基于低成本毫米级GNSS技术的膨胀土边坡现场监测

Field monitoring of expansive soil slope based on low-cost millimeter-sized GNSS technology

将高精度北斗/全球卫星导航系统(GNSS)监测技术引入到膨胀土滑坡监测中,并针对传统GNSS监测设备体积大、成本高和精度低的局限性,设计极简化监测模块和“共享电源”,研制出成本约2000元的GNSS膨胀土监测设备,其体积比传统设备体积缩小了近75%。其次,针对传统GNSS监测设备易受到环境干扰问题,提出一种高精度抗干扰的数据处理策略,实现了毫米级的实时监测精度。最后,以安康机场膨胀土边坡试验区为例,布设8个低成本GNSS设备进行实时监测。研究结果表明:本文所提技术在平面方向和高程方向上的实时(秒级)监测精度分别可达3.0 mm和4.5 mm,试验区监测位移和形变速率结果均能较准确地反映膨胀土滑坡形变的涨缩特征;降雨和相对湿度对GNSS形变结果具有滞后效应;低成本BDS/GNSS技术应用于膨胀土滑坡监测中是可行的。

Firstly,a high-precision BeiDou/global satellite navigation system(BDS/GNSS)monitoring technology was applied to the landslide monitoring of expansive soil.Aiming at the defects of the traditional GNSS monitoring equipment in terms of volume,cost and precision,a set of GNSS monitoring equipment with a cost of about ¥2000 was developed by simplifying the monitoring equipment module and adopting the idea of"sharing power supply",which is nearly 75%smaller than the traditional equipment.Secondly,aiming at the problem that traditional GNSS monitoring equipment is vulnerable to environmental interference,a high-precision antiinterference data processing method was proposed to achieve real-time millimeter monitoring accuracy.Finally,taking the expansive soil slope test area of Ankang Airport as a reference,8 sets of low-cost GNSS equipment were set up for real-time monitoring.The results show that the monitoring precision of the proposed technology is 3.0 mm in the plane direction,and it is 4.5 mm in the elevation direction.The results of monitoring displacement and deformation rate can accurately describe the swelling and shrinkage characteristics of expansive soil landslide.Rainfall and relative humidity factors have lag effect on the GNSS deformation results.The application of lowcost BDS/GNSS technology in expansive soil landslide monitoring is feasible.