基于有限元和角位移场的深挖路堑稳定性分析

董舒静，赵瑜隆^*，展玉华，吴国华，马文龙

山东交通学院交通土建工程学院，山东 济南  250357

摘要：为保证公路深挖路堑的稳定性，测试风化岩石土的无侧限抗压强度、堆积密度、毛体积密度、颗粒级配与压碎值，采用有限元软件ABAQUS模拟边坡稳定性，分析深挖路堑的变形影响因素，采用切片法布设角位移传感器监测路堑变形，根据监测数据建立角位移场。结果表明：边坡失稳破坏可分为初始变形阶段、匀速变形阶段、临滑阶段3个阶段；第二横断面坡脚出现塑性应变区，随时间增加出现裂缝，坡脚抗滑能力下降，中下部岩石土向下运动，坡脚塑性区域缓慢向上扩展，运动一段时间后，边坡上部出现塑性区，下部塑性区迅速蔓延，直至贯通坡顶发生失稳破化；第三横断面坡顶易开裂，其余传感器监测角速度变化趋势及变化原因与第二横断面基本一致；角位移场深红色区域角位移最大，变形最显著，应在此位置放置传感器，以便及早预警。

关键词：路堑；稳定性；有限元分析；角位移场

Stability analysis of deep excavation trenches based on finite element method and angular displacement field

DONG Shujing，ZHAO Yulong^*，ZHAN Yuhua，WU Guohua，MA Wenlong

School of Civil Engineering, Shandong Jiaotong University, Jinan 250357, China

Abstract: To ensure the stability of deep excavations in road cuttings, the unconfined compressive strength, bulk density, apparent specific gravity, particle gradation, and crushing value of weathered rock soil are tested. Finite element software ABAQUS is used to simulate slope stability and analyze the factors influencing the deformation of deep excavations. Angular displacement sensors are deployed using the slicing method to monitor the deformation of the cuttings, and an angular displacement field is established based on the monitoring data. The results show that the instability and failure of the slope can be divided into three stages: initial deformation stage, uniform deformation stage, and near-sliding stage. A plastic strain zone appears at the foot of the slope in the second cross-section, with cracks emerging over time. The anti-sliding capacity of the foot of the slope gradually decreases, while the rock soil in the middle and lower parts moves downward, and the plastic zone at the foot of the slope slowly expands upward. After a period of movement, a plastic zone appears at the upper part of the slope, and the lower plastic zone rapidly spreads until it connects with the slope top, leading to instability failure. The slope top in the third cross-section is prone to cracking, and the trends and causes of angular displacement rate changes monitored by other sensors are basically consistent with those of the second cross-section. The deep red areas in the angular displacement field indicate the maximum angular displacement and the most significant deformation, and sensors should be placed in these locations for early warning.

Keywords: cutting; stability; finite element analysis; angular displacement field