Study on the Frost Heave Characteristics of Artificial Frozen Soil Under Different Freezing Mode

2012 ◽  
Vol 204-208 ◽  
pp. 599-603
Author(s):  
Jun Hao Chen
Keyword(s):  
Structural Design ◽  
Computer Control ◽  
Frozen Soil ◽  
The Self ◽  
Frost Heave ◽  
Test Machine ◽  
Freezing Method ◽  
Artificial Freezing ◽  
Similarities And Differences ◽  
Artificial Freezing Method

At the self-developed DZL-001 computer control of frozen soil frozen-heave test machine, use artificial freezing method carry out vertical and lateral freezing two modes frost heave test of remoulded clay, each mode test includes under no replenishment and replenishment conditions. Monitor the temperature, moisture and frost heave of frozen soil at different location. Compare the similarities and differences of frost heave characteristics of two modes, master the frost heave characteristics of artificial frozen soil. The results provide a certain guidance and reference meaning to layer sidewall structural design.

Properties of Frozen Soils for Cross Passage Construction in Line 1 and 2 of Wuxi Metro

2013 ◽  
Vol 353-356 ◽  
pp. 1662-1665 ◽  
Author(s):  
Xiang Dong Hu ◽  
Yan Guang Han
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Freezing Point ◽  
Frozen Soil ◽  
Frost Heave ◽  
Soil Test ◽  
Frozen Soils ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

Artificial ground freezing method (AGF) was applied in cross passage constructing of line 1 and 2 of Wuxi Metro. Mechanical properties of frozen soils such as uniaxial compressive strength, modulus of elasticity, Poissons Ratio, frost heave rate and freezing point are prerequisite for design and construction of AGF. In order to obtain the parameters mentioned, laboratory tests were conducted. One was the basic geotechnical test. Another was the frozen soil test.

scholarly journals Factor’s Influence Analysis of Frost Heave during the Twin-Tunnel Construction Using Artificial Horizontal Ground Freezing Method

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Rong-bao Hong ◽  
Hai-bing Cai ◽  
Meng-kai Li ◽  
Ya-ru Li
Keyword(s):  
Ground Surface ◽  
Frozen Soil ◽  
Frost Heave ◽  
Tunnel Construction ◽  
Displacement Curve ◽  
Finite Element Program ◽  
Freezing Method ◽  
Twin Tunnel ◽  
Ground Freezing ◽  
Clear Distance

In order to analyze the influence of different twin-tunnel parameters on the frost heave of the ground, six tunnel clear distances (0.25 D, 1.00 D, 1.50 D, 2.00 D, 2.50 D, and 3.00 d), three tunnel buried depths (6 m, 12 m, and 18 m), and two freezing orders (simultaneous freezing and sequential freezing) are selected to establish the two-dimensional numerical calculation models, using ABAQUS finite-element program and the user subroutine of frost heaving deformation, and considering the orthotropic deformation characteristics of frozen soil. Numerical simulation results show that the interaction of twin-tunnel freezing is weakened with the increase in tunnel clear distance. Correspondingly, the heaving displacement of the ground surface also decreases. Besides, the heaving displacement curve of the ground surface gradually changes from the unimodal N-type to bimodal M-type as the tunnel clear distance increases. However, the trough of the bimodal M-type curve gradually disappears as the tunnel buried depth increases. SPSS mathematical analysis results show that tunnel clear distance has the highest significance, tunnel buried depth ranks the second, and freezing order ranks the last. It is important to select the appropriate tunnel clear distance during the design of the twin-tunnel construction using the artificial horizontal ground freezing method.

scholarly journals Study on environmental impact of artificial horizontal freezing method in subway connecting passage

2020 ◽  
Vol 198 ◽  
pp. 04023
Author(s):  
Changyi Yu ◽  
Mingyue Lu
Keyword(s):  
Numerical Simulation ◽  
Environmental Impact ◽  
Simulation Method ◽  
Simplified Model ◽  
Thermophysical Parameters ◽  
Freezing Method ◽  
Geological Conditions ◽  
Complex Boundary ◽  
Artificial Freezing ◽  
Artificial Freezing Method

When the subway is built in complex urban strata, especially when excavating near buildings, it is necessary to strictly control the freezing amount by adopting artificial freezing method. At present, the theoretical calculation is aimed at the frozen rise under ideal conditions, but for complex geological conditions, the simplified model results are difficult to meet the actual requirements. However, numerical calculation can adapt to complex strata and complex boundary conditions. Therefore, in this paper, the environmental impact of artificial horizontal freezing method in subway connecting passage is studied by numerical simulation, and the change of thermophysical parameters with the change of temperature field is considered in the simulation. The simulation method in this paper provides guidance for actual construction.

scholarly journals STUDY OF APPLE RESISTANCE TO SPRING FROSTS BY ARTIFICIAL FREEZING METHOD

2019 ◽  
Vol 58 (1) ◽  
pp. 226-232
Author(s):  
Z. E. Ozherelieva ◽  
◽  
N. G. Krasova ◽  
A. M. Galasheva ◽  
◽  
...  
Keyword(s):  
Freezing Method ◽  
Artificial Freezing ◽  
Spring Frosts ◽  
Artificial Freezing Method

scholarly journals Investigation of Frost-Heaving Characteristics of Horizontal- Cup-Shape Frozen Ground Surface for Reinforced End Soil Mass in Shield Tunnel Construction

2017 ◽  
Author(s):  
Yongxing Zhang ◽  
Ting Zhang ◽  
Ping Yang
Keyword(s):  
Ground Surface ◽  
Soil Mass ◽  
Shield Tunnel ◽  
Frozen Ground ◽  
Frost Heaving ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Freezing ◽  
Shape Frozen ◽  
Artificial Freezing Method

Artificial freezing method is commonly adopted for reinforcingend soil mass of shield tunnel in the weak and rich aqueousformation, which is expected to prevent the construction riskin the originating and arriving of shield machine, whereas thearrangement of freezing pipes is sometimes varied due to variouscomplex limitations, and the corresponding frost-heavingcharacteristics of ground surface also differs from others. Inthis paper, a case of artificial freezing end soil mass with cupshape arrangement of horizontal freezing pipes is studied byfield investigation and numerical analysis, in which a numericalmodel coupled with water-heat-force interactions is proposedfor appropriately evaluating the frost-heaving characteristicsof ground surface in artificial freezing method. Theresults demonstrate that all the considered factors on brinetemperature, buried depth and cup bottom thickness have significantlyinfluences of frost-heaving characteristics of groundsurface in the artificial ground freezing (AGF) with cup shapearrangement of horizontal freezing pipes, in which the frostheave displacement of horizontal-cup-shape frozen groundsurface is increased with the increasing brine temperature andburied depth, whereas that is decreased with the increasing cupbottom thickness.

Stress Analysis of Pipeline Subjected to Differential Frost Heave

2013 ◽  
Author(s):  
Yan Di ◽  
Jian Shuai ◽  
Lingzhen Kong ◽  
Xiayi Zhou
Keyword(s):  
Strain Analysis ◽  
Element Model ◽  
Frozen Soil ◽  
Computational Method ◽  
Frost Heave ◽  
Safe Operation ◽  
Stress Strain ◽  
Segregation Potential ◽  
Differential Frost Heave ◽  
Design Construction

Frost heave must be considered in cases where pipelines are laid in permafrost in order to protect the pipelines from overstress and to maintain the safe operation. In this paper, a finite element model for stress/strain analysis in a pipeline subjected to differential frost heave was presented, in which the amount of frost heave is calculated using a segregation potential model and considering creep effects of the frozen soil. In addition, a computational method for the temperature field around a pipeline was proposed so that the frozen depth and temperature variation gradient could be obtained. Using the procedure proposed in this paper, stress/strain can be calculated according to the temperature on the surface of soil and in a pipeline. The result shows the characteristics of deformation and loading of a pipeline subjected to differential frost heave. In general, the methods and results in this paper can provide a reference for the design, construction and operation of pipelines in permafrost areas.

Microstructure-Based Random Finite Element Method Simulation of Frost Heave: Theory and Implementation

2018 ◽  
Vol 2672 (52) ◽  
pp. 347-357 ◽  
Author(s):  
Shaoyang Dong ◽  
Xiong (Bill) Yu
Keyword(s):  
Finite Element ◽  
Ground Surface ◽  
Finite Element Method Simulation ◽  
Element Model ◽  
Frozen Soil ◽  
Traffic Load ◽  
Frost Heave ◽  
Holistic Model ◽  
Water Pipes ◽  
Random Finite Element

Frost heave can cause serious damage to civil infrastructure. For example, interactions of soil and water pipes under frozen conditions have been found to significantly accelerate pipe fracture. Frost heave may cause the retaining walls along highways to crack and even fail in cold climates. This paper describes a holistic model to simulate the temperature, stress, and deformation in frozen soil and implement a model to simulate frost heave and stress on water pipelines. The frozen soil behaviors are based on a microstructure-based random finite element model, which holistically describes the mechanical behaviors of soils subjected to freezing conditions. The new model is able to simulate bulk behaviors by considering the microstructure of soils. The soil is phase coded and therefore the simulation model only needs the corresponding parameters of individual phases. This significantly simplifies obtaining the necessary parameters for the model. The capability of the model in simulating the temperature distribution and volume change are first validated with laboratory scale experiments. Coupled thermal-mechanical processes are introduced to describe the soil responses subjected to sub-zero temperature on the ground surface. This subsequently changes the interaction modes between ground and water pipes and leads to increase of stresses on the water pipes. The effects of cracks along a water pipe further cause stress concentration, which jeopardizes the pipe’s performance and leads to failure. The combined effects of freezing ground and traffic load are further evaluated with the model.

scholarly journals Self-realisation, self-actualisation and self-efficacy concepts theoretical analysis

2021 ◽  
Vol 27 (2) ◽  
pp. 7-15
Author(s):  
Tatyana Petrovna Opekina ◽  
Natalya Sergeevna Shipova
Keyword(s):  
Comparative Analysis ◽  
Theoretical Analysis ◽  
Goal Setting ◽  
Self Efficacy ◽  
Theoretical Study ◽  
The Self ◽  
Social Orientation ◽  
Similarities And Differences ◽  
The Individual ◽  
External Forces

This article presents the results of a theoretical study of self-realisation, self-actualisation and self-efficacy phenomena. The main aspects of understanding and correlating these phenomena in classical and modern Russian and foreign psychology are described. The highlighted concepts related to the phenomenon of self-realisation, both in the field of psychology and pedagogy. The similarities and differences of the self-realisation, self-actualisation, self-efficacy phenomena, as well as their correlation and comparison are presented. A comparative analysis of the studied concepts is given. According to the results of the theoretical analysis, the processes of self-realisation and self-actualisation are based on the inner motivation of a person to grow, develop personality, realise its potential. Both of these processes, due to their subjectivity, are difficult to observe and measure from the outside. We have highlighted the main differences, consisting in a greater awareness and orderliness of the process of self-realisation, as well as its predominantly "social" orientation, while self-actualisation is often associated with the struggle with external forces, the desire for self-realisation is rather approved and supported by the society. The concepts of self-realisation and self-efficacy are united by their inherent representation in the external plane of the life of the individual, as well as awareness, activity, goal-setting, and an orientation towards achieving success. In contrast to self-efficacy, self-release is a process rather than a sustainable phenomenon, and can be expressed both externally and internally through a connection with the value-semantic, motivational spheres of the individual.

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