined coefficients, wherein S is 5, S is 0,1,2,3 and 4 in the test. y iskiAnd i is an orthogonal test serial number, and N groups of tests are total, wherein N is 16, i is 1 and 16. x is the number of1i,x2i,x3iAnd x4iTaking the value of the influencing factor of the i test, epsilonkiFor each set of experimental errors.
Let ykiAnd betaksLeast squares estimates are respectively
Figure BDA0001966117080000065
And
Figure BDA0001966117080000067
the expression of the first regression equation of the sensitive index and the influencing factor is as follows:
Figure BDA0001966117080000068
the sum of squares of errors of regression equations of all sensitive indexes is set as QkThen, then
Figure BDA0001966117080000071
When Q iskAt the minimum, the predictive regression equation is the best match of the original equation. And the requirement for the least sum of squared errors is:
Figure BDA0001966117080000072
after finishing and calculating to obtain
Figure BDA0001966117080000073
Figure BDA0001966117080000074
Figure BDA0001966117080000075
Then the regression expressions of the non-uniformity coefficient, the clay content and the plasticity index and the microwave effect influence factors are sequentially as follows:
Cu=38.389-2.432P-0.304t+0.134w+0.637m
η3=21.415+2.033P+0.211t-0.178w-0.420m
Ip=5.011+1.828P+0.174t-0.101w-0.348m
and evaluating the regression equation by adopting R test, F test and t test. And finally, establishing a relational expression of the natural weathering time and the simulation influence factors by combining the relation between the sensitive indexes and the natural weathering time:
f(T,P,t,w,m)=0
the relation between simultaneous sensitivity indexes and natural weathering time and the influence factors of microwave action are obtained as follows:
Figure BDA0001966117080000076
the relational expressions of the influence factors of the natural weathering and the microwave action under different conditions can be respectively established according to different test requirements.
Knowing the state and the target of the soil sample, solving the microwave power and time:
Figure BDA0001966117080000081
the known microwave equipment and target calculate the water content and the mass of the soil sample:
Figure BDA0001966117080000082
knowing the influencing factors, the weathering time is calculated as:
Figure BDA0001966117080000083
from the results of X-ray diffraction spectrum analysis, it was found that the weatherable soil mainly contained quartz (SiO2), mica (KAl2[ AlSi3O10] [ OH ]2), illite (KAl2[ (Al, Si) Si3O10] (OH) 2. nH2O), and a small amount of kaolinite, chlorite, montmorillonite and the like. This is consistent with the results of natural exposure weathering efflorescence soil analysis. The easily weathered soil after the microwave action comprises the following mineral components: the content of quartz is 30.24%, the content of mineral components such as mica, calcite and potash feldspar is 16.50%, and the content of clay minerals (including kaolinite, illite, montmorillonite and chlorite) is 36.11%. Compared with the mineral component content of the undeweathered easily weathered soil, the content of diagenetic minerals is obviously reduced from 39.81 percent of the initial state, the content of clay minerals is obviously increased from 20.04 percent of the initial state, and the change rule of the mineral component of the easily weathered soil is basically consistent with that of the easily weathered soil under the action of natural weathering.
XRD analysis results show that the transformation from diagenetic minerals in the easily weathered soil to clay minerals can be realized under the action of microwaves, namely, a test method for simulating the natural weathering of the easily weathered soil under the action of the microwaves has certain feasibility.
The real value of the easily weathered soil after natural weathering, the calculated value calculated according to the relational expression and the test value after microwave action. The calculation results and the test results show that:
under different weathering times, compared with the actual value of the uneven coefficient of the easily weathered soil under the action of natural weathering, the calculated value has the maximum difference of 1.6 and the minimum difference of 0 from the actual value. The maximum difference between the test value and the true value is 1.2, and the error is 5.48 percent when the natural weathering is carried out for 40 days; the minimum difference was 0.5, which occurred at a natural weathering time of 80d with an error of 2.53%.
Under different weathering times, the maximum difference value between the true value and the calculated value of the content of the clay grains of the easily weathered soil is 0.9 percent, the error is 2.49 percent, the minimum difference value is 0.5 percent, and the error is only 1.46 percent; the maximum difference between the test value and the true value is 1.6%, the error is 5.05%, the minimum difference is 0.2%, and the error is only 0.55%.
Under different weathering times, the maximum difference value between the true value and the calculated value of the plasticity index of the easily weathered soil is 0.2, the minimum difference value is 0.1, and the errors are less than 1%; the maximum difference between the test value and the true value is 0.9, the error is 4.41%, the minimum difference is 0.5, and the error is 4.00%. The maximum difference between the test value and the actual value is basically consistent with the maximum error and the minimum error of the actual value, which shows that the simulation test and the relation formula provided by the text have certain accurate determination.

Claims (8)

1. A test method for simulating an efflorescent soil weathering process is characterized by comprising the following steps:
1) preparing a sample: preparing a soil sample with the water content of more than 5% and less than or equal to 40%;
2) sample loading: filling the soil sample into a container in three layers;
3) microwave action: putting the container filled with the soil sample into a test furnace, and performing microwave action on the soil sample by using a microwave energy generator, wherein the action power of the microwave energy generator is 0-30 kW, and the action time of the microwave energy generator is 0-2 h;
4) data acquisition: collecting the highest temperature and mass loss rate of the soil sample after the microwave action;
5) the expression of the natural weathering time of the easily weathered soil is obtained as follows:
Figure FDA0002949649910000011
wherein T is the natural weathering time of the easily weathered soil, AT BT CT DT ET FT GT HT JTAre all undetermined coefficients, CuIs a non-uniform coefficient, η3Is the content of clay particles, IpIs a plasticity index; the relational expression of the nonuniform coefficient, the clay content and the plasticity index and the microwave action influence factor is as follows:
Cu=βk0k1P+βk2t+βk3w+βk4m
η3=βk0k1P+βk2t+βk3w+βk4m
Ip=βk0k1P+βk2t+βk3w+βk4m
wherein P is microwave action power, t is microwave action time, omega is water content of the easily weathered soil sample, m is quality of the easily weathered soil sample, k is 1,2,3, betak0βk1βk2βk3βk4Undetermined coefficients are obtained for the regression equation.
2. The test method for simulating an efflorescent soil weathering process of claim 1, wherein: in the step 1), the natural water content of the soil sample, the natural density of the soil sample and sensitive indexes are measured, wherein the sensitive indexes comprise a non-uniform coefficient, a clay content and a plasticity index.
3. The test method for simulating an efflorescent soil weathering process of claim 2, wherein: the relational expression of the easily weathered soil sensitivity index and the easily weathered soil natural weathering time is as follows:
Figure FDA0002949649910000012
wherein y is a sensitivity index, T is weathering time, y0Is a critical value of a sensitive index when the easily weathered soil is completely weathered, y0+A0May reflect the initial value of the model, t0A value range of (90, 115).
4. The test method for simulating an efflorescent soil weathering process of claim 1, wherein: the expression of the mass loss rate of the soil sample is as follows:
Figure FDA0002949649910000021
Figure FDA0002949649910000022
in the formula, zeta is the mass loss rate, Deltam is the mass loss of the soil body, m is the mass before the test, m 'is the mass after the test, omega is the water content before the test, and omega' is the water content after the test.
5. The test method for simulating an efflorescent soil weathering process of claim 1, wherein: the container is made of ceramic or tungsten carbide; the outer surface is a cylindrical surface, the inner surface is a large spherical crown surface, the maximum straight circular surface of the spherical crown surface is parallel to the bottom surface of the container, and the height of the spherical crown is 3/4 of the maximum diameter of the spherical crown surface.
6. The test method for simulating an efflorescent soil weathering process of claim 5, wherein: the container comprises: the small ball segment, the middle ball table and the upper ball table are all the maximum diameters of spherical crown surfaces of 1/4 in height, and are fixedly arranged between the small ball segment and the middle ball table and between the middle ball table and the upper ball table through two notches.
7. The test method for simulating an efflorescent soil weathering process of claim 1, wherein: the sample loading is divided into three layers for sample loading, wherein the first layer of sample loading is as follows: (1) installing a first protective cylinder on the small segment through a notch, and weighing
Figure FDA0002949649910000023
Filling a soil sample into a small ball gap with a first protective cylinder; (2) loading the small ball segment with the first protective cylinder on a rack, (3) uniformly attaching vibration plates on the circumference of the central cross section of the first protective cylinder, starting a motor to enable the vibration plates to vibrate for 3-8 mins continuously, (4) after stopping vibration, putting a steel sheet into the first protective cylinder, starting a jack to compact a soil sample downwards, and pressing the steel sheet to the bottom surface of the small ball segment to stop; (5) lifting the jack, unloading the combined container, removing the first protective cylinder, removing the steel sheet, and finishing the first layer sample loading; second layer sample loading: the middle ball table is arranged on the small ball gap through the notch, the second protective cylinder is arranged through the notch of the middle ball table, and the middle ball table is weighed
Figure FDA0002949649910000024
Loading the soil sample into a middle ball table with a second protective cylinder; loading a middle ball table with a second protective cylinder on the rack, repeating the steps (3) to (5) of the first layer sample loading, and finishing the second layer sample loading; and (3) loading a sample on the third layer: the ball feeding table is arranged on the ball feeding table through the notch, then the first protective cylinder is arranged on the ball feeding table through the notch, and the ball is weighed
Figure FDA0002949649910000025
Loading a soil sample into a ball feeding table with a first protective cylinder; and (5) loading the upper table with the first protective cylinder on the rack, repeating the steps (3) to (5) of the first layer sample loading, and finishing the third layer sample loading.
8. The test method for simulating an efflorescent soil weathering process of claim 1, wherein: and in the microwave action process of the step 3), monitoring the temperature of the soil sample in the center of the container and the temperature of the surface of the soil sample in real time by using a temperature sensor.
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