Land Subsidence Prediction Method of Power Cables Pipe Jacking Based on the Peck Theory

2013 ◽  
Vol 634-638 ◽  
pp. 3721-3724
Author(s):  
Yuan Liang Zhang ◽  
Yi Hu Zhang
Keyword(s):  
Land Subsidence ◽  
Prediction Method ◽  
Dominant Factor ◽  
Engineering Practice ◽  
Foundation Settlement ◽  
Power Cables ◽  
Overhead Transmission Line ◽  
Allowable Range ◽  
Calculation Results ◽  
Range Calculation

Overhead transmission line and cable are generally used for across or crossing the railway, highways and rivers.For higher deformation requirement of operation of the railway and highway foundation settlement,to ensure that the cable through the process of foundation in regulating the allowable range, calculation and prediction of foundation settlement is specially necessary.Based on the Peck theory, the dominant factor in foundation settlement-strata loss calculation method is introduced supplemented with measured settlement observation records in this paper,which confirmes that the calculation results are replicab in engineering practice.

Forecast Model of Phreatic Surface on Tailings Dam Based on GM-GRNN Theory

2010 ◽  
Vol 44-47 ◽  
pp. 3403-3407
Author(s):  
Fei Yue Wang ◽  
Zhi Sheng Xu ◽  
Long Jun Dong
Keyword(s):  
Prediction Method ◽  
Forecast Model ◽  
Random Disturbance ◽  
Tailings Dam ◽  
Phreatic Surface ◽  
Factors Affecting ◽  
Depth Analysis ◽  
Tailing Dam ◽  
Calculation Results ◽  
Surface Prediction

Due to the extremely complicated seepage boundary conditions of tailing dam, the calculation results adopting two-dimensional simplified theory may greatly different from the measured results. It is urgent need of an accurate calculation method to forecast phreatic surface. In-depth analysis of factors affecting tailings dam phreatic surface, phreatic surface prediction model based on GRNN and GM (1,1) was established. A tailing dam engineering is tested using this model. It shows that the model uses the advantages of "accumulative generation" of a Gray prediction method, which weakens the original sequence of random disturbance factors, and increases the regularity of data. It also makes full advantage of the GRNN approximation performance, which has a fast solving speed, describes the nonlinear relationship easily, and avoids the defects of Gray theory.

scholarly journals Calculating the load on the room cooling ceiling panel at convective heat gains

2020 ◽  
Vol 164 ◽  
pp. 02006
Author(s):  
Elena Malyavina ◽  
Alexander Lomakin
Keyword(s):  
Thermal Stability ◽  
Convective Heat ◽  
Convective Flow ◽  
Cooling System ◽  
Working Hours ◽  
Engineering Practice ◽  
Convective Heat Flux ◽  
Long Period ◽  
Radiant Cooling ◽  
Calculation Results

A well-known statement of the theory of thermal stability asserts that when a harmonically time-changing convective heat flux enters a room, it can only be assimilated by a radiant cooling system if the assimilating flow exceeds the perturbing convective flow in magnitude. However, in engineering practice, there are no purely radiant systems. Therefore, the article has considered a ceiling cooling panel as a room cooling system, the heat flow from which is of a radiant-convective nature. The convective heat access to the room is constant during the working hours from 9 a.m. to 6 p.m. The task of determining the load on the cooling system has been performed by calculations.. Herewith, the rooms of different internal thermal stability have been considered. According to the calculation results, it has been found that, since the amount of the heat gains remains constant for a long period of time, the process of the room cooling comes almost to a stationary state and does not depend on the room thermal stability with assimilated heat gains, the value of which in different options varied from 100 W to 1000 W. It has been found, that when the temperature difference between the panel surface and the surrounding surfaces increases, the proportion of the convective assimilating flow becomes bigger.

Matching Optimization of Impeller and Volute for Double-Channel with Double-Suction Pump

2014 ◽  
Vol 904 ◽  
pp. 311-314
Author(s):  
Bao Jie Luo ◽  
Lin Long Song ◽  
Pan Zhao
Keyword(s):  
Flow Characteristics ◽  
Prediction Method ◽  
Cross Sectional ◽  
Suction Pump ◽  
Uniform Distributions ◽  
Calculation Results ◽  
Tongue Position ◽  
Frequency Components ◽  
Suspended Matters ◽  
Double Channel

In order to study the matching optimization of the impeller and volute as well as the flow characteristics of double-channel with double-suction pump ,this paper based on CFD performance prediction method uses the same impeller to match the volute with different base diameters, guaranteeing the volute inlet width, flow cross-sectional area, and tongue position unchanged .The calculation results show that scheme A with the largest volute base diameter can not only achieve the excellent energy characteristics and the velocity-pressure uniform distributions, but also the exchange of the fluid energy is more sufficient in the volute. On one hand, a large clearance can not only make the movement interference intensity weaken between the impeller and volute, but also can decrease the high frequency components of the pressure pulsations .On the other hand, the big gap can maximum exert the pump effects to convey liquids containing solid suspended particles as well as the fibrous suspended matters. The research can not only provide some references to further study on matching optimization of the impeller and volute but also can contribute to the hydraulic design of the impeller and volute.

scholarly journals Estimating Remaining Useful Life for Degrading Systems with Large Fluctuations

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Dang-Bo Du ◽  
Jian-Xun Zhang ◽  
Zhi-Jie Zhou ◽  
Xiao-Sheng Si ◽  
Chang-Hua Hu
Keyword(s):  
Stochastic Process ◽  
Standard Deviation ◽  
Health Management ◽  
Prediction Method ◽  
Remaining Useful Life ◽  
Threshold Function ◽  
Engineering Practice ◽  
Practical Case ◽  
Degradation Data ◽  
Useful Life

Remaining useful life (RUL) prediction method based on degradation trajectory has been one of the most important parts in prognostics and health management (PHM). In the conventional model, the degradation data are usually used for degradation modeling directly. In engineering practice, the degradation of many systems presents a volatile situation, that is, fluctuation. In fact, the volatility of degradation data shows the stability of system, so it could be used to reflect the performance of system. As such, this paper proposes a new degradation model for RUL estimation based on the volatility of degradation data. Firstly the degradation data are decomposed into trend items and random items, which are defined as a stochastic process. Then the standard deviation of the stochastic process is defined as another performance variable because standard deviation reflects the system performance. Finally the Wiener process and the normal stochastic process are used to model the trend items and random items separately, and then the probability density function (PDF) of the RUL is obtained via a redefined failure threshold function that combines the trend items and the standard deviation of the random items. Two practical case studies demonstrate that, compared with traditional approaches, the proposed model can deal with the degradation data with many fluctuations better and can get a more reasonable result which is convenient for maintenance decision.

Numerical Prediction of Pump Performance Drop and Erosion Area due to Cavitation in a Double-Suction Centrifugal Feedpump

2011 ◽  
Author(s):  
Masahiro Miyabe ◽  
Hideaki Maeda
Keyword(s):  
Prediction Method ◽  
Cavitation Model ◽  
Blade Loading ◽  
Pump Performance ◽  
Impeller Outlet ◽  
Calculation Results ◽  
Erosion Area ◽  
Erosion Test ◽  
Cavitation Behavior ◽  
Operating Points

This paper presents the numerical cavitatoin prediction methods of pump performance drop and erosion area by using a commercial CFD code. A cavitation model which is so called full cavitation model was used to predict pump performance drop. Furthermore, some indexes which are associated with void fraction and static pressure rising were applied to estimate erosion area on the impeller blades. A centrifugal boiler feedpump with a double-suction was tested and the cavitation characteristics were visualized and compared with the calculated results at three pump operating points of 0.63Qopt, Qopt and 1.50Qopt, respectively. As a result, the calculated pump performance drop and cavitation behavior agree well qualitatively with the experimental ones. Based on the calculation results of partial flow rate, it was found that pump performance drop is caused when the cavity reaches the blade-to-blade throat at the hub-side and the decrease of blade loading at the impeller outlet. In addition, simple cavitatoin erosion indexes were applied to esitimate the erosion area. The paint erosion test was conducted and compared with the calculated results at three pump operating points. One of them is in good agreement with the experiment. It is concluded that the present numerical cavitation prediction method is available at a design process of the pump.

Aerodynamic Design of a Power Turbine for an Aircraft Derivative Marine Gas Turbine

1988 ◽  
Vol 110 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Guiming Ji ◽  
Zengxiang Tan ◽  
Mingchang Zhang
Keyword(s):  
Gas Turbine ◽  
Design Methodology ◽  
Aerodynamic Characteristics ◽  
Engineering Practice ◽  
Variable Geometry ◽  
Aerodynamic Design ◽  
Gas Generator ◽  
Power Turbine ◽  
Calculation Results ◽  
Radial Equilibrium

Based on the aerodynamic design and development of a power turbine for an aircraft derivative marine gas turbine in our engineering practice and taking account of the specific features of a marinization effort, this paper describes the design approach and aerodynamic characteristics of the said power turbine, including parameter selection, design methodology, comparison of flow calculation results obtained by simple radial equilibrium and full radial equilibrium method, and a versatile design of the power turbine capable of rendering two power ratings. Also described is the use of variable geometry stator blades to accommodate a small amount of adjustment to the gas generator outlet parameters.

Study on Simplified Prediction Method of Thermal Ratchet Deformation Based on Parallel Bar Model

2014 ◽  
Author(s):  
Toshiaki Kokufuda ◽  
Naoto Kasahara
Keyword(s):  
Elevated Temperature ◽  
Inelastic Deformation ◽  
Evaluation Method ◽  
Failure Modes ◽  
Prediction Method ◽  
Inelastic Strain ◽  
Primary Stress ◽  
Redistribution Mechanism ◽  
Creep Fatigue ◽  
Calculation Results

For elevated temperature structures such as fast breeder reactor components, inelastic deformation is likely to occur because of reduction of yield stress and occurrence of creep deformation. The typical failure modes for elevated temperature structures are excessive deformation caused by the accumulation of inelastic deformation and creep fatigue caused by inelastic strain concentration at structure discontinuities. In order to prevent such failures, it is necessary to evaluate inelastic deformation adequately. Thermal ratchet deformation, namely the progressive plastic deformation induced by cyclic thermal stress with uniform primary stress, has some possibility resulting in excessive deformation. ASME boiler & pressure vessel code provides elastic evaluation methods for thermal ratchet. However, these methods are so focused on preventing thermal ratchet deformation, that it could be too conservative under some conditions. Therefore, a simplified elastic evaluation method to quantify thermal ratchet deformation is desired. In this paper, the simplified prediction method for thermal ratchet deformation is proposed using parallel bar model, which represents stress redistribution mechanism of cylindrical vessels. The solution of thermal ratchet deformation of parallel bar model was derived and compared with FEM calculation results of cylindrical vessels. This theoretical solution is proposed as a prediction method for thermal ratchet deformation of cylindrical vessels. The applicable area of the proposed prediction method is the cylindrical vessel under linear and parabolic temperature distribution through the wall thickness.

Study on Temperature and Stress Development of Channel Lining Concrete in Construction

2013 ◽  
Vol 724-725 ◽  
pp. 1731-1735
Author(s):  
Sheng Qiang ◽  
Ya Jing Bie ◽  
Hua Long Cai
Keyword(s):  
Joint Space ◽  
Concrete Lining ◽  
Engineering Practice ◽  
Tension Stress ◽  
Construction Period ◽  
Water Transportation ◽  
Transportation Channel ◽  
Calculation Results ◽  
North Water ◽  
Forward Engineering

Lining of water transportation channel needs high requirements of crack prevention. The tension stress which results from temperature and other factors during construction is an important reason that causes concrete cracks. Through the simulation of concrete lining during construction period with a section of the middle route of South-to-North Water Transfer Project, it is found that concrete pouring temperature, joint space, cutting joint time always make great contributions to lining crack. Based on calculation results some pertinence measures for temperature control and crack prevention are put forward. Engineering practice shows that effects of these measures are remarkable, which means these measures have significant reference to the concrete lining construction of the same type channels.

Predicts Based on Multi Modality Support Vector of the Settlement of Composite Foundation

2014 ◽  
Vol 919-921 ◽  
pp. 716-722
Author(s):  
Li Hua Zhang ◽  
Hai Bo Liu ◽  
Feng Ping An
Keyword(s):  
Support Vector Machine ◽  
Composite Foundation ◽  
Good Effect ◽  
Support Vector ◽  
Foundation Settlement ◽  
Modal Synthesis ◽  
Mode Decomposition ◽  
Calculation Results ◽  
The Stability ◽  
High Degree

Composite foundation settlement is affected by many factors, and settlement data is a non-linear changing process with complexity, suddenness and progressive nature and so on. So we must analyze and predict the stability of the foundation settlement. Because empirical mode decomposition (EMD) provides a new way for foundation settlement prediction, we can extract modal signals associated with the foundation settlement mechanisms by decomposing the monitoring data of settlement by EMD and use the support vector machine ( Support Vector Machine, SVM) modal to predict the obtained signal, Calculation results of the modal synthesis and accumulation of foundation settlement, get the evolution of Change with the time of foundation settlement. Combined with the engineering example for the application ,shows that the prediction model has good effect in multi modality support vector, a high degree of agreement with the monitoring values, indicating that this method has a promotional value.

Justification for Determination of the Depth of an Active Zone Based on the II Group of Limiting States

2014 ◽  
Vol 580-583 ◽  
pp. 98-104
Author(s):  
Lunara Maksotovna Nurumbayeva ◽  
Andrey Nikolaevich Badanin
Keyword(s):  
Experimental Data ◽  
Active Zone ◽  
Economic Benefits ◽  
Summation Method ◽  
Regulatory Framework ◽  
Foundation Settlement ◽  
The Core ◽  
Calculation Results ◽  
Optimum Width

The problems of the amendments in the updated edition of SNIP 2.02.01-83 * “Foundations of buildings and structures" SP 22.13330.2011 “Foundations of buildings and structures” are discussed in the article". Theoretically, the depth of the core is not justified anywhere and the restrictions are made only on the basis of experimental data. The importance of the amendments should be displayed theoretically. In according to the newly adopted regulatory framework the results of the foundation settlement calculations for the limited states of the second (II) group by the layer-stack summation method with the justification of the amendments in the updated edition of SNIP 2.02.01-83 * "Foundations of buildings and structures" SP 22.13330.2011 "Foundations of buildings and structures” are shown in this article. In the second part of the article the optimum width selection calculation results of projected foundation and identification of the economic benefits of decisions made are shown.

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