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Pipeline Pull-Back Load Analysis by Continuous Beam Theory
Zhengwei Guo,Shuai Xie,Liancheng Ren,Chaoqun Dong,Yinchun Gong 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.4
Pipeline pull-back load is an important basis for selecting power and checking capability of drilling equipment. In this paper, mechanical models of the pipeline hoisting outside and pulling inside the hole are established by the continuous beam theory, and relationships among various parameters are analyzed in the process of pull-back pipeline. The results show that there is a linear relationship between the lifting height of basket and the entry angle of hole. During the construction of the hoisting pipeline, the bending moment and shearing force of the basket position near the hole are larger, so the strength check of the pipeline only needs to do at this position. There is a linear relationship between the lifting height of the basket and the length of spanning pipeline. The lifting load and axial force of the pipeline vary linearly. The pull-back load of the pipeline varies curve in the arc segment of the trajectory. The pipeline pull-back load varies linearly in linear segment of trajectory.
Analysis of the Pipeline Pull-back Load for Horizontal Directional Drilling
Zhengwei Guo,Zheng Liang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.12
One of the major areas of research in Horizontal Directional Drilling (HDD) technology is the accurate prediction of the pipeline pull-back load, which influences the project design schemes, selection of the drilling rig type and the mechanism of pull-back for reducing resistance. In this study, the possible contact state between the pipe and the hole is analysed based on the force exerted by the pipe in the circular sector of the hole, and the pull-back resistance of the pipe is calculated according to the bending beam theory. The full-scale model of the pipeline pull-back is established using numerical methods, the results of which are then compared to those obtained in the field test. In the numerical analysis, the resultant force of the mud buoyancy and pipeline gravity is substituted with an equivalent gravitational acceleration in the vertical direction. The results show that the pull-back force is not uniform when the pipe has just entered the hole. When the pull-back load is stabilised, the pull-back force of the pipeline is appropriately linear. After the pipe enters the hole, the variation curve of the pull-back force depends on the various values of the equivalent gravitation acceleration.
Zhengwei Luo,Lei Li,Mulin Guo,Hui Jiang,Wenhua Geng,Wuji Wei,Zhouyang Lian 한국섬유공학회 2020 Fibers and polymers Vol.21 No.12
In this work, a new strategy was developed to prepare Cr(VI)-imprinted polypropylene (PP) fibers-based materialsfor the adsorption of Cr(VI) from water. Granular PP was modified with dual monomers (glycidyl methacrylate (GMA) andacrylamide (AM)) by water-solid suspension grafting copolymerization. Then, this fibers morphology was obtained by meltblowing. Hence, the preparation steps of the fibrous Cr(VI)-imprinted adsorbent involved surface ion-imprinting andcrosslinking. The influence of the grafting conditions on the grafting percentage was investigated. The maxima graftingpercentages of GMA and AM were 16.4 and 10.6 %, respectively. The chemically modified products showed good mobilityand stability, thus meeting the requirements of melt-blowing method. The prepared Cr(VI)-imprinted polymers showed amaximum adsorption capacity to Cr(VI) of 43.2 mg/g at pH 3. The adsorption data were well fitted by the pseudo-secondorderand Langmuir adsorption models. The adsorbent showed good selectively toward Cr(VI) in a mixed solution containingCu(II) and SO42−. The X-ray photoelectron spectroscopy demonstrated that the adsorbed Cr(VI) was partly reduced to Cr(III).
Qu Zhengwei,Zhang Jianxuan,Wang Yunjing,Georgievitch Popov Maxim,Guo Kai 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.2
To solve the problem that the false data injection attack can evade the unfavorable data recognition mechanism and tamper with the state estimation, this paper proposes a detection and defense scheme for the fake data injecting attack based on the trust degree of the nodes. Considering the failure of the attacker’ s carefully constructed implicit data injection attack with residual threshold method, this paper proposes a node trust model and a trust update algorithm based on the characteristics of state estimation of power system nodes. Feasibility of detecting false data injection based on trustworthiness and using IEEE-14 and IEEEE-118 nodes to systematically analyze diff erent false information injection scenarios. Secondly, in order to eliminate the interference of the false data injected by the attacker to the normal operation of power network, this paper combines the process of trust updating algorithm with the classical weighted least square algorithm to improve the robustness of state estimation and to mitigate the infl uence of fake data injection attacks on power networks. In this paper, simulation experiments are carried out on 14 nodes and 118 nodes system to test the accuracy of the optimized state estimation algorithm
Tri-Axial Confining Numerical Test and Settlement Analysis of the Gravel Layer
Liang Zhang,Zhengwei Guo,Zheng Liang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.9
The discrete element method (DEM) is used according to the discreteness of the gravel layer to analysis the gravel particle. This paper presents simulations of tri-axial experiment tests and settlement of gravel layer. The stress-strain curves of gravel layer were analysed with different confining pressure through tri-axial numerical test, and the effect with different particle parameters and confining pressures was analysed. The numerical model of gravel layer after the excavation was established by the DEM to statistically analyse the settlement of gravel layer. The analyses results show that confining pressure corresponds to axial pressure that be destroyed of gravel particle model. The static friction coefficient has little effect on the failure of the tri-axial confining experimental model. The experiment model with various particle sizes need higher axial stress that be destroyed than the same particle size. During the collapse of the gravel stratum, the gravels are closer to the top of the hole which have a larger shift of settlement and a faster sedimentation rate. If the gravel are further away from top of the hole which have a smaller shift of settlement and slower sedimentation rate. The settlement of gravel causes the forces variation in all directions.