scholarly journals Influence of Hole Arrangement on the Section of Cavity Formed by Cutting Blast

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xianglong Li ◽  
Qiang Li ◽  
Jianguo Wang ◽  
Zichen Wang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Tensile Stress ◽  
Theoretical Calculation ◽  
Hole Diameter ◽  
Charge Hole ◽  
Horizontal Distance ◽  
Tunnel Excavation ◽  
Calculation Results ◽  
The Difference

In order to optimize the arrangement of cutting holes in tunnel blast in Dahongshan Copper Mine, theoretical analysis and numerical simulation were combined to preliminarily determine the diameter of the hollow hole and the distance between the charge hole and the hollow hole during cut blast, which was verified through the field blast test. The research results show that with the increase of the hole diameter, the peak compressive stress of rock surrounding the empty hole gradually decreases, and the peak tensile stress gradually increases, which is consistent with the calculation results; when the hole diameter is 10 cm, the two first blast holes are arranged horizontally and 30 cm from the empty hole, two second blast holes are arranged vertically and 40 cm away from the empty hole, and the four third blast holes are arranged at a horizontal distance of 45 cm and a vertical distance of 45 cm from the empty hole; the contour area in numerical simulation is the maximum. The difference in contour area, contour width, and contour and contour height between the measured value and the simulation result is 5.3%, 3.3%, and 3.4%, respectively, indicating that the combination of theoretical calculation and numerical simulation is suitable for prediction of cavity section after blast in tunnel excavation.

Comparative Study on Ultimate Pullout Resistance Test and Theoretical Derivation of Flexible Pressurized Anchor with Numerical Simulation Result

2012 ◽  
Vol 268-270 ◽  
pp. 753-760
Author(s):  
Xuan Li Zhang ◽  
Wen Bin Wei
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Theoretical Derivation ◽  
Material Body ◽  
Pullout Resistance ◽  
Test Study ◽  
Simulation Calculation ◽  
Calculation Process ◽  
Calculation Results ◽  
Pressure Stress

The study on anchorage characteristics of flexible pressurized anchor should be along with theoretical analysis, numerical simulation and test study. Through comparing three calculation results, it is concluded that the theoretical analysis and numerical simulation can authenticate the correctness of calculation process each other; After considering the situation that friction coefficient changed with different contact pressure stress, the deviation of calculation of theory derivation and numerical simulation with experimental results significantly reduced; Anchor was simplified for anisotropic composite material body, which should be able to better reduce deviation among test, theoretical derivation and numerical simulation calculation.

Calculation of Axial Hydraulic Thrust of Francis Turbine

2012 ◽  
Author(s):  
XingYing Ji ◽  
Lai Xu ◽  
Xiao Liu
Keyword(s):  
Numerical Simulation ◽  
Theoretical Calculation ◽  
Significant Role ◽  
Model Test ◽  
Francis Turbine ◽  
Axial Thrust ◽  
Theoretical Methods ◽  
Calculation Results

Put forward a method of calculating the axial thrust of Francis turbine. To use numerical simulation computing the axial thrust on hub, shroud and blade of inner runner, combine theoretical methods calculating the pressure on hub and shroud of outer runner, finally the axial thrust of Francis turbine is obtained. The results of calculation agree with the results of model test. It is an effective way of gathering the theoretical calculation and numerical simulation to calculate the axial thrust of Francis turbine. In addition the static suction of turbine has great effect on calculation results of the axial thrust. The static suction of turbine plays a significant role on the lifting of turbine.

The Modal Analysis of Roller Chain Drives

2011 ◽  
Vol 291-294 ◽  
pp. 1551-1554 ◽  
Author(s):  
Bao Lin Li ◽  
Shuai Fan ◽  
Yan Zhang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Calculation ◽  
Natural Frequency ◽  
Engineering Application ◽  
Simplified Model ◽  
Harmonic Response ◽  
Roller Chain ◽  
Calculation Results ◽  
Chain Drives ◽  
Ansys Workbench

Aiming at calculating the natural frequency of roller chain drives, the software Catia was used for modeling the roller chain drives accurately and Ansys Workbench was applied to analyze the modal and harmonic response of the tension side chains, comparing the natural frequency and the theoretical calculation results of simplified model. The results showed that the deviation increased with the increase of the order of natural frequency and modal numerical simulation provides certain reference for engineering application.

scholarly journals Formula for determining the size of the air tank in the long-distance water supply system

2020 ◽  
Author(s):  
Xuyun Chen ◽  
Jian Zhang ◽  
Nan Li ◽  
Xiaodong Yu ◽  
Sheng Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Water Supply ◽  
Theoretical Calculation ◽  
Selection Process ◽  
Supply System ◽  
Water Supply System ◽  
Operating Parameters ◽  
Long Distance ◽  
Calculation Results ◽  
Simulation Results

Abstract In the long-distance water supply system, the air tank can effectively protect the water hammer when the pump stops, and the shape parameters of the air tank determine the protective effect. Based on the theory of rigid water body and harmonic vibration, this paper derived the calculation formulas for the surge and bottom pressure changing process of the air tank in the system with and without friction and impedance and put forward the theoretical method to estimate the air tank volume and established the relationship between the operating parameters and the volume. Combined with the actual water supply project, under different working conditions, the theoretical calculation results and numerical simulation results were compared and analyzed. The results showed that the theoretical calculation results of the system with friction and impedance had a better fitting performance than the numerical simulation results, and the operating parameters of the air tank derived after considering the influence of friction and impedance were accurate. This method can simplify the selection process of air tank body parameters. At the same time, the shape optimization of the air tank considering friction and impedance can be improved by 40–50% compared with the results of ignoring friction and impedance.

scholarly journals Study on Seismic Performance of Porcelain Pillar Electrical Equipment Based on Nonlinear Dynamic Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yaodong Xue ◽  
Yongfeng Cheng ◽  
Zhubing Zhu ◽  
Sheng Li ◽  
Zhenlin Liu ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Model ◽  
Electrical Equipment ◽  
Nonlinear Parameter ◽  
Seismic Excitation ◽  
Test Results ◽  
Nonlinear Seismic Response ◽  
Calculation Results ◽  
The Difference ◽  
The Impact

In order to consider the influence of nonlinear characteristics of porcelain pillar electrical equipment on the dynamic response under seismic excitation, a theoretical analysis method of nonlinear dynamics was raised to define the nonlinear parameter of the flange connection and establish a dynamic model of porcelain pillar electrical equipment. The theoretical analysis and the test results have a good degree of fitting, which verifies the correctness of the dynamic model and reveals the nonlinear seismic response law of the porcelain pillar equipment. According to the results, both the nonlinear calculation results of the displacement at the top end of the porcelain pillar and the stress at the bottom end of the porcelain pillar are smaller than the results in the linear calculation. The difference between them increases gradually with the increase of seismic excitation. The differences in displacement and stress at a seismic excitation of 0.5 g are 14.58% and 23.25%, respectively. When the nonlinear parameter increases to a certain value, the impact of maximum stress on the bottom of the porcelain pillar is very small and the change is not obvious. The research provides a theoretical reference for the seismic design of pillar electrical equipment.

scholarly journals Study on Control of Wall Deflection in Earth Stepped-Twin Retaining Wall Using Anchor Method by means of Numerical Simulation

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Kazuki Maehara ◽  
Akihiro Hamanaka ◽  
Takashi Sasaoka ◽  
Hideki Shimada ◽  
Seiya Sakuma
Keyword(s):  
Numerical Simulation ◽  
Soil Properties ◽  
Retaining Wall ◽  
Earth Pressure ◽  
Outer Wall ◽  
Horizontal Distance ◽  
Wall Deflection ◽  
The Earth ◽  
Adjacent Structures ◽  
The Difference

The demand for specific earth retaining wall methods is increasing along with the advancement and overcrowding of underground space use such as the presence of adjacent structures in an urban area. To cope with this, the method named earth stepped-twin retaining wall is increasingly being applied. However, there is a concern about the workplace if the earth pressure causes a heaving and pressing phenomenon from both ends of the retaining wall in the earth stepped-twin retaining wall. Therefore, we proposed the application of an anchor method that contains the inner and outer walls by using numerical simulation. The effects of the difference in soil properties, the horizontal distance between the outer and inner walls, and the depth of the outer wall embedment on the anchor were investigated. The results of this study show that the wall deflection of the inner wall could improve by adopting the anchor support. Besides, it was found that the inner wall can be efficiently suppressed by adopting the hybrid system with anchors and struts according to the soil properties, horizontal distance, and the depth of the outer wall.

Research on Influence of Thermosiphon Layout on Cooling Effect on Transmission Line Pile Foundation in Permafrost Region

2014 ◽  
Vol 530-531 ◽  
pp. 971-974
Author(s):  
Hao Lin Yu ◽  
Xue Yan Xu ◽  
Wei Wang ◽  
Ming Xuan Li
Keyword(s):  
Finite Element Method ◽  
Transmission Line ◽  
Pile Foundation ◽  
Research Work ◽  
Layout Design ◽  
Cooling Effect ◽  
Permafrost Region ◽  
Horizontal Distance ◽  
Calculation Results ◽  
The Difference

Research work on the thermosiphon layout design of transmission line pile foundation in Geermu permafrost region was performed by finite element method and the influence of thermosiphon layout design on the temperature of soil around pile foundation was calculated and analyzed. The numerical calculation results indicated that the cooling effect of thermosiphon was obvious, but the coolling effect varied with the difference of thermosiphon layout design. The more thermosiphon bars were laid out aound pile foundation, the lower the temperature of soil around pile foundation. The cooling effect of thermosiphon on pile foundation and soil became weaker and weaker with the increment of the horizontal distance between soil and thermosiphon-pile. The layout design of 12 thermosiphon bars was the best for the transmission line pile foundation in permafrost region.

Computation and Analysis of Buttressed Quay’s Floor

2014 ◽  
Vol 580-583 ◽  
pp. 2185-2188
Author(s):  
Qing Chen Ning ◽  
Xu Yang ◽  
Yan Shi ◽  
Lun Li
Keyword(s):  
Numerical Simulation ◽  
Vertical Plate ◽  
Vertical Direction ◽  
Bending Moment ◽  
3D Numerical Simulation ◽  
Simply Supported ◽  
Finite Element Software ◽  
Calculation Results ◽  
The Difference ◽  
Current Code

In the design and construction code for gravity quay, the inner floor of multi-ribbed buttressed quays generally is divided into two parts to calculate. The part within 1.5 times the rib spacing is as a three fixed edges and one simply-supported slab. The restriction effect of the three fixed edges is the same. However, because of the difference in thickness between vertical plate and rib with the change in the vertical direction of the flow, the effect of them is not the same. It will lead to the result deviating. Sometimes, there will be a phenomenon that the maximum bending moment of inner floor is smaller than the mid-span moment. Finite element software ANSYS was used to make a 3D numerical simulation on a buttressed quay in this paper. Shortcomings in the current code are addressed by comparing the calculation results. This can provide references for engineering design.

Effect Analysis of Nitrogen Injection on the Variation of “Oxidation Zone” in Coal Mine Gob Based on Numerical Simulation

2016 ◽  
Vol 9 (1) ◽  
pp. 47-54
Author(s):  
Jing Shen ◽  
Mingran Chang
Keyword(s):  
Numerical Simulation ◽  
Coal Mine ◽  
Heat Dissipation ◽  
Spontaneous Combustion ◽  
Oxidation Zone ◽  
Effect Analysis ◽  
Mine Fire ◽  
Nitrogen Injection ◽  
The Difference ◽  
Residual Coal

One of the main reasons for coal mine fire is spontaneous combustion of residual coal in gob. As the difference of compaction degree of coal and rock, the underground gob can be considered as a porous medium and divided into “three zones” in accordance with the criteria. The “three zones” are “heat dissipation zone”, “oxidation zone” and “choking zone”, respectively. Temperature programming experiments are taken and numerical simulation with obtained experimental data is utilized to analyze the distribution of “three zones” in this paper. Different width and depth of “oxidation zone” are obtained when the inlet air velocity is changed. As the nitrogen injection has inhibition effect on spontaneous combustion of residual coal in gob, nitrogen is injected into the gob. The widths of “oxidation zone” are compared before and after nitrogen injection. And ultimately the optimum location and volume of nitrogen injection are found out.

scholarly journals Comparison of Building Simulation Methods for Modeling Apartment Balconies

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3955
Author(s):  
Yonghan Ahn ◽  
Hanbyeol Jang ◽  
Junghyon Mun
Keyword(s):  
Heat Transfer ◽  
Air Temperature ◽  
Parameter Analysis ◽  
Interior Space ◽  
Heating And Cooling ◽  
Significant Difference ◽  
Calculation Results ◽  
Infiltration Parameter ◽  
The Difference ◽  
Heating And Cooling Load

The purpose of this study is to compare the load calculation results by a model using the air changes per hour (ACH) method and a model using an airflow network (AFN) and to ascertain what causes the difference between the two models. In the basic case study, the difference in the heat transfer distribution of the model in the interior space was investigated. The most significant difference between the two models is the heat transfer that results from infiltration. Parameter analysis was performed to investigate the relationship between the difference and the environmental variables. The result shows that the greater the difference is between the air temperature inside the balcony and the outdoor air temperature, and the greater the air flows from the balcony to the residential area, and the greater the heating and cooling load difference occurs. The analysis using the actual weather files of five domestic cities in South Korea rather than a virtual case shows that the differences are not so obvious when the wind blows at a constant speed throughout the year, but are dominant when the wind does not blow during the night and is stronger alongside the occurrence of sunlight during the day.

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