scholarly journals Theoretical Research and Numerical Simulation on Water Resistance Mechanism of Textile Bag in Water Passage

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Ang Li ◽  
Yuxuan Yang ◽  
Mingcheng Zhu ◽  
Wenzhong Zhang ◽  
Bingnan Ji ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Water Resistance ◽  
Simulation Analysis ◽  
Water Pressure ◽  
Water Inrush ◽  
Deformation Characteristics ◽  
Water Blocking ◽  
The Stability ◽  
Water Passage

It is an important problem in the mine water disaster prevention and control to control the large passage moving water. Traditional grouting technology is to put coarse aggregate and fine aggregate downward first and then grouting treatment. But the aggregate and cement flow distance is long, consumption is large, cost is high, and easy to appear secondary water inrush. Centering on the technical difficulties in the rapid construction of the blocking body of the moving water passage, a water-blocking textile bag was invented. The purpose of blocking the tunnel water inrush was achieved by grouting inside the bag body, which fundamentally realized the rapid blocking of the large passage through water under the condition of moving water. However, the mechanism, water plugging law, and design parameters of water blocking roadway with textile bag are still unclear. In this paper, the slip law and stability of the textile bag in the moving water and the deformation characteristics caused by the dynamic water pressure are theoretically analyzed and simulated. Through theoretical analysis, the ultimate antihydraulic stress value of a textile bag of a certain specification is calculated, and the parameters of the textile bag that affect the stability of the bag body are also determined. Xflow was used for numerical simulation analysis to study the deformation characteristics of the textile bag under water and the law of water barrier. The simulation analysis focuses on the water resistance effect and flow field distribution characteristics of the textile bag in the water passage under the condition of low flow rate and low pressure, as well as the stability and self-deformation characteristics of the textile bag under the condition of high flow rate and high pressure. The accuracy of the limit resistance to water pressure of the textile bag obtained from theoretical analysis is verified. The results show that the theoretical analysis is consistent with the simulation results. The textile bag can realize the fast controllable plugging of the large water passage of moving water within the limit of the antihydraulic stress.

FLAC3D Numerical Simulation Study on Deformation of Subgrade Construction Process

2011 ◽  
Vol 90-93 ◽  
pp. 466-470
Author(s):  
Ya Ni Lu ◽  
Gai Wei Li
Keyword(s):  
Numerical Simulation ◽  
Elastic Modulus ◽  
Simulation Study ◽  
Simulation Analysis ◽  
Lateral Displacement ◽  
Unit Weight ◽  
Deformation Characteristics ◽  
Construction Process ◽  
Main Research ◽  
Road Slope

Numerical simulation analysis of the deformation characteristics in the construction process of subgrade are conducted. Based on the different filling unit weight and roadbed elastic modulus conditions, the main research is that vertical settlement of roadbed center and the horizontal lateral displacement of road slope toe change with the increase of the depth of filling. It is believed that the lightweight filling should be selected or the roadbed elastic modulus will be enhanced as much as possible under the condition that satisfies various standard, which can improve the settlement deformation of highway.

Theoretical Analysis and Numerical Simulation of Oil Lubricated Foil Bearing With Elastic Supported Bump Foil Structure

2016 ◽  
Author(s):  
Guanghui Zhang ◽  
Qiang Chen ◽  
Jiajia Yan ◽  
Xianghe Wang ◽  
Zhansheng Liu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Reynolds Equations ◽  
Rotating Speed ◽  
Flexibility Matrix ◽  
Cavitation Effect ◽  
Foil Bearing ◽  
Deformation Equation ◽  
Bearing Load ◽  
The Stability

The oil lubricated multi-leaf foil bearing is developed to meet the demand of high rotating speed for hydraulic turbo-pump, where the lubricated oil is easy to obtain. For the stability of this kind oil lubricated foil bearing needs to be guaranteed, the bearing with elastic supported bump foil structure is proposed to improve the performance of foil bearing. Theoretical analysis and numerical simulation is carried out in this paper. The film thickness expression of multi-leaf foil bearing is established for the cases with and without top foil deformation. The total flexibility matrix considering elastic supported bump foil structure is developed based on Castigliano’s theorem. By employing the Reynolds boundary condition, the oil cavitation effect is presented. The established flexibility matrix is substituting into classical incompressible Reynolds equation, then the deformation equation of the foil and Reynolds equations are solved coupling by successive over relaxation method. The static characteristics such as pressure distribution, bearing load and static equilibrium position are obtained. By employing the perturbation method to Reynolds equations and foil deformation equation, the dynamic characteristics of multi-leaf foil bearing with elastic supported bump foil structure are acquired. The stability of the bearing is analyzed and compared with other type bearings by Routh-Hurwitz method. The effects of bearing load and sommerfeld parameter on the stiffness and damping coefficients are studied. The results indicate that the performance of foil bearing with elastic supported bump foil structure is improved and this kind bearing is suitable for high rotating speed application.

scholarly journals Numerical Simulation Analysis of New Steel Sets Used for Roadway Support in Coal Mines

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 606 ◽  
Author(s):  
Qinghai Li ◽  
Jingkai Li ◽  
Jinpeng Zhang ◽  
Changxiang Wang ◽  
Kai Fang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Simulation Analysis ◽  
Coal Mines ◽  
Soft Rock ◽  
Observation Point ◽  
Surrounding Rock ◽  
Surrounding Rock Control ◽  
Roadway Support ◽  
Two Sides

The surrounding rock control is a tough issue in the roadway with the swelling soft rock. The steel set is an important material for the control of swelling soft rock roadways. However, traditional steel sets failed to prevent the expansive pressure of the soft rock. Based on traditional steel sets, this paper developed a new steel set through both theoretical analysis and numerical simulation. The results showed that the new steel set was the set with the roof beam 1000 mm from the top of the set and the floor beam 400 mm from the bottom end of the set. The maximum deformations of the roof-floor and two sides of the ventilation roadway controlled by the best-improved set at the observation point were 147 mm and 108 mm, respectively. So, the best-improved set can effectively control the surrounding rock of the ventilation roadway. This provides an effective method for the surrounding rock control in extremely soft rock roadways.

Study on Numerical Simulation and Safety Analysis of Floor Water Inrush above Confined Water in Deep Mine

2012 ◽  
Vol 616-618 ◽  
pp. 267-271
Author(s):  
Jian Jun Shen ◽  
Wei Tao Liu ◽  
Yun Juan Liu
Keyword(s):  
Numerical Simulation ◽  
Water Pressure ◽  
Water Inrush ◽  
Continuum Theory ◽  
Imaging Method ◽  
Confined Water ◽  
Floor Rock ◽  
Deep Mine ◽  
Fractured Zone ◽  
Water Bursting

Mine water accident due to the mining above confined water is one of the main factors which affects and threatens safety in the coal production, especially for deep mine. Finding out the mine hydrogeological conditions, deepening the research of water inrush mechanism, and taking the effective safety measures of water bursting prevention, are all the key issues of mining under water pressure safely. Based on fractured rock mass equivalent continuum theory, according to drilling imaging method and water pressure test in borehole, in this paper we focus on discussing the water inrush of the floor rock , determining the floor rock permeability tensor with correction method and simulating the floor inrush problem by coupling stress field and seepage field theory and using anisotropic seepage model with FLAC3D. The results show that, the depth of destroyed floor in normal area and fractured zone in fault are about 30m and 58m respectively. According to empirical equation and numerical simulation, we get the results that the effective protection layer thicknesses are 82m and 115m respectively, and it has presented dangers in fault fractured zone based on the water bursting coefficient method.

Fluid-Solid Coupling Numerical Simulation Analysis of Impermeable Rock Mining Seam Floor Failure

2014 ◽  
Vol 1010-1012 ◽  
pp. 1527-1530
Author(s):  
Chun Jie Song ◽  
Cheng Fan
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Water Inrush ◽  
Three Dimensional ◽  
Deep Understanding ◽  
Simulation Method ◽  
Relevant Information ◽  
Simulation Software ◽  
Pressurized Water ◽  
Floor Failure

Based on a deep understanding of FLAC 3D numerical simulation software and the solid-liquid coupling theory and calculation method, this paper established a mining three-dimensional mechanical model under the pressurized water .Using the numerical simulation method, this paper systematically analysis deformation Laws of stress distribution of mining floor, bottom stress, its plastic zone and floor failure depth. By analyzing water inrush flow-solid coupling seepage problem under the conditions of coal mining, and compares with relevant information, verify the rationality of the existing theories and engineering measures, provide a theoretical basis for seeking security and economic exploitation of technical measures.

scholarly journals Numerical Simulation of Seepage and Deformation in Excavation of a Deep Foundation Pit under Water-Rich Fractured Intrusive Rock

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Changfeng Yuan ◽  
Zhenhui Hu ◽  
Zhen Zhu ◽  
Zijin Yuan ◽  
Yanxiang Fan ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Inrush ◽  
Risk Level ◽  
Silty Clay ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit

Water is one of the major risk sources in the excavation of deep-large foundation pits in a water-rich area. The presence of intrusive broken diorite porphyrite in the stratum aggravates the risk level of deep foundation pits. Based on a geological survey report and design documents of parameter information, MIDAS/GTS software was used to perform the numerical simulation of an engineering example of a deep foundation pit project of ultradeep and water-rich intrusion into the broken rock station of subway line 4 in a city. The simulation results show the characteristics of seepage path evolution, seepage aggregation areas and points, and the effect of seepage on the deformation of a deep foundation pit during the whole construction of this deep foundation pit. The results show that with the precipitation-excavation of the deep foundation pit, the pore water pressure at the bottom of the foundation pit follows a distribution of three “concave” shapes. High-permeability pressure zones are found around the foundation pit, intruding broken diorite porphyrite zones, and middle coarse sand zones. With further excavation of the foundation pit, the seepage pressure in the middle part of the foundation pit gradually decreases, and the two “concave” distributions in the middle gradually merge together. After excavation to the bottom of the pit, the pore water pressure at the bottom is distributed in two asymmetrical “concave” shapes, and the maximum peak of pore water pressure is found at the intrusion of fractured porphyrites prone to water inrush. The four corners of the foundation pit are prone to form seepage accumulation zones; therefore, suffosion and piping zones are formed. The surface settlement caused by excavation is found to be the largest along the longitudinal axis of the deep foundation pit, whereas the largest deformation is found near the foundation pit side in the horizontal axis direction of the foundation pit. With the excavation of the deep foundation pit, the diaphragm wall converges to the foundation pit with the maximum deformation reaching about 25 mm. After the first precipitation-excavation of the deep foundation pit to the silty clay and the bottom of the pit with the largest uplift, with further precipitation-excavation of the deep foundation pit, the uplift at the bottom of the deep foundation pit changes only slightly.

scholarly journals Analysis of Centroid Trajectory Characteristics of Axial-Flow Pump Impeller Under Hydraulic Excitation

2021 ◽  
Vol 9 ◽  
Author(s):  
Xiaohui Duan ◽  
Fangpin Tang ◽  
Hao Xu ◽  
Jian Chen ◽  
Qun Lu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Field Test ◽  
Water Pressure ◽  
Axial Flow ◽  
Pump Unit ◽  
Pump Impeller ◽  
Time Frequency ◽  
Axial Flow Pump ◽  
Flow Pump

The hydraulic excitation characteristics of axial flow pump unit are studied through theoretical analysis, numerical simulation and field test in this paper. The correlation between impeller hydraulic and radial vibration displacement of impeller centroid is obtained through theoretical analysis. Through the 1-way fluid-solid-interaction (FSI) numerical simulation, the distributions of water pressure and displacement on the impeller surface are obtained, and the time-domain and frequency-domain characteristics of transient hydraulic and radial displacement are revealed. Through the field test, the external characteristics of axial flow pump unit and the time-frequency characteristics of the pressure pulsation at the measuring points beside the inlet of the impeller are obtained. The comparisons between simulation results and experimental results show that the former is accurate and reliable.

scholarly journals Deformation and Stress Distribution of the Effective Water-Resisting Rock Beam under Water-Rock Coupling Action inside the Panel Floor

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Baojie Fu ◽  
Hualei Zhang ◽  
Min Tu ◽  
Xiangyang Zhang
Keyword(s):  
Elastic Modulus ◽  
Virtual Work ◽  
Water Pressure ◽  
Water Inrush ◽  
Confined Water ◽  
Analysis Model ◽  
Floor Rock ◽  
The Stability ◽  
Effective Water ◽  
Rock Beam

The stability of panel floor, which is above confined water, is the key to determine the water inrush from the panel floor. Based on the characteristics of “lower three zones” of the panel floor, the mechanics analysis model of a floor water-resisting rock beam is established. Then, by the principle of virtual work and energy functional variational conditions, the trends of deflection and internal stress are researched in the effective water-resisting rock beam under the combined action of mining stress and water pressure. And how to determine its stability is acquired. According to the geological and mining conditions of A3 coal seam in Panxie mining area of Huainan Mining Group, three factors influencing on the stability of the floor rock beam are analyzed, such as elastic modulus, coefficient of viscosity, and water pressure. It is shown that the elastic modulus plays the most important role on the deformation of the rock beam. So, for improving the mechanical properties of the rock beam, the reinforcing floor technique has been proposed. On the one hand, it is contributed to improve the ability for resisting floor deformation. On the other hand, it can increase the coefficient of rock viscosity in water damage zones and reduce the speeds of loading and deformation in the whole rock beam. Hydrophobic decompression can effectively reduce the stress on the boundary of the rock beam, and the stability is enhanced. The research results have a guiding significance for determining whether there are water inrush risks in the panel above the confined aquifer.

Numerical Simulation Analysis on Stability of Coal Pillar of Empty Mine Goaf in North of Shanxi Province

2013 ◽  
Vol 470 ◽  
pp. 205-210
Author(s):  
Hao Tang ◽  
Zi Guang He ◽  
Hai Bo Lian
Keyword(s):  
Numerical Simulation ◽  
Simulation Analysis ◽  
Coal Pillar ◽  
Shanxi Province ◽  
Analysis Model ◽  
Term Stability ◽  
Long Term Stability ◽  
The Law ◽  
The Stability

The analysis model of coal pillar of a empty mine goaf in north of Shanxi province was constructed and the process of coal pillar from formation to weathering was simulated through the application of software of FLAC3D in this article. The stressstrain and the law of plasticity transformation of coal pillar from formation to weathering were analyzed and the long-term stability of coal pillar was forecasted. The result showed that the stability of coal pillar was bad for excessive excavated and weathering and the coal pillar will be broken easier for pressure and shear.

scholarly journals Investigation of Anisotropy on Deterioration of Mechanical Parameters of Layered Rock Under Freeze-thaw Cycles

2021 ◽  
Author(s):  
Guangkeng Zhang ◽  
Lianrong Wu ◽  
Huiyun Wang ◽  
Zhipeng Li ◽  
Baosheng Shi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Slope ◽  
Simulation Analysis ◽  
Deformation Characteristics ◽  
Mechanical Parameters ◽  
Compression Tests ◽  
Freezing And Thawing ◽  
Copper Mine ◽  
Freeze Thaw ◽  
Layered Rock

Abstract The evaluation of slope deformation and stability under freeze-thaw cycles is an important research direction and a challenge for geotechnical engineering in cold regions. However, most previous studies only considered the influence of the number of freeze-thaw cycles, but ignored the anisotropic characteristics of layered rock slopes. Meanwhile, the number of freeze-thaw cycles and the bedding dip are rarely considered in previous numerical simulations. Based on this background, the carbonaceous slate of the Pulang copper mine in China was used as the sample material to perform uniaxial compression tests on seven types of carbonaceous slate with different bedding dip angles after completing six different times of freeze-thaw cycles. The test results are applied to the numerical simulation analysis of the deformation characteristics and stability of the layered rock slope of the copper mine. The results show that freezing and thawing will cause layered rock degradation effects, thereby reducing rock mechanical parameters, and the influence is most obvious when the bedding dip is approximately 45°. In the numerical simulation, it is found that the deformation characteristics and stability change trend of the layered rock slope are similar to the above-mentioned experiments. In addition, it is necessary to consider the number of freeze-thaw cycles and the bedding dip to avoid too much difference for the maximum horizontal displacement of a layered rock slope. This study provides a feasible evaluation plan for the deformation characteristics and stability of the layered rock slope in Pulang area of China.

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