冻土区桩基温度场分析及温度应力控制研究  

Study on temperature field analysis and temperature stress control of pile foundation in permafrost area

作　　者：詹钦鹏 王飒 向敏 郭吉成 吴多 ZHAN Qinpeng;WANG Sa;XIANG Min;GUO Jicheng;WU Duo(School of Civil Engineering,Shijiazhuang Tiedao University,Shijiazhuang 050043,China;Dezhou City Lingcheng District Housing and Urban-Rural Development Bureau,Dezhou 253599,China;School of Civil and Architectural Engineering,Nanchang Institute of Technology,Nanchang 330099,China)

机构地区：[1]石家庄铁道大学土木工程学院,河北石家庄050043 [2]德州市陵城区住房和城乡建设局,山东德州253599 [3]南昌工程学院土木与建筑工程学院,江西南昌330099

出　　处：《甘肃科学学报》2024年第4期48-53,共6页Journal of Gansu Sciences

基　　金：江西省教育厅科学技术研究项目(GJJ190980);石家庄铁道大学2023年度研究生创新资助项目(YC202306)。

摘　　要：以传热学为基础,结合川藏铁路沿线冻土区某桥梁工程实例,确定边界条件与模型计算热力学参数。通过有限元软件建立三维数值模型分析求解,绝热温升的数值模拟计算值与公式理论计算值相吻合,研究了低温环境下桩基浇筑完成后桩土温度场的演化规律,分析并探究了温度应力的成因及其控制措施,以改善桩基的工作性能。结果表明:在混凝土浇筑完成前期,受水泥水化热的影响,桩中心温度明显高于同一深度桩壁温度,桩内外温度差引起温度应力,即在桩表面出现拉应力、桩中心出现压应力;但地面以上桩基部分出现了拉应力大于混凝土允许抗拉强度的状况,为此在桩顶处设置5 d、1℃的保温措施,温度应力明显改善,有效防止了桩基冻裂发生。研究成果可为类似工程设计及施工提供借鉴。Based on the heat transfer theory,combined with the bridge engineering example of a frozen soil area along the Sichuan-Tibet railway,the boundary conditions and the thermodynamic parameters of the model calculation were determined.A three-dimensional numerical model was established by finite element software for analysis and solution.The numerical simulation value of adiabatic temperature rise was consistent with the formula theoretical calculation value.The evolution law of pile-soil temperature field after pile foundation pouring in low temperature environment was studied and the causes and control measures of temperature stress were analyzed and explored to improve the working performance of pile foundation.The results show that the temperature of pile center was obviously higher than that of pile wall at the same depth in the early stage of concrete pouring.Due to temperature difference between inside and outside the pile,there existed temperature stress,that is,tensile stress on the pile surface and compressive stress in the pile center.However,the tensile stress of pile foundation above the ground was greater than the allowable tensile strength of concrete.Therefore,heat preservation measures of 5 d and 1℃were set at the top of pile,the temperature stress was significantly improved,which effectively prevented the freezing crack of pile foundation.The results can provide reference for similar engineering design and construction.

关 键 词：多年冻土区 钻孔灌注桩 水泥水化热 桩基温度场 温度应力 

分 类 号：TU473.1[建筑科学—结构工程]