摘要
结合工程实例,介绍了广州南沙区深厚软土地质下的地基处理方法、桩基础设计计算过程,提出了软土地质条件下超长灌注桩的设计、施工控制措施。现场试验表明:含水率大、孔隙率大的淤泥硬化处理宜采用高压旋喷法。计算分析显示:负摩阻力计算的中性点深度可结合负摩阻力产生的具体原因综合确定;存在负摩阻力的桩基,静载试验最大加载值直接采用单桩承载力特征值的2倍未如实反应桩基受力,结果偏不安全,应另加上负摩阻力的2倍。灌注桩长大于60 m时,水下成孔、成桩质量难度加大,为保证单桩承载力满足设计要求,宜采用桩端后注浆工艺,同时应制订施工关键节点的控制措施,加强过程监管。
Based on a real engineering,the ground improvement and pile foundation methods are introduced in the deep and thick soft soils in Nansha District,Guangzhou City.Some construction control measures are represented for the over-long filling pile.The site trials show:jet grouting method is more suitable to stabilize sewer sludge with large water content and porosity.Computational analysis shows that the mid-point depth of negative pile friction can be determined according to causes of it.The max load in the pile static loading testing does not reflect the real loading of the piles if only calculated by doubling the characteristic value of the bearing capacity,and the test may be unsafe too,it should be also added by doubling the negative pile friction.When the pile is over 60 m long,the hole drilling and pile forming becomes more difficult.In order to confirm the pile bearing capacity,post-grouting technique is recommended,some control measures should be established for the key construction joints and the processing supervision should be strengthened.
作者
张全林
ZHANG Quanlin(Guangzhou Architectural Engineering Design Institute Co.,Ltd.Guangzhou 510030,China)
出处
《广东土木与建筑》
2021年第11期62-65,共4页
Guangdong Architecture Civil Engineering
关键词
深厚软土
超长灌注桩
负摩阻力
施工控制
deep and thick soft soils
over-long filling pile
negative pile friction
construction control
