基于不同区域土体变形特性的自升式平台拔桩阻力计算方法研究  

Study of Calculation Method of Spudcan Uplift Resistance of Jackup Platform Based on Soil Deformation Characteristics in Different Regions

作　　者：贺林林[1,2] 赵陈雨 刘洋[3] 李志松 赵磊娜 HE Linlin;ZHAO Chenyu;LIU Yang;LI Zhisong;ZHAO Leina(Hohai College,Chongqing Jiaotong University,Chongqing 400074,China;National Engineering Research Center for Inland River Channel Regulation,Chongqing Jiaotong University,Chongqing 400074,China;Chongqing University of Science and Technology,Chongqing 401331,China)

机构地区：[1]重庆交通大学河海学院,重庆400074 [2]重庆交通大学国家内河航道整治工程技术研究中心,重庆400074 [3]重庆科技学院,重庆401331

出　　处：《中国造船》2023年第3期144-156,共13页Shipbuilding of China

基　　金：重庆市博士后科研项目特别资助项目(Xm2017188);重庆市基础与前沿研究科学基金(cstc2018jcyjAX0559);重庆交通大学研究生科研创新项目(2021S0028)。

摘　　要：为了研究自升式平台在饱和软黏土拔桩过程中所受拔桩阻力的大小及变化规律,基于不同区域土体的变形特性,应用ABAQUS软件分别采用耦合的欧拉-拉格朗日(CEL)数值分析方法与基于小应变理论的有限元(SSFE)计算方法建立了桩靴上部阻力与底部吸附力的数值计算模型;提出了自升式平台拔桩阻力计算方法,并与已有的离心机试验结果进行比较。根据不同固结条件,开展了土体不排水抗剪强度、贯入深度以及桩靴直径对桩靴拔桩阻力的敏感性分析。研究结果表明:该计算方法能有效预测桩靴在软黏土中所受的拔桩阻力,其中上部阻力、底部吸附力预测误差分别为14.48%和-7.25%~4.23%,峰值拔桩阻力预测值误差为15%左右;桩靴所受的上部阻力主要来自于上覆土体对桩靴的反作用力,而底部吸附力则由桩靴底部土体中负超孔隙水压力引起;上部阻力受上述3项因素影响较大,而底部吸附力则随着固结时间增加而显著增大。研究成果可为桩靴拔桩作业过程中的受力分析提供借鉴与参考。In order to study magnitude and variation law of the breakout force in the process of spudcan extracting during the jack-up platform operated in soft clay,numerical calculation models were established to simulate the variation of the top resistance and the base suction force of the spudcan employing ABAQUS together with coupled Eulerian-Lagrangian(CEL)method and small strain theory based-finite element(SSFE)method respectively.Calculation method of extraction resistance of the spudcan was put forward,which was verified by existing centrifuge tests.Sensitivity of three influencial factors including undrained shear strength,penetration depth and spudcan diameter were analyzed under different consolidation conditions.The results show that the method proposed herein can effectively calculate the variation of the resistance during spudcan extracting in the soft clay foundation.Prediction errors of the top resistance and base suction force are 14.48%and within-7.25%~4.23%respectively,and error of the overall breakout force is about 15%.Top resistance of the spudcan mainly results from the reaction force of the overlying soil,while the base suction force is induced by the negative excess pore pressure in the soil at the bottom of the spudcan.Top resistance is comparatively sensitive to these three factors,while the base suction force significantly increases with increase of consolidation time.Research results in this paper may provide a reference for analyzing and calculating the process of spudcan extracting.

关 键 词：自升式平台 拔桩阻力 土体变形特性 数值分析 敏感性分析 

分 类 号：TU473[建筑科学—结构工程]