冲孔桩关乎成孔效率上限的提钻高度计算  

Calculation of Bit Lifting Height of Punching Pile Related to Upper Limit of Hole Forming Efficiency

作　　者：范旭红[1] 薛颖楠 杨帆[1] 任冠宇 FAN Xuhong;XUE Yingnan;YANG Fan;REN Guanyu(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang,China,212013;China 20th Metallurgical Group Co.Ltd.,Shanghai,China,201900)

机构地区：[1]江苏大学土木工程与力学学院,江苏镇江212013 [2]中国二十冶集团有限公司,上海201900

出　　处：《沈阳建筑大学学报（自然科学版）》2021年第4期650-658,共9页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金面上项目(51978315)。

摘　　要：目的冲孔桩在孔壁稳定前提下的成孔效率与提钻高度牢不可分,找到单次冲击锤头的最佳提钻高度,为成孔效率上限计算提供依据。方法利用有限元软件ABAQUS模拟锤头在泥浆中下落,探究锤头质量、泄浆孔半径、泥浆黏度、泥浆相对密度对锤头运动速度的影响规律。结果锤头在泥浆中自由下落约0.5 s即达到最大速度,对应高度约1 m;利用MATLAB的最小二乘法得到最佳提钻高度表达式为H=0.4467+0.0337 X_(m)-5.6677 X_(d)+21.2329 X^(2)_(d)-0.2363 X_(w)。结论锤头在泥浆中自由下落不超过1m(具体数值由参数确定)即可达到收尾速度,之后立刻触底,可实现最短速度内达到最大冲击功,从而实现成孔效率最大化。The hole forming efficiency of the punching pile under the premise of the stability of the hole wall is closely related to the drilling height.Finding the best drilling height for a single impact provides a basis for the calculation of the upper limit of hole forming efficiency.The method is to use the finite element software ABAQUS to simulate the hammer head falling in the mud,so that explore the influence of hammer quality,slurry discharge hole radius,slurry viscosity and slurry gravity on the speed of the hammer head.The result is that the hammer head will freely fall in the mud for about 0.5 s to reach the maximum speed,corresponding to a height of about 1m;Using the least square method of MATLAB,the expression of the optimal lifting height is obtained as follows:H=0.4467+0.0337 X_(m)-5.6677 X_(d)+21.2329 X^(2)_(d)-0.2363 X_(w).The conclusion is that the hammer head can reach the finishing speed when the hammer head falls freely in the mud within 1m(the specific value is determined by the parameter),and then touch the bottom immediately,which can achieve the maximum impact energy within the shortest speed,thereby maximizing the hole forming efficiency.

关 键 词：冲击成孔 成孔效率上限 收尾速度 ABAQUS 提钻高度 

分 类 号：TU391[建筑科学—结构工程]