Investigation of the Constitutive Modle of Saturated Frozen Soil Based on Damage

2013 ◽  
Vol 353-356 ◽  
pp. 221-224
Author(s):  
Shuang Zhang ◽  
Chun An Tang ◽  
Lei Li ◽  
Shuai Li
Keyword(s):  
Phase Transition ◽  
Temperature Field ◽  
Stress Field ◽  
Constitutive Model ◽  
Internal Structure ◽  
Damage Mechanics ◽  
Frozen Soil ◽  
Unfrozen Water ◽  
Freezing And Thawing ◽  
Water Field

Saturated frozen soil is composed of soil, unfrozen water and ice, whose subgrade deformation is due to the weakened of internal structure which coursed by damage of the materials in the process of the cycle of freezing and thawing. Considing of the heterogeneity of saturated frozen soil and the phase transition between water and ice, and using of the damage mechanics theory, thermodynamics theory, filtration mechanics theory, a constitutive model of saturated frozen soil is setted up, which is of the coupfing problem of temperature field, water field and stress field. The rationality and validity of the model is verified by the experiment. It is also provided a new method for the study of frozen soil.

Thermodynamic Properties of Water during Phase Transition and Simulation on Freezing Process in Fractured Rock

2011 ◽  
Vol 328-330 ◽  
pp. 9-12 ◽  
Author(s):  
Yong Shui Kang ◽  
Quan Sheng Liu ◽  
Jie Yan
Keyword(s):  
Phase Transition ◽  
Temperature Field ◽  
Stress Field ◽  
Thermodynamic Properties ◽  
Fractured Rock ◽  
Freezing Process ◽  
Thermodynamic Equations

Thermodynamic properties of water during phase transition in fractured rock are discussed. Thermodynamic equations of water in fractured rock while freezing were analyzed, and an example was simulated by FLAC3D. The stress field as well as the temperature field is obtained. The results demonstrated mechanical and thermal influences on rock due to phase transition of water in fractures.

Study on Elastic-Plastic Damage Constitutive Model of Frozen Soil Based on Energy Dissipation Theory

2013 ◽  
Vol 423-426 ◽  
pp. 1187-1192 ◽  
Author(s):  
Zhi Min Li ◽  
Tao Liu ◽  
Zhi Li Cui
Keyword(s):  
Energy Dissipation ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Yield Criterion ◽  
Dissipation Function ◽  
Frozen Soil ◽  
Elastic Plastic ◽  
Plastic Damage ◽  
Plastic Dissipation ◽  
Damage Constitutive Model

Starting from the thermodynamics, model of frozen soil is studied by energy dissipation theory and the inside and outside the state variables is given under isothermal conditions. Damage of frozen soil is re-flecked by effective stress and damage tensor in Damage Mechanics. Dissipation function is in form of plastic dissipation function (DP yield criterion) and the damage dissipation function. And plastic dissipation function is coupled of the damage variable. Through the elastic-plastic and damage evolution, frozen soil incremental elastic-plastic damage constitutive model is made. And finite element scheme is given.

scholarly journals A Study of Coupled Creep Damaged Constitutive Model of Artificial Frozen Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Dongwei Li ◽  
Junhao Chen ◽  
Yan Zhou
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Damage Mechanics ◽  
Yield Criterion ◽  
Creep Damage ◽  
Confining Pressure ◽  
Frozen Soil ◽  
Finite Element Program ◽  
Finite Element Software ◽  
Frozen Clay

Artificial frozen soil is a kind of typical creep material, and the frozen clay under the unloading stress paths of high-confining pressure conforms to the improved the Zienkiewicz–Pande parabola-type yield criterion, and the Mohr–Coulomb yield function can describe the shear yield surface of artificial frozen clay under low-confining pressure. Based on the results of triaxial creep and shear tests for artificial frozen soil, the viscoplastic damage variable and evolution rule of artificial frozen clay were obtained by using the theory of viscoelastic-plastic mechanics and damage mechanics. An improved Zienkiewicz–Pande parabola-type yield criterion was used instead of a linear Newton body to obtain a coupled constitutive model of viscoelastic-plastic damage in the frozen soil under the unloading stress paths and to derive the coupling flexibility matrix for viscoelastic and viscoplastic damage. A finite element program of artificial frozen soil considering creep damage was written in the Visual Fortran 6.6A environment and embedded into the nonlinear finite element software ADINA as a user subroutine. The results of numerical simulation and laboratory testing were identical, with a maximum error of no more than 4.8%. This work shows that it is reasonable to describe the creep constitutive model of frozen soil with the viscoelastic-plastic-coupled constitutive model.

scholarly journals Dynamic constitutive model of frozen soil that considers the evolution of volume fraction of ice

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Qijun Xie ◽  
Lijun Su ◽  
Zhiwu Zhu
Keyword(s):  
Constitutive Model ◽  
Volume Fraction ◽  
Frozen Soil ◽  
Unfrozen Water ◽  
Adiabatic Temperature Rise ◽  
Unfrozen Water Content ◽  
Strain Relationship ◽  
Instantaneous Temperature ◽  
Relationship Of ◽  
The Relationship

AbstractA new constitutive model for frozen soils under high strain rate is developed. By taking the frozen soil as a composite material and considering the adiabatic temperature rise and interfacial debonding damage, the nonlinear dynamic response (NDR) of the frozen soil is predicted. At the same time, the relationship between instantaneous temperature and unfrozen water content is given, and an evolution rule of the volume fraction of ice particles is obtained. This relationship shows good agreement with experimental data. Using this new constitutive model, the stress–strain relationship of frozen soil under impact loading at temperatures of − 3 °C, − 8 °C, − 18 °C, and − 28 °C is calculated. There is good agreements between the results based on this new constitutive model and the data of dynamic impact.

Progressive failure analysis of scarf-repaired composite laminate based on damage constitutive model

2016 ◽  
Vol 233 (2) ◽  
pp. 180-188 ◽  
Author(s):  
Qiuyi Shen ◽  
Zhenghao Zhu ◽  
Yi Liu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Composite Laminate ◽  
Damage Mechanics ◽  
Cohesive Zone Model ◽  
Load Capacity ◽  
Three Dimensional ◽  
Zone Model ◽  
State Variables ◽  
Element Analysis

A three-dimensional finite element model for scarf-repaired composite laminate was established on continuum damage model to predict the load capacity under tensile loading. The mixed-mode cohesive zone model was adopted to the debonding behavior analysis of adhesive. Damage condition and failure of laminates and adhesive were subsequently addressed. A three-dimensional bilinear constitutive model was developed for composite materials based on damage mechanics and applied to damage evolution and loading capacity analyses by quantifying damage level through damage state variables. The numerical analyses were implemented with ABAQUS finite element analysis by coding the constitutive model into material subroutine VUMAT. Good agreement between the numerical and experimental results shows the accuracy and adaptability of the model.

Geothermal modeling of soil or mine tailings with concurrent freezing and deposition

1998 ◽  
Vol 35 (2) ◽  
pp. 234-250 ◽  
Author(s):  
JF (Derick) Nixon ◽  
Nick Holl
Keyword(s):  
Snow Cover ◽  
Mine Tailings ◽  
Frozen Soil ◽  
Freezing And Thawing ◽  
Frozen Ground ◽  
Geothermal Model ◽  
Winter Time ◽  
Upper Boundary ◽  
Good Agreement

A geothermal model is described that simulates simultaneous deposition, freezing, and thawing of mine tailings or sequentially placed layers of embankment soil. When layers of soil or mine tailings are placed during winter subfreezing conditions, frozen layers are formed in the soil profile that may persist with time. The following summer, warmer soil placement may not be sufficient to thaw out layers from the preceding winter. Remnant frozen soil layers may persist for many years or decades. The analysis is unique, as it involves a moving upper boundary and different surface snow cover functions applied in winter time. The model is calibrated based on two uranium mines in northern Saskatchewan. The Rabbit Lake scenario involves tailings growth to a height of 120 m over a period of 24 years. At Key Lake, tailings increase in height at a rate of 1.3 m/year. Good agreement between the observed position of frozen layers and those predicted by the model is obtained. Long-term predictions indicate that from 80 to 200 years would be required to thaw out the frozen layers formed during placement, assuming 1992 placement conditions continue. Deposition rates of 1.5-3 m/year give the largest amounts of frozen ground. The amount of frozen ground is sensitive to the assumed snow cover function during winter.Key words: geothermal, model, tailings, freezing, deposition.

scholarly journals A simple model for predicting soil temperature in snow-covered and seasonally frozen soil: model description and testing

2004 ◽  
Vol 8 (4) ◽  
pp. 706-716 ◽  
Author(s):  
K. Rankinen ◽  
T. Karvonen ◽  
D. Butterfield
Keyword(s):  
Heat Capacity ◽  
Simple Model ◽  
Soil Temperature ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Frozen Soil ◽  
Model Description ◽  
Freezing And Thawing ◽  
Catchment Scale ◽  
Soil Temperatures

Abstract. Microbial processes in soil are moisture, nutrient and temperature dependent and, consequently, accurate calculation of soil temperature is important for modelling nitrogen processes. Microbial activity in soil occurs even at sub-zero temperatures so that, in northern latitudes, a method to calculate soil temperature under snow cover and in frozen soils is required. This paper describes a new and simple model to calculate daily values for soil temperature at various depths in both frozen and unfrozen soils. The model requires four parameters: average soil thermal conductivity, specific heat capacity of soil, specific heat capacity due to freezing and thawing and an empirical snow parameter. Precipitation, air temperature and snow depth (measured or calculated) are needed as input variables. The proposed model was applied to five sites in different parts of Finland representing different climates and soil types. Observed soil temperatures at depths of 20 and 50 cm (September 1981–August 1990) were used for model calibration. The calibrated model was then tested using observed soil temperatures from September 1990 to August 2001. R2-values of the calibration period varied between 0.87 and 0.96 at a depth of 20 cm and between 0.78 and 0.97 at 50 cm. R2-values of the testing period were between 0.87 and 0.94 at a depth of 20cm, and between 0.80 and 0.98 at 50cm. Thus, despite the simplifications made, the model was able to simulate soil temperature at these study sites. This simple model simulates soil temperature well in the uppermost soil layers where most of the nitrogen processes occur. The small number of parameters required means that the model is suitable for addition to catchment scale models. Keywords: soil temperature, snow model

Heat Effect Analysis of Buried Oil Pipeline in the Qinghai-Tibet Plateau

2014 ◽  
Vol 501-504 ◽  
pp. 211-217
Author(s):  
Wei Bo Liu ◽  
Wen Bing Yu ◽  
Xin Yi ◽  
Lin Chen
Keyword(s):  
Temperature Field ◽  
Frozen Soil ◽  
Operating Conditions ◽  
Tibet Plateau ◽  
Soil Mechanic ◽  
Insulation Layer ◽  
Effect Analysis ◽  
Oil Pipeline ◽  
Permafrost Table ◽  
Qinghai Tibet Plateau

The Geermu-Lasa oil pipeline was located in the Qinghai-Tibet Plateau permafrost regions. The building and operating of pipeline will change the temperature field of soil around it, which can lead to changes of frozen soil mechanic properties, and this will induces deformation or even fracture of pipeline. These phenomena will affect the normal transportation of oil. In this paper, temperature field around the pipelines were analyzed due to different pipe diameters and different insulation layer thicknesses in the way of finite element method. The rule of thawing and freezing of soil around the pipeline in an annual cycle was obtained. Artificial permafrost table variations under the pipeline were also obtained due to different operating conditions. For 30cm diameter pipeline with 7cm insulation layer, its artificial permafrost table depth change value is just 0.48m after 30-year running. These analysis results can provide references to the construction of the new Geermu-Lasa oil pipeline.

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