深挖方膨胀土边坡伞形锚加固处理及效果监测

Slope Anchor Umbrella Strengthening Treatment and Monitoring the Effect of Deep Excavation Expansion

深挖方膨胀土边坡某段在雨季后坡脚出现隆起,排水沟局部发生挤压,并伴有断续性次生裂缝;监测成果也显示"区段边坡四级马道垂直方向持续向下沉降、水平方向背向边坡方向位移、二级马道持续向上抬升"的膨胀土浅层滑移特征。经研究决定采用伞形锚等进行局部渠段应急加固处理,并全程进行监测与监控。从监测成果来看,加固处理后,伞形土锚经历了初设期、调整期和稳定运行期3个阶段,边坡表面和内部土体经过近2个月的调整变形,目前锚索轴向应力稳定,变形趋于平衡稳定。全过程的加固处理与效果监测,为工程的风险管控与应急处理提供了科学依据、积累了经验。鉴于膨胀土深挖方边坡滑移的潜伏性、反复性以及长期性特点,后续要继续加强观测,对边坡的长期稳定性和伞型锚的长期效果进行研究。

The deep excavation slope of expansive soil in rainy season after a drainage ditch appeared uplift, local extrusion, and ac- companied by intermittent secondary cracks. The monitoring results also showed the characteristics of shallow soil displacement. Thever- tiealdirection of four class horse road of side slope continued downward trend and horizontal direction was opposite to the slope, the two class horse road continued upward trend. The study decided to strengthen the umbrella anchor and to monitor the whole process. From the monitoring results, the strengthening anchor umbrella had experienced in 3 period（ including the initial period, adjustment period and stable period）. The axial stress was stability after two months of the deformation and adjustment of surface slope and internal soil. The whole process of reinforcement and effect monitoring provided a scientific basis for risk control and emergency management of the project, and had accumulated some important experiences.