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165 results about "Freeze thaw cycling" patented technology

Freeze-thaw cycling is an important processing step in the preparation of liposomes that leads to the encapsulation of drug molecules. There is considerable variability in the number of freeze-thaw cycles reported in the literature.

Cryopreservation of human red blood cells

A red blood cell storage composition includes a composition of red blood cells and biochemistry altering reagents, the biochemistry altering reagents being present at a concentration so as to reduce the percent hemolysis of the red blood cells during the freeze-thaw cycle below that of the percent hemolysis of the red blood cells in the absence the biochemistry altering reagents. The red blood cell storage composition preferably includes reagents selected from: modifiers of glycolytic / metabolic components, modifiers of antioxidant potential, effectors of intracellular ionic distribution, modifiers of membrane fluidity, modifiers of cytoskeletal structure, effectors of the cyclooxygenase second messenger pathway, effectors of the lipoxygenase second messenger pathway, effectors of the hexose monophosphate second messenger pathway, effectors of the phosphorylation second messenger pathway, modifiers of specific messenger molecules, and combinations thereof.
Owner:LIFECELL

Low-temperature type wood-plastic floor and preparation technology thereof

The invention discloses a low-temperature type wood-plastic floor and a preparation technology thereof. The floor comprises substances of: plastic particles, plant fiber, a filling material, a compatibilizer, a lubricant, a pigment, and functional auxiliary agents. Compared with existing technologies, according to the invention, melted and modified plastic particles are adopted, the components are well formulated, and the mold of the product is improved. Under a temperature of -34 DEG C to 60 DEG C, the linear expansion coefficient of the prepared product is smaller than 5*10<-5>. When the product is processed through three times of freeze-thaw cycling tests according to ASTM D6109-10, the bending strength retention of the product is more than 97%.
Owner:HUANGSHAN HUASU NEW MATERIAL SCI & TECH CO LTD

Method and apparatus for stimulating production from oil and gas wells by freeze-thaw cycling

In a well stimulation method, a subsurface formation is fractured by freezing a water-containing zone within the formation in the vicinity of a well, thereby generating expansive pressures which expand or created cracks and fissures in the formation. The frozen zone is then allowed to thaw. This freeze-thaw process causes rock particles in existing cracks and fissures to become dislodged and reoriented therewithin, and also causes new or additional rock particles to become disposed within both existing and newly-formed cracks and fissures. The particles present in the cracks and fissures act as natural proppants to help keep the cracks and fissures open, thereby facilitating the flow of fluids from the formation into the well after the formation has thawed. Preferably, the freeze-thaw steps are carried out on a cyclic basis. Optionally, propagation of the freezing front into the formation may be enhanced by the introduction of low-frequency wave energy into the formation.
Owner:POLAR WELL STIMULATIONS LTD

Load and freeze-thaw cycle coupled concrete durability testing device and evaluation method

The invention discloses a load and freeze-thaw cycle coupled concrete durability testing device and an evaluation method. The device comprises a concrete load and freeze-thaw cycle coupling device, aconcrete strain testing system and a freeze-thaw testing machine. The concrete load and freeze-thaw cycle coupling device is placed in the freeze-thaw testing machine for a freeze-thaw cycle couplingtest. Sample strain data is recorded at real time through the concrete strain testing system, and by testing parameters such as rate of strain change, rate of mass change, etc. of a test piece after acertain times of load and freeze-thaw cycle coupling, durability of the concrete is evaluated. According to the invention, durability of loaded concrete (member) serving in severe cold areas can be rapidly tested, and load and freeze-thaw cycle coupling effect in actual service is accurately simulated. The method is simple to operate and is scientific and effective. The invention provides technical support for durability design and material selection of large-scale engineering structures under complex service conditions such as severe cold condition, etc.
Owner:CENT SOUTH UNIV +1

Device for testing hydrothermal variation features of hydrous porous medium in freeze thawing process

The invention relates to a device for testing hydrothermal variation features of a hydrous porous medium in a freeze thawing process. The device is characterized in that a double-layer system of internal and external model boxes is adopted, a test sample and a variety of sensors are arranged in the internal model box, the external model box mainly plays a heat preservation and thermal insulation role, refrigerating coils arranged on the inner side wall and at the bottom of the external model box are communicated with two external cold baths to control the temperature and integrally heat and cool, and such liquid with low freezing points as alcohol, kerosene and ethanediol can be placed in the interlayer space of the internal and external model boxes to improve the temperature control precision and the constant temperature effect. The device provided by the invention is mainly used for testing the hydrothermal variation feature parameters of the hydrous porous medium in the freeze thawing process, comprising temperature, volume unfrozen water content, matric suction and the like, so that a water feature curve of the hydrous porous medium in the freeze thawing process is drawn. The device provided by the invention has the advantages of simplicity in operation, stable work, high temperature control precision, high overall heating and cooling speed and the like, data are automatically collected by a data collector, and then the hydrothermal variation feature parameters of the hydrous porous medium in the freeze thawing process are effectively tested and the water feature curve is accurately obtained.
Owner:NORTHWEST INST OF ECO ENVIRONMENT & RESOURCES CAS

Cement-based polymers anti-corrosive paint and method for preparing same

ActiveCN101333403APreserve anti-agingKeep fireproofAnti-corrosive paintsEpoxy resin coatingsEpoxyCellulose
The invention discloses polymer cement antiseptic paint and a preparation method thereof which includes the steps of respectively mixing solidoid materials and liquidoid materials to be even, gradually adding the solidoid materials into the liquidoid materials, and blending thoroughly until no bladders exist; wherein the liquidoid materials include 10-50wt% of epoxy emulsion, 0-30wt% of vinyl acetate-ethene copolymer emulsion, 0-30wt% of cinnamene-acrylate copolymer emulsion, 0-1wt% of organosilicon defoamer and 2-10wt% of polyene polyamine hardener; the solidoid materials include 20-39wt% of cement, 8-19wt% of quartz sand and 0-2wt% of cellulose. The polymer cement antiseptic paint has high strength, high bending resistance, high viscosity, corrosion resistance and aging resistance and is flameproof, nontoxic and safe to use during construction; therefore the polymer cement antiseptic paint is ideal material for the sections or parts that are high in concentration of sulfate, moisture evaporation, freeze-thaw cycling, dry-wet alternation or hydraulic scour and are exposed to sulfate corrosion.
Owner:CHINA BUILDING MATERIALS ACAD

Preparation method of hemostatic sponge and hemostatic sponge prepared thereby

The invention discloses a preparation method of a hemostatic sponge, comprising the following steps: (1) dispersing oxidized cellulose powder into water to obtain 0.1-2.0wt% of oxidized cellulose dispersion, and then homogenizing the oxidized cellulose dispersion under high pressure to obtain a nanooxidized cellulose suspension; (2) injecting the nanooxidized cellulose suspension into a mold, performing 1 to 7 times of freeze-thaw cycles to obtain nanocellulose hydrogel, freezing the nanocellulose hydrogel for sizing, and then drying to obtain the hemostatic sponge; wherein one freeze-thaw process is: freezing for 8-16 h at -40 to -18 DEG C, and then unfreezing for 8-16 h at 4-25 DEG C. The invention also provides the hemostatic sponge prepared by the preparation method. The hemostatic sponge has high carboxyl content, high porosity and water absorption capacity, and can quickly absorb excess blood on the wound surface to achieve effective hemostasis.
Owner:ZHENGZHOU UNIV

Real-time monitoring system and method for frost heaving deformation expansion of rock ice-containing cracks

The invention discloses a real-time monitoring system and method for frost heaving deformation expansion of rock ice-containing cracks. The real-time monitoring system for frost heaving deformation expansion of rock ice-containing cracks comprises a CT scanning system, a rock freezing and thawing system, a crack deformation measuring system and a frost heaving force measuring system. The CT scanning system comprises a vertical rack, an area array detector, an X-ray transmitter, a rotating system and a base. The rock freezing and thawing system comprises a water storage barrel, a freezing barrel and a freezing circulation system, the water storage barrel is located above the freezing barrel, a rock sample is placed in the freezing barrel, the freezing barrel is installed on the rotating system, and the freezing circulation system is connected with the freezing barrel; the fracture deformation measuring system and the frost heaving force measuring system are connected with the rock sample and are respectively used for measuring the deformation condition and the frost heaving force change condition of the rock sample in the freezing process; according to the invention, frost heaving deformation of rock fractures can be measured, and the expansion evolution mesoscopic process of rock ice-containing fractures under the action of freeze-thaw cycle can be observed in real time.
Owner:UNIV OF SCI & TECH BEIJING

Compositions and methods to prevent AAV vector aggregation

Compositions and methods are provided for preparation of concentrated stock solutions of AAV virions without aggregation. Formulations for AAV preparation and storage are high ionic strength solutions (e.g. mu~500mM) that are nonetheless isotonic with the intended target tissue. This combination of high ionic strength and modest osmolarity is achieved using salts of high valency, such as sodium citrate. AAV stock solutions up to 6.4x10<13> vg / mL are possible using the formulations of the invention, with no aggregation being observed even after ten freeze-thaw cycles. The surfactant Pluronic(R) F68 may be added at 0.001% to prevent losses of virions to surfaces during handling. Virion preparations can also be treated with nucleases to eliminate small nucleic acid strands on virions surfaces that exacerbate aggregation.
Owner:GENZYME CORP

Prediction method for long-term deformation of freeze-thaw damaged soft rock

The invention discloses a prediction method for long-term deformation of freeze-thaw damaged soft rock, provides a dangerous rock body deformation judgment criterion for geotechnical engineering construction in a cold region, and guarantees the safety of foundation engineering in whole life cycle use. The method comprises the following steps: (1) constructing a freeze-thaw aging damage variable multivariate function; (2) constructing a freeze-thaw aging damage coupling creep mechanics constitutive equation in combination with a freeze-thaw aging damage variable multivariate function; (3) performing standard regulation sampling on the on-site soft rock, and recording the change value of the strain of the rock sample along with the stress and time; (4) carrying out nonlinear fitting on the strain time curve and the constitutive equation to determine each mechanical parameter in the equation; (5), converting the rock mechanics parameters into rock mechanics parameters; (6) determining equivalent freeze-thaw cycle times through an indoor and outdoor freeze-thaw cycle equivalent equation; (7) actually measuring the spatial distribution rule and displacement increment of a rock mass stress field on site; and (8) predicting a strain value corresponding to the rock mass at a future tf moment.
Owner:CHINA RAILWAY ERYUAN ENG GRP CO LTD

Nondestructive prediction combination method for evaluating rock uniaxial compressive strength under freeze-thaw cycle

The invention relates to a nondestructive prediction combination method for evaluating rock uniaxial compressive strength under freeze-thaw cycle. The nondestructive prediction combination method comprises the following steps: preparing a plurality of standard rock samples from a complete rock block of a rock to be tested; continuously and repeatedly carrying out freeze-thaw circulation on the plurality of standard rock samples until the standard rock samples are damaged; in the repeated freeze-thaw cycle process, after five freeze-thaw cycles are completed each time, performing a measurementprocess, and according to the mass, the longitudinal wave velocity and the porosity, calculating the limit uniaxial compressive strength of the rock to be measured by using a uniaxial compressive strength formula. According to the nondestructive prediction combination method, the porosity of the rock and the trend of the internal fracture are jointly determined through the ultrasonic technology and the nuclear magnetic resonance technology, the macroscopic integrity of the rock is controlled through the weight, the microcosmic and macroscopic structures of the rock are controlled, and prediction of the uniaxial compressive strength of the rock is more accurate.
Owner:INST OF ROCK AND SOIL MECHANICS - CHINESE ACAD OF SCI

Method and compositions for polymer nanocarriers containing therapeutic molecules

A method of controlling a physical characteristic of polymeric nanocarrier-encapsulated protein particles includes altering or selecting a weight percentage of a hydrophobic polymer block in a total amphiphilic diblock copolymer of a primary emulsion of a double emulsion, freeze-thaw technique. The primary emulsion is formed using a freeze-thaw cycle of the amphiphilic diblock copolymer and a protein having a molecular weight of up to or equal to 300,000 Da. Selection of the hydrophobic polymer block percentage alters one or more characteristics of the resulting nanoparticles, such as shape. Thus, as one aspect, a method of producing filamentous polymeric nanocarrier-encapsulated protein (i.e., active enzyme) particles involves forming a primary emulsion using a freeze-thaw cycle of (i) an amphiphilic diblock copolymer, which has a molecular weight of about 10,000 to about 100,000 Da and comprises a conjugate of the hydrophobic polymer block and a hydrophilic polymer block, wherein the amphiphilic diblock copolymer comprises greater than 81% to about 95% by weight of the hydrophobic polymer block; and a protein having a molecular weight of up to or equal to about 300,000 Da. Various compositions comprising such filamentous-shaped nanocarrier particles, and methods of use for diagnosis and therapy are disclosed.
Owner:THE TRUSTEES OF THE UNIV OF PENNSYLVANIA

High-strength polyvinyl alcohol gel and preparation method and application thereof

The invention relates to a high-strength polyvinyl alcohol gel and a preparation method and application thereof. The method for preparing the high-strength polyvinyl alcohol gel comprises the following steps: a) carrying out a crosslinking reaction of a polyvinyl alcohol aqueous solution in the presence of a crosslinking agent and a catalyst to obtain a polyvinyl alcohol primary gel; and b) performing repeated freezing and thawing treatment on the polyvinyl alcohol primary gel to obtain the polyvinyl alcohol gel, wherein the crosslinking agent is selected from multiple epoxy compounds, and a mass ratio of the crosslinking agent to polyvinyl alcohol in the polyvinyl alcohol aqueous solution is 0.001-5:1. The multiple epoxy compounds are used to carry out chemical crosslinking, biosafety ofthe polyvinyl alcohol gel is guaranteed, and strong guarantees for flexibility and stability of the polyvinyl alcohol gel are provided. Combination of chemical crosslinking and freeze-thaw cycle physical crosslinking gives the polyvinyl alcohol gel better mechanical properties, and better strength, flexibility and stability, and application needs of the polyvinyl alcohol gel in the artificial cartilage or soft tissue aspect is more conducive to meet.
Owner:IMEIK TECH DEV CO LTD

Freeze-thaw resistant recycled concrete and preparation method thereof

The invention discloses freeze-thaw resistant recycled concrete and a preparation method thereof. The concrete is prepared from the following raw materials: Portland cement, fine aggregate, coarse aggregate, water, a water reducing agent, an air entraining agent and rubber powder; the fine aggregate comprises organic silicon resin modified recycled fine aggregate, and the coarse aggregate comprises organic silicon resin modified recycled coarse aggregate. The rubber powder and the air entraining agent provide an expansion space for free water expansion in the recycled concrete, the expansion stress in the recycled concrete is reduced, meanwhile, the surface of the recycled aggregate is coated with the organic silicon resin, the water absorption of the recycled aggregate is reduced, and the freeze-thaw resistance of the recycled concrete is improved; and the modified recycled aggregate is tightly connected with a cement gel system, so the interior of the recycled concrete is compact, and the compressive strength of the recycled concrete is enhanced.
Owner:崇德建材集团有限公司

Method for determining freezing-thawing damage degree of rock in high-altitude cold region

The invention discloses a method for determining freezing-thawing damage degree of a rock in a high-altitude cold region. The method comprises the following steps: selecting a high-altitude cold region rock sample, drying the sample to a constant weight, cooling the sample, and saturating the sample with water; performing freeze-thaw cycle treatment on the water-saturated sample, measuring the gaspermeability of the sample under the same confining pressure under the same osmotic pressure after different freeze-thaw cycles, drawing a change curve of the gas permeability of the rock with different freeze-thaw cycles, and fitting the curve; defining a calculation formula of a freezing-thawing damage quantity D: D = 1 - (ki / k0),wherein k0 is the gas permeability of the sample before freezingand thawing, ki is the gas permeability of the sample after i freezing-thawing cycles, and i=1, 2, 3, 4...; and drawing a change curve of the freezing-thawing damage quantity of the rock with the number of freezing-thawing cycles, fitting the curve by a function, and determining the according to the degree of rock damages caused by any freezing-thawing cycle according to the fitting function. Themethod defines the freezing-thawing damage quantity of the rock by the gas permeability of the rock, and makes a test result accurate, scientific and reliable.
Owner:HOHAI UNIV

Unsaturated roadbed soil freeze-thaw cycle model test system

The invention discloses an unsaturated roadbed soil freeze-thaw cycle model test system, relates to a freeze-thaw cycle test device, and aims to solve the problem that an existing freeze-thaw cycle test device cannot truly and accurately reflect the comprehensive influence of temperature, moisture and load in the actual freeze-thaw cycle process, wherein the device comprises a test bin, a controlsystem and a data acquisition system, and the test bin comprises a sleeve, a heat preservation body and a water permeable part; a test piece is loaded in the sleeve, the side wall is hermetically wrapped with a thermal insulator, and the water permeable part is arranged at the bottom; the control system comprises a temperature control system, a moisture control system and a load control system; the temperature control system comprises a temperature control chamber, an upper temperature control disc and a lower temperature control disc; the temperature control chamber covers the test bin; the upper temperature control disc and the lower temperature control disc are respectively arranged at the top and the bottom of the sleeve; the moisture control system is communicated with the bottom of the test piece through a water supplementing pipe; the load control system is arranged at the top of the sleeve; the data acquisition system comprises a temperature acquisition system, a moisture acquisition system and a displacement acquisition system.
Owner:HARBIN INST OF TECH

Concrete composite air entraining agent, its preparation and use methods

Belonging to the technical field of building materials, the invention discloses a concrete composite air entraining agent, its preparation and use methods. The composite air entraining agent is composed of sodium dodecyl sulfate (14-60%), beta-cyclodextrin (30-84%), Arabic gum (1-8%), and bone gum (1-10%). The component raw materials are stirred evenly by physical and mechanical mixing, thus obtaining the concrete composite air entraining agent. During use, the dosage of the air entraining agent accounts for 0.004%-0.03% of the weight of cement in concrete. The concrete composite air entraining agent provided by the invention has the advantages of wide raw material sources, simple production method and excellent product performance, can introduce a lot of small, uniform and stable bubbles into concrete, enhances the water-retaining property of green concrete, improves workability, reduces slump loss, also greatly improves the freeze-thaw cycling resistance, salt-freezing resistance and other durability indicators of concrete, and has small negative influence on the strength of a hardened body. The concrete composite air entraining agent provided by the invention can be used in reinforced concrete, lightweight aggregate concrete, artificial aggregate concrete, bridges, buildings, hydraulic engineerings, pavements and other structures.
Owner:TONGJI UNIV

Rock damage acoustic monitoring device and method in freeze-thaw dry and wet environment

The invention provides a rock damage acoustic monitoring device and method in a freeze-thaw dry and wet environment, and relates to the technical field of rock engineering. The rock damage acoustic monitoring device in the freeze-thaw dry and wet environment comprises a sample tank, a dry-wet circulating system which is used for supplying water to the top of the rock sample placed in the sample tank; a freeze-thaw circulating system which is used for adjusting the temperature of the rock sample placed in the sample tank; and an acoustic wave emission probe which is used for acquiring damage information of the rock sample. The dry-wet circulating system can simulate a rainfall environment by supplying water to the top of a rock sample, and the freeze-thaw circulating system simulates the freeze-thaw state of the rock so as to simulate the frost heaving inoculation evolution process of the rock mass in the cold region. The acoustic wave emission probe receives ultrasonic waves and sound emission signals and monitors the development, communication and damage process of the freeze-thaw cycle rock mass microfractures. The device can accurately monitor the space-time evolution process of the microscopic damage of the rock sample in the freeze-thaw dry and wet environment, and reveals the performance degradation mechanism of the rock mass in the complex environment.
Owner:NORTHWEST INST OF ECO-ENVIRONMENT & RESOURCES CAS

Method for obtaining unfrozen water content in rocks under freeze-thaw cycle conditions

The invention belongs to the technical field of thawing rocks, and discloses a method for obtaining unfrozen water content in rocks under freeze-thaw cycle conditions, and the method comprises the following steps of preparing rock column samples, and saturating the rock column samples with formation water; performing a nuclear magnetic resonance test on the rock column samples of saturated formation water to obtain a T2 spectrum curve; converting the T2 spectrum curve into a nuclear magnetic pore throat distribution curve f(r); bringing the nuclear magnetic pore throat distribution curve f(r)into an integral formula to respectively obtain the relationship curve between unfrozen water content and temperature during melting and freezing. The method for obtaining the unfrozen water content in rocks under the freeze-thaw cycle conditions provided by the invention can achieve high accuracy and high reliability, and is easy to obtain the unfrozen water content.
Owner:INST OF ROCK AND SOIL MECHANICS - CHINESE ACAD OF SCI

Method and Compositions for Polymer Nanocarriers Containing Therapeutic Molecules

A method of controlling a physical characteristic of polymeric nanocarrier-encapsulated protein particles includes altering or selecting a weight percentage of a hydrophobic polymer block in a total amphiphilic diblock copolymer of a primary emulsion of a double emulsion, freeze-thaw technique. The primary emulsion is formed using a freeze-thaw cycle of the amphiphilic diblock copolymer and a protein having a molecular weight of up to or equal to 300,000 Da. Selection of the hydrophobic polymer block percentage alters one or more characteristics of the resulting nanoparticles, such as shape. Thus, as one aspect, a method of producing filamentous polymeric nanocarrier-encapsulated protein (i.e., active enzyme) particles involves forming a primary emulsion using a freeze-thaw cycle of (i) an amphiphilic diblock copolymer, which has a molecular weight of about 10,000 to about 100,000 Da and comprises a conjugate of the hydrophobic polymer block and a hydrophilic polymer block, wherein the amphiphilic diblock copolymer comprises greater than 81% to about 95% by weight of the hydrophobic polymer block; and a protein having a molecular weight of up to or equal to about 300,000 Da. Various compositions comprising such filamentous-shaped nanocarrier particles, and methods of use for diagnosis and therapy are disclosed.
Owner:THE TRUSTEES OF THE UNIV OF PENNSYLVANIA

Three-sample linkage freeze-thaw test system for real-time simulation of freeze-thaw process of soil

InactiveCN108398453AMonitor temperature in real timeReal-time monitoring of freeze-thaw subsidenceMaterial thermal analysisFreeze thawingDynamic balance
The invention relates to a three-sample linkage freeze-thaw test system for the real-time simulation of freeze-thaw process of soil. A test box body is composed of a working chamber, a refrigeration unit, an air conditioning air supply device, a control system and a safety protection system; a water supply system monitors and observes the change of water and the state of the pore water pressure inreal time in the freeze-thaw process of a sample; a cold source circulation tank system adopts an integrated structure formed by a drawer type layout in a cold bath tank; a refrigeration system adopts a high-precision temperature and humidity control system, so the refrigeration system is effectively and safely protected; the air conditioning system control system automatically achieves dynamic balance and achieves the purpose of temperature change; an electrical measurement and control system ensures the automatic degree of the system, and important parameters in the test process are displayed by a human-computer interaction interface; and the safety protection system protects the safe running of the system in real time. The three-sample linkage freeze-thaw test system has the characteristics of real time, high efficiency, safety, stability, automation, convenient energy saving, simple simulation process, good stability and reliability, and high precision.
Owner:COLD & ARID REGIONS ENVIRONMENTAL & ENG RES INST CHINESE

Automatic dry-wet freeze-thaw cycling test device and test method

The invention discloses an automatic dry-wet freeze-thaw cycling test device which comprises an operation platform, a control module, an evaporation module, a spray module, a weighing module, a refrigeration module and a manipulator operation module, wherein the spray module controls a peristaltic pump through a pulse control sent by the control module to complete the control on the water additionamount; the weighing module detects the quality through a pressure sensor and completes the quality control and data collection; the refrigeration module adopts a refrigeration box; and the manipulator operation module controls a stepping motor to realize the walk in any position in a two-dimensional space through the control module. The invention also discloses an automatic dry-wet freeze-thaw cycling test method. According to the test method, a signal is sent to the control module according to an input parameter instruction, and the whole process of a wet-dry freeze-thaw cycling test is completed through cooperation of each module. The test device and the test method provided by the invention are professionally used for the dry-wet freeze-thaw cycling test of loess, thereby realizing the fully-automatic control of the test, improving the test precision, reducing the personnel investment and lowering the production cost.
Owner:甘肃省公路交通建设集团有限公司 +1

Compositions and kits for omeprazole suspension

Disclosed herein are liquid diluents, formulations, and kits for preparing reconstituted suspensions of a proton pump inhibitor (e.g., omeprazole). The present disclosure also provides formulations for liquid diluents that do not have a tendency for gel formation following exposure to freeze-thaw cycles.
Owner:AZURITY PHARMA INC

Rock-soil body freeze thawing-stress coupling creep test instrument and test method in water environment

The invention discloses a rock-soil body freeze-thaw stress coupling creep test instrument and test method in a water environment. The test instrument comprises a hydraulic control system, a water pressure control system, a freeze-thaw circulating system, a temperature control system and a data acquisition system. A rock-soil body sample is placed in a pressure-bearing barrel of the triaxial creeptest device, confining pressure is applied to the rock-soil body sample through a water pressure control system, axial pressure is applied to the rock-soil body sample through a hydraulic control system, a freeze-thaw cycle system provides freeze-thaw cycle working conditions for the test through a refrigerating machine and a heating machine, and a temperature control system monitors and controlsthe temperature in the pressure-bearing barrel; after the axial pressure and the water pressure are stable, a rock-soil body sample triaxial creep test is carried out, and a data acquisition system acquires test data in the test process in real time. The invention also provides a rock-soil body freeze-thaw stress coupling creep test method in a water environment. According to the invention, the triaxial creep test of the rock-soil body is carried out in a freeze-thaw cycle environment, and the efficiency and precision of the test are effectively improved.
Owner:SICHUAN UNIV

Test device for simulating dry-wet cycle and freeze-thaw cycle of roadbed soil body

The invention discloses a test device for simulating a dry-wet cycle and a freeze-thaw cycle of a roadbed soil body. The test device comprises a test cylinder main body, a temperature and humidity sensor is hermetically arranged in the test cylinder main body along each detection channel in a penetrating manner, and the temperature and humidity sensor is electrically connected with the input end of a data acquisition instrument, a channel filtering piece is fixed in the outer discharging channel, and a hydraulic jack is fixed to the bottom face of a beam of the portal frame. The device has theadvantages that the hydraulic jack compacts a soil sample in the test cylinder main body, when the dry-wet cycle test is carried out, the low-temperature constant-temperature tank dries the soil sample, the low-temperature constant-temperature tank is removed, water is injected into the temperature control layer, and the dry-wet cycle test is repeatedly carried out to complete the dry-wet cycle test, when a freezing and thawing cycle test is carried out, the low-temperature constant-temperature tank repeatedly circulates the soil sample to carry out cooling freezing and heating thawing, in the dry-wet cycle and freeze-thaw cycle test process, the data monitored by the temperature and humidity sensor is fed back to the data acquisition instrument in real time, and the device is simple to operate, time-saving, labor-saving and low in investment cost.
Owner:INNER MONGOLIA UNIVERSITY

Method for determining joint shear strength considering freeze-thaw cycle damage

ActiveCN110987662AAccurate calculation of shear strengthImprove fitMaterial strength using steady shearing forcesFreeze thawingEngineering
The invention discloses a method for determining joint shear strength considering freeze-thaw cycle damage. Aiming at the complexity of rock mass joints in cold regions, the method provided by the invention deeply analyzes the relationship between the joint connectivity and the shear strength, and proposes a calculation formula of shear strength parameters changing along with the joint connectivity based on an indoor test, so that the shear strength of the complex joints can be conveniently and accurately calculated. According to the method, based on a freeze-thaw test and a direct shear testof a joint sample, a shear strength parameter damage evolution model is established; further an improved shear strength calculation formula is derived; according to the calculation formula, the damageaccumulation of freeze-thaw cycle and the influence of joint connectivity are considered at the same time; the degradation characteristics of the coupling effect of the freeze-thaw cycle and the joint connectivity on the shear strength parameters can be deeply analyzed, the high coincidence degree of the calculation result of the improved calculation formula and experimental data is obtained according to the subsequent test result, and the reasonability of the improvement criterion is shown.
Owner:CENT SOUTH UNIV

Device for simulating freezing and thawing cycle process of frozen soil

InactiveCN113447639ASolve the problem that multiple simulation experiments cannot be performed at the same timeEarth material testingMaterial thermal analysisWater storageThermodynamics
The invention discloses a device for simulating the freezing and thawing cycle process of frozen soil. The device comprises a transparent container, an upper cold bath disc, a lower cold bath disc, a water and soil partition plate, a cavity partition plate and a cold bath tank, the upper cold bath disc covers the top of the transparent container; the lower cold bath disc covers the bottom of the transparent container; the water and soil partition plate is arranged in the transparent container and detachably arranged on the lower cold bath disc, and a water storage cavity is formed between the water and soil partition plate and the lower cold bath disc; the cavity partition plate is arranged in the transparent container, is detachably connected with the transparent container, and is used for vertically separating the interior of the transparent container into a plurality of experiment cavities; the cold bath tank is connected and communicated with the upper cold bath disc and the lower cold bath disc, and the cold bath tank is used for regulating and controlling the temperature change of the upper cold bath disc and the lower cold bath disc in the experiment process; and therefore, during application, different soil bodies can be put into different experiment cavities, so that synchronous experiment comparison is carried out, and the problem that multiple simulation experiments cannot be carried out simultaneously in the prior art is practically solved.
Owner:SUN YAT SEN UNIV
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