降雨下桥墩堆积体稳定性自动化监测研究及应用

Study and Application of Automated Monitoring Accumulation Stability at of Bridge Pier Under Rainfall

为研究降雨条件下广汕高速铁路(广州—汕尾)斧头石特大桥富水堆积体地层及桥墩的稳定性问题,开展一体自动化监测技术研究,分析施工及施工后18个月内土体变形沉降、孔隙水压力、降雨量、地表水位的变化,探讨降雨下堆积体地层及桥墩的位移规律。结果表明:桥墩对边坡上部堆积体地层位移起到了抑制作用,其左侧地层产生挤压,局部地表隆起后趋于稳定;监测段在第6—第11月内存在间歇性强降雨天气,改变了堆积体地层的蠕动变形模式,影响了地层对桥桩的侧向作用力,桥桩左侧承台因此发生偏移,但在顶部桥梁和底部稳定性地层的约束作用下恢复至稳定状态;在监测期内工程现场未发生堆积体边坡及桥墩失稳现象,综合地表沉降、深层位移、桥墩沉降数据分析,地层和桥梁均处于稳定状态。

In order to study the stability of the water rich accumulation strata and bridge piers of the Futoushi extra large bridge on the Guangzhou-Shanwei high speed railway under rainfall conditions,an integrated automated monitoring technology was conducted.The deformation and settlement of the soil,pore water pressure,rainfall,and changes in surface water level within 18 months after construction were analyzed,and the displacement laws of the accumulation strata and bridge piers under rainfall were explored.The results show that the bridge piers have a restraining effect on the displacement of the upper accumulation strata on the slope,causing compression in the left strata and stabilizing after local surface uplift.The monitoring section experienced intermittent heavy rainfall from the 6th to the 11th month,which changed the creep deformation mode of the accumulation strata and affected the lateral force of the strata on the bridge piles.As a result,the left bearing platform of the bridge piles shifted,but it returned to a stable state under the constraint of the top bridge and the bottom stable strata.During the monitoring period,there was no instability of accumulated slopes or bridge piers on the construction site.Based on comprehensive analysis of surface settlement,deep displacement,and bridge pier settlement data,both the strata and the bridge are in a stable state.