CN114965174A - Unsaturated soil subgrade water-gas migration characteristic testing device and testing method thereof - Google Patents
Unsaturated soil subgrade water-gas migration characteristic testing device and testing method thereof Download PDFInfo
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Abstract
The application discloses a device and a method for testing moisture migration characteristics of unsaturated soil subgrade, and relates to the technical field of geotechnical engineering. The testing device comprises a model box, a moisture regulating assembly, a first temperature control assembly and a second temperature control assembly, wherein the moisture regulating assembly, the first temperature control assembly and the second temperature control assembly are arranged in the model box; still be provided with humiture measurement subassembly, drainage subassembly and displacement sensor in the model case, displacement sensor is used for detecting the altitude variation of sample, and humiture measurement subassembly is used for measuring the temperature and the humidity of sample in different positions department, and first temperature control subassembly is connected with the drainage subassembly including the device that absorbs water. The influence of water and air migration on the change conditions of the internal performance and the humidity of the roadbed under different working conditions can be simulated, so that the simulation effect is more in line with the engineering practice.
Description
Technical Field
The application relates to the technical field of geotechnical engineering, in particular to a device and a method for testing moisture migration characteristics of an unsaturated soil subgrade.
Background
Moisture is a main factor inducing the occurrence of roadbed defects and deterioration of performance. In actual conditions, the roadbed is affected by climate (rainfall, evaporation), underground water level, pumping action and the like, and the water migration inside the roadbed is usually carried out simultaneously by liquid water and gaseous water. On one hand, the underground water migrates upwards into the roadbed soil body in the form of liquid water under the capillary action; on the other hand, gaseous water in the soil body can also migrate in the pores of the soil body and is condensed into water under the low-temperature action of the surface layer of the top surface of the roadbed.
At present, the research on occurrence change of water inside a roadbed is mainly single-phase liquid water migration, but in some arid regions with deeper underground water burial, the influence of the gas water migration on roadbed filling has a large specific gravity and cannot be ignored. At present, research is carried out on the long-term performance evolution law of the interior of roadbed filling under the action of water and gas migration in China, and because the theoretically related factors are more, the multi-field coupling numerical simulation and theoretical derivation are extremely complex and good calculation results are difficult to obtain, the research on the roadbed water and gas migration law is developed based on indoor tests.
The existing test instrument and equipment simultaneously consider the change rule of the humidity and the performance inside a roadbed soil body in the water-gas migration process mainly from two aspects of temperature (temperature difference) and underground water (fluctuation), have certain deviation with the actual engineering working condition of the roadbed, and cannot accurately simulate the influence rule of the gas-state water migration on the roadbed humidity and the performance under the actual working condition.
Disclosure of Invention
The application aims to provide a device and a method for testing moisture migration characteristics of an unsaturated soil subgrade, which can simulate the influence of moisture migration on the change conditions of the internal performance and the humidity of the subgrade under different working conditions, so that the simulation effect is more in line with the engineering practice.
The embodiment of the application is realized as follows:
in one aspect of the embodiment of the application, a unsaturated soil subgrade moisture migration characteristic testing device is provided, and comprises a model box, and a moisture regulating assembly, a first temperature control assembly and a second temperature control assembly which are arranged in the model box, wherein the first temperature control assembly is used for being arranged at the top of a sample, the second temperature control assembly is used for being arranged at the bottom of the sample, and the moisture regulating assembly is arranged on the second temperature control assembly; still be provided with temperature and humidity measurement subassembly, drainage subassembly and displacement sensor in the model case, displacement sensor is used for detecting the altitude variation of sample, temperature and humidity measurement subassembly is used for measuring the temperature and the humidity of sample in different positions department, first temperature control subassembly is including the device that absorbs water, the device that absorbs water with drainage subassembly is connected.
Optionally, first temperature control subassembly includes first temperature controller, and with the first temperature regulation board that first temperature controller connects, be connected with the heat transfer baffle of range upon range of setting on the first temperature regulation board, first temperature regulation board through rotatable adjusting support piece and one of them the heat transfer baffle is connected, be provided with the through-hole on the heat transfer baffle respectively, two the heat transfer baffle rotates each other, so that the through-hole switches on or ends, first temperature regulation board with rotatable adjusting support piece is formed with the holding cavity, the device that absorbs water is located in the holding cavity.
Optionally, the second temperature control assembly comprises a second temperature controller and a second temperature adjusting plate connected with the second temperature controller, and a cushion block is arranged between the second temperature adjusting plate and the bottom wall of the mold box.
Optionally, the moisture adjusting assembly comprises a water storage tank and a control valve connected with the water storage tank, a water outlet pipe is connected to the control valve, the water outlet pipe is connected with a permeable stone arranged on the second temperature adjusting plate, a first drainage pipe is further connected to the permeable stone, the first drainage pipe is connected with the collecting box, a water stop plate is arranged on the permeable stone, the water stop plate is used for enabling water vapor to pass through and limiting liquid water to pass through, and the water stop plate is used for placing the sample.
Optionally, the temperature and humidity measurement assembly comprises a data acquisition assembly and a plurality of probes connected with the data acquisition assembly, and the plurality of probes are used for being inserted in different positions of the sample in the height direction.
Optionally, the drain assembly comprises a second drain pipe connected to the water absorbing device, and a condensed water collector connected to the second drain pipe.
Optionally, the model box includes the box to and the door body that sets up in one side of box, be provided with transparent viewing aperture on the door body, be provided with the insulating layer on the box, and the via hole, the via hole inner circle is provided with the sealing washer, still be provided with the thermometer in the box, be used for observing the temperature in the box.
In another aspect of the embodiments of the present application, there is provided a method for testing moisture migration characteristics of an unsaturated soil subgrade, where the method is implemented by using the device for testing moisture migration characteristics of an unsaturated soil subgrade as described in any one of the above embodiments, and the method includes:
preparing a roadbed model sample, and wrapping an insulating layer on the outer ring of the sample;
inserting a probe of a temperature and humidity testing assembly into the sample;
placing the specimen on a moisture regulating assembly and a first temperature control assembly on top of the specimen;
correspondingly matching the displacement sensor with the first temperature control assembly;
the first temperature control assembly, the second temperature control assembly and the moisture regulating assembly are respectively regulated;
and recording the data variation of the displacement sensor and the temperature and humidity testing component.
Optionally, the preparing the roadbed model sample comprises:
taking a soil sample to be tested, and carrying out an indoor light compaction test to determine the optimal water content and the maximum dry density of the soil sample;
mixing the samples according to the required standards of compaction degree and water content of the roadbed filler in actual engineering;
and (3) compacting the soil sample by upper and lower layers.
Optionally, the separately adjusting the first temperature control assembly, the second temperature control assembly and the moisture adjustment assembly comprises:
adjusting the temperature of the first temperature control assembly and the second temperature control assembly to provide a temperature differential between the top and bottom of the sample;
and adjusting the flow of water in the moisture regulating assembly for simulating the height of the underground water level.
The beneficial effects of the embodiment of the application include:
the unsaturated soil subgrade water-gas migration characteristic testing device and the testing method thereof provided by the embodiment of the application are convenient for simulating different working condition environments, such as the temperature difference between the subgrade surface layer and the interior, the underground water condition and the like, through the water regulating assembly, the first temperature control assembly and the second temperature control assembly which are arranged in the model box. When data are collected, the temperature and humidity measuring assembly and the displacement sensor are used for measuring the humidity and the temperature inside the soil body in the water and gas migration process, meanwhile, the soil body deformation test analysis is added, and the unsaturated soil subgrade performance evolution rule in the water and gas migration process can be obtained at the same time. In addition, the water absorption device is matched with the water drainage assembly, so that the influence of liquid drop back-seepage on the accuracy of the experiment is avoided. By adopting the form, the roadbed performance evolution law under various working conditions is considered, the whole process simulation of roadbed water and gas migration under various complex environment influences encountered in actual engineering can be truly implemented, the evolution law of properties such as physics, mechanics and deformation in the unsaturated soil roadbed considering the water and gas bidirectional flow process is comprehensively mastered, and powerful theoretical support is provided for the later-stage development of targeted roadbed treatment and roadbed service performance all-round guarantee engineering. And when the influence of water and air migration on the change conditions of the internal performance and the humidity of the roadbed under different working conditions is simulated, the simulation effect is more in line with the engineering practice.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.
Fig. 1 is a schematic structural diagram of a device for testing moisture migration characteristics of an unsaturated soil subgrade provided by an embodiment of the application;
FIG. 2 is a schematic structural view of a first temperature control assembly and a drain assembly according to an embodiment of the present disclosure;
FIG. 3 is a schematic structural diagram of a first temperature control assembly according to an embodiment of the present disclosure;
FIG. 4 is a schematic structural diagram of a mold box provided in an embodiment of the present application;
fig. 5 is a flowchart of a method for testing moisture migration characteristics of an unsaturated soil subgrade according to an embodiment of the application.
Icon: 100-unsaturated soil subgrade water-gas migration characteristic testing device; 110-a mold box; 112-a box body; 114-a door body; 1142-transparent viewing port; 116-a thermal insulation layer; 118-a via hole; 119-a sealing ring; 120-a moisture regulating component; 122-a water storage tank; 124-a control valve; 126-permeable stone; 127-a first drain pipe; 128-a collection bin; 129-a water-stop sheet; 130-a first temperature control assembly; 132-a water absorbing device; 134-a first temperature controller; 136-a first temperature regulation plate; 137-rotatably adjustable support; 138-a heat transfer separator; 1382-a through hole; 140-a second temperature control assembly; 142-a second temperature controller; 144-a second temperature adjustment plate; 150-a temperature and humidity measurement component; 152-a data acquisition component; 154-a probe; 160-a drainage assembly; 162-a second drain; 164-a condensate collector; 170-a displacement sensor; 180-cushion blocks; 190-thermometer.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present application, it should be noted that the terms "inside", "outside", and the like indicate orientations or positional relationships based on orientations or positional relationships shown in the drawings or orientations or positional relationships that the product of the application is usually placed in when used, and are used only for convenience of description and simplification of the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and the like are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.
In the description of the present application, it is also to be noted that, unless otherwise explicitly specified or limited, the terms "disposed" and "connected" are to be interpreted broadly, e.g., as being either fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
The existing test instrument and equipment simultaneously consider the change rule of the humidity and the performance inside a roadbed soil body in the water and gas migration process mainly from two aspects of temperature (temperature difference) and underground water (fluctuation), have certain deviation with the actual engineering working condition of the roadbed, and cannot accurately simulate the influence rule of gaseous water migration on the humidity and the performance of the roadbed under the actual working condition. In view of the above problems, the embodiments of the present application provide the following technical solutions to overcome the above problems.
Referring to fig. 1, the embodiment provides a device 100 for testing moisture migration characteristics of an unsaturated soil subgrade, which includes a model box 110, and a moisture regulating assembly 120, a first temperature control assembly 130 and a second temperature control assembly 140 which are arranged in the model box 110, wherein the first temperature control assembly 130 is arranged on the top of a sample, the second temperature control assembly 140 is arranged on the bottom of the sample, and the moisture regulating assembly 120 is arranged on the second temperature control assembly 140; the model box 110 is further provided with a temperature and humidity measuring assembly 150, a drainage assembly 160 and a displacement sensor 170, the displacement sensor 170 is used for detecting the height variation of the sample, the temperature and humidity measuring assembly 150 is used for measuring the temperature and the humidity of the sample at different positions, the first temperature control assembly 130 comprises a water absorbing device 132, and the water absorbing device 132 is connected with the drainage assembly 160.
Specifically, the model box 110 is mainly used to ensure technical performance and operation safety required in the experiment process, and avoid the influence of external environment in the experiment process. The experiment was conducted by providing a moisture regulating assembly 120 within the model box 110 to facilitate simulation of groundwater. The first temperature control assembly 130 and the second temperature control assembly 140 are mainly used for simulating the condition that the temperature difference exists on the roadbed under the actual working condition. In addition, the temperature and humidity measuring assembly 150 disposed in the mold box 110 is mainly used for measuring the temperature and humidity changes in the sample during the experiment. And the displacement sensor 170 is used to detect the amount of change in the height of the sample so as to know the degree of influence of the change in temperature on the contraction or expansion of the sample.
By connecting the water absorbing device 132 of the first temperature control assembly 130 with the drainage assembly 160, when the experiment of the water vapor migration characteristic is carried out, the water vapor is prevented from seeping downwards after the top layer is condensed to form liquid drops, and the stability during the experiment is favorably ensured. Meanwhile, the water absorbing device 132 is connected to the drain assembly 160 to prevent the water in the water absorbing device 132 from infiltrating after being saturated with water. The water absorbing device 132 may be made of a water absorbing material, which is not particularly limited in the embodiments of the present application.
It should be noted that, in the embodiment of the present application, the number of sets of samples set in the mold box 110 is not specifically limited, and for example, only one set may be set, and two or three sets may also be set, as long as it is ensured that each set of samples has a corresponding device matched therewith. For example, when there are two sets of samples, the first temperature control assembly 130 and the second temperature control assembly 140 need to be provided in two sets.
The unsaturated soil subgrade water-gas migration characteristic testing device 100 provided by the embodiment of the application is convenient for simulating different working condition environments, such as the temperature difference between the surface layer and the inside of a roadbed, the underground water condition and the like, through the water regulating component 120, the first temperature control component 130 and the second temperature control component 140 which are arranged in the model box 110. When data are collected, the temperature and humidity measuring component 150 and the displacement sensor 170 are used for measuring the internal humidity and the internal temperature of the soil body in the water and gas migration process, meanwhile, the soil body deformation test analysis is added, and the unsaturated soil subgrade performance evolution rule in the water and gas migration process can be obtained at the same time. In addition, through the cooperation of the water absorption device 132 and the drainage assembly 160, the influence of the liquid drop back-seepage on the experimental accuracy is avoided. By adopting the form, the evolution law of the performance of the roadbed under various working conditions is considered, the whole process simulation of the roadbed moisture migration under the influence of various complex environments encountered in actual engineering can be truly realized, the evolution law of properties such as physics, mechanics, deformation and the like in the process of considering the bidirectional flow of water and gas of the unsaturated soil roadbed is comprehensively mastered, and powerful theoretical support is provided for the engineering of carrying out targeted roadbed treatment and omnibearing guarantee of the roadbed service performance in the later period. And when the influence of water and air migration on the change conditions of the internal performance and the humidity of the roadbed under different working conditions is simulated, the simulation effect is more in line with the engineering practice.
As shown in fig. 1, 2 and 3, the first temperature control assembly 130 includes a first temperature controller 134 and a first temperature adjustment plate 136 connected to the first temperature controller 134, the first temperature adjustment plate 136 is connected to heat transfer partitions 138 stacked one on another, the first temperature adjustment plate 136 is connected to one of the heat transfer partitions 138 through a rotatable adjustment support 137, the heat transfer partitions 138 are respectively provided with through holes 1382, the two heat transfer partitions 138 rotate with each other to enable the through holes 1382 to be opened or closed, the first temperature adjustment plate 136 and the rotatable adjustment support 137 form an accommodation cavity, and the water absorbing device 132 is located in the accommodation cavity.
Specifically, the first temperature controller 134 is mainly used to control the temperature of the first temperature adjustment plate 136, so as to simulate the actual temperature under different working conditions. It can be understood that when the samples are arranged in two groups, two first temperature adjustment plates 136 may be correspondingly arranged, and the same first temperature control assembly 130 may be used for control. In addition, the drain assembly 160 communicates with the water absorbing device 132 through the rotatable adjusting support 137, and a switch knob may be provided on the rotatable adjusting support 137 so as to control conduction between the water absorbing device 132 and the drain assembly 160.
By providing a heat transfer spacer 138 on the first temperature adjustment plate 136, heat on the first temperature adjustment plate 136 is uniformly transferred to the top of the sample by heat transfer. Meanwhile, the heat transfer partition plates 138 are arranged in a stacked and mutually rotatable mode, and when the actual working condition environment is simulated, the through holes 1382 of the heat transfer partition plates 138 are correspondingly communicated, so that the experimental simulation of the roadbed performance change under the non-closed condition (roadbed is not sealed for drainage or roadbed is not sealed for drainage) can be realized. It will be appreciated that experimental simulations of the change in the performance of the subgrade under closed conditions (subgrade closed with no drainage or subgrade closed with drainage) can be achieved when the through holes 1382 in the heat transfer baffles 138 are misaligned to close. Therefore, the change rules of the temperature and humidity and the like in the roadbed filling under the drainage conditions of different upper roadbed layers can be considered, so that the simulation of the actual working condition can be more comprehensively realized.
As shown in fig. 1, the second temperature control assembly 140 includes a second temperature controller 142, and a second temperature adjustment plate 144 connected to the second temperature controller 142, and a spacer block 180 is disposed between the second temperature adjustment plate 144 and the bottom wall of the mold box 110.
By providing the spacer block 180 between the second temperature adjustment plate 144 and the bottom wall of the mold box 110, the second temperature adjustment plate 144 can be conveniently disposed, and the influence of the mold box 110 on the accuracy of the experiment can be avoided. In order to ensure the stability of the first temperature adjusting plate 136 and the second temperature adjusting plate 144 during use, other areas except the opposite sides of the first temperature adjusting plate and the second temperature adjusting plate are all treated in a mode of wrapping by heat insulating materials and rubber films, so that the temperature is prevented from dissipating, and the accuracy during experiments is ensured. In addition, the temperature variation ranges of the first temperature control assembly 130 and the second temperature control assembly 140 are both-30 ℃ to 60 ℃ (the temperature deviation is ± 0.01 ℃, and the temperature fluctuation degree is not more than ± 0.01 ℃). Target temperature, temperature duration, temperature change mode and the like in the test process can be set on the first temperature controller 134 and the second temperature controller 142 which are externally connected through the model box 110, so that the change of the working condition environment can be better simulated.
As shown in fig. 1, the moisture adjusting assembly 120 includes a water storage tank 122 and a control valve 124 connected to the water storage tank 122, the control valve 124 is connected to a water outlet pipe, the water outlet pipe is connected to a permeable stone 126 disposed on a second temperature adjusting plate 144, the permeable stone 126 is further connected to a first water outlet pipe 127, the first water outlet pipe 127 is connected to a collection tank 128, a water stop plate 129 is disposed on the permeable stone 126, the water stop plate 129 is used for allowing water vapor to pass through, so as to limit liquid water from passing through, and the water stop plate 129 is used for placing a sample.
Specifically, the control valve 124 is connected to the water storage tank 122 so as to control the water replenishing amount, the water replenishing speed, the water replenishing time, the controllable water replenishing interval time and the like. The whole water supply adopts a non-pressure water supply mode, and when the water in the water storage tank 122 is insufficient, the water is supplemented into the water storage tank 122. Groundwater conditions are simulated by connecting the outlet pipe to the permeable stone 126 so as to wet the permeable stone 126. In addition, the water stop sheet 129 is arranged on the permeable stone 126 to allow water vapor to pass through and limit liquid water to pass through, so that the water vapor migration characteristic of the unsaturated soil subgrade is better simulated. During the experiment, water overflows from the lower part of the sample, and the water can be drained through the first drainage pipe 127 connected with the permeable stone 126.
It is understood that the water-stop sheet 129 may not be disposed on the water-permeable stone 126, so as to realize the respective migration of water and gas at the bottom of the sample and the joint migration process through different arrangement forms. By adopting the form, conditions are provided for simulating the actual conditions of the water-gas migration rule in arid areas, rainless areas and areas with deep underground water burial, and basic data support is provided for researching the water-gas migration rule.
As shown in fig. 1, the temperature and humidity measuring assembly 150 includes a data collecting assembly 152, and a plurality of probes 154 connected to the data collecting assembly 152, wherein the plurality of probes 154 are configured to be inserted into different positions of the sample in the height direction.
For example, in the experiment, one probe 154 may be disposed every 5cm from top to bottom along the height direction of the sample, and the probe 154 may be a corrosion-resistant electrode to ensure the reliability of the measurement. In addition, the displacement sensor 170 may also be connected to the data acquisition assembly 152, so as to perform data acquisition on the temperature, humidity and displacement variation monitored in real time through the data acquisition assembly 152, thereby facilitating the sorting and analysis.
As shown in fig. 2, the drain assembly 160 includes a second drain pipe 162 connected to the water absorbing device 132, and a condensed water collector 164 connected to the second drain pipe 162 to collect the moisture adsorbed by the water absorbing device 132.
As shown in fig. 4, the mold box 110 includes a box body 112 and a door body 114 disposed on one side of the box body 112, the door body 114 is provided with a transparent viewing port 1142, the box body 112 is provided with a heat insulation layer 116 and a via hole 118, a sealing ring 119 is disposed on an inner ring of the via hole 118, and a thermometer 190 is further disposed in the box body 112 for observing a temperature in the box body 112.
Specifically, the mold box 110 should meet the requirements for achieving the technical performance and the operation safety protection, and achieve the functions of heat insulation, heat preservation and moisture preservation. For thermal insulation and heat preservation, steel plate-wrapped insulation (i.e., insulation layer 116 provided on the box body 112) may be used as a means for isolating the temperature exchange between the test mold box 110 and the outside temperature. In addition, in order to meet the visualization requirement during the experiment, the transparent viewing port 1142 can be made of transparent resin, aerogel plate and glass, and the visualization requirement can be met under the condition of ensuring sealing.
In addition, the door 114 arranged on one side of the box body 112 is convenient for opening and closing the door on the side surface and taking and placing samples. By providing the through-hole 118 in the housing 112, various data collection lines can be easily accessed into the test chamber to facilitate simulation of the operating conditions and data collection. The thermometer 190 arranged in the box body 112 can observe the ambient temperature in the box body 112, and the influence on the accuracy of the experimental result due to the fluctuation of the ambient temperature in the box body 112 is avoided. For example, to eliminate the effect of temperature on the experimental results, the temperature inside the box 112 may be kept at 25 ℃, and the thermometer 190 is used to observe whether the ambient temperature inside the box 112 meets the requirements.
As shown in fig. 5, the embodiment of the present application further discloses a method for testing moisture migration characteristics of an unsaturated soil subgrade, which is performed by using the device 100 for testing moisture migration characteristics of an unsaturated soil subgrade in the foregoing embodiment, and the method includes:
s100, preparing a roadbed model sample, and wrapping an insulating layer on the outer ring of the sample.
Specifically, the road bed model sample can be prepared for cylindrically, in order to save test time and can contrast the observation, carries out two sets of parallel test respectively, in order to reduce the size effect of sample as far as possible, every group sample size all sets up to diameter 15cm, highly is 35 cm's cylinder, also can set up to other sizes according to actual need, and this application embodiment does not do specific restriction to this. When the heat preservation layer is arranged, a rubber film can be wrapped around the cylindrical sample, a flexible heat preservation material can be wrapped around the cylindrical sample, and a rubber film can be wrapped on the outermost layer of the cylindrical sample. By adopting the mode, the influence of the air temperature in the model box 110 on the sample temperature can be reduced, and the unidirectional temperature control is realized to the maximum extent. Meanwhile, the double-layer rubber film can effectively ensure the smoothness and full contact of the heat-insulating material, and the heat-insulating material is flexibly compressed to achieve a better heat-insulating effect. The arrangement form of the three-layer interlayer of the rubber film, the flexible heat-insulating material and the rubber film can well realize heat insulation and unidirectional temperature control, and has good experimental effect.
S200, inserting the probe 154 of the temperature and humidity testing assembly into the sample.
S300, the sample is placed on the moisture regulating member 120, and the first temperature control member 130 is placed on top of the sample.
And S400, correspondingly matching the displacement sensor 170 with the first temperature control assembly 130.
And S500, respectively adjusting the first temperature control assembly 130, the second temperature control assembly 140 and the moisture adjusting assembly 120.
S600, recording data variation of the displacement sensor 170 and the temperature and humidity testing component.
By adopting the mode, the water vapor migration process in the actual roadbed engineering can be well simulated, and the roadbed water vapor migration rule under different temperature gradients, different groundwater conditions, different unsaturated soil roadbed fillers and initial filling conditions can be intuitively obtained. The test cost is low, the economic benefit is great, the distribution conditions of the variation of the humidity, the deformation and the temperature of the unsaturated soil roadbed under various water vapor migration conditions can be obtained, the roadbed engineering construction design can be effectively guided, and the engineering safety is improved.
In an alternative embodiment of the present application, preparing the roadbed model sample comprises:
s110, taking a soil sample to be tested, and carrying out an indoor light compaction test to determine the optimal water content and the maximum dry density of the soil sample.
And S120, mixing the sample according to the required standards of the compaction degree and the water content of the roadbed filler in actual engineering.
And S130, compacting the soil sample by an upper layer and a lower layer.
Specifically, after the optimal water content and the maximum dry density of the soil sample are determined, the sample can reach the optimal compaction degree, and therefore the experimental effect is guaranteed. In the compaction process, the soil sample is compacted on the upper side and the lower side, so that the roadbed and the embankment are simulated, and the matching of the experimental process and the actual working condition is ensured.
In an alternative embodiment of the present application, adjusting the first temperature control assembly 130, the second temperature control assembly 140, and the moisture adjustment assembly 120, respectively, comprises:
s510, adjusting the temperature of the first temperature control assembly 130 and the second temperature control assembly 140 so that the top and the bottom of the sample have a temperature difference;
and S520, adjusting the flow of water in the moisture adjusting assembly 120 to simulate the height of the underground water level.
Specifically, in practical engineering, a drainage layer is generally arranged below a road surface structure and above a roadbed top layer, and the change and the difference of soil humidity of a soil body on the top of a road foundation under the working condition of drainage or no drainage are not considered by the conventional test instrument. In order to make the test closer to the engineering practice, the underground liquid water migration caused by capillary action is prevented by arranging the water stop sheet 129, the migration of gaseous water is not prevented, and the influence rule of the migration of the gaseous water on the roadbed humidity and the performance is independently and effectively obtained through the first temperature control assembly 130 and the second temperature control assembly 140. In addition, the first temperature control assembly 130 is coupled to the water absorbing device 132 through the heat transfer partition 138 and communicates with the drain assembly 160 to monitor the amount of water output. Meanwhile, the flow of water in the water adjusting assembly 120 is adjusted to simulate the height of the ground water level, so as to simulate different working conditions.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (10)
1. The unsaturated soil subgrade moisture migration characteristic testing device is characterized by comprising a model box, and a moisture regulating assembly, a first temperature control assembly and a second temperature control assembly which are arranged in the model box, wherein the first temperature control assembly is used for being arranged at the top of a sample, the second temperature control assembly is used for being arranged at the bottom of the sample, and the moisture regulating assembly is arranged on the second temperature control assembly; still be provided with temperature and humidity measurement subassembly, drainage subassembly and displacement sensor in the model case, displacement sensor is used for detecting the altitude variation of sample, temperature and humidity measurement subassembly is used for measuring the temperature and the humidity of sample in different positions department, first temperature control subassembly is including the device that absorbs water, the device that absorbs water with drainage subassembly is connected.
2. The unsaturated soil subgrade moisture migration characteristic testing device of claim 1, wherein the first temperature control assembly comprises a first temperature controller and a first temperature adjusting plate connected with the first temperature controller, the first temperature adjusting plate is connected with heat transfer clapboards arranged in a stacked mode, the first temperature adjusting plate is connected with one of the heat transfer clapboards through a rotatable adjusting support, through holes are formed in the heat transfer clapboards respectively, the two heat transfer clapboards rotate mutually to enable the through holes to be communicated or cut off, a containing cavity is formed by the first temperature adjusting plate and the rotatable adjusting support, and the water absorbing device is located in the containing cavity.
3. The unsaturated soil subgrade moisture migration characteristic testing device of claim 1 or 2, wherein the second temperature control assembly comprises a second temperature controller and a second temperature adjusting plate connected with the second temperature controller, and a cushion block is arranged between the second temperature adjusting plate and the bottom wall of the model box.
4. The unsaturated soil subgrade water-air migration characteristic testing device of claim 3, wherein the water regulating component comprises a water storage tank and a control valve connected with the water storage tank, a water outlet pipe is connected with the control valve, the water outlet pipe is connected with a water permeable stone arranged on the second temperature regulating plate, a first water drainage pipe is further connected with the water permeable stone, the first water drainage pipe is connected with the collecting tank, a water stop plate is arranged on the water permeable stone, the water stop plate is used for allowing water-air to pass through and limiting liquid water to pass through, and the water stop plate is used for placing the sample.
5. The unsaturated soil subgrade water-gas migration characteristic testing device of claim 1 or 2, wherein the temperature and humidity measuring component comprises a data acquisition component and a plurality of probes connected with the data acquisition component, and the plurality of probes are used for being inserted at different positions of the sample in the height direction.
6. The unsaturated soil subgrade water-gas migration characteristic testing device of claim 1 or 2, characterized in that the drainage assembly comprises a second drainage pipe connected with the water absorption device and a condensed water collector connected with the second drainage pipe.
7. The unsaturated soil subgrade water-gas migration characteristic testing device of claim 1 or 2, wherein the model box comprises a box body and a door body arranged on one side of the box body, a transparent observation port is arranged on the door body, a heat insulation layer and a through hole are arranged on the box body, a sealing ring is arranged on the inner ring of the through hole, and a thermometer is further arranged in the box body and used for observing the temperature in the box body.
8. A method for testing the moisture migration characteristics of an unsaturated soil subgrade, which is characterized by adopting the moisture migration characteristics testing device of any one of claims 1 to 7, and comprises the following steps:
preparing a roadbed model sample, and wrapping an insulating layer on the outer ring of the sample;
inserting a probe of a temperature and humidity testing assembly into the sample;
placing the specimen on a moisture regulating assembly and a first temperature control assembly on top of the specimen;
correspondingly matching the displacement sensor with the first temperature control assembly;
the first temperature control assembly, the second temperature control assembly and the moisture regulating assembly are respectively regulated;
and recording the data variation of the displacement sensor and the temperature and humidity testing component.
9. The method for testing the water-gas migration characteristics of the unsaturated soil subgrade according to the claim 8, wherein the preparation of the subgrade model sample comprises the following steps:
taking a soil sample to be tested, and carrying out an indoor light compaction test to determine the optimal water content and the maximum dry density of the soil sample;
mixing the samples according to the required standards of compaction degree and water content of the roadbed filler in actual engineering;
and (3) compacting the soil sample by upper and lower layers.
10. The unsaturated soil subgrade moisture migration characteristic testing method of claim 8 or 9, wherein the respectively adjusting the first temperature control assembly, the second temperature control assembly and the moisture adjusting assembly comprises:
adjusting the temperature of the first temperature control assembly and the second temperature control assembly to make the top and the bottom of the sample have a temperature difference;
and adjusting the flow of water in the moisture regulating assembly for simulating the height of the underground water level.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115653820A (en) * | 2022-10-25 | 2023-01-31 | 北京航空航天大学 | Power generation method utilizing pot cover effect |
| CN116297026A (en) * | 2023-03-09 | 2023-06-23 | 北京航空航天大学 | Tester for researching migration rule of pot cover effect gaseous water in soil and using method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115653820A (en) * | 2022-10-25 | 2023-01-31 | 北京航空航天大学 | Power generation method utilizing pot cover effect |
| CN115653820B (en) * | 2022-10-25 | 2024-06-11 | 北京航空航天大学 | Power generation method utilizing pot cover effect |
| CN116297026A (en) * | 2023-03-09 | 2023-06-23 | 北京航空航天大学 | Tester for researching migration rule of pot cover effect gaseous water in soil and using method thereof |
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