基于自平衡法地质破碎带桩基承载能力研究  

Research on Bearing Capacity of Pile Foundation in Geologic Fracture Zone Based on Self-Balanced Load Method

作　　者：徐文冰 李小伟 赵军 罗航[1] 陈洪朋 Xu Wenbing;Li Xiaowei;Zhao Jun;Luo Hang;Chen Hongpeng(CCCC Second Harbor Engineering Co.,Ltd.,Wuhan Hubei 430014,China;Hubei Communications Investment Group Co.,Ltd.,Wuhan Hubei 430050,China)

机构地区：[1]中交第二航务工程局有限公司,湖北武汉430014 [2]湖北交通投资集团有限公司,湖北武汉430050

出　　处：《港口航道与近海工程》2023年第6期40-44,共5页Port,Waterway and Offshore Engineering

摘　　要：以鄂黄第二过江通道(燕矶长江大桥)为工程背景,基于桩基自平衡荷载试验,根据地质破碎带地层情况,研究自平衡试验的荷载布置、加载方式以及受力情况,获取地质断层破碎带区域桩基承载能力,并探究在各级荷载作用下各桩截面轴力、摩阻力随荷载和深度变化情况。结果表明,直径2.5 m桩长80 m的钻孔灌注桩采用旋挖钻成孔,导管法水下混凝土灌注施工工艺的可行性;桩身轴力、位移以及各截面摩阻力均与加载荷载呈类似线性变化规律,符合常规的Q-S曲线特性;地质破碎带的桩基承载能力完全满足设计要求,侧摩阻力与桩端承力占比分别为87.74%及12.26%,其承载能力以侧摩阻力为主,地质断裂破碎层导致岩层破碎分布不均及岩性变化(桩底糜棱岩层承载能力较低)对桩基承载能力造成较大影响。Based on the second river-crossing passage of Ezhou-Huanggang(Yanji Yangtze River Bridge),self-balanced load test of pile foundation are combined with the strata detail in geological fracture zone to study the load layout,load mode and stress,obtain the bearing capacity of pile foundation in geological fracture zone,and investigate the changes in axial force and friction resistance acting on each pile section under different loads and depths.The results verify the rotary digging technology applying to bore hole cast-in-situ piles 80 m in length and 2.5 m in diameter;the feasibility of underwater duct-based concreting technology;the pile’s axial force,deviation and the friction resistance on each pile section changing linearly with loads;Q-S curve conforming to rules;the bearing capacity of pile foundation in geological fracture zone meeting the design requirements completely;The bearing capacity and side friction resistance accounting for 87.74%and 12.26%respectively;the bearing capacity being given priority to side friction.Geological fracture layer leads to uneven distribution of broken rock stratum and the change of lithological character,namely,lower bearing capacity of mylonite at the bottom of pile,which has large effect on the bearing capacity of pile foundation.

关 键 词：自平衡试验 地质破碎带 桩基 承载能力 

分 类 号：U445[建筑科学—桥梁与隧道工程]