广东地区花岗岩风化地基泥浆护壁灌注桩侧阻力取值探讨  

Discussion on the Value of Side Resistance of Cast-in-place Piles with Slurry Retaining Wall for Weathered Granite Foundation in Guangdong Province

作　　者：周宏 陈亮 Zhou Hong;Chen Liang(East China Electric Power Design Institute Co.,Ltd.of China Power Engineering Consulting Group)

机构地区：[1]中国电力工程顾问集团华东电力设计院有限公司,上海市200331

出　　处：《勘察科学技术》2024年第S1期94-97,共4页Site Investigation Science and Technology

摘　　要：广东地区花岗岩类的风化岩和残积土分布广泛,工程实践中常出现此类地层中泥浆护壁灌注桩竖向承载力偏低的情况,广东省地方标准认为是花岗岩风化岩土易软化、崩解的特性引起桩侧泥皮增厚,导致桩侧摩阻力降低,故规定泥浆护壁灌注桩的侧阻力需参照软塑黏性土进行取值,较国标桩基规范的建议值有大幅折减。而深圳某燃机电厂的现场试桩结果表明,通过实际试验测得的花岗岩风化岩土层中泥浆护壁灌注桩的侧阻力未有明显减小,此种情况并非特例,灌注桩承载力偏低的原因更有可能是桩端沉渣偏厚引起,若完全按广东省地方标准进行桩基工程设计,会偏于保守,造成不必要的浪费,建议实际应用时可予以适当提高。Granite weathered rock and residual soil are widely distributed in Guangdong.It is common to encounter low vertical bearing capacity of cast-in-place piles with slurry retaining wall in such strata in engineering practice.The local standards of Guangdong Province consider that granite weathered rock and soil are prone to softening and disintegration,leading the mud surface on the side of the pile to thicken,resulting in a reduction in pile side friction.Therefore,it is stipulated that the side resistance of cast-in-place pile with the slurry retaining wall must be determined with reference to the soft plastic clay soil,which is significantly reduced the recommended value compared to the international standard pile foundation specification.However,the on-site pile test results of a gas turbine power plant in Shenzhen show that the side resistance of wall cast-in-place piles with the slurry retaining in the granite weathered rock and soil layer measured through actual tests has not been significantly reduced.This situation is not an exception,and the reason for lower bearing capacity may be excessive sedimentation at pile ends.If the pile foundation engineering design strictly follows the local standards of Guangdong Province,it will be conservative and cause unnecessary waste.It is recommended that it can be appropriately increased in actual applications.

关 键 词：花岗岩 风化地基 泥浆护壁灌注桩 桩侧阻力 广东省地方标准 

分 类 号：TU473.1[建筑科学—结构工程]