基于锚杆监测的单滑动面边坡动态预警分析及安全分级

为完善边坡锚杆监测预警理论及促进锚杆监测法的广泛应用，基于锚杆实际受力特征和边坡不稳定演变规律，开展研究以确定监测锚杆预警阈值和单滑动面边坡安全分级。首先，对于锚杆监测单滑动面边坡，待加固锚杆及监测锚杆施工完，锚杆灌浆体强度已稳定，将短时间内应力调整及变形发展稳定后的边坡状态定义为边坡初始监测状态。接着，考虑滑动面的抗剪强度参数、滑动面上水压力和地震的不利演变，开展平面应变数值模拟预演分析，获得相对于边坡初始监测状态的监测锚杆轴力增量和序列。再相对于边坡初始监测状态，采用边坡极限平衡稳定分析法分别获得不利演变导致的边坡滑动力增量和抗滑力减少量，从而拟合二者与监测锚杆轴力增量和的函数，并建立边坡动态稳定系数与监测锚杆轴力和的计算公式。根据《建筑边坡工程技术规范》（GB 50330—2013）等关于边坡安全等级和预警的规定，将锚杆监测边坡预警等级划分为：蓝色无警、黄色预警、橙色预警和红色预警。最后，设计了锚杆监测单滑动面边坡算例及2个不利演变独立工况，阐述了采用该方法进行边坡动态预警分析及安全分级的流程。结果表明：针对类似边坡，先结合已有相关资料合理预判边坡影响因素的不利演变规律，再采用该方法进行分析，可达到良好的预警效果。

Dynamic Early Warning Analysis and Safety Classification of Slope with Single Sliding Plane Based on Monitoring of Fully Grouted Bolts

The purpose of this study is to improve the slope warning system using a monitoring method of fully grouted bolts and to promote the extensive application of this method. Experiments were conducted to determine the monitoring bolts' early warning thresholds and the safety classifications of slopes with a single sliding plane, based on the actual mechanical characteristics of bolts and the instability evolvement rule of slopes. First, for slopes with a single sliding plane using fully grouted bolt monitoring, when the strengthening and monitoring bolts are constructed and the grouting strength of bolts reaches a stable value in a short time, the slope reaches a steady state of stress adjustment and deformation development, which is identified as the initial monitoring state of the slope. Second, considering the negative evolutions of shear strength parameters of sliding planes, hydraulic pressure on the sliding plane, or earthquake, a numerical simulation analysis of plane strain is proposed to determine the sequences, relative to the initial monitoring state of the slope, on the incremental accumulation of monitoring fully grouted bolts' axial force. Third, relative to the initial monitoring state of the slope, the increment of slope sliding force and the reduction of slope anti-sliding force induced by the negative evolutions are obtained using limit equilibrium stability analysis of slope, thereby obtaining a fitting function with the incremental accumulation of monitoring fully grouted bolts' axial force, and establishing a computational formula on the dynamic stability factor of the slope with the accumulation of monitoring fully grouted bolts' axial force. According to the regulations on slope safety classification and early warning in the Technical Code for Building Slope Engineering (GB 50330-2013) etc., early warning classifications of the slope using a monitoring method of fully grouted bolts are blue:without alert, yellow:low alert, orange:mid alert, and red:high alert. Finally, the slope example with a single sliding plane using the monitoring method of fully grouted bolts and its two independent calculation conditions of negative evolutions was designed to interpret the process of the proposed method for dynamic early warning analysis and safety classification of the slope. For similar slopes, it is first suggested to reasonably pre-judge the negative evolvement rules of slope negative influences combining the existing relevant information, and then to apply the proposed method to complete the analysis and obtain a reliable early warning result.