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Study on numerical simulation of fully mechanized top coal’s caving property of Tang gong ta coal mine Quanming Liu 5 Qingniangou Road, Heping Street, Chaoyang District, Beijing, P.R.China quanming_liu@163.com Keywords: fully mechanized top coal caving mining;top coal’s caving property; numerical simulation; abutment pressure Abstract.Using numerical simulation method,fully mechanized top coal’s caving property of Tang gong ta coal mine was studied.The results show at primary mining period of fully mechanized working face, there were stress concentration regions at the front and rear of coal wall,but it was not distinct in the front and top coal’s caving property was not ideal.When it advanced to 84m of the working face,there would be obvious peak stress at the front and rear of coal wall.
Fully mechanized top coal’s caving property is cave-in and drain feature,it is parameter of complexity for top coal’s cave-in and drain under abutment pressure.Form natural fracture’s extension to strength fracture appearance,then finally release from discharge opening,fully mechanized top coal caving mining is influenced by many factors.In order to understand the feasibility of specific mine after fully mechanized top coal caving mining, the numerical simulation study of fully mechanized top coal’s caving property is necessary[6~8].
According to coal seam conditions of Tang gong ta coal mine to establish FLAC3D numerical model.Simulative height of model is 96m,move towards length is 240m.There are 20m affected area at two sides respectively.The advance length is 250m,and coal seam thickness is 14.44m.
Equivalent load is calculated as equation 1: (1) ——120m above the simulation model is not running ——The average corresponding density of coal strata is 2400kg/m3 ——Acceleration of gravity is 9.81,unit is m/s2 Coal rock mechanical parameters in accordance with measured data in the laboratory,if there is no experimental data referring to the average value of the lithology.
Fig. 2 Model occurrence Fig. 3 Stress state of model Top Coal’s Caving Property Analysis Fig. 4 shows top coal’s destructive state when fully mechanized top coal mining overall height at one time.

Previous studies about delayed mechanical behavior of concrete have pointed out an increase of delayed strains with the temperature rise: the basic creep can be multiplied by a factor 10 at 80°C, and coupling between creep and heating can lead to damage and to transient thermal creep.
So, the material properties just before the LOCA depend on the solicitation history since the concrete pouring.
Chemical reaction with pore pressures: Alkali reaction and delayed ettringite formation belong to this second family of chemical reaction affecting the concrete behavior.
Struct. 44 1821–35 [9] Multon S and Sellier A 2016 Cement and Concrete Research Multi-scale analysis of alkali – silica reaction ( ASR ): Impact of alkali leaching on scale effects affecting expansion tests Cem.
Eng. 1–26 [11] Schutter G De and Taerwe L 1996 Degree of hydration-based description of mechanical properties of early age concrete Mater.

Spline-based Finite Element Analysis in Composite Laminates Mechanical Properties Fengxiang You 1, 2, Fei Zhang 2, BuLei Zuo 2 (1, Automation Control Department , Huazhong University of Science and Technology, Wuhan, Hubei Province, China, 470073 2, Nanjing Institute of Railway Technoiogy , Jiangsu Province,China, 215137 ) About The Author：Fengxiang You（1960-），Male, Tianjin, professor, ph.
The geometric parameters of the composite laminate in the engineering structure tend to have random properties.
Composite material has been widely applied in modern industry because of its features as being stronger rigidity, tougher stiffness as well as its physical and mechanical properties which can be designed to its advantage.That's why mechanical characteristic of laminated plates in compound materials has even more aroused people's interest.
Example 2, the geometric properties of laminated plates and loaded situation with Example 1.
Layers of the same material properties: Material density, antisymmetric angle:().

By eliminating the above factors, an abnormal three-stage trend of viscosity changes is observed finally.
Viscosity in both the high-temperature and supercooled liquid regions is one of the most important dynamic properties.
The thermodynamics and dynamics of the liquids are the keys to understanding the properties.
Zhang, Formation, thermal stability and mechanical properties of Cu-Zr-Al bulk glassy alloys, Mater.
Inoue, High glass-forming ability and good mechanical properties of new bulk glassy alloys in Cu–Zr–Ag ternary system, J.

Out of the monitored properties, the specific lightness of paper surface showed the greatest stability (97.8%).
The papers exposed to light for a long time change their optical, mechanical and physicochemical properties.
The changes in optical, mechanical and physicochemical properties are mainly due to the effect of heavy active ultraviolet part of the incident light.
Summary The obtained results allow us to conclude that even current wood-free office paper of high quality when exposed to UV radiation shows the changes in their properties.
In: Lejeune, A., Deprez, T., Cellulose: Structure and Properties, Derivates and Industrial Uses.

In this work, optical microscopy data are analysed in support of flexural properties of kaolin coated lumber woods.
Correlating mechanical and thermal properties of sodium silicate-fly ash geopolymers.
Factor affecting early compressive strength of alkali activated fly ash (OPC-free) concrete.
[8] Wang, Li and Yan (2005).Synthesis and mechanical properties of metakaolinite-based geopolymer.
Development and properties of low-calcium fly ash based geopolymer concrete.Research report GCI.

There are several factors that affect the performance, such as; oxidation, mechanical damages, manufacturing oriented problems (thermal residual stresses) etc.
In other words, the TBC performance is governed by thermo-mechanical interactions between its constituents.
One of other factors of utmost importance is the BC yielding caused by imperfections or defects [3-5].
[15] Moskal, G., Thermal barrier coatings: characteristics of microstructure and properties, generation and directions of development of bond.
[21] Quested, P., Brooks RF., Chapman L., Morrell R., Youssef Y., and Mills KC., Measurement and estimation of thermophysical properties of nickel based superalloys.

In addition, changes in particle sizes, pre-treatment, temperature and other factors have also been discussed towards the heavy metal adsorption.
Some factors may affect the adsorption capacity of heavy metals by SCB, such pH, temperature, initial heavy metal concentration, biosorbent, dose, biosorbent size, ionic strength, co-ions and others.
Although this percentage may affect the solidification properties of the specimens, but they still fit the standards.
The percentage of these agricultural wastes, their particles’ sizes and their pretreatment affect the mechanical properties of the matrices such as the density, the strength, the water absorption and others to be stored in the landfill.
Mokhtar, Mechanical properties of soft clay stabilized with cement-Rice husks (RH), 2011, unpublished

Rice protein could affect the pasting properties and textural properties of rice flour.
The formation of a gel or a paste is one of the principal factors that control the texture and quality of starch-containing food.
Pasting properties.
RVA pasting properties and textural properties.
Rice protein could affect the pasting properties and textural properties.

This paper, taking Dalian Spring Street subway station as the background, uses the finite difference software to establish 3-D finite element analysis model to simulate the effects of tunnel excavation on underground pipeline, in which different embedment, material properties and diameters are considered.
By analyzing of the settlement and deformation law of pipeline, the least affected pipeline conditions are drawn to provide corresponding guidance for subsequent underground projects.
This series of unfavorable factors will have an adverse impact on pipeline buried into the surrounding soil, and even cause serious safety hazards on State Property, the normal life of the people [3-4].
To seize the main laws, ignoring secondary factors, the calculation process uses the following assumptions: Ÿ Consider pipelines as linear elastic constitutive, for its same diameter, wall thickness, and insignificant geometry deformation
This paper simulates the effects of a double-tube parallel tunnel excavation on underground pipeline in different embedment, material properties and diameters conditions.