基于北斗三号远程监测系统的公路岩质边坡开挖变形分析

Analysis of Excavation Deformation of Highway Rock Slope Based on BeiDou-3 Remote Monitoring System

为确保G336神木段匝道岩质边坡开挖安全,设计并采用了北斗三号(BeiDou-3 navigation satellite system,BDS-3)远程监测系统对边坡开挖进行实时监测。该监测系统由数据采集与传输子系统、BDS数据解算子系统及数据发布管理子系统构成,能实现实时远程自动化变形监测。边坡开挖模拟发现:边坡岩土体水平与竖向累计位移均小于5 mm,日位移均小于3 mm,为保证施工安全,将累计位移预警值和日位移预警值分别设为4 mm与2 mm。位移监测发现:开挖过程中,边坡岩土体的竖向位移大于水平位移,能够率先反映边坡位移状态和变化趋势,因此,开挖过程中应重点关注边坡竖向位移以保证施工安全。采用强度折减法进行边坡稳定性分析时,可利用边坡岩土体位移突变来判断边坡是否稳定,模拟发现坡脚处不存在位移突变特征,因此监测点应尽量选取边坡中上部或者塑性带附近。

To ensure the safety of the rock slope excavation of the G336 Shenmu section ramp,a remote monitoring system based on BeiDou-3 navigation satellite system(BDS-3)was designed and used to monitor the slope in real time.The monitoring system can realize real-time remote automatic deformation monitoring,which is composed of data acquisition and transmission subsystem,BDS data calculation subsystem and data release management subsystem.Through slope excavation simulation,it is found that the cumulative horizontal and cumulative vertical displacement of the slope rock and soil are both less than 5 mm,and the daily variation of the displacement is less than 3 mm.For construction safety,the cumulative deformation warning value and the daily deformation warning value are set as 4 mm and 2 mm respectively.By monitoring the deformation of the excavation process,it is found that more changes are indicated in the vertical displacement of the rock and soil of the slope than the horizontal displacement.The vertical displacement can firstly reflect the state and trend of the displacement of the slope.Therefore,more attention should be paid to the vertical displacement,in order to ensure construction safety.The sudden change of slope soil displacement can be used to judge whether the slope is stable,when strength reduction method is used to analyze slope stability.However,no sudden displacement feature is shown at the slope foot,the monitoring point should be selected in the upper part of the slope or near the plastic belt,as far as possible.