A long-term determination method for roadbed equilibrium humidity

Abstract

The present invention discloses a long-term determination method for equilibrium moisture of roadbed, which belongs to the technical field of road engineering. The present invention aims to solve the technical problem that the existing estimation of roadbed moisture is inaccurate. The technical solution adopted is as follows: the method comprises burying a closed moisture sensor device and an open moisture sensor device on the top of the roadbed of layered compacted roadbeds with a compaction degree of 93%, a compaction degree of 94%, and a compaction degree of 96%, respectively, measuring the moisture of the roadbed soil once a quarter each year, and continuously collecting the data for several years. By comparing the moisture data collected by the closed moisture sensor device and the open moisture sensor device in the roadbed corresponding to the compaction degree, the optimal moisture content data of the roadbed soil during construction and the moisture content change of the roadbed moisture with environmental changes are obtained, thereby determining the difference in the roadbed moisture change and the equilibrium moisture of the roadbed; wherein, the interior of the closed moisture sensor device is filled with the construction roadbed soil of the corresponding layer of compacted roadbed and the moisture is kept from being lost.

Description

Technical Field

[0001] The invention relates to the technical field of road engineering, in particular to a long-term determination method of roadbed equilibrium humidity. Background Art

[0002] High-quality and durable roadbed and pavement structure are the key to high-quality and long-life highways, and whether the roadbed can provide strong bearing capacity is the core to ensure the durability and greenness of the roadbed and pavement. The excellent bearing capacity of the roadbed is directly affected by the moisture content of the roadbed soil. Therefore, when designing the roadbed and pavement structure, the moisture content of the roadbed, especially the equilibrium moisture content of the roadbed under the long-term effects of load and environment, is an issue that needs to be focused on. In the prior art, when performing pavement structure design verification, the rebound modulus of the roadbed top adopts the rebound modulus of the roadbed under the equilibrium moisture state. At the same time, the prior art also stipulates that the rebound modulus requirement of the roadbed top is the rebound modulus under the equilibrium moisture state of the roadbed.

[0003] However, determining the equilibrium moisture content of the subgrade is currently limited by the complexity of long-term monitoring. Furthermore, after subgrade construction, the subgrade beneath the pavement structure becomes closed, making it difficult to continuously obtain subgrade soil moisture data over time. Currently, the most commonly used method for determining subgrade equilibrium moisture content typically relies on estimating it using a subgrade moisture model. However, these estimates are often inaccurate, leading to inaccurate calculated subgrade modulus of resilience, which seriously impacts the rationality and reliability of highway subgrade and pavement structure design.

[0004] Therefore, how to measure the long-term humidity changes of the roadbed and then obtain the equilibrium humidity of the roadbed is a technical problem that needs to be solved urgently. Summary of the Invention

[0005] The technical task of the present invention is to provide a long-term determination method of roadbed equilibrium humidity to solve the problem of inaccurate estimation of roadbed humidity.

[0006] The technical task of the present invention is achieved in the following manner: a long-term method for measuring equilibrium moisture content of a roadbed, comprising burying a closed moisture sensor device and an open moisture sensor device on the top of the subgrade of a layered compacted roadbed with a compaction degree of 93%, a compaction degree of 94%, and a compaction degree of 96%, respectively. The subgrade soil moisture is measured once a quarter each year, and the data are collected continuously for several years. By comparing the moisture data collected by the closed moisture sensor device and the open moisture sensor device in the subgrade corresponding to the compaction degree, the optimal moisture content of the subgrade soil during construction and the moisture content change of the subgrade soil with environmental changes are obtained, thereby determining the difference in subgrade moisture change and the subgrade equilibrium moisture content.

[0007] Among them, the closed humidity sensor device is filled with the construction roadbed soil of the corresponding layer of compacted roadbed to keep moisture from being lost; the open humidity sensor device is filled with construction roadbed soil and is connected with the roadbed soil of the corresponding roadbed layer to maintain moisture exchange.

[0008] Preferably, the construction roadbed soil filled in the closed moisture sensor device installed on the compacted roadbed with a compaction degree of 93% and the open moisture sensor device is coarse-grained soil.

[0009] Preferably, the construction roadbed soil filled in the closed moisture sensor device and the open moisture sensor device installed on the compacted roadbed with a compaction degree of 94% is coarse-grained soil and fine-grained soil.

[0010] Preferably, the construction roadbed soil filled in the closed moisture sensor device installed on the compacted roadbed with a compaction degree of 93% and the open moisture sensor device is cement-improved soil, lime-fly ash-stabilized soil, or lime-improved soil.

[0011] More preferably, the enclosed sensor device includes a PVC cylindrical tube and a humidity sensor. The humidity sensor is installed in the PVC cylindrical tube. Plastic covers are installed at both ends of the PVC cylindrical tube. A lead hole is opened in the center of the plastic cover. The data cable of the humidity sensor is led out of the PVC cylindrical tube through the lead hole.

[0012] The production process of the closed sensor device is as follows:

[0013] (1) Fill the PVC cylindrical tube with the subgrade soil of the corresponding layer of compacted subgrade during construction. The filling amount of the subgrade soil of the corresponding layer of compacted subgrade is set according to the compaction degree of the subgrade.

[0014] (2) When filling the roadbed soil of the corresponding layer of compacted roadbed, place the humidity sensor 1 and manually compact it;

[0015] (3) After placing the corresponding layer of compacted roadbed soil and humidity sensor 1, cover the two ends of the PVC cylindrical tube 1 with plastic caps 1, and lead the data line of the humidity sensor 1 through the lead hole 1;

[0016] (4) wax-seal the PVC cylindrical tube as a whole;

[0017] (5) The encapsulated closed humidity sensor device is placed on the top of the roadbed with a compaction degree of 93%, a compaction degree of 94% and a compaction degree of 96% after the roadbed is mixed and before the roadbed is rolled, and then the roadbed is rolled.

[0018] More preferably, the open humidity sensor device includes a second PVC cylindrical tube and a second humidity sensor. The second humidity sensor is installed in the second PVC cylindrical tube. Two plastic covers are installed at both ends of the second PVC cylindrical tube. A second lead hole is opened in the center of the second plastic cover. The data line of the second humidity sensor is led out of the second PVC cylindrical tube through the second lead hole. A plurality of evenly distributed communication holes are opened on the side wall of the second PVC cylindrical tube.

[0019] The details of the fabrication process for the open humidity sensor device are as follows:

[0020] (1) Fill the PVC cylindrical tube 2 with the subgrade soil of the corresponding layer of compacted subgrade during construction. The filling amount of the subgrade soil of the corresponding layer of compacted subgrade is set according to the compaction degree of the subgrade.

[0021] (2) When filling the roadbed soil of the corresponding layer with compacted roadbed, place the second humidity sensor and perform manual compaction;

[0022] (3) After placing the corresponding layer of compacted roadbed soil and humidity sensor 2, cover the two ends of the PVC cylindrical tube 2 with plastic covers 2, and lead the data line of humidity sensor 2 through the lead hole 2;

[0023] (4) The side wall of the PVC cylindrical tube 2 is opened with a plurality of evenly distributed connecting holes. The diameter of the connecting holes is 5 mm, and the spacing between two adjacent connecting holes is 20 mm.

[0024] (5) The open moisture sensor device was placed on the top of the roadbed with a compaction degree of 93%, a compaction degree of 94% and a compaction degree of 96% after the roadbed was mixed and before the roadbed was rolled. Then the roadbed was rolled.

[0025] More preferably, the mass of the roadbed soil filled in the PVC cylindrical tube 1 and the PVC cylindrical tube 2 is calculated based on the compaction degree, the maximum dry density of the roadbed soil, and the volume of the PVC cylindrical tube 1 or the PVC cylindrical tube 2, using the following formula:

[0026] m s =Q×ρ max ×π×r 2 ×h;

[0027] Among them, m s Indicates the mass of soil to be filled, in g; Q indicates the degree of compaction; ρ max Indicates the maximum dry density of roadbed soil in g / cm 3 ; π is a constant with a value of 3.14; r represents the radius of the bottom surface of the PVC cylindrical tube 1 or the PVC cylindrical tube 2, in cm; h represents the radius of the PVC cylindrical tube 1 or the PVC cylindrical tube 2, in cm.

[0028] More preferably, before the humidity sensor 1 and the humidity sensor 2 are installed into the corresponding PVC cylindrical tube 1 and the PVC cylindrical tube 2, the volume moisture content collected by the humidity sensor 1 and the humidity sensor 2 need to be calibrated with the moisture content of the roadbed soil, and a calibration curve between the volume moisture content and the moisture content of the roadbed soil needs to be established.

[0029] More preferably, the volumetric moisture content of the compacted roadbed with a compaction degree of 93% and the moisture content of the roadbed soil satisfy the following formula:

[0030] y1=a1x1-b1;

[0031] Among them, y1 represents the volume moisture content of the roadbed with a compaction degree of 93%; x1 represents the moisture content of the roadbed soil with a compaction degree of 93%; a1 represents the correlation coefficient, which ranges from 1.47 to 1.87; b1 is a constant, which ranges from 0.0073 to 0.0103.

[0032] More preferably, the volumetric moisture content of the compacted roadbed with a compaction degree of 94% and the moisture content of the roadbed soil satisfy the following formula:

[0033] y2=a2x2+b2;

[0034] Where y2 represents the volumetric moisture content of the roadbed at a compaction degree of 94%; x2 represents the moisture content of the roadbed soil at a compaction degree of 94%; a2 represents the correlation coefficient, with a value ranging from 0.992 to 1.392; b2 is a constant, with a value range of 0.0316 to 0.0716;

[0035] The volume moisture content of the compacted roadbed with a compaction degree of 96% and the moisture content of the roadbed soil satisfy the following formula:

[0036] y3=a3x3+b3;

[0037] Among them, y3 represents the volume moisture content of the roadbed at a compaction degree of 96%; x3 represents the moisture content of the roadbed soil at a compaction degree of 96%; a3 represents the correlation coefficient, which ranges from 2.04 to 2.44; b3 is a constant, which ranges from 0.1224 to 0.1624.

[0038] The long-term determination method of roadbed equilibrium humidity of the present invention has the following advantages:

[0039] (1) The present invention realizes continuous testing of the optimal moisture content of the roadbed soil in different compaction areas during construction, the change in moisture content of the roadbed during operation, and the equilibrium moisture content after the roadbed stabilizes under environmental influences. This effectively measures the equilibrium moisture content of the roadbed and solves the problem of inaccurate estimation of roadbed moisture in existing systems.

[0040] (2) The present invention fills different roadbed soils into the closed and open humidity sensors of the corresponding roadbed according to different compaction degrees, ensuring that the pores for water exchange in the roadbed soils at different compaction degrees are different, and the water exchange capacity is also different, thereby improving the accuracy of the corresponding roadbed humidity measurement;

[0041] (3) The present invention can measure the long-term humidity change of the roadbed, obtain the actual law of the roadbed humidity change, and then obtain the equilibrium humidity of the roadbed by measuring the roadbed humidity after long-term stability;

[0042] (4) The present invention realizes the long-term testing and determination of the equilibrium humidity of the roadbed, providing strong support for the roadbed and pavement design and mechanical calculation analysis in road structure design; at the same time, it ensures more accurate acquisition of the equilibrium humidity of the roadbed, effectively controls the range of the rebound modulus of the roadbed top surface, and provides a guarantee for the design and optimization of the material and thickness of the pavement structure layer.

[0043] Therefore, the present invention has the characteristics of reasonable design, simple structure, easy processing, convenient use, and multiple uses, and thus has good promotion and use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The present invention will be further described below with reference to the accompanying drawings.

[0045] Attachment Figure 1 Schematic diagram of the installation position of the moisture sensor on the top of the compacted roadbed with different compaction degrees;

[0046] Attachment Figure 2 is a schematic diagram of a closed humidity sensor device;

[0047] Attachment Figure 3 is a schematic diagram of an open humidity sensor device;

[0048] Attachment Figure 4 The calibration curve of the subgrade soil with the best moisture content of 93% compaction degree;

[0049] Attachment Figure 5 The calibration curve of the subgrade soil with the best moisture content of 94% compaction degree;

[0050] Attachment Figure 6 The calibration curve of the subgrade soil with the best moisture content of 96% compaction degree;

[0051] Attachment Figure 7 Schematic diagram of long-term testing of roadbed humidity.

[0052] In the figure: 1. PVC cylindrical tube 1, 2. Humidity sensor 1, 3. Plastic cover 1, 4. Lead hole 1, 5. Data cable, 6. PVC cylindrical tube 2, 7. Humidity sensor 2, 8. Plastic cover 2, 9. Lead hole 2, 10. Connecting hole. DETAILED DESCRIPTION

[0053] The following is a detailed description of a method for long-term determination of equilibrium moisture content of a roadbed according to the present invention with reference to the accompanying drawings and specific embodiments.

[0054] In the description of the present invention, it should be understood that terms such as "upper," "lower," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" are used to indicate positions or relationships based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate description and simplify the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and are therefore not to be construed as limitations of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

[0055] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0056] Example 1:

[0057] As attached Figure 1 As shown, this embodiment provides a long-term method for measuring equilibrium moisture content of a roadbed. This method involves embedding a closed moisture sensor device and an open moisture sensor device on the top of the subgrade layers of a layered compacted roadbed with a compaction degree of 93%, a compaction degree of 94%, and a compaction degree of 96%, respectively. The subgrade soil moisture content is measured once a quarter each year, and the data is collected continuously for several years. By comparing the moisture data collected by the closed moisture sensor device and the open moisture sensor device in the subgrade layers corresponding to the compaction degree, the optimal moisture content of the subgrade soil during construction and the moisture content change of the subgrade soil as the environment changes are obtained, thereby determining the difference in subgrade moisture change and the subgrade equilibrium moisture content.

[0058] Among them, the closed humidity sensor device is filled with the construction roadbed soil of the corresponding layer of compacted roadbed to keep moisture from being lost; the open humidity sensor device is filled with construction roadbed soil and is connected with the roadbed soil of the corresponding roadbed layer to maintain moisture exchange.

[0059] In this embodiment, the construction roadbed soil filled in the closed moisture sensor device and the open moisture sensor device installed on the compacted roadbed with a compaction degree of 93% is coarse-grained soil.

[0060] In this embodiment, the construction roadbed soil filled in the closed moisture sensor device and the open moisture sensor device installed on the compacted roadbed with a compaction degree of 94% is coarse-grained soil and fine-grained soil.

[0061] In this embodiment, the construction roadbed soil filled in the closed moisture sensor device installed on the compacted roadbed with a compaction degree of 93% and the open moisture sensor device is cement-improved soil or lime-fly ash-stabilized soil or lime-improved soil.

[0062] As attached Figure 2 As shown, the enclosed sensor device in this embodiment includes a PVC cylindrical tube 1 and a humidity sensor 2. Humidity sensor 2 is installed within the PVC cylindrical tube 1. Plastic caps 3 are mounted on both ends of the PVC cylindrical tube 1. A lead hole 4 is provided in the center of the plastic cap 3. A data cable 5 of humidity sensor 2 is led out of the PVC cylindrical tube 1 through the lead hole 4. The bottom diameter of the PVC cylindrical tube 1 is 10 cm, and the height is 10 cm.

[0063] The manufacturing process of the enclosed sensor device in this embodiment is as follows:

[0064] (1) Fill the PVC cylindrical tube 1 with the subgrade soil of the corresponding layer of compacted subgrade during construction. The filling amount of the subgrade soil of the corresponding layer of compacted subgrade is set according to the compaction degree of the subgrade.

[0065] (2) When filling the corresponding layer of compacted roadbed soil, place the humidity sensor 2 and manually compact it;

[0066] (3) After placing the corresponding layer of compacted roadbed soil and humidity sensor 2, cover the two ends of the PVC cylindrical tube 1 with plastic covers 3, and lead the data line 5 of the humidity sensor 1 through the lead hole 4;

[0067] (4) Wax seal the PVC cylindrical tube 1 as a whole;

[0068] (5) The encapsulated closed humidity sensor device is placed on the top of the roadbed with a compaction degree of 93%, a compaction degree of 94% and a compaction degree of 96% after the roadbed is mixed and before the roadbed is rolled, and then the roadbed is rolled.

[0069] As attached Figure 3As shown, the open humidity sensor device in this embodiment includes a PVC cylindrical tube 6 and a humidity sensor 7. The humidity sensor 7 is installed in the PVC cylindrical tube 6. Plastic covers 8 are installed at both ends of the PVC cylindrical tube 6. A lead hole 9 is provided in the center of the plastic cover 8. The data cable 5 of the humidity sensor 7 is led out of the PVC cylindrical tube 6 through the lead hole 9. The side wall of the PVC cylindrical tube 6 is provided with a plurality of evenly distributed communication holes 10. The bottom diameter of the PVC cylindrical tube 6 is 10 cm, and the height is 10 cm.

[0070] The manufacturing process of the open humidity sensor device in this embodiment is as follows:

[0071] (1) Fill the PVC cylindrical tube 26 with the subgrade soil of the corresponding layer of compacted subgrade during construction. The filling amount of the subgrade soil of the corresponding layer of compacted subgrade is set according to the compaction degree of the subgrade.

[0072] (2) When filling the corresponding layer of compacted roadbed soil, place the humidity sensor 27 and manually compact it;

[0073] (3) After placing the corresponding layer of compacted roadbed soil and humidity sensor 27, cover the two ends of the PVC cylindrical tube 26 with plastic covers 28 respectively, and lead the data line 5 of the humidity sensor 26 through the lead hole 29;

[0074] (4) The side wall of the PVC cylindrical tube 2 6 is opened with a plurality of evenly distributed connecting holes 10. The diameter of the connecting holes 10 is 5 mm, and the distance between two adjacent connecting holes 10 is 20 mm.

[0075] (5) The open moisture sensor device was placed on the top of the roadbed with a compaction degree of 93%, a compaction degree of 94% and a compaction degree of 96% after the roadbed was mixed and before the roadbed was rolled. Then the roadbed was rolled.

[0076] The mass of the roadbed soil filled into the PVC cylindrical tube 1 and the PVC cylindrical tube 2 in this embodiment is calculated based on the degree of compaction, the maximum dry density of the roadbed soil, and the volume of the PVC cylindrical tube 1 or the PVC cylindrical tube 2 using the following formula:

[0077] m s =Q×ρ max ×π×r 2 ×h;

[0078] Among them, m s Indicates the mass of soil to be filled, in g; Q indicates the degree of compaction; ρ max Indicates the maximum dry density of roadbed soil in g / cm 3; π is a constant with a value of 3.14; r represents the radius of the bottom surface of the PVC cylindrical tube 1 or the PVC cylindrical tube 2 6, in cm; h represents the radius of the PVC cylindrical tube 1 or the PVC cylindrical tube 2 6, in cm.

[0079] Before the humidity sensor 1 2 and the humidity sensor 2 7 in this embodiment are installed into the corresponding PVC cylindrical tube 1 and the PVC cylindrical tube 2 6, it is necessary to calibrate the volume moisture content collected by the humidity sensor 1 2 and the humidity sensor 2 7 with the moisture content of the roadbed soil, and establish a calibration curve between the volume moisture content and the moisture content of the roadbed soil.

[0080] As attached Figure 4 As shown, in this embodiment, the volume moisture content of the compacted roadbed with a compaction degree of 93% and the moisture content of the roadbed soil satisfy the following formula:

[0081] y1=a1x1-b1;

[0082] Among them, y1 represents the volume moisture content of the roadbed with a compaction degree of 93%; x1 represents the moisture content of the roadbed soil with a compaction degree of 93%; a1 represents the correlation coefficient, which ranges from 1.47 to 1.87; b1 is a constant, which ranges from 0.0073 to 0.0103.

[0083] As attached Figure 5 As shown, in this embodiment, the volume moisture content of the compacted roadbed with a compaction degree of 94% and the moisture content of the roadbed soil satisfy the following formula:

[0084] y2=a2x2+b2;

[0085] Where y2 represents the volumetric moisture content of the roadbed at a compaction degree of 94%; x2 represents the moisture content of the roadbed soil at a compaction degree of 94%; a2 represents the correlation coefficient, with a value ranging from 0.992 to 1.392; b2 is a constant, with a value range of 0.0316 to 0.0716;

[0086] As attached Figure 6 As shown, in this embodiment, the volume moisture content of the compacted roadbed with a compaction degree of 96% and the moisture content of the roadbed soil satisfy the following formula:

[0087] y3=a3x3+b3;

[0088] Among them, y3 represents the volume moisture content of the roadbed at a compaction degree of 96%; x3 represents the moisture content of the roadbed soil at a compaction degree of 96%; a3 represents the correlation coefficient, which ranges from 2.04 to 2.44; b3 is a constant, which ranges from 0.1224 to 0.1624.

[0089] Example 2:

[0090] This embodiment provides a long-term determination method for roadbed equilibrium humidity, and the specific steps are as follows:

[0091] S1. Calibration of humidity sensor 1 2 and humidity sensor 2 7: Humidity sensor 1 2 and humidity sensor 2 7 collect the volume moisture content within the sensor range of the roadbed soil, which is somewhat different from the moisture content of the roadbed soil. The details are as follows:

[0092] S101, preparing subgrade soil with an optimal moisture content according to compaction degrees of 93%, 94%, and 96% respectively;

[0093] S102, using humidity sensor 1 2 and humidity sensor 2 7 to collect its volume moisture content, establish the relationship between volume moisture content and roadbed soil moisture content, that is, establish a calibration curve, as shown in the attached Figure 4 、 5 As shown in FIG6, the volume moisture content measured by humidity sensor 1 2 and humidity sensor 2 7 can be converted into the moisture content of roadbed soil through the calibration curve.

[0094] The packaging of S2, humidity sensor 1 2 and humidity sensor 2 7 is as follows:

[0095] S201. Moisture sensor 1 2 and moisture sensor 2 7 for measuring roadbed soil of the same compaction degree are respectively enclosed in a PVC cylindrical tube 1 and a PVC cylindrical tube 2 6 with a diameter of 10 cm and a height of 10 cm. The PVC cylindrical tube 1 and the PVC cylindrical tube 2 6 are filled with roadbed soil under construction.

[0096] S202. The filled subgrade soil is controlled according to the compaction degree zone. The physical parameters of the subgrade soil are shown in Table 1.

[0097] Table 1 Physical parameters of roadbed soil

[0098]

[0099] It can be seen from this that the mass of the roadbed soil filled in PVC cylindrical tube 1 and PVC cylindrical tube 2 6 is 1285g of roadbed soil with a compaction degree of 93%, 1299g of roadbed soil with a compaction degree of 94%, and 1326g of roadbed soil with a compaction degree of 96%.

[0100] S203. After placing the roadbed soil and humidity sensor 1 2 or humidity sensor 2 7 into PVC cylindrical tube 1 and PVC cylindrical tube 2 6, cover the ends of PVC cylindrical tube 1 and PVC cylindrical tube 2 6 with plastic cap 1 3 and plastic cap 2 8, respectively. Lead the data line 5 of humidity sensor 1 2 and humidity sensor 2 7 through lead hole 1 4 and lead hole 2 9.

[0101] S204. Wax-seal the entire PVC cylindrical tube 1 of the closed humidity sensor device. Drill holes in the sidewall of the PVC cylindrical tube 2 of the open humidity sensor device. The diameter of the connecting holes 10 is 5 mm, the spacing between adjacent connecting holes 10 is 20 mm, and the connecting holes 10 are evenly distributed on the sidewall of the PVC cylindrical tube 2.

[0102] S3. Burying of the encapsulated closed humidity sensor device and the open humidity sensor device: Place a pair of encapsulated closed humidity sensors and an open humidity sensor on top of the corresponding roadbed before rolling the roadbed soil with a compaction degree of 93%, 94%, and 96%, respectively, and then compact them with a roller, and lead the data lines to the roadside.

[0103] S4. Long-term test of roadbed humidity: collect data from the encapsulated closed humidity sensors and open humidity sensors, and convert them into roadbed moisture content. Figure 4 shown.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A long-term determination method of roadbed equilibrium humidity, characterized in that: The method comprises burying a closed moisture sensor device and an open moisture sensor device on the top of the subgrade of a layered compacted subgrade with a compaction degree of 93%, a compaction degree of 94%, and a compaction degree of 96%, respectively. The subgrade soil moisture is measured once a quarter each year and continuously collected for several years. By comparing the moisture data collected by the closed moisture sensor device and the open moisture sensor device in the subgrade with the corresponding compaction degree, the optimal moisture content of the subgrade soil during construction and the moisture content change of the subgrade soil with environmental changes are obtained, thereby determining the difference in subgrade moisture change and the subgrade equilibrium moisture content. The closed humidity sensor device is filled with the construction subgrade soil of the corresponding compacted subgrade layer to prevent moisture loss; the open humidity sensor device is filled with construction subgrade soil and is connected to the subgrade soil of the corresponding roadbed layer to maintain moisture exchange. The enclosed sensor device includes a PVC cylindrical tube and a humidity sensor. The humidity sensor is installed in the PVC cylindrical tube. Plastic covers are installed at both ends of the PVC cylindrical tube. A lead hole is opened in the center of the plastic cover. The data cable of the humidity sensor is led out of the PVC cylindrical tube through the lead hole. The production process of the closed sensor device is as follows: (1) Fill the PVC cylindrical tube with the subgrade soil of the corresponding layer of compacted subgrade during construction. The filling amount of the subgrade soil of the corresponding layer of compacted subgrade is set according to the compaction degree of the subgrade. (2) When filling the corresponding layer of compacted roadbed soil, place a humidity sensor and perform manual compaction; (3) After placing the corresponding layer of compacted roadbed soil and humidity sensor 1, cover the two ends of the PVC cylindrical tube 1 with plastic covers 1, and lead the data line of the humidity sensor 1 through the lead hole 1; (4) Perform wax sealing on the PVC cylindrical tube as a whole; (5) Place the encapsulated closed humidity sensor device on the top of the roadbed with a compaction degree of 93%, a compaction degree of 94%, and a compaction degree of 96% after the roadbed is mixed and before rolling, and then complete the roadbed rolling; The open humidity sensor device includes a second PVC cylindrical tube and a second humidity sensor. The second humidity sensor is installed in the second PVC cylindrical tube. Two plastic covers are installed at both ends of the second PVC cylindrical tube. A second lead hole is opened in the center of the second plastic cover. The data line of the second humidity sensor is led out of the second PVC cylindrical tube through the second lead hole. A plurality of evenly distributed communication holes are opened on the side wall of the second PVC cylindrical tube. The details of the fabrication process for the open humidity sensor device are as follows: (1) Fill the PVC cylindrical tube 2 with the subgrade soil of the corresponding layer of compacted subgrade during construction. The filling amount of the subgrade soil of the corresponding layer of compacted subgrade is set according to the compaction degree of the subgrade. (2) When filling the corresponding layer of compacted roadbed soil, place the second humidity sensor and perform manual compaction; (3) After placing the corresponding layer of compacted roadbed soil and humidity sensor 2, cover the two ends of the PVC cylindrical tube 2 with plastic covers 2, and lead the data line of humidity sensor 2 through the lead hole 2; (4) The side wall of the PVC cylindrical tube 2 is opened with holes: a number of evenly distributed connecting holes are opened on the side wall of the PVC cylindrical tube 2, the diameter of the connecting holes is 5 mm, and the distance between two adjacent connecting holes is 20 mm; (5) Place the open moisture sensor device on the top of the roadbed with a compaction degree of 93%, a compaction degree of 94%, and a compaction degree of 96% after the roadbed is mixed and before rolling, and then complete the roadbed rolling; The mass of the subgrade soil filled into PVC cylindrical tube 1 and PVC cylindrical tube 2 is calculated based on the degree of compaction, the maximum dry density of the subgrade soil, and the volume of PVC cylindrical tube 1 or PVC cylindrical tube 2 using the following formula: ; Among them, m s Indicates the mass of soil to be filled, in g; Q indicates the degree of compaction; ρ max Indicates the maximum dry density of roadbed soil in g / cm 3 ; is a constant with a value of 3.14; r represents the radius of the bottom surface of the PVC cylindrical tube 1 or PVC cylindrical tube 2, in cm; h represents the radius of the PVC cylindrical tube 1 or PVC cylindrical tube 2, in cm; Before humidity sensor 1 and humidity sensor 2 are installed in the corresponding PVC cylindrical tube 1 and PVC cylindrical tube 2, it is necessary to calibrate the volume moisture content collected by humidity sensor 1 and humidity sensor 2 with the moisture content of the roadbed soil, and establish a calibration curve between the volume moisture content and the moisture content of the roadbed soil; The volume moisture content of the compacted roadbed with a compaction degree of 93% and the moisture content of the roadbed soil satisfy the following formula: y1=a1x1-b1; Where y1 represents the volumetric moisture content of the roadbed with a compaction degree of 93%; x1 represents the moisture content of the roadbed soil with a compaction degree of 93%; a1 represents the correlation coefficient, with a value ranging from 1.47 to 1.87; b1 is a constant, with a value range of 0.0073 to 0.0103; The volume moisture content of the compacted roadbed with a compaction degree of 94% and the moisture content of the roadbed soil satisfy the following formula: y2=a2x2+b2; Where y2 represents the volumetric moisture content of the roadbed with a compaction degree of 94%; x2 represents the moisture content of the roadbed soil with a compaction degree of 94%; a2 represents the correlation coefficient, with a value ranging from 0.992 to 1.392; b2 is a constant, with a value range of 0.0316 to 0.0716; The volume moisture content of the compacted roadbed with a compaction degree of 96% and the moisture content of the roadbed soil satisfy the following formula: y3=a3x3+b3; Among them, y3 represents the volume moisture content of the roadbed at a compaction degree of 96%; x3 represents the moisture content of the roadbed soil at a compaction degree of 96%; a3 represents the correlation coefficient, which ranges from 2.04 to 2.44; b3 is a constant, which ranges from 0.1224 to 0.1624.

2. The long-term determination method of roadbed equilibrium humidity according to claim 1, characterized in that: The construction roadbed soil filled inside the closed moisture sensor device installed on the compacted roadbed with a compaction degree of 93% and the open moisture sensor device is coarse-grained soil.

3. The long-term determination method of roadbed equilibrium humidity according to claim 1, characterized in that: The construction roadbed soil filled inside the closed moisture sensor device installed on the compacted roadbed with a compaction degree of 94% and the open moisture sensor device is coarse-grained soil and fine-grained soil.

4. The long-term determination method of roadbed equilibrium humidity according to claim 1, characterized in that: The construction roadbed soil filled in the closed moisture sensor device installed on the compacted roadbed with a compaction degree of 93% and the open moisture sensor device is cement-improved soil, lime-fly ash-stabilized soil, or lime-improved soil.

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