CN110108748B - Frost heaving experimental device - Google Patents
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- CN110108748B CN110108748B CN201910490231.8A CN201910490231A CN110108748B CN 110108748 B CN110108748 B CN 110108748B CN 201910490231 A CN201910490231 A CN 201910490231A CN 110108748 B CN110108748 B CN 110108748B
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- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
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Abstract
A frost heaving experiment apparatus, comprising: the device comprises a sample container, a cold end cover and a normal temperature end cover are arranged on the sample container, and a rock soil sample is filled in the sample container; the refrigeration system comprises a refrigeration unit, the refrigeration unit comprises a cold quantity release pipeline, and the cold quantity release pipeline is arranged on the cold end cover; the freezing frontal surface migration detection system comprises a power supply, wherein the power supply comprises a positive end and a negative end, and an ammeter and a voltmeter are connected in series and in parallel with the power supply. The length of the frozen rock and soil can be measured through a freezing frontal surface migration detection system by measuring the rock and soil filling length, the normal-temperature rock and soil density, the frozen rock and soil density, the current value and the voltage value, so that the migration parameters of the freezing frontal surface are obtained. The invention can carry out comprehensive and systematic research on frost heaving effect caused in freezing construction engineering, and provides reference basis for further popularization and application of the manual layer freezing method.
Description
Technical Field
The invention relates to the technical field of civil engineering experimental equipment, in particular to a frost heaving experimental device.
Background
The artificial stratum freezing method is a special construction technology which utilizes an artificial refrigeration technology to freeze water in the stratum, change natural rock-soil bodies into frozen soil, increase the strength and stability of the frozen soil, isolate the connection between underground water and underground engineering and ensure the digging and laying construction of coal mine shafts or underground engineering.
Before the artificial stratum freezing method is implemented, frost heaving experiments need to be carried out on rock and soil to obtain frost heaving parameters of the rock and soil, so that an optimal construction scheme is determined. The frost heaving experimental device used in the prior art can only freeze rock and soil and can obtain rock and soil property parameters after freezing.
Because the existing frost heaving experimental device cannot acquire the temperature field change, the stress field change and the moisture migration condition of rock and soil in the freezing process, if the existing frost heaving experimental device only depends on the property parameters of the frozen rock and soil, the physical property change of the rock and soil in the freezing process cannot be comprehensively reflected, and then the existing frost heaving experimental device cannot provide support for the perfection of the manual layer freezing method.
Disclosure of Invention
In conclusion, how to provide a frost heaving experimental device capable of acquiring migration parameters of a rock-soil freezing frontal surface in a rock-soil freezing process becomes a problem to be solved urgently by technical personnel in the field.
In order to achieve the above purpose, the invention provides the following technical scheme:
a frost heaving experiment apparatus, comprising:
the rock-soil sample loading device comprises a sample container for loading a rock-soil sample, wherein a cold end window and a normal temperature end window are arranged on the sample container, the cold end window is arranged opposite to the normal temperature end window, a cold end cover is arranged on the cold end window, and a normal temperature end cover is arranged on the normal temperature end window;
the refrigerating system comprises a refrigerating unit for providing cold, the refrigerating unit comprises a cold release pipeline, and the cold release pipeline is arranged on the cold end cover and used for releasing cold;
freezing frontal surface migration detecting system, freezing frontal surface migration detecting system is including the power, the power is including positive terminal and negative pole end, the positive terminal and the negative pole end branch is located the cold junction end cover with on the normal atmospheric temperature end cover, be used for right the cold junction window and rock soil sample loading positive pole electric current and the negative pole electric current of normal atmospheric temperature end window department, with the power series has ampere meter, parallel connection has the voltmeter.
Preferably, the positive electrode end is provided with a positive electrode gasket, and the positive electrode gasket is arranged on the cold end cover or the normal temperature end cover; the negative electrode end is provided with a negative electrode gasket, and the negative electrode gasket is arranged on the normal temperature end cover or the cold end cover.
Preferably, the power supply is a dc power supply.
Preferably, the invention also comprises a normal temperature system; the normal temperature system comprises a water pump for outputting normal temperature water flow, a normal temperature water pipe is connected with a water outlet of the water pump, and the normal temperature water pipe is arranged on the normal temperature end cover.
Preferably, the sample container has a cylindrical structure with a cross section having a regular shape.
Preferably, the cold energy release pipeline is of a spiral coil structure and is arranged on the inner side surface of the cold end cover; the normal temperature water pipe is of a spiral coil structure and is arranged on the inner side surface of the normal temperature end cover.
Preferably, the invention also comprises a comprehensive parameter acquisition system, wherein the comprehensive parameter acquisition system comprises a data acquisition analyzer; the comprehensive parameter acquisition system further comprises a temperature information acquisition assembly for acquiring the temperature information of the rock and soil sample, and the temperature information acquisition assembly is in signal connection with the data acquisition analyzer and is arranged in the sample container.
Preferably, the comprehensive parameter acquisition system further comprises a moisture information acquisition component for acquiring moisture information of the rock-soil sample, and the moisture information acquisition component is in signal connection with the data acquisition analyzer and is arranged in the sample container.
Preferably, the comprehensive parameter acquisition system further comprises a stress-strain information acquisition component for acquiring stress-strain information of the geotechnical sample, and the stress-strain information acquisition component is in signal connection with the data acquisition analyzer and is arranged in the sample container.
Preferably, the temperature information acquisition component, the moisture information acquisition component and the stress-strain information acquisition component form a detection unit; and an installation rod is arranged in the sample container from the cold end window to the normal temperature end window, and the detection unit is arranged on the installation rod.
The invention has the following beneficial effects:
the invention provides a frost heaving experiment device which comprises a sample container, wherein a cold end window and a normal temperature end window are arranged on the sample container, a cold end cover is arranged on the cold end window, a normal temperature end cover is arranged on the normal temperature end window, and a rock soil sample is filled in the sample container. The frost heaving experiment device further comprises a freezing system, wherein the freezing system comprises a freezing unit for providing cold, the freezing unit comprises a cold release pipeline, the cold release pipeline is arranged on the cold end cover and used for releasing cold, and the freezing system releases cold to one end of the rock-soil sample, so that rock-soil frost heaving is realized. This frozen swelling experimental apparatus is still including freezing frontal surface migration detecting system, freezing frontal surface migration detecting system is including the power, the power is including positive terminal and negative pole end, the positive terminal and the negative pole end is divided and is located the cold junction end cover and normal atmospheric temperature end cover is last, be used for right the cold junction window and the ground sample loading positive electric current and the negative pole electric current of normal atmospheric temperature end window department, with the power series has ampere meter, parallel connection has the voltmeter. The length of the frozen rock and soil can be measured through a freezing frontal surface migration detection system by measuring the rock and soil filling length, the normal-temperature rock and soil resistivity, the frozen rock and soil resistivity, the current value and the voltage value, so that the migration parameters of the freezing frontal surface are obtained. Through the structural design, the invention can simulate the frost heaving effect of the soil body in the freezing construction process, namely simulate the variation trend of the frost heaving pressure in the freezing process, acquire the water migration parameters in the soil layer in the freezing process, carry out comprehensive and systematic research on the frost heaving effect caused in the freezing construction engineering and provide a reference basis for further popularization and application of the manual layer freezing method.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. Wherein:
FIG. 1 is an equivalent circuit diagram of a freezing front migration detection system when performing a frost heaving experiment;
FIG. 2 is a schematic structural diagram of a frost heaving experiment apparatus according to an embodiment of the present invention;
FIG. 3 is a schematic view of a mounting bar according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of the structure of a sample vessel in an embodiment of the present invention;
FIG. 5 is a schematic structural view of a cold end cap in an embodiment of the invention;
FIG. 6 is a schematic structural diagram of a normal temperature end cap according to an embodiment of the present invention;
description of reference numerals:
a sample container 1, a cold end cover 2, a normal temperature end cover 3, a freezing unit 4, a cold quantity release pipeline 5, a liquid inlet 5a, a liquid outlet 5b, a power supply 6, an ammeter 7, a voltmeter 8, a water pump 9,
The device comprises a data acquisition analyzer 10, a detection unit 11, a mounting rod 12, a normal-temperature water pipe 13, an inlet end 13a, an outlet end 13b, a liquid inlet main pipe 14 and a liquid outlet main pipe 15.
Detailed Description
The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. The various examples are provided by way of explanation of the invention, and not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment, can be used with another embodiment to yield a still further embodiment. It is therefore intended that the present invention encompass such modifications and variations as fall within the scope of the appended claims and equivalents thereof.
In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are for convenience of description of the present invention only and do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. The terms "connected" and "connected" used herein should be interpreted broadly, and may include, for example, a fixed connection or a detachable connection; they may be directly connected or indirectly connected through intermediate members, and specific meanings of the above terms will be understood by those skilled in the art as appropriate.
Referring to fig. 1 to 6, fig. 1 is an equivalent circuit diagram of a freezing front migration detection system during a frost heaving experiment; FIG. 2 is a schematic structural diagram of a frost heaving experiment apparatus according to an embodiment of the present invention; FIG. 3 is a schematic view of a mounting bar according to an embodiment of the present invention; FIG. 4 is a schematic diagram of the structure of a sample vessel in an embodiment of the present invention; FIG. 5 is a schematic structural view of a cold end cap in an embodiment of the invention; fig. 6 is a schematic structural view of a normal temperature end cap according to an embodiment of the present invention.
In order to solve the problems in the prior art, the invention provides a frost heaving experiment device considering moisture migration, which can quantitatively represent the change trends of a moisture field, a temperature field, a stress field and strain and the migration of a freezing front in the manual freezing process, and further quantitatively research the frost heaving effect.
Therefore, the invention provides a frost heaving experiment device which is used for realizing a freezing experiment of rock and soil.
In the present invention, the frost heaving experimental apparatus includes a sample container 1 for loading a rock-soil sample. The sample vessel 1 is made of a metal material, preferably steel. The vertical cross section of the sample container 1 is a regular shape, for example, a circle, an ellipse, a rectangle, a regular polygon, or the like. In addition, the sample container 1 is of a cylindrical structure, such as a cylinder shape, an elliptical cylinder shape and the like, so that the rock-soil sample is loaded in the sample container 1, and the consistency of the compactness of the rock-soil sample can be ensured when the rock-soil sample is pressed.
The cold end window and the normal temperature end window are arranged on the sample container 1, the cold end window and the normal temperature end window are arranged oppositely, and when the sample container 1 is of a cylindrical structure, the cold end window and the normal temperature end window are respectively arranged at two ends of the sample container 1. The cold end window is provided with a cold end cover 2, the normal temperature end window is provided with a normal temperature end cover 3, the cold end window is sealed by the cold end cover 2, and the normal temperature end window is sealed by the normal temperature end cover 3.
In the invention, the cold end cover 2 can be screwed on the cold end window in a threaded connection mode and can also be buckled on the cold end window in a splicing mode; the normal temperature end cover 3 is screwed on the normal temperature end window in a threaded connection mode, and can also be buckled on the normal temperature end window in an insertion connection mode. The cold end cover 2 and the normal temperature end cover 3 are made of metal materials, and specifically, the cold end cover 2 and the normal temperature end cover 3 are made of No. 45 steel.
The rock soil is loaded in the sample container 1, and during a freezing experiment, property parameters of the rock soil need to be acquired, so that various sensors are further arranged in the sample container 1, and signals acquired by the sensors are output by a measuring cable, therefore, the sample container 1 is provided with the lead ports for the measuring cable to pass through, and in a preferred embodiment of the invention, the two lead ports are respectively arranged close to the cold end window and the normal temperature end window.
In the invention, the frost heaving experimental device comprises a freezing system for releasing cold to the rock-soil sample to realize freezing of the rock-soil sample.
Specifically, the refrigerating system comprises a refrigerating unit 4 for providing cold energy, the refrigerating unit 4 is composed of a compressor, an evaporator, a condenser and other equipment, the evaporator performs heat exchange to output a low-temperature refrigerant medium, wherein the refrigerant medium is CaCl2A solution and/or an alcohol, preferably an alcohol.
The refrigerating unit 4 comprises a cold quantity release pipeline 5, and the cold quantity release pipeline 5 is arranged on the cold end cover 2 and used for releasing cold quantity. The cold quantity release pipeline 5 is a metal pipe, preferably a copper pipe or a copper alloy pipe, the cold quantity release pipeline 5 is arranged on the cold end cover 2 in a spiral coil structure, a liquid inlet 5a of the cold quantity release pipeline 5 extends out of the outer edge of the cold end cover 2, and a liquid outlet 5b of the cold quantity release pipeline 5 extends out of a position close to the central point of the cold end cover 2. The cold quantity release pipeline 5 exchanges heat with the evaporator, and cold media circulating in the cold quantity release pipeline 5 can absorb cold quantity and then release the cold quantity to the rock soil sample.
The refrigerating machine of the refrigerating unit 4 is connected with a liquid inlet 5a of the cold energy release pipeline 5 through a liquid inlet main pipe 14, and a liquid outlet 5b of the cold energy release pipeline 5 is connected with the refrigerating machine through a liquid outlet main pipe 15; so that the refrigerant flows back into the refrigerator from the refrigerator through the liquid inlet main pipe 14, the liquid inlet 5a, the cold energy releasing pipeline 5, the liquid outlet 5b and the liquid outlet main pipe 15 to form a circulation.
In the invention, the frost heaving experiment device comprises a normal temperature system for keeping the rock and soil at normal temperature at the position in a normal temperature end window. Wherein, the normal temperature system is connected with normal temperature water pipe 13 including the water pump 9 that is used for exporting normal temperature rivers with the delivery port of water pump 9, and normal temperature water pipe 13 sets up on normal temperature end cover 3 for provide normal atmospheric temperature environment for the ground sample. The normal-temperature water pipe 13 is a metal pipe, preferably a copper pipe or a copper alloy pipe, the normal-temperature water pipe 13 is arranged on the normal-temperature end cover 3 in a spiral coil structure, an inlet end 13a of the normal-temperature water pipe 13 extends out from the outer edge of the normal-temperature end cover 3, and an outlet end 13b of the normal-temperature water pipe 13 extends out from a position close to the central point of the normal-temperature end cover 3. The water circulating in the normal temperature water pipe 13 can exchange heat with the rock and soil sample to maintain the temperature of the rock and soil sample at normal temperature.
The water pump 9 is preferably a variable frequency water pump, and the flow control precision of the water pump for normal temperature water flow is high.
In the actual rock-soil freezing operation, the rock-soil gradually begins to freeze from a state approaching constant temperature by taking the cold release pipeline 5 as a center, and in order to enable the rock-soil sample to be closer to the natural state, the normal temperature system is arranged, and the cold or heat is provided by the normal temperature system to change the temperature of the rock-soil sample so as to enable the rock-soil sample to be closer to the natural state.
In the invention, the frost heaving experiment device comprises a freezing frontal migration detection system for detecting the migration of the freezing frontal.
Specifically, freezing frontal migration detecting system is including power 6, and power 6 is including positive terminal and negative pole end, and positive terminal and negative pole end are located cold junction end cover 2 and normal atmospheric temperature end cover 3 on separately, are used for loading positive electrode current and negative pole electric current to the ground sample of cold junction window department and normal atmospheric temperature end window department, and it has ampere meter 7, parallelly connected voltmeter 8 to establish ties with power 6.
Since the composition and properties of rock soil in a certain region are substantially consistent, the resistivity ρ of rock soil in this region is naturally constant2It can be considered that the resistivity ρ of the rock and soil in this region is uniform in the frozen state1Is also considered to be identical, ρ1≠ρ2。
After a certain area is selected, ohm's law shows that:
U＝I·(R1+R2)
the above formula is more specifically expressed as:
it is known that
Thus, it is possible to provide
Deducing
In the above equation, U, I can be measured by voltmeter 8 and ammeter 7, ρ1、ρ2Is the resistivity (which is approximately constant), S is the cross-sectional area of the sample, R0The initial total resistance of the sample when unfrozen, U, I, ρ1、ρ2And S are known parameters, l0Is the full length of the sample,/1Is the length of the freezing zone, /)2Is the unfrozen zone length; by the above equation, l can be calculated1Length change of l1The change in length of (c) represents the migration of the freezing front.
Specifically, the positive electrode end is provided with a positive electrode gasket, and the positive electrode gasket is arranged on the cold end cover 2 or the normal temperature end cover 3; the negative end is provided with a negative gasket, and the negative gasket is arranged on the normal temperature end cover 3 or the cold end cover 2; the power supply 6 is a dc power supply. The positive electrode gasket and the negative electrode gasket are iron gaskets and are arranged on the inner side surfaces of the end covers (the cold end cover 2 and the normal temperature end cover 3).
In the process of simulating frost heaving, the resistivity of the frozen soil body and the unfrozen soil body is different due to water migration, and the length l of the frozen soil body can be seen from the rule1The ratio of the voltage to the current is linear, and the frozen soil body l can be measured by recording and processing the voltage and current data1This is the location of the freezing front. In the process of carrying out the frost heaving experiment, data of a voltmeter and data of an ammeter are recorded, and the experimental data are processed.
In the invention, the frost heaving experimental device comprises a comprehensive parameter acquisition system, and the comprehensive parameter acquisition system comprises a data acquisition analyzer 10.
The comprehensive parameter acquisition system comprises a temperature monitoring subsystem, a stress monitoring subsystem, a moisture monitoring subsystem and a strain monitoring subsystem. The invention selects a TDS630 data acquisition instrument to acquire temperature, stress and strain, and adopts a moisture acquisition instrument to acquire moisture information.
Specifically, the temperature monitoring subsystem comprises a temperature information acquisition component for acquiring temperature information of the rock and soil sample, and the temperature information acquisition component is in signal connection with the data acquisition analyzer 10 and is arranged in the sample container 1.
Specifically, the moisture monitoring subsystem comprises a moisture information acquisition component for acquiring moisture information of the rock and soil sample, and the moisture information acquisition component is in signal connection with the data acquisition analyzer 10 and is arranged in the sample container 1.
Specifically, the stress monitoring subsystem comprises a stress information acquisition component for acquiring the stress information of the rock-soil sample, and the stress information acquisition component is in signal connection with the data acquisition analyzer 10 and is arranged in the sample container 1.
Specifically, the strain monitoring subsystem comprises a strain information acquisition component for acquiring stress strain information of a rock-soil sample (in a freezing process), and the strain information acquisition component is in signal connection with the data acquisition analyzer 10 and is arranged in the sample container 1.
The temperature information acquisition component comprises a temperature data acquisition instrument and a constantan-copper thermocouple string, the temperature data acquisition instrument is connected with the thermocouple string through a measuring line, and the constantan-copper thermocouple string is wound on the mounting rod 12 and used for measuring the temperature inside the experimental soil body in the sample container 1.
The moisture information acquisition assembly comprises a moisture sensor and a moisture data acquisition instrument, the moisture data acquisition instrument is connected with the moisture sensor through a measuring line, and the moisture sensor is installed on the installation rod 12 and used for measuring the moisture content in the soil body in the measuring device.
The stress information acquisition assembly comprises a stress data acquisition instrument and a stress meter, the stress data acquisition instrument and a stress measuring element are connected through a measuring line, and the stress measuring element is arranged on the mounting rod 12 and used for measuring the stress in the soil body in the device;
the strain information acquisition assembly comprises a strain gauge and a strain data acquisition instrument, the strain data acquisition instrument is connected with the strain gauge through a measuring line, and the strain gauge is installed on the installation rod 12 and used for acquiring strain information of a rock-soil sample (in a freezing process).
The above-described respective sensors are mounted on the mounting rod 12 in the following manner: the installation rod 12 is horizontally placed in the sample container 1, and two end parts of the installation rod 12 respectively extend out of the cold end cover 2 and the normal temperature end cover 3. A measuring line is arranged on the mounting rod 12, the measuring line is positioned on a transverse central axis of the sample container 1, five measuring points are arranged along the length direction of the mounting rod 12, a group of detecting units 11 are arranged on each measuring point, and four sensors (thermocouples, moisture sensors, stress measuring elements and strain gauges) arranged in the detecting units 11 are arranged at equal intervals around the circumference of the mounting rod 12. When the mounting rod 12 is a rectangular parallelepiped structure, four sensors are respectively provided on 4 side surfaces (excluding both end surfaces) of the rectangular parallelepiped.
For the measurement of the migration of the frozen frontal surface, the invention is provided with two iron gaskets, an external power supply 6, a voltmeter 8 and an ammeter 7, wherein the two iron gaskets are respectively fixed on the inner side surfaces of the two end covers, the external power supply 6 and the ammeter 7 are connected in series by wires on the two iron gaskets, and the two iron gaskets are connected in parallel with the voltmeter 8 to form a closed loop; used to test the location of the moisture migration freezing front during freezing.
The material of the sample container 1, the cold end cover 2, the normal temperature end cover 3 and the installation rod 12 in the experimental device is preferably 45#And (3) steel.
The experimental method is as follows:
(1) assembling an experimental device, arranging temperature, moisture, stress and strain testing elements on an installation rod 12, placing the installation rod 12 into a sample container 1, leading out a measuring line from a measuring line wound on the installation rod 12 through lead ports on two sides of the sample container 1, enabling the installation rod 12 to pass through the centers of end covers at two ends to reserve round openings, screwing a thread on the end cover at one end, fixing the installation rod 12 by using a bolt, filling soil into the sample container 1, continuously vibrating in the soil filling process to ensure that a soil layer is compact, screwing a thread on the end cover at the other end, fixing the end cover and the installation rod 12 by using a bolt, and then installing a refrigeration system and a normal temperature system;
a refrigerating machine of the refrigeration system is connected with a liquid inlet 5a on a cold end cover 2 through a liquid inlet main pipe 14, a refrigerant flows back to the refrigerating machine through a liquid outlet main pipe 15 from a liquid outlet 5b, a normal-temperature water pipe 13 is connected with a variable-frequency water pump 9 through a water pipe, and water flows back to a water tank after sequentially passing through a water inlet pipe, an inlet end 13a, the normal-temperature water pipe 13 and a water outlet pipe at an outlet end 13b by the variable-frequency water pump 9 in the water tank;
(2) debugging an experimental device, starting a freezing system, setting the freezing temperature, starting a water pump 9 at the other end, and setting a constant flow;
(3) simulating frost heaving, and acquiring data once at intervals of certain data acquisition time (adjusted according to experimental data acquisition conditions) in the whole process;
(4) and (5) dismantling the experimental device and processing experimental data.
The technical scheme provided by the invention has the following beneficial effects: the frost heaving effect of the soil body in the freezing construction process can be simulated, namely the variation trend of the frost heaving pressure in the freezing process is simulated; and acquiring moisture migration parameters in the soil layer in the freezing process. The comprehensive and systematic research is carried out on the frost heaving effect caused in the freezing construction engineering, and a reference basis is provided for further popularization and application of the manual layer freezing method.
The above is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (9)
1. A frost heaving experiment device, comprising:
the rock-soil sample loading device comprises a sample container (1) for loading a rock-soil sample, wherein a cold end window and a normal temperature end window are arranged on the sample container, the cold end window is arranged opposite to the normal temperature end window, a cold end cover (2) is arranged on the cold end window, and a normal temperature end cover (3) is arranged on the normal temperature end window;
the refrigeration system comprises a refrigeration unit (4) for providing cold energy, the refrigeration unit comprises a cold energy release pipeline (5), and the cold energy release pipeline is arranged on the cold end cover and used for releasing the cold energy;
the system comprises a freezing frontal surface migration detection system, wherein the freezing frontal surface migration detection system comprises a power supply (6), the power supply comprises a positive end and a negative end, the positive end and the negative end are respectively arranged on a cold end cover and a normal temperature end cover and are used for loading positive current and negative current on rock and soil samples at a cold end window and a normal temperature end window, and an ammeter (7) is connected in series with the power supply and a voltmeter (8) is connected in parallel;
the system also comprises a normal temperature system;
the normal temperature system comprises a water pump (9) for outputting normal temperature water flow, a normal temperature water pipe is connected with a water outlet of the water pump, and the normal temperature water pipe is arranged on the normal temperature end cover;
resistivity rho of rock soil in certain area in natural state2Resistivity rho in frozen state1，ρ1≠ρ2，
From ohm's law:
U＝I·(R1+R2)
while
Deducing
In the above formula, U, I can be measured by the voltmeter and the ammeter, S is the cross-sectional area of the sample, R is0The initial total resistance of the sample when unfrozen, U, I, ρ1、ρ2Are all of the parameters which are known, and are,
l0is the full length of the sample,/1Is the length of the freezing zone, /)2Is the unfrozen zone length;
by the above formula, l can be calculated1Length change of l1Length of (2)The changes represent the migration of the freezing fronts.
2. The frost heaving experiment apparatus of claim 1, wherein,
the positive electrode end is provided with a positive electrode gasket, and the positive electrode gasket is arranged on the cold end cover or the normal temperature end cover;
the negative electrode end is provided with a negative electrode gasket, and the negative electrode gasket is arranged on the normal temperature end cover or the cold end cover.
3. The frost heaving experiment apparatus of claim 1, wherein,
the power supply is a direct current power supply.
4. The frost heaving experiment apparatus of claim 1, wherein,
the sample container is a cylindrical structure with a cross section in a regular shape.
5. The frost heaving experiment apparatus of claim 4, wherein,
the cold energy release pipeline is of a spiral coil structure and is arranged on the inner side surface of the cold end cover;
the normal temperature water pipe is of a spiral coil structure and is arranged on the inner side surface of the normal temperature end cover.
6. The frost heaving experiment apparatus according to any one of claims 1 to 5,
the system also comprises a comprehensive parameter acquisition system, wherein the comprehensive parameter acquisition system comprises a data acquisition analyzer (10);
the comprehensive parameter acquisition system further comprises a temperature information acquisition assembly for acquiring the temperature information of the rock and soil sample, and the temperature information acquisition assembly is in signal connection with the data acquisition analyzer and is arranged in the sample container.
7. The frost heaving experiment apparatus of claim 6, wherein,
the comprehensive parameter acquisition system further comprises a moisture information acquisition component for acquiring moisture information of the rock and soil sample, and the moisture information acquisition component is in signal connection with the data acquisition analyzer and is arranged in the sample container.
8. The frost heaving experiment apparatus of claim 7, wherein,
the comprehensive parameter acquisition system also comprises a stress-strain information acquisition component for acquiring the stress-strain information of the rock-soil sample, and the stress-strain information acquisition component is in signal connection with the data acquisition analyzer and is arranged in the sample container.
9. The frost heaving experiment apparatus of claim 8, wherein,
the temperature information acquisition component, the moisture information acquisition component and the stress-strain information acquisition component form a detection unit (11);
and a mounting rod (12) is arranged in the sample container from the cold end window to the normal temperature end window, and the detection unit is arranged on the mounting rod.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910490231.8A CN110108748B (en) | 2019-06-05 | 2019-06-05 | Frost heaving experimental device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910490231.8A CN110108748B (en) | 2019-06-05 | 2019-06-05 | Frost heaving experimental device |
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