阳光小区住宅楼桩基质量问题与加固设计研究  

Study on quality problems and reinforcement measures of pile foundation of a residential building at Yangguang District

作　　者：肖俊华[1,2] 孙剑平[1,2] 

机构地区：[1]山东建筑大学土木工程学院,山东济南250101 [2]山东建大工程鉴定加固研究所,山东济南250013

出　　处：《山东建筑大学学报》2015年第6期537-543,共7页Journal of Shandong Jianzhu University

基　　金：长江学者和创新团队发展计划资助项目(IRT13075)

摘　　要：沉管灌注桩的质量问题的分析与研究是地基加固设计的前提,加固设计方案优化可节省工程造价。文章针对阳光小区11层高层住宅楼的沉管灌注承载力未达设计要求的质量问题,从工程地质条件、桩型传力机理、现场施工工艺等方面分析了桩基承载力偏低的原因;利用复合减沉疏桩基础的概念进行加固设计优化,并采用Pile软件对桩基沉降进行了分析计算。结果表明:阳光小区住宅楼场地桩长范围内存在可塑—软塑黏土层,选定桩型传力机理不清,当地施工能力难以达到设计要求是沉管灌注承载力未达标的主要原因;加固方案若不考虑桩间土的分担作用,基桩发挥极限承载力的65%即可承担上部荷载;当考虑桩间土承担10%的上部荷载时,基桩发挥极限承载力的58.6%,预计工程最终沉降在15 mm以内;从承载力和沉降控制两个方面考虑,加固后桩基工程有足够的安全度。The research on quality problem of cast-in-place pile by sinking tube is the basis of foundation reinforcement design, and optimized reinforcement design scheme can save the engineering cost. An 11-storied high-rise residential building located at Yangguang District is founded on cast-insitu pile by sinking tube. However, the testing result shows that pile capacity couldn＇t meet the design requirement. Aimed at such quality problem, some factors are studied such as geological conditions, bearing mechanism of the designed pile type and construction technology. To optimize the reinforcement design, the concept of composite foundation with settlement-reducing piles is introduced for adding pile; meanwhile pile foundation settlement is predicted with pile software. Analysis and calculation results show： （ 1 ） pile quality problems are caused by existence of plastic to soft-plastic clay at the pile length scope, unsuitable pile type and defectively constructing technique; （2） for optimized reinforcement design, neglecting the load-sharing between soil and pile, 65% of ultimate bearing capacity of pile is enough to resist upper load while assuming soil taking 10% of total upper load, 58.6% is enough; （3） the final settlement is predicted in 15mm; （4） from two aspects of bearing eaoacitv and settlement control, the pile foundation engineering has margin of security.

关 键 词：质量问题 加固设计 沉管灌注桩 桩基承载力 复合减沉疏桩 

分 类 号：TU974[建筑科学—建筑技术科学]