花岗岩地层灌注桩抗拔承载性能研究  

Study on uplift bearing capacity of cast-in-situ piles in granite geological stratum

作　　者：程华群 CHENG Hua-qun(Shenzhen Capol International&Associates Co.,Ltd.,518038,Shenzhen,Guangdong,China)

机构地区：[1]深圳市华阳国际工程设计股份有限公司,广州518038

出　　处：《建筑技术》2024年第15期1820-1824,共5页Architecture Technology

摘　　要：对深圳地区花岗岩地层进行了4组有无后注浆试验桩抗拔静载试验对比研究。结果表明,泥浆护壁成孔灌注桩桩侧泥皮效应不仅在土层存在,在微风化岩层也会存在,泥皮会削弱抗拔桩侧阻力;当桩侧无后注浆时,抗拔极限承载力较低,桩顶上拔量较大,并具有较大离散性;桩侧后注浆可解决泥皮效应,大幅提升抗拔极限承载力;同组对比试验的无后注浆与有后注浆抗拔桩的轴力传递与侧阻力分布规律相似,而长度较短的嵌岩桩和中长桩侧阻力分布规律不同;按我国有关标准经验公式计算的无后注浆灌注桩抗拔极限承载力结果被高估。A comparative study on the static load test of four groups of cast-in-situ piles with and without post-grouting on the side in granite geological in Shenzhen was carried out.The results show that the mud skin effect exits not only in the soil layer,but also in the slightly weathered rock layer,which will weaken the shaft resistance.The uplift ultimate bearing capacity is lower,the displacement at top of the pile is larger,and dispersion is greater,if there is no post-grouting on the side of pile.The post-grouting on the side of pile can solve the mud skin effect,which can enhance the uplift ultimate bearing capacity significantly.The axial force transmission characteristic and shaft resistance distribution of uplift piles in same group with and without post grouting are similar.The shaft resistance distribution of short rock-socketed pile is different from that of medium-long pile.The calculation result base on empirical formula in relevant Chinese standards for the uplift ultimate bearing capacity of cast-in-situ pile without post-grouting on side is overestimated.

关 键 词：抗拔桩 抗拔极限承载力 泥皮 后注浆 静载试验 

分 类 号：TU473.1[建筑科学—结构工程]