基于极限分析法原理的浅埋隧道围岩受力监测对比分析

浅埋段隧道覆盖土性质随埋深和地形条件影响会发生变化。文章结合隧道上方覆盖层塌落体围岩自承能力及形成机理,基于塑性理论对隧道浅埋段围岩压力进行分析。研究结果表明:围岩压力随上部覆盖土层厚度增加而增大,且增加速率随覆盖层厚度的增大而减小,并逐步趋于固定值;覆土厚度和围岩力学参数是塌落面形状主要影响因素;浅埋偏压隧道的稳定性随着隧道两侧和底部支护结构功率增大而提高;随着围岩黏聚力、内摩擦角的增大,深埋侧和浅埋侧围岩压力都呈显著减小趋势。通过实际工程监测数据与新建公式计算值对比,证明了公式的适用性,为类似工程提供借鉴。

Contrast Analysis of Stress Monitoring of Surrounding Rock of Shallow Buried Tunnel Based on Principle of Limit Analysis Method

The properties of overburden soil in the shallow buried tunnel will change with the influence of buried depth and topographic conditions.The collapse surrounding rock self-supporting ability and formation mechanism of the overburden layer above the tunnel is combined in the paper.The shallow buried section surrounding rock pressure of tunnel is analyzed based on plasticity theory.The research results show that the surrounding rock pressure increases with the increase of the thickness of the overburden soil layer.The increasing rate decreases with the increase of the thickness of the overburden soil layer.It gradually tends to a fixed value.The thickness of overburden soil and mechanical parameters of surrounding rock are the main factors affecting the shape of collapse surface.The stability of the shallow-buried bias tunnel increases with the increase of the power of the supporting structure at both sides and bottom of the tunnel.The pressure of deep and shallow buried side surrounding rock decreases significantly with the increase of cohesion and internal friction angle of surrounding rock.The applicability of the formula is proved by comparing the actual engineering monitoring data with the calculated value of the new formula,thereby providing reference value for similar projects.