Engineering Characteristics and Reinforcement Program of Inclined Pre−stressed Concrete Pipe Piles

De-quan Zhou,Chen-xi Feng 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.9

When it comes to the deep soft soil foundation, improper construction, preloading, and excavation may result in the inclination of the pre−stressed concrete pipe (PCP) piles. Lack of understanding on deformation characteristics may lead to inaccurate reinforcement plan, thereby causing new engineering accidents. This study analyzes an engineering accident induced by the pile inclination, based on which the finite element method model is built. Deformation characteristics of the foundation incorporating inclined PCP piles are investigated, and the reinforcement program involving placement of the pile with opposite inclination is proposed and compared with the conventional reinforcement program using vertical piles. Findings of this study are two−folds: 1) A critical inclination angle affecting the vertical settlement exists, below which the pile inclination has limited effects upon the vertical load bearing capacity of the foundation. 2) The vertical subsidence, the lateral displacement and the bending moment of the reinforcement program based on the reversely inclined pile are all decreased, which helps bear the overburden load and improve stability. In the process of engineering accident treatment, the bearing capacity of PCP piles with small inclination angles can be first reduced according to their inclination angles, followed by judgement that whether these PCP piles meet the requirements on bearing capacity. The PCP piles with large inclination angles must be strengthened, and the reverse inclined PCP piles are recommended.

Experience of Congenital Choledochal Cyst in Adults:Treatment, Surgical Procedures and Clinical Outcome in the Second Affiliated Hospital of Harbin Medical University

De Quan Wu,Qiu Shi Wang,Hong Bo Jia,Hong Shang,Xiang Yu Zhong,Wen Xue Zhou,Zhen Hua Sun,Long Xian Zheng 대한의학회 2004 Journal of Korean medical science Vol.19 No.6

Nano La2O3 as a heterogeneous catalyst for biodiesel synthesis by transesterification of Jatropha curcas L. oil

Quan Zhou,Song Yang,Heng Zhang,Fei Chang,Hu Li,Hu Pan,Wei Xue,De-Yu Hu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.31 No.-

A comparative study on the activity of La2O3 and two kinds of nano La2O3 catalysts prepared usingsonochemical (nano La2O3-S) and hydrothermal methods in the transesterification to produce biodieselwas conducted. The relatively high activity of nano La2O3 catalysts may be ascribed to their high basestrength, large base amount, small particle size and large BET surface areas. Nano La2O3-S was selectedfor further optimisation due to its simple preparation procedure and short preparation time. The FAMEcontent and yield obtained were successively 97.6% and 90.3% under optimal conditions. Moreover, nanoLa2O3-S showed a remarkable tolerance to FFA.

CFD computation of ship motions and added resistance for a high speed trimaran in regular head waves

Wu, Cheng-Sheng,Zhou, De-Cai,Gao, Lei,Miao, Quan-Ming The Society of Naval Architects of Korea 2011 International Journal of Naval Architecture and Oc Vol.3 No.1

Some research work on CFD computation of ship motions and added resistance in waves for a high speed trimaran is carried out in this paper. The governing equations, Reynolds Averaged Navier-Stokes and continuity equations are discretized by finite volume method. Volume of fluid method is adopted to deal with the nonlinear free surface. The incident waves are generated from the inflow boundary by prescribing a velocity profile resembling flexible flap wavemaker motions, and the outgoing waves are dissipated inside an artificial damping zone located at the rear part of the wave tank. In this paper, the computed results of ship motion and added resistance for a high speed trimaran are presented. The results of seakeeping experiment for the high speed trimaran carried out in CSSRC towing tank are also presented in this paper. Rather good agreements are shown between the computational and experimental results. The work in this paper provides a numerical tool for the study of seakeeping performance of high speed trimarans.

Sensor-less external force detection for industrial manipulators to facilitate physical human-robot interaction

Bitao Yao,Zu-De Zhou,Lihui Wang,Wenjun Xu,Quan Liu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.10

Sensor-less external force detection is important for industrial robots which are usually not equipped with external force sensors to be applied in physical human-robot interaction (pHRI). This paper adopts the dynamic models of the robot in both dynamic mode and quasistatic mode to detect the external force. In the dynamic mode, the inertia and friction parameters of the robot are identified with the weighted least squares. The excitation trajectory for parameter identification is optimised. The un-modelled peak points in the joint torque residual are removed by a statistical method. The torque changes of joints in quasi-static mode which are equivalent to the joint pre-sliding friction is modelled with a lumped parameter model, generalised Maxwell slip (GMS) element model. Therefore, there is no need for the switching between the friction models in different modes and this and facilitates the application of dynamic model in the external force detection. The dynamic models of robots both in dynamic mode and quasi-static mode and their effectiveness for external force detection in pHRI are verified by experimental results.

CFD computation of ship motions and added resistance for a high speed trimaran in regular head waves

Cheng-sheng Wu,De-cai Zhou,Lei Gao,Quan-ming Miao 대한조선학회 2011 International Journal of Naval Architecture and Oc Vol.3 No.1

Some research work on CFD computation of ship motions and added resistance in waves for a high speed trimaran is carried out in this paper. The governing equations, Reynolds Averaged Navier-Stokes and continuity equations are discretized by finite volume method. Volume of fluid method is adopted to deal with the nonlinear free surface. The incident waves are generated from the inflow boundary by prescribing a velocity profile resembling flexible flap wavemaker motions, and the outgoing waves are dissipated inside an artificial damping zone located at the rear part of the wave tank. In this paper, the computed results of ship motion and added resistance for a high speed trimaran are presented. The results of seakeeping experiment for the high speed trimaran carried out in CSSRC towing tank are also presented in this paper. Rather good agreements are shown between the computational and experimental results. The work in this paper provides a numerical tool for the study of seakeeping performance of high speed trimarans.

Experimental Study of Mechanical Behavior of Passive Loaded Piles Adjacent to Piled Foundation

Yu Xie,Shao-he Zhang,De-quan Zhou 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

For combined piled foundation, passive loaded piles will be subjected to horizontal force when piled foundation is loaded, and horizontal force may cause the piles horizontal displacement, instability or even failure. With inclined bedrock nearby, the mechanical behavior of passive loaded piles will be more complex. In order to study the mechanical behavior of passive loaded piles under such condition, laboratory model test was carried out, during repeatedly loading/unloading cycles. Axial force, side friction, bending moment, and lateral soil pressure were analyzed. The study is based on model test, and more related studies are needed before being applied to practical conditions. The results show as follows: Axial force distribution of the piles changes with the increase of load and becomes stable under high load. This phenomenon is related to the expansion of potential slip surface in piled foundation. The passive loaded pile that is close to load boundary has only one neutral point which is located in the lower part of the pile, and its side friction has a relatively stable direction. On the contrary, the direction of side friction of the pile that is far from load boundary changes frequently. Bending moment curves of passive loaded piles vary with the change of the distance between the piles and load boundary, and they intersect at the lower part of the pile. Bending moment is basically negative above the intersection and gradually turns into positive below it. The maximum lateral soil pressure of passive loaded pile is triple that of the adjacent soil, indicating that passive loaded pile can effectively limit the horizontal deformation of piled foundation. But when the pile is too far from load boundary, it will lose the ability to limit the horizontal deformation of piled foundation.