摘要
本项目抛石挤淤法填海场地地层极不均匀,存在粒径较大块石和淤泥区,自身固结沉降尚未完成,地下水位受潮汐影响显著,填土层渗透系数较大,超过100m/d。场地整体稳定性虽满足要求,但部分区段地基在楼体建造或场地不均匀填土过程中可能产生局部失稳问题。预制混凝土空心方桩在该地层中施工困难,桩端可能无法进入设计持力层,是部分建筑产生严重不均匀沉降并造成结构开裂破坏的主要原因。为加固设计提供依据,进行了有限空间内微型钢管桩施工工艺及静载试验。微型钢管桩直径200mm,以中风化岩层作为桩端持力层。结果表明潜孔钻机跟管钻进成孔工艺可行,微型钢管桩单桩承载力达到662kN,符合设计要求。桩基设计还需考虑负摩阻力的影响,扣除负摩阻力后单桩承载力特征值可取520kN。
The reclamation site formed by dumping rockfill for extruding silt in this article is extremely inhomogeneous,contains a lot of large-size block stones and silt in it,and self-consolidation settlement has not been completed yet.The groundwater level is significantly affected by the tide,and the permeability coefficient of the fill soil is over 100m/d.Although the overall stability of the site meets the requirement,but the foundation in some sections may instability during the building construction or the uneven filling of the site.Precast concrete piles are difficult to reach the designed position in this soil stratum,which is the main reason of some buildings occurred severe uneven settlement and caused structural cracking and damage.Experiment with the steel pipe pile construction technology and static load test in limited space,for provide basis for the foundation improvement design.The diameter of the steel pipe micorpile is 200mm,and the medium weathered rock layer is used as the supporting layer.The result shows that the construction process with down the hole drill is feasible,the single pile bearing capacity is 662k N,which can meet the design requirements.Negative skin friction also should be considered in the pile design.The advised characteristic value of single pile bearing capacity after deducting the negative skin friction is 520kN.
作者
冯彬
迟铃泉
李宁
朱肇京
FENG Bin;CHI Lingquan;LI Ning;ZHU Zhaojing(State Key Laboratory of Building Safety and Built Environment,Beijing 100013,China;China Academy of Building Research Foundation Institute,Beijing 100013,China;Beijing Engineering Technology Research Center of Foundation and City Underground Space Development and Utilization,Beijing 100013,China)
出处
《建筑结构》
CSCD
北大核心
2022年第S01期2183-2188,共6页
Building Structure
关键词
填海造地
固结
地基稳定性
微型钢管桩
承载力
负摩阻力
land reclamation
consolidation
foundation stability
steel pipe micropile
bearing capacity
negative skin friction
作者简介
第一作者:冯彬,硕士,工程师,注册土木工程师(岩土),Email:469244184@qq.com。
