大直径灌注桩的分级扩孔旋挖钻头导向能力分析  

STUDY ON THE GUIDING ABILITY OF ROTARY DIGGING BITS FOR GRADED REAMING N LARGE DIAMETER CAST-IN-PLACE PILE

作　　者：谭松娥 方小红[2] 杨勇 陈刚 韩强 TAN Song-e;FANG Xiao-hong;YANG Yong;CHEN Gang;HAN Qiang(Central-south Architectural Design Institute Co,Ltd,430071,Wuhan China;Faculty of Engineering.China University of Geoscences,430074,Wuhan,China)

机构地区：[1]中南建筑设计院股份有限公司,武汉430071 [2]中国地质大学(武汉)工程学院,武汉430074

出　　处：《建筑技术》2025年第2期215-219,共5页Architecture Technology

摘　　要：在基岩中进行大直径旋挖灌注桩施工时,受钻机能力的限制常采用分级扩孔钻进的方法。但当分级钻头直径小于设计桩径时易发生钻孔偏斜,而带上、下扶正装置的分级扩孔旋挖钻头可起到较好的防斜效果。为了对不同结构形式的分级扩孔旋挖钻头的防斜原理和导向能力进行评价,研究对不同组合形式的旋挖钻具进行了理论受力分析,并应用SolidWorks软件中的仿真插件对旋挖钻具进行了静力学分析。仿真分析过程中,以旋挖钻头切削破岩端面的最大侧向位移量来评价钻头的导向能力,位移越小则导向能力越强,反之亦然。结果表明,分级扩孔旋挖钻头结构形式对其导向能力影响显著,上、下扶正装置可显著降低旋挖钻头的最大侧向位移,但同时增加旋挖钻杆的侧向变形量;无扶正装置时,旋挖钻头侧向位移量受桩孔深度、钻压和扭矩的影响显著,而增加上、下扶正装置后,上述影响会变的不显著。When rotary digging is applied in large diameter cast-in-place piles construction in bedrocks,the graded reaming method is often used due to the limitation of the drilling rig’s capacity.However,if the diameter of the graded rotary digging bits are smaller than the designed pile diameter,the drilled borehole will be deviated,while engineering practices indicate that the inclination can be prevented if the reaming bits are coupled with upper,or lower centralizing devices.In order to study the inclining prevention mechanism and evaluate the guiding ability of graded reaming bits with different structures,the force state of the rotary drilling strings with different bits are theoretically analyzed at first,and then its static states are numerically analyzed by the simulation module of SolidWorks.In the simulation process,the maximum lateral displacement of the bottom surface of the rotary digging bit was used to evaluate the guiding ability of the bits,and the smaller the displacement,the stronger the guiding ability,and vice versa.The results show that the structural form of the graded rotary digging bits has a significant effect on its guiding ability,and the upper and lower centralizing devices can remarkably reduce the maximum lateral displacement of the rotary digging bits,but at the same time increase the lateral deformation of the rotary drilling pipe.When there is no centralizing device,the lateral displacement of the graded rotary digging bit is significantly affected by the pile depth,drilling pressure and torque,but the above mentioned influences will become insignificant after the additions of the upper and lower centralizing devices.

关 键 词：大直径灌注桩 分级扩孔 旋挖钻头 扶正装置 

分 类 号：TU473.14[建筑科学—结构工程]