Static pressure pipe field tests and simulation analysis

2019 ◽  
Vol 136 ◽  
pp. 04070
Author(s):  
Ma Lizhu

On the basis of the previous work, combined with the test piles collected from Shenyang area, this paper makes a detailed study of the current standard single safety factor design pile base method to the probability limit state design pile base method. The main work is statistical analysis, calculation of reliability index, analysis of the main factors affecting the reliability index of static pressure pipe pile and the analysis of its sub-coefficient coefficients, the reliability of its carrying capacity analysis has made a useful exploration.


Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6672
Author(s):  
Qiujiang Liu ◽  
Binghan Sun ◽  
Qinyao Yang ◽  
Mingli Wu ◽  
Tingting He

Harmonic overvoltage in electric railway traction networks can pose a serious threat to the safe and stable operation of the traction power supply system (TPSS). Existing studies aim at improving the control damping of grid-connected converters, neglecting the impedance frequency characteristics (IFCs) of the actual TPSS. The applicable frequency range of these studies is relatively low, usually no more than half of the switching frequency, and there is a large gap with the actual traction network harmonic overvoltage frequency range of 750 Hz–3750 Hz. In this paper, first, the IFCs of the actual TPSS in the wide frequency range of 150 Hz–5000 Hz are obtained through field tests, and the resonant frequency distribution characteristics of TPSS are analyzed. After that, the aliasing effect of the sampling process and the sideband effect of the modulation process of the digital control of the grid-connected converter are considered. Based on the relative relationships among the inherent resonant frequency of the TPSS, sampling frequency and switching frequency, an impedance matching analysis method is proposed for the wide frequency range of the vehicle–grid coupling system. By this method, the sampling frequency and switching frequency can be decoupled, and the harmonic overvoltage of traction network in the frequency range of two times switching frequency and above can be directly estimated. Finally, the method proposed in this paper is validated by the comparative simulation analysis of seven different cases.


2016 ◽  
Vol 61 (1) ◽  
pp. 137-156 ◽  
Author(s):  
Gang Wang ◽  
Wanpeng Huang ◽  
Lulu Sun ◽  
Mengmeng Wu ◽  
Xiaoqiang Zhang

AbstractMethane drainage method should be used before coal mining of many modern collieries because venti lation air methane is in sufficient to keep methane level within regulation values. The technology of high drilling methane drainage (HDMD) has been used for methane drainage although its effect is not very stable due to parameter design. The height of the fracturing zones is determined mostly according to empirical formula, on-site observation and numerical simulation analysis. In this paper, a method was introduced for determining the height of the air f ract uring zones (AFZs) based on its high similarity to the characteristics of Fracturing zones and the relationship between the height of Fracturing zones and the strain of overl ying rock strata. The application of water injection in both Shuangdingshan and Dongrong collieries found that the theoretically calculated the height of the Fracturing zones was approximately equal to the measured one in field tests within a permissible error of less than 5%, proving that the method is feasible. Based on the designed drainage parameters, the u tilization of HDMD technology in the collieries mentioned above found that the methane concentrations in both tail gate and upper corner were controlled in the ranges of 0.17% to 0.32% and 0.26% to 0.84%, respectively. These results showed that the water injection verified HDMD in Fracturing zones could effectively solve the problem of metha ne overrun and also verified the accuracy and reliability of its related theory.


2014 ◽  
Vol 496-500 ◽  
pp. 1587-1590
Author(s):  
Quan Liu ◽  
Xu Yang ◽  
Yi Ning Mu

CCD sensor can be used as the imaging device in the initial aiming processing for the beacon laser, and can also be used as the detecting device for the communication lasers optical axis alignment error of the targeting captured trace (APT) unit in space laser communication system. In this paper, based on a double-FPGA structure, we proposed technical solutions to realize the imaging CCD sensor driving and the laser spot position detection algorithm for the CX285AL image sensor by using the overall design of the system block diagram. The spot position detection wave door track centroid algorithm for CCD sensor is also studied by using the analysis of laser transmission characteristics of the atmospheric turbulence. The simulation analysis and field tests have been verified the feasibility of this approach.


Author(s):  
Likun Wang ◽  
Min Xiong ◽  
Jinyun Zhao ◽  
Hongchao Wang ◽  
Bin Xu ◽  
...  

The dynamic pressure transmitter based on piezoelectric dynamic pressure transducer is designed. The characteristic of dynamic pressure transmitter when pipeline leak happened is analyzed. The dynamic pressure signal is suitable for pipeline leak detection for quick-change of pipeline internal pressure, while the static pressure is suitable for slow-change of pipeline internal pressure. This paper indicated that the dynamic pressure signal could be adjust to this detection that the pressure changes quickly in the pipeline. Field tests show that the proposed method detects pipeline leak rapidly and precisely. The field test in 68.2 km pipeline shows that the least detected leakage ratio with dynamic pressure method is 0.6 percent pipeline throughput and location error is 80 m.


Redia ◽  
2020 ◽  
Vol 103 ◽  
pp. 115-120
Author(s):  
ALEXANDROS SOTIRIOS ANIFANTIS ◽  
ROBERTA MARZIALE ◽  
SIMONE PASCUZZI ◽  
JOSIP RAVLIC ◽  
NIKOLA GRUJIC ◽  
...  

The use of entomopathogenic nematodes (EPNs)as a non-chemical treatment system is one of the most mo-dern techniques promoted by the 2008/128/EC standards for the biological control of plant pathogens. The distri-bution ofEPNscould be carried out with the same sprayers used for the distribution of pesticides. This research is focusedon the effects of the mechanical stress due to hydraulic compression on EPNsItalianstrains,Stei-nernemafeltiaeand Heterorhabditisbacteriophora, to assess their residual strength and vitality under laboratory tests. Liquid suspensions of nematodes were subjected to 8 different levels of hydrostatic pressure from 5 to 40 bar. The hydraulic compression test was conducted through a hydrostatic compression system specifically de-signed for the experimental test. Although correlation curves show an increment of14%in nematode mortality, the statistical analysisdid not show any significant effect of static pressure on the vitality and infectivity of EPNs, that makes them suitable for field application with sprayers. These preliminary positive results on the effects of compression on the viability of EPNsare preparatory to subsequent field tests under high pressure


2021 ◽  
Vol 13 (20) ◽  
pp. 11239
Author(s):  
Xiaoping Ji ◽  
Honglei Lu ◽  
Cong Dai ◽  
Yonggen Ye ◽  
Zhifei Cui ◽  
...  

This paper presents a study of the properties of soil–rock mixtures (SRM) prepared by the vibration compaction method. First, the results of laboratory experiments and field tests are compared to determine the reasonable parameters of the vibration compaction method (VCM) for soil–rock mixtures. The compaction characteristics, CBR, and resilient modulus of the laboratory-prepared soil–rock mixtures by the static pressure compaction method (SPCM) and vibration compaction method are compared. The effects of the soil to rock ratio and the maximum particle size and gradation on the compaction characteristic, resilient modulus and CBR of soil–rock mixtures prepared by the vibration compaction method are investigated. Finally, field measurements are subsequently conducted to validate the laboratory investigations. The results show that the reasonable vibration frequency, exciting force, and static surface pressure of the vibration compactor for soil–rock mixtures are recommended as 25 Hz, 5.3 kN, and 154.0~163.2 kPa, respectively. Soil–rock mixtures prepared by vibration compaction method has smaller optimum water content and gradation variation and larger density than specimens prepared by the static pressure compaction method, and the CBR and resilient modulus are 1.46 ± 0.02 and 1.16 ± 0.03 times those of specimens prepared by the static pressure compaction method, respectively. The ratio of soil to rock, followed by the maximum particle size, lead obvious influences on the properties of soil–rock mixtures. Moreover, the results show that the CBR and resilient modulus of soil–rock mixtures prepared by vibration compaction method have a correlation of 86.9% and 89.1% with the field tests, respectively, which is higher than the static pressure compaction method.


2008 ◽  
Vol 44-46 ◽  
pp. 503-508
Author(s):  
Xiao Ying Zhang ◽  
Cun Lu Dang ◽  
L. Chai ◽  
C.P. Jiang

In order to eliminate the disadvantages of the traditional electro-hydraulic converters in the turbine governor, a new electro-hydraulic converter with strong restoring-motion was studied in this paper. The basic structure and working principal were analyzed, and the basic characteristics were described in detail. The simulation analysis of its dynamic characteristics was made by using Simulink software and the methods for improvement of the performances were suggested. The results of field tests indicated that the performance indexes of the hydro-turbine governors with this new technology were conformable to or higher than GB. It is concluded that the new electro-hydraulic converter has a promising future in engineering applications, especially in turbine governing systems that suffer from jam fault.


2012 ◽  
Vol 166-169 ◽  
pp. 1345-1352
Author(s):  
Jian Bin Zhao ◽  
Chao Xu ◽  
Hui Guo

Vertical ultimate bearing capacity of static pressure pipe pile is influenced by comprehensive factors, such as pile body, soil around pile and construction conditions., and the relationship between the impact factors and ultimate bearing capacity of a single pile is highly complexity and non-linear. This paper is based on collecting the data from static load tests in typical geological conditions of Liao-shen area, construction records, and test pile sites. And then combine analysis of principal component with SVM to analysis the prediction of the single pile’s vertical ultimate bearing capacity. This model can reduce the number of SVM input variable dimension to improve speed of training support vector effectively. At the same time it can eliminate the influence factors of multiple correlation. The results show that the proposed principal component analysis SVM model has good predictive accuracy and generalization ability, and opens up new avenue of research for analysis of static pressure pipe pile vertical bearing properties.


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