无支撑前斜后直倾斜双排桩支护监测与分析

Monitoring and Analysis of Inclined Double Row Piles Without Support

采用自动化实时监测系统平台进行"前斜后直"无支护倾斜桩支护结构内力和位移监测,经有限元数值计算,对比计算值与实测值结果,为基坑施工提供技术支撑和安全保障,同时探讨倾斜桩支护结构特性。结果表明:监测位移量相比计算值略大,"前斜后直"倾斜双排桩桩身最大位移总体发生在桩顶向下的位置,倾斜桩表现出一定斜撑效应,并随开挖深度的加深更加明显;监测及计算表明,直桩与倾斜桩桩身弯矩由桩顶先增大再减小,且上部弯矩与下部弯矩相反,斜桩弯矩总体大于直桩弯矩;当基坑挖深超过8m时,计算与实测结果显示,支护体系内力及位移对挖深更敏感,容易产生突增现象。

The automatic real-time monitoring system platform is used to monitor the internal force and displacement of the inclined double row piles.After the finite element numerical calculation, the calculated value and the measured value are compared.It provides technical support and safety guarantee for foundation excavation construction.At the same time,the characteristics of inclined pile supporting structure are discussed.The results show that the monitored displacement is slightly larger than the calculated value,and the maximum displacement of " forward and back straight" inclined double row piles generally occurs at the downward position of pile top.The inclined pile shows a certain effect of bracing,which becomes more obvious with the deepening of excavation.The results of monitoring and calculation show that the bending moment of straight pile and inclined pile first increases and then decreases from pile top,and the bending moment of upper pile is opposite to that of lower pile,and the bending moment of inclined pile is generally greater than that of straight pile.When the excavation depth of foundation excavation exceeds 8 m,calculation and actual measurement show that the internal force and displacement of the support system are more sensitive to the excavation depth.